Date of Award

1988

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

Joel Selbin

Abstract

Four palladium-silver and seven palladium-rhodium heterodinuclear complexes have been prepared by treatment of t-(NC)$\sb2$Pd(dppm)$\sb2$ with suitable silver salts and with (RhCl(cod)) $\sb2$ and suitable silver salts and with (RhCl(cod)) $\sb2$ and suitable tertiary phosphines, respectively. The molecular structure of t-(NC)$\sb2$Pd(dppm)$\sb2$Ag(ONO) has been determined by single-crystal X-ray diffraction. The crystals are monoclinic, space group P2$\sb1$/c, a = 14.745(7) A, b = 19.208(7) A, c = 17.486(6) A, $\beta$ = 94.99(2)$\sp\circ$, and Z = 4. The final R factor was 0.032 for 8673 unique reflections. The phosphorus-31 nmr spectra of the four Pd-Ag complexes have been analyzed by computer program simulation to find Ag-P coupling constants for the four pairs of isotopic isomers of the silver-107 and silver-109 complexes. A comparison of the $\sp{31}$P-$\{\sp1$H$\}$ nmr spectra of complexes t-(NC)$\sb2$Pd(dppm)$\sb2$Ag(ONO) and t-(NC)$\sb2$Pd(dppm)$\sb2$Ag-(ONO$\sb2$) shows that the additional oxygen atom in the nitrate complex decreases the electron density around the phosphorus atoms bonded to the silver center, but increases the s character of the electron density between these phosphorus atoms and the silver atom in the same molecule. A comparison of the $\sp{31}$P-$\{\sp1$H$\}$ nmr spectra of complexes t-(NC)$\sb2$Pd(dppm)$\sb2$Ag(OOCH) and t-(NC)$\sb2$Pd(dppm)$\sb2$Ag(OOCMe) shows that the substitution of the hydrogen in the formate complex by the methyl group in the acetate complex increases the electron density around the phosphorus atoms bonded to the silver center, but decreases the s character of the electron density between these phosphorus atoms and the silver atom. The three complexes: t-(NC)$\sb2$Pd(dppm)$\sb2$RhClZ, in which Z = P(OEt)$\sb3$, PPh$\sb3$, and P(Tol-p)$\sb3$, have been prepared by two methods which use the same starting materials: (RhCl(cod)) $\sb2$, t-(NC)$\sb2$Pd(dppm)$\sb2$, and the appropriate phosphorus ligand. The two methods produce the same product via different intermediate(s) involving different reaction sequences. Complexes t-(NC)$\sb2$Pd(dppm)$\sb2$RhClZ, in which Z = PPh$\sb2$(OMe), P(OPh)$\sb3$, PPh$\sb2$(Tol-p), and -picoline, have been prepared by only one method. All the Pd-Ag and Pd-Rh heterodinuclear complexes give $\sp{31}$P-$\{\sp1$H$\}$ nmr spectra with some common aspects and some differences. The new heterodinuclear complexes are expected to possess unique catalytic activity based upon the uniqueness of the heterodimetal centers.

Pages

198

DOI

10.31390/gradschool_disstheses.4517

Download

Share

COinS