103Rh Chemical Shifts in Complexes Bearing Chelating Bidentate Phosphine Ligands

Autor:	Wolfgang Baumann, Carl Krüger, Roland Fornika, Magnus Kessler, Anna Rufińska, Michael Bühl, Eckhard Dinjus, Christian Six, Walter Leitner
Rok vydání:	1999
Předmět:	Denticity Chemistry Ligand Chemical shift Organic Chemistry Inorganic chemistry chemistry.chemical_element Nuclear magnetic resonance spectroscopy Systematic variation Rhodium Inorganic Chemistry Crystallography chemistry.chemical_compound Chelation Physical and Theoretical Chemistry Phosphine
Zdroj:	Organometallics. 18:1196-1206
ISSN:	1520-6041 0276-7333
DOI:	10.1021/om980980k
Popis:	Experimental and theoretical methods have been employed to investigate the influence of the chelating phosphine ligand on the 103Rh chemical shift in complexes containing the [(P2)Rh] fragment (P2 = chelating bidentate phosphine). The δ(103Rh) values obtained by 2D(31P,103Rh{1H}) NMR spectroscopy for a series of neutral rhodium complexes [{R2P(CH2)nPR2}Rh(hfacac)] (R = Ar, Ph, Cy, Me, n = 1−4, hfacac = hexafluoroacetylacetonate) have been compared. Systematic variation of the phosphine ligand has allowed separation of electronic and geometrical effects. The purely electronic influence of para substituents in complexes [{(p-XC6H4)2P(CH2)4P(p-XC6H4)2}Rh(hfacac)] correlates directly with the Hammett σP constants of X, but leads to variations in the chemical shift of less than 80 ppm between X = CF3 and X = OMe. In contrast, geometrical changes in complexes [(P2)Rh(hfacac)] lead to variations in the chemical shift over a range of approximately 800 ppm. The individual contributions of various structural parame...
Databáze:	OpenAIRE
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