Synthesis and characterisation of a new class of phosphine-phosphonite ferrocenediyl dinuclear rhodium complexes

Bulky 1,1′-bisphosphanoferrocenes and their coordination behaviour towards Cu(i)

“…[25][26][27][28][29][30] Although many different 1,1′-symmetrically and unsymmetrically substituted bisphosphanoferrocenes have been reported in the past (B and C, Fig. 1), 19,23,25,[31][32][33][34][35][36][37][38][39][40] the catalytic discussions have been dominated by 1,1′-bis(diphenylphosphano)ferrocene (dppf, D, Fig. 1) for many decades.…”

“…Known symmetrically substituted dppf analogues (B): R = Me, 17 Et, 34 i Pr, 31,45 Cy, 19 t Bu, 32 o-tolyl, 33,46 o-MeO-C 6 H 4 , 34 p-MeO-C 6 H 4 , 47 p-PhO-C 6 H 4 , 46 p-CF 3 -C 6 H 4 , 48 3,5-CF 3 -C 6 H 3 , 33 2-furyl, 33 5-Me-2-furyl, 37 o-i Pr-C 6 H 4 , 34 1-Nap, 46 2-Nap, 46 C 6 F 5 . 34 Known 1,1'-unsymmetrically substituted dppf analogues (C): R = Ph, R' = t Bu; 35,36 R = Ph, R' = i Pr; 25 R = Ph, R' = Cy; 25 R = Ph, R' = p-MeO-C 6 H 4 ; 38 R = Ph, R' = 5-Me-2-furyl; 37 R = Ph, R' = Cl; 39 R = Ph, R' = OPh; 40 R = Ph, R' = OMen; 39 R = Ph, R' = p-Me-Ph; 38 R = p-Me-Ph, R' = p-CF 3 -Ph. 38 † Dedicated to Professor Manfred Scheer on the occasion of his 65th birthday.…”

An approach to bimetallic catalysts by ligand design

“…Complexes of this type require binucleating diphosphines with a large P-P distance. There are complexes consisting of mixed-metal assemblies where the diphosphine coordinates in the syn-form, [34][35][36] tetranuclear complexes with two units of halide bridged metal dimers in syn-form, 37,38 and dimetallacrown palladium ethers with the diphosphine chelating in both anti or syn-forms. 39,40 There are few examples of simple diphosphines capable of forming these kind of structures.…”

New concepts in multidentate ligand chemistry: effects of multidentarity on catalytic and spectroscopic properties of ferrocenyl polyphosphines

“…18) that present a rare ''quasiclose bridging'' A-frame are of interest on a fundamental level since only the dppf analogue was known prior to their synthesis. 10,30 Compounds 31 were synthesized from a dissymmetric phosphine-menthylphosphonite whereas in most of the dinuclear rhodium complexes reported; the metal centres present identical coordination spheres. Independent of the reaction, one may reasonably anticipate that cooperating effects would be more apparent from homodinuclear species presenting electronically and sterically different environments at the metal centres, as expected and observed in the heterodinuclear metal complexes.…”

“…However, the genuine monomeric or dimeric nature of the catalyst remain to be determined and the selectivity was poor. 10 Mononuclear rhodium complexes, such as 33, which incorporate other dissymmetric phosphine-phosphonite ligands, have been reported. 9 The activity of 34, obtained from a mixed bidentate (PLS) ferrocenyl ligand, and from which hemilability can be expected as well, was tested in the carbonylation of methanol without success.…”