[Pi]-conjugated materials containing transition metals

Autor: Clot, Olivier
Jazyk: angličtina
Rok vydání: 2001
Druh dokumentu: Text
Popis: In this thesis, the factors influencing the metal and organic fragment interactions in metal-containing conjugated polymers are investigated. All the compounds presented in this work were fully characterized by ¹H, ³¹P NMR, infrared and UV-visible spectroscopies. In Chapter 2, the syntheses and properties of trans,trans,trans-[Ru(PBu₃)₂(CO)(L)(C≡CFc)₂] (41, L = CO; 42, L = pyridine; 43, L - P(OMe)₃; Fc = ferrocenyl), trans, trans, trans-[RuCl₂(POMe-P)₂(FcC₆H₄NC)₂] (44) (POMe = PPh₂ C₆H₄OCH₃), trans, trans, trans RuCl₂(PC2Me-P)₂(FcC₆H₄NC)₂] (45) (PC2OMe = PPh₂ CH₂CH₂OCH₃) and the mixed carbonyl-isocyanide complexes trans, trans, trans--[RuCl₂(POMe-P)₂(CO)FcC₆H₄NC)] (46) and trans, trans, trans-[RuCl₂(PC2OMe-P)₂(CO)(FcC₆H₄NC)] (47) are described. Cyclic Voltammetry studies of 41-45 reveal that the ruthenium bisacetylide bridges in complexes 41-43 allow electronic interaction between the terminal ferrocenyl groups and the interaction depends on the nature of the ancillary ligands on the ruthenium. In contrast, no electronic interaction occurs between the ferrocenyl groups and the Ru centers in 44 and 45. A series of phosphine-thiophene ligands (51-55) offering several coordination site combinations have been prepared and are described in Chapter 3. Compounds 51 (dpppth), 52a (dppterth), 52b (Me-dppterth) and 52c (Me₂-dppterth) are found to bind to metals in a mono- or bidentate fashion (P or P,S). Compound 53 (5dppterth) can only be monodentate via the phosphine while compounds 54 and 55 can bind either in a bidentate (P₂ or P,S) or monodentate fashion via one phosphine only. Ruthenium(II) complexes [RuCl₂(dpppth-P,S)₂] (61), [RuCl₂ (dppterth-P,S¹)₂] (62) and [RuCl₂(CO) (5dppterth-P)₂] (71) are described in Chapter 4. Displacement of one of the dppterth ligands in 62 with bis(diphenylphosphino)methane (dppm) yields 66 which isomerizes in solution to 67. Complexes 61, 62, 66 and 67 react with carbon monoxide by displacing the coordinated thiophene. Complex 71 electropolymerizes to form red, conductive films whichwere characterized by energy dispersive X-ray (EDX), surface-reflectance IR and UV-visspectroscopies .Dinuclear complexes [Pd₂(µ,-Cl₂)(L)₂] (72a-c) (L= 52a-c) have been prepared in which the palladium centers are in a square planar geometry and the phosphine-thiophene ligand binds via the phosphorus and a carbon of a terminal thiophene ring. This work is described in Chapter5. Bis(phosphine) Pd(II) complexes (73a-c and 78) have been prepared with the ligands 52a-c and 53 and the monocationic complexes 74a-c have been synthesized from compounds 73a-c bychloride abstraction. In complexes 74a-c, the two phosphine-thiophene ligands are inequivalent. One is bound in a P,C fashion via a C of the terminal thiophene while the other is bound in a P,S fashion via an η¹ sulfur. Complexes 72a, 73a, 74a-b and 78 all electropolymerize to yield conductive polymer films which were characterized as described for 71. Palladium(II) complexes (80 and 81) have been prepared using the chelatingbis(phosphino)thiophene ligands 54 and 55. The complexes are square planar with the ligandscoordinated in a bidentate P₂ fashion. 4-Ferrocenylphenyl isocyanide (83) and 11-mercaptoundecanoyl ferrocene (84) spontaneously adsorb on Cr from CH₂Cl₂ solution. The modified surfaces are characterized bycyclic voltammetry, and the surface coverage was determined to be less than one monolayer. Immersion of the adsorbed layers into solution results in desorption. Iridium(I) complexes [IrCl(CO)(L)₂] 91 (L= dppterth) and 92 (L= 5dppterth) have been prepared and shown to react with oxygen to yield the O₂ adducts [IrCl(CO)(O₂)(L)₂]. Complexes 91 and 92 electropolymerize, however, the Ir center was found to be unstable under the polymerization conditions.
Science, Faculty of
Chemistry, Department of
Graduate
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