The room-temperature reaction of [Cp*TaCl4] with LiBH4⋅THF followed by addition of S2CPPh3 results in pentahydridodiborate species [(Cp*Ta)2(μ,η2:η2-B2H5)(μ-H)(κ2,μ-S2CH2)2] (1), a classical [B2H5]− ion stabilized by the binuclear tantalum template. Theoretical studies and bonding analysis established that the unusual stability of [B2H5]− in 1 is mainly due to the stabilization of sp2-B center by electron donation from tantalum. Reactions to replace the hydrogens attached to the diborane moiety in 1 with a 2 e {M(CO)4} fragment (M=Mo or W) resulted in simple adducts, [{(Cp*Ta)(CH2S2)}2(B2H5)(H){M(CO)3}] (6: M=Mo and 7: M=W), that retained the diborane(5) unit. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Sundargopal Ghosh

Department Of Chemistry

Koushik Saha

Sourav Kar

Suvam Saha

Rajarshi Halder

Beesam Raghavendra

Boron Compounds

Carbonylation

Lithium compounds

tantalum

Bonding analysis

DIBORANE

DITHIOLATES

ELECTRON DONATION

Metal carbonyl

theoretical study

Stabilization

Fulltext

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

Angewandte Chemie - International Edition

Stabilization of Classical [B2H5]−: Structure and Bonding of [(Cp*Ta)2(B2H5)(μ-H)L2] (Cp*=η5-C5Me5; L=SCH2S)

The field of diborinane is sparsely explored area, and not many compounds are structurally characterized. The room-temperature reaction of [{Cp∗RuCl(μ-Cl)} 2 ] (Cp∗ = η 5 -C 5 Me 5 ) with Na[BH 3 (SCHS)] yielded ruthenium dithioformato [{Cp∗Ru(μ,η 3 -SCHS)} 2 ], 1, and 1-thioformyl-2,6-tetrahydro-1,3,5-trithia-2,6-diborinane complex, [(Cp∗Ru){(η 2 -SCHS)CH 2 S 2 (BH 2 ) 2 }], 2. To investigate the reaction pathway for the formation of 2, we carried out the reaction of [(BH 2 ) 4 (CH 2 S 2 ) 2 ], 3, with 1 that yielded compound 2. To the best of our knowledge, it appears that compound 2 is the first example of a ruthenium diborinane complex where the central six-membered ring [CB 2 S 3 ] adopts the chair conformation. Furthermore, room temperature reaction of 1 with [BH 3 ·thf] resulted in the isolation of agostic-bis(σ-borate) complex, [Cp∗Ru(μ-H) 2 BH(S-CH=S)], 4. Thermolysis of 4 with trace amount of tellurium powder led to formation of bis(bridging-boryl) complex, [{Cp∗Ru(μ,η 2 -HBS 2 CH 2 )} 2 ], 5, via dimerization of 4 followed by dehydrogenation. Compound 5 can be considered as a bis(bridging-boryl) species, in which the boryl units are connected to two ruthenium atoms. Theoretical studies and chemical bonding analyses demonstrate the reason for exceptional reactivity and stability of these complexes. © 2019 American Chemical Society.

Inorganic Chemistry

Trithia-diborinane and Bis(bridging-boryl) Complexes of Ruthenium Derived from a [BH 3 (SCHS)] ? Ion

Aerobic oxidation of metallaborane compounds is an unexplored field apart from the few reports on accidental oxidation leading to oxametallaboranes. An effective method for the synthesis of group 5 oxametallaboranes has been developed by the oxidation of [(CpM) 2 (B 2 H 6 ) 2 ] (M = Ta/Nb) (Cp∗ = η 5 -C 5 Me 5 ). The reaction of [(CpM) 2 (B 2 H 6 ) 2 ] (M = Ta/Nb) with O 2 gas at room temperature yielded oxametallaboranes [(CpM) 2 (B 4 H 10 O)] (for 1, M = Nb; for 2, M = Ta). Density functional theory calculations signify an increase in the HOMO-LUMO energy gap for 1 and 2 as compared to that for the parent metallaboranes, [(CpM) 2 (B 2 H 6 ) 2 ] (M = Ta/Nb). Reaction of 1 and 2 with [Ru 3 (CO) 12 ] led to the isolation of fused metallaborane clusters [(CpNb) 2 (B 2 H 4 O){Ru(CO) 2 } 2 (B 2 H 4 ){Ru(CO) 3 } 2 {μ-H} 4 ] (3) and [(CpTa) 2 (B 3 H 4 O){Ru(CO) 2 } 3 {μ 7 -B}{μ-CO} 2 {μ-H} 4 ] (4). The structure of 3 may be considered as a fusion of five subunits [two tetrahedra (Td), two square pyramids (sqp), and one trigonal bipyramid (tbp)]. One of the key features of cluster 4 is the presence of a μ 7 -boride atom that shares three cluster units (one monocapped trigonal prism and two Td). All the compounds have been characterized by mass spectrometry, infrared spectroscopy, and 1 H, 13 C, and 11 B nuclear magnetic resonance spectroscopy, and the structural types were unequivocally established by crystallographic analysis of compounds 1, 3, and 4. © Copyright 2018 American Chemical Society.

Metal-Rich Oxametallaboranes of Group 5 Metals: Synthesis and Structure of a Face-Fused μ 7 -Boride Cluster

The reaction of [(Cp*Mo)2(μ-Cl)2B2H6] (1) with CO at room temperature led to the formation of the highly fluxional species [{Cp*Mo(CO)2}2{μ-η2:η2-B2H4}] (2). Compound 2, to the best of our knowledge, is the first example of a bimetallic diborane(4) conforming to a singly bridged Cs structure. Theoretical studies show that 2 mimics the Cotton dimolybdenum–alkyne complex [{CpMo(CO)2}2C2H2]. In an attempt to replace two hydrogen atoms of diborane(4) in 2 with a 2e [W(CO)4] fragment, [{Cp*Mo(CO)2}2 B2H2W(CO)4] (3) was isolated upon treatment with [W(CO)5⋅thf]. Compound 3 shows the intriguing presence of [B2H2] with a short B−B length of 1.624(4) Å. We isolated the tungsten analogues of 3, [{Cp*W(CO)2}2B2H2W(CO)4] (4) and [{Cp*W(CO)2}2B2H2Mo(CO)4] (5), which provided direct proof of the existence of the tungsten analogue of 2. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Synthesis, Structure, Bonding, and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)2}2{μ-η2:η2-B2H4}] and [{Cp*M(CO)2}2B2H2M(CO)4], M=Mo,W

A combined experimental and quantum chemical study of Group 7 borane, trimetallic triply bridged borylene and boride complexes has been undertaken. Treatment of [{Cp∗CoCl}2] (Cp∗=1,2,3,4,5-pentamethylcyclopentadienyl) with LiBH4·thf at -78°C, followed by room-temperature reaction with three equivalents of [Mn2(CO)10] yielded a manganese hexahydridodiborate compound [{(OC)4Mn}(η6-B2H6){Mn(CO)3}2(μ-H)] (1) and a triply bridged borylene complex [(μ3-BH)(Cp∗Co)2(μ-CO)(μ-H)2MnH(CO)3] (2). In a similar fashion, [Re2(CO)10] generated [(μ3-BH)(Cp∗Co)2(μ-CO)(μ-H)2ReH(CO)3] (3) and [(μ3-BH)(Cp∗Co)2(μ-CO)2(μ-H)Co(CO)3] (4) in modest yields. In contrast, [Ru3(CO)12] under similar reaction conditions yielded a heterometallic semi-interstitial boride cluster [(Cp∗Co)(μ-H)3Ru3(CO)9B] (5). The solid-state X-ray structure of compound 1 shows a significantly shorter boron-boron bond length. The detailed spectroscopic data of 1 and the unusual structural and bonding features have been described. All the complexes have been characterized by using 1H, 11B, 13C NMR spectroscopy, mass spectrometry, and X-ray diffraction analysis. The DFT computations were used to shed light on the bonding and electronic structures of these new compounds. The study reveals a dominant B-H-Mn, a weak B-B-Mn interaction, and an enhanced B-B bonding in 1. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Chemistry - A European Journal

First-Row Transition-Metal-Diborane and -Borylene Complexes

Journal	Data powered by TypesetAngewandte Chemie - International Edition
Publisher	Data powered by TypesetWiley-VCH Verlag
ISSN	14337851
Open Access	Yes