Optically active transition metal complexes. Part 133. Preparation, epimerization and crystallization of chiral-at-metal rhodium(III) half-sandwich complexes

Syntheses, Structures, and Reactivity of New Pentamethylcyclopentadienyl-Rhodium(III) and -iridium(III) 4-Acyl-5-Pyrazolonate Complexes

“…The latter assumption is confirmed from their IR spectra, which exhibit bands from noncoordinated nitrate (10) and perchlorate groups (11). In both cases, the halide exchange is accompanied by coordination of a solvent molecule, consistent with the low tendency of Rh to coordinate NO 3 and ClO 4 groups.…”

Bis[2-(benzyliminomethyl)pyrrol-1-ido-κ2N,N′]bis(dimethylamido-κN)titanium(IV)

“…For the synthesis of N-[(pyrrol-2-yl)methylene]-1-phenylmethanamine, see: Brunner et al (1998); Joly & Jacobsen (2004); La Regina et al (2007). For the structures of related complexes, see: Li et al (2008); Brunner et al (2003); Simpson et al (2004); Wansapura et al (2003); Beer et al (2003).…”

“…The ligand N- [(pyrrol-2-yl)methylene]-1-phenylmethanamine can be synthesized by different methods (Brunner et al, 1998;Joly & Jacobsen, 2004;La Regina et al, 2007). This ligand has been used in the synthesis of a series of metalorganic complexes such as Ir(III) (Li et al, 2008), Rh(III) (Brunner et al, 2003), Pd(II) (Simpson et al, 2004), Cu(II) (Wansapura et al, 2003), Zn(II) and Ni(II) (Beer et al, 2003) by the reaction of the ligand with metal salts. Herein we report the synthesis and crystal structure of a titanium(IV) complex of this ligand.…”

NMR Studies of Optically Active Schiff Bases

“…Brunner et al [98][99][100] have published a series of papers on epimerisation of chiral rhodium(III) and iridium (III) half-sandwich complexes [39]. The kinetic studies of epimerisation were based on the integration of the signals at À 35, À 50 and À 65 C. The activation enthalpies and entropies were calculated.…”

“…For the complexes of (þ)-N-[(S)-1-phenylethyl]salicylaldimine, the interconversion of the possible diastereomers was too fast and the kinetic parameters were established from the coalescence at 21 C. The results have shown that rhodium complexes were more labile in the configuration at the metal centre than ruthenium ones. 98,99 Boehm et al 100 have synthesised and studied a series of half-sandwich rhodium (III) and iridium (III) complexes, derivatives of salicylaldehyde and L-amino acid esters. The diastereoselectivity has shown strong dependence on the type of metal as well as amino acid residue.…”