Degree Type

Dissertation

Date of Award

1981

Degree Name

Doctor of Philosophy

Department

Chemistry

Abstract

The cyclo-addition of two Mo(,2)Cl(,4)P(C(,6)H(,5))(,3)(,2)(CH(,3)OH)(,2) molecules has produced a new type of tetrameric molybdenum cluster, Mo(,4)Cl(,8)L(,4). Structural characterization of this dimer revealed weak molybdenum-methanol bonding which was consistent with the observed reactivity of the compound. New synthetic methods were devised for the preparation of Mo(,4)X(,8)L(,4) clusters where X = Cl, Br, I and L = PR(,3), P(SLASHCIRC)(,3), RCN, CH(,3)OH. A scheme for the metal-metal bonding in these clusters was presented which was in agreement with the known structural features of Mo(,4)Cl(,8)(PR(,3))(,4), R = C(,2)H(,5), n-C(,4)H(,9);The preparation of the analogous W(,4)Cl(,8)(PR(,3))(,4) cluster fromWCl(,4) was accomplished by application of techniques used in the molybdenum syntheses. The single crystal x-ray structure revealed slight differences from the molybdenum analog which were rationalized in terms of the known behavior in dimeric tungsten and molybdenum species;The attempted preparation of a tetrameric tungsten cluster from W(,2)(mhp)(,4) was unsuccessful (mhp = anion of 2-methyl-6-hydroxypyridine). Instead, the new tungsten dimer, W(,2)Cl(,2)(mhp)(,3), was isolated which possessed a metal-metal bond order of 3.5. The x-ray crystal structure of the dimer revealed that the chlorine atoms was situated cis, one bound to each tungsten. Cyclic voltammetry showed that the compound could be reversibly reduced, presumably to a W(,2)('4+) dimer containing a quadruple metal-metal bond;('1)DOE Report IS-T-952. This work was performed under contractW-7405-eng-82 with the Department of Energy.

DOI

https://doi.org/10.31274/rtd-180813-12569

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Timothy Richard Ryan

Language

en

Proquest ID

AAI8123129

File Format

application/pdf

File Size

157 pages

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