Vibrational and H-NMR
spectroscopic studies on di-μ-chlorobis(1,5-cyclooctadiene) of iridium(I) and
rhodium (I) complexes have been carried out. In addition, the two D2h and D2 structures for both complexes have been fully optimized. It was expected from
the single-molecule vapor-phase density functional theory (DFT) calculation
that the D2 structure is more stable by 5 - 6 kcal/mol. While spectroscopic
analysis study confirms that in the solid phase, the two complexes retain the
higher D2h symmetry. The vibrational wavenumbers of certain modes associated to
free 1,5-cyc- looctadiene were observed to be shifted to lower values upon
coordination with rhodium or iridium metals. It was also found theoretically
that the metal-olefin interaction is slightly more pronounced for iridium
metal.？
References
[1]
Garcia, M.P., Millan, J.L. and Esteruelas, A. (1987) Rhodium (I) Complexes with the 2,2’-Bipyrimidine Ligand. 6, 1427-1431.
[2]
Masmarza, E., Sanau, M. and Peris, E. (2006) Synthesis and Reactivity of New Complexes of Rhodium and Iridium with Bis(dichloroimidazolylidene) Ligands. Electronic and Catalytic Implications of the Introduction of the Chloro Substituents in the NHC Rings. 12, 3063-3069.
[3]
Chen, T., Liu, X.-G. and Shi, M. (2007) Synthesis of New NHC-Rhodium and Iridium Complexes Derived from 2,2′-Diaminobiphenyl and Their Catalytic Activities toward Hydrosilylation of Ketones. Tetrahedron, 63, 4874-4880.
http://dx.doi.org/10.1016/j.tet.2007.03.150
[4]
Ibers, J.A. and Snyder, R.G. (1962) Crystal Structure of the Dimer of Rhodium Chloride 1,5-Cyclooctadiene. Acta Crystallogr, 15, 923-930. http://dx.doi.org/10.1107/S0365110X62002479
[5]
De Ridder, D.J.A. and Imhoff, P. (1994) Di-μ-chloro-bis[(cis,cis-η4-1,5-cyclooctadiene)rhodium(I)]: A Redetermination. Acta Crystallogr. Sect. C Cryst. Struct. Commun, 50, 1569-1572. http://dx.doi.org/10.1107/S0108270194001459
[6]
Cotton, F.A., Lahuerta, P., Sanau, M. and Schwotzer, W. (1986) Air Oxidation of Ir, (C1), (COD) 2 (Ruby Form) and Its Oxidation Product, Ir2C12 (COD) 2 (p2-OH) 2 (p2-0). Inorganica Chim. Acta, 120, 153-157.
http://dx.doi.org/10.1016/S0020-1693(00)86102-2
[7]
Barna, G.G. and Butler, I.S. (1978) Vibrational Spectra of 1,5-Cyclooctadiene, Di-μ-chlorobis[(1,5-cyclooctadiene) rhodium(I)], Di-μ-chlorobis[(1,5-cyclooctadiene)copper(I)] and Bis(1,5-cyclooctadiene)copper(I) Perchlorate. J. Raman Spectrosc., 7, 168-172. http://dx.doi.org/10.1002/jrs.1250070312
[8]
Wertz, D.W. and Moseley, M.A. (1980) Vibrational Study of the Metal-Olefin Bond in 1,5-Cyclooctadiene Complexes of Rhodium(I), Palladium(II), and Platinum(II). Inorg. Chem., 19, 705-708. http://dx.doi.org/10.1021/ic50205a025
[9]
Frisch, M.J., et al. (2009) Gaussian 09, Revision B. 01. Gaussian, Inc., Wallingford.
