Synthesis and Crystal Structures of Two Complexes with Carboxylic Derivatives of Nitrogen-containing Heterocycle Ligands

Abstract  

Two new complexes [Zn(pcn)₂(H₂O)₂] (1) and [Cd(inic)₂(H₂O)₄] (2) (pcn = 2-pyrazinecarboxylate, inic = isonicotinic acid) were synthesized by the hydrothermal reaction and characterized by single crystal X-ray diffraction, elemental analysis, IR spectrum and UV spectrum. In complex 1, the Zn(II) central ion is six-coordinated by two oxygen atoms and two nitrogen atoms from pcn ligands and two oxygen atoms from two coordinated water molecules. In complex 2, the Cd(II) central ion is six-coordinated by two nitrogen atoms from isonicotinate ligands and four oxygen atoms from the coordinated water molecules. Both complexes are mononuclear but hydrogen bonds enrich the structural construction. The visible spectra of the complexes between 200 and 300 nm are assigned to intraligand (IL) π–π* transitions of the pyridyl or pyrazine ligands.     

Synthesis and Crystal Structures of Two Metal Urea Nitrates

Abstract  Cu(urea)₂(H₂O)₃(NO₃).(urea)(NO₃) (1) and Zn(urea)₄(H₂O)₂·2(NO₃) (2) have been obtained from the corresponding metal nitrates and urea in warm aqueous solvent. These are unusual examples of complexes of transition metals coordinated only by urea and water. 1 crystallizes in the monoclinic space group P2₁/m with unit cell parameters a = 9.489(3), b = 13.059(3), c = 7.103(2) ? and β = 100.28(3)°. The copper ion occupies a 2e position on a mirror plane and displays four short Cu–O bonds (2 × Cu–OH₂ and 2 × Cu–O=C(NH₂)₂) and two much longer contacts (Cu–OH₂ and Cu–ONO₂) consistent with a Jahn–Teller distortion. Between the cations are located unbound urea and nitrate. 2 crystallizes in the monoclinic space group P2₁/n with a = 6.4239(11), b = 17.690(4), c = 7.5877(13) ? and β = 91.138(14)°. The zinc ion resides on the 2a position, an inversion centre, and displays pseudo–octahedral coordination geometry. It is coordinated by four equatorial urea and two axial water molecules. The four molecules of urea are nearly planar and form N–H···O intramolecular hydrogen bonds. Unbound charge-balancing nitrate is also present. In each compound there is extensive intermolecular hydrogen bonding between the water, urea, and nitrate present. Pyrolysis of the compounds under 10% hydrogen in nitrogen at 300 °C was found to yield metallic copper in the case of 1 and zinc oxide for 2. Graphical Abstract  The structures of two new metal urea nitrates have been determined at low temperature      

The Molecular and Crystal Structures of 2-Iodokojic Acid: Experimental and Theoretical Determination

Abstract  

The crystal structure of 2-iodokojic acid, (2-jodo-3-hydroxy-6-hydroxymethyl)-4-H-pyran-4-one) (C₆H₅IO₄, Mr = 268.00) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the orthorhombic crystal system with space group Pc2₁b and unit cell parameters: a = 4.0830(2), b = 15.3510(5), c = 23.517(1) ? and Z = 8. The final reliability index is 0.0288 for 2,584 observed reflections. The two molecules of iodokojic acid, slightly differing in their molecular structure, are localized in independent part of unit cell. The crystal packing is stabilized by O–H···O hydrogen bonds and I···O intermolecular interactions. The molecular structure of iodokojic acid determined experimentally little differs from that obtained by the applied theoretical (Hartree–Fock and four versions of DFT) methods, the differences should not be taken as a measure of the reliability of the theoretical methods.     

两个晶态异质同构配合物荧光材料的合成、结构及性质

在水中采用蒸发溶剂的方法,合成了两个异质同构的单核配合物[M(phen)2(H2O)2]·2SIPH2·2H2O (M=Zn,Co),SIPH2=间苯二甲酸-5-磺酸根阴离子,phen=1,10-邻菲罗啉).在两个配合物结构单元中,中心离子与两个1,10-邻菲罗啉和两个水分子配位,形成[M(phen)2(H2O)2]2+阳离子.两个未配位的水分子与[M(phen)2(H2O)2]2+阳离子,SIPH2-阴离子通过氢键相互连接形成三维的网状结构.SIPH2-阴离子起到平衡电荷的作用.室温下两个配合物均具有荧光发射峰,其发射峰分别在460 nm和439 nm.与配体相比,均发生明显的红移.荧光寿命分别为1.7638 ms和1.6356 ms.     

两个单核配合物晶态荧光材料的合成、晶体结构及性质

在水中采用蒸发溶剂的方法,合成了两个晶态单核配合物[Co(phen)3]·2H2SPA·0.5HSPA·10H2O(1)和[Ni(phen)2(H2O)2]·H2SPA·0.5HSPA·3H2O(2)(H2SPA'=间苯二甲酸-5-磺酸根阴离子,phen=1,10-邻菲罗啉).在配合物1中,中心离子与三个1,10-邻菲罗啉配位,形成[Co(phen)3]2+.未配位的水分子与阴离子H2SPA-和HSPA2-通过氢键相互连接形成三维的网状结构.在配合物2中,中心离子与两个1,10-邻菲罗啉分子和两个水分子配位,构成阳离子[Ni (phen)2(H2O)2]2+.阳离子[Ni (phen)2(H2O)2]2+与自由的阴离子H2SPA-、阴离子HSPA-和未配位的水分子通过氢键连接形成三维网状结构.室温下两个配合物均具有荧光发射峰,其发射峰分别在460 nm和439 nm.与配体相比,均发生明显的红移.荧光寿命分别为1.1244 ns和1.4882 ns.     

Synthesis, Crystal Structures and Molecular Packing of a Series of Pyrazolo-Benzothiazine Hybrid Derivatives

Abstract  

The crystal structures of four derivatives of pyrazolo[4,3-c][1,2]benzothiazine-2,4-dihydro-3,4-dimethyl-,5,5-dioxide containing benzothiazine dioxide and pyrazolo fused rings that have been synthesized were determined. (C₁₁ H₁₁ N₃ O₂ S): Mr = 249.29, monoclinic, P2₁/c, a = 8.3070(3), b = 13.6331(5), c = 10.1661(3) ?, β = 106.924(2)°, V = 1101.45(7) ?^3, Z = 4. (C₁₂ H₁₃ N₃ O₂ S): Mr = 263.31, monoclinic, P2₁/n, a = 9.729(3), b = 11.224(4), c = 11.436(3) ?, β = 98.85(2)°, V = 1233.9(7) ?³, Z = 4. (C₁₄ H₁₅ N₃ O₄ S): Mr = 321.35, monoclinic, P2₁/c, a = 9.2534(3), b = 19.3920(7), c = 7.9489(2) ?, β = 95.323(2)°, V = 1420.21(8) ?^3, Z = 4. (C₁₄ H₁₅ N₃ O₃ S): Mr = 305.35, monoclinic, P2₁ /c, a = 13.816(7), b = 7.464(3), c = 14.674(8) ?, β = 109.05(3)°, V = 1430.3(12) ?³, Z = 4. The heterocyclic thiazine rings adopt half-chair conformations, and the mean-planes of the phenyl and pyrazolo rings lie between 10.43(11) and 15.93(16)° with respect to each other. In each case, the geometry about thiazine N-atom is trigonal pyramidal and only the first compound containing a donor N-atom shows classical hydrogen bonds. However, non-classical H-bonding of the type C–H···O is observed in all structures.