The first example of a homometallic neutral zirconaborane, [(Cp2Zr)2B5H11], 1, has been prepared through the thermolysis of [Cp2Zr(BH4)2], generated from the fast metathesis reaction of [Cp2ZrCl2] and LiBH4·thf with BH3·thf. The solid-state structure of 1 shows an open geometry with a planar B3 ring. The bonding between the Zr center and the central B3 ring was studied computationally by DFT methods, and based on the combined experimental and computational results compound 1 can be defined as a metal-stabilized arachno-B3H9. Further, in an attempt to synthesize a hybrid analogue of 1 by introducing two electron fragments into arachno-[(Cp2Zr)(Cp∗Ir)B4H10], 2, we have performed the reaction of 2 with [Ru3(CO)12]. However, the reaction led to the formation of a hybrid metallaborane, [(Cp∗Ir){Ru3(CO)8}B4H10], 3. © 2015 American Chemical Society.

Sundargopal Ghosh

Department Of Chemistry

Bijan Mondal

Anangsha De

Iridium

ruthenium

Computational results

DFT method

Metathesis reactions

Open geometry

Solid-state structures

Zirconium

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IIT Madras

Organometallics

In an attempt to expand the library of M 2 B 5 bicapped trigonal-bipyramidal clusters with different transition metals, we explored the chemistry of [Cp*WCl4] with metal carbonyls that enabled us to isolate a series of mixed-metal tungstaboranes with an M 2 [B 4 M'] [M =W; M' = Cr(CO) 4 , Mo(CO) 4 , W(CO) 4 ] core. The reaction of in situ generated intermediate, obtained from the low temperature reaction of [Cp*WCl 4 ] with an excess of [LiBH 4 ·thf], followed by thermolysis with [M(CO) 5 ·thf] (M = Cr, Mo and W) led to the isolation of the tungstaboranes [(Cp*W) 2 B 4 H 8 M(CO) 4 ], 1-3 (1: M = Cr; 2: M = Mo; 3: M = W). In an attempt to replace one of the BH-vertices in M 2 B 5 with other group metal carbonyls, we performed the reaction with [Fe 2 (CO) 9 ] that led to the isolation of [(Cp*W) 2 B 4 H 8 Fe(CO) 3 ], 4, where Fe(CO) 3 replaces a [BH] core unit instead of the [BH] capped vertex. Further, the reaction of [Cp*MoCl 4 ] and [Cr(CO) 5 ·thf] yielded the mixed-metal molybdaborane cluster [(Cp*Mo) 2 B 4 H 8 Cr(CO) 4 ], 5, thereby completing the series with the missing chromium analogue. With 56 cluster valence electrons (cve), all the compounds obey the cluster electron counting rules. Compounds 1-5 are analogues to the parent [(Cp*M) 2 B 5 H 9 ] (M= Mo and W) that seem to have generated by the replacement of one [BH] vertex from [(Cp*W) 2 B 5 H 9 ] or [(Cp*Mo) 2 B 5 H 9 ] (in case of 5). All of the compounds have been characterized by various spectroscopic analyses and single crystal X-ray diffraction studies. © 2019 by the authors.

Fulltext

Inorganics

Synthesis, structures and chemistry of the metallaboranes of group 4-9 with M 2 B 5 core having a cross cluster M-M bond

A neutral metallaborane comprising a Rh4B12 polyhedron with icosioctahedron geometry with 16 vertices and 28 triangular faces was prepared (see structure; Rh: red, B: green). The cage has the shape of a 12-membered truncated tetrahedron with four capped hexagonal faces. © 2013 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Angewandte Chemie - International Edition

Boron beyond the icosahedral barrier: A 16-vertex metallaborane

Metal assisted borane condensation method has been employed for the preparation of novel metallaborane cluster containing group 4 metal. Pyrolysis of [Cp*IrB3H9], 1, with in situ generated zirconium bisborohydrate [Cp2Zr(BH4)2], produced from the fast metathesis reaction of [Cp2ZrCl2] and LiBH 4, and excess of BH3·THF yielded arachno-[(Cp 2Zr)(Cp*Ir)B4H10], 2, in 56% yield. Compound 2 constitutes the first crystallographic structure determination of hexaborane(12) metal analogue containing zirconium. The observed geometry of 2 can be generated from a dodecahedron by removing two vertices and an edge. Anticipating a straight metal fragment substitution/addition reaction, mild thermolysis of 2 with [Fe2(CO)9] was carried out. However, the reaction led to the formation of known trimetallic [Cp*IrFe 2(CO)9] cluster via cluster degradation. In addition, density functional theory (DFT) calculations have been carried out for 2 and other hypothetical early-late combinations of hexaborane(12) metal analogues to reveal the electronic structures. © 2013 American Chemical Society.

An early-late transition metal hybrid analogue of hexaborane(12)

Chemical Communications

Unexpected cluster formation upon hydroboration of a neutral diborene with 9-BBN

Chemical Reviews

Nucleus-Independent Chemical Shifts (NICS) as an Aromaticity Criterion

Valency and Bonding

Novel neutral zirconaborane [(Cp2Zr)2B5H11]: An arachno -B3H9 analogue (Cp = η5-C5H5)

Journal	Data powered by TypesetOrganometallics
Publisher	Data powered by TypesetAmerican Chemical Society
ISSN	02767333
Open Access	No