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Two new bimetallic molecular squares constructed by di(2-pyridylcarbaldehyde)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine (H2L), namely [Cu2(HL)2](ClO4)2·6H2O (1) and [Zn2(HL)2](ClO4)2·2H2O (2), have been synthesized and characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The architectures of the two bimetallic squares are mainly determined by the cooperation of the metal’s coordination modes and the conformations of H2L. In 1, the ligand-adopted tridentate plus bidentate bridging modes to give a double helicate, in which two copper(II) ions exhibited two different coordination environments, hex-coordination and penta-coordinated, respectively. While in 2, the ligand-adopted bistridentate bridging modes also to form a double-helicate, in which two zinc(II) ions have the same distorted octahedral geometry. Very interestingly, the overall three-dimensional structures of 1 and 2 contain one-dimensional channels occupied by anions and solvents with H-bonds between square cations and anions. In addition, the solid-state photoluminescent properties of the ligand, complexes 1 and 2 were also studied. The variable-temperature magnetic measurement for the complex 1 shows very weak antiferromagnetic interaction between Cu(II) centers.

Two supramolecular complexes Ni[(Py)2C(OH)2]2·(CH3COO)2·4H2O 1 and Co[(Py)2C(OH)2]2·(CH3COO)2·2H2O 2 have been synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The X-ray diffraction analysis indicates that the center metal (Ni2+ and Co2+) ions having the same coordination environments are chelated by two pyridyl N atoms and a hydroxyl O atom of the gem-diol ligand in an octahedral geometry. In 1, the lattice water molecules form infinite single helical chains, while in 2, two lattice water molecules are discrete. In their crystal structures, intermolecular O–H···O and C–H···O hydrogen bonds form an extensive three-dimensional network, which consolidates the crystal packing.

(±)-2,2′-dihydroxy-1,1′-binaphthyl (binol) co-crystallized with 1,10-phenanthroline-5,6-dione and acridine to afford co-crystals (Binol)·(1,10-phenanthroline-5,6-dione) 1 and (Binol)·(acridine)2 2, respectively. Co-crystal 1 crystallizes in space group P-42(1)c, with a = 14.9921(4), b = 14.9921(4), c = 20.8102(12) A. Co-crystal 2 crystallizes in space group P2/c, with a = 17.8004(19), b = 10.0093(11), c = 19.393(2) A, and α = γ = 90°, β = 103.187(2)°. In co-crystal 1, the components form an infinite 1D polar array; whereas in 2, the components form discrete three-component aggregates. Molecular recognition and supramolecular self-assemblies of (±)-2,2′-dihydroxy-1,1′-binaphthyl with aromatic aza compounds Baoming Ji, Shaobin Miao, Dongsheng Deng As a result of mutual recognition, (±)-binol with 1,10-phenanthroline-5,6-dione and acridine afforded co-crystals 1 and 2, respectively. In 1 the components form an infinite 1D polar array, whereas in 2 the components form discrete three-component aggregates.