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The synthesis and X-ray crystal structure of acetatobis( l -arginine)zinc(II) acetate trihydrate, [Zn(OAc)( l -Arg)2]OAc·3H2O is reported. In this structure, the first of a zinc(II)–arginine complex to be reported, the geometry around zinc(II) is distorted square-pyramidal containing two trans-N,O chelated l -Arg ligands in the basal plane and the acetato ligand in an axial position. The structure contains a second acetate which is salt-bridged to the δ and ω NH groups of the guanidinium side chain of an arginine ligand and also contains three hydrogen bonded water molecules.

The electrochemical synthesis of Sc(OMe)3 (1), Sc(OEt)3 (2) and Sc5O(OPri)13 (3) was carried out via anodic oxidation of scandium metal in aliphatic alcohols. X-ray single crystal study showed 3 to be analogous to the known isopropoxides of Y, Er, Yb and In. The interaction of 3 with excess ROH (R=Me, Et, Bun, Bus, But) gives non-volatile amorphous 1, 2 and Sc(OBun)3 (4), and volatile Sc5O(OBus)13 (5) and Sc5O(OPri)8(OBut)5 (6). Oxoalkoxides Sc5O(OPri)8(OR)5 (R=Bun 7, Me 8) were obtained on reaction of 3 with n-ROH in 1:5 ratio. The mass spectral study shows 5 is an individual compound, whereas 6–8 in the gas phase consist of a number of aggregates with different extents of substitution for OPri groups, Sc5O(OR)n(OPri)13−n: for R=But n≤5, for R=Bun n≤8, and for R=Me n≤12. The maximal intensity in the spectrum of 6 is observed for Sc5O(OPri)10(OBut)2+, and in the spectra of 7 and 8 for Sc5O(OPri)12−n(OBun)n+, n=4, 5, and Sc5O(OPri)9(OMe)3+ respectively. The presence of the Sc5O(OMe)12+ ion in the spectrum of 8 indicates the possibility of replacing all the OPri in the pentanuclear core and demonstrates the existence of a ‘volatile scandium methoxide’ in the gas phase. Study of the complex formation of Sc(OR)3 with Al(OR)3 has shown that 2 and 4 form volatile Sc[Al(OR)4]3, R=Et 9, Bun 10, while 3 does not react under these conditions. Sc[Al(OPri)4]3 (11) can be obtained only on exchange reaction of ScCl3 with KAl(OPri)4. The results obtained indicate rather high stability of the [Sc5O(OR)8] core for primary and secondary R.

The thermal reaction of nBuOCH=CHPEt2 with Os3(CO)12 gives a new osmium triangular cluster, Os3(μ-H)(μ3-nBuOC=CHPEt2)(CO)9 (1), which was isolated in 62% yield. The structure of 1 has been determined by X-ray diffraction ( P 1 ¯ , a = 12.914(3), b = 13.984(4), c = 16.375(4) A, α = 66.83(2), β = 77.82(2), γ = 77.97(2)°, Z = 4, dcalc = 2.552 g/cm3, R = 0.0399 for 6636 reflections). The μ3-nBuOC=CHPEt2 in 1 acts as a five-electron donor. It forms a σ-bond with one Os atom and coordinates the second and the third Os atoms of the cluster by its olefinic bond and the phosphorus atom, respectively. Both complex 1 and Os3(μ-H)(μ-CH=CHR)(CO)10 (R=nC6H13, Ph) catalyze the silylation of terminal olefins with Et3SiH to yield the corresponding trans-triethylvinylsilanes and alkanes in moderate yield even at ambient temperature. The proposed mechanism of olefin silylation catalyzed by triangular metal clusters involves the olefin C−H bond activation on the triangular cluster core and formation of an intermediate which has a structure similar to that of cluster 1.

The dimers {(tBuC5H4)2,Ln(μ-Me)}2 (LnY, or Lu) react with organic dichalcogenides R2E2 (ES or Se; RPh, nBu, tBu or CH2Ph) to form {(tBuC5H4)2Ln(μ-ER)}2 complexes with LnS or LnSe bonds. The molecular structure of {(tBuC5H4)2Ln(μ-SePh)}2·C6H6 has been determined by X-ray diffraction (P; a = 11.242(2) A, b = 11.388(2) A and c = 12.865(2) A; α = 110.32(2)°; β = 105.16(2)°; and γ = 102.84(2)°; Z = 1; dcalc. = 1.343 g cm−3; R = 0.0509 and Rω = 0.0532). The two yttrium atoms of the centrosymmetric dimeric molecule are bridged by two μ-SePh groups.

Reactions of the [K]+ salts of the [nido-7,9-C2B9H12]- anion (2) and its C-phenylated derivative [7-Ph-nido-7,9-C2B9H11]- (4) with [OsCl2(PPh3)3] (3) proceed in benzene at ambient temperature with the formation of 16-electron chlorohydrido-Os(IV) exo-nido complexes, [exo-nido-10,11-{(Ph3P)2OsHCl}-10,11-(mu-H)2-7-R-7,9-C2B9H8] (5: R = H; 6: R = Ph), along with the small amounts of the charge-compensated nido-carboranes [nido-7,9-C2B9H11PPh3] (7) and [7-Ph-nido-7,9-C2B9H10PPh3] (8) as byproducts. However, when carried out under mild heating in ethanol, the reaction of 2 with 3 selectively afforded a 16-electron dihydrido-Os(IV) exo-nido complex [exo-nido-10,11-{(Ph3P)2OsH2}-10,11-(mu-H)2-7,9-C2B9H9] (9). Structures of both complexes 5 and 9 have been confirmed by single-crystal X-ray diffraction studies, which revealed that nido-carboranes in these species function as a bidentate dicarbollide ligands [7-R-nido-7,9-C2B9H10]2- linked to the Os(IV) center via two B-H...Os bonds involving adjacent B-H vertices in the upper CBCBB belt of the carborane cage. Thus, compounds 5 and 9 represent the first structurally characterized exo-nido-metallacarboranes based on meta-dicarbollide-type ligands. Variable-temperature 1H and 31P{1H} NMR experiments indicate that complex 9 is fluxional in solution and shows an unusual exchange between terminal Os-(H)2 and bridging {B-H}2...Os hydrogen atoms. Upon heating in d8-THF at 65 degrees C, complex 9 converts irreversibly to its closo isomer [2,2-(PPh3)2-2,2-H2-closo-2,1,7-OsC2B9H11] (13), which could thus be obtained as a pure crystalline solid. The structure of 13 has been established on the basis of analytical and multinuclear NMR data and a single-crystal X-ray diffraction study.

The organogermanium complex of ytterbium [(Ph2Ge)4Yb(THF)4]·4THF (1) was synthesized by the reaction of metallic ytterbium with Ph2GeCl2 in THF at room temperature. X-ray study has shown that the molecule of (Ph2Ge)4Yb(THF)4 is an octahedral Yb complex with the C2 symmetry. The four coordination positions at the Yb atom are occupied by the oxygen atoms of THF molecules and the two cis-positions are occupied by two terminal germanium atoms of the P Ph2GeGePh2GePh2GePh2 fragment. Thus, the (Ph2Ge)4Yb(THF)4 molecule involves the five-membered Ge4Yb metallocycle with a twist conformation. The YbGe and YbO distances are 3.104(2) and 2.475(8), 2.402(10) A.

The hexanuclear complex of calcium oxo ethoxide ethanol solvate, [Ca6O2(OEt)8]·14EtOH 1 has been isolated after the prolonged refluxing of an ethanol solution of calcium ethoxide in the presence of the oxygen in air and studied by X-ray diffraction; the metal-oxygen framework is built of two [Ca4O4] cubes sharing a common [Ca2O2] face, which involves both oxo groups.

Reaction of [{Cp*RhCI2}2] (Cp*=η5-C5Me5) with the PPN (PPN+ = Ph3P=N=PPh3+) salts of iso- and heteropolymolybdates offers a good route to polyoxometallates containing organometallics; the syntheses and X-ray structures of [(Cp*Rh)4(Mo4O16)], containing a tris-cubane oxotetramolybdenum skeleton (derived from (PPN)2[MoO4]-6H2O) and the ionic [Cp*RhCl3RhCp*]+[PPN]+2[PMo12O40]3− (derived from (PPN)2[Mo2O7]) are described.