Stable “Inverse” Sandwich Complex with Unprecedented Organocalcium(I): Crystal Structures of [(thf)<sub>2</sub>Mg(Br)-C<sub>6</sub>H<sub>2</sub>-2,4,6-Ph<sub>3</sub>] and [(thf)<sub>3</sub>Ca{μ-C<sub>6</sub>H<sub>3</sub>-1,3,5-Ph<sub>3</sub>}Ca(thf)<sub>3</sub>]
收藏资源简介：
The reaction of bromo-2,4,6-triphenylbenzene with activated magnesium in THF yielded the Grignard reagent [(thf)2Mg(Br)-C6H2-2,4,6-Ph3] (1) with a Mg−C bond length of 214.8(3) pm. A similar reaction of bromo-2,4,6-triphenylbenzene with activated calcium led to an “inverse” sandwich complex [(thf)3Ca{μ-C6H3-1,3,5-Ph3}Ca(thf)3] (2) with the calcium atoms on opposite sides of the central arene ring showing small Ca−Ca′ and Ca−C distances of 427.9(3) and 259.2(3) pm. This extremely air- and moisture-sensitive complex exhibits thermochomic and solvatochromic behavior. It is paramagnetic with spin of S = 1 (triplet) with an ESR resonance at g = 2.0023. Quantum chemical calculations shed light on the bonding situation in this very unusual dinuclear Ca(I) compound.
