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X-Ray structural studies on the redox pair [Cr(CO)2(η-PhCCPh)(η-C6Me5H)]z (z = 0 and 1) show that one-electron oxidation of the neutral complex results in a shortening of the Cr–Calkyne bonds and a lengthening of the Cr–C(O) bonds, consistent with depopulation of a HOMO antibonding with respect to the metal–alkyne interaction. Oxidation leads to an increase in the substitutional lability of the Cr–CO bonds so that [Cr(CO)2(η-RCCR)(η-C6Me6)]+ (R = Ph or C6H4OMe-p) reacts with Lewis bases to give [Cr(CO)L(η-RCCR)(η-C6Me6)]+ {L = CNXyl, P(OMe)3 and P(OCH2)3CEt}, X-ray studies on which show a rotation of the alkyne to align with the remaining Cr–CO bond. ESR spectroscopic studies on [Cr(CO)L(η-RCCR)(η-C6Me6)]+ show delocalisation of the unpaired electron onto the alkyne ligand, consistent with its description as a three-electron donor. The cations [Cr(CO)L(η-RCCR)(η-C6Me6)]+ undergo both one-electron reduction and oxidation, and chemical oxidation of [Cr(CO){P(OCH2)3CEt}(η-p-MeOC6H4CCC6H4OMe-p)(η-C6Me6)]+ with AgPF6 gives the dication [Cr(CO){P(OCH2)3CEt}(η-p-MeOC6H4CCC6H4OMe-p)(η-C6Me6)]2+. Thus the two-electron alkyne of [Cr(CO)2(η-RCCR)(η-C6Me6)] is converted into the four-electron alkyne of [Cr(CO)L(η-RCCR)(η-C6Me6)]2+ by an ECE (E = electrochemical, C = chemical) process in which all of the intermediates have been fully characterised.

Maltol glucoside (3-(β- d -glucopyranosyloxy)-2-methyl-4H-pyran-4-one), 1 , was isolated from a preparation of the floral nectar from the New Zealand mānuka tree ( Leptospermum scoparium ). 1 eluted just after dihydroxyacetone in HPLC of underivatized nectar and showed a UV absorbance maximum of 258 nm. The structure of 1 was confirmed by NMR and high resolution mass spectrometry.

R.S. acknowledges the financial support from the Scottish Funding Council through EaStCHEM and SRDG grant HR07003. A potential end-point in the miniaturization of electronic devices lies in the field of molecular electronics, where molecules perform the function of single components. To date, hydrogen tautomerism in unimolecular switches has been restricted to the central macrocycle of porphyrin-type molecules. The present work reveals how H-tautomerism is the mechanism for switching in substituted quinone derivatives – a novel class of molecules with a different chemical structure. We hence reveal that the previous restrictions applying to tautomeric molecular switches bound to a surface are not valid in general. The activation energy of switching in a prototypical quinone derivative is determined using inelastic electron tunneling. Through computational modeling, we show that the mechanism underlying this process is tautomerisation of protons belonging to two amino groups. This switching property is retained upon functionalization by the addition of side groups, meaning that the switch can be chemically modified to fit specific applications. Postprint

Understanding the temporal and spatial development of the early Miocene Northland Volcanic Arc is critical to interpreting the patterns of volcanic activity in northern New Zealand through the late Cenozoic. The northwesterly trending arc is considered to have developed above a southwest‐dipping subduction system. The distribution of its constituent eruptive centres is described in terms of an eastern belt that extends along the eastern side of Northland and a complementary broad western belt which includes subaerial and submarine volcanic edifices. Critical examination of all 216 K‐Ar ages available, including 180 previously unpublished ages, and their assessment against tectonic, lithostratigraphic, seismic stratigraphic, and biostratigraphic constraints, leads us to deduce a detailed chronology of periods of activity for the various early (and middle) Miocene arc‐type volcanic complexes and centres of northern New Zealand: Waipoua Shield Volcano Complex (19–18 Ma, Altonian); Kaipara Volcanic C...

The complex [Mo(CO)(PhCCPh)2(η-C5Me5)][BF4] reacted with three equivalents of 2,6-dimethylphenyl isocyanide, CNxyl, to give the tris(isocyanide) complex [Mo(PhCCPh)(CNxyl)3(η-C5Me5)][BF4] 1. With four equivalents of CNxyl, alkyne–isocyanide coupling leads to the formation of the diiminometallacyclopentene [Mo{C(Nxyl)C(Ph)C(Ph)CNxyl}(CNxyl)2(η-C5Me5)][BF4] 2 which decomposes in thf at room temperature to give the tetrakis(isocyanide) complex [Mo(CNxyl)4(η-C5Me5)][BF4] 3. In dichloromethane, 2 gives the diiminocyclobutene xylNCC(Ph)C(Ph)CNxyl 4, the η2-iminoacyl complex [MoCl(CNxyl)2(η2-xylNCCH2Cl)(η-C5Me5)][BF4] 5, formed by an addition reaction with dichloromethane, and the metallacyclobutene complex [Mo{C(Ph)C(Ph)CN(H)xyl}(CNxyl)3(η-C5Me5)][BF4]26. Complex 5 is more efficiently synthesized by photolysis of 3 in dichloromethane, but the same reaction in chloroform produces the dichloromethyl complex [MoCl(CHCl2)(CNxyl)3(η-C5Me5)][BF4] 7 which thermally decomposes to [MoCl2(CNxyl)3(η-C5Me5)][BF4] 8. Reaction of 2 with HCl in diethyl ether results in protonation of the metallacyclic ring and formation of the iminium metallacyclopentene [MoCl{C(Nxyl)C(Ph)C(Ph)CN(H)xyl}(CNxyl)2(η-C5Me5)][BF4] 9. Compound 3 is oxidised by AgBF4 to give the molybdenum(IV) complex [MoF(CNxyl)4(η-C5Me5)][BF4]210. The molecular structures of 3–6, 7/8 and 10 have been determined by X-ray crystallography.

U–Pb (SHRIMP) detrital zircon age patterns are reported for 12 samples of Permian to Cretaceous turbiditic quartzo‐feldspathic sandstone from the Torlesse and Waipapa suspect terranes of New Zealand. Their major Permian to Triassic, and minor Early Palaeozoic and Mesoproterozoic, age components indicate that most sediment was probably derived from the Carboniferous to Triassic New England Orogen in northeastern Australia. Rapid deposition of voluminous Torlesse/Waipapa turbidite fans during the Late Permian to Late Triassic appears to have been directly linked to uplift and exhumation of the magmatically active orogen during the 265–230 Ma Hunter‐Bowen event. This period of cordilleran‐type orogeny allowed transport of large volumes of quartzo‐feldspathic sediment across the convergent Gondwanaland margin. Post‐Triassic depocentres also received (recycled?) sediment from the relict orogen as well as from Jurassic and Cretaceous volcanic provinces now offshore from southern Queensland and northern New Sout...

Reaction of (4,4′–bis–tert–butyl–2,2′–dipyridyl) platinum bis–alkynyl [(tBu2bipy)Pt(CCR)2] (R=C6H4Me 1a, SiMe3 1b) with Group 11 metal thiocyanate salts (M=Cu, Ag) affords 1:1 mixed-metal complexes [(tBu2bipy)Pt(CCR)2M(SCN)] (M=Cu, R=C6H4Me 2a, SiMe3 2b; M=Ag, R=C6H4Me 3a, SiMe3 3b). X-ray analyses of the complexes 2a and 3b show that the group 11 metal is bonded in an η2 fashion to two carbon–carbon triple bonds so that the co-ordination geometry is trigonal planar. The Pt atom geometry in both complexes is square planar. An electrochemical study of the copper complexes 2a and 2b reveals one fully reversible one electron reduction that is consistent with the first reduction of the co-ordinated bipyridyl ligand. There is also an irreversible one electron oxidation that corresponds to the CuI to CuII transition.

K‐Ar and Rb‐Sr ages of Marlborough Schist and Pelorus Group metasediments show coherent regional metamorphic/cooling age patterns, irrespective of their terrane protolith, in which ages are primarily inversely related to metamorphic grade and, more locally, with distance from the Picton Fault Zone. The oldest ages, from the lowest grade (prehnite‐pumpellyite facies, textural grade 1'IIA) Pelorus Group are mainly in the range 175–200 Ma, indicating regional metamorphism occurred at least in earliest Jurassic or latest Triassic times. Progressive cooling of Marlborough Schist resulted in a spectrum of cooling ages, mainly 110–180 Ma, which reflects slow regional uplift during the Jurassic and Early Cretaceous. Some disruption of this pattern occurred at the Picton Fault Zone where post‐Early Cretaceous movement has juxtaposed high and low structural levels. Initial 87Sr/86Sr isotopic ratios (i) at the time of metamorphism (t), derived from Rb‐Sr whole‐rock isochron data, further characterise terran...

The novel compound 2-cyanaminofluoren-9-one (HL) has been synthesized, and is readily deprotonated to form the corresponding cyanamide anion L–. This has been isolated as the Tl+L– and AsPh4+L– salts. The UV/visible spectra of HL and AsPh4+L– show the same amine to carbonyl charge transfer transition seen in other aminofluorenones, although at longer wavelengths. The compound AsPh4+L– undergoes the reversible one electron reduction typical of fluorenones, whilst HL undergoes an irreversible reduction. The crystal structure of AsPh4+L– was determined and related to the solvatochromic behaviour of the L– anion. Some simple EHMO calculations have been carried out on the L– anion of AsPh4+L–, which show the cyanamide based HOMO and carbonyl based LUMO involved in the aforementioned CT transition. The thallium salt Tl+L– has also been used as a transmetallating agent in reaction with trimethyltin chloride to produce the corresponding tin cyanamide complex [SnMe3L], and in reaction with (triphenylphosphine)gold chloride to produce the first reported gold cyanamide compound [AuL(PPh3)], whose crystal structure has been determined.

Reaction of the dicarbon-containing complex [Ru5(µ5-C2)(µ-SMe)2(µ-PPh2)2(CO)11] 1 with monosubstituted alkynes HCCR (R = Ph, But or SiMe3) yielded [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)10] (R = Ph, But or SiMe3) in which the Ru5 pentagon in 1 is retained. Coupling of the C2 and alkyne moieties forms a CCCHCR ligand which in combination with one Ru atom forms a metallacycle. The unsubstituted terminal carbon has a strong carbidic interaction with four of the Ru atoms. Carbonylation of the R = Ph and SiMe3 complexes yields [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)11] (R = Ph or SiMe3), in which one Ru atom has been extruded from the cluster, although retained by co-ordination to bridging PPh2, SMe and hydrocarbon ligands. A minor product in each case was identified as [Ru5{µ5-CC[C(O)SMe]CHCR}(µ-SMe)(µ-PPh2)2(CO)10 (R = Ph or SiMe3). Here, the organic ligand is formed by combination of the CCCHCR ligand with CO and one of the SMe groups and is attached to an Ru5 core with an open-envelope conformation. Pyrolysis of [Ru5(µ-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)11] afforded [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)10] and [Ru5(µ5-CCCHCR)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9] (R = Ph or SiMe3), in which one SMe group becomes triply bridging. The complex [Ru5{µ5-CC(CHCSiMe3)C(=CHSiMe3)CO}(µ-SMe)2(µ-PPh2)2(CO)8], in which the organic ligand, formed by combination of CO, HC2SiMe3 and CCHSiMe3 molecules, is attached to the opposite side of the open-envelope cluster from that in [Ru5{µ5-CC[C(O)SMe]CHCR}(µ-SMe)(µ-PPh2)2(CO)10], has also been isolated. The structures of five complexes were determined from single-crystal X-ray studies.

Reaction of the dicarbon-containing complex Ru5(µ5-C2)(µ-SMe)2(µ-PPh2)2(CO)11 1 with diphenylethyne gave as major products Ru5(µ5-CCCPhCPh)(µ-SMe)2(µ-PPh2)2(CO)10 2 and Ru5(µ5-CCPhCPh)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9 3. The only product from the reaction between 1 and but-2-yne was identified as Ru5(µ5-CCCMeCMe)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9 4. Pyrolysis of 2 gave 3. Carbonylation of 3 yields the complex Ru5(CCCPhCPh)(µ-SMe)2(µ-PPh2)2(CO)11 5, further heating of which regenerated a mixture of 2 and 3. The structures of 2 and 3 were determined from single crystal X-ray studies. The Ru5 clusters in both complexes adopt the open-envelope conformation, the Ru4 rhombus being planar in 2, but bent across the Ru(3)· · ·Ru(5) diagonal by 39.6° in 3. The organic ligand is formed by coupling of the C2 group in 1 with the alkyne and is attached by three of the four carbons in 2 and by all four in 3, atom C(1) being strongly attached to the Ru4 rhombus. In 3, atoms C(1,2,3,4) have an η4 interaction with Ru(4).

New U–Pb detrital zircon ages from Triassic metasandstones of the Torlesse Terrane in New Zealand are compared with 40Ar/39Ar muscovite data and together, reveal four main source components: (i) major, Triassic–Permian (210–270 Myr old) and (ii) minor, Permian–Carboniferous (280–350 Myr old) granitoids (recorded in zircon and muscovite data); (iii) minor, early middle Palaeozoic, metamorphic rocks, recorded mainly by muscovite, 420–460 Myr old, and (iv) minor, Late Precambrian–Cambrian igneous and metamorphic complexes, 480–570 Myr old, recorded by zircon only. There are also Proterozoic zircon ages with no clear grouping (580–1270 Myr). The relative absence of late Palaeozoic (350–420 Myr old) components excludes granitoid terranes in the southern Lachlan Fold Belt (Australia) and its continuation into North Victoria Land (East Antarctica) and Marie Byrd Land (West Antarctica) as a potential source for the Torlesse. The age data are compatible with derivation from granitoid terranes of the northern New England Orogen (and hinterland) in NE Australia. This confirms that the Torlesse Terrane of New Zealand is a suspect terrane, that probably originated at the NE Australian, Permian–Triassic, Gondwanaland margin and then (200–120 Ma) moved 2500 km southwards to its present New Zealand position by the Late Cretaceous (90 Ma). This sense of movement is analogous to that suggested for Palaeozoic Mesozoic terranes at the North American Pacific margin.

A highly crystalline powder sample of NaP with a Si/Al ratio of 1.0 was synthesized and ion-exchanged against Ca, yielding a monophasic sample of a CaP zeolite, Ca 4 Al 8 Si 8 O 32 ·18.9H 2 O. The crystal structure of CaP was determined from X-ray (synchrotron) data in the monoclinic crystal system, space group P2 1 / c ( a =10.02415 A, b =10.6130 A, c =9.8333 A, β =92.292°, R p =0.0677, w R P =0.0648). It is found to be very similar to the structure of the natural occuring zeolite, gismondine. The close structural relationship between the synthetic group of P zeolites and natural zeolites with gismondine framework (gismondine, garronite, amicite and gobbinsite) is discussed.

Square-planar Pt(II) complexes of the bis(mesitylimino)acenaphthene (mesBIAN) ligand are emissive from a MMLL'CT excited state in a dichloromethane solution at room temperature. Investigation of the nature of the frontier orbitals in these near-IR emitters by a combination of emission spectroscopy, electron paramagnetic resonance spectroscopy, and density functional theory calculations suggests that emission is enabled by the presence of low-lying ligand pi* orbitals on the mesBIAN.

Geochronological studies of the eastern Otago Schist and adjacent metagreywacke sequences are applied to their structural/metamorphic history and schist protoliths. Rb‐Sr whole‐rock isochron and K‐Ar total‐rock ages are inversely correlated with metamorphic grade (both in terms of mineral facies and textural zones), dating the time of peak metamorphism and/or postmetamorphic cooling. On the northern flank of the schists, older ages (200–230 Ma) date initial burial metamorphism and deformation in late Triassic ‐ early Jurassic times. Younger age patterns (to 115 Ma) reflect either (1) higher grade metamorphism during a single event followed by long‐continued uplift, or (2) early burial metamorphism at >200 Ma with a second, regional metamorphism between then and 115 Ma followed by rapid uplift. Initial Sr isotopic ratios derived from isochrons indicate that protoliths originate in two terranes. North of Dunedin, initial 87Sr/86Sr ratios range from 0.7064 to 0.7092, similar to Torlesse Terrane (Rak...

The reaction between [Ru 5 (µ 5 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 11 ] 1 and CO (30 atm) yielded [Ru 5 (µ 4 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 13 ] 2 and [Ru 4 (µ 4 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 10 ] 3, both characterised by single-crystal X-ray crystallography. In 2, addition of 2CO results in the net cleavage of two Ru–Ru bonds and expansion of the resulting Ru 3 cluster. The C 2 ligand bridges one edge of the Ru 3 core and the isolated Ru–Ru bonded fragment in a µ,µ-η 1 ,η 2 mode, albeit with asymmetric Ru–C 2 π interactions. In 3, one Ru atom has been excised from the cluster present in 1. One Ru–Ru bond is bridged by two SMe groups as a result of migration of one of these. Although the C 2 ligand bridges all four metal atoms, only two Ru – Ru bonds are present, with the non-bonded Ru · · · Ru vector being bridged by PPh 2 . Extended-Huckel molecular orbital calculations have been used to rationalise the observed structures.

The reaction between [Ru 5 (µ 5 -C 2 PPh 2 )(µ- PPh 2 )(CO) 13 ] and Me 2 S 2 yielded [Ru 5 (µ 5 -C 2 PPh 2 )(µ- SMe) 2 (µ-PPh 2 )(CO) 13 ] as the major product. When heated the latter yielded the dicarbon complexes [Ru 5 (µ 5 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 12 ] and [Ru 5 (µ 5 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 11 ]. In large-scale preparations of the latter four minor products were isolated: two isomers of [Ru 5 (µ 5 -C 2 PPh 2 )(µ- SMe) 2 (µ-PPh 2 )(CO) 12 ], the tetranuclear complex [Ru 4 (µ 4 -C 2 PPh 2 )(µ- SMe) 2 (µ-PPh 2 )(CO) 10 ] and [Ru 5 (µ 5 -C 2 )(µ-SMe) 4 ( µ-PPh 2 ) 2 (CO) 10 ]. The latter is also formed by direct reaction of [Ru 5 (µ 5 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 11 ] with Me 2 S 2 . All new complexes have been fully characterised by single-crystal X-ray studies. In the three Ru 5 (C 2 PPh 2 ) complexes the C 2 PPh 2 ligand acts as a seven-electron donor, whereas in the Ru 4 complex it donates only five electrons to the cluster. In the C 2 complexes, the different C–C separations [between 1.26(2) and 1.305(5) A] suggest a variable degree of interaction with the metal core (electron donation and back-bonding), the ligand formally donating either six or four electrons to the cluster. This is borne out by the Ru–Ru separations, average values of which range between 2.791 and 2.916 A. The conversion of [Ru 5 (µ 5 -C 2 PPh 2 )(µ- PPh 2 )(CO) 13 ] into [Ru 5 (µ 5 -C 2 )(µ-SMe) 2 ( µ-PPh 2 ) 2 (CO) 11 ] involves sequential formation of several of these complexes, which reactions are discussed.

When Ru 5 ( μ 5 -C 2 PPh 2 )( μ -PPh 2 )(CO) 13 ( 1 ) is treated with dppm, Ru 5 ( μ 5 -C 2 PPh 2 )( μ -PPh 2 )(dppm)(CO) 12 (bd3) is formed, in which the dppm ligand chelates one Ru atom; the resulting Ru 5 cluster is a spiked butterfly. Reaction between 1 and PPh 2 C 6 H 4 NH 2 -2) yields Ru 5 ( μ 5 -C 2 H)( μ -PPh 2 ) 2 ( μ -PPh 2 C 6 H 4 NH-2)( μ -CO)(CO) 10 ( 4 ) as the major product, in which the deprotonated anilinosphoshine ligand is attached to a triangulated square Ru 5 core with an open envelope conformation. In a similar reaction with (PPh 2 ( C 6 H 4 CH=CH 2 -2) the major product further reacts to give a number of complexes, including Ru 4 { pgm 4 -C 2 PPh 2 [Ru( μ -Oh)( C , P -2-CHMeC 6 H 4 PPh 2 )(CO) 2 ]}-( μ -PPh 2 )(CO) 10 ( 6 ), formed by incorporation of H 2 O into the cluster; in this case, Ru atom interacts with an Ru 4 butterfly by means of a μ-OH ligand and coordination to the PPh 2 group of the C 2 PPh 2 ligand. A minor product is Ru 5 ( μ -H) 5 { μ 5 -PPh 2 C 2 CH=C(C 6 H 4 PPh 2 -2)}( μ -PPh 2 )(CO) 11 ( 7 ), in which the diphosphine ligand has been formed by linkage of the C 2 PPh 2 ligand with the olefinic portion of the PPh 2 ( C 6 H 4 CH=CH 2 ) ligand with concomitant migration of two atoms to the cluster. The resulting μ 5 -PPh 2 C 2 CHCC 6 H 4 PPh 2 fragment is attached to a “bow-tie” Ru 5 cluster by the two P atoms and all four cardon atoms of the PC 4 chain.

Reaction of Ru5(μ5-C2PPh2)(μ-PPh2)(CO)13 (I) with 5-chloro-4-chloromethyl-2,4-dimethylpent-1-ene in refluxing CHCl3 affords Ru5(μ5-C2)(μ-PPh2)2(μ-Cl)2(CO)11 (3) and Ru5(μ-H){μ5-CC(PPh2)}(μ-Cl)(μ-PPh2(CO) (4). The crystal structures of 3 and 4 were determined by X-ray crstallography. Complex 3 is the second example of a cluster containing a C2 ligand sitting on top of a partially disordered puckered pentagonal Ru5 cluster, with one carbon strongly bonded (σ) to one Ru atom (RuC, 1.937 (9) A) with the C2 moiety interacting in π fashion with the other four metal atoms. Complex 4 retains the C2PPh2 ligand of the precursor, sitting on an “open-envelope” Ru5 cluster; one carbon is strongly bonded to four Ru atoms of a pseudosquare Ru4 array.

The aim of this critical review is to provide a broad but digestible overview of mechanochemical synthesis, i.e. reactions conducted by grinding solid reactants together with no or minimal solvent. Although mechanochemistry has historically been a sideline approach to synthesis it may soon move into the mainstream because it is increasingly apparent that it can be practical, and even advantageous, and because of the opportunities it provides for developing more sustainable methods. Concentrating on recent advances, this article covers industrial aspects, inorganic materials, organic synthesis, cocrystallisation, pharmaceutical aspects, metal complexes (including metal-organic frameworks), supramolecular aspects and characterization methods. The historical development, mechanistic aspects, limitations and opportunities are also discussed (314 references).

An improved protocol for the selective dilithiation of [V(η(5)-C(5)H(5))(η(7)-C(7)H(7))] has been developed, which afforded [V(η(5)-C(5)H(4)Li)(η(7)-C(7)H(6)Li)]·PMDTA (5; PMDTA=N,N,N',N'',N''-pentamethyldiethylenetriamine) in almost quantitative yield (98%). In the solid state, the species features a dimeric structure with two terminal and two bridging lithium atoms, with the latter connecting both sandwich subunits. Reaction with suitable Group 4 dihalide compounds enabled the isolation of highly strained silicon- and germanium-bridged [1]trovacenophanes 6 and 7. Similarly, reaction of 5 with Cl(2)Sn(2)tBu(4) afforded the rather unstrained complex [V(η(5)-C(5)H(4))(η(7)-C(7)H(6))Sn(2)tBu(4)] (8), which together with 7 represent the first trovacenophanes to incorporate heavier analogues of silicon in the ansa-bridge. Ring-opening polymerization reactions of [V(η(5)-C(5)H(4))(η(7)-C(7)H(6))SiRR'] (2a: R=R'=Me; 6: R=Me, R'=iPr) were performed by heating in a solution of toluene in the presence of the Karstedt catalyst, which resulted in the formation of the corresponding soluble poly(trovacenylsilanes) in yields of 41 and 33%, respectively. As estimated by gel permeation chromatography (GPC), the macromolecules possess molecular weights of M(n)=10,010 and 5580 g mol(-1) with polydispersity indices of 2.31 and 1.64 for 9 and 10, respectively. ESR spectroscopic studies on 9 and 10 revealed only a single broad resonance in each case without any identifiable (51)V hyperfine coupling.

International audience; The Late Cretaceous clastic coastal sediments of New Caledonia are contemporaneous with the latest stages of the eastern Australian marginal rifting. As such, they record the erosion of basement terranes located on uplifted and tilted blocks and a contemporaneous volcanic activity. Detrital zircon populations contain two major components, the younger of which is Early Cretaceous, and the older Early Paleozoic and Precambrian. Following recent advances in the knowledge of detrital zircon content of basement terranes, and at variance with previous interpretations, that hypothesised a possible direct Australian provenance for Precambrian zircons, the detrital zircon record of these syn-rift sediments allows a local recycled provenance to be established. In consequence, this new evidence confirms that New Caledonia was already isolated from Australia as early as Coniacian time (ca. 89-85 Ma) a fact consistent with the development of faunal and floral endemism at that period. The prominent abundance of Early Cretaceous detrital zircons also establishes the importance of a previously unrecorded Early Cretaceous magmatism in the area.

Reactions of [Co2(CO)8] with [{Mn(CO)11}2(µ-bdpp)][Mn Ru3, Os3, Re3(µ-H)3 or Ru4(µ-H)4; bdpp PPh2C2C2PPh2] afforded [{Mn(CO)11}2{µ-PPh2[C2Co2(CO)6]C2 PPh2}][Mn Ru31, Os32, Re3(µ-H)33 or Ru4(µ-H)44] in which the Co2(CO)6 moiety bonds to one of the CC triple bonds of the bridging bdpp ligand. Pyrolysis of 1 yielded [{Ru3(CO)11}{µ-PPh2[C2Co2(CO)6]C2}{Ru2(µ-PPh2)(CO)6}]5, which is formed by concomitant addition of a P–C(sp) bond to one Ru3 cluster and elimination of a Ru(CO)4 fragment. In [{Os3(CO)11}(µ-PPh2C2C2){Co2Os3(µ-PPh2)(CO)13}]8, obtained by heating 2, the Co2Os3 cluster consists of three edge-sharing triangles; the C2 fragment interacts with all five metal atoms. Reaction of the mixed-metal complex [{Os3(CO)11}(µ-bdpp){Re3(µ-H)3(CO)11}]10 with [Co2(CO)8] yielded a 1:1 isomeric mixture of [{Os3(CO)11}{µ-PPh2[C2Co2(CO)6]C2PPh2}{Re3(µ-H)3(CO)11}]11a and [{Re3(µ-H)3(CO)11}{µ-PPh2[C2Co2(CO)6]C2PPh2}{Os3(CO)11}]11b. Pyrolysis of 11a afforded [Co2Os3Re{µ6-C2CCH(PPh 2)}(µ-PPh2)(µ-CO)2(CO)14]12 in which all three transition metals form a cluster about the C4P fragment of the original bdpp ligand, which has also added one H atom to the carbon adjacent to the PPh2 group. The second PPh2 group bridges an Os–Os bond. Molecular structures of 5, 8 and 12 were determined by X-ray crystallography.

Various preparations of some 2′-tetrahydropyren-2-yloxychalcone epoxides and removal of their tetrehydropyranyl (THP) protective groups in slightly aqueous acidic dioxane are described. So synthesised were 2′-hydroxy-6′-isopropoxy- and 2′-hydroxy-6′-methoxychalcone epoxide, as well as the 2-CF3, 4-Cl and 4-NO2 analogues of the latter, 2′,4′-dihydioxy-6′-methoxychalcone epoxide was similarly prepared. In some other 6−'methoxy cases protective group removal was accompanied by epoxide solvolysis and the corresponding α,β-dihydroxydihydrochalcone was the only isolable product [2-OMe, 4-OMe, 3,4,5-(OMe)3 cases] or a byproduct [4-Me case]. Similarly prepared by THP removal were 2′-hydroxy-4′-methoxychalcone epoxide and 2′,4′-dihydioxychalcone epoxide, whereas an attempt to convert 2′,6′-ditetrahydropyranyloxychalcone epoxide into 2′,6′-dihydroxychalcone epoxide gave the product of cyclisation of the latter, 3,5-dihydroxyflavanone.

Several complexes of the acetylenic ditertiary phosphine, Ph2PC2C2PPh2, containing Mo, W, Fe, Ru or Au have been prepared; one CC triple bond in the Mo, W or Fe derivatives has been co-ordinated to Co2(CO)6 or Pt(PPh3)2 groups. Crystal structure determinations of [{Fe(CO)4}2(µ-PPh2C2C2PPh2)]3 and [Co2{µ-η2-[(OC)5W(PPh2)]CC [C2(PPh2)W(CO)5]}(CO)6]7 show that the P-bonded M(CO)n groups take up transoid positions; in 3, the PCCCCP chain, which is situated about a centre of inversion, is nearly linear [P–C–C, 173.2(5); C–C–C 179.7(6) for molecule a and 174.7(5) and 177.6(6)°, respectively, for molecule b] with CC distances of 1.192(7)A[1.201(6)A, molecule b]. In 7, co-ordination of the Co2(CO)6 group to one CC bond lengthens that bond by 0.13 A, compared with the unco-ordinated CC bond, and induces bend-back of the substituents of 141–143(1)°(PPh2) and 145–146(1)°(C2PPh2). Crystals of 3 are triclinic, space group P, a= 11.261(1), b= 12.456(2), c= 13.061(2)A, α= 79.23(2), β= 75.73(1), γ= 78.75(2)°, Z= 2; 2870 data were refined to R= 0.042, R′= 0.046. Crystals of 7 are triclinic, space group P, a= 17.940(4), b= 19.695(4), c= 16.449(2)A, α= 111.92(1), β= 108.83(1), γ= 100.29(2)°, Z= 4; 5942 data were refined to R= 0.055, R′= 0.056.

Latest Precambrian to Ordovician metasedimentary successions and Cambrian-Ordovician and Devonian-Carboniferous granitoids form the major part of the basement of southern Zealandia and adjacent sectors of Antarctica and southeast Australia. Uplift/cooling ages of these rocks, and local Devonian shallow-water cover sequences suggest that final consolidation of the basement occurred through Late Paleozoic time. A necessary consequence of this process would have been contemporaneous erosion and the substantial development of marine sedimentary basins at the Pacific margin of Zealandia. These are found nowhere at the present day, suggesting that the basins have been lost by tectonic erosion, perhaps in a margin-parallel dextral translation similar to late Paleozoic-Mesozoic suspect terranes of New Zealand. Aprobable detrital zircon age pattern is assembled for these lost Zealandia sediments, and then compared with those of pre-Jurassic (probable Triassic to Devonian) metasedimentary rocks in the Chilean archipelago. Significant Mesoproterozoic, latest Neoproterozoic-Cambrian and Devonian-Carboniferous detrital zircon age components are common to both, thus supporting a possible Chilean terrane destination for these 'lost terranes of Zealandia'. Las sucesiones metasedimentarias del Precámbrico tardío al Ordovícico y granitoides del Cámbrico-Ordovícico y Devónico-Carbonífero constituyen la mayor parte del basamento del sur de Zealandia y sectores adyacentes de la Antartica y el sudeste de Australia. Las edades de enfriamiento/alzamiento de estas rocas y la cobertura local de secuencias de aguas someras del Devónico, sugieren que la consolidación definitiva del basamento se produjo durante el Paleozoico tardío. Una consecuencia necesaria de este proceso habría sido la erosion contemporánea y el desarrollo sustancial de cuencas sedimentarias marinas en el margen del Pacífico de Zealandia. Estas no se encuentran en ninguna parte en la actualidad, lo que sugiere que las cuencas se han perdido por erosion tectónica, tal vez en una traslación dextral paralela al margen similar a los terrenos del Paleozoico tardío-Mesozoico de Nueva Zelanda. Hay una agrupación que da un probable patrón de edad de circones detríticos para estos sedimentos de la perdida Zealandia, comparables con aquellos de rocas metasedimentarias del pre-Jurásico (probable Triásico a Devónico) del archipiélago chileno. Importantes componentes de edades de circones detríticos del Mesoproterozoicos, Neoproterozoico tardío-Cámbrico y Devónico-Carbonífero son comunes a ambas regiones, favoreciendo así un posible destino chileno para estos 'terrenos perdidos de Zealandia'.

Monometallic complexes of the tetrakis(pyrazolyl)borate ligand [ML(2){B(pz)(4)}] {M = Rh, Ir; L(2) = eta-cod, eta-nbd, (CO)(2), (CO)(PPh(3))} have two free pyrazolyl rings which can be coordinated to a second ML(2) unit to give the dimeric compounds [L(2)M{mu-B(pz)(4)}ML(2)](+), and to a metal halide to give heterobimetallic species [L(2)M{mu-B(pz)(4)}M'Cl(2)]. (1)H NMR spectroscopy shows that [(eta-cod)Rh{mu-B(pz)(4)}Rh(eta-cod)](+) 1(+), [(eta-nbd)Rh{mu-B(pz)(4)}Rh(eta-nbd)](+) 2(+), [(eta-cod)Ir{mu-B(pz)(4)}Ir(eta-cod)](+) 3(+) and [(CO)(2)Rh{mu-B(pz)(4)}Rh(CO)(2)](+) 4(+) are fluxional at room temperature. Cooling a solution of [(eta-cod)Rh{mu-B(pz)(4)}Rh(eta-cod)](+) 1(+) to -90 degrees C slows the fluxional process, which involves inversion of the two B-(N-N)(2)-M six-membered rings. Attempts to synthesise the asymmetric complexes [(eta-cod)Rh{mu-B(pz)(4)}Rh(eta-nbd)](+) 7(+), [(eta-cod)Rh{mu-B(pz)(4)}Ir(eta-cod)](+) 8(+) and [(eta-cod)Rh{mu-B(pz)(4)}Rh(CO)(2)](+) 9(+) produced a mixture of [L(2)M{mu-B(pz)(4)}ML(2)](+), [L'(2)M'{mu-B(pz)(4)}M'L'(2)](+) and the desired species. The heterobimetallic complexes [L(2)Rh{mu-B(pz)(4)}M'Cl(2)] (M' = Co, L(2) = eta-cod 10; M' = Co, L(2) = eta-nbd 11; M' = Co, L = CO 12; M' = Co, L(2) = (CO)(PPh(3)) 13; M' = Zn, L(2) = eta-cod 14; M' = Zn, L(2) = eta-nbd 15; M' = Pd, L(2) = eta-cod 16) possess square planar Rh(I) linked to square planar Pd(II) or tetrahedral Zn(II) and Co(II) centres. The paramagnetic Co(II) complexes give (1)H NMR spectra with signals shifted over a range of 75 ppm. The UV-Vis spectra of 10-13 show four bands, one MLCT at Rh and three d-d transitions arising from the splitting of the (4)T(1)(P) excited state due to approximate C(2v) symmetry at Co.

Solid-state reactions of palladium(II) and platinum(II) chloride complexes with imidazole (Him) and pyrazole (Hpz) or their hydrochloride salts are shown to produce metal complex salts and coordination compounds. Thus, K(2)[MCl(4)] or MCl(2) can be ground with imidazolium chloride ([H(2)im]Cl) to produce the salts [H(2)im](2)[MCl(4)] (M = Pd, 1; Pt, 5), which can then be dehydrochlorinated in the solid state to produce the coordination compounds trans-[PdCl(2)(Him)(2)] 3 or cis-[PtCl(2)(Him)(2)] 6. The complex cis-[PdCl(2)(Him)(2)] 2 is produced when Pd(OAc)(2) is ground with [H(2)im]Cl. Reaction of platinum chloride reagents with imidazole (Him) also produces cis-[PtCl(2)(Him)(2)] 6, but reaction of imidazole with analogous palladium chloride reagents first produces [Pd(Him)(4)]Cl(2) 4 which then slowly converts to trans-[PdCl(2)(Him)(2)] 3. Grinding pyrazolium chloride with K(2)[MCl(4)] produces [H(2)pz](2)[MCl(4)] (M = Pd, 7; Pt, 10), which may also be dehydrochlorinated in the solid state to produce the coordination compounds trans-[PdCl(2)(Hpz)(2)] 8 or cis-[PtCl(2)(Hpz)(2)] 11. Grinding K(2)[PdCl(4)] or PdCl(2) with pyrazole gives [Pd(Hpz)(4)]Cl(2) 9, which is then slowly converted into trans-[PdCl(2)(Hpz)(2)] 8. Grinding PtCl(2) with Hpz generates [Pt(Hpz)(4)]Cl(2) 12, but using K(2)PtCl(4) as the metal source does not generate the same product. The single-crystal structures of 8, a new polymorph of 11 and [H(2)pz](2)[PtCl(6)].2H(2)O (isolated as a decomposition product) are reported for the first time, and the structures of 5 and 10 have been solved ab ibitio from XRPD data.

Three 3,6-difluoro-1,2,4,5-tetrakis(amino)benzene compounds, bearing dimethylamino (1), piperidin-1-yl (3), or morpholin-1-yl (5) substituents, have been synthesized and subsequently defluorinated to give the corresponding 1,2,4,5-tetrakis(amino)benzene compounds 2, 4, and 6; the crystal structures of compounds 1, 4, and 6 have been obtained. Cyclic voltammetry shows that all six compounds will lose two electrons to form dications, and the use of suitable oxidizing agents has allowed isolation and crystallographic characterization of the dications 2(2+) and 6(2+) (as [PF(6)](2) salts) and 4(2+) (as a [I(5)][I(3)] salt). The separation DeltaE between the loss of the first electron and the second varies between compounds, from 0.23 V in 1 to 0.01 V in 6. Electrochemical studies involving the use of the noncoordinating electrolyte [Bu(4)N][B{C(6)H(3)(CF(3))(2)}(4)] show that it is possible to increase this separation, stabilizing the intermediate monocationic phase, and this has allowed the isolation and crystallographic characterization of the radical salts 2[B{C(6)H(3)(CF(3))(2)}(4)] and 4[B{C(6)H(3)(CF(3))(2)}(4)], the first radical cations of this family to be isolated. DFT studies of the ion pairing between oxidized forms of 1 and 2 and anions imply that the location of the ion pairing is different in the two species.

International audience; New U-Pb dating of detrital zircon and geochemical features of Permian-Mesozoic arc-derived volcanic rocks and volcaniclastic turbidites (greywackes), when compared to the volcanic rocks associated with unconformable Late Cretaceous shallow-water sediments, reveal that subduction in New Caledonia, once thought to be extinct in the Late Jurassic (ca. 150 Ma), was still active at least from ca. 130 Ma to 95 Ma. The accumulation of volcanic arc-derived sediments during the late Early Cretaceous suggests that, as in New Zealand, active margin activity went on for a short time in spite of the assumed subduction jamming by the Hikurangi plateau at ca.100 Ma. Meanwhile, the rift-related magmatic activity that preceded the marginal breakup migrated eastward: from ca. 130 Ma (130-95 Ma) in eastern Australia, 110 Ma (110-82 Ma) in New Zealand, and finally ca. 89 Ma (89-83 Ma) in New Caledonia, and generated large volumes of silicic magma. In contrast, marginal basins opened synchronously at ca. 83 Ma when the stretched continental crust finally broke out. In general, intraplate and volcanic-arc signatures coexisted in Cretaceous syn-rift magmas. Therefore, the Australian marginal breakup appears to be the final effect of continuous southward unzipping of Gondwana that interfered with the subduction-modified mantle wedge of the Mesozoic active margin. The occurrence of lateral flow of the upper asthenospheric mantle due to the rapidly eastward migrating Australian plate margin possibly prevented the formation of a volcanic arc at the eastern end of the system.

Analysis of the pH-rate profile for the cyclisation of the monoanion of 2′-hydroxychalcone epoxide which gives 3-hydroxyflavanone and of some 6′-alkoxy-substituted analogues which give mostly hydrate, gives rate coefficients which quantify the preference for α over β cyclisation when 6′-substituents are present. These are considered in terms of stereoelectronic factors which may be responsible for the preference. Also reported are rate coefficients for the subsequent reaction of aurone hydrates in which aurones and coumaranones are formed.

Twenty‐one basanites from a regional dike swarm in the Awatere River, Winterton River and Gladstone Stream, Awatere Valley area, Marlborough, have been analysed (major and trace elements) and dated by the K‐Ar method. K‐Ar ages of the dikes range between 100 and 60 Ma. The younger age extends the previously determined age range of igneous activity in the Awatere Valley (fossil age of volcanic activity; K‐Ar and fission‐track ages of volcanic and plutonic rocks) of 103–90 Ma for another 30 Ma into early Tertiary time. Considering only phenocryst‐free or phenocryst‐poor dikes, SiO2, total alkalis, Ba, Ce, Y, Zr, and Differentiation Index (D.I.) increase with decreasing age, and MgO, CaO, Cr, Cu, Ni, Sc, and Mg number decrease. This variation reflects a time‐dependent evolution of magma composition controlled by early‐stage olivine/pyroxene fractionation, gradually increasing sodic enrichment of plagioclase, and later crystallisation of K‐feldspar.

Reaction of the labile triosmium cluster [Os3(CO)10(NCMe)2] with the thienyl substituted diyne [(C4H3S)C2C2(C4H3S)] affords [Os3(CO)10{μ3-η2-(C4H3S)C2C2(C4H3S)}] 1 and the novel co-linear cluster [Os3(CO)11{μ3-η4-(C4H3S)C2C2(C4H3S)}] 2 in reasonable yield; the X-ray structure of 2 shows that the diyne is coordinated to an ‘open’ triosmium unit as a 1,2,3-triene-1,4-diyl unit with essentially equal CC bond distances.

The cyclic voltammograms of the alkyne complexes [M(SR)L(eta-R'C[triple bond, length as m-dash]CR')(eta-C(5)H(5))] (M = Mo or W, R = Me or Ph, R' = Me or Ph) show two oxidation processes. Both are irreversible for the stereochemically rigid carbonyls (L = CO) but the first is reversible for the fluxional phosphites {L = P(OMe)(3)}; the paramagnetic monocations [M(SPh){P(OMe)(3)}(eta-MeC[triple bond, length as m-dash]CMe)(eta-C(5)H(5))](+) were detected by ESR spectroscopy after in situ chemical one-electron oxidation. By contrast, the hydrotris(pyrazolyl)borate analogues [W(SR)(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'] {R = Me or Ph, Tp' = hydrotris(3,5-dimethylpyrazolyl)borate} are oxidised in two reversible steps to the corresponding mono- and dications; the redox pair [W(SPh)(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'](z) (z = 0 and 1+) has been structurally characterised. A comparison of the redox potentials for the oxidation of [W(SR)(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'] with those of the halide analogues [WX(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'] suggests that the factors which give rise to the inverse halide order for the latter may not operate for the thiolates, which appear to be the better pi-donors in all three redox states [WL(CO)(eta-PhC[triple bond, length as m-dash]CPh)Tp'](z) (L = halide or thiolate, z = 0, 1+ and 2+).

The synthesis and subsequent photophysical investigation of [Pt(mesBIAN)(tda)], where mesBIAN is bis(mesitylimino)acenaphthene and tda is tolan-2,2'-diacetylide, reveal excited-state characteristics best described as triplet charge transfer ((3)CT) in nature upon visible light excitation. Large ground-state dipole moments are apparent as the absorption spectrum dramatically red-shifts with decreasing solvent polarity. The (3)CT excited state is significantly lower in energy than the ligand-centered (3)tda excited-state, as confirmed by steady-state and time-resolved techniques. Singlet oxygen sensitization studies demonstrate that (1)O(2) production occurs by diffusive quenching from the photo-excited (3)CT state (Phi(Delta) = 0.24, lambda(max) approximately 1270 nm) in oxygen-saturated dichloromethane.

The complexes [(eta-C(5)Me(5))(ON)LMn(micro-CN)M(CO)(RC[triple bond, length as m-dash]CR)Tp'](+) (L = CNXyl, M = Mo; L = CNBu(t), M = Mo or W, R = Ph or Me) and trans- or cis-[(dppm){(EtO)(3)P}(OC)(2)Mn(micro-CN)M(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+), and their linkage isomers [(eta-C(5)Me(5))(ON)LMn(micro-NC)M(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+) and trans- or cis-[(dppm){(EtO)(3)P}(OC)(2)Mn(micro-NC)M(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+), undergo two one-electron oxidations. The complexes [(eta-C(5)Me(5))(ON)LMn(micro-XY)M(CO)(RC[triple bond, length as m-dash]CR)Tp'](+) (XY = CN or NC) are oxidised first at the N-bound metal centre and then at the C-bound centre. For [(dppm){(EtO)(3)P}(OC)(2)Mn(micro-XY)M(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+), the trans isomers are first oxidised at manganese whereas the cis isomers are first oxidised at M. Thus, the order of one-electron oxidation of the two series of binuclear monocations is influenced by linkage isomerisation of the cyanide bridge and cis-trans isomerisation of the Mn(CO)(2) group. IR spectroscopic changes on reaction of Ag(+) with [(eta-C(5)Me(5))(ON)(Bu(t)NC)Mn(micro-CN)W(CO)(MeC[triple bond, length as m-dash]CMe)Tp'](+) are consistent with one-electron at the N-bound tungsten centre. Likewise, trans-[(dppm){(EtO)(3)P}(OC)(2)Mn(micro-NC)M(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+) (M = Mo or W) give the stable dications [(dppm){(EtO)(3)P}(OC)(2)Mn(micro-NC)M(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](2+). Significantly longer Mn-P bond distances in trans-[(dppm){(EtO)(3)P}(OC)(2)Mn(micro-NC)Mo(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](2+) than in trans-[(dppm){(EtO)(3)P}(OC)(2)Mn(micro-NC)Mo(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+) are consistent with one-electron oxidation first at Mn(I); the alignment of the (CN)Mn(CO)(2){P(OEt)(3)}(dppm) fragment relative to the alkyne in trans-[(dppm){(EtO)(3)P}(OC)(2)Mn(micro-NC)Mo(CO)(PhC[triple bond, length as m-dash]CPh)Tp'](+) suggests it acts as a pi-acceptor, in contrast to related species such as trans-(NC)Mn(CO)(2){P(OEt)(3)}(dppm) and (NC)Mn(NO){P(OPh)(3)}(pi-C(5)H(4)Me) which behave as simple N-donors.

Methylglyoxal in New Zealand manuka honey has been shown to originate from dihydroxyacetone, which is present in the nectar of manuka flowers in varying amounts. Manuka honey, which was freshly produced by bees, contained low levels of methylglyoxal and high levels of dihydroxyacetone. Storage of these honeys at 37 degrees C led to a decrease in the dihydroxyacetone content and a related increase in methylglyoxal. Addition of dihydroxyacetone to clover honey followed by incubation resulted in methylglyoxal levels similar to those found in manuka honey. Nectar washed from manuka flowers contained high levels of dihydroxyacetone and no detectable methylglyoxal.

The d4 halide complexes [MX(CO)(eta-RC[triple bond, length as m-dash]CR)Tp'] [R = Me, M = W, X = F; R = Ph, M = Mo or W, X = F or Cl; Tp' = hydrotris(3,5-dimethylpyrazolyl)borate] undergo two-electron oxidation in the presence of a halide source to give the d2 monocations [MX1X2(eta-PhC[triple bond, length as m-dash]CPh)Tp']+ (R = Me, M = W, X1 = X2 = F; R = Ph, M = Mo, X1 = X2 = F or Cl; M = W, X1 = X2 = F or Cl; X1 = F, X2 = Cl). Each monocation (R = Ph) shows two reversible one-electron reductions (the second process was not detected for R = Me) corresponding to the stepwise formation of the neutral d3 and monoanionic d4 analogues, [MX1X2(eta-PhC[triple bond, length as m-dash]CPh)Tp'] and [MX1X2(eta-PhC[triple bond, length as m-dash]CPh)Tp']- respectively; the potentials for the two processes can be 'tuned' over a range of ca. 1.0 V by varying M and X. Chemical one-electron reduction of [MX2(eta-PhC[triple bond, length as m-dash]CPh)Tp']+ gave [MX2(eta-PhC[triple bond, length as m-dash]CPh)Tp'] (M = Mo or W, X = F or Cl). X-Ray structural studies on the redox pairs [WX2(eta-PhC[triple bond, length as m-dash]CPh)Tp']z (X = F and Cl, z = 0 and 1+) show the alkyne to bisect the X-W-X angle in the d2 cations but align more closely with one M-X bond in the neutral d3 molecules, consistent with the anisotropic ESR spectra of the latter; the solution ESR spectrum of [MoF2(eta-PhC[triple bond, length as m-dash]CPh)Tp'] showed equivalent fluorine atoms, i.e the alkyne oscillates at room temperature. The successful isolation of [MX2(eta-PhC[triple bond, length as m-dash]CPh)Tp']+ and [MX2(eta-PhC[triple bond, length as m-dash]CPh)Tp'] completes a series in which d6 to d2 alkyne complexes are linked in a redox family tree by sequential one-electron transfer and substitution reactions. The implications for such trees in the production of new species and the selective synthesis of paramagnetic complexes acting as synthetically useful 'alkyne radicals' are discussed.

2′-Hydroxy-6′-methoxychalcone epoxide reacts in neutral aqueous acetonitrile solution to give a 6:1 ratio of the α- and β-cyclisation products, erythro -4-methoxyaurone hydrate [ erythro -2-(α-hydroxybenzyl)-4-methoxycoumaran-3-one] and trans -3-hydroxy-5-methoxyflavanone: the dominance of α-cyclisation may be associated with a stereoelectronic preference for a conformation favourable for α- but not β-cyclisation when the carbonyl group is forced by the 6′-substituent to lie out-of-plane with the aromatic ring. In more basic solutions, erythro - threo isomerisation of aurone hydrate occurs, and 4-methoxycoumaran-3-one and 4-methoxyaurone are formed. Other 6′-substituted 2′-hydroxychalcone epoxides show a similar strong preference for α- over β-cyclisation.

Various preparations of some 2′-tetrahydropyren-2-yloxychalcone epoxides and removal of their tetrehydropyranyl (THP) protective groups in slightly aqueous acidic dioxane are described. So synthesised were 2′-hydroxy-6′-isopropoxy- and 2′-hydroxy-6′-methoxychalcone epoxide, as well as the 2-CF3, 4-Cl and 4-NO2 analogues of the latter, 2′,4′-dihydioxy-6′-methoxychalcone epoxide was similarly prepared. In some other 6−'methoxy cases protective group removal was accompanied by epoxide solvolysis and the corresponding α,β-dihydroxydihydrochalcone was the only isolable product [2-OMe, 4-OMe, 3,4,5-(OMe)3 cases] or a byproduct [4-Me case]. Similarly prepared by THP removal were 2′-hydroxy-4′-methoxychalcone epoxide and 2′,4′-dihydioxychalcone epoxide, whereas an attempt to convert 2′,6′-ditetrahydropyranyloxychalcone epoxide into 2′,6′-dihydroxychalcone epoxide gave the product of cyclisation of the latter, 3,5-dihydroxyflavanone.

The compounds [Pt(MesBIAN)(C[triple bond]CR)2] (R = C6H4-CN-p, 1; SiMe3, 2; C6H4-CF3-p, 3; C6H5, 4; C6H4-CH3-p 5) {MesBIAN = bis(mesitylimino)acenaphthene} have been synthesized; the X-ray crystal structure determinations of 4 and 5 and the starting material [Pt(MesBIAN)Cl2] are reported. Chemical oxidation of 4 with diiodine leads to generation of an intermediate platinum(IV) bis(acetylide) diiodide complex, which then couples and reductively eliminates the acetylide ligands as a diyne, leading to the generation of [Pt(MesBIAN)I2] 6. Compound 2 readily forms an adduct 2a with copper(I) chloride, in which the copper atom is bonded to the two acetylide triple bonds. 1-5 each undergo an irreversible oxidation, and a reversible one-electron reduction to generate a stable anion. ESR studies of 1(-)-5(-) show that the unpaired electron is localized mainly on the pi* orbital of the coordinated MesBIAN ligand, with about 10% platinum contribution to the singly occupied molecular orbital (SOMO). The compounds show a strong absorption at around 500 nm in the UV/visible spectrum, which is assigned to a "mixed metal-ligand to ligand charge transfer" (MMLL'CT) transition; this assignment is supported by time-dependent density-functional theory (TD-DFT) calculations on 5. 1-5 emit in the near-infrared region from a (3)MMLL'CT excited state, with lifetimes ranging from 8 to 36 ns. Picosecond and nanosecond time-resolved infrared (TRIR) spectroscopy has been used to probe directly the nature and dynamics of the excited state of 5. The TRIR data show a decrease of the energy of the C[triple bond]C vibration upon excitation, by about 90 cm(-1) in comparison to the ground state, and formation of a new, very intense, and very broad band at 1820 cm(-1). We propose that the excited-state structure contains some contribution from a pseudo-cumulenic form of the platinum-acetylide moiety, which is supported by TD-DFT calculations. Picosecond TRIR allowed determination of the rate of vibrational relaxation (14 ps) of the vibrationally "hot" electronic excited state of 5 formed upon initial laser excitation.

The structures adopted by a range of poly(pyrazolyl)borate complexes [ML2Tp(x)] [M = Rh, Ir; L2 = diene; Tp(x) = Bp' {dihydrobis(3,5-dimethylpyrazolyl)borate}, Tp' {hydrotris(3,5-dimethylpyrazolyl)borate}, Tp {hydrotris(pyrazolyl)borate}, B(pz)4 {tetrakis(pyrazolyl)borate}] have been investigated. Low steric hindrance between ligands in [Rh(eta-nbd)Tp] (nbd = norbornadiene), [Rh(eta-cod)Tp] (cod = cycloocta-1,5-diene) and [Rh(eta-nbd)Tp'] results in K3 coordination of the pyrazolylborate but [M(eta-cod)Tp'] (M = Rh, Ir) are kappa2 coordinated with the free pyrazolyl ring positioned above and approximately parallel to the square plane about the metal. All but the most sterically hindered Tp(x) complexes undergo fast exchange of the coordinated and uncoordinated pyrazolyl rings on the NMR spectroscopic timescale. For [Rh(eta-cod){B(pz)4}], [Rh(eta-dmbd)Tp'] (dmbd = 2,3-dimethylbuta-1,3-diene) and [Rh(eta-cod)Tp(Ph)] {Tp(Ph) = hydrotris(3-phenylpyrazolyl)borate} the fluxional process is slowed at low temperatures so that inequivalent pyrazolyl rings are observed. The bonding modes of the Tp' ligand (but not of other pyrazolylborate ligands) can be determined by 11B NMR and IR spectroscopy. The 11B chemical shifts (for a series of Tp' complexes) show the general pattern, kappa3-7.5 ppmkappa2 and the nu(BH) stretch kappa32500 cm(-1)kappa2. The electrochemical behaviour of the pyrazolylborate complexes is related to the degree of structural change which occurs on electron transfer. One-electron oxidation of complexes with Tp', Tp and B(pz)4 ligands is generally reversible although that of [Ir(etacod)Tp] is only reversible at higher scan rates and that of [Ir(eta-cod){B(pz)4}] is irreversible. Of the complexes with the more sterically hindered Tp(Ph) ligand, only [Rh(eta-nbd)Tp(Ph)] shows any degree of reversible oxidation. The ESR spectra of a range of Rh(II) complexes show coupling to both 14N and 103Rh nuclei in most cases but what appears to be coupling to rhodium and one hydrogen atom, possibly a hydride ligand, for the oxidation product of [Rh(eta-nbd)Tp(Ph)].

An optimized procedure for the selective dimetalation of [V(eta (6)-C 6H 6) 2] by BuLi/tmeda allowed for the isolation and characterization of [V(eta (6)-C 6H 5Li) 2].tmeda. X-ray diffraction of its thf solvate [V(eta (6)-C 6H 5Li) 2].(thf) 7 revealed an unsymmetrical, dimeric composition in the solid state, in which both subunits are connected by three bridging lithium atoms. Treatment with several element dihalides facilitated the isolation of [ n]vanadoarenophanes ( n = 1, 2) with boron and silicon in the bridging positions. In agreement with the number and covalent radii of the bridging elements, these derivatives exhibit molecular ring strain to a greater or lesser extent. The B-B bond of the [2]bora species [V(eta (6)-C 6H 5) 2B 2(NMe 2) 2] was readily cleaved by [Pt(PEt 3) 3] to afford the corresponding oxidative addition product. Subsequently, [V(eta (6)-C 6H 5) 2B 2(NMe 2) 2] was employed as a diborane(4) precursor in the diboration of 2-butyne under stoichiometric, homogeneous, and heterogeneous catalysis conditions. This transformation is facilitated by the reduction of molecular ring strain, which was confirmed by a decrease of the tilt angle alpha observed in the corresponding solid-state structures. EPR spectroscopy was used to probe the electronic structure of strained [ n]vanadoarenophanes and revealed an obvious correlation between the degree of molecular distortion and the observed hyperfine coupling constant a iso. State-of-the-art DFT calculations were able to reproduce the measured isotropic vanadium hyperfine couplings and the coupling anisotropies. The calculations confirmed the decrease of the absolute isotropic hyperfine couplings with increasing tilt angle. Closer analysis showed that this is mainly due to increased positive contributions to the spin density at the vanadium nucleus from the spin polarization of doubly occupied valence orbitals of vanadium-ligand sigma-antibonding character. The latter are destabilized and thus made more polarizable in the bent structures.

U-Pb ages of detrital zircons from greywacke, and Rb-Sr metamorphic ages of slate from the Puncoviscana Formation of northwest Argentina are reported, and used to constrain the depositional age, metamorphic history, and sedimentary provenance of these rocks. The detrital zircon ages define mainly Late Mesoproterozoic-Early Neoproterozoic (1150-850 Ma) and Late Neoproterozoic-Early Cambrian (650-520 Ma) populations, the relative proportions of which vary inversely with the age of the youngest zircons in the samples. The 1150-850 Ma population is present in all samples and dominates in those with relatively old grains (> 600 Ma) in the Late Neoproterozoic-Early Cambrian population. However, the Late Mesoproterozoic-Early Neoproterozoic population is substantially smaller in those samples in which the Late Neoproterozoic-Early Cambrian population dominates and contains relatively young grains (> 520 Ma). The youngest zircons, c. 520 Ma, are in the Rancagua (Cachi, Salta province) sample. They form a narrow, unimodal peak and may have originated from volcanic sources active during deposition, in which case these youngest zircons would constrain the depositional age of the sample to the late Early Cambrian. This is consistent with Rb-Sr ages of 550-500 Ma for samples of slate from the Puncoviscana Formation. The detrital zircon age populations suggest a sedimentary provenance in a continental hinterland with a stabilized, extensive Late Mesoproterozoic orogen (with minor Paleoproterozoic and Archean precursors) and a more variable Late Neoproterozoic orogen containing an evolving sequence of less extensive subcomponents. A direct relationship with the Brazilian Shield is thus suggested with sedimentary detritus originating within the active-margin orogens of the interior, but with ultimate deposition in the passive-margin environment of western Gondwanaland. ©2008 E. Schweizerbart'sche Verlagsbuchhandlung. Fil: Adams, Christopher J.. Lower Hutt; Nueva Zelanda Fil: Miller, Hubert. Technische Universitat München; Alemania Fil: Toselli, Alejandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Correlación Geológica. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Departamento de Geología. Cátedra Geología Estructural. Instituto Superior de Correlación Geológica; Argentina Fil: Griffin, William F. Macquarie University; Australia

Using HPLC a fraction of New Zealand manuka honey has been isolated, which gives rise to the non-peroxide antibacterial activity. This fraction proved to be methylglyoxal, a highly reactive precursor in the formation of advanced glycation endproducts (AGEs). Methylglyoxal concentrations in 49 manuka and 34 non-manuka honey samples were determined using a direct detection method and compared with values obtained using standard o-phenylenediamine derivatisation. Concentrations obtained using both the methods were similar and varied from 38 to 828 mg/kg.

The triazenide-bridged tetracarbonyls [(OC)(2)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)M(CO)(2)] (M = Rh or Ir) undergo oxidative addition of iodine across the dimetal centre, giving the [RhM](4+) complexes [I(OC)(2)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)M(CO)(2)I], structurally characterised for M = Ir. The anionic tricarbonyl iodide [I(OC)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)Rh(CO)(2)](-) forms [I(2)(OC)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)Rh(CO)I](-) by initial one-electron transfer whereas the analogous tricarbonyl phosphine complexes [(OC)(Ph(3)P)Rh(mu-p-MeC(6)H(4)NNNC(6)H(4)Me-p)(2)M(CO)(2)] (M = Rh or Ir) undergo bridge cleavage, giving mononuclear [Rh(p-MeC(6)H(4)NNNC(6)H(4)Me-p)I(2)(CO)(PPh(3))] and dimeric [I(OC){RNNN(R)C(O)}M(mu-I)(2)M{C(O)N(R)NNR}(CO)I] (M = Rh or Ir, R = C(6)H(4)Me-p) in which CO has been inserted into a metal-nitrogen bond.

The coordination chemistry of the tetradentate pyridyl-thiazole (py-tz) N-donor ligand 6,6'-bis(4-phenylthiazol-2-yl)-2,2'-bipyridine (L1) has been investigated. Reaction of L1 with equimolar copper(II) ions results in the formation of the single-stranded mononuclear complex [Cu(L1)(ClO4)2] (1), whereas reaction with copper(I) ions results in the double-stranded dinuclear helicate [Cu2(L1)2][PF6]2 (2). Both complexes were characterized by X-ray crystallography, UV-vis spectroscopy, and electrospray ionization mass spectroscopy (as well as 1H NMR spectroscopy for diamagnetic 2). Complex 2 is redox-active and, upon one-electron oxidation, forms the stable tricationic mixed-valence helicate [Cu2(L1)2]3+ (3). This species can also be prepared in situ by combining [Cu(MeCN)4][BF4], [Cu(H2O)6][BF4]2, and L1 in a 1:1:2 ratio in nitromethane. X-ray crystallographic analysis of 3 provides structural evidence for the presence of an internuclear Cu-Cu bond, with an even distribution of spin density across the two Cu centers. Room-temperature UV-vis spectroscopy is consistent with this finding; however, frozen-glass EPR spectroscopic investigations suggest solvatochromic behavior at 110 K, with the [Cu2]3+ core varying from localized to delocalized depending on the solvent polarity.