Chemistry of group 9 dimetallaborane analogues of octaborane(12)

Abstract

We report the synthesis, isolation and structural characterization of several moderately air stable nido-metallaboranes that represent boron rich open cage systems. The reaction of [Cp*CoCl]2, (Cp* = η(5)-C5Me5), with [BH3·thf] in toluene at ice cold temperature, followed by thermolysis in boiling toluene produced [(Cp*Co)B9H13], 1 [(Cp*Co)2B8H12], 2 and [(Cp*Co)2B6H10] 3. Building upon our earlier reactivity studies on rhodaboranes, we continue to explore the reactivity of dicobalt analogues of octaborane(12) cluster 3 with [Fe2(CO)9] and [Ru3(CO)12] at ambient conditions that yielded novel fused clusters [Fe2(CO)6(Cp*Co)2B6H10], 4 and [Ru4(CO)11(Cp*Co)2B3H3], 5 respectively. In an attempt to synthesize a heterometallic metallaborane compound we performed the reaction of [(Cp*Rh)2B6H10], 6 with [Cp*IrH4] that yielded a Ir-Ir double bonded compound [(Cp*Ir)2H3][B(OH)4], 7. All the new compounds have been characterized by IR, (1)H, (11)B, (13)C NMR spectroscopy, and the molecular structures were unambiguously established by X-ray diffraction analysis.

The presence of cobaltdibismuth triangular faces in the lowest energy deltahedral cobaltadibismaborane polyhedra: Major differences from their cobaltadiphosphaborane analogues

“…Such a synthesis of CpCoBi 2 B 9 H 9 would be analogous to the reported synthesis of Bi 2 B 10 H 10 from B 10 H 14 , BiCl 3 , and triethylamine [11]. In addition, similar reactions of the known [24] Cp*CoB 8 H 12 and Cp*CoB 9 H 13 (Cp* ¼ h 5 -Me 5 C 5 ) with BiCl 3 and a suitable amine could provide possible synthetic routes to the closely related permethylated derivatives Cp*CoBi 2 B 8 H 8 and Cp*CoBi 2 B 9 H 9 , respectively. Reactions of Bi 2 B 10 H 10 with reactive cobalt reagents such as CpCo(CO) 2 or CpCo(C 2 H 4 ) 2 might also provide synthetic routes to CpCoBi 2 B n H n derivatives.…”

Directed Syntheses of CS2- and CS3-Bridged Decaborane-14 Analogues

“…All chemicals, such as [LiBH 4 ·THF]; S, Se, and Te powders; CS 2 ; [Mo­(CO) 6 ]; and [W­(CO) 6 ] were purchased from Sigma-Aldrich and used without purification. Li­[BH 2 E 3 ] (E = S, Se, and Te), [(Cp*Co) 2 B 6 H 10 ], and [(Cp*Rh) 2 B 6 H 10 ] were prepared by following the literature procedures. The reaction mixtures were separated on dialuminum-supported TLC plates (MERCK TLC Plates).…”

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

“…Although, in most cases, the metallaboranes are generated in small yields with a low metal−to−boron ratio, it was the strategy that involved pyrolyzing [Cp*RhCl 2 ] 2 in large excess of [BH 3 •THF], that allowed us to isolate 15and 16-vertex rhodaborane clusters [18]. Although fused clusters [46] or single cage clusters bearing 5-11 vertices are reported with the cobalt system [20,[46][47][48][49][50][51][52], isolation of analogous single cage supraicosahedral cobaltaboranes has not been successful up until now despite the fact that both rhodium and cobalt are group-9 metals. Indeed, our recent reports include the formation of a range of high-nuclearity cobaltaborane clusters, such as the hypoelectronic 9-vertex closo-[(Cp*Co) 2 B 7 H 6 OMe], hypoelectronic octadecahedral 11-vertex closo-[(Cp*Co) 3 B 8 H 7 R] (R = H or Me), and icosahedral 12-vertex closo-[(Cp*Co) 3 B 8 H 8 S] species obtained from the reaction of [Cp*CoCl] 2 with [LiBH 4 •THF] and subsequent thermolysis with 2-mercaptobenzothiazole in toluene [50].…”

“…Group-9 metallaboranes have continually monopolized the field not only for novelty in geometries but also for the possibility to draw on the open cage molecules like [(Cp*M) 2 B 6 H 10 ] [M = Co and Rh] and [(Cp*Rh) 2 B 8 H 12 ] for further reactivities [53]. We have ourselves contributed significantly to this area by enriching the library of mono-and dicobaltadecaborane (14) analogues in the past [50][51][52]. Most recently, we have explored and reported the chemistry of dicobaltaoctaborane (12) with chalcogenated borohydride, Li[BH 2 E 3 ] [E = S, Se, or Te] which resulted in the characterization of novel chalcogenated analogues of dicobaltadecaborane (14) [54].…”