Synthesis, structure, and solution dynamics of indenyl rhodium complexes containing bulky phosphine ligands: molecular structures of (<font face="SYMBOL">h</font><sup>5</sup>-1-CH<sub>3</sub>-C<sub>9</sub>H<sub>6</sub>)Rh(<font face="SYMBOL">h</font><sup>2</sup>-C<sub>2</sub>H<sub>4</sub>)(PCy<sub>3</sub>) (Cy = cyclohexyl) and (<font face="SYMBOL">h</font><sup>5</sup>-1-CH<sub>3</sub>-C<sub>9</sub>H<sub>6</sub>)Rh(dcpe) (dcpe = Cy<sub>2</sub>PCH<sub>2</sub>CH<sub>2</sub>PCy<sub>2</sub>)
摘要:
Reactions of (eta(5)-1-CH3-C9H6)Rh(eta(2)-C2H4)(2) with PCy3 (Cy = cyclohexyl) acid 1,2-bis(dicyclohexylphosphino)ethane (dcpe = Cy2PCH2CH2PCy2) gave complexes (eta(5)-1-CH3-C9H6)Rh(eta(2)-C2H4)(PCy3) (1) and (eta(5)-1-CH3-C9H6)Rh(dcpe) (2), respectively, in high yields. Complexes 1 and 2 were characterized by x-ray diffraction studies and by multinuclear NMR spectroscopy. Variable temperature P-31{H-1} NMR spectra allowed for evaluation of energy barriers associated with indenyl ring rotation. While 1 and 2 displayed similar degrees of slip-fold distortion with respect to bonding of the indenyl ligand to the RhL2 fragment, a lower energy barrier to ring rotation was calculated for the mixed ethylene-phosphine complex 1. Yellow crystals of 1 are orthorhombic, Pbca with 16 molecules per unit cell of dimensions a = 11.341(3), b = 32.915(10), and c = 29.413(9) Angstrom. Yellow crystals of 2 are triclinic, PT with two molecules per unit cell dimensions a = 9.327(3), b = 10.117(3), c = 18.934(6) Angstrom, alpha = 104.28(2)degrees beta = 101.34(2)degrees and gamma = 92.99(2)degrees.