This work reports the synthesis and structural characterization of a hydrogen-rich tantalaborane cluster, [(Cp*Ta)(Cp*TaCl)B 9H16] (2, Cp* = η5-C 5Me5), obtained from the thermolysis of [BH 3•thf] and an in situ generated intermediate, produced from the reaction of [Cp*TaCl4], 1, and [LiBH4•thf]. Cluster 2 has an 11-vertex nido-cage geometry. The core geometry of 2 can be derived from an icosahedron by removing the apical five-coordinate vertex. The title cluster is a rare example of an electronically unsaturated metallaborane containing four TaHB and three BHB bonds. © 2011 American Chemical Society.

Sundargopal Ghosh

Department Of Chemistry

ELECTRON PAIR

ELECTRONICALLY UNSATURATED

In-situ

Structural characterization

Synthesis (chemical)

Reaction intermediates

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Organometallics

We report the synthesis and structural characterization of moderately air stable metal rich metallaboranes of iridium. Treatment of [Cp*IrCl2]2with BH3·thf at high temperature led to the isolation of a trimetallic [nido-5-(Cp*Ir)3B7H11], 1. Compound 1 is isoelectronic and isostructural with decaborane-14 where three BH units in [B10H14] have been replaced by Cp*Ir fragments. As far as we are aware, 1 is the first example of a iridadecaborane having three metals. In addition to the formation of 1, a change in the reaction conditions enabled us to isolate a 7 sep [(Cp*Ir)3B4H4], 2. The geometry of 2 can be viewed as a condensed polyhedron composed of Ir3B3octahedron capped by a BH unit. All the compounds have been characterized by IR and1H,11B, and13C NMR spectroscopy in solution, and the solid-state structures were established by X-ray crystallographic analysis. Quantum-chemical calculations by DFT methods for compounds 1 and 2 showed reasonable agreement with the experimentally observed structural parameters. The large HOMO–LUMO gaps are consistent with the high stabilities of the iridium clusters compared to their known Rh and Co analogues. © 2016 Elsevier B.V.

Journal of Organometallic Chemistry

Metal rich metallaboranes of group 9 transition metals

Thermolysis of an in situ generated intermediate [(Cp∗Ta)2(BH3)2Cl2], 1 generated from the reaction of [Cp∗TaCl4], (Cp∗ = η5-C5Me5) and [LiBH4•thf], in presence of [Ru3(CO)12] yielded pileo-[Cp∗TaCl(μ-Cl)-B2H4Ru3(CO)8], 2 having two electrons fewer than seven pairs required for the observed square pyramidal geometry. Cluster 2 is the first example of an unsaturated cluster comprising early and late transition metals in a square pyramid core. This reaction also yielded [(Cp∗Ta)2(B2H6)(B2H4Cl2)], 3 as a by-product. In addition, the reaction of [Cp∗MoCl4] (Cp∗ = η5-C5Me5) with [LiBH4·thf] in presence of excess [MeI] at mild condition led to the isolation of periodinated dimolybdatetraborane [(Cp∗Mo)2B4H3I5], 4 that hints a possible existence of [(Cp∗Mo)2B4H8]. After the isolation of periodinated 4, we extended this chemistry towards the late transition metallaborane [(Cp∗Rh)3B4H4], 5 using [PtBr2] as brominating source. Although all the attempts to isolate perbrominated rhodaborane failed, we have isolated partially brominated rhodaborane clusters [(Cp∗Rh)3(BH)-(BBr)3], 6 and [(Cp∗Rh)3(BH)3(BBr)], 7. All the compounds were characterized by IR and 1H, 11B and 13C NMR spectroscopy in solution, and the solidstate structures of 2, 4 and 6 were established by crystallographic analysis. © 2014 IUPAC & De Gruyter.

Fulltext

Pure and Applied Chemistry

Chemistry of early and late transition metallaboranes: Synthesis and structural characterization of periodinated dimolybdaborane [(Cp∗Mo)2B4H3I5]

Journal of the American Chemical Society

Synthesis and Characterization of Hypoelectronic Rhenaboranes. Analysis of the Geometric and Electronic Structures of Species Following Neither Borane nor Metal Cluster Electron-Counting Paradigms

Angewandte Chemie International Edition

Synthesis of [(Cp*Re)2BnHn]n=8-10: Metal Boride Particles That Stretch the Cluster Structure Paradigms

Journal	Organometallics
ISSN	02767333
Open Access	No