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Theoretical calculations on the conformation of cyclopentadienyl coordination in Ru nitrosyl and thionitrosyl complexes

Conference ·
OSTI ID:126860
; ;  [1]
  1. Pacific Northwest Lab., Richland, WA (United States); and others
X-ray structural characterization of a series of CpRu(NE)LL` complexes (Cp = cyclopentadieny), C{sub 5}R{sub 5}; L, L` = ligand; E = O, S) reveals systematic trends in the coordination conformation of the cyclopentadienyl ligand. The thionitrosyl complex (C{sub 5}(CH{sub 3}){sub 5})Ru(NS)Cl{sub 2} exhibits a slipped (eta-3,eta-2 Cp ring, with the central C(skeletal)-CH{sub 3} bond of the more tightly bound eta-3 portion eclipsing the Ru-N-S vector. With NO derivatives, ring {open_quotes}slippage{close_quotes} is not significant, but ring orientation is variable depending upon the L and L` ligand set. NMR spectroscopy measurements show that the barriers to changes in ring conformation become very low in solution. For catalytic purposes, it is of interest to fix the Cp geometry with respect to rotation. Ab initio SCF and DFT calculations have been performed, using the NWChem suite of computer codes, developed at Pacific Northwest Laboratory, to explore three questions: By what mechanism does the choice of ligand affect the Cp orientation? What is the barrier to rotation of the Cp? By what mechanism does salvation affect the barriers to Cp rotation?
OSTI ID:
126860
Report Number(s):
CONF-950402--
Country of Publication:
United States
Language:
English