Date of Award

1994

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

Keywords

Chemistry, Inorganic.

Supervisor

Loeb, Stephen J.,

Rights

info:eu-repo/semantics/openAccess

Abstract

This thesis deals with the synthesis and characterization of several Ag(I), Rh(I), Ir(I), and Ru(II) complexes of tridentate crown thioether ligands. The incorporation of a rigid xylyl group into the macrocyclic backbone causes the ligand 2,5,8-trithia- (9) -o-cyclophane, TT (9) OC, to have an exodentate conformation in its free state, although the increased ring strain inherent in the o-xylyl group permits the ligand to convert to an endodentate conformation, permitting facial coordination at a metal atom. The ligand 5-oxa-2,8-dithia (9) -o-cyclophane, ODT (9) OC, may also coordinate to metal centres in a facial manner. Chapters 1 and 2 serve as a study of the coordinative ability of TT (9) OC and ODT (9) OC at Ag(I). The 2:1 reaction of TT (9) OC with silver salts results in (Ag(TT (9) OC)$\sb2\rbrack\sp+,$ 1-4. X-ray diffraction studies indicate that coordination geometries depend on the counterions involved; the ligand TT (9) OC binds to silver through one, two, or all three sulphur donors. In a 2:1 reaction of ODT (9) OC with Ag(I), it was found that only the two sulphur donors coordinate to the metal in complex, (Ag(ODT) (9) OC)$\sb2\rbrack\sp+.$ In 1:1 reactions of TT (9) OC with Ag(I), tetranuclear aggregates (Ag(TT (9) OC)) $\sb4\sp{4+},$ and are formed. In comparison, the ligand TT (9) MC cannot convert to an endodentate form, and complex, (Ag(TT (9) MC) $\rm\sb{x}\sp{x+},$ is a polymeric complex. The complexes (M(COD)(TT (9) OCO) $\sp+,$ (M = Rh, Ir), 0 and 1, are coordinatively saturated. (Rh(COD)(TT (9) OC) $\sp+,$ reacts with CO to form an unusual dimeric complex ((TT (9) OC)Rh($\mu$-CO)$\sb3$Rh(TT (9) OC)) $\sp{2+},$ 5, but the Ir(I) analog does not undergo the same type of substitution reaction, and (Ir (CO)$\sb2$(TT) (9) OC)) $\sp+,$ 8, is synthesized from the reaction of (IrCl(COE)$\sb2\rbrack\sb2$ with AgBF$\sb4$ and TT (9) OC under CO. The products of the reactions of 0 and 1 with NOBF$\sb4$ decompose quickly in solution due to perturbation of TT (9) OC. The complexes (M(COD)(ODT) (9) OC)) $\sp+,$ (M = Rh, Ir), 2 and 3, are square planar coordinatively unsaturated complexes, both of which undergo substitution reactions with CO to form (M(CO)$\sb3$(ODT (9) OC)) $\sp+.$ Reactions with NOBF$\sb4$ yield products that are thermodynamically more stable than those of 0 and 1. The structure of complex 5, RuCl$\sb2$(PPh$\sb3)$(ODT (9) OC) shows that the crown thioether ligand is bound to the metal through all three donor atoms, and as well, the aromatic portion of the ligand is bent away from PPh$\sb3,$ two conformations not previously observed for any of the thiacyclophane complexes studied previously by this group. Source: Dissertation Abstracts International, Volume: 56-11, Section: B, page: 6107. Adviser: Stephen J. Loeb. Thesis (Ph.D.)--University of Windsor (Canada), 1994.

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