Inorganic Chemistry, Vol.51, No.5, 3239-3246, 2012
New Superhindered Polydentate Polyphosphine Ligands P((CH2CH2PBu2)-Bu-t)(3), PhP((CH2CH2PBu2)-Bu-t)(2), P((CH2CH2CH2PBu2)-Bu-t)(3), and their Ruthenium(II) Chloride Complexes
The synthesis and characterization of the extremely hindered phosphine ligands, P((CH2CH2PBu2)-Bu-t)(3) ((PP3tBu)-P-2, 1), PhP((CH2CH2PBu2)-Bu-t)(2) (PhP(2)p(2)(tBu), 2), and P((CH2CH2CH2PBu2)-Bu-t)(3) ((PP3tBu)-P-3, 3) are reported, along with the synthesis and characterization of ruthenium chloro complexes RuCl2((PP3tBu)-P-2) (4), RuCl2((PhPP2tBu)-P-2) (5), and RuCl2((PP3tBu)-P-3) (6). The bulky (PP3tBu)-P-2 (1) and (PP3tBu)-P-3 (3) ligands are the most sterically encumbered PP3-type ligands so far synthesized, and in all cases, only three phosphorus donors are able to bind to the metal center. Complexes RuCl2((PhPP2tBu)-P-2) (5) and RuCl2((PP3tBu)-P-3) (6) were characterized by crystallography. Low temperature solution and solid state P-31{H-1} NMR were used to demonstrate that the structure of RuCl2((PP3tBu)-P-3) (4) is probably analogous to that of RuCl2((PP3tBu)-P-3) (5) which had been structurally characterized.