Synthesis and Coordination Chemistry of Water-soluble Phosphines: Application to Ru-Catalyzed Hydration of Nitriles in Aqueous and Biphasic Media

This dissertation investigates the synthesis and characterization of a series of 1,3,5-triaza-7-phosphaadamantane (PTA) derivatives and their ruthenium arene complexes as potential water-soluble catalysts for aqueous and biphasic hydration of nitrile. A series of upper-rim modified PTA derivatives were prepared by reaction of lithiated PTA with various electrophilic substrates, including aldehydes, ketones, imines and CO2. Monodentate ê1-P and bidentate ê2-P,O and P,N coordination modes were observed in Ru arene complexes of the newly synthesized phosphine ligands. Ruthenium arene complexes of â-aminophosphines PTA-CR1R2NHPh were synthesized and exhibited hemilabile behavior. All compounds were structurally characterized both in solution (multinuclear (1H, 13C, 31P) NMR spectroscopic studies, and ESI-MS) and in the solid state (IR, and single-crystal X-ray crystallography).The air-stable and water-soluble ruthenium arene complexes are active in catalytic hydration of nitriles to amides in water at 100 °C under air with tolerance toward ether, hydroxyl, nitro, bromo, aldehyde, pyridyl, benzyl, and alkyl functional groups. [RuCl2(PTA)4] is a highly active catalyst for aqueous nitrile hydration. Near quantitative conversion of aromatic, alkyl, and vinyl nitriles to their corresponding amides was observed. The reaction tolerated ether, hydroxyl, nitro, bromo, formyl, pyridyl, benzyl, alkyl, and olefinic functional groups. Some amides were isolated by simple decantation from the aqueous phase catalyst. Catalyst loading down to 0.001 mol% was examined with turnover numbers as high as 22000 observed. The catalyst was stable for weeks in solution and could be reused more than five times without significant loss of activity.Six group 12 metal complexes of PTA and derivatives, [ZnCl2(PTA)2], [ZnCl2(O=PTA)(H2O)], [ZnCl2(ì-O=PTA)]n, [HgCl2(ì-O=PTA)]n, [ZnCl2(S=PTAH)(S=PTAZnCl3)], and [CdCl2(S=PTA)(CH3OH)]n, have been synthesized, and characterized by IR, elemental analysis, ESI-MS, 1H and 31P{1H} NMR, and single-crystal X-ray analysis. Their structures and coordination modes are investigated both in the solid state and in aqueous solution. Their solid-state structures, found to be either dinuclear or polymeric, were elucidated by single-crystal X-ray diffraction. All the metal complexes, however, do not remain intact in aqueous solution as revealed by their 1H and 31P{1H} NMR spectroscopic data, and electrospray ionization mass spectrometry