1334285-75-4Relevant academic research and scientific papers
Crucial influence of the intramolecular hydrogen bond on the coordination mode of RC(S)NHP(S)(OiPr)2 in homoleptic complexes with Ni II
Babashkina, Maria G.,Safin, Damir A.,Srebro, Monika,Kubisiak, Piotr,Mitoraj, Mariusz P.,Bolte, Michael,Garcia, Yann
, p. 545 - 555 (2013/05/09)
Reaction of the deprotonated N-thiophosphorylated thioureas RC(S)NHP(S)(OiPr)2 [R = EtNH (HLI), iPrNH (HL II), Et2N (HLIII), 2,5-Me2C 6H3NH (HLIV), 4-Me2NC 6H4NH (HLV)] with NiII leads to complexes of the formula [NiLI-V2]. The molecular structures of the complexes in the solid were elucidated by single-crystal X-ray diffraction analysis. In the complexes, the metal atom is found to be in a square-planar trans-N2S2 ([NiLII,IV 2]) environment formed by the C=S sulfur atoms and the P-N nitrogen atoms, or in a square-planar trans-S2S′2 ([NiL I,III2]) environment formed by the C=S and P=S sulfur atoms of two deprotonated ligands. Reaction of deprotonated N-thiophosphorylated thiourea HLV with NiCl2 leads to violet [Ni(L-1,3-N,S)2] or dark violet [Ni(L-1,5-S,S′) 2]·(CH3)2C=O crystals that were isolated by recrystallization from a mixture of CH2Cl2 or acetone, respectively, and n-hexane. DFT calculations confirmed that the [Ni(L I,II,IV,V-N,S)2] conformers are more stable (by 5-7 kcal/mol) than [Ni(LI,II,IV,V-S,S′)2], whereas [Ni(LIII-N,S)2] is less stable (by 7-9 kcal/mol) than [Ni(LIII-S,S′)2]. The main reason for higher stability of the 1,3-N,S versus 1,5-S,S′ isomers is the formation of intramolecular N-H...S=P hydrogen bonds. The same hydrogen bonds are impossible in complex [NiLIII2]. In solution, complex [NiLIII2] has revealed an exclusively 1,5-S,S′ coordination, whereas compounds [NiLI,II,IV,V2] reveal at least two isomers in the 1H and 31P{1H} NMR spectra. The major species is assigned to the 1,3-N,S-coordinated isomer, and the minor signals are assigned to the 1,5-S,S′ isomer, which was confirmed by UV/Vis spectroscopic results. The electrochemical measurements reveal reversible one-electron reduction and irreversible oxidations both assigned to ligand-centred processes. Ligand-based oxidation processes agree well with TD-DFT results. Reaction of deprotonated RC(S)NHP(S)(OiPr)2 [R = EtNH (HLI), iPrNH (HLII), Et2N (HLIII), 2,5-Me2C6H3NH (HLIV), 4-Me 2NC6H4NH (HLV)] with NiII leads to [NiLI-V2]. The metal atom is found to be in a square-planar trans-N2S2 ([NiLII,IV 2]) or in a square-planar trans-S2S′2 ([NiLI,III2]) environment. Reaction of LV with NiII leads to [Ni(L-1,3-N,S)2] or [Ni(L-1,5-S,S′) 2]·(CH3)2C=O crystals. Copyright
