Date of Award
Doctor of Philosophy (PhD)
George G. Stanley
The synthesis and characterization of novel rhodium-tetraphosphine ligand complexes have been completed. The purpose of this dissertation research was to better characterize our novel binuclear hydroformylation catalyst by synthesizing and characterizing compounds with various combinations of rhodium centers and a binucleating tetratertiary phosphine ligand, et,ph-P4 [et,ph-P4 = (Et 2PCH2CH2)(Ph)PCH2P(Ph)(CH2CH 2PEt2)]. Eight new complexes, [Rh3(rac -et,ph-P4)2](BF4)3, 17, [Rh2(meso-et,ph-P4)2](PF6)2, 26, [Rh2(rac,meso-et,ph-P4)2](Cl) 2, 26a, [Rh2(rac-et,ph-P4) 2](BF4)2, 28, [RhCl2( rac-et,ph-P4)]BF4·toluene, 32a, [RhCl 2(rac-et,ph-P4)]BF4·MeOH, 32b, [RhCl2(rac-et,ph-P4)]BF4·2DCM, 32c, and [RhCl2(rac-et,ph-P4)]BF4 ·acetone, 32d, have resulted from these research efforts and are discussed in Chapters 2--4. 31P NMR analyses of these complexes show that none of these are present in our hydroformylation catalyst, based on in situ spectroscopic studies of [Rh 2(nbd)2(rac-et,ph-P4)]2+ by Dr. Rhonda Matthews. But, we believe that the cationic monometallic dihydride, [RhH2(4-rac-et,ph-P4)] +, is one of the complexes that does form in the bimetallic hydroformylation catalysis. Compounds 32a--32d are monometallic eta 4-coordinated complexes with two cisoidal chloride ligands and various solvent molecules. They are being studied as possible olefin polymerization catalysts. To be an effective catalyst, the octahedral complex will require at least one open coordination site on the metal. This will require the activation of the complex by the removal of a chloride (Cl-) ligand and the exchange of the other Cl- ligand with an alkyl group or hydride that can initiate or sustain polymerization. The results of these preliminary polymerization studies are also discussed.
Hunt, Clinton Jr, "Synthesis and Characterization of Novel Rhodium -Tetraphosphine Ligand Complexes." (2000). LSU Historical Dissertations and Theses. 7270.