Preparation and characterization of the first coordination compounds of tetrazol-2-ylacetic acid

Novel tetrazole PtII and PdII complexes with enhanced water solubility: synthesis, structural characterization and evaluation of antiproliferative activity

Novel platinum(II) and palladium(II) chlorido complexes with tetrazole derivatives 1-(2-hydroxyethyl)tetrazole (het) and 1-[tris(hydroxymethyl)methyl]tetrazole (thm), viz. cis-[Pt(het)2Cl2], trans-[Pt(het)2Cl2], trans-[Pt(thm)2Cl2], trans-[Pd(het)2Cl2], and trans-[Pd(thm)2Cl2], were synthesized. The compounds were characterized by elemental and high-resolution electrospray ionization (HRESI) mass spectrometry, high-performance liquid chromatography (HPLC), 1H, 13C and 195Pt nuclear magnetic resonance (NMR) spectroscopy, thermal analyses, and Infrared (IR) spectroscopy. Molecular and crystal structures of trans-[PdL2Cl2] and trans-[PtL2Cl2] (L = het, thm) were established by single-crystal X-ray analysis. The complex cis-[Pt(het)2Cl2] was found to undergo cis–to–trans isomerization upon heating in acetonitrile solution and in the solid state. The synthesized complexes show rather high water solubility lying in the range of 2–10 mg/L.

An X-ray powder study of the structure and microstructure of trans-dichloridobis(1,5-diamino-1H-tetrazole-κN4)palladium(II)

The crystal structure of the coordination compound [PdCl2(CH4N6)2], trans-dichloridobis(1,5-diamino-1H-tetrazole-κN4)palladium(II), has been determined from X-ray powder diffraction data collected at room temperature. The structure has been solved by direct methods and refined using Rietveld analysis. The complex crystallizes in the monoclinic space group P21/c, with Z=2. The unit cell dimensions are a=5.73491(4), b=11.94450(4), c=8.61685(4)Å, and β=99.6367(6)° with cell volume V=581.930(5)Å3. A slightly distorted square-planar coordination geometry is formed around the Pd atom by two Cl atoms and two tetrazole ring N atoms of two 1,5-diamino-1H-tetrazole ligands, which are in a trans configuration. In the complex molecule, the planes of the tetrazole rings are inclined at 53.7(3)° with respect to the coordination plane. Intermolecular hydrogen bonds of the amino groups N—H···Cl and N—H···Nring are responsible for formation of a three-dimensional supramolecular network. The powder pattern of the compound was strongly affected by the anisotropic line broadening. The width of the Bragg peaks was interpreted by a phenomenological microstructural approach in terms of anisotropic strain effect to complete the Rietveld refinement.

Poly[[bis-[3-(1H-tetra-zol-1-yl)propanoic acid-κN(4)]cadmium]-di-μ-thio-cyanato-κ(2)N:S;κ(2)S:N]

In the title compound, [Cd(NCS)(2)(C(4)H(6)N(4)O(2))(2)](n), the Cd(II) cation is located on an inversion center and is coordinated by two N and two S atoms from four SCN(-) anions and two N atoms from two 3-(1H-tetra-zol-1-yl)propanoic acid (Htzp) ligands in a distorted octa-hedral geometry. The SCN(-) anions bridge the Cd(II) cations into a layer structure parallel to (100). A weak intra-molecular C-H⋯N inter-action occurs. The layers are further assembled into a three-dimensional supra-molecular structure via classical O-H⋯O hydrogen bonds.