Mild thermolysis of arachno-[(Cp*RuCO)2B2H 6], 1 in presence of GeCl2·dioxane yielded di-μ-germylene complex [(Cp*Ru)2(μ-GeCl2) 2(CO)2], 2 (Cp* = η5-C 5Me5). The molecular structure of 2 exhibits a diruthenium unit bridged by a pair of μ-GeCl2 moieties. The Cp* and the terminal CO ligands are oriented in anti fashion with respect to Ru-Ru bond. In addition, the reaction of 2 with arachno-[CpFe(CO)B3H8] (Cp = η5-C5H5) transformed to germenocene, [Cp2Ge:], 3 via an unstable intermediate [CpFe(CO)B2H 5GeCl2], I. The 11B NMR spectroscopy was used as a tool to establish a probable reaction pathway for the formation of germenocene 3. Cluster 2 has been characterized by IR and NMR spectroscopy, and the geometric structure was unequivocally established by crystallographic analysis. © 2013 Elsevier B.V. All rights reserved.

Sundargopal Ghosh

Department Of Chemistry

Binary alloys

chelation

Chlorine compounds

Germanium

Ligands

Nuclear magnetic resonance spectroscopy

Reaction intermediates

ruthenium

Ruthenium alloys

Ruthenium compounds

CRYSTALLOGRAPHIC ANALYSIS

GEOMETRIC STRUCTURE

GERMENOCENE

GERMYLENE COMPLEXES

Germylenes

IR AND NMR SPECTROSCOPY

Metallaborane

Structural characterization

Germanium compounds

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

Journal of Organometallic Chemistry

In an attempt to synthesize a zero valent germanium compound, we have carried out the reaction of [(Cp∗RuCO)(GeCl2)]2, 1 with potassium metal that led to the formation of a metallagermoxane [(Cp∗Ru(CO)2Ge)4(μ-O)6], 2. Compound 2 is the first example of a tetrametallagermoxane with an exo-{Cp∗Ru(CO)2} fragment. DFT calculations were used to examine the key intermediates associated with the formation of 2. © 2015 The Royal Society of Chemistry.

Dalton Transactions

All-metallagermoxane with an adamantanoid cage structure: [(Cp∗Ru(CO)2Ge)4(μ-O)6] (Cp∗ = η5-C5Me5)

Room temperature photolysis of a triply-bridged borylene complex, [(μ3-BH)(Cp*RuCO)2(μ-CO)Fe(CO)3] (1 a; Cp*=C5Me5), in the presence of a series of alkynes, 1,2-diphenylethyne, 1-phenyl-1-propyne, and 2-butyne led to the isolation of unprecedented vinyl-borylene complexes (Z)-[(Cp*RuCO) 2(μ-CO)B(CR)(CHR′)] (2: R, R′=Ph; 3: R=Me, R′=Ph; 4: R, R′=Me). This reaction permits a hydroboration of alkyne through an anti-Markovnikov addition. In stark contrast, in the presence of phenylacetylene, a metallacarborane, closo-[1,2-(Cp*Ru) 2(μ-CO)2{Fe2(CO)5}-4-Ph-4,5- C2BH2] (5 a), is formed. A plausible mechanism has been proposed for the formation of vinyl-borylene complexes, which is supported by density functional theory (DFT) methods. Furthermore, the calculated 11B NMR chemical shifts accurately reflect the experimentally measured shifts. All the new compounds have been characterized in solution by mass spectrometry and IR, 1H, 11B, and 13C NMR spectroscopies and the structural types were unequivocally established by crystallographic analysis of 2, 5 a, and 5 b. Unique metal-borylene complexes: Photolysis of a triply bridged borylene complex [(μ3-BH) (Cp*RuCO)2(μ-CO)Fe(CO)3] (Cp*= η5-C5Me5) with various internal alkynes led to hydroboration yielding new vinyl-borylene complexes (see figure). A plausible mechanism has been proposed for the formation of vinyl-borylene complexes, which is supported by density functional theory (DFT) methods. Copyright © 2013 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Chemistry - A European Journal

Syntheses and characterization of new vinyl-borylene complexes by the hydroboration of alkynes with [(μ3-BH)(Cp*RuCO) 2(μ-CO)Fe(CO)3]

The reaction of nido-[1,2-(Cp*RuH)2B3H 7] (1 a, Cp*=Î·5-C5Me 5) with [Mo(CO)3(CH3CN)3] under mild conditions yields the new metallaborane arachno-[(Cp*RuCO) 2B2H6] (2). Compound 2 catalyzes the cyclotrimerization of a variety of internal- and terminal alkynes to yield mixtures of 1,3,5- and 1,2,4-substituted benzenes. The reactivities of nido-1 a and arachno-2 with alkynes demonstrates that a change in geometry from nido to arachno drives a change in the reaction from alkyne-insertion to catalytic cyclotrimerization, respectively. Density functional calculations have been used to evaluate the reaction pathways of the cyclotrimerization of alkynes catalyzed by compound 2. The reaction involves the formation of a ruthenacyclic intermediate and the subsequent alkyne-insertion step is initiated by a [2+2] cycloaddition between this intermediate and an alkyne. The experimental and quantum-chemical results also show that the stability of the metallacyclic intermediate is strongly dependent on the nature of the substituents that are present on the alkyne. Everything changes but Ru: The reactivities of nido-[1,2-(Cp*RuH)2B3H7] and arachno-[(Cp*RuCO)2B2H6] with alkynes show that a change in geometry (nido to arachno) drives a change from alkyne-insertion to catalytic cyclotrimerization, respectively. Copyright © 2012 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

A mechanistic study of the utilization of arachno-diruthenaborane [(Cp*RuCO)2B2H6] as an active alkyne-cyclotrimerization catalyst

Photolysis of [{(μ 3-BH)(Cp*Ru)Fe(CO) 3} 2(μ-CO)] (1; Cp* = η 5-C 5Me 5) in the presence of various alkynes such as 1,2-diphenylethyne, 1-phenyl-1-propyne, 2-butyne, and 1-(diphenylphosphino)-2-phenylacetylene led to the formation of four types of novel heterometallic metallacarboranes, [1,1,1-(CO) 3-μ-2,3-(CO)-2,3-(Cp*) 2-4,6-Ph 2-closo-1,2,3,4,6-FeRu 2C 2BH] (2), [1,8-(Cp*) 2-2,2,7,7-(CO) 4-μ-2,8-(CO)-μ-7,8- (CO)-4-Me-5-Ph-pileo-1,2,7,4,5-RuFe 2C 2(BH) 2] (3), [1,8-(Cp*) 2-2,2,7,7-(CO) 4-μ-2,8-(CO)-μ-7, 8-(CO)-4,5-Me 2-pileo-1,2,7,4,5-RuFe 2C 2(BH) 2] (4), and [1,2-(Cp*) 2-6,6,7,7-(CO) 4-μ-2,7-(CO)-exo-μ-5,6-(PPh 2)-μ 3-1,2, 6-(BH)-4-Ph-pileo-1,2,6,7,4,5-Ru 2Fe 2C 2BH] (5). Cluster compound 2 exhibits an octahedral structure with adjacent carbon atoms consistent with its skeletal electron pair (sep) count of 7. The cage geometry of 3 and 4 is based on a pentagonal bipyramid with one additional {Cp*Ru} vertex capping one of its faces. The solid-state X-ray diffraction results of 5 suggest that the core geometry is a capped pentagonal bipyramid, with an Fe-C bridging PPh 2 group. All the cluster compounds 2-5 have been characterized by IR and 1H, 11B, and 13C NMR spectroscopy, and the geometries of the structures were unequivocally established by crystallographic analysis. © 2012 American Chemical Society.

Organometallics

Synthesis and characterization of novel ruthenaferracarboranes from photoinsertion of alkynes into a ruthenaferraborane

The reaction of [CpnMCl4-x] (M=V: n=2, x=2; M=Nb: n=1, x=0; Cp=Î·5-C5H5) with LiBH4·THF followed by thermolysis in the presence of dichalcogenide ligands E2R2 (E=S, Te; R=2,6-(tBu) 2-C6H2OH, Ph) and 2-mercaptobenzothiazole (C7H5NS2) yielded dimetallaheteroboranes [{CpV(μ-TePh)}2(μ3-Te)BH·thf] (1), [(CpV)2(BH3S)2] (2), [(CpNb)2B 4H10S] (3), [(CpNb)2B4H 11S(tBu)2C6H2OH] (4), and [(CpNb)2B4H11TePh] (5). In cluster 1, the V2BTe atoms define a tetrahedral framework in which the boron atom is linked to a THF molecule. Compound 2 can be described as a dimetallathiaborane that is built from two edge-fused V2BS tetrahedron clusters. Cluster 3 can be considered as an edge-fused cluster in which a trigonal-bipyramidal unit (Nb2B2S) has been fused with a tetrahedral core (Nb2B2) by means of a common Nb2 edge. In addition, thermolysis of an in-situ-generated intermediate that was produced from the reaction of [Cp2VCl2] and LiBH 4·THF with excess BH3·THF yielded oxavanadaborane [(CpV)2B3H8(μ3- OEt)] (6) and divanadaborane cluster [(CpV)2B5H 11] (7). Cluster 7 exhibits a nido geometry with C2v symmetry and it is isostructural with [(Cp*M)2B 5H9+n] (M=Cr, Mo, and W, n=0; M=Ta, n=2; Cp*=Î·5-C5Me5). All of these new compounds have been characterized by 1H NMR, 11B NMR, and 13C NMR spectroscopy and elemental analysis and the structural types were established unequivocally by crystallographic analysis of compounds 1-4, 6, and 7. Group 5 alive: Divanadatellura- and divanadathiaboranes were obtained from the treatment of Group 5 metal polychlorides with dichalcogenides and monoboranes. The treatment of [Cp2VCl2] with monoboranes yielded an oxavanadaborane and a divanadaborane (see structures). Copyright © 2012 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Synthesis and structural characterization of new divanada- and diniobaboranes containing chalcogen atoms

C-H activation of arenes and heteroarenes has been achieved by a hydrogen rich tantalaborane cluster [(Cp*Ta)2B5H 11] that leads to the formation of C-H functionalized products. Furthermore, we examined the reaction of substituted thiophene and pyrrole derivatives with tantalaborane which provided a convenient and efficient route to regio-defined C-H functionalized heteroarenes. © 2011 The Royal Society of Chemistry.

Chemical Communications

C-H activation of arenes and heteroarenes by early transition metallaborane, [(Cp*Ta)2B5H11] (Cp* = η5-C5Me5)

Synthesis and structural characterization of diruthenium cluster containing germylene ligand

Journal	Data powered by TypesetJournal of Organometallic Chemistry
Publisher	Data powered by TypesetElsevier B.V.
ISSN	0022328X
Open Access	No