Dynamic structural change of a twisted hexaporphyrin complex by highly specific molecular recognition

Hiroaki Kitagishi; Akiharu Satake; Yoshiaki Kobuke

doi:10.1021/ic049645g

Dynamic structural change of a twisted hexaporphyrin complex by highly specific molecular recognition

Inorg Chem. 2004 May 31;43(11):3394-405. doi: 10.1021/ic049645g.

Authors

Hiroaki Kitagishi¹, Akiharu Satake, Yoshiaki Kobuke

Affiliation

¹ Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.

PMID: 15154801
DOI: 10.1021/ic049645g

Abstract

The highly specific molecular recognition of a twisted hexaporphyrin complex, tris[5,5'-bis[5,10,15-tris[methoxy(ethoxy)(2)carbonylethyl]porphyrinatozinc(II)]-2,2'-bipyridine]ruthenium(II) chloride (2), is described. Complex 2 has two trisporphyrin binding sites and can bind two triamines, tris(2-aminoethyl)amine (3) (K(1) = 3.0 x 10(8) M(-1), K(2) = 3.0 x 10(7) M(-1)), 1,1,1-tris(aminomethyl)ethane (4) (K(1) = 2.0 x 10(7) M(-1), K(2) = 1.4 x 10(6) M(-1)), tris(3-aminopropyl)amine (5) (K(1) = 3.5 x 10(6) M(-1), K(2) = 6.0 x 10(6) M(-1)), and 1,3,5-tris(aminomethyl)benzene (6) (K(1) = 2.9 x 10(6) M(-1), K(2) = 1.2 x 10(6) M(-1)), strongly with its torsional motion. The 1:2 complex between 2 and the best fit triamine 3 showed the nature of the specific rigid structure in the UV-vis, fluorescence, and (1)H NMR spectra and isothermal titration calorimetry (ITC) measurements.