Crystal and molecular structure of bis(creatinite)silver(I) perchlorate dihydrate

Coordination properties of the bioligands creatinine and creatine in various reaction media

Abstract: Data on the ability of the important bioligands creatinine and creatine to form various types of complexes with different metal ions are summarized. The crucial role of the nature of the reaction medium in complex formation with these ligands is emphasized. The conditions for obtaining paramagnetic oligomeric platinum complexes of the “platinum blue” type (resulting from multistep redox and coordination processes) are presented.

Gold Nanoparticle-Based Colorimetric Recognition of Creatinine with Good Selectivity and Sensitivity

Abstract: A gold nanoparticle-based colorimetric sensor for the determination of creatinine was developed as an important index for early diagnosis of kidney function and corresponding renal diseases. Because of the unique synergistic coordination capability of adenosine and creatinine with Ag+ on a particle surface, our system exhibits an excellent selectivity to creatinine among various ions and biomolecules. There are good linear relationships of absorption changes (A630 nm/520 nm) over creatinine concentrations, so both colorimetric qualitative detection by the naked eye and quantitative determination by UV–vis spectrometer could be realized with an excellent limit of detection compared with that of other methods. Finally, by testing creatinine in practical samples, such as urine mimic and bovine serum, good recoveries were obtained with proper relative standard deviations.

Silver coordination and organometallic compounds: classification and analysis of crystallographic and structural data

Abstract: This review summarizes the data for almost six hundred silver coordination and organometallic compounds, with the silver atom occurring in oxidation states of +1, +2, and two examples of +3 in a square-planar environment. The +2 oxidation state is found in digonal, square-planar, tetrahedral and hexa-coordinated environments. The +1 oxidation state is by far the most common in various geometries from two to seven. The nuclearity range from mono- to polynuclear utilizing a variety of ligand types. There are several examples of distortion isomerism, and a few examples of polymerization isomerism. Correlations between bond lengths, bond angles, ligating atom radius and silver oxidation state are discussed.

Monomeric Pt(II) and Pd(II) complexes with Creatinine. Crystal structure of tetrakis-(Creatinine) platinum(II) diperchlorate

Abstract: Pt(II) and Pd(II) complexes with creatinine, C3H2N2(O)(CH3)NH2, were synthesized. Potentiometric and IR spectroscopic analyses were carried out. A model for the coordination of the ligands to the central atoms was confirmed by X-ray structural investigation of Pt(creat)4(ClO4)2. The compound [Pt(C4H7N3O)(ClO4)2] crystallizes in the monoclinic crystal system, space group C2/c, a = 15.748(5), b = 15.763(7), c = 24.843(8) A, β = 106.84(4)°, V = 5902 A3, Z = 8. The refinement of the structure by the least-squares method gave R = 0.051 and Rw = 0.054 for 1527 observed reflections with I > 2σ(I). The structure consists of Pt(creat)42+ complex cations, possessing approximate D2 symmetry and rotationally disordered perchlorate anions. The Pt atom is square-planarly coordinated by the endocyclic N atoms of four creatinine ligands. The PtN bond lengths range from 2.00(2) to 2.03(1) A and the NPtN angles from 88.4(9) to 91.8(8)°. The ligands are almost planar and tilted towards the PtN4-plane by 82.1(8)–93.5(9)°.

The dissolution of silver–sodium–calcium–phosphate glasses for the control of urinary tract infections

Abstract: Cast tubes of silver–sodium–calcium–phosphate controlled release glasses have been developed for the delivery of a constant concentration of silver ion in aqueous flow systems. In the solid glasses calcium ions are preferentially located at the ends of polyphosphate chains and randomly at middle-group sites. The polyphosphate anions that persist after dissolution have been analyzed by two-dimensional NMR methods; a range of linear ions can be detected but the predominant species is cyclo -hexaphosphate. With water as flow medium the concentration of silver in the effluent depends on the glass composition. When the flow medium is simulated urine, which contains, among other constituents, chloride, urea and creatinine, the concentration of silver is controlled by the equilibrium between solid silver chloride and the bis(creatinine)silver cation.

Coherent X‐Ray Scattering for the Hydrogen Atom in the Hydrogen Molecule

Abstract: The x‐ray form factors for a bonded hydrogen in the hydrogen molecule have been calculated for a spherical approximation to the bonded atom. These factors may be better suited for the least‐squares refinement of x‐ray diffraction data from organic molecular crystals than those for the isolated hydrogen atom. It has been shown that within the spherical approximation for the bonded hydrogens in H2, a least‐squares refinement of the atomic positions will result in a bond length (Re value) short of neutron diffraction or spectroscopic values. The spherical atoms are optimally positioned 0.07 A off each proton into the bond. A nonspherical density for the bonded hydrogen atom in the hydrogen molecule has also been defined and the corresponding complex scattering factors have been calculated. The electronic density for the hydrogen molecule in these calculations was based on a modified form of the Kolos—Roothaan wavefunction for H2. Scattering calculations were made tractable by expansion of a plane wave in spheroidal wavefunctions.

Crystal and molecular structure of creatininium tetrachlorocuprate(II)

Abstract: Preparation, crystal and molecular structure of creatininium tetrachlorocuprate(II) is described. The structure was solved by X-ray diffraction studies and was refined by least-squares methods to R = 0.041 for 1344 reflections. The compound is monoclinic, space group, P21/c. The unit cell parameters are a = 8.080(3), b = 7.831(2), c = 13.922(3) A, β = 113.77(2)°, V = 806.2 A3, dc = 1.786, dm = 1.77(1) g cm−3, Z = 2. The [CuCl4]2− ion is centrosymmetric and the copper atom is surrounded by four Cl atoms (CuCl1 2.233(1), CuCl2 2.268(1)) in a square planar arrangement. The creatininium cation is almost planar and each cation is linked to [CuCl4]2− units through hydrogen bonding involving the amino and imino nitrogen atoms.

The crystal and molecular structure of tris(thiourea)silver(I) perchlorate

Abstract: Tris(thiourea)silver(I) perchlorate, Ag[SC(NH2)2]3ClO4, is monoclinic with cell parameters a = 19.537(8), b = 13.436(6), c = 10.791(5) A, β = 103.57(5)°. The space group is C2/c with Z = 8, dc = 2.102 g. cm−3 and dm = 2.090 g.cm−3. The crystal structure was determined from three-dimensional diffractometer data and refined by least-squares methods with anisotropic thermal parameters to a conventional R factor of 0.048 for 2202 observed reflections. The structure is ionic and consists of binuclear complexes (Ag2[SC(NH2)2]6)2+ with C2 symmetry and perchlorate anions. The sulphur atoms of four thiourea molecules form a distorted coordination tetrahedron (SAgS angles range from 100.5(1) to 115.9 (1)°) around each Ag. Two of the six sulphur atoms of the binuclear complex cation act as bridging ligands in a four-membered AgSAgS ring (bridge bond lengths 2.663(2) and 2.684(2) A), the remaining four are terminal (AgS bond lengths 2.524(2) AND 2.570 (2) A). The bond angle AgSAg is 64.3(1), the Ag… Ag distance in the binuclear complex is 2.845(1) A. The bonding of the complex cation is different from the corresponding copper(I) complex. The orientation of the thiourea molecules suggests use of electron pairs of pπ sulphur-carbon MO's in the terminal as well as (together with sulphur sp2 orbitals) in the bridge AgS bonds.