Ruiying Wang

Synthesis and Crystal Structure of A Novel Mixed-valent Tri-copper Complex of 4′-p-Tolyl-2,2′:6′,2′-terpyridine

Two copper complexes of 4′-p-tolyl-2,2′:6′,2′-terpyridine (ttpy), namely, monomer [Cu II (ttpy)Cl2] (1) and trinuclear complex [Cu II (ttpy)Cl2]. [Cu II Cu I (ttpy)Cl3] (2), were prepared through solvothermal synthesis and structurally determined by single crystal X-ray diffraction. Compound 1 obtained by another way before was firstly solvothermally synthesized and structurally investigated herein. In 1 metal center Cu2+ ligated by a ttpy molecule and two chloride ions is in a distorted square pyramidal geometry. However, complex 2 is a novel mixed-valent tri-copper complex which contains a monomeric [Cu II (ttpy)Cl2] part being very similar to 1, and a mixed-valent chloride-bridged di-nuclear [Cu II Cu I (ttpy)Cl3] part, presented interesting co-crystallization behavior.

Co−MOFs with 1,1′-(5-methyl-1,3-phenylene)bis(1H-imidazole) and aromatic carboxylates as coligands: synthesis, structure, and spectroscopic and thermal characterizations

Abstract Four cobalt(II) compounds, [Co(Bim)(IA)(H2O)2]n·0.5nH2O (1), [Co(Bim)(MA)(H2O)2]n (2), [Co2(Bim)2(MA)2]n·nH2O (3), and [Co3(Bim)4(TA)2(H2O)2]n·2.5nH2O (4), have been synthesized by solvothermal reactions of cobalt(II) salts with 1,1′-(5-methyl-1,3-phenylene)bis(1H-imidazole) [Bim] and aromatic polycarboxylic acids (H2IA = isophthalic acid, H2MA = 5-methylisophthalic acid, and H3TA = trimesic acid) as coligands. The four complexes were characterized by IR and UV−vis spectra, elemental analyses, X-ray powder and single-crystal diffractions, and thermogravimetric analyses (TGAs). 1 features a zigzag polymeric macrocycle chain containing a nanotubular channel, which is constructed by bridging the folded 20-membered macrocyclic [Co2(Bim)2] subunits with IA ligands. 2 represents a double-chain structure containing 18-membered macrocyclic [Co2(Bim)(MA)] subunits. Both 3 and 4 are 2-D porous coordination polymers but have different architectures. In 3, cage-like [Co4(Bim)2(MA)4] subunits are 4-connected nodes that are further bridged by another half-set of Bim ligands to form a 2-D helical structure containing one-dimensional achiral channels and alternately arranged left- and right-handed helical tubular channels. In 4, Bim ligands bridge three crystallographically independent Co centers into sharply distorted left- and right-handed helices which are further connected by TA ligands to form a meso layer about 3.0 nm monolayer thickness with a unique (3,4)-connected topology. The structural diversities of coordination polymers 1–4 are tuned by the flexible coordination number of Co and coligand polycarboxylates. Thermal analyses show that the main frameworks of all compounds remain stable to 352 °C. Moreover, the interesting color changes of crystals 1–4, varying from pink to purple and dark blue, result from the d → d* transitions of chromophoric Co2+ in different coordination geometries as determined by the UV–vis spectra in combination with crystal structure analyses.

A New Metal–Organic Molecular Square Based on Imidazole-4,5-dicarboxylicate

A new metal–organic molecular square of imidazole-4,5-dicarboxylic acid (H3IDC), namely, [Co4(py)8(HIDC)4] (1) was prepared (py = pyridine), and structurally determined by single-crystal X-ray diffraction analysis, IR, and elemental analysis. In compound 1, doubly deprotonated ligands HIDC2− in a bis(chelating) coordination mode of μ-kN,O:kN′,O′ link four Co(II) ions together to form a slightly distorted molecule square. Additionally, the electrochemical property of 1 was also measured.