title: Influence of nonplanarity and extended conjugation on porphyrin basicity.
abstract: Thermodynamic basicities of several new nonplanar water soluble tetraaryltetracyclohexano- (Ar(4)TCHP) and tetraaryltetrabenzoporphyrins (Ar(4)TBP) have been measured and correlated with their structural parameters. While the degrees of nonplanarity in these porphyrins are similar, Ar(4)TCHPs exhibit significantly higher basicities than Ar(4)TBPs and than planar tetraarylporphyrins. Low basicities of distorted Ar(4)TBPs are believed to be due to extended pi-conjugation, which causes delocalization of the core electron density in these porphyrins and reduces negative charges at the protonation site.
authors.affiliation: Department of Chemistry, Moscow State University, Russia.
authors.forename: Olga S
authors.initials: OS
authors.lastname: Finikova
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Cheprakov
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Carroll
authors.forename: Sergio
authors.initials: S
authors.lastname: Dalosto
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Vinogradov
mesh_terms: D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D011166:Porphyrins