Synthesis and Reactions of Enantiopure (Neomenthylcyclopentadienyl)iridium(III) Halides with Silver Salts. A Dramatic Steric Effect on the Competition between Inter- and Intramolecular C-H Activation

• Published in: Organometallics Vol. 13; no. 7; pp. 2548 - 2550
• Main Authors: Ma, Yinong, Bergman, Robert G
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.07.1994
• Subjects: 400102 - Chemical & Spectral Procedures; 400201 - Chemical & Physicochemical Properties; 400500 - Photochemistry; CHEMICAL ACTIVATION; CHEMICAL BONDS; CHEMICAL REACTIONS; Chemistry; CHLORIDES; CHLORINE COMPOUNDS; COMPLEXES; Condensed matter: structure, mechanical and thermal properties; DECOMPOSITION; ENANTIOMORPHS; Exact sciences and technology; HALIDES; HALOGEN COMPOUNDS; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IRIDIUM COMPLEXES; ISOMERS; MAGNETIC RESONANCE; NUCLEAR MAGNETIC RESONANCE; Organic chemistry; ORGANIC COMPOUNDS; ORGANOMETALLIC COMPOUNDS; Organometalloidal and organometallic compounds; PHOTOCHEMICAL REACTIONS; PHOTOLYSIS; Physics; Preparations and properties; RACEMATES; REACTION INTERMEDIATES; RESONANCE; RHODIUM COMPLEXES; SILVER COMPOUNDS; STEREOCHEMISTRY; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; SYNTHESIS; TRANSITION ELEMENT COMPLEXES; TRANSITION ELEMENT COMPOUNDS; Transition metals derivatives; Cationic complex; Iridium III Complexes; Iridium Organic compounds; Tertiary phosphine; Molecular structure; Rhodium Organic compounds; Organic ligand; Chiral compound; Transition metal Complexes; Trivalent metal Complexes; Experimental study; X ray diffraction; Hydrido complex; Rhodium III Complexes; Steric effect; Reaction mechanism; Silver Hexafluoantimonates; Platinoid Complexes; Iodo complex; Crystalline structure
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om00019a004

Reactions of enantiomerically pure (NMCp)M(PMe[sub 3])(Me)X complexes (NMCp = neomenthylcyclopentadientyl; M = Rh, Ir) have revealed that the 16-electron (NMCp)M(PMe[sub 3])(Me)[sup +] intermediates are achiral (planar) at the metal centers on the time average. Generation of the presumed intermediate (NMCp)Ir(PMe[sub 3]) by photolysis of (NMCp)Ir(PMe[sub 3])(H)[sub 2] in the presence of hydrocarbons results in intermolecular C-H activation. In contrast, the presumed intermediate (NMCp)M(PMe[sup 3])(Me)[sup +] exhibits only intramolecular C-H activation involving the neomenthyl group. One of these cyclometalation products has been structurally characterized. The different outcomes of these two systems are attributed to energy differences in the transition states based on molecular mechanics calculations. 26 refs., 1 fig.