This work is concerned with the preparation and examination of guanidinate complexes. One method of synthesis of such ligands, as presented in Chapter 2, is the insertion of carbodiimide into a metal-amido group. The direct reactions of $\rm M(NMe\sb2)\sb5$ with either dicyclohexylcarbodiimide (CyN=C=NCy) or diisopropylcarbodiimide $\rm(\sp{i}PrN{=}C{=}N\sp{i}Pr)$ proceeded smoothly at room temperature under nitrogen to yield $\rm\lbrack RNC(NMe\sb2)NR\rbrack M(NMe\sb2)\sb4$ (M = Ta, Nb; R = Cy, $\rm\sp{i}Pr).$ The spectroscopic characterization of these materials is consistent with a symmetrical chelating bidentate guanidinate anion bonded to a pseudo-octahedral metal center. In chapter 3, we prepared $\rm N,N\sp\prime,N\sp{\prime\prime}$-tricyclohexylguanidine and triisopropylguanidine. With this guanidine ligand, we focus on the elimination of amido ligands from homoleptic Ta(V) and Nb(V) dimethylamido complexes. The complex $\rm TaCl(NMe\sb2)\sb3\{\lbrack CH\sb3)\sb2CHN\rbrack\sb2CN(H)CH(CH\sb3)\sb2\}$ was also isolated and crystallographically characterized. In Chapter 4, the direct reaction of Ta and Nb alkyl complexes $\rm M(Me)\sb{x}Cl\sb{y}$ (M = Ta, x = 3, y = 2; M = Nb, x = 2, y = 3) with $\rm N,N\sp\prime,N\sp{\prime\prime}$-tricyclohexylguanidine and $\rm N,N\sp\prime,N\sp{\prime\prime}$-triisopropylguanidine was investigated. The preliminary results of efforts to get a second alkyl elimination are also reported. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/4436 |
| Date | January 1998 |
| Creators | Tin, Ma Khin Than. |
| Contributors | Richeson, Darrin, |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 101 p. |
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