Chemistry and reactivity of dimolybdathiaborane, [(Cp*Mo) 2B2SH2], 1, obtained from the reaction of 2-mercaptobenzothiazole, [Cp*MoCl2] and [LiBH2.thf], has been explored with dinuclear metal carbonyl [Fe2(CO) 2]. As a result, reaction of 1 with [Fe2(CO)2] yielded heterometallathiaborane, [(Cp*Mo)2B2H 2SFe(CO)2], 2 in good yield. Both the new compounds have been characterized in solution by 1H, 11B and 13C NMR spectroscopy and the structural types were unequivocally established by X-ray crystallographic analysis of compound 2. Cluster 2 has a bicapped octahedral geometry with the {Fe(CO)3} fragment occupying one of the high-connectivity cluster vertexes rather than a capping position. Interestingly, cluster 1 undergoes geometric changes (bicapped trigonal bipyramid → bicapped octahedron) on the addition of two-electron {Fe(CO)3} fragment to 1. © Indian Academy of Sciences.

Sundargopal Ghosh

Department Of Chemistry

Carbonylation

Nuclear magnetic resonance spectroscopy

Organometallics

X ray crystallography

13C NMR SPECTROSCOPY

2-MERCAPTOBENZOTHIAZOLE

Boranes

cluster

HIGH CONNECTIVITY

Metallaborane

Octahedral geometry

X-ray crystallographic analysis

Iron compounds

Fulltext

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IIT Madras

Journal of Chemical Sciences

We report the synthesis, isolation and structural characterization of several crystalline, moderately air stable nido-metallaboranes which represent novel metal rich open cage systems.The reaction of [Cp*CoCl]2, (Cp* = ν5-C5Me5), with [LiBH 4·thf] in toluene at-78 °C, followed by thermolysis with [BH3·thf] in boiling toluene yielded clusters, [(Cp*Co)3B6H8O] (1) and [(Cp*Co)2B8H11Me] (2). Under the similar reaction condition, [Cp*RhCl2]2 yielded [(Cp*Rh)3B7H11] (3) and [(Cp*Rh)2B8H12] (4). All the new compounds, 1-4 have been characterized by elemental analysis, IR, 1H, 11B, 13C NMR spectroscopy, and the geometric structures were unequivocally established byX-ray diffraction analysis of compound 1-4. Quantum chemical calculation by using density functional theory method is implemented on model compounds 10-40 (10-40 are the Cp analogs of 1-4 respectively, Cp = C5H5) and yields geometries in agreement with the X-ray detaermined geometries. Large HOMO-LUMO gaps are in tally with the higher stabilities of 10 and 30. © The National Academy of Sciences, India 2014.

Proceedings of the National Academy of Sciences India Section A - Physical Sciences

Synthesis, characterization and electronic structures of Rh and co analogs of decaborane-14

Recently we described the synthesis and structural characterization of various dimetallaherteroborane clusters, namely nido-[(Cp∗Mo)2B4ECl x H6-x ], 1-3; (1: E = S, x = 0; 2: E = Se, x = 0; 3: E = Te, x = 1). A combined theoretical and experimental study was also performed, which demonstrated that the clusters 1-3 with their open face are excellent precursors for cluster growth reaction. In this investigation process on the reactivity of dimetallaheteroboranes with metal carbonyls, in addition to [(Cp∗Mo)2B4H6EFe(CO)3] (4: E = S, 6: E = Te) reported earlier, reaction of 2 with [ Fe2(CO)9] yielded mixed-metallaselenaborane [(Cp∗Mo)2B4H6SeFe(CO)3], 5 in good yield. The quantum chemical calculation using DFT method has been carried out to probe the bonding, NMR chemical shifts and electronic properties of dimolybdaheteroborane clusters 4-6. [Figure not available: see fulltext.] © 2014 Indian Academy of Sciences.

Dimetallaheteroborane clusters containing group 16 elements: A combined experimental and theoretical study

Reaction of [Cp*CoCl]2 (Cp* = η5-C5Me5) with [LiBH4· THF] in toluene at -70 C, followed by thermolysis with 2-mercaptobenzothiazole (C7H5NS2) in boiling toluene led to the isolation of a range of cobaltaborane clusters, [(Cp*Co) 2B7H6OMe], 1; [(Cp*Co) 3B8H7R], 2a, b (2a: R = H; 2b: R = Me); [(Cp*Co)3B8H8S], 3 and [(Cp*Co)2B4H4RR′], 4a-d (4a: R, R′ = H; 4b: R = Me, R′ = H; 4c: R = H, R′ = Me and 4d: R, R′ = Me). In parallel to the formation of compounds 1-4, the reaction also yielded known [(Cp*Co)3B4H 4] in good yield. Compound 1 may be considered as 9-vertex hypoelectronic cluster with C1 symmetry, where cobalt atoms occupy the degree 5 vertices. All the dicobaltaboranes 4a-d contains two μ3-H protons and found to be very reactive. As a result, one of them (4a) when reacted with Fe2(CO)9 and sulfur powder yielded, almost immediately, [(Cp*Co)2B 4H5SFe3(CO)9], 5 and [(Cp *Co)2B3H3(μ-CO)Fe(CO) 3], 6. All the new compounds have been characterized in solution by mass, 1H, 11B, 13C NMR spectroscopy and elemental analysis. The structural types were unequivocally established by X-ray crystallographic analysis of compounds 1-6. Density functional theory (DFT) calculations on the model compounds 1′ and 2′ (1′, and 2′ are the Cp analog of 1, and 2a respectively, Cp = C5H 5) yield geometries in agreement with the structure determinations. The existence of large HOMO-LUMO gap of these molecules rationalizes the isocloso description for 2a. Bonding patterns in the structure have been analyzed on the grounds of DFT calculations. © 2013 Elsevier B.V. All rights reserved.

Journal of Organometallic Chemistry

Hypoelectronic metallaboranes: Synthesis, structural characterization and electronic structures of metal-rich cobaltaboranes

The reaction of an intermediate, generated from [Cp#MoCl 4] [Cp# = Cp or Cp; Cp = (η5-C 5H5), Cp= (η5-C5Me5)] and LiBH4.thf, with different chalcogen ligands yielded trimolybdaborane clusters 1-3, [(Cp#Mo)3(μ-H)B 8H6X2], (1: Cp# = Cp, X = H; 2: Cp# = Cp, X = H; 3: Cp# = Cp, X = Cl). Compounds 1-3 constitute an example of an unsaturated (n-4) sep cluster having very close structural similarities. These clusters represent 11-vertex boron-rich metallaboranes containing 66 cluster valence electrons (cve). All the compounds were fully characterized by various spectroscopic techniques, elemental analysis and the solid state structures were unequivocally established by X-ray diffraction analysis of 1-3. © 2012 Elsevier B.V. All rights reserved.

A close-packed boron-rich 11-vertex molybdaborane with novel geometry

The reaction of [(Cp*Ta)2B4H 9(μ-BH4)] (1; Cp* = η5-C5Me5) with [Fe2(CO) 9] in hexane yielded [(Cp*Ta)2B 5H7{Fe(CO)3}2] (2) and [(Cp *Ta)2B5H9{Fe(CO) 3}4](3) in moderate yield. Cluster 2 represents the first example of a bicapped pentagonalbipyramidal metallaborane with a deformed equatorial plane, and 3 can be described as a fused cluster in which two pentagonalbipyramidal units are fused through a common 3-vertex triangular face. Compounds 2 and 3 have been characterized by mass spectrometry and IR, 1H, 11B, and 13C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis. © 2011 American Chemical Society.

Inorganic Chemistry

Condensed tantalaborane clusters: Synthesis and structures of [(Cp *Ta)2B5H7{Fe(CO) 3}2] and [(Cp*Ta)2B 5H9{Fe(CO)3}4]

Chalcogen-stabilized dimolybdaboranes 3-5 (3: [(Cp*MO) 2B4H5Se(Ph)], 4: [(Cp*MO) 2B4H3Se2(SeCH2Ph)] and 5: [(Cp*MO)2B3H6(BSR)(μ- η1-SR)] (R = 2,6-(tBu)2-C6H 2OH)) have been isolated from the mild pyrolysis of dichalcogenide ligands, RE-E'R (R = Ph: E = S, E' = Se; R = CH2Ph, [2,6-(tBu) 2-C6H2OH]: E = E' = Se, S) and [(Cp*MO)2B4H8], 2, an intermediate generated from the reaction of [Cp/MoCl4] (1) (Cp* = η5-C5Me5), with [LiBH4.thf]. The geometry of [(Cp*MO)2B4H5Se(Ph)] is similar to that of [(Cp*MO)2B5H9], in which one BH3 unit on the open face is replaced by a triple bridged selenium atom. All the compounds have been characterized in solution by 1H, 11B, 13C NMR and IR spectroscopy and elemental analysis. The structural types were unequivocally established by X-ray crystallographic analysis of compounds 3-5. © 2011 Elsevier Ltd.

Polyhedron

Synthesis, structure and characterization of dimolybdaheteroboranes

Metal-rich metallaboranes: An exo-Fe(CO)3 moiety linked to a cubane core is the most prominent feature of complexes [(Cp*M) 2(μ3-E)2B2H(μ-H){Fe(CO) 2}2Fe(CO)3] (M=Mo, E=S, Se; M=Ru, E=CO; Cp*=n5-C5Me5), which are the first heterobimetallic cubane-type clusters with a boride unit (see structure). © 2011 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Angewandte Chemie - International Edition

A family of heterometallic cubane-type clusters with an exo-Fe(CO) 3 fragment anchored to the cubane

Pyrolysis of an in-situ generated intermediate, produced in the reaction of [CpMoCl4], 1, (Cp= η5-C5Me5) with [LiBH4·THF], with an excess of difuryl ditelluride in toluene at 90 °C yielded syn and anti isomers of [CpMo(O)(μ-Te)] 2 (2, 3) and [Cp2Mo2O2(μ-O)(μ- Te)] (4, 5). In a similar fashion, dibenzyl diselenide yielded syn and anti isomers of [CpMo(O)(μ-Se)]2 (6, 7), along with the known nido-[(CpMo)2B4H8Se2]. Note that in parallel with 2-7, [(CpMo)2B5H9] was isolated as the major product in both cases. Compounds 2-7 have been isolated in modest yield as orange to brown crystalline solids. All the new compounds have been characterized in solution by mass, IR, 1H, 13C, 77Se and 125Te NMR spectroscopy, and the structural types were unequivocally established by crystallographic analysis of 2-4 and 7. © 2011 Elsevier Ltd. All rights reserved.

Synthesis and characterization of binuclear μ-oxo and μ-telluro molybdenum(V) complexes, [Cp*Mo(O)(μ-Te)]2

Vanadaborane, [(CpV)2(B2H6)2] (Cp = η5-C5H5), 1 reacts with elemental sulfur to afford the hexasulflde cluster [(CpV)2S4(μ- η1-S2)], 2 In high yield. Compound 2 is a notable example of an organovanadium sulfide cluster In which the [V2S 4] atoms define a bicapped tetrahedron framework, with μ-η1-S2 ligand bridged the two (CpV) moieties. The sulfur atom In [V2S4] core in 2 Is a four-skeletal- electron donor isoelectronlc with the BH3 unit; therefore, the replacement of boron hydride in 1 by four sulfur atoms necessitates the formation of a bicapped tetrahedron [V2S4] framework. Furthermore, this Is the only reported example of a bimetallic hexasulflde cluster containing vanadium. Pyrolysls of 1 with bis-chalcogenide ligands such as Ph2S2 and Bz2Se2 (Bz = PhCH 2), results In the formation of substituted vanadahexaboranes [(CpV)2B4H12-xLx], 3-5 (3: L = SPh: x= 3; 4: L = SPh, x= 2; 5: L = SeBz: x= 1) in modest yield. All these new compounds have been characterized by mass, 1H, 11B, 13C NMR spectroscopy, and elemental analysis, and the structural types were unequivocally established by crystallographic analysis of compounds 2-5. © 2010 American Chemical Society.

Journal	Data powered by TypesetJournal of Chemical Sciences
Publisher	Data powered by TypesetSpringer India
ISSN	09743626
Open Access	Yes