Synthesis and Complexation Behavior of the Functionalized Tripodal Phosphane cis,cis‐1,3,5‐Tris(cyano)‐1,3,5‐tris(diphenylphosphanyl)‐cyclohexane (tdppcycn)

Abstract

AbstractThe synthesis of the novel potentially bistripodal ligand cis‐cis‐1,3,5‐tris(cyano)‐1,3,5‐tris(diphenylphosphanyl)cyclohexane (tdppcycn) (6) is described. Starting from the tricarboxylic acid cis,cis‐1,3,5‐C6H9(COOH)3 (1), which is converted stepwise into the triacid chloride cis,cis‐1,3,5‐C6H9(COCl)3 (2), the triphenyl ester cis,cis‐1,3,5‐C6H9(COOPh)3 (3), the tricarboxamide cis,cis‐1,3,5‐C6H9(CONH2)3 (4), and the tricarbonitrile cis,cis‐1,3,5‐C6H9(CN)3 (5), we obtained tdppcycn (6) by α‐deprotonation of 5 followed by treatment with ClPPh2 in good yield. Treatment of 6 with Mo(CO)3(‐C7H8) and Ir(PPh3)2(CO)Cl gave octahedral Mo(tdpp‐cycn)(CO)3 (7) and pentacoordinate Ir(tdppcycn)(CO)Cl (8), respectively, with a facially P‐coordinated tdppcycn ligand. The stereochemistry of compounds 2–8 was established by 1H‐, 13C‐, 31P‐NMR, and IR spectroscopy. An X‐ray crystal structure analysis of complex 8 confirms the trigonal‐bipyramidal ground‐state structure in the solid state.