Ferrocene Bis(phosphonite)s:  Synthesis and Characterization of a Novel Class of Sterically Congested Ligands¹

Chiral rhodium complexes containing bidentate ligands derived from (R,R)-1,2-diaminocyclohexane for catalytic enantioselective hydrosilylation of acetophenone

“…Very low intensity resonances were also present, but could not be identified. The addition of pyridine to the reaction mixture [9] formed the monomeric complex 5 supporting the assignment of a symmetrical chloro bridged dinuclear structure for complex 4. The two non-equivalent phosphorus atoms of the compound 5 display two doublets of doublets at δ = 142.0 ( 1 J P,Rh = 235 Hz; 2 J P,Rh,P = 67 Hz) and at δ = 151.8 ( 1 J P,Rh = 258 Hz; 2 J P,Rh,P = 67 Hz) in the 31 P{ 1 H} spectrum (C 6 D 6 ).…”

Coordination Chemistry and Asymmetric Catalysis with a Chiral Diphosphonite.

“…Although no further characterization was performed on this compound, the existence of this ABX pattern implies that the two phosphorus atoms are chemically inequivalent in the rhodium complex, as in the palladium case. The RhϪP coupling constant is similar to values reported by Börner, [13] Puddephatt, [26] and Shum, [27] although the latter report dealt with a Rh(acac)-diphosphonite derivative, with a 1 J Rh-P of 266 Hz.…”

Rhodium Complexes of Sterically Demanding Diphosphonites: Coordination Chemistry and Catalysis

“…The group of Pastor has reported a [Rh(acac)diphosphonite] complex. 31 Puddephatt has described the face-to-face dimer with a (CO)Rh-Cl-Rh(CO) core and the ligand (PhO) 2 PCH 2 P(OPh) 2 . 32 Their reported values for the Rh-Cl and Rh-P bond lengths are different compared to those found for complex 7, most likely due to the different electronic properties of the backbones used and the dimeric nature of their complex.…”

“…31 P{ 1 H} NMR (CDCl3) δ 163.9 (s, 1 J ) 191.5 Hz). FTIR (ATR mode, solid, cm -1 ): ν 1999 (Rh-(CO)).…”