Five spectroscopic techniques were used to investigate the interaction of astilbin (ASN) with human serum albumin (HSA). UV–vis absorption measurements prove that ASN–HSA complex can be formed. The analysis of fluorescence spectra reveal that in the presence of ASN, quenching mechanism of HSA is considered as static quenching. The quenching rate constant kq, KSV and the binding constant K were estimated. According to the van't Hoff equation, the thermodynamic parameters enthalpy change (ΔΗ) and entropy change (ΔS) were calculated to be −12.94 kJ mol−1 and 35.92 J mol−1 K−1, respectively. These indicate that the hydrophobic interaction is the major forces between ASN and HSA, but the hydrogen bond interaction cannot be excluded. The changes in the secondary structure of HSA which was induced by ASN were determined by circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy.Graphical abstractIn this paper, the interaction of HSA with ASN was systematically studied under simulated physiological conditions by using UV–vis absorption, CD, FT-IR, fluorescence and Raman spectroscopic approaches. The quenching constant kq, KSV and the binding constant K were estimated. The changes in the secondary structure of HSA were studied by Circular dichroism (CD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The UV–visible absorption spectra of HSA in the absence and presence of different concentration of ASN (1) and fluorescence spectra of HSA in the absence and the presence of ASN (2).Highlights► Interaction of ASN and HSA has been studied by five spectroscopic techniques. ► Hydrophobic interaction is the major forces between ASN and HSA. ► Binding of ASN induced the changes in the secondary structure of HSA.

A 2-D cobalt–organic framework formulated as [Co(bdc)(bptb)]n (1), built from a mixed 1,2-benzenedicarboxylate anion (bdc), 1,4-bis(5-(4-pyridyl)-1H-1,2,4-triazol-3-yl)benzene (bptb), and cobalt salt, has been hydrothermally synthesized and characterized. Complex 1 has a [Co(bdc)]n chain structure in which the chains are isolated by the bptb ligands in a 2-D wave-like architecture. The magnetic behavior of complex 1 was studied, and it indicated the coexistence of spin-canted weak ferromagnetism with TN = 10 K and long-range magnetic ordering.Graphical abstractIn this paper, a 2-D Cobalt-organic framework formulated as [Co(bdc)(bptb)]n (1), built from a mixed 1,2-benzenedicarboxylate anion (bdc), 1,4-bis(5-(4-pyridyl)-1H-1,2,4-triazol-3-yl)benzene (bptb), and cobalt salt, has been hydrothermally synthesized and characterized. Complex 1 indicated the coexistence of spin-canted weak ferromagnetism with TN = 10 K and long-range magnetic ordering.Highlights► A 2-D coordination polymers with new mixed-ligand system have been synthesized. ► Complex 1 indicated spin-canted weak ferromagnetism with TN = 10 K, and long-range magnetic ordering. ► Bptb is a long bent linker.

Based on 5-mercapto-1H-tetrazole-1-methanesulfonic acid disodium salt (Na2mtms) and 4,4′-bipyridine (bpy) as ligands, four new transition metal complexes, namely {[Cd2(mtms)(bpy)2(OAc)2]·H2O}n (1), {[Cd(mtms)(bpy)2(H2O)2]2·bpy·4H2O}n (2), {[Zn2(μ2-OH)(mtms)(bpy)3(H2O)]·ClO4·H2O}n (3), and {[Co(mtms)2(bpy)(H2O)2]·[Co(bpy)2(H2O)4]·H2O}n (4), have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 features a pillared-layer coordination architecture linked by acetate, mtms, and bridging bpy ligands. Complex 2 has a 1D polymeric structure with [Cd(mtms)(bpy)2(H2O)2] as the repeating unit; these infinite chains are further connected into a 3D supramolecular framework through π–π stacking of bpy ligands. In complex 3, the mtms ligand combined with μ2-OH bridges two Zn atoms to form a dimer structure, which is different from that of complex 2. Complex 4 shows a 3D supramolecular network containing infinite [Co(mtms)2(bpy)(H2O)2]2− anionic chains and free [Co(bpy)2(H2O)4]2+ cationic components. The luminescence properties of 1 and 2 and the electrochemical properties of 3 are reported.

Four bent ligands, (i) 4,4′-abpt, (ii) 4,4′-Hbpt, (iii) 3,4′-Hbpt, and (iv) 3,3′-Hbpt, as well as H2suc (succinic acid) have been utilized to construct seven coordination polymers: [Co(suc)(4,4′-abpt)(H2O)2]·H2O (1), [M(suc)(4,4′-Hbpt)(H2O)]·2H2O (M = Co for 2, Ni for 3), [Cd(suc)(4,4′-Hbpt)2(H2O)2] (4), [Co(suc)(3,4′-Hbpt)(H2O)3]·H2O (5), [Zn(suc)(3,4′-Hbpt)] (6), and [Zn(suc)0.5(3,3′-bpt)(H2O)] (7) (4,4′-abpt = 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole, 4,4′-Hbpt = 1H-3,5-bis(4-pyridyl)-1,2,4-triazole, 3,4'-Hbpt = 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole, and 3,3′-Hbpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazole). The crystal structure analysis reveals that 1–3 form similar two-dimensional (2D) layer structures, where the adjacent metal centers are connected by a syn–anti carboxylate bridge from suc ligands to furnish a succinate-metal chain, which is further interlinked by bent ligands. 4–7 form different 1D chains via suc anions, and bpt isomers display versatile coordination modes. The magnetic behavior of compounds 1–3 and 5 was studied, and it indicated the existence of interesting spin-canting behavior, where the bent ligands tilting the neighbor metal center could give further contribution to the canting effect. In addition, the luminescent properties of 4, 6, and 7 have been investigated in the solid state at room temperature.

Polydatin is a traditional Chinese medicine which shows effective biological activity as antimicrobial and antiviral agent. The secondary structure changes of bovine serum albumin (BSA) were investigated by the methods of Fourier transform infrared spectroscopy (FT-IR), circular dichroism (CD) and Raman spectroscopy. The experimental results indicated that polydatin changed the secondary structure of BSA. The presence of polydatin decreased α-helix content of BSA. The conformations of disulfide bridges and the microenvironment of Tyr, Trp residues were also changed.Graphical abstractStructural changes of bovine serum albumin caused by the binding of polydatin have been studied by FT-IR, CD and Raman spectroscopy. Polydatin changed the conformations of BSA with decreasing of α-helix content and changing of the conformations of disulfide bridges.Highlights► The interaction between bovine serum albumin (BSA) and polydatin has been studied. ► The secondary structure changes of BSA were investigated by multispectroscopy. ► Polydatin decreased α-helix content and increased β-sheet and β-turn structures of BSA. ► The conformations of disulfide bridges and the microenvironment of Tyr, Trp were also changed.

The homo- and heteronuclear ionic complexes, {[Zn6M(PMTA)6][M(H2O)4]2·xH2O}n [H3PMTA = N-phosphonomethyl-1,3-thiazolidine-4-carboxylic acid; M = Co, x = 10 (1); M = Zn, x = 8 (2)], have been synthesized by hydrothermal reactions. X-ray crystallographic analysis revealed that both complexes have similar topologies, in which nonanuclear [Zn6M(PMTA)6][M(H2O)4]2 cluster units are linked by syn-anti carboxylate groups to form one-dimensional nanochains.

Two nickel(II) complexes [Ni(Hpiotsc)2(NO3)2] (1), [Ni(Hpiotsc)2(NO3)2]·H2O (2) were synthesized and characterized by single crystal X-ray diffraction, IR, and thermal analyses. The geometry of the nickel(II) atom in two complexes is a distorted octahedron with ONS atoms of two neutral ligands. The antimicrobial activities of complex 1 were evaluated by the MIC (minimum inhibitory concentration) against five bacteria. The six-coordinate complex 1 did not inhibit the growth of the test organisms.