First Evidence For Two Different μ-η1-η1- And μ-η1-η2- Co-ordination Modes Of The P3c2but 2 Ring Of [fe(η5-p3c2but 2)(η5-c5h5)] To A Same Cluster Fragment.

Abstract

Investigation of the solution structures of [Ir4(CO)11L] (L = [Fe(η5-P3C2But 2)(η5-C5H5)] (1) and [Fe(η5-P3C2But 2)(η5-P2C3But 3)] (2) by 13C and 31P NMR spectroscopy showed that, at 163K, 1 exists in the form of two isomers with bridged and non-bridged structures, in a 1:0.15 ratio, respectively, whereas 2 exists only in the bridged form. At RT, 1,2 shift of η5-P3C2But 2 ring was only observed for compound 2. Where as 2 loses CO readily in solution to give [Ir4(CO)10{μ-η1-η 1-[Fe(η5-P3C2But 2)(η5-P2C3But 3)}] (3), activation with Me3NO was necessary to produce [Ir4(CO)10{[Fe(η5-P3C 2But 2)(η5-C5H 5)}] (4), obtained in the form of two non-interconverting isomers 4a and 4b, which were not able to be separated. A single crystal X-ray diffraction study of isomer4a established that the [Fe(η5-P3C2But 2)(η5-C5H5)] ligand bridges one of the edges of the Ir4 tetrahedron, interacting via the lone electron pair of one of the adjacent P atoms and in an η2- mode via the P-P double bond of the η5-P3C2But 2 ring and that all CO ligands arc terminally bonded. Variable temperature31P{1H} NMR spectroscopy evidenced a fluxional process involving interactions between the Ir1 and Ir2 atoms and the lone pair on P1, the P1-P2 bond, and the lone pair on P2. According to multinuclcar NMR, cluster 4b has similar structure to compound 3, with the η5-P3C2But 2 ring co-ordinated in aη1-η1- mode via the two adjacent P atoms, and all CO ligands bonded terminally.114405411Dillon, K.B., Mathey, F., Nixon, J.F., (1998) Phosphorus the Carbon Copy, , John Wiley and Sons, Chichester, and references cited thereinBartsch, R., Hitchcock, P.B., Nixon, J.F., (1988) J. Organomet. Chem., 340, pp. C37Müller, C., Bartsch, R., Fischer, A., Jones, P.G., Schmutzler, R., (1996) J. Organomet. Chem., 512, p. 141Müller, C., Bartsch, R., Fischer, A., Jones, P.G., (1993) Polyhedron, 12, p. 1383Bartsch, R., Gelessus, A., Hitchcock, P.B., Nixon, J.F., (1992) J. Organomet. Chem., 430, pp. C10Callaghan, C.S.J., Hitchcock, P.B., Nixon, J.F., (1999) J. Organomet. Chem., 584, p. 87Müller, C., Bartsch, R., Fischer, A., Jones, P.G., (1993) J. Organomet. Chem., 453, pp. C16Bartsch, R., Gelessus, A., Hitchcock, P.B., Nixon, J.F., (1992) J. Organomet. Chem., 430, pp. C10Benvenutti, M.H.A., Hitchcock, P.B., Nixon, J.F., Vargas, M.D., (1996) Chem. Commun., 441Benvenutti, M.H.A., Hitchcock, P.B., Nixon, J.F., Vargas, M.D., (1996) J. Chem. Soc. Dalton Trans., p. 739Weber, L., Sommer, O., Stammler, H.-G., Neumann, B., Kölle, U., (1995) Chem. Ber., 128, p. 665Ajulu, F.A., Bartsch, R., Carmichael, D., Johnson, J.A., Jones, C., Matos, R.M., Nixon, J.F., (1995) Phosphorus-31 NMR Spectral Properties in Compound Characterisation and Structural Analysis, pp. 229-242. , Eds Quin, L. D. and Vekade, J. G., VCH, Weinheim, ch. 18Braga, D., Grepioni, F., Byrne, J.J., Calhorda, M.J., (1995) J. Chem. Soc. Dalton Trans., p. 3287Besançon, K., Laurenczy, G., Lumini, T., Roulet, R., Gervasio, G., (1993) Helv. Chim. Acta, 76, p. 2926. , and references cited thereinLumini, T., Laurenczy, G., Roulet, R., Tassan, A., Ros, R., Schenck, K., Gervasio, G., (1998) Helv. Chim. Acta, 81, p. 781Churchill, M.R., Hutchinson, J.P., (1978) Inorg. Chem., 17, p. 3528Benvenutti, M.H.A., Vargas, M.D., Braga, D., Grepioni, F., Parisini, E., Mann, B.E., (1993) Organometallics, 12, p. 2955Ros, R., Scrivanti, A., Albano, V.G., Braga, D., Garlaschelli, L., (1986) J. Chem. Soc. DaltonTrans., p. 2411Detzel, M., Friedrich, G., Scherer, O.J., Wolmershäuser, G., (1995) Angew. Chem. Int. Ed. Engl., 34, p. 1321Ros, R., Scrivanti, A., Albano, V.G., Braga, D., Garlaschelli, L., (1986) J. Chem. Soc. DaltonTrans., p. 2411Laurenczy, G., Bondietti, G., Ros, R., Roulet, R., (1996) Inorg. Chim. Acta, 247, p. 65. , and references cited thereinBartsch, R., Hitchcock, P.B., Nixon, J.F., (1987) J. Chem. Soc. Chem. Commun., p. 1146Binger, P., Glaser, G., (1994) J. Organomet. Chem., 479, pp. C28Chini, P., Ciani, G., Garlaschelli, L., Manassero, M., Martinengo, S., Sironi, A., Canziani, F., (1978) J. Organomet. Chem., 152, pp. C3