Clamshell‐type Bis‐phthalocyanine with Tetrachlorocyclotriphosphazene Intramolecular Bridge: Synthesis and Structural Evaluation by DFT, NMR and Optical Spectroscopy

An interaction of 2-hydroxy-9(10),16(17),23(24)-tri-tert-butyl-29H,31H- phthalocyanine (1) with hexachlorocyclotriphosphazene (phosphonitrilic chloride trimer) produced, along with the A(3)B type low-symmetry monophthalocyanine (monomer 2), a bis-derivative 3 with spectral characteristics such as that of most clamshell-type phthalocyanines (typically, H-dimers). The reaction can be considered conditionally selective. DFT calculations showed the possibility of the existence of several isomers. Based on the UV-Vis, fluorescent and NMR studies, we found that 3 was obtained as an inseparable mixture of three diastereomers-achiral cis-isomer and two chiral trans-isomers. DFT analysis has also shown that cis-isomer can exist as two rotamers-parallel and oblique, by an analogy with the cofacial J-type dimers that we obtained earlier.