COMPLEXATION STUDIES WITH A CALIX[4]ARENE-DERIVED PHOSPHINITE - DIVERGENT ARRAYS OF CAVITIES LINKED BY MCL2 FRAGMENTS (M = PD, PT)

A cone-shaped calix[4]arene-derived monophosphinite, -di(ethoxycarbony lmethoxy)-26-hydroxy-28-(diphenyl phosphinooxy)calix[4]arene (Li), has been prepared in two steps from calix[4]arene. Treatment of L-1 with [AuCl(tetrahydrothiophene)] in tetrahydrofuran gave the phosphinite co mplex [AuClL1] (1). Reaction of [PdCl2(PhCN)(2)] with two equivalents of L-1 gave selectively trans-[PdCl2L21] (2). Complex 2.2 CH2Cl2 cryst allizes in the triclinic space group P (1) over bar. The molecule is c entrosymmetric, leading to a divergent array of the two calixarene moi eties. The palladium atom resides outside both cones. As a result of s teric interactions, the meta and para carbon atoms of the PPh2-bearing aryl ring are significantly pushed to the interior of the cavity. The related platinum complex trans-[PtCl2L21] (3), was obtained similarly from [PtCl2(PhCN)(2)] and presents in the solid state a structure whi ch is isomorphous to that of 2. The diphosphinite thoxy)-26,28-bis(dip henylphosphinoxy)calix[4]arene (cone) (L-2) has also been prepared and reacts with [PtCl2(PhCN)(2)] to yield oligomeric material.