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Rhenium(I) Tricarbonyl Complexes of 5,10,15,20-Tetraphenyl-21-thia and 21-Oxaporphyrins

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Title Rhenium(I) Tricarbonyl Complexes of 5,10,15,20-Tetraphenyl-21-thia and 21-Oxaporphyrins
 
Creator GHOSH, A
RAVIKANTH, M
 
Subject N-FUSED TETRAPHENYLPORPHYRIN
STRUCTURAL-CHARACTERIZATION
UNUSUAL METALLOPORPHYRINS
21-THIAPORPHYRIN COMPLEX
ELECTROCHEMICAL PROPERTIES
COPPER(II) COMPLEXES
NICKEL-COMPLEXES
PORPHYRINS
 
Description The hexa-coordinated rhenium(I) tricarbonyl complexes of 5,10,15,20-tetraphenyl-21-thiaporphyrin 1 and S,10,15,20-tetraphenyl-21-oxaporphyrin 2 have been synthesized by thermal reaction of corresponding free base porphyrin with Re-2(CO)(10). The compounds 1 and 2 are characterized by HR-MS mass, H-1, and C-13 NMR, FTIR, UV-vis, and electrochemical techniques and the structures are determined by X-ray single crystal analysis. The X-ray analysis revealed different coordination behavior of Re(CO)(3) with 21-thiaporphyrin and 21-oxaporphyrin. Interestingly, the Re(CO)(3) coordinates to two of the three inner nitrogens and one sulfur instead of three inner nitrogens as generally expected to produce unique compound 1 whereas it coordinates to three inner nitrogens but not with loran oxygen to form compound 2. The 21-thiaporphyrin ring is more distorted in compound 1 compared to 21-oxaporphyrin ring in compound 2 on complexation with Re(CO)(3). The presence of three carbonyl groups in compounds 1 and 2 are verified by C-13 NMR and IR spectroscopy. The absorption spectra of compounds 1 and 2 showed ill-defined Q-bands along with broad Soret band and the extinction coefficients are much lower than their corresponding free base porphyrins. The compounds 1 and 2 showed two reversible porphyrin ring based reductions supporting their electron deficient nature. The compound 1 is very stable under protonation conditions, and the protonation occurs at the uncoordinated pyrrole ring whereas the compound 2 undergoes decomplexation under same conditions. Furthermore, compound 1 showed the fluxional behavior in coordination mode of binding in solution.
 
Publisher AMER CHEMICAL SOC
 
Date 2014-10-16T13:38:35Z
2014-10-16T13:38:35Z
2012
 
Type Article
 
Identifier INORGANIC CHEMISTRY, 51(12)6700-6709
http://dx.doi.org/10.1021/ic300344g
http://dspace.library.iitb.ac.in/jspui/handle/100/15686
 
Language en