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

Abstract

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) Ti (Pc )}(Cl )⋅C H Cl (1), {cryptand(K )}{(cis-thioindigo-O,O) In (Pc )} ⋅C H Cl (2), and {cryptand(K )}{[(SQ) -O,O] In (Pc )} ⋅3.5 C H Cl (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 Ti Pc or In Pc. SQ is reduced to the radical anion state and forms unusual diamagnetic singly bonded (SQ ) dimers in 3. These dimers have two closely positioned carbonyl oxygen atoms coordinated to In Pc. Dianionic Pc 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.

Metal Complexes of Indigo and of Some Related Ligands

“…In a Cp*Ir complex containing this cis ‐ N,N ‐dianionic indigo ligand and a tin(II) phthalocyanine radical anion two cis ‐ N,N ‐ indigo dianionic ligands are linked by a leuco cis ‐indigo dianionic ligand with strong N–O hydrogen bonding. Cis configuration ( O,O ‐bonding) of the reduced dianion of indigo has also been detected by Konarev and co‐workers in the phthalocyanine complex of titanium IV [( cis ‐leuco‐indigo‐2H + ‐ O,O ‐)‐Ti IV (phtalocyanine 2– ) (Scheme )], which was obtained by reduction of trans ‐indigo with vanadyl‐phtalocyaninine, using KC 8 followed by addition to a solution of TiCl 2 (phthalocyanine 2– ) …”

“…Additionally, one oxygen atom of thioindigo becomes a μ 2 ‐bridge to form a dimer with strong antiferromagnetic coupling of the two Cr 3+ cations (Scheme ]. The same O,O ‐coordinated thioindigo‐dianion [ cis ‐thioindigo] 2 is present in a phthalocycanine indium complex, which is formed by reduction of indium(III) chloride phthalocycanine with KC 8 in the presence of cryptand‐potassium and addition of thioindigo …”

Trinuclear coordination assemblies of low-spin dicyano manganese(ii) (S = 1/2) and iron(ii) (S = 0) phthalocyanines with manganese(ii) acetylacetonate, tris(cyclopentadienyl)gadolinium(iii) and neodymium(iii)

“…In this case, unpaired electrons are positioned either on the radical trianion Pc 3•− macrocycles or coordinated metal atoms (M). Different fragments (M) can be attached as follows: Fe(CO) 4 , CpMo(CO) 2 , Cp*RhCl 2 , Cp*IrCl 2 , CpFe(CO) 2 , Ru 3 (CO) 11 , Os 3 (CO) 10 Cl and others. 7 In this work, dicyano complexes of manganese(II) and iron(II) phthalocyanines as well as iron(II) hexadecachlorophthalocyanine have been obtained and studied.…”

“…Indigo and thioindigo dianions coordinate to the central metal atoms of MPcs, thereby combining phthalocyanines and organic dyes in one molecule. 4 Such assemblies can show thermoinduced charge transfer between ligands. 5 The magnetic properties of MPcs can be modified by the addition of metal-containing fragments bearing heteroatoms or cyano-ligands to the central metal atoms of MPcs.…”

Discovery and properties of a new indigoid structure type based on dimeric cis-indigos

“…Current cis-(O,O′) coordination reaction using parent indigo requires an extensive workup or a reductive method to bring two oxygen atoms close together. 71,72 However, one may access an easier interaction with the metal and avoid unwanted coordination modes using the tethered cis-indigoid structure. Prospective metals are Co, Zn, Cu and Ni where the complex formation was observed with the neutral β-diketone ligands.…”