The strong cooperativity of dioxygen binding by dicobalt (II) diporphyrin compounds in nonaqueous solution at room temperature |
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Authors: | Zhou Xiaohai Deng Lizhi Wu Xuye Zhang Shaohui Liu Shengquan Huang Suqiu Qu Songsheng |
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Institution: | (1) Department of Chemistry, Wuhan University, 430072 Wuhan, China |
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Abstract: | Thermodynamic data were determined for the reversible binding of O2 to two compounds of dicobalt(II) di(meso-tetra-phenyl)porphyrin derivatives with different lengths of diamidoaliphatic bridge
(abbreviated to Co2PP8 and Co2PP4) in N,N-dimethylformamide at room temperature. The partial pressure of dioxygen necessary for half-oxygenation (P
1/2) and hill coefficient (n) at 298 K were determined as follows:P
1/2=54.2 kPa,n=2.0 for Co2PP8 andP
1/2=6.8 kPa,n=1.8 for Co2PP4, respectively. The rate equations of reversible oxygen binding by Co2PP8 were determined and the reaction path was proposed. The results of ther-modynamic and kinetic studies indicate that there
exists strong cooperative effect during oxygenation of the compounds. The ESR observation reveals that the dioxygen complexes
formed in the solutions are of superoxo (Co-O
2
−
) type.
Supported by the Research Foundation of the State Education Commission of China
Zhou Xiaohai: born in 1962, Ph.D. Associate professor |
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Keywords: | dicobalt (II) diporphyrin model compounds of hemoglobin cooperative effect reversible dioxygen binding thermodynamics kinetics |
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