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

Abstract

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 A3B 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.

Deviation from Beer's law and relationship of aggregation with the effective TPA coefficient: UV-vis studies on a series of low symmetry monophthalocyanines bearing a cyclotriphosphazene substituent

“…Our recent works show the advantage of introducing cyclic phosphazene into the phthalocyanine structure as a free substituent 14 and also as a spacer linking two macrocycles in one molecule. 15 The presence of active chlorine atoms in the phosphazene structure opens up the possibility for obtaining complicated macrocyclic ensembles, and is important for fine-tuning the NLO response. Therefore, we are finding out a specific meaning in continuing the work that has been started.…”