Synthesis of new porphyrazines and investigation of their properties

Abstract

In this study five dinitrile derivatives were synthesized in order to prepare novel porphyrazines. Bis(p-nitro benzylthio) maleonitrile, 6-oxo-6,7-dihydro-5H-[1,4]dithiepine-2,3-dicarbonitrile and bis(2-cyano-ethylthio) maleonitrile did not yield porphyrazines under different conditions. However, magnesium porphyrazines were obtained by the cyclotetramerization of 6,7,8,8a-tetrahydro-4aH-[1,4]dithiino-[2,3-b]pyran-2,3-dicarbonitrile (Ll) and 5-ethoxy-5,6-dihydro-[1,4]dithiino-2,3-dicarbonitrile (L2) ligands( which include cis-cyano groups) in the presence of magnesium butanolate. These porphyrazines were treated with trifluoroacetic acid to demetallize. Due to low solubility of metal-free porphyrazine derivatives, metallization process was unsuccessful with copper and zinc acetates. So acetylacetonate complexes of copper and zinc were prepared. Since these complexes were dissolved in organic solvents, they were refluxed with metal-free porphyrazines in THF to yield zinc and copper derivatives. However, elemental analysis results indicated that additional eight Cu(acac)2 units are present in the case of both CuPzl and CuPz2. All novel compounds were characterized by using $^1H NMR$, Mass, IR and UV-VIS spectrophotometric methods as well as elementel analysis results. The electrochemical behaviours of all porphyrazines' were investigated by Cylic Voltametry. While electrochemical behaviour of magnesium,metal- free and zinc derivatives were quite similar, those of copper derivatives showed additional features resulting from coordinated copper acetylacetonates.

Özet

Bu çalışmada, porfirazin sentezinde kullanmak amacıyla beş farklı dinitril türevi elde edilmiştir. Bis(p-nitrobenzil)maleonitril, 6-okso-6,7-dihidro-5H-[1,4]ditiepin-2,3-dikarbonitril ve Bis(2-siyano-etiltiyo) maleonitril optimum şartlarda dahi porfirazin vermemiştir. Ancak 6,7,8,8a-tetrahidro-4aH-[1,4]ditiino-[2,3-b] piran-2,3-dikarbonitril (L1) ve 5-etoksi-5,6-dihidro-[l,4]ditüno-2,3-dikarbonitril (L2) ligandlarının magnezyum butonol içerisinde siklotetramerize olmasıyla hedeflenen magnezyum porfirazinler elde edilmiştir. Sentezlenen bu porfirazinler trifloroasetik asit ile reaksiyona sokularak metalsiz hale dönüştürülmüşlerdir. Çinko ve bakırın asetilasetonat kompleksleri, istenen metalli türevleri vermiştir. Tüm yeni bileşikler $^1H NMR$, Kütle, IR ve UV-Görünür Bölge spektroskopik yöntemleriyle ve elementel analiz sonuçlarıyla karakterize edilirken, porfirazinlerin elektrokimyasal davranışları CV kullanılarak incelenmiştir.