Self-Assembled Cyclophane-Type Copper(I) Complexes of 2,4,6-Tris(diphenylphosphino)-1,3,5-triazine and Their Catalytic Application

The
triazine-based trisphosphine, 2,4,6-tris­(diphenyl­phosphino)-1,3,5-triazine
(1) was prepared in improved yield by reacting cyanuric
chloride with 3 equiv of trimethylsilyldiphenylphosphine. The solid-state
structure of 1 showed short intermolecular P···P
contacts of 3.362 Å, which is significantly shorter than the
sum of the van der Waals radii of phosphorus atoms (3.6 Å). The
reaction of 2,4,6-tris­(diphenyl­phosphino)-1,3,5-triazine (1) with copper­(I) salts in a 2:3 molar ratio yielded various
cyclophane-type complexes in quantitative yield. The solid-state structures
of these clusters have been found to depend on the size of the halide
ions, the solvent employed, and the reaction conditions. Copper­(I)
chloride formed a monomeric metallocyclophane, whereas copper­(I) bromide
and copper­(I) iodide derivatives preferred dimeric and 1D-polymeric
structures, respectively. The tricationic complexes derived from CuI ion and 2,4,6-tris­(diphenyl­phosphino)-1,3,5-triazine
also adopted monomeric metallocyclophane structures. These complexes
have been employed in the A3 coupling reaction under microwave
irradiation. The copper­(I) iodide derivative showed excellent catalytic
efficiency.

以三嗪为骨架的三膦化合物2,4,6-三(二苯基膦基)-1,3,5-三嗪(2,4,6-tris(diphenylphosphino)-1,3,5-triazine，以下简称1)，通过氰尿酰氯与3当量的三甲基硅基二苯基膦反应，以提升后的收率制得。对该化合物的固态结构表征显示，其存在长度为3.362 Å的短程分子间P···P接触，该距离显著短于磷原子的范德华半径之和（3.6 Å）。将化合物1与铜(I)盐以2:3的摩尔比进行反应，以定量收率得到多种环番型配合物。研究发现，这类团簇的固态结构取决于卤离子尺寸、所用溶剂及反应条件：氯化亚铜会形成单金属环番结构，而溴化亚铜与碘化亚铜的衍生物则分别倾向于二聚体与一维聚合结构。由碘化亚铜与2,4,6-三(二苯基膦基)-1,3,5-三嗪衍生得到的三阳离子配合物，同样采用单金属环番结构。上述配合物已被应用于微波辐射条件下的A3偶联反应，其中碘化亚铜衍生物展现出优异的催化效能。