Nonperipheral Tetrakis(dibutylamino)phthalocyanines. New Types of 1,8,15,22-Tetrakis(substituted)phthalocyanine Isomers

Cyclic tetramerization of 3-(dibutylamino)­phthalonitrile in refluxing <i>n</i>-pentanol in the presence of magnesium pentanoate afforded the four regioisomer-containing nonperipheral 1,8-/11,15-/18,22-/25-tetrakis­(dibutylamino)­phthalocyaninato magnesium complexes with the 1,8,15,22-tetrakis­(dibutylamino)­phthalocyanine isomer Mg­{Pc­[α-N­(C<sub>4</sub>H<sub>9</sub>)<sub>2</sub>]<sub>4</sub>-<i>C</i><sub>4</sub>} (<b>2</b>). This, in combination with its much superior crystallinity over the remaining three isomers, renders the easy isolation of <b>2</b> only through two simple recrystallizations from THF and methanol. Treatment of <b>2</b> with trifluoroacetic acid induced the isolation of metal-free 1,8,15,22-tetrakis­(dibutylamino)­phthalocyanine, H<sub>2</sub>{Pc­[α-N­(C<sub>4</sub>H<sub>9</sub>)<sub>2</sub>]<sub>4</sub>-<i>C</i><sub>4</sub>} (<b>1</b>), which further reacted with M­(OAc)<sub>2</sub>·<i>n</i>H<sub>2</sub>O (M = Ni, Zn) in refluxing <i>n</i>-pentanol, giving the 1,8,15,22-tetrakis­(dibutylamino)­phthalocyaninato metal complexes M­{Pc­[α-N­(C<sub>4</sub>H<sub>9</sub>)<sub>2</sub>]<sub>4</sub>-<i>C</i><sub>4</sub>} (M = Ni (<b>3</b>), Zn (<b>4</b>)). The full series of four 1,8,15,22-tetrakis­(dibutylamino)­phthalocyanine isomeric compounds have been characterized by a series of spectroscopic methods and single-crystal X-ray diffraction analyses. Obviously, the present result provides a simple and effective pathway for the synthesis and isolation of novel 1,8,15,22-tetrakis­(dibutylamino)­phthalocyanine isomeric derivatives, providing one step forward toward completing bis­(alkyl)­amino-incorporated phthalocyanine species.