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Two new phenoxo-bridged heterobimetallic [Zn(II)2M(II)] (M = Sr and Ba) salamo-based complexes, [{Zn(L)(μ2-OAc)}2Sr]·0.33CH3OH·H2O (1) and [{Zn(L)(μ2-OAc)}2Ba] (2), have been designed, self-assembled and characterized by elemental analysis, FT-IR and UV-Vis spectroscopy, X-ray crystallography, Hirshfeld surfaces analyses, and Density Functional Theory (DFT) calculations. The results of UV and fluorescence titration experiments have demonstrated that the coordination ratio of the ligand H2L to Zn(II) has been 1 : 2 in the L–Zn(II) precursor. However, X-ray crystallographic analysis indicates the coordination ratio of H2L to Zn(II) as 1 : 1 in the complexes 1 and 2. Coordination environments of the complexes 1 and 2 are almost similar. The complex 1 has an asymmetric heterotrinuclear structure, while the complex 2 is formed as the symmetric heterotrinuclear structure. Fluorescence spectra demonstrate that fluorescence of the ligand is almost completely quenched due to coordination of Zn(II) atoms with H2L. According to DFT calculations chemical stability of the complexes 1 and 2 is higher than that of H2L. [ABSTRACT FROM AUTHOR]

A novel tetranuclear Ni(II) complex [Ni4(L)2(N3)4Cl(MeOH)3]·CH3COCH3 is synthesized via a symmetrical salamo-based ligand H2L, NiCl2·6H2O, and NaN3. The structure is characterized by elemental analyses, IR and UV-Vis spectroscopy, and X-ray diffraction analysis. The X-ray crystal analysis shows that Ni(II) atoms in the Ni(II) complex have distorted octahedral geometries. It is the key factor that the ligand containing 3-position methoxy groups gives rise to the formation of the tetranuclear Ni(II) complex. When anions are used to bridge two Ni2 atoms, there are two symmetrical open cubic structures. The Ni(II) complex forms a 3D supramolecular structure through intermolecular hydrogen bond interactions. Using the Hirshfeld surface to clarify interactions between the molecules, the percentages of C–H/H–C, O–H/H–O, and H–H/H–H contacts are calculated as 19.0%, 15.3%, and 54.0%, respectively. Density functional theory (DFT) studies show that the stability of the Ni(II) complex is much higher than that of H2L. The calculation of the fluorescence titration experiment can give K = 1.05·108 M–1, which further proves the stability of the Ni(II) complex. [ABSTRACT FROM AUTHOR]

A novel two-dimensional Zn(II) coordination polymer [Zn(II) CP], [{Zn(L)Zn(OAc–)(µ-OAc–)}4]n· 2nCH3CH2OH has been self-assembled from Zn(OAc)2·2H2O. It contains pyridine-terminal salamo-type ligand H2L. Structure of the product has been determined. The Zn(II)CP contains two kinds of Zn(II) ions of different coordination modes. The Zn1 center is characterized by five-coordinated triangular biconical geometry. The Zn2 center is a six-coordinated octahedral center. Using these as junction points and the fully deprotonated ligand (L)2– moieties containing pyridine-terminal as a linker, the 2-D coordination polymer with two kinds of different pores [27.47 × 11.77(23) Å2; 11.97 × 4.51(17) Å2] has been obtained. The Zn(II) CP can fluoresce green and be used in fluorescent materials. Short-range interactions on Zn(II) CP surface have been studied by Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

A structurally novel Cd(II) coordination polymer (CP), [Cd(H2L)2(NCS)2]n, has been self-assembled from a newly designed salamo-like ligand H2L bearing double terminal pyridine groups, Cd(II) and KSCN. The Cd(II) ion is not located in the N2O2 cavity of the ligand H2L and forms a six-coordinate octahedral geometrical configuration. Using Cd(II) ion as a node, the undeprotonated salamo-like ligand H2L units extend in space to give a Cd(II)CP with a 2D pore structure. Spectroscopic analysis of the ligand H2L and its Cd(II)CP is performed using IR, UV-Vis and fluorescence spectroscopy. Various short-range interactions in the Cd(II)CP are investigated on the basis of Hirshfeld surfaces analysis. [ABSTRACT FROM AUTHOR]