Oktakatyonik ve supramoleküler porfirazinler

Özet

Bu çalışmada oktakatyonik ve nona nükleer supramoleküler porfirazin kompleksleri sentezlenmiş ve spektral yöntemlerle karakterize edilmiştir. Hedeflenen oktakatyonik ve supramoleküler yapıların hazırlanması için daha önce çalışma grubumuz tarafından sentezlenmiş olan oktakis (2-hidroksietiltiyo) porfirazinatomagnezyum (MgOHPz) molekülü yeniden sentezlenmiştir. Supramoleküler yapının ilk basamağı olan MgOHPz molekülünün DCCI katalizörlüğünde piridin karboksilik asit ile kondenzasyonundan sonra oluşacak periferal konumda 8 tane piridin donör grubu içeren yeni bir porfirazin yapısı sentezlenmiş, ikinci adımda periferal piridinler kuaternize edilip okta katyonik yapıya ulaşılmıştır. Son aşama olarak da periferal piridinler üzerinden paramanyetik VO(acac)2 metal merkezleri ile koordinasyon bağları oluşturmak suretiyle nonanükleer supramoleküler sistemler elde edilmiştir. Ayrıca sentezlenen paramanyetik supramolekülün EPR yöntemi ile yapısı aydınlatılmıştır.

Abstract

In this study, octacationic and nonanuclear supramolecular porphyrazines were synthesized and characterized by the common spectral methods. For the synthesis of target octacationic and supramolecular structures, first the octakis(2-hydroxyethylthio)porhyrazinatomagnesium (MgOHPz) which was required for the designing of the core of the supramolecule, was synthesized as given in the literature. The second step of the supramolecular structure was the addition of pyridyl donors on the periferal positions of the porphyrazine unit. For this purpose, MgOHPz was reacted with pyridine-4-carboxylic acid to give the ester units on the periferies of porphyrazine. Octakis(4-pyridoxyethylthio)porphyrazinato magnesium,(MgPyPz) was prepared by the complete esterification of all the OH-groups in MgOHPz with with pyridine-4-carboxylic acid (isonicotinic acid) in pyridine by the presence of dicyclohexylcarbodiimide and 4-toluenesulphonic acid as catalysts in seven days at ambient temperature. The blue-green color octakis(4-pyridoxyethylthio)porphyrazinatomagnesium, MgPyPz, was isolated with good yield. The octacationic molecule was obtained after the quaternization of the MgPyPz with iodomethane in the dark. The ready solubility of the product in water confirms the proposed structure. The nonanuclear supramolecule was prepared by the coordination reaction of the vanadylacetylacetonate, VO(acac)2 with MgPyPz and characterized by EPR technique together with the usual spectral data.