Reaction of tin(iv) phthalocyanine dichloride with decamethylmetallocenes (M = CrII and CoII). Strong magnetic coupling of spins in (Cp*2Co+){SnIVCl2(Pc˙3−)}˙−·2C6H4Cl2

Abstract

The reaction of tin(IV) phthalocyanine dichloride {Sn^IVCl₂(Pc²⁻)} with decamethylmetallocenes (Cp*₂M, M = Co, Cr) has been studied. Decamethylcobaltocene reduces Sn^IVCl₂(Pc²⁻) to form the (Cp*₂Co⁺){Sn^IVCl₂(Pc˙³⁻)}˙⁻·2C₆H₄Cl₂ (1) complex. The negative charge of {Sn^IVCl₂(Pc˙³⁻)}˙⁻ is delocalized over the Pc macrocycle providing the alternation of the C–N(imine) bonds, the appearance of new bands in the NIR range and a strong blue shift of both the Soret and Q-bands in the spectrum of 1. The magnetic moment of 1 is equal to 1.68μ_B at 300 K, indicating the contribution of one S = 1/2 spin of the Pc˙³⁻ macrocycles. These macrocycles form closely packed double stacks in 1 with effective π–π interactions providing strong antiferromagnetic coupling of spins at a Weiss temperature of −80 K. Decamethylchromocene initially also reduces Sn^IVCl₂(Pc²⁻) to form the [(Cp*₂Cr⁺){Sn^VICl₂(Pc˙³⁻)}˙⁻ complex but further reaction between the ions is observed. This reaction is accompanied by the substitution of one Cp* ligand of Cp*₂Cr by chloride anions originating from {Sn^IVCl₂(Pc˙³⁻)}˙⁻ to form the complex {(Cp*CrCl₂)(Sn^IV(μ-Cl)(Pc²⁻))}·C₆H₄Cl₂ (2) in which the (Cp*CrCl₂) and {Sn^IV(Pc²⁻)} species are bonded through the μ-bridged Cl⁻ anion. According to the DFT calculations, this reaction proceeds via an intermediate [(Cp*₂CrCl)(SnClPc)] complex.