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Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.50A [2011] >
IJC-A Vol.50A(09-10) [September-October 2011] >
| Title: | Synthesis and reactivity of cobalt complexes derived from tris(2-pyridylthio)methane ligand: Structural characterization of cobalt(III) complexes containing cobalt–carbon bond |
| Authors: | Halder, Partha
Paine, Tapan Kanti |
| Keywords: | Organometallic compounds
Organocobalt complexes
Metal–carbon bond
Solid state structure
Cobalt
Oxidation |
| Issue Date: | Sep-2011 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | The synthesis, characterization and reactivity of a cobalt(II) complex,
[(HL1)CoII(PyS)](ClO4) (1) (where
HL1 = tris(2-pyridylthio)methane and PyS = monoanionic
pyridine-2-thiolate) are discussed. Complex (1) reacts with molecular oxygen to yield a mononuclear low-spin
cobalt(III) complex, [(L1)CoIII(PyS)](ClO4) (2). On the other hand, treatment of (1) with a protic acid (pyridinium
perchlorate) followed by a base (triethylamine) and dioxygen
forms an isomeric cobalt(III) complex, [(L2)CoIII(PyS)](ClO4)
(3) (L2 =
1-[bis(2-pyridylthio)methyl]pyridine-2-thione). Ligand HL1 (in 1)
rearranges to L2 (in 3)
during the reaction as a result of C–S bond cleavage and subsequent C–N bond
formation. X-ray crystal structures of both (2) and (3) reveal a
distorted octahedral coordination geometry at cobalt(III) center with a strong
cobalt–carbon bonding interaction. A four-coordinate distorted tetrahedral
cobalt(II) complex, [CoII(PySH)4](ClO4)2
(4) is formed via C–S bond cleavage
of HL1 in the reaction of (1)
with an excess amount of pyridinium perchlorate. The electronic structure of (2) as established by DFT calculation
suggests a delocalized LUMO with significant contribution from the metal ion.
The organocobalt(III) complex converts to an air-stable organocobalt(II)
complex (2red) upon
one-electron reduction. |
| Page(s): | 1394-1402 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-0975(Online); 0376-4710(Print) |
| Source: | IJC-A Vol.50A(09-10) [September-October 2011]
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