Mono and binuclear rhodium dicarbonyl complexes containing the hydridotris(3-p-chlorophenylpyrazol-1-yl)borate ligand (TpPhCl). X-ray structures of the binuclear complex [(OC)2Rh(μ:κ2,κ1-TpPhCl)Rh(Cl)(CO)2] and of three isomers of [Rh(κ2-TpPhCl)(CO)2]

Unexpected Influence of the Counteranion in the κ2vs κ3Hapticity of PolydentateN-Donor Ligands in [RhI(N-ligand)L2]+Complexes

“…Although the energy of the SP1 structure is close to the SPy one, it is not a minimum and evolves to the κ 3 one by rotating ∼90° around the B−C pz bond. Our results are in good agreement with the theoretical values previously reported 30 and also agree with the experimental results showing that two isomers can separately crystallize . The calculated energy differences between the SPy (κ 3 ) and SP1 (κ 2 ) forms of [Rh(Tp R )(CO) 2 ] complexes (14.7 kJ·mol -1 with Tp H and 10.2 kJ·mol -1 with Tp Me ligands, respectively) agree with the Δ H ° of 12.3 kJ·mol -1 estimated by spectroscopic methods for [Rh(Tp Ph )(CO) 2 ]…”

“…The X-ray structures of d 8 -[M(Tp R )L 2 ] where Tp R is hydridotris(1-pyrazolyl)borate, can be classified according to four basic geometries ( 2 ): two square-planar (SP) geometries with an uncoordinated third pyrazolyl nitrogen (one with the uncoordinated third pyrazolyl arm over the square-plane (SP1), and the other with an “inverted” boron (SP2)), a trigonal bipramidal (TBP) geometry with a κ 3 -Tp, and a square-pyramidal (SPy) geometry with the third pyrazolyl arm at an intermediate coordination with a long M−N bond. Each kind of structure can be stabilized by selecting a determined R-substituent for Tp ,, or L ligands. , Very recently the SPy, SP1, and SP2 forms of [Rh(Tp 3-R )(CO) 2 ] (R = p -C 6 H 4 Cl) have been isolated and characterized by X-ray diffraction . To our knowledge, this is the only compound with a (Tp R ) ligand that has been isolated and characterized in more than one isomeric form.…”

Reactions of Tris(oxazolinyl)phenylborato Rhodium(I) with C−X (X = Cl, Br, OTf) Bonds: Stereoselective Intermolecular Oxidative Addition

“…This {κ 2 -To M }Rh(CO) 2 is the first crystallographically characterized neutral (i.e., nonmethylated and nonprotonated), monovalent group 9 tris(oxazolinyl)borate compound. For comparison, tris(pyrazolyl)borato rhodium(I) compounds crystallize with tridentate and/or bidentate coordination geometries. ,− The crystallized structure contains a square-planar rhodium center (∑ L−Rh−L′ = 359.99°). The pendant, noncoordinated oxazoline blocks one face of the square-planar complex.…”