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Investigations into the Formation and Stability of Cationic Rhodium Diphosphane η 6 ‐Arene Complexes
Author(s) -
Fischer Christian,
Thede Richard,
Drexler HansJoachim,
König Anja,
Baumann Wolfgang,
Heller Detlef
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201201587
Subject(s) - rhodium , cationic polymerization , chemistry , chelation , catalysis , chemical stability , medicinal chemistry , polymer chemistry , inorganic chemistry , organic chemistry
Rhodium–η 6 ‐arene complexes can be generated in the presence of arenes following the hydrogenation of the diolefin in rhodium catalyst precursors of the type [Rh(PP*)(diolefin)]X (PP*=chelating diphosphane, X=noncoordinating anion). In this paper we report the characterization of such arene complexes with the ligands DuPhos, dipamp, dppe, Tangphos, dppf, and diop by means of NMR spectroscopy ( 31 P, 103 Rh) and X‐ray analysis. A procedure that follows the approach to equilibrium as a function of time monitored by using an UV/Vis diode array was used to determine 20 stability constants. Analyses were accomplished directly from the spectra by either a numeric and/or a new analytic solution of the underlying system of differential equations. Additionally thermodynamic parameters were determined in the temperature range between 278 and 318 K.