Preparation, properties, and reactions of metal-containing heterocycles: Part CV. Synthesis and structure of polyoxadiphosphaplatinaferrocenophanes

Abstract

A series of novel heterobimetallic crown ether-like polyoxadiphosphaplatinaferrocenophanes cis-[1,1′-Fc(CH 2O(CH 2CH 2O) n CH 2CH 2PPh 2) 2]PtCl 2 ( n=1–3) ( 4a– c) was synthesized in good yield by cyclization of the bis(phosphine) ligands 1,1′-Fc(CH 2O(CH 2CH 2O) n CH 2CH 2PPh 2) 2 ( n=1–3) ( 3a– c) and (PhCN) 2PtCl 2 under high dilution conditions in CH 2Cl 2. The bisphosphines 3a– c are obtained by reaction of the corresponding diols 1,1′-Fc(CH 2O(CH 2CH 2O) n CH 2CH 2OH) 2 ( n=1–3) ( 1a– c) with: (i) CH 3SO 2Cl in CH 2Cl 2 and (ii) LiPPh 2 in THF. Although the X-ray crystal structure of 4a shows that the cavity is large enough for the encapsulation of small metal cations, inclusion experiments of 4a– c with Group 1 cations, and Mg 2+, or NH 4 + in solution applying NMR titration and cyclovoltammetric methods reveal no evidence for the formation of host–guest complexes for 4a, b. In the case of 4c only the addition of Na + or K + leads to an insignificant effect.