Crystal structures and spectroscopic properties of 2 lambda(3)-phospha-1,3-dionates and 1,3-dionates of calcium - Comparative studies on the 1,3-diphenyl and 1,3-Di(tert-butyl) derivatives
A hydrogen-metal exchange between dibenzoylphosphane and calcium carbide in tetrahydrofuran (THF) followed by addition of the ligand 1,3,5-trimethyl-1,3,5-triazinane (TMTA) furnishes the binuclear complex bis[(tmta-N,N',N")calcium bis(dibenzoylphosphanide)] (1a) co-crystallizing with benzene. Similarly, reaction of bis(2,2-dimethylpropionyl)phosphane with bis(thf-O)calcium bis[bis(trimethylsilyl)amide] in 1,2-dimethoxyethane (DME) gives bis(dme-0,0')calcium bis[bis(2,2-dimethylpropionyl)phosphanide] (1b) in high yield. The carbon analogues 1,3-diphenylpropane-1,3-dione (dibenzoylmethane) or 2,2,6,6-tetramethylheptane-3,5-dione (dipivaloylmethane) and bis(thf-O)calcium bis[tris(trimethylsilylmethyl)zincate] in DME afford bis(dme-O,O')calcium bis(dibenzoylmethanide) (2a) and the binuclear complex (mu-dme-O,O')-bis[(dme-O,O')calcium bis(dipivaloylmethanide)] (2b), respectively. Dialkylzinc formed during the metalation reaction shows no reactivity towards the 1,3-dionates 2a and 2b. Finally, from the reaction of the unsymmetrically substituted ligand 2-(methoxycarbonyl)cyclopentanone and bis(thf-O)calcium bis[bis(trimethylsilyl)amide] in toluene, the trinuclear complex 3 is obtained, co-crystallizing with THE The beta-ketoester anion bridges solely via the cyclopentanone unit.