Reactions of Diiminopyridine Ligands with Chalcogen Halides

The reactions of the chalcogen halides (Ch = S, Se, Te)
with a
series of diiminopyridine (DIMPY) ligands were explored. It was determined
through these studies that varying both the substitution on the α-carbon
and the chalcogen halide reagent afforded different products. If methyl
groups were present on the α-carbon, reactivity was observed
through the eneamine tautomer to yield N,N′,C-bound neutral chalcogen complexes. In the cases where H and C6H5 groups were in the same position, N,N′,N″-chelated chalcogen cations or dications were produced. Many of the
reactions resulted in complex mixtures postulated to occur by the
release of halogen decomposing the product or, for reactions with
the CH3 substituted ligand, uncontrollable reactivity with
the eneamine tautomer. This is the first report of reactions of sulfur
and selenium halides with the ubiquitous diiminopyridine ligands and
only the second example for a tellurium halide.

本研究对一系列二亚胺吡啶（diiminopyridine, DIMPY）配体与硫族卤化物（chalcogen halides，Ch = S、Se、Te）的反应进行了系统探究。经研究证实，改变α-碳上的取代基团以及所采用的硫族卤化物试剂类型，均可得到不同的反应产物。若α-碳上连有甲基，则反应通过烯胺互变异构体路径进行，最终生成N、N′、C配位的中性硫族配合物。当α-碳上同时存在氢与苯基取代基时，则会生成N、N′、N″螯合的硫族阳离子或二价阳离子配合物。多数反应会生成复杂混合产物，推测其成因主要有二：一是反应过程中释放的卤化物分解了目标产物；二是对于使用甲基取代配体的反应，烯胺互变异构体发生了不可控的副反应。本研究首次报道了硫卤化物、硒卤化物与普遍存在的二亚胺吡啶配体的反应，同时也是碲卤化物与该类配体发生反应的第二例相关案例。