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Title: Preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten

Abstract

The cyclo-addition of two Mo/sub 2/Cl/sub 4/(P(C/sub 6/H/sub 5/)/sub 3/)/sub 2/(CH/sub 3/OH)/sub 2/ molecules has produced a new type of tetrameric molybdenum cluster, Mo/sub 4/Cl/sub 8/L/sub 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/sub 4/X/sub 8/L/sub 4/ clusters where X = Cl, Br, I and L = PR/sub 3/, Po/sub 3/, RCN, CH/sub 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/sub 4/Cl/sub 8/(PR/sub 3/)/sub 4/, R = C/sub 2/H/sub 5/, n-C/sub 4/H/sub 9/. The preparation of the analogous W/sub 4/Cl/sub 8/(PR/sub 3/)/sub 4/ cluster from WCl/sub 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/sub 2/(mhp)/sub 4/ was unsuccessful (mhp = anion of 2-methyl-6-hydroxypyridine). Instead, the new tungsten dimer, W/sub 2/Cl/sub 2/(mhp)/sub 3/, was isolated which possessed a metal-metal bond order of 3.5.more » The x-ray crystal structure of the dimer revealed that the chlorine atoms were situated cis, one bound to each tungsten. Cyclic voltammetry showed that the compound could be reversibly reduced, presumably to a W/sub 2//sup 4 +/ dimer containing a quadruple metal-metal bond.« less

Authors:
Publication Date:
Research Org.:
Ames Lab., IA (USA)
OSTI Identifier:
5530833
Report Number(s):
IS-T-952
ON: DE82005456
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MOLYBDENUM COMPLEXES; CRYSTAL STRUCTURE; TUNGSTEN COMPLEXES; BROMIDES; CHLORIDES; DIMERS; IODIDES; METHANOL; NITRILES; PHOSPHINES; PYRIDINES; ALCOHOLS; AZINES; BROMINE COMPOUNDS; CHLORINE COMPOUNDS; COMPLEXES; HALIDES; HALOGEN COMPOUNDS; HETEROCYCLIC COMPOUNDS; HYDROXY COMPOUNDS; IODINE COMPOUNDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHOSPHORUS COMPOUNDS; TRANSITION ELEMENT COMPLEXES; 400201* - Chemical & Physicochemical Properties

Citation Formats

Ryan, T. R. Preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten. United States: N. p., 1981. Web. doi:10.2172/5530833.
Ryan, T. R. Preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten. United States. doi:10.2172/5530833.
Ryan, T. R. Thu . "Preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten". United States. doi:10.2172/5530833. https://www.osti.gov/servlets/purl/5530833.
@article{osti_5530833,
title = {Preparation and characterization of dimeric and tetrameric clusters of molybdenum and tungsten},
author = {Ryan, T. R.},
abstractNote = {The cyclo-addition of two Mo/sub 2/Cl/sub 4/(P(C/sub 6/H/sub 5/)/sub 3/)/sub 2/(CH/sub 3/OH)/sub 2/ molecules has produced a new type of tetrameric molybdenum cluster, Mo/sub 4/Cl/sub 8/L/sub 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/sub 4/X/sub 8/L/sub 4/ clusters where X = Cl, Br, I and L = PR/sub 3/, Po/sub 3/, RCN, CH/sub 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/sub 4/Cl/sub 8/(PR/sub 3/)/sub 4/, R = C/sub 2/H/sub 5/, n-C/sub 4/H/sub 9/. The preparation of the analogous W/sub 4/Cl/sub 8/(PR/sub 3/)/sub 4/ cluster from WCl/sub 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/sub 2/(mhp)/sub 4/ was unsuccessful (mhp = anion of 2-methyl-6-hydroxypyridine). Instead, the new tungsten dimer, W/sub 2/Cl/sub 2/(mhp)/sub 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 were situated cis, one bound to each tungsten. Cyclic voltammetry showed that the compound could be reversibly reduced, presumably to a W/sub 2//sup 4 +/ dimer containing a quadruple metal-metal bond.},
doi = {10.2172/5530833},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1981},
month = {10}
}