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Preparation, properties, and crystal structure of a novel series of macrocyclic organocobalt complexes

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00273a015· OSTI ID:5845281
The organocobalt complexes ((H/sub 2/O)((14)aneN/sub 4/)CoR)(ClO/sub 4/)/sub 2/ (R = primary alkyl, substituted primary alkyl, and benzyl; (14)aneN/sub 4/ = 1,4,8,11-tetraazacyclotetradecane) were prepared photochemically from the corresponding alkylcobaloximes and the cobalt(II) macrocycle. The complexes were characterized by elemental analysis, /sup 1/H NMR spectroscopy, a crystal structure determination for R = ethyl, and uv-visible spectroscopy. The ethyl complex, ((H/sub 2/O)((14)aneN/sub 4/)CoC/sub 2/H/sub 5/)(ClO/sub 4/)/sub 2/ /times/ H/sub 2/O, crystallizes in the monoclinic crystal system, space group P2/sub 1//n, with four molecules in a unit cell of dimensions a = 8.901 (11) /angstrom/, b = 12.254 (21) /angstrom/, c = 19.637 (15) /angstrom/ and /beta/ = 91.76 (22)/degree/. The data refined to a final value of the weighted R factor of 0.083 based on 1242 independent observations. The complex is hexacoordinated, with the ethyl group and a coordinated molecule of water as axial ligands. All of the complexes are photosensitive and readily decompose to cobalt(II) and carbon-centered radicals when irradiated with visible light. Air-stable acidic aqueous solutions of the alkyl complexes show no sign of decomposition in hours when kept in the dark. The hydroxymethyl complex, prepared by a modified Fenton reaction, is air-sensitive, and the benzyl complex undergoes rapid homolysis of the cobalt-carbon bond. 31 references, 1 figure, 5 tables.
Research Organization:
Iowa State Univ., Ames (USA)
DOE Contract Number:
W-7405-ENG-82
OSTI ID:
5845281
Journal Information:
Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 26:26; ISSN INOCA
Country of Publication:
United States
Language:
English