Synthesis and characterization of [H2NC(S)NP(S)(OiPr)2]− complexes of Co(II), Ni(II), Zn(II) and Cd(II)

Chirality Control in Crystalline Ni(II) Complexes of Thiophosphorylated Thioureas

Chirality control over the formation of Ni(II) complexes with chiral thiophosphorylated thioureas was achieved via breaking the symmetry of nickel coordination geometry by the introduction of the pyridine ligand, while centrosymmetric meso-complexes are formed from racemic ligands in case of square-planar nickel coordination. Centrosymmetric heterochiral arrangement is observed in crystals of ligands themselves through N–H⋅⋅⋅S hydrogen bonds in intermolecular dimers. Molecular homochirality in tetragonal pyramidal complexes is further transferred to supramolecular homochiral arrangement via key–lock steric interactions.

An intermolecular pyrene excimer in the pyrene-labeled N-thiophosphorylated thiourea and its nickel(ii) complex

(1-pyrene)NHC(S)NHP(S)(OiPr)₂ (HL) and its Ni^II complex ([NiL2]) have been synthesized. Both HL and [NiL2] were found to be emissive in solution of CH₂Cl₂, which is due to the concentration dependent emission of the pyrene monomer and excimer.

Complexation properties of N-thiophosphorylated thiourea 2-PyNHC(S)NHP(S)(OiPr)2 towards Ni(II)

Reaction of the deprotonated N-thiophosphorylated thiourea 2-PyNHC(S)NHP(S)(OiPr)2 (HL) with NiCl2 leads to the complex [Ni{2-PyNHC(S)NP(S)(OiPr)2}2] ([NiL2]) with unprecedented 1,5,7-N,N′,S-coordination of the ligand. Recrystallization of [NiL2] from a mixture of CH2Cl2–n-hexane or acetone–n-hexane leads to [Ni(L-1,5,7-N,N′,S)2]·CH2Cl2 and [Ni(L-1,5,7-N,N′,S)2], respectively. The latter complex, in turn, shows a temperature-induced polymorphism. [NiL2] in solution shows a paramagnetic distorted octahedral structure where the metal center is coordinated through the nitrogen atoms of the phosphorylamide and pyridyl group functions, and oxygen atoms of the phosphorylamide unit. Furthermore, in the solid state at low temperature, [Ni(L-1,5,7-N,N′,S)2] is shown from high-frequency EPR measurements to possess an S = 1 ground state with large anisotropy.