Synthesis and Structure of Allyl and Alkynyl Complexes of Manganese(II) Supported by a Bulky <i>β</i>-Diketiminate Ligand^†

Reaction of LK (L = HC(CMeNAr)2, Ar = 2,6-iPr2C6H3) and MnCl2(THF)1.5 in THF unexpectedly resulted in the formation of the trinuclear complex LMn(μ-Cl)2Mn(THF)2(μ-Cl)2MnL (1) in good yield. The substitution reactions of 1 with C3H5MgCl and PhCCLi, respectively, provided the monomeric LMnC3H5(THF) (2) and the dimeric [LMn(μ-CCPh)]2 (3) in moderate yield. Complexes 1−3 were characterized by single-crystal X-ray structural analysis. The structures show that compound 1 contains an ideal planar Mn3Cl4 core and a linear Mn3 trimer, the allyl ligand in 2 is in an η1 mode, and there is π-interaction between the triple bond and the metal center in 3.