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

Cyclic
tetramerization of 3-(dibutylamino)­phthalonitrile in refluxing n-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(C4H9)2]4-C4} (2). This, in
combination with its much superior crystallinity over the remaining
three isomers, renders the easy isolation of 2 only through
two simple recrystallizations from THF and methanol. Treatment of 2 with trifluoroacetic acid induced the isolation of metal-free
1,8,15,22-tetrakis­(dibutylamino)­phthalocyanine, H2{Pc­[α-N­(C4H9)2]4-C4} (1), which further reacted with M­(OAc)2·nH2O (M = Ni, Zn) in refluxing n-pentanol, giving the 1,8,15,22-tetrakis­(dibutylamino)­phthalocyaninato
metal complexes M­{Pc­[α-N­(C4H9)2]4-C4} (M = Ni (3), Zn (4)). 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.