Synthese und Kristallstruktur eines μ-Methylen-μ-hydrido-dialanats [R2Al(μ-CH2)(μ-H)AlR2]− (R = CH(SiMe3)2)

Synthesis and Crystal Structure of a μ-Methylene-μ-hydrido-dialanate [R₂Al(μ-CH₂)(μ-H)AlR₂]^? (R = CH(SiMe₃)₂) tert-Butyl lithium reacts with the recently synthesized methylene bridged dialuminium compound [(Me₃Si)₂CH]₂Al? CH₂? Al[CH(SiMe₃)₂]₂ 2 in the presence of TMEDA under β-elimination; the thereby formed hydride anion is bound in a chelating manner by both unsaturated aluminium atoms forming a 3c–2e–Al? H? Al bond. The crystal structure of the product shows two independent molecules differing only slightly in bond lengths and angles, but significantly in conformation. While one of the Al₂CH heterocycles deviates little from planarity with a rough C₂ symmetry for the whole anion, the other one is folded with an angle of 21.1° and the arrangement of the substituents is best described by C_s symmetry.     

Magnetic and Spectral Properties of Heterotrinuclear Acetates [Ru2Co(μ3-O)(μ-CH3CO2)6(Py)3]n+ (n = 0 or 1)

The preparation and physical properties of the new heterotrinuclear acetates, [Ru₂CO(μ₃-O)(μ-CH₃CO₂)₆(Py)₃] (Ru₂Co(II)) and [Ru₂Co(μ₃-O)(μ-CH₃CO₂)₆(Py)₃)l₃ (Ru₂Co(III), Py = pyridine), are reported. Three reversible one-electron-redox waves are observed at 1.19, 0.40, and ?1.24 V vs Ag/Ag⁺ electrode for Ru₂Co(lI) in CH₂Cl₂. The complexes of Ru₂Co(II) and Ru₂Co(III) show an intense visible absorption at 570 (? 5950 M^?1 cm^?1) and 551 nm (? 7240 M^?1 cm^?1), respectively. The magnetic susceptibilities of both complexes were also measured from 4.2 to 300 K. The resulting least-squares fit parameters for Ru₂Co(II) areJ_RuCo = ?9 cm^?1, J_RuRu = ?22 cm^?1, g_Co, = g_Ru= 2.19.