Complexes of 3,3'-Oxybis with Ni(II), Pd(II), Pt(II), Rh(I), and Ag(I). How Important is Backbone Rigidity in the Formation of trans-Spanning Bidentate Chelates ?

Article abstract of DOI:10.1002/hlca.19870700120

The bidentate diphosphine ligand, 3,3'-oxybis<(diphenylphosphino)methylbenzene> (1) forms monomeric, trans-square-planar complexes MX₂(1) (M = Ni, Pd, Pt; X = Cl^-, Br^-, I^-, and, in part, N₃^-, NCS^-, CN^-, NO₃^-) as well as Pt(H)Cl(1), Pt(H)Br(1) and RhCl(CO)(1).Polymeric species have been observed with substitutionally inert metal centres: trans-2(1)>₂ and cis-2(1)>_n (mean value of n ca. 4-5) 31P-NMR, and selected IR and UV/VIS parameters are reported.Ligand 1 shows a marked preference for trans-spanning and monomeric chelate formation, despite its various degrees of freedom of internal rotation in the ligand backbone.The readily available ligand 1 as well as analogues with other donor atoms, therefore, appear useful in most potential applications of trans-spanning chelate ligands.The crystal structure of AgCl(1)*0.5 (CH3)2C=O*0.39 C6H12 (space group C2/c, a = 21.02 Angstroem, b = 14.57 Angstroem, c= 24.79 Angstroem, β = 99.77 deg, V = 7531.4 Angstroem³, Z = 8) confirms the presence of three-coordinate Ag(I), with a coordination intermediate between a trigonal-planar and T-shaped geometry (P-Ag-P = 145.61(8) deg).