Coordination Complexes of Titanium(IV) and Indium(III) Phthalocyanines with Carbonyl-Containing Dyes: The Formation of Singly Bonded Anionic Squarylium Dimers.

Reduction methods for the preparation of coordination complexes of titanium(IV) and indium(III) phthalocyanines (Pc) with organic dyes such as indigo, thioindigo, and squarylium dye III (SQ) have been developed, which allow one to obtain crystalline {cryptand(K+ )}{(cis-indigo-O,O)2- TiIV (Pc2- )}(Cl- )⋅C6 H4 Cl2 (1), {cryptand(K+ )}{(cis-thioindigo-O,O)2- InIII (Pc2- )}- ⋅C6 H4 Cl2 (2), and {cryptand(K+ )}{[(SQ)2 -O,O]2- InIII (Pc2- )}- ⋅3.5 C6 H4 Cl2 (3) complexes. The formation of these complexes is accompanied by the reduction of the starting dyes to the anionic state. Transition of trans-indigo or trans-thioindigo to the cis conformation in 1 and 2 provides coordination of both carbonyl oxygen atoms of the dye to TiIV Pc or InIII Pc. SQ is reduced to the radical anion state and forms unusual diamagnetic singly bonded (SQ- )2 dimers in 3. These dimers have two closely positioned carbonyl oxygen atoms coordinated to InIII Pc. Dianionic Pc2- macrocycles have been found in 1-3. The complexes contain two chromophore molecules at one metal center. However, their optical spectra are defined mainly by absorption bands of the metal phthalocyanines.