Reaction of decamethylchromocene (Cp*Cr) with thioindigo (TI) yields a coordination complex {[TI-(μ-O), (μ-O)]Cp*Cr}·CH (1) in which one Cp* ligand in Cp*Cr is substituted by TI. TI adopts cis-conformation in 1 allowing the coordination of both carbonyl groups to chromium. Additionally, one oxygen atom of TI becomes a μ-bridge for two chromium atoms to form {[TI-(μ-O), (μ-O)]Cp*Cr} dimers with a CrCr distance of 3.12 Å. According to magnetic data, diamagnetic TI dianions and two Cr atoms with a high S = 3/2 spin state are present in a dimer allowing strong antiferromagnetic coupling between two Cr spins with an exchange interaction of -35.4 K and the decrease of molar magnetic susceptibility below 140 K. Paramagnetic TI˙ radical anions with the S = 1/2 spin state have also been obtained and studied in crystalline {cryptand[2,2,2](Na)}(TI˙) (2) salt showing that both radical anion and dianion states are accessible for TI.

Crystalline anionic salts of titanyl macrocycles with acceptor substituents or an extended π-system have been obtained for the first time: (PPN){O[double bond, length as m-dash]Ti(PcCl)} (1), (PPN){O[double bond, length as m-dash]Ti(Nc˙)}˙·2CHCl (2) and (PPN){O[double bond, length as m-dash]Ti(AceTPrzPz)}·1.3CHCl·0.8CHCN (3) where PPN is the bis(triphenylphosphoranylidene)ammonium cation, PcCl - 2,3,9,10,16,17,23,24-octachlorophthalocyanine; Nc - 2,3-naphthalocyanine, AceTPrzPz - tetra(acenaphthenopyrazino)porphyrazine. Salts 1-3 were obtained in the reduction of the parent titanyl macrocycles by fluorenone ketyl in the presence of an excess of PPNCl in o-dichlorobenzene with following precipitation of crystals with n-hexane. Reduction of macrocycles in 1-3 is accompanied by the appearance of intense NIR bands in the solid spectra at 963-1159 nm. It has been found that the extended π-system with linear annulation in {O[double bond, length as m-dash]Ti(Nc˙)}˙ provides the shift of the NIR band to smaller energies (1159 nm) in comparison with those in the spectra of {O[double bond, length as m-dash]Ti(Pc˙)}˙ (995-998 nm). Reduction of macrocycles leads also to the alternation of C-N bonds due to partial disruption of their aromaticity. The disruption is higher for the dianions in 1 and 3 in comparison with the radical anions in 2. One-dimensional π-π stacking chains and layers are formed in 1 and 3 with diamagnetic {O[double bond, length as m-dash]Ti(PcCl)} and {O[double bond, length as m-dash]Ti(AceTPrzPz)} dianions, respectively. Salt 2 contains nearly isolated [{O[double bond, length as m-dash]Ti(Nc˙)}˙] dimers with a strong π-π interaction between paramagnetic radical anion macrocycles. As a result, a transition from the triplet to singlet state with antiparallel ordering of spins within the dimers is observed in 2 below 200 K.