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New tertiary ferrocenyl stibines (I and III) and bismuthine (II) have been synthesized. All these compounds have been characterized by IR, MS, and NMR spectroscopy and the molecular structures of I–III have been determined by X-ray crystallography. Compounds I–III have also been studied by cyclic voltammetry (CV). Crystal structures of homoleptic stibine and bismuthine (I, II) adopt a "propeller" configuration with the three ferrocenyl groups tilted to minimize interatomic repulsion and exhibit helicoidal chirality. The structures of I and III show that both the stibines exhibit an intramolecular C−H···C interaction. The voltammograms of stibines show that E1/2 values are more positive than that of ferrocene indicating that oxidation of Fc3Sb is slightly more challenging in comparison to ferrocene. Triferrocenyl bismuthine (II) displays two redox waves with low resolution and a non-reversible process. [ABSTRACT FROM AUTHOR]

• Efficient combination of SiO 2 /Al 2 O 3 /SnO 2 ternary oxide and FIA – HG AAS for antinomy determination was observed. • Proposed method provided high preconcentration factor (136-fold) and low limit of detection (0.17 μg L−1) for Sb(III). • High stability of adsorbent (390 preconcentration/elution cycles without losses of sorption capacity) was achieved. In the present paper, a new analytical preconcentration/speciation method for antimony species determination in bottled mineral water samples using the SiO 2 /Al 2 O 3 /SnO 2 adsorbent was developed. The method is based on selective adsorption of Sb(III) ions by SiO 2 /Al 2 O 3 /SnO 2 under a wide pH range (2.5–7.5). Total antimony was determined with previous sample treatment using 0.1% (w/v) l -cysteine and the concentration of Sb(V) species was determined by the difference between total and Sb(III). The proposed method provided an analytical curve ranging from 0.50 to 5.00 μg L−1 (r = 0.999), limit of detection (LD) of 0.17 µg L−1 and preconcentration factor (PF) of 136-fold. The method exhibited tolerance to different metal ions and the accuracy was attested from addition and recovery tests (95.2–106.0%) in bottled mineral water samples using 2.0% (w/v) l -cysteine, as well as by analysis of certified material. Only Sb(III) species were determined in mineral water (0.54–1.04 μg L−1). [ABSTRACT FROM AUTHOR]

In this study, we describe the synthesis and characterization of dimeric tetrathiafulvalene (TTF) derivatives that are doubly bridged by Sn (1) and Sb (2a) atoms as a new class of organic‐inorganic hybrid compounds able to provide enhanced dimensionality in the solid state. The antimony heterocyclic framework was constructed by a simple Sn–Sb metal exchange reaction of a 1,4‐distannine moiety with p‐tolyl antimony dichloride (p‐tolSbCl2). Compound 2a was obtained in cis and trans forms as a stable configurational isomer. From X‐ray crystallographic analysis, there were three conformational isomers in which the tolyl rings were directed in the endo or exo direction. Crystal packing revealed a supramolecular three‐dimensional network through intermolecular short contacts of Sb···S and Sb···π. These packing forces gave a trans‐2aexo–exo conformation in the crystal, although the theoretical calculations predict its instability compared with other conformers. Cyclic voltammetry (CV) measurements of 1 and cis/trans‐2a revealed two pairs of reversible redox processes corresponding to the formation of TTF/TTF·+ and TTF·+/TTF2+. Furthermore, CV of cis/trans‐2a also revealed the reduction waves derived from the reduction of SbIII. Dicationic and tetracationic species were prepared by chemical oxidation, and their electronic structures were also investigated by electronic spectroscopy. [ABSTRACT FROM AUTHOR]

Our interest in bifunctional antimony Lewis acids has led us to synthesize 1,8-bis(diphenylstibino)biphenylene (2) by reaction of 1,8-bis(trimethylstannyl)biphenylene (1) with Ph2SbCl. Oxidation of this distibine with o-chloranil, followed by work-up in air afforded a biphenylene derivative (3) featuring a triarylstibine oxide connected via an Sb=O → Sb bridge to the neighbouring antimony(v) center. [ABSTRACT FROM AUTHOR]

The metallostibine Os 2 (CO) 8 ( μ -SbPh), 2 , acts as a good two-electron donor ligand, reacting readily with Group 8 metal carbonyls to give heterometallic clusters. Specifically, it undergoes ligand substitution reaction with Fe 2 (CO) 9 , Os 3 (CO) 11 (CH 3 CN), or Os 3 (CO) 10 (CH 3 CN) 2 to afford Os 2 Fe(CO) 12 ( μ 3 -SbPh), 3 , Os 5 (CO) 19 ( μ 3 -SbPh), 4 , or Os 7 (CO) 26 ( μ 3 -SbPh) 2 , 5 , respectively, in moderate to high yields. An analogous reaction with Ru 3 (CO) 11 (CH 3 CN) afforded another spirocyclic cluster Os 3 Ru(CO) 14 ( μ -PhCO)( μ 4 -Sb), 9 . UV irradiation of 4 afforded the spirocyclic clusters Os 5 (CO) 18 ( μ , η 2 -PhCO)( μ 4 -Sb), 6 , and Os 5 (CO) 18 ( μ , η 2 -C 6 H 4 )( μ -H)( μ 4 -Sb), 7 , while the raft-like cluster Os 5 (CO) 19 ( μ 3 -SbPh), 8 , was obtained when a methanolic solution was exposed to natural light; cluster 5 failed to react under similar conditions. All the new clusters have been characterized spectroscopically and crystallographically, and possible pathways for the formation of 6 - 9 proposed. [ABSTRACT FROM AUTHOR]

A series of new cationic Rn-substituted-indenyl nickel(II) complexes containing arsine or stibine ligands were synthesized in moderate to very high yields by the protonation of the corresponding bis(indenyl) nickel derivatives [Ni(η-Rn- Ind)2] with HBF4, in the presence of 2 equiv. of AsPh3 or SbPh3 donor ligands. These complexes, with the general formula [Ni(η- Rn-Ind)(EPh3)2]BF4 (E = As, Sb), were structurally characterized by NMR spectroscopy and X-ray diffraction, and subsequently tested as single-component catalysts for the oligomerization of styrene, leading to the formation of very low molecular weight head-to-tail oligomers (typically consisting of dimers, trimers and tetramers). The new 1- or 2-monosubstituted-indenyl NiII catalyst precursors exhibit extremely high catalytic activities, considerably higher than those observed for the symmetrical unsubstituted- and the 1,3-disubstituted-indenyl nickel analogues (i.e. monosubstituted >> non-substituted > 1,3-disubstituted), their reactivity pattern showing similarities with that of the corresponding allyl derivatives. A simpler and more straightforward experimental procedure for the high yield preparation of [NiBr2(DME)], an important nickel starting material, which was used in the preparation of the bis(indenyl) nickel precursors of this work, is also described. [ABSTRACT FROM AUTHOR]

Open and closed type triiron chalcogenide stibine cluster molecules have been synthesized and characterized by single crystal X-ray structural studies. A comparison between the phenyl and isopropyl analogues of the open cluster compound shows some unique decarbonylation tendency for the phenyl analogue which easily converts an open cluster to a closed cluster molecule by a “butterfly wing-tip” opening mechanism. DFT study also revealed a critical behavior of such molecules in which the opening of a butterfly wing tip is governed by a decarbonylation step to give a closed cluster geometry. Antibacterial property was also studied with one of the closed cluster compound to understand their inhibition activity. [ABSTRACT FROM AUTHOR]

The pentavalent antimonies, mainly the meglumine antimoniate, are recommends as first-choice medicines for leishmaniasis therapy. In this work we described the development of formulations of meglumine antimoniate injectable medication, as well as the analytical methodology used in the selective determination of Sb(III) and Sb(Total) by hydride generation - inductively coupled plasma atomic emission spectrometry (HG-ICP-AES) and ICP-AES, respectively. On that purpose the analytical methodology was developed focusing on the HG-ICP-AES technique. The formulations using propylene glycol/water as vehicles in a 20:80 proportion were more appropriate for subsequent use in industrial scale. These formulations also showed a lower variation on Sb(III) percentage, no need of buffer solution to stabilize the formulation and no influence of the autoclaving in the quality of the product. The results of the development of the analytical methodology point out the proposed method as an efficient alternative for the determination of Sb(III) in the presence of large quantities of Sb(V) in injectable solutions of meglumine antimoniate, in a selective, linear, accurate and precise manner. In addition, the method showed a low limit of quantification, less interference of the matrix, and more resilience than batch techniques proposed in the Brazilian Pharmacopeia.

One-electron oxidation of the stibines Aryl3Sb ( 1, Aryl=2,6- iPr2-4-OMe-C6H2; 2, Aryl=2,4,6- iPr3-C6H2) with AgSbF6 and NaBArylF4 (ArylF=3,5-(CF3)2C6H3) afforded the first structurally characterized examples of antimony-centered radical cations 1.+[BArylF4]− and 2.+[BArylF4]−. Their molecular and electronic structures were investigated by single-crystal X-ray diffraction, electron paramagnetic resonance spectroscopy (EPR) and UV/Vis absorption spectroscopy, in conjunction with theoretical calculations. Moreover, their reactivity was investigated. The reaction of 2.+[BArylF4]− and p-benzoquinone afforded a dinuclear antimony dication salt 32+[BArylF4]2−, which was characterized by NMR spectroscopy and X-ray diffraction analysis. The formation of the dication 32+ further confirms that the isolated stibine radical cations are antimony-centered. [ABSTRACT FROM AUTHOR]

The reactions of 5-azido-3-methyl-1-phenyl-1 H-pyrazole-4-carbaldehyde (azidopyrazole) with several classes of organophosphorus reagents: phosphonium ylides, Wittig-Horner reagents, dialkylphosphonates, trialkylphosphites, tris(dialkylamino)phosphanes, triphenylstibane, triphenylarsane, and Lawesson's reagent are reported. Structural reasoning for the new products was based on compatible analytical and spectral data. The cytotoxic activity of most of the new products was evaluated against human breast carcinoma cell line (MCF7) and human hepatocellular carcinoma cell line(HepG2). Certain tested compounds showed promising results. [ABSTRACT FROM AUTHOR]

A series of arsine- and stibine-ligated Schiff base palladacycles were synthesized by the reaction of μ-Cl-bridged Schiff base palladacycles [Pd(C6H4CH]NC6H2R)( μ-Cl)]2 (R = 2,4,6-trimethyl or 2,6-diisopropyl) with AsPh3 or SbPh3. The new arsine- and stibine-ligated palladacycles were fully characterized using 1H NMR, 13C NMR and infrared spectroscopies, high-resolution , elemental analysis and single-crystal X-ray diffraction. Further exploration of the catalytic application of the palladacycles for of aryl bromides with arylboronic acids was carried out. It was found that the new palladacycles are considerably active for these . Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the title compound, [SbBr(C10H7)2], the SbIII atom has a distorted trigonal–pyramidal coordination geometry and the planes of the two naphthalene ring systems make a dihedral angle of 80.26 (18)°. An intramolecular C—H...Br hydrogen bond forms an S(5) ring motif. In the crystal, weak C—H...Br interactions link the molecules into helical chains along the b-axis direction.

The syntheses of rhodium(III) and iridium(III) half-sandwich complexes containing tertiary arsine and stibine ligands of the form [Cp*M(L)Cl 2 ] (M = Rh, Ir; L = AsEt 3 , AsPh 3 , SbPh 3 ) are reported. These compounds represent infrequent examples of rhodium and iridium metal complexes bearing arsenic or antimony ligands. All new compounds were fully characterised using 1 H and 13 C NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction. DFT calculations show the formation of the complexes from (Cp*MCl 2 ) 2 and EPh 3 (E = P, As, Sb) to be highly exothermic, although the enthalpic driving force is decreasing in the expected sequence P > As > Sb. [ABSTRACT FROM AUTHOR]

The synthesis of the Lewis base stabilized monomeric parent compound of stibanylboranes, 'H2SbBH2', is reported. Through a salt metathesis route, the silyl-substituted compounds (Me3Si)2SbBH2⋅LB (LB=NMe3, NHCMe) were synthesized as representatives of derivatives with a SbB σ bond. Under very mild conditions, they could be transformed into the target compounds Me3N⋅H2BHSbBH2⋅NMe3 and H2SbBH2⋅NHCMe, respectively. The products were characterized by X-ray structure analysis, NMR spectroscopy, IR spectroscopy, and mass spectrometry. DFT calculations give further insight into the stability and bonding of these unique compounds. [ABSTRACT FROM AUTHOR]

New indenyl nickel(ii) complexes bearing arsine or stibine ligands synthesised by a new methodology exhibit very high catalytic activities for the oligomerisation of styrene. [ABSTRACT FROM AUTHOR]

This article reviews work up until mid-2014 on the synthesis and properties of transition metal complexes containing the heavier Group 15 Sb(III) and Bi(III) ligands, of general formula ER 3 (E = Sb or Bi, R = alkyl, aryl, etc. , and may include a pendant donor group such as amine or ether) and ER (3− n ) X n (E = Sb or Bi, R is an organic substituent such as alkyl, aryl, etc. , X is an electronegative substituent such as halide, n = 0–3) in which these ligands function as a donor to a transition metal fragment, while simultaneously participating as an acceptor to another electronegative group such as an anionic or metal-coordinated halide, or an amine, ether, etc ., leading to Sb/Bi centres bearing more than eight valence electrons (‘hypervalent’). The Lewis acid properties of the halostibines and halobismuthines, ER (3− n ) X n , are also reviewed. [ABSTRACT FROM AUTHOR]

The electrochemical generation of antimony volatile species (stibine) using Au and Ag mercury amalgamated cathodes is described. Compared with some other cathode materials commonly used for electrochemical hydride generation, performance of the amalgamated cathodes is substantially better in the following aspects: higher interference tolerance, higher erosion resistance and longer useful working time. Using the amalgamated cathodes, it could be shown that interferences from major constituents at high concentrations, especially from transition metals, affecting stibine generation are not as significant as they are using other cathode types in regards to sensitivity and useful working time. Results obtained using the Ag/Hg amalgamated cathode showed a slightly higher sensitivity than the corresponding results obtained using the Au/Hg cathode. The Au/Hg cathode, which to our knowledge has not previously been used to generate stibine, showed considerably longer useful working time than the Ag/Hg one. The optimum catholytes for electrolytic generation of stibine (SbH 3 ) from Sb(III) and Sb(V) using the Au/Hg electrode were aqueous solutions containing 0.5 mol L −1 H 2 SO 4 and 0.5 mol L −1 HCl, respectively. Under optimized conditions, using the Au/Hg cathode and comparing to aqueous standards calibration curves, detection limits (3 σ ) of 0.027 µg L −1 for Sb(III) and 0.056 µg L −1 for Sb(V), were obtained. To check accuracy a marine sediment reference material (PACS-2, NRC) was analyzed using a method purportedly developed for this task. Good agreement, 95% confidence, was found between the certified and the experimental values for Sb. The proposed method was also applied to the determination of Sb in aqueous solutions of marine sediments samples from Comuna de Bajo Alto Provincia de El Oro—Ecuador. Recoveries of five replicate determinations of these samples were in the range of 98–103% thus showing acceptable accuracy in the analysis of real samples. [ABSTRACT FROM AUTHOR]

In our efforts to investigate thecoordination noninnocent behaviorof transition-metal stibine complexes, we have prepared a series ofplatinum complexes bearing the tetradentate ligand (o-(Ph2P)C6H4)3Sb (L). Treatment of (Et2S)2PtCl2with Laffords the lantern complex (o-(Ph2P)C6H4)3SbCl)Pt(Cl)(1-Cl), which undergoes facile exchange with fluorideto form the fluorostiboranyl complex ((o-(Ph2P)C6H4)3SbF)Pt(Cl) (1-F). Starting from 1-Cl, anion exchange andabstraction reactions afford [((o-(Ph2P)C6H4)3Sb)Pt(CyNC)][SbF6]2, ([2][SbF6]2), [((o-(Ph2P)C6H4)3SbF)Pt(CyNC)][SbF6] ([3][SbF6]),and ((o-(Ph2P)C6H4)3SbF2)Pt(CyNC) (4), which arerelated by the formal stepwise coordination of two fluoride ligandsto the antimony center. Structural studies of this series show thatthe Sb–Pt bond lengthens upon sequential fluoride coordinationat the antimony center, consistent with the weakening of the Sb–Ptinteraction. Natural bond orbital (NBO) calculations performed atthe density functional theory (DFT) optimized geometries suggest thatthe Sb–Pt interactions become more polarized across the series,as part of a larger “spillover” of electron densityfrom the antimony center to platinum. QTAIM analyses of the DFT-derivedwave functions for this series corroborate the weakening of the Sb–Ptinteraction and suggest that the Sb–Pt bonding pair becomesincreasingly polarized toward platinum upon successive fluoride coordinationat the antimony center. [ABSTRACT FROM AUTHOR]

A series of phosphine-stibine and phosphine-stiborane peri-substituted acenaphthenes containing all permutations of pentavalent groups SbCl nPh4- n ( 5- 9), as well as trivalent groups SbCl2, Sb(R)Cl, and SbPh2 ( 2- 4, R=Ph, Mes), were synthesised and fully characterised by single crystal diffraction and multinuclear NMR spectroscopy. In addition, the bonding in these species was studied by DFT computational methods. The P-Sb dative interactions in both series range from strongly bonding to non-bonding as the Lewis acidity of the Sb acceptor is decreased. In the pentavalent antimony series, a significant change in the P-Sb distance is observed between SbClPh3 and SbCl2Ph2 derivatives 6 and 7, respectively, consistent with a change from a bonding to a non-bonding interaction in response to relatively small modification in Lewis acidity of the acceptor. In the SbIII series, two geometric forms are observed. The P-Sb bond length in the SbCl2 derivative 2 is as expected for a normal (rather than a dative) bond. Rather unexpectedly, the phosphine-stiborane complexes 5- 9 represent the first examples of the σ4P→σ6Sb structural motif. [ABSTRACT FROM AUTHOR]

In this work, a novel method for determining Sb and Bi based on the trapping of their covalent hydrides onto quartz reflectors coated with immobilized palladium nanoparticles (Pd NPs) followed by total reflection X-ray fluorescence (TXRF) analysis is proposed. Pd NPs were synthesized by chemical reduction of the metal precursor using a mixture of water:ethanol as mild reducing agent. Silanization using 3-mercaptopropyltrimethoxysilane (MPTMS) was performed for the immobilization of Pd NPs onto the quartz substrates. Volatile hydrides (stibine and bismuthine) generated by means of a continuous flow system were flushed onto the immobilized Pd NPs and retained by catalytic decomposition. As a result of the high catalytic activity of the nanostructured film, trapping can be performed at ambient temperature with good efficiency. Limits of detection (LODs) were 2.3 and 0.70 μg L − 1 for Sb and Bi, respectively. Enrichment factors of 534 and 192 were obtained for Sb and Bi, respectively. The new method was applied for the analysis of several matrices (milk, soil, sediment, cutaneous powder). Recoveries were in the range of 98.4–101% for both elements with a relative standard deviation of 2.5% (N = 5). [ABSTRACT FROM AUTHOR]

The reaction of a cyclic disilylated bromostibine with magnesium yields a rare example of a magnesium stibide that can be silylated with trimethylchlorosilane. Reaction of the thus-obtained trisilylated stibine with potassium tert-butoxide gives a potassium stibide in a clean reaction. Attempts to obtain an antimony-containing oligosilanide did not lead to the expected compound but to another potassium stibide, which presumably forms from the initially formed silanide by a 1,2-silyl shift. The synthetic potential of the obtained stibides to serve as building blocks could be shown by the preparation of stibylated zircono- and hafnocenes. [ABSTRACT FROM AUTHOR]

A series of new N-heterocyclic carbene palladium complexes bearing AsPh3 and SbPh3 functions PdCl2(IMes)(AsPh3) (1a), PdCl2(IMes)(SbPh3) (1b), PdCl2(IPr)(AsPh3) (1c), PdCl2(IPr)(SbPh3) (1d), PdCl2(SIMes)- (AsPh3) (2a), PdCl2(SIMes)(SbPh3) (2b), PdCl2(SIPr)(AsPh3) (2c), and PdCl2(SIPr)(SbPh3) (2d) (IMes = N,N'-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene; IPr = N,N'-bis-(2,6-di(iso-propyl)phenyl)imidazol- 2-ylidene; SIMes = N,N'-bis-(2,4,6-trimethylphenyl)imidazolidin-2-ylidene; SIPr = N,N'-bis-(2,6-di(isopropyl) phenyl)imidazolidin-2-ylidene) was synthesized and fully characterized by 1H NMR, 13C NMR, and FT-IR spectroscopy, elemental analysis and single-crystal X-ray crystallography. The catalytic potential of these arsine and stibine-stabilized carbene palladium complexes for Pd-mediated transformations was investigated with various substrates in the Hiyama cross-coupling reactions and Buchwald-Hartwig aminations. The results demonstrate that these complexes show high catalytic activity and good tolerance to various chemical functions. [ABSTRACT FROM AUTHOR]

According to the covalent bond classification (CBC) method, two-electron donors are defined as L-type ligands, one-electron donors as X-type ligands, and two-electron acceptors as Z-type ligands. These three ligand functions are usually associated to the nature of the ligating atom, with phosphine, alkyl, and borane groups being prototypical examples of L-, X- and Z-ligands, respectively. A new SbNi platform is reported in which the ligating Sb atom can assume all three CBC ligand functions. Using both experimental and computational data, it is shown that PhICl2 oxidation of ( o-(Ph2P)C6H4)3SbNi(PPh3) ( 1) into [( o-(Ph2P)C6H4)3ClSb]NiCl ( 2) is accompanied by a conversion of the stibine L-type ligand of 1 into a stiboranyl X-type ligand in 2. Furthermore, the reaction of 2 with the catecholate dianion in the presence of cyclohexyl isocyanide results in the formation of [( o-(Ph2P)C6H4)3( o-O2C6H4Sb)]Ni(CNCy) ( 4), a complex featuring a nickel atom coordinated by a Lewis acidic, Z-type, stiborane ligand. [ABSTRACT FROM AUTHOR]

Highlights: [•] Phosphine and arsine complexes of main group elements reviewed. [•] Structural data on main group phosphine and arsine complexes collated and compared. [•] Structural and spectroscopic data interpreted in terms of Lewis acidity of acceptor elements. [•] Bonding models compared with those used for transition element complexes. [ABSTRACT FROM AUTHOR]

Abstract: New 1,1′-disubstituted ferrocenyl stibines and bismuthine containing formyl group have been synthesized. All the compounds were characterized by IR, mass, 1H, 13C, COSY and HETCOR NMR spectroscopy. Crystal structures of stibine (1) and bismuthine (3) have been determined. C3-symmetric tris 1,1′-asymmetrically ferrocenyl substituted group V compounds are first of their kind, as not many examples are known even with other p-block metal/metalloids. [Copyright &y& Elsevier]

The tetradentate stibine and bismuthine ligands (o-([sup i]Pr[sub 2]P)C[sub 6]H[sub 4])[sub 3]Sb (L[sup P3][sub Sb]) and (o-([sup i]Pr[sub 2]P)C[sub 6]H[sub 4])[sub 3]Bi (L[sup P3][sub Bi]) react with CuCl and AgCl in THF at room temperature to afford (o-([sup i]Pr[sub 2]P)C[sub 6]H[sub 4])[sub 3]SbCu[sub 3](μ[sub 2]-Cl)[sub 3] (1), (o-([sup i]Pr[sub 2]P)C[sub 6]H[sub 4])[sub 3]SbAg[sub 3](μ[sub 2]-Cl)[sub 3] (2), (o-([sup i]Pr[sub 2]P)C[sub 6]H[sub 4])[sub 3]BiCu[sub 3](μ[sub 2]-Cl)3 (3), and (o-([sup i]Pr[sub 2]P)C[sub 6]H[sub 4])[sub 3]BiAg[sub 3](μ[sub 2]-Cl)[sub 3] (4), respectively. These complexes, which have been fully characterised, feature a central M[sub 3](μ[sub 2]-Cl)[sub 3] cluster (M = Cu or Ag) supported by coordination of a L[sup P3][sub Sb]- or LL[sup P3][sub Bi]-phosphino group to each group 11 metal ion. The heavy pnictogen atom (Pn) interacts simultaneously with the three group 11 metal ions of the M[sub 3](μ[sub 2]-Cl)3 cluster leading to formation of a tetrahedral PnM[sub 3] core. Bonding analysis using the Natural Bond Orbital method indicates the presence of a four-centre two-electron Pn → M[sub 3] interaction whose strength is the highest in 1 and the lowest in 4. The triply bridging bonding mode of the stibine and bismuthine ligands observed in these complexes is, to our knowledge, unprecedented. We also note that the central M[sub 3](μ[sub 2]-Cl)[sub 3] clusters found in these complexes are related to the cyclo-trimers observed in vapours of CuCl and AgCl. [ABSTRACT FROM AUTHOR]

A new approach for the chemical synthesis of colloidal indium antimonide (InSb) nanocrystals is reported. It relies on the in situ generation of stibine gas (SbH3) as the antimony precursor and yields highly crystalline particles with a mean diameter of 8.8 nm and low size dispersion (13%). A synthetic pathway for the preparation of larger particles (≈100 nm) is also presented. [ABSTRACT FROM AUTHOR]

A new tetranuclear magnesium hydride cluster, [{ NN-(MgH)2}2], which was based on a NN-coupled bis-β-diketiminate ligand ( NN2−), was obtained from the reaction of [{ NN-(Mg nBu)2}2] with PhSiH3. Its crystal structure reveals an almost-tetrahedral arrangement of Mg atoms and two different sets of hydride ions, which give rise to a coupling in the NMR spectrum ( J=8.5 Hz). To shed light on the relationship between the cluster size and H2 release, the thermal decomposition of [{ NN-(MgH)2}2] and two closely related systems that were based on similar ligands, that is, an octanuclear magnesium hydride cluster and a dimeric magnesium hydride species, have been investigated in detail. A lowering of the H2-desorption temperature with decreasing cluster size is observed, in line with previously reported theoretical predictions on (MgH2) n model systems. Deuterium-labeling studies further demonstrate that the released H2 solely originates from the oxidative coupling of two hydride ligands and not from other hydrogen sources, such as the β-diketiminate ligands. Analysis of the DFT-computed electron density in [{ NN-(MgH)2}2] reveals a counterintuitive interaction between two formally closed-shell H− ligands that are separated by 3.106 Å. This weak interaction could play an important role in H2 desorption. Although the molecular product after H2 release could not be characterized experimentally, DFT calculations on the proposed decomposition product, that is, the low-valence tetranuclear Mg(I) cluster [( NN-Mg2)2], predict a structure with two almost-parallel, localized MgMg bonds. As in a previously reported β-diketiminate MgI dimer, the MgMg bond is not characterized by a bond critical point, but instead displays a local maximum of electron density midway between the atoms, that is, a non-nuclear attractor (NNA). Interestingly, both of the NNAs in [( NN-Mg2)2] are connected through a bond path that suggests that there is bonding between all four MgI atoms. [ABSTRACT FROM AUTHOR]

The tripodal tristibine N(CH2-2-C6H4SbMe2)3(L) has been prepared in high yieldand characterized by 1H and 13C{1H} NMR spectroscopy and elemental analysis. A range of reactionswith transition-metal acceptors were carried out to probe the coordinativeproperties of L. The 3/1 M/L complex [{FeCp(CO)2}3(L)-κSb:κSb′:κSb″][BF4]3involves tridentatebridging coordination of L to three CpFe(CO)2fragments.In [Mn(CO)3(L)][CF3SO3] the ligandadopts a tridentate chelating mode via a Sb3donor set;treatment of this complex with Me3NO in MeCN solution gavecrystals of [Mn(CO)2(L)(MeCN)][CF3SO3], which lost MeCN in vacuo, probably resulting in coordination ofCF3SO3–coordination of the[CF3SO3]−anion. [M(L)][BF4] (M = Ag, Cu) were also prepared. The reaction of L withCuBr leads to isolation of [Cu4Br4(L)2] in the solid state, which contains a Cu2Br4core with a short central Cu···Cu distance, cappedwith Cu(L) units at each end. The transition-metal complexes of Lwere characterized by elemental analysis, ESI+mass spectrometry,IR spectroscopy, and 1H, 13C{1H},and (where appropriate) 55Mn or 63Cu NMR spectroscopy.Solid-state X-ray structures were determined for [Mn(CO)3(L)][CF3SO3], [Mn(CO)2(L)(MeCN)][CF3SO3], [Cu4Br4(L)2], and [Cu3Br2(L)2][BF4]. In each of these structures the chelating ligand adopts a twisted,propeller-like conformation. NMR spectroscopic analysis suggests thatthe ligand also adopts this rigid conformation in solution. [ABSTRACT FROM AUTHOR]

The synthesis of a stable hydride triphenylstibine derivative,Nb(η5-C5H4SiMe3)2(H)(SbPh3) (1), has been achievedthrough the formation of the transient coordinatively unsaturated16-electron species [Nb(η5-C5H4SiMe3)2(H)] by thermolytic loss of H2from Nb(η5-C5H4SiMe3)2(H)3(2) followed by the coordinationof a triphenylstibine ligand. Low-temperature protonation of 1with a slight excess of CF3COOD led to the η2-dihydrogen complex 3as the monodeuterated H–Disotopomers of [Nb(η5-C5H4SiMe3)2(η2-HD)(SbPh3)]+CF3CO2–(3-d1). When thetemperature was increased to room temperature, complex 3was converted into the transoiddihydride [Nb(η5-C5H4SiMe3)2(H)2(SbPh3)]CF3CO2(4). Surprisingly, when CF3COOH in deuterated solvents wasused in the protonation process, the final η2-dihydrogenproduct always contained a substantial amount of deuterated isotopomers.Furthermore, a new hydrido olefin niobocene complex, [Nb(η5-(C5H4SiMe3)2(H)(trans-η2-C,C-PhCHCHPh)] (5), can be synthesized by elimination of the stibine ligandfrom 1followed by the addition of cisor transstilbene. Complex 5can alsobe obtained by reaction of 2in the presence of cisor transstilbene by the thermolyticloss of H2. All of these compounds were characterized byIR and multinuclear NMR spectroscopy, and the molecular structureof 5was determined by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Abstract: A one-pot stibine modified Co2(CO)8 homogeneous catalytic reductive N-alkylation of primary amides using aldehydes/ketones as alkylating agents, is reported. Good to excellent yields of a wide range of secondary amides are obtained (up to 97%) under relative mild conditions. [Copyright &y& Elsevier]