SYNTHESIS AND COMPLEXATION BEHAVIOR OF THE FUNCTIONALIZED TRIPODAL PHOSPHANE S(CYANO)-1,3,5-TRIS(DIPHENYLPHOSPHANYL)CYCLOHEXANE (TDPPCYCN)

The synthesis of the novel potentially bistripodal ligand s(cyano)-1,3 ,5-tris(diphenylphosphanyl)cyclohexane (tdppcycn) (6) is described. St arting from the tricarboxylic acid cis,cis-1,3,5-C6H9(COOH)(3) (1), wh ich is converted a stepwise into the triacid chloride cis,cis-1,3,5-C6 H9(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 tricarbo nitrile cis,cis-1,3,5-C6H9(CN)(3) (5), we obtained tdppcycn (6) by alp ha-deprotonation of 5 followed by treatment with ClPPh(2) in good yiel d. Treatment of 6 with Mo(CO)(3)(eta(6)-C7H8) and Ir(PPh(3))2(CO)Cl ga ve octahedral Mo(tdppcycn)(CO)(3) (7) and pentacoordinate Ir(tdppcycn) (CO)Cl (8), respectively, with a facially P-coordinated tdppcycn ligan d. The stereochemistry of compounds 2-8 was established by H-1-, C-13- , P-31-NMR, and IR spectroscopy. An X-ray crystal structure analysis o f complex 8 confirms the trigonal-bipyramidal ground-state structure i n the solid state.