A close-packed boron-rich 11-vertex molybdaborane with novel geometry

Chakrahari, Kiran Kumar Varma; Thakur, Arunabha; Mondal, Bijan; Dhayal, Rajendra S.; Ramkumar, V.; Ghosh, Sundargopal

doi:10.1016/j.jorganchem.2012.02.027

Cited by 17 publications

(9 citation statements)

References 31 publications

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“…Although 11-vertex boron-rich clusters of Re, Ru, Co, and Rh, for example, [(Cp*Re) 2 B 9 H 9 ], [2,3-(Me) 2 -1-(η 6 -MeC 6 H 4 i Pr)- closo -1,2,3-RuC 2 B 8 H 8 ], [(PMe 3 )(PPh 3 )(OEt 2 )RuB 10 H 8 ], and [8,8,8-(PMe 3 ) 3 - nido -8,7-RhSB 9 H 10 ], are known, cluster 8 is the first iridaborane to be recognized with 11-vertex isocloso geometry. Note that [(Cp*Re) 2 B 9 H 9 ] ( I ) has a six-connected planar boron ring, whereas in [(Cp*M) 3 (μ-H)B 8 H 8 ], II and III (M = Mo, W), , the metal atoms are connected to the B 7 unit.…”

Section: Resultsmentioning

confidence: 99%

Hypoelectronic 8–11-Vertex Irida- and Rhodaboranes

et al. 2016

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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* = η(5)-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 (1)H, (11)B, and (13)C NMR spectroscopy in solution, and the solid-state structures were established by X-ray crystallographic analysis.

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Section: Resultsmentioning

confidence: 99%

Hypoelectronic 8–11-Vertex Irida- and Rhodaboranes

et al. 2016

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“…The 10-vertex Cp* 3 Rh 3 B 7 H 7 has a central Rh 3 B 7 isocloso deltahedron (Figure 1) with rhodium atoms located at the unique degree 6 vertex and two degree 5 vertices adjacent to the degree 6 vertex. 24 The 11-vertex Cp* 3 Co 3 B 8 H 7 R (R = H, Me; Cp* = η 5 -Me 5 C 5 ) 25 trimetallaboranes have a central Co 3 B 8 closo/isocloso deltahedron (Figure 1) with one cobalt atom at the unique degree 6 vertex and the other cobalt atoms at symmetry-equivalent degree 5 vertices situated to form a large, nearly equilateral Co 3 triangle (Figure 3). Other known trimetallaboranes include the 11-vertex hypoelectronic group 6 metal derivatives Cp* 3 M 3 (μ-H)B 8 H 8 (M = Mo, 26 W 27 ), which have been the subject of a recent theoretical study.…”

Section: Introductionmentioning

confidence: 92%

“…The 11-vertex Cp* 3 Co 3 B 8 H 7 R (R = H, Me; Cp* = η 5 -Me 5 C 5 ) trimetallaboranes have a central Co 3 B 8 closo/isocloso deltahedron (Figure ) with one cobalt atom at the unique degree 6 vertex and the other cobalt atoms at symmetry-equivalent degree 5 vertices situated to form a large, nearly equilateral Co 3 triangle (Figure ). Other known trimetallaboranes include the 11-vertex hypoelectronic group 6 metal derivatives Cp* 3 M 3 (μ-H)B 8 H 8 (M = Mo, W), which have been the subject of a recent theoretical study . Studying such polymetallaborane systems provides key information for understanding effects on preferred geometries and chemical reactivities as boron vertices in cluster structures are replaced by valence isoelectronic and isolobal transition-metal vertices.…”

Section: Introductionmentioning

confidence: 99%

Polyhedral Trimetallaboranes of the Group 9 Metals: Isocloso versus Capped and Uncapped Closo Deltahedra

2018

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The structures and energetics of the trimetallaboranes Cp 3 M 3 B n−3 H n−3 (Cp = η 5 -C 5 H 5 ; M = Co, Rh, Ir; n = 5−12) have been investigated by density functional theory. The capped-octahedral structures of the experimentally known 7-vertex trimetallaboranes (η 5 -R 5 C 5 ) 3 M 3 B 4 H 4 (R = H, M = Co; R = Me, M = Co, Rh, Ir) with the three degree 5 vertices occupied by metal atoms correspond to the lowest-energy structures by substantial margins. The lowest-energy structures for the 8-and 9-vertex Cp 3 M 3 B n−3 H n−3 (M = Co, Rh, Ir) systems have central closo deltahedra despite their 2n rather than the 2n + 2 skeletal electrons suggested by the Wade−Mingos rules for closo deltahedra. The lowest-energy structures for the 10-vertex Cp 3 M 3 B 7 H 7 as well as the experimentally known Cp* 3 Rh 3 B 7 H 7 have a central M 3 B 7 isocloso deltahedron with one of the metal atoms located at the unique degree 6 vertex. All of the low-energy 11-vertex Cp 3 M 3 B 8 H 8 (M = Co, Rh, Ir) structures, including the experimentally known Cp* 3 Co 3 B 8 H 8 , have a central M 3 B 8 closo/isocloso deltahedron with one of the metal atoms located at the unique degree 6 vertex. The central M 3 B 9 polyhedra in the lowest energy structures for the 12-vertex systems Cp 3 M 3 B 9 H 9 (M = Co, Rh, Ir) are not regular icosahedra but instead 12vertex deltahedra with two degree 6 vertices for two of the three metal atoms balanced by two degree 4 vertices. This deltahedron is derived from the regular icosahedron by a diamond−square−diamond transformation.

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“…In particular, following the pioneering work of Hawthorne et al [13], several groups such as those of Evans [14], Welch [15], Xie [16,17], and ours [18][19][20] have contributed in enriching the library of the large 12-16 vertex single cage polymetalla(hetero)borane clusters over the years. The already extensive array of metallaborane clusters continues to grow in direct proportion with the advent of novel synthetic methods [9,11,17,[21][22][23][24][25][26][27][28][29][30][31][32][33]. However, it is difficult to come up with an integrated scheme aimed at the synthesis of polyhedra bearing definite geometry and composition.…”

Section: Introductionmentioning

confidence: 99%

Metal-Rich Metallaboranes: Synthesis, Structures and Bonding of Bi- and Trimetallic Open-Faced Cobaltaboranes

et al. 2021

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Synthesis, isolation, and structural characterization of unique metal rich diamagnetic cobaltaborane clusters are reported. They were obtained from reactions of monoborane as well as modified borohydride reagents with cobalt sources. For example, the reaction of [Cp*CoCl]2 with [LiBH4·THF] and subsequent photolysis with excess [BH3·THF] (THF = tetrahydrofuran) at room temperature afforded the 11-vertex tricobaltaborane nido-[(Cp*Co)3B8H10] (1, Cp* = η5-C5Me5). The reaction of Li[BH2S3] with the dicobaltaoctaborane(12) [(Cp*Co)2B6H10] yielded the 10-vertex nido-2,4-[(Cp*Co)2B8H12] cluster (2), extending the library of dicobaltadecaborane(14) analogues. Although cluster 1 adopts a classical 11-vertex-nido-geometry with one cobalt center and four boron atoms forming the open pentagonal face, it disobeys the Polyhedral Skeletal Electron Pair Theory (PSEPT). Compound 2 adopts a perfectly symmetrical 10-vertex-nido framework with a plane of symmetry bisecting the basal boron plane resulting in two {CoB3} units bridged at the base by two boron atoms and possesses the expected electron count. Both compounds were characterized in solution by multinuclear NMR and IR spectroscopies and by mass spectrometry. Single-crystal X-ray diffraction analyses confirmed the structures of the compounds. Additionally, density functional theory (DFT) calculations were performed in order to study and interpret the nature of bonding and electronic structures of these complexes.

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A close-packed boron-rich 11-vertex molybdaborane with novel geometry

Cited by 17 publications

References 31 publications

Hypoelectronic 8–11-Vertex Irida- and Rhodaboranes

Hypoelectronic 8–11-Vertex Irida- and Rhodaboranes

Polyhedral Trimetallaboranes of the Group 9 Metals: Isocloso versus Capped and Uncapped Closo Deltahedra

Metal-Rich Metallaboranes: Synthesis, Structures and Bonding of Bi- and Trimetallic Open-Faced Cobaltaboranes

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