New Superhindered Polydentate Polyphosphine Ligands P(CH2CH2PtBu2)3, PhP(CH2CH2PtBu2)2, P(CH2CH2CH2PtBu2)3, and their Ruthenium(II) Chloride Complexes
摘要:
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.
Newly designed and prepared molybdenum-nitride complexes bearing a mer-tridentate triphosphine as a ligand have been found to work as the most effective catalysts toward the catalytic reduction of dinitrogen to ammonia under ambient conditions, where up to 63 equiv of ammonia based on the Mo atom of the catalyst were produced.