Dimerization of β-Diketiminato Calcium Complexes through Dihapto-Acetylide Ligation

The “selective” protonolysis of the β-diketiminato calcium derivative [Ca{(NDippCMe)2CH}{N(SiMe3)2}(THF)] (Dipp = C6H3iPr2-2,6) with a selection of terminal alkynes has produced a series of dimeric acetylides [Ca{(NDippCMe)2CH}{μ-C⋮CR}]2, which have been characterized in solution and in the solid state. The asymmetry of the Ca−C−Ca‘ bridges is subtly dependent upon the extent of “side-on” (π-type) interaction between the acetylide unit and the Ca‘ centers.