Synthesis and characterization of new metallo and metal-free porphyrazines containing dioxadithia (O2S2) and tetrathia (S4) macrocyclic moieties

The synthesis of new magnesium porphyrazines, peripherally substituted with 14-membered dioxa-dithia (O2S2) and tetrathia (S4) macrocycles has been accomplished by cyclotetramerization of (6Z)-1,3,4,9,10,12-hexahydro-2,5,8,11-benzodioxadithia-cyclotetradecine-6,7-dicarbonitrile (3) or (6Z)-1,3,4,9,10,12-hexahydro-2,5,8,11-benzotetrathiacyclotetradecine-6,7-dicarbonitrile (5) in the presence of magnesium butanolate. The precursors were prepared from disodium salt of dithiomaleonitrile and o-xylenebis(1-chloro-3-oxapentane) (2) or o-xylenebis(1-chloro-3-thiapentane) (4). The metal-free porphyrazines are obtained by the treatment of these magnesium porphyrazines with trifluoroacetic acid. These new compounds are characterized by a combination of elemental analysis and 1H, 13C NMR, IR, UV–vis and MS spectral data.