Toward a More General Synthetic Route to Paramagnetic Solids Containing RCNSSS^•+ Radical Cations. A Structure−Property Correlation for RCNSSS^•+ (R = F₅C₂, Cl₃C)

Reaction of Cl3CN and F5C2CN with a 1:1 mixture of S4(AsF6)2 and S8(AsF6)2 affords the paramagnetic solids Cl3CNSSSAsF6 (1CCl3AsF6) and F5C2CNSSSAsF6 (1C2F5AsF6). Isotropic electron paramagnetic resonance spectra of 1CCl3AsF6 and 1C2F5AsF6 in SO2 consist of a single line with g = 2.01675 and 2.01580, respectively. The structure of 1CCl3AsF6 contains chains of radical cations with relatively close interchain interactions. In contrast, chains are isolated in 1C2F5AsF6. The magnetic behavior of both compounds was interpreted as that of 1D Heisenberg antiferromagnetic chains (1CCl3AsF6, J = −34 cm-1, θ = −9 cm-1, TIP = 0.00082, ρ = 0.012; 1C2F5AsF6, J = −21 cm-1, θ = −4.2 cm-1, TIP = 0.00092, ρ = 0.065). Density functional theory calculated and experimental magnetic coupling constants were in good agreement. The correlation between intermolecular S···S contacts and the strength of magnetic couplings was established.