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

作者：Safin Damir A; Babashkina Maria G; Mitoraj Mariusz P; Kubisiak Piotr; Robeyns Koen; Bolte Michael; Garcia Yann

来源：Inorganic Chemistry Frontiers, 2016, 3(11): 1419-1431.

DOI：10.1039/c6qi00298f

A new N-thiophosphorylated thiourea (1-pyrene) NHC(S) NHP(S)(OiPr)(2) (HL) has been synthesized. The molecular structure of HL was elucidated by X-ray diffraction revealing a linear intramolecular hydrogen bond. Additionally, its crystal structure is stabilized by two intermolecular hydrogen bonds, which in turn leads to a centrosymmetric R-2(2) (8) dimer formation. These dimers are packed into polymeric chains through pi center dot center dot center dot pi stacking interactions between the pyrene rings. The reaction of the deprotonated HL with Ni-II leads to the Ni-II complex ([NiL2]). The crystal structure of [NiL2] exhibits a centrosymmetric homoleptic structure, where the Ni-II ion is coordinated in a square-planar fashion with the ligands arranged in a trans-N2S2 configuration. The pyreneNH protons in [NiL2] are involved in intramolecular hydrogen bonds of the pyreneN-H center dot center dot center dot S=P type. Molecules of [NiL2] form pi center dot center dot center dot pi stacking interactions between the pyrene rings, yielding 1D polymeric chains similar to those observed in the structure of HL. These pi center dot center dot center dot pi stacked 1D polymeric chains are linked to each other through C-H center dot center dot center dot S and anagostic C-H center dot center dot center dot Ni interactions, yielding 2D sheets. Hirshfeld surface analysis showed that the structures of both HL and [NiL2] are highly dominated by H center dot center dot center dot H, H center dot center dot center dot C, H center dot center dot center dot S and C center dot center dot center dot C contacts and also characterized by H center dot center dot center dot O and H center dot center dot center dot N contacts. The molecular surfaces of HL and [NiL2] also contain O center dot center dot center dot S and H center dot center dot center dot Ni contacts, respectively. Both HL and [NiL2] were found to be emissive in CH2Cl2 solution, which is due to the concentration dependent emission of the pyrene monomer and excimer. It was established that the latter fluorescence is due to the intermolecular excimer formation. The DFT calculations allowed us to confirm the aggregation ability of the synthesized species in solution through the numerous non-covalent interactions C-H center dot center dot center dot S, C-H center dot center dot center dot Ni and C-H center dot center dot center dot pi, which, in turn, might be responsible for the concentration dependent photophysical properties.

• 出版日期2016