905445-22-9Relevant academic research and scientific papers
Hyperelectronic metal-carborane analogues of cymantrene (MnCp(CO) 3) anions: Electronic and structural noninnocence of the tricarbadecaboranyl ligand
Nafady, Ayman,Butterick III, Robert,Calhorda, Maria Jose,Carroll, Patrick J.,Chong, Daesung,Geiger, William E.,Sneddon, Larry G.
, p. 4471 - 4482 (2008/10/09)
The reduction of 1,1,1-(CO)3-2-Ph-c/oso-1,2,3,4-MnC 3B7H9, 1, to the hyperelectronic dianion 1 2- has been studied by electrochemistry, spectroscopy, X-ray crystallography, and DFT calculations. Depending on the medium, this cymantrene derivative displays either a single two-electron wave or two separate one-electron waves in cyclic voltammetry scans, always at potentials (e.g., E1/2 = -1.14 V vs ferrocene for 1/1- in THF) that are very far positive of that reported for MnCp(CO)3 (-2.86 V). Reduction of the corresponding Re compound 2 occurs in a single two-electron process. Both 1- and 12- were isolated as their decamethylcobaltocenium salts and characterized by X-ray crystallography. The hapticity of the tricarbadecaboranyl ligand is reduced from hexahapto (η6) in 1 to tetrahapto (η4) in 12-, mimicking an η5/η3 haptotropic rearrangement of a cyclopentadienyl ligand. The dianion 12- retains coordination to the C7-B3-B4-C9 face of the tricarbadecaboranyl ligand, much like that found previously for the neutral isocyanide adduct (CNBut)(CO) 3MnC3B7H9, 3, showing that the metal-ligand bonding reacts similarly to gain of either two electrons or an electron pair donor. The monoanion I- also shows ligand slippage to an η4 coordination in which relevant distances and angles are roughly intermediate of 1 and 12-. The SOMO of 1- is highly delocalized over the Mn-C3B7 framework. Although the tricarbadecaboranyl anion has a strongly electron-accepting ligand effect, the majority of the stabilization energy it imparts to nominally hyperelectronic metals originates from its flexibility in hapticity changes. By analogy to well-documented metal-chelate chemistry, the tricarbadecaboranyl group behaves as a noninnocent ligand in these electron-rich systems.
Chemistry of mangana- and rhenatricarbadecaboranyl tricarbonyl complexes: Evidence for an associative mechanism of ligand substitution involving an η6-η4 cage-slippage process analagous to η5-η3-cyclopentadienyl
Butterick III, Robert,Ramachandran, Bhaskar M.,Carroll, Patrick J.,Sneddon, Larry G.
, p. 8626 - 8637 (2007/10/03)
The reaction of the tricarbadecaboranyl anion, 6-Ph-nido-5,6,9-C 3B7H9-, with M(CO)5Br [M = Mn, Re] or [(η6-C10H8)Mn(CO) 3+]BF4-
