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Poly(tertiary phosphines and arsines). 20. Some reactions of (methylamino)bis(dimethoxyphosphine) and crystal structure of (. mu. -carbonyl)(. mu. -(methylamino)bis(dimethoxyphosphine))bis(tricarbonyliron), CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/Fe/sub 2/(CO)/sub 7/

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00140a037· OSTI ID:6234734

Reactions of the complexes (norbornadiene)M(CO)/sub 4/ (M = Cr and Mo) with CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/ give the corresponding CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/M(CO)/sub 4/ chelate complexes. Reactions of iron carbonyls with CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/ under appropriate conditions give the bridged binuclear complexes )CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/)/sub n/Fe/sub 2/(CO)/sub 9-2n/ (n = 1 and 2). The infrared v(CO) frequencies of metal carbonyl complexes of CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/ are consistently lower than those of analogous CH/sub 3/N(PF/sub 2/)/sub 2/ complexes, in accord with the lower ..pi..-acceptor strength of CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/ relative to that of CH/sub 3/N(PF/sub 2/)/sub 2/. Single-crystal X-ray diffraction analysis shows the complex CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/Fe/sub 2/(CO)/sub 7/ (3) to have an Fe-Fe bond 2.6606 (5) angstrom long that is bridged by one CO group and by the bidentate ligand CH/sub 3/N(P(OCH/sub 3/)/sub 2/)/sub 2/.The CO group, the N atom, and the midpoint of the Fe-Fe bond are located on a crystallographic mirror plane. The Fe-P bond length is 2.1919 (5) angstrom, and the P-N bond length is 1.665 (1) angstrom. The Fe/sub 2/P/sub 2/N ring conformation is almost exactly plane, unusual for either M/sub 2/P/sub 2/N or M/sub 2/P/sub 2/C rings. The Fe/sub 2/P/sub 2/N best plane is at approx. 90/sup 0/ to the best plane through the two Fe atoms and five of the carbonyl carbon atoms, including the bridging carbon. Except for the nearly plane Fe/sub 2/P/sub 2/N ring, the structure of the moiety Fe/sub 2/P/sub 2/N(CO)/sub 7/ is remarkably close, even in some rather fine details, to that of the moiety Fe/sub 2/P/sub 2/C(CO)/sub 7/ in CH/sub 2/(P(C/sub 6/H/sub 5/)/sub 2/)/sub 2/Fe/sub 2/(CO)/sub 7/ as described by Cotton and Troup.

DOE Contract Number:
W-7405-ENG-26
OSTI ID:
6234734
Journal Information:
Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 21:10; ISSN INOCA
Country of Publication:
United States
Language:
English