Contemporary bimetallic molecules: an unusual class of exo-closo metallacarbaboranes having no metal–metal bonds

Silver Phosphanes Partnered with Carborane Monoanions: Synthesis, Structures and Use as Highly Active Lewis Acid Catalysts in a Hetero-Diels–Alder Reaction

“…[10] The silver phosphane fragment does not sit over the centre of this face but is more localised towards B (8) and the corresponding AgÀB bond lengths reflect this: Ag(1)ÀB(8) 2.504(1) ä, Ag(1)ÀB(12) 2.569(3) ä, Ag(1)ÀB(7) 2.619(2) ä. These bond lengths are broadly similar to those previously reported for the related complex [2,2,2-(CO) 3 -2-PPh 3 -7,12-{Ag(PPh 3 )}-closo-2,1-MoCB 10 H 9 ] [20,21] (2.552(4) ä and 2.589(4) ä), in which the Ag centre is bound dihapto by the cage and is the only other closo-polyhedral borane structure reported with an exo{AgPR 3 } fragment, although there are others reported with ligands other than phosphane, [22] with AgÀmetal bonds [21] and with endo coordination of a silver fragment. [18] The location of the silver phosphane fragment in relation to the B(8)ÀB (12) bond is such that the silver atom adopts a planar coordination motif with respect to P(1), B(8) and B (12) with the sum of relevant angles around Ag(1) 359.78.…”

“…Inspection of the extended lattice packing diagram shows that there are no Ag ¥¥¥ HÀB intermolecular interactions directed towards this vacant site. [18,20] However, there is a long intermolecular interaction (3. plane formed by B(8), B(12), Ag(1) and P (1). Although this distance is very long compared with other reported silverÀ arene bond lengths found in the solid-state structure of Ag carboranes (ca.…”

“…(3) Ag(1)ÀH (7) 2.51(2) Ag(1)ÀB (7) 3.494(2) P(1)ÀAg(1)ÀP (2) 130.90(1) Ag(1)ÀB(12)' 2.892(2) B(7)ÀAg(1)ÀB(12)' 72.4(6) Compound 3 Ag(1)ÀP (1) 2.4032(10) P(1)ÀAg(1)ÀBr (7) 117.44(3) Ag(1)ÀBr (7) 2.8710(5) P(1)ÀAg(1)ÀBr (8) 155.55(3) Ag(1)ÀBr (8) 2.6963(5) P(1)ÀAg(1)ÀBr (12) 93.31(3) Ag(1)ÀBr (12) 3.0953(5) P(1)ÀAg(1)ÀBr (11) Related metallaboranes with exo-coordinated {AgPPh 3 } fragments are also highly fluxional in solution. [20,21] We were initially surprised to observe that the 11 other systems. [25,44] Specifically, in the 11 B{ 1 H} NMR spectrum, resonances are observed at d À 10.3, d À 11.2 and d À 12.0 in the ratio 1:5:5.…”

Heterometallic Cluster Assembly on a Rhenium–Monocarborane Substrate

“…Moreover, cationic metal–ligand fragments react to give bimetallic species 3. 4 We have recently expanded our studies to non‐icosahedral metal–monocarborane complexes with the rhenacarborane ion 1 2− (Scheme ) 5. Herein we demonstrate that 1 2− may be used as a scaffold for the stepwise assembly of heteropolymetallic clusters.…”

Metal complexes of monocarbon carboranes bearing C-amine or -amino substituents

“…Nevertheless, it is reasonable to assume that the copper atom is bonded to a triangular B 3 face via three agostic-type B-H N Cu linkages. This is by analogy with the closely related species [2,2,2-(CO) 3 -2-PPh 3 -7,8,12-(l-H) 3 -7,8, 12-{Cu(PPh 3 )}-closo-2,1-MoCB 10 H 8 ] characterized by X-ray diffraction, which is obtained similarly from salts of the [2,2,2-(CO) 3 -2-PPh 3 -closo-2,1-MoCB 10 -H 11 ] À anion, and also does not reveal signals for the B-H N Cu linkages in its 1 H NMR spectrum [32].…”