Position isomer separation of non-peripheral substituted zinc dibenzo-di(3,4-pyrido)porphyrazines

Abstract

ABSTRACT:The cyclotetramerisation products from the 1, 8-diazabicyclo[5,4,0]undec-7-ene catalysed reaction of a 1:1 mol mixture of 3,6-didecylphthalonitrile and 3,4-dicynopyridine in the presence of zinc chloride have been isolated by chromatography. The fractions comprise zinc octadecylphthalocyanine and compounds in which one, two, three and four pyridinoid rings replace the didecylbenzenoid moiety. The zinc bis(1,4-didecylbenzo)bis(3,4-pyrido)porphyrazine fraction was separated further into four sub-fractions and the components have been characterised by 400 MHz proton nuclear magnetic resonance spectroscopy, visible region spectroscopy, fluorescence spectroscopy and by cyclic voltammetry.

Synthesis of substituted phthalocyanines

“…Most of this type of phthalocyanine compounds have originated from Cook's group, 53 which developed a very elegant way for preparation of the key precursors, e.g. 3,6-dialkylphthalonitriles, using the Diels-Alder reaction (Scheme 7).…”

Synthesis of alkylthio substituted pyridoporphyrazines and their photophysicochemical properties

“…These results mean that the 5 and 6 have a proposed structure in accordance with the stoichiometric ratio. Of course, each compound is a mixture of five regioisomers which possess two pyridine rings and two non-peripheral substituted benzenoid rings at different locations in the molecules as previously reported [11]. In Scheme 1, typical molecular structures of 5 and 6 are described.…”

“…Undoubtedly, the obtained phthalocyanines and their related compounds were composed of only one constituent, while on the other hand, it is thought that target compounds zinc bis(didecylthiobenzo)-bis(pyrido)porphyrazines 5 and 6, synthesized from mixed raw materials by cross cyclotetramerization, were prepared as a mixture of products which have different number of pyridine rings in the molecule. The authors previously reported that alkylbenzopyridoporphyrazine synthesized from mixed raw materials has desired molecular structure for its main constituents [11].…”

“…The strongest absorption maxima of phthalocyanines and their related compounds in visible region called the Q band can be moved by bathochromic effect to introduce an electron-donating substituent at a non-peripheral (1,4,8,11,15,18,22,25) position. For PDT photosensitizers, the absorption maxima of phthalo cyanines and their related compounds are best when moved to the nearinfrared region [2,9].…”

“…The phthalocyanine related compounds containing a pyridine ring in place of one or more of benzenoid rings are interesting compounds because quaternation of pyridine nitrogen is expected to confer solubility in an aqueous media [2,11]. Furthermore, the authors have reported that the length of triplet lifetime alkylbenzopyridoporphyrazines increased with the number of pyridine rings in the molecule [2].…”