Reaction of [Cp*MoCl4] (Cp* = η5- C5Me5) with excess of [LiBH4·thf] followed by pyrolysis with NaI yielded B-I inserted [(Cp*Mo) 2B5H9-nIn], 1-3 (1: n = 1; 2: n = 2; 3: n = 3). In parallel to the formation of 1-3, the reaction also produced known [(Cp*Mo)2B5H9] and [(Cp*Mo)2(μ-I)4] in good yields. Under the similar reaction conditions, dimolybdathiaborane [(Cp*Mo) 2B4H4S2] yielded iodine substituted dimolybdathiaboranes, [(Cp*Mo)2B4S2H 4-nIn], 4 and 5 (4: n = 2; 5: n = 3) in good yields. All the new compounds have been characterized in solution by IR, 1H and 11B NMR as simple substituted derivatives of [(Cp*Mo) 2B5H9] and [(Cp*Mo)2B 4H4S2]. The solid state structures were established unambiguously by crystallographic analysis of compounds 1-5. © 2013 Elsevier B.V. All rights reserved.

Sundargopal Ghosh

Department Of Chemistry

boron

Organometallics

Synthesis (chemical)

11B NMR

CRYSTALLOGRAPHIC ANALYSIS

H-bonds

iodination

METALLABORANE CLUSTER

MOLYBDABORANE

Reaction conditions

Solid-state structures

halogenation

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 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

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.

Pure and Applied Chemistry

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

Density functional theory (DFT) has been used to probe the bonding and electronic properties of dimolybdaborane [(Cp*Mo)2B 5H9], 1 (Cp* = η5-C 5Me5), and several other heterodimolybdaborane clusters, such as [(Cp*Mo)2B5(μ3-OEt)H 7] (2), [(Cp*Mo)2B5(μ3-OEt) (n-BuO)H6] (3), [(η5-C5H5W) 2B4H4S2] (4), and [(Cp*Mo)2B4H4E2] (5-7, where, for 5, E = S, for 6, E = Se, and for 7, E = Te). The DFT results were also used to address some key points such as (i) the metal-metal bond length, (ii) the location and number of bridging and terminal hydrogen atoms, (iii) the molecular orbital analysis, and (iv) the assignment of 11B and 1H NMR chemical shifts. These studies further provide meticulous insight into similarities and differences between various dimetallaborane clusters 1-7. In addition, the crystal structures of 5 and 7 are reported, which come on top of the already existing literature of dimetallaboranes and support the theoretical findings. © 2012 American Chemical Society.

Inorganic Chemistry

Theoretical and experimental investigations on hypoelectronic heterodimetallaboranes of group 6 transition metals

Metal-rich metallaboranes: An exo-Fe(CO)3 moiety linked to a cubane core is the most prominent feature of complexes [(Cp*M) 2(μ3-E)2B2H(μ-H){Fe(CO) 2}2Fe(CO)3] (M=Mo, E=S, Se; M=Ru, E=CO; Cp*=n5-C5Me5), which are the first heterobimetallic cubane-type clusters with a boride unit (see structure). © 2011 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim.

Angewandte Chemie - International Edition

A family of heterometallic cubane-type clusters with an exo-Fe(CO) 3 fragment anchored to the cubane

Reaction of [1,2-(Cp*RuH)2B3H 7](1;Cp* = η-C5Me5) with [Mo(CO) 3(CH3CN)3] yielded arachno-[(Cp*RuCO) 2B2H6](2), which exhibits a butterfly structure, reminiscent of 7 sep B4H10. Compound 2 was found to be a very good precursor for the generation of bridged borylene species. Mild pyrolysis of 2 with [Fe2(CO)9] yielded a triply bridged heterotrinuclear borylene complex [(μ3-BH) (Cp*RuCO)2(μ-CO){Fe(CO)3}] (3) and bis-borylene complexes [{(μ3-BH)-(Cp*Ru)(μ-CO)}2Fe 2(CO)5](4) and [{(μ3-BH)(Cp*Ru)Fe(CO) 3}2(μ-CO)] (5). In a similar fashion, pyrolysis of 2 with [Mn2(CO)10] permits the isolation of μ3-borylene complex [(μ3-BH)-(Cp*RuCO) 2(μ-H)(μ-CO){Mn(CO)3}] (6) . Both compounds 3 and 6 have a trigonal-pyramidal geometry with the μ3-BH ligand occupying the apical vertex, whereas 4 and 5 can be viewed as bicapped tetrahedra, with two μ3-borylene ligands occupying the capping position. The synthesis of tantalum borylene complex [(μ3-BH)(Cp*TaCO) 2(μ-CO){Fe(CO)3}] (7) was achieved by the reaction of [(Cp*Ta)2B4H8(μ-BH4)] at ambient temperature with [Fe2(CO)9]. Compounds 2-7 have been isolated in modest yield as yellow to red crystalline solids. All the new compounds have been characterized in solution by mass spectrometry; IR spectroscopy; and 1H, 11B, and 13C NMR spectroscopy and the structural types were unequivocally established by crystallographic analysis of 2-6. © 2010 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Chemistry - A European Journal

From metallaborane to borylene complexes: Syntheses and structures of triply bridged ruthenium and tantalum borylene complexes

Reaction of (η5-C5Me5)MoCl4 with 6-fold excess of LiBH4·thf followed by pyrolysis with BHCl2·SMe2 in toluene at 90 °C yielded known (η5-C5Me5Mo)2B5H9 (1) and B-Cl inserted (η5-C5Me5Mo)2B5H8Cl (2), (η5-C5Me5Mo)2B5H7Cl2 (3-5, three isomers) and (η5-C5Me5Mo)2B5H5Cl4 (6). In addition, reaction of (η5-C5Me5Mo)2B5H9 with 5-fold excess of n-BuLi followed by excess of MeI in THF yielded B-Me inserted metallaboranes (η5-C5Me5Mo)2B5H7(CH3)2 (7, 8 two isomers) and (η5-C5Me5Mo)2B5H6(CH3)3 (9, 10 two isomers). Isolated yields of 2-6 are poor but 7-10 are modest to good. Compounds 2-10 can be viewed as bicapped closo trigonal bipyramidal geometry. All the new compounds have been characterized in solution by IR, 1H, 11B, 13C NMR and mass spectroscopy as simple substitution derivatives of (η5-C5Me5Mo)2B5H9 and the structural types were unequivocally established by crystallographic analysis of compounds 2, 3, 5 and 6. © 2008 Elsevier B.V. All rights reserved.

Substitution at boron in molybdaborane frameworks: Synthesis and characterization of isomeric (η5-C5Me5Mo)2B5HnXm (when X = Cl: n = 5, 7, 8; m = 4, 2, 1 and X = Me: n = 6, 7; m = 3, 2)

In addition to (η 5-C 5Me 5W) 25H 9, (η 5-C 5Me 5W) 3(μ-H)B 8H 8, and (η 5-C 5Me 5W) 2B 7H 9 reported earlier, thermolysis of {η 5-C 5Me 5 W}H 3B 4H 8 (1) with BH 3·THF leads to the formation of bicapped closo-{η 5C 5Me 5W} 2B 6H 10 (2) in parallel with a B-B linked djmer of {η 5-C 5Me 5W} 2B 5H 9 (4) and bis-{η 5-C 5Me 5W) 2B 5H 8} 2 (3). Reaction of 4 with a 3-fold excess of Fe 2(CO) 9 in hexane generates an iron analogue of 2, (η 5-C 5Me 5W) 2B 5H 9Fe(CO) 3 (5) in-46% yield. AU the metallaboranes, 2, 3, and 5, have been characterized by 1H, 11B NMR spectra and crystal structure determinations. The structures of 2 and 5 appear to follow the regular electron counting rules as they possess seven skeletal electron pairs (sep) appropriate for bicapped octahedral structures. However, their electronic structures revealed by a molecular orbital analysis is more closely related to that of [{η 5-C 5Me 5Re} 2B 7H 7], a cluster that does not obey the classical electron counting rules. Clusters 2 and 5 are notable examples of closo clusters containing four bridging hydrogens. 3 is a coupled-cage structure in which two bicapped trigonal bipyramidal frameworks, W 2B 5, are joined by an exopolyhedral boron-boron bond. © 2007 American Chemical Society.

Linked and fused tungstaborane clusters: Synthesis, characterization, and electronic structures of bis(η 5C 5Me 55W) 2B 5H 8} 2 and (η 5-C 5Me 55W) 2{Fe(CO) 3} n,B 6-nH 10-n, n = 0, 1

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