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Solution structures of [IrH 2 (1,5‐cyclooctadiene) (bisphosphine)](CF 3 SO 3 ) complexes. Homo‐ and heteronuclear long‐range couplings from hydride and phosphorus spins to cyclooctadiene protons
Author(s) -
Hälg Werner J.,
Öhrström Lars R.,
Rüegger Heinz,
Venanzi Luigi M.
Publication year - 1993
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260310714
Subject(s) - chemistry , heteronuclear molecule , pseudorotation , 1,5 cyclooctadiene , hydride , stereochemistry , crystallography , cyclooctadiene , computational chemistry , nuclear magnetic resonance spectroscopy , molecule , organic chemistry , hydrogen , catalysis
The solution structures of the two all‐ cis stereoisomers of [IrH 2 (COD)((−)‐chiraphos)](CF 3 SO 3 ) and the four all‐ cis stereoisomers of [IrH 2 (COD)((−)‐norphos)](CF 3 SO 3 ) [COD = cycloocta‐1,5‐diene, (−)‐chiraphos = 2 S ,3 S ‐bis(diphenyl‐ phosphino)butane, (−)‐norphos = 2 R ,3 R ‐bis(diphenylphosphino)norbornene] were assigned on the basis of various one‐ and two‐dimensional correlation methods. The rationalization of a specifically observed scalar coupling interaction between one of the hydrides and a methylene proton of the cyclooctadiene moiety required an assignment of all the relevant protons including their stereochemical relationship. Analogous long‐range coupling pathways were also found for the heteronuclear interactions n J (P,H) and an interpretation of the origin of these scalar couplings is provided in the form of an expansion of the known geometric dependence of allylic and homoallylic couplings.