In an effort to synthesize supraicosahedral iridaboranes, pyrolysis of [Cp∗IrCl2]2 with excess [BH3·THF] was carried out, and this synthesis afforded the isomeric iridaborane [(Cp∗Ir)2B6H6] clusters 1 and 2. The geometry of 1 was determined to be dodecahedral, i.e., similar to that of [B8H8]2-, whereas 2 was found to exhibit a cluster shape that can be derived from a nine-vertex tricapped trigonal prism by removing one of the capped vertices. The calculation of a large HOMO-LUMO gap further rationalized the isocloso structures for these isomers. © The Royal Society of Chemistry 2016.

Sundargopal Ghosh

Department Of Chemistry

Rosmita Borthakur

Bijan Mondal

Purbasha Nandi

borane derivative

DIIRIDABORANE DERIVATIVE

unclassified drug

article

chemical structure

geometry

infrared spectroscopy

isomer

Mass spectrometry

proton nuclear magnetic resonance

Pyrolysis

synthesis

X ray diffraction

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IIT Madras

Chemical Communications

Room-temperature reactions between [Cp*CoCl]2 (Cp∗ = ν5-C5Me5) and large excess of [BH2E3]Li (E = S or Se) led to the formation of homocubane derivatives, 1-7. These species are bimetallic tetrahomocubane, [(Cp*Co)2(μ-S)4(μ3-S)4B2H2], 1; bimetallic trishomocubane isomers, [(Cp*Co)2(μ-S)3(μ3-S)4B2H2], 2 and 3; monometallic trishomocubanes, [M(μ-E)3(μ3-E)4B3H3] [4: M = Cp*Co, E = S; 5: M = Cp*Co, E = Se and 6: M = {(Cp*Co)2(μ-H)(μ3-Se)2}Co, E = Se], and bimetallic homocubane, [(Cp*Co)2(μ-Se)(μ3-Se)4B2H2], 7. As per our knowledge, 1 is the first isolated and structurally characterized parent prototype of the 1,2,2′,4 isomer of tetrahomocubane, while 3, 4, and 5 are the analogues of parent D3-trishomocubane. Compounds 2 and 3 are the structural isomers in which the positions of the μ-S ligands in the trishomocubane framework are altered. Compound 6 is an example of a unique vertex-fused trishomocubane derivative, in which the D3-trishomocubane [Co(μ-Se)3(μ3-Se)4B3H3] moiety is fused with an exopolyhedral trigonal bipyramid (tbp) moiety [(Cp*Co)2(μ-H)(μ3-Se)2}Co]. Multinuclear NMR and infrared spectroscopy, mass spectrometry, and single crystal X-ray diffraction analyses were employed to characterize all the compounds in solution. Bonding in these homocubane analogues has been elucidated computationally by density functional theory methods. © 2019 American Chemical Society.

Fulltext

ACS Omega

Homocubane Chemistry: Synthesis and Structures of Mono- And Dicobaltaheteroborane Analogues of Tris- And Tetrahomocubanes

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

A series of novel isocloso-diiridaboranes [(Cp∗Ir)2B6H6], 1, 2; [1,7-(Cp∗Ir)2B8H8], 4; [1,4-(Cp∗Ir)2B8H8], 5; [(Cp∗Ir)2B9H9], 8; isonido-[(Cp∗Ir)2B7H7], 3; and 10-vertex cluster [5,7-(Cp∗Ir)2B8H12], 6 (Cp∗ = η5-C5Me5) have been isolated and structurally characterized from the pyrolysis of [Cp∗IrCl2]2 and BH3·thf. On the other hand, the corresponding rhodium system afforded 10- and 11-vertices clusters [5-(Cp∗Rh)B9H13)], 7, and [(Cp∗Rh)2B9H9], 9, respectively. Clusters 1 and 2 are topological isomers. The geometry of 1 is dodecahedral, similar to that of its parent borane [B8H8]2-, in which two of the [BH] vertices are replaced by two [Cp∗Ir] fragments. The geometry of 2 can be derived from a nine-vertex tricapped trigonal prism by removing one of the capped vertices. Compounds 4 and 5 are 10-vertex isocloso clusters based on a 10-vertex bicapped square antiprism structure. The only difference between them is the presence of a metal-metal bond in 5. The solid-state structures of 8 and 9 attain an 11-vertex geometry in which a unique six-membered B6H6 moiety is bonded to the metal center. In addition, quantum-chemical calculations have been used to provide further insight into the electronic structure and stability of the clusters. All the compounds have been characterized by IR and 1H, 11B, and 13C NMR spectroscopy in solution, and the solid-state structures were established by X-ray crystallographic analysis. © 2016 American Chemical Society.

Inorganic Chemistry

Hypoelectronic 8-11-Vertex Irida- and Rhodaboranes

The recent achievements and progress in the field of high-nuclearity supraicosahedral metallaborane chemistry are reviewed and compared to those made in borane, carborane and metallacarborane chemistry. In contrast to metallacarboranes, characterized large supraicosahedral metallaboranes only adopt isocloso deltahedral structural arrangements with n vertices and a non-Wadean n skeletal-electron-pair count. This anomaly can be rationalized by the preference of metal atoms for 6-connect vertices present in the cluster cages. © 2013 Springer Science+Business Media New York.

Journal of Cluster Science

Beyond the Icosahedron: The Quest for High-Nuclearity Supraicosahedral Metallaboranes

A series of novel Cp*-based (Cp*=η5-C 5Me5) agostic, bis(σ-borate), and boratrane complexes have been synthesized from diruthenium and dirhodium analogues of pentaborane(9). The synthesis and structural characterization of the first neutral ruthenadiborane(6) analogue are also reported. This new route offers a very efficient method for the isolation of bis(σ-borate) and agostic complexes from diruthenapentaborane(9). © 2014 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Angewandte Chemie - International Edition

Reactivity of diruthenium and dirhodium analogues of pentaborane(9): Agostic versus boratrane complexes

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.

Boron beyond the icosahedral barrier: A 16-vertex metallaborane

This work reports the results of a thermally driven cluster expansion of arachno-1-{η5-C<inf>5</inf>Me<inf>5</inf>IrH<inf>2</inf>}B <inf>3</inf>H<inf>7</inf>, 1, with BH<inf>3</inf>•THF. In addition to the previously reported product, arachno-1-{η5-C<inf>5</inf>Me <inf>5</inf>IrH}B<inf>4</inf>H<inf>9</inf>, 2, formed at lower temperatures, reaction at 100 °C permits the isolation of four new iridaboranes. Two products, nido-1-(η5-C<inf>5</inf>Me<inf>5</inf>Ir)B <inf>5</inf>H<inf>9</inf>, 3, and nido-3-(η5-C<inf>5</inf>Me <inf>5</inf>Ir)B<inf>9</inf>H<inf>13</inf>, 4, contain a single Ir atom and five and nine framework boron atoms, respectively. One, nido-3,4-(η5- C<inf>5</inf>Me<inf>5</inf>Ir)<inf>2</inf>B<inf>8</inf>H<inf>12</inf>, 5, contains two Ir atoms and eight framework boron atoms. Their structures are predicted by the electron counting rules to be a nido-iridahexaborane, 3, nido-iridadecaborane, 4, and nido-diiridadecaborane, 5. The accuracy of these predictions in each case is established experimentally by spectroscopic characterization in solution and structure determinations in the solid state. A less stable metallaborane has been identified and the available spectroscopic and crystallographic information are consistent with the formulation nido-3,4-(η5-C<inf>5</inf>Me<inf>5</inf>Ir)<inf>2</inf>B <inf>8</inf>H<inf>13</inf>(μ-BH<inf>2</inf>), 6, i.e., a species containing an exopolyhedral bridging BH group. These new observations, along with earlier ones on ruthenaborane cluster systems, are used to fully define a general mechanism for a cluster expansion reaction, i.e., addition of borane to form an exopolyhedral adduct followed by cage insertion. © The Royal Society of Chemistry.

Dalton Transactions

Expansion of iridaborane clusters by addition of monoborane. Novel metallaboranes and mechanistic detail

Chemistry - An Asian Journal

Recent Progress in the Chemistry of Supercarboranes

Hypoelectronic isomeric diiridaboranes [(Cp∗Ir)2B6H6]: The "rule-Breakers"(Cp∗ = η5-C5Me5)

Journal	Data powered by TypesetChemical Communications
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	13597345
Open Access	No