Synthese, Röntgenstrukturanalyse und katalytische Aktivität neuer Erdalkalimetall‐Alkinkomplexe

Synthesis, X‐ray Structures and Catalytic Activity of New Alkyne Complexes of the Alkaline Earth Metals Mg[N(SiMe 3 ) 2 ] 2 (THF) 2 ( 1 ) reacts with equal amounts of HC≡CPh and HC≡CSiMe 3 in THF yielding [(Me 3 Si) 2 NMgC≡CPh(THF)] 2 ( 2 ) and [(Me 3 Si) 2 NMgC≡CSiMe 3 (THF)] 2 ( 3 ), respectively. The reactions of (C 5 HMe 4 )MgBu ( 4 ), prepared in situ from Mg(C 5 HMe 4 ) 2 and MgBu 2 , with HC≡CPh and HC≡CSiMe 3 in THF afford [(C 5 HMe 4 )MgC≡CPh(THF)] 2 ( 5 ) and (C 5 HMe 4 )MgC≡CSiMe 3 (THF) 2 ( 6 ). The reaction of equivalent amounts of metallic Ca, C 5 H 2 Me 4 and HC≡CPh results in the formation of [(C 5 HMe 4 )CaC≡CPh(THF)] 2 ( 7 ). The 1 H and 13 C NMR spectra of the new compounds as well as the single‐crystal X‐ray structures of 3 , 5 , and 6 are reported and discussed. The alkyne complexes 3 , 5 , 6 , and 7 catalyze the polymerization of methylmethacrylate.