Unprecedented Formation of the First Alkaline‐Earth‐Metal Complex Bearing an Asymmetrical gem‐Dithiolato Heteroscorpionato Ligand

Abstract

AbstractThe reaction of the lithium dithioacetate derivative [Li(bdmpzdta)(THF)] [bdmpzdta = bis(3,5‐dimethylpyrazol‐1‐yl)dithioacetate] with 1 equiv. of C3H5MgCl proceeds in high yield to give the first alkaline‐earth‐metal complex bearing an asymmetrical gem‐dithiolato moiety, namely, [Mg(κ3‐NNS‐μ‐S‐bppbte)]3 (1) [bppbte = 1,1‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)pent‐4‐ene‐2,2‐bis(thiolate)]. This is achieved through an unprecedented insertion reaction of the allyl group into the C=S bond. In contrast, the reaction with the Grignard reagents MeMgCl or EtMgCl leads to the formation of the six‐coordinate sandwich species [Mg(κ3‐bdmpzdta)2] (2), as a result of a rapid ligand redistribution. The molecular structures of 1 and 2 in the solid state have been unambiguously established by single‐crystal X‐ray diffraction studies, which reveal a trinuclear entity with a twisted six‐membered core for 1, in which all magnesium centers are arranged in a distorted trigonal bipyramidal geometry, whereas in 2 the magnesium center has an octahedral coordination environment with two heteroscorpionato ligands, which bind in a κ3‐NNS fashion with a relative trans disposition.