First structurally characterized self-assembly of bipodal N-thiophosphorylated bis-thiourea with CoII: magnetic properties and thermal decomposition

Abstract

Reaction of piperazine with isothiocyanate (iPrO)₂P(S)NCS leads to N-thiophosphorylated bis-thiourea (iPrO)₂P(S)NHC(S)NC₄H₈NC(S)NHP(S)(OiPr)₂ (H₂2L). Recrystallization of H₂2L from DMSO leads to the formation of the new ligand (iPrO)₂P(S)NC₄H₈NP(S)(OiPr)₂ (1). Reaction of doubly deprotonated L with Co^II leads to the [Co₂22L₂22] complex. The thermal properties of [Co₂22L₂22] in an air atmosphere were studied by means of TGA with the observed final residue corresponding to [CoPS₃]₂. The crystal structure of [Co₂22L₂22] was elucidated by single crystal X-ray diffraction. Two metal cations are in a tetrahedral 1,5-S₂S′₂ environment formed by the CS and PS sulfur atoms. Investigation of the temperature dependence of the magnetic susceptibility is consistent with two effectively non-interacting Co^II S = 3/2 ions.