title: Structures and spectroscopic characterization of calcium chloride-nicotinamide, -isonicotinamide, -picolinamide and praseodymium bromide-nicotinamide complexes.
abstract: The coordination structures formed by calcium complexes with nicotinamide (na), isonicotinamide (ina) and picolinamide (pa) and praseodymium bromide-na are reported. The structures of CaCl2·(C6H6N2O)2·2H2O (Ca-na), CaCl2·(C6H6N2O)2·4H2O (Ca-ina), CaCl2·(C6H6N2O)2·5H2O (Ca-pa) and PrBr3·(C6H6N2O)2·6H2O (PrBr-na) in the solid state have been characterized by X-ray single crystal diffraction, FTIR, FIR, THz and Raman spectroscopies. Carbonyl oxygen of nicotinamide is coordinated to Ca(2+), but it is O-monodentate (carbonyl oxygen) and N,O-bidentate ligand (pyridyl nitrogen and carbonyl oxygen) for Pr(3+) to form a chain structure in PrBr-na. For isonicotinamide, only carbonyl oxygen atom is coordinated to Ca(2+). Pyridyl nitrogen and carbonyl oxygen of picolinamide are coordinated to Ca(2+) to form a five-membered ring structure. The crystal structure and spectroscopic results indicate the differences of the coordination of Ca and Pr ions, the changes of hydrogen bonds and conformation of the ligands induced by complexation. Unlike transition metal ions, Sr(2+) or lanthanide ions, Ca(2+) is inclined to coordinate to carbonyl oxygen atoms of the ligands.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China; Department of Chemistry, Renmin University of China, Beijing 100872, China.
authors.forename: Junhui
authors.initials: J
authors.lastname: Xue
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China. Electronic address: yanglm@pku.edu.cn.
authors.forename: Limin
authors.initials: L
authors.lastname: Yang
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. Electronic address: xyz@pku.edu.cn.
authors.forename: Yizhuang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Physics, Capital Normal University, Beijing 100037, China.
authors.forename: Guozhong
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Department of Physics, Capital Normal University, Beijing 100037, China.
authors.forename: Gaohui
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Physics, Capital Normal University, Beijing 100037, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Bu
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Kexin
authors.initials: K
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Jia'er
authors.initials: J
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
authors.forename: Jinguang
authors.initials: J
authors.lastname: Wu
mesh_terms: D000577:Amides / Q000737:chemistry; D001965:Bromides / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D002122:Calcium Chloride / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D006860:Hydrogen Bonding; D007477:Ions; D008024:Ligands; D008670:Metals / Q000737:chemistry; D009536:Niacinamide / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010848:Picolinic Acids / Q000737:chemistry*; D011221:Praseodymium / Q000737:chemistry*; D013053:Spectrophotometry; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D000577:Amides; D001965:Bromides; D007477:Ions; D008024:Ligands; D008670:Metals; D010848:Picolinic Acids; D009536:Niacinamide; C027681:isonicotinamide; D002244:Carbon; C003142:picolinamide; D002122:Calcium Chloride; D009584:Nitrogen; D011221:Praseodymium; D010100:Oxygen; D002118:Calcium
keywords: Complexation; Crystal structure; FT-IR; Isonicotinamide; Nicotinamide; Picolinamide