Cation-induced crown porphyrin dimers of oxovanadium(IV)
Data(s) |
01/10/1982
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Resumo |
Oxovanadium(1V) porphyrins appended with crown ether (benzo-15-crown-5) at the 5 (mono), the 5 and 10115 (cis/trans bis), the 5, 10, and 15 (tris), and the 5, 10, 15, and 20 (tetrakis) positions have been synthesized. The cation complexation behavior of these cavity-bearing porphyrins has been studied by using optical aborption and ESR spectral methods. The cations K+, Cs+, NH4+, and Ba2+, which require two crown ether cavities for complexation, induce dimerization of the porphyrins. The cation-induced dimerization constants for a representative tetrasubstituted porphyrin vary as K+ > Ba2+ > Cs+ - NH4+, and the relative stabilities of the dimers are dependent on the type of the substitution, tetrakis > tris > cis bis. ESR spectra recorded at a sample temperature of 77 K have low-field components attributed to Ah& = f 2 transitions, providing further evidence for the existence of dimers in solutions. The eclipsed sandwich dimers have V-V distances in the range 4.70 A. The relative distributions of oxovanadium crown porphyrins in terms of monomeric and dimeric forms rest on the geometric dispositions of the crown ether appendages. |
Formato |
application/pdf |
Identificador |
http://eprints.iisc.ernet.in/20892/1/fulltext.pdf Thanabal, V and Krishan, V (1982) Cation-induced crown porphyrin dimers of oxovanadium(IV). In: Inorganic Chemistry, 21 (10). pp. 3606-3613. |
Publicador |
American Chemical Society |
Relação |
http://pubs.acs.org/doi/abs/10.1021/ic00140a006?prevSearch=[title%3A+CATION-INDUCED+CROWN+PORPHYRIN+DIMERS+OF+OXOVANADIUM(IV)]&searchHistoryKey= http://eprints.iisc.ernet.in/20892/ |
Palavras-Chave | #Inorganic & Physical Chemistry |
Tipo |
Journal Article PeerReviewed |