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Step‐by‐Step Uncoordination of the Pyrazolyl Rings of Hydrotris(pyrazolyl)borate Ligands in Complexes of Rh I and Rh III
Author(s) -
Paneque Margarita,
Sirol Sabine,
Trujillo Marianela,
Carmona Ernesto,
GutiérrezPuebla Enrique,
Monge M. Angeles,
Ruiz Caridad,
Malbosc François,
Berre C. SerraLe,
Kalck Philippe,
Etienne Michel,
Daran Jean Claude
Publication year - 2001
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 - 10.1002/1521-3765(20010917)7:18<3868::aid-chem3868>3.0.co;2-t
Subject(s) - rhodium , denticity , chemistry , boron , hydride , medicinal chemistry , ligand (biochemistry) , stereochemistry , crystallography , crystal structure , catalysis , organic chemistry , metal , biochemistry , receptor
Compounds of rhodium( I ) and rhodium( III ) that contain ancillary hydrotris(pyrazolyl)borate ligands (Tp′) react with monodentate and bidentate tertiary phosphanes in a step‐wise manner, with incorporation of P‐donor atoms and concomitant replacement of the Tp′ pyrazolyl rings. Accordingly, [Rh( κ 3 ‐Tp Me 2)(C 2 H 4 )(PMe 3 )] ( 1 b ), converts initially into [Rh( κ 2 ‐Tp Me 2)(PMe 3 ) 2 ] ( 3 ), and then into [Rh( κ 1 ‐Tp Me 2)(PMe 3 ) 3 ] ( 2 ) upon interaction with PMe 3 at room temperature, in a process which can be readily reversed under appropriate experimental conditions. Full disengagement of the Tp′ ligand is feasible to give Tp′ salts of rhodium( I ) complex cations, for example, [Rh(CO)(dppp) 2 ][Tp Me 2 ,4‐Cl ] ( 5 ; dppp=Ph 2 P(CH 2 ) 3 PPh 2 ), or [Rh(dppp) 2 ][Tp Me 2 ,4‐Cl ] ( 6 ). Bis(hydride) derivatives of rhodium( III ) exhibit similar substitution chemistry, for instance, the neutral complex [Rh(Tp)(H) 2 (PMe 3 )] reacts at 20 °C with an excess of PMe 3 to give [Rh(H) 2 (PMe 3 ) 4 ][Tp] ( 9 b ). Single‐crystal X‐ray studies of 9 b , conducted at 143 K, demonstrate the absence of bonding interactions between the [Rh(H) 2 (PMe 3 ) 4 ] + and Tp ions, the closest Rh ⋅⋅⋅ N contact being at 4.627 Å.