A novel CuII–azido-pyrazine framework with 3D-42.63.8-topology: Crystal structure and magnetic property

Crystal structure, Hirshfeld surfaces and DNA cleavage investigation of two copper(II) complexes containing polypyridine and salicylide ligands

Two copper complexes 1 [Cu2(phen)2(salicylaldehyde)2(ClO4)2] and 2 [Cu2 (2,2'-dipyridyl)2(salicylaldehyde)2(ClO4)2] have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. These two complexes were display binuclear structure with Cu(II) ions in distorted octahedral environment but antipodal orientation of the binuclear units between them. Molecular Hirshfeld surfaces revealed that the crystal structures of 1 and 2 were supported mainly by H-H, C-H⋯π, π⋯π (C-C), and C-H⋯O intermolecular interactions. DNA cleavage experiments of complexes 1 and 2 revealed that these complexes can intercalation with DNA.

A thermally labile copper (II) complex with hetero N- and O-donor ligands: crystal structure, Hirshfeld surfaces, thermal and luminescent properties

A new complex ([Cu(L1)2(H2O]2]⋅2H2O, 1) derived from a hetero N- and O-donor ligand 5-methyl-imidazole-3-carboxylic acid (L1H) has been synthesized and characterized. Comparisons between [Cu(L1)2(H2O]2]⋅2H2O, [Co(L2)(H2O]2⋅H2O (2), and [Cu(L2)2H2O]⋅H2O (L2H=5-methyl-isoxazole-3-carboxylic acid) revealed that the coordinated water molecules play a key role in the construction of crystal structures: two coordinated water molecules in the axial positions lead to single-deck 1D chain and 3D motif while one coordinated water molecule resulted to double-deck 1D chain and 2D stacking motif. Molecular Hirshfeld surfaces revealed that complexes 1 and 2 were supported mainly by H-H, C-H⋯π, and O-H⋯O intermolecular interactions. The room temperature solid state luminescent properties of complexes 1 and 2 were all shown as two distinct bands, which attribute to ligand-metal charge transfer and metal purterbed ligand centered emission.

Positions of amino groups on ammonium salts tunes the conformations of crown ethers: crystal structures, Hirshfeld surfaces and spectroscopic studies

The position of the amino group on the ammonium salt plays a key role in the supramolecular structure and conformation of the crown ether.

Two new metastable forms of 6-chloroquinolin-2(1H)-one: crystal structure, Hirshfeld surfaces and spectroscopic studies

Two new metastable crystalline forms of 6-chloroquinolin-2(1H)-one (forms II and III), which were induced by two kinds of 3D inorganic anions (ClO4- and BF4-), have been prepared and characterized in this work. We performed single-crystal diffraction, X-ray powder diffraction (XRPD), Hirshfeld surfaces, solid-state vibrational spectroscopy (IR) and thermal analysis (DSC, TGA) to these two new forms as well as the original one (form I). Form I featured with 1D chain, while form II and III featured with dimeric unit with stronger π⋯π and hydrogen bonds interactions. The 3D inorganic anions force the self-assemble behavior of 6-chloroquinolin-2(1H)-one molecules from 1D chain structure (form I) to dimeric unit (forms II and III) due to their large steric hindrance, and different anions induced different orientations for dimeric unit. These transformations lead to the increase of N-H⋯O, π⋯π, and Cl-Cl intermolecular interactions, which lead to blue shift of IR spectra in 1700-1500 cm(-1) region as well as luminescence peaks, while red shift of IR spectra in 650-550 cm(-1) region.

Co-crystallization of pyridine-2-carboxamide with a series of alkyl dicarboxylic acids with different carbon chain: crystal structure, spectroscopy and Hirshfeld analysis

Three new co-crystals: pyridine-2-carboxamide-succinic acid (1), pyridine-2-carboxamide-glutaric acid (2) and pyridine-2-carboxamide-adipic acid (3) have been synthesized and characterized by single-crystal X-ray diffraction, TGA/DSC measurements, solid-state vibrational spectroscopy (IR and Raman) in this work. The investigation revealed that the carbon chain length of these alkyl acids changed the connecting motif of co-crystals 1-3 from trimer to 1D chain, and the formation of hydrogen bond interaction of pyridine-2-carboxamide with these alkyl acids lead to red shift of stretching vibration of NH2 and OH groups in IR and Raman spectra. We also studied Hirshfeld surface and UV properties of co-crystals 1-3, and we found that the carbon chain length lead to decrease of close intermolecular interactions, and the formation of hydrogen bond interaction lead to red shift of UV spectra.