Title
The preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten
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
Copyright Date
1981
Language
en
Proquest ID
AAI8123129
File Format
application/pdf
File Size
157 pages
Recommended Citation
Ryan, Timothy Richard, "The preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten " (1981). Retrospective Theses and Dissertations. 6884.
https://lib.dr.iastate.edu/rtd/6884