Fast chromium determination in pharmaceutical tablets by using electrochemical sensors: Preparation and comparison.

In the present paper, three electrodes were prepared with the aim of detecting chromium (III) in pharmaceutical tablets and comparing their capabilities and efficiency. At first, N-(pyridine-2-ylcarbamothioyl) benzamide (NP2YCTB) was synthesized and characterized by H NMR, FTIR, and C NMR spectroscopy methods. Then, it is used as a sensing material to prepare three types of chromium potentiometry sensors including solid-state electrodes (SSE), coated wire electrodes (CWE) as asymmetric electrodes, and liquid membrane electrodes (LME) as symmetric electrodes.

Chromium measurement in pharmaceutical samples: a comparative study of three new membrane electrodes with different electron-ion exchangers.

The present study deals with synthesis of -(thiazol-2-ylcarbamothioyl) benzamide. It was utilized as a neutral ionophore for designing three types of chromium(III) sensors including coated wire ion selective electrodes (CW-ISEs), ion selective electrodes with liquid internal electrolyte (LIE-ISEs), and solid-state ion selective electrodes (SS-ISEs). UV-visible spectrophotometry was used to confirm the affinity of -(thiazol-2-ylcarbamothioyl) benzamide to chromium(III).

Dibromido(2,3,5,6-tetra-2-pyridyl-pyrazine-κN,N,N)zinc(II).

In the title compound, [ZnBr(2)(C(24)H(16)N(6))], the Zn(II) ion is coordinated by the N,N',N''-tridentate 2,3,5,6-tetra-2-pyridyl-pyrazine ligand and two bromide ions, generating a distorted ZnN(3)Br(2) trigonal-bipyramidal geometry for the metal ion, with both bromide ions in equatorial sites. The dihedral angles between the pyrazine ring and the coordinated pyridine rings are 13.3 (2) and 24.

Dibromido(6-methyl-2,2'-bipyridine-κN,N')zinc(II).

In the title compound, [ZnBr(2)(C(11)H(10)N(2))], the Zn(II) atom is four-coordinated in a distorted tetra-hedral configuration by two N atoms from a 6-methyl-2,2'-bipyridine ligand and two terminal Br atoms. Weak inter-molecular C-H⋯Br hydrogen bonds and π-π stacking inter-actions between the pyridine rings [centroid-centroid distances = 3.763 (5) and 3.

catena-Poly[[(5,5'-dimethyl-2,2'-bi-pyridine-κN,N')cadmium(II)]-di-μ-iodido].

In the title coordination polymer, [CdI(2)(C(12)H(12)N(2))](n), the Cd(2+) ion lies on a twofold rotation axis: it is six-coordinated in a distorted cis-CdN(2)I(4) octa-hedral geometry by two N atoms from a chelating 5,5'-dimethyl-2,2'-bipyridine ligands and four bridging iodide anions. The bridging function of the iodide ions leads to a chain structure propagating in [001].

(4,4'-Dimethyl-2,2'-bipyridine-κN,N')(dimethyl sulfoxide-κO)diiodidocadmium(II).

In the title compound, [CdI(2)(C(12)H(12)N(2))(C(2)H(6)OS)], the Cd(II) cation is coordinated by two N atoms from a dimethyl-bipyridine ligand, one O atom from a dimethyl sulfoxide mol-ecule and two I(-) anions in a distorted trigonal-bipyramidal geometry. Intra-molecular C-H⋯O hydrogen bonding and inter-molecular π-π stacking between parallel pyridine rings [centroid-centroid distance = 3.658 (3) Å] are present in the crystal structure.

Dichlorido(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline-κN,N')mercury(II) acetonitrile hemisolvate.

The asymmetric unit of the title compound, [HgCl(2)(C(26)H(20)N(2))]·0.5CH(3)CN, contains two crystallographic-ally independent [HgCl(2)(C(26)H(20)N(2))] mol-ecules and one acetonitrile solvent mol-ecule. The Hg(II) atoms are four-coordin-ated in distorted tetra-hedral configurations by two N atoms from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ligands and two Cl atoms.

(6,6'-Dimethyl-2,2'-bipyridine-κN,N')diiodidozinc(II).

The complete mol-ecule of the title compound, [ZnI(2)(C(12)H(12)N(2))], is generated by crystallograpic twofold symmetry, with the Zn(II) atom lying on the rotation axis. The Zn(II) atom is coordinated by the N,N-bidentate 6,6'-dimethyl-2,2'-bipyridine ligand and two iodide ions, resulting in a distorted ZnN(2)I(2) tetra-hedral geometry for the metal. In the crystal, there are weak π-π contacts between the pyridine rings [centroid-centroid distance = 3.

Dichlorido(6,6'-dimethyl-2,2'-bipyridine-κN,N')zinc(II).

In the title compound, [ZnCl(2)(C(12)H(12)N(2))], the complete mol-ecule is generated by crystallographic mirror symmetry, with the Zn atom and both chloride ions lying on the reflecting plane, yielding a distorted ZnN(2)Cl(2) tetra-hedral coordination for the metal ion. In the crystal, there are π-π contacts between the pyridine rings [centroid-centroid distance = 3.7857 (17) Å].

Tetra-kis(6-methyl-2,2'-bipyridine)-1κN,N';2κN,N';3κN,N';4κN,N'-tetra-μ-nitrato-1:2κO:O';2:3κO:O',O'';2:3κO,O':O'';3:4κO:O'-tetra-nitrato-1κO,O';4κO,O'-tetra-lead(II).

In the tetranuclear centrosymmetric title compound, [Pb(4)(NO(3))(8)(C(11)H(10)N(2))(4)], irregular PbN(2)O(5) and PbN(2)O(4) coordination polyhedra occur. The hepta-coordinated lead(II) ion is bonded to two bidentate and one monodentate nitrate ion and one bidentate 6-methyl-2,2'-bipyridine (mbpy) ligand. The six-coordinate lead(II) ion is bonded to one bidentate and two monodentate nitrate anions and one mbpy ligand.

Dibromido(di-2-pyridylamine-κN,N')mercury(II).

In the mol-ecule of the title compound, [HgBr(2)(C(10)H(9)N(3))], the Hg(II) atom is four-coordinated in a distorted tetra-hedral configuration by two N atoms from the chelating di-2-pyridylamine ligand and by two Br atoms. In the crystal structure, inter-molecular N-H⋯Br hydrogen bonds link the mol-ecules into centrosymmetric dimers. There are π-π contacts between the pyridine rings [centroid-centroid distances = 3.

Dichlorido(6-methyl-2,2'-bipyridine-κN,N')mercury(II).

In the mol-ecule of the title compound, [HgCl(2)(C(11)H(10)N(2))], the Hg(II) atom is four-coordinated in a distorted tetra-hedral configuration by two N atoms from a 6-methyl-2,2'-bipyridine ligand and two Cl atoms. There is a π-π contact between the pyridine rings [centroid-centroid distance = 3.9758 (5) Å].

Di-μ-bromido-bis-[bromido(4,4'-dimethyl-2,2'-bipyridine-κN,N')mercury(II)].

The asymmetric unit of the title compound, [Hg(2)Br(4)(C(12)H(12)N(2))(2)], contains one half-mol-ecule. The Hg(II) atom is five-coordinated in a trigonal-bipyramidal configuration by two N atoms from the chelating 4,4'-dimethyl-2,2'-bipyridine ligand, two bridging Br and one terminal Br atom, leading to a centrosymmetric dimeric mol-ecule. There is a π-π contact between the pyridine rings [centroid-to-centroid distance = 3.

Trichlorido(5,5'-dimethyl-2,2'-bipyridine-κN,N')(methanol-κO)indium(III).

In the mol-ecule of the title compound, [InCl(3)(C(12)H(12)N(2))(CH(4)O)], the In(III) atom is six-coordinated in a distorted octa-hedral configuration by two N atoms from the chelating 5,5'-dimethyl-2,2'-bipyridine ligand, one O atom from a methanol molecule and three Cl atoms. In the crystal structure, inter-molecular O-H⋯Cl hydrogen bonds link the mol-ecules into chains parallel to [001].

Trichlorido(4,4'-dimethyl-2,2'-bipyridine-κN,N')(dimethyl sulfoxide-κO)indium(III).

In the mol-ecule of the title compound, [InCl(3)(C(12)H(12)N(2))(C(2)H(6)OS)], the In(III) atom is six-coordinated in a distorted octa-hedral configuration by two N atoms from the chelating 4,4'-dimethyl-2,2'-bipyridine ligand, one O atom from dimethyl sulfoxide and three Cl atoms. In the crystal structure, inter-molecular C-H⋯Cl hydrogen bonds link the mol-ecules into centrosymmetric dimers.

Bis(2,4,6-trimethyl-pyridinium) hexa-chloridoplatinate(IV).

The asymmetric unit of the title compound, (C(8)H(12)N)(2)[PtCl(6)], contains one independent protonated 2,4,6-trimethyl-pyridinium cation and one half of a centrosymmetric [PtCl(6)](2-) anion. The Pt ion has an almost ideal octa-hedral coordination. In the crystal structure, intra-molecular N-H⋯Cl and inter-molecular C-H⋯Cl hydrogen bonds result in the formation of a supra-molecular structure.

Dichlorido(6-methyl-2,2'-bipyridine-κN,N')zinc(II).

In the mol-ecule of the title compound, [ZnCl(2)(C(11)H(10)N(2))], the Zn(II) atom is four-coordinated in a distorted tetra-hedral configuration by two N atoms from the 6-methyl-2,2'-bipyridine ligand and by two Cl atoms. There are π-π contacts between the pyridine ring and the five-membered ring, and also between the pyridine rings, [centroid-centroid distances = 3.685 (3) and 3.

catena-Poly[[(5,5'-dimethyl- 2,2'-bipyridine-κN,N')cadmium(II)]-di-μ-chlorido].

The asymmetric unit of the title compound, [CdCl(2)(C(12)H(12)N(2))](n), contains one half-mol-ecule; a twofold rotation axis passes through the Cd atom. The Cd(II) atom is six-coordinated in a distorted octa-hedral configuration by two N atoms from 2,2'-bipyridine-5,5'-dimethyl and four bridging Cl atoms. The bridging function of the chloro atoms leads to a one-dimensional chain structure.