Synthesis and Crystal Structure of Hexakis(imidazole) nickel (II) O,O′-diphenyldithiophosphate [Ni(Im)6](Ph2O2PS2)2
The crystal and molecular structures of [Ni(Im)6](dtp)2 (Im = imidazole, dtp = O,O′-diphenyldithiophosphate) have been determined by X-ray crystallography. It crystallizes in the triclinic system, space group Pī, with cell parameters a = 9.375 (2), b = 12.324(3), c = 13.285(3) Å, α = 107.86(3), β = 102.28(3), γ = 109.24(3), and Z = 1. The crystal structure of the title compound is built up of discrete monomeric molecules of [Ni(Im)6](dtp)2. The nickel (II) ion is hexacoordinated by six imidazole molecules and the coordination environment of Ni (II) is of octahedral geometry. In the solid state, a network of N-H∙∙∙S intermolecular hydrogen bonds connect the Ni(Im)6 moieties and O,O′-diphenyl- dithiophosphate molecules, forming a three-dimensional structure.
X-ray structures of heteroleptic zinc(II) complexes involving combinations of O,O′-dialkyldithiophosphato and bidentate N-donor ligands
Abstract The detailed X-ray structural elucidation of reaction products of a zinc(II) salt with O,O′-dialkyldithiophosphate and nitrogen-containing heterocycles (N–N=1,10-phenanthroline (phen) or 2,2′-bipyridine (bpy)) has been performed. Surprisingly, together with [Zn(S2 P(OR)2)2(N–N)] compounds, also ionic-type complexes having the formula of [Zn(N–N)3](S2 P(OR)2)2 have been obtained using the same molar ratios of the reactants. The prepared complexes have been characterized by elemental analysis and single-crystal X-ray analysis. The crystallographic analysis showed that the bond lengths and bite angles of the prepared complexes are in good agreement with those of similar compounds. The crystal packing of described complexes is formed via π–π stacking interactions and/or C–H···S non-covalent contacts.
Electrochemical detection of copper(II) at a gold electrode modified with a self-assembled monolayer of penicillamine
A penicillamine (PCA) self-assembled monolayer (SAM) was prepared on a gold electrode. It has been found that the modified electrode exhibited a selective response to copper ions. As demonstrated by cyclic voltammetric experiments, the SAM-based electrode showed an attractive ability to preconcentrate efficiently traces of copper(II) from solutions. Under optimum conditions, the anodic peak current was proportional to the concentration of Cu(II) in the range from 8.0 × 10−7 to 1.0 × 10−4 M with a detection limit of 4.0 × 10−7 M. Moreover, this modified gold electrode is also characterized by excellent repeatability, showing a relative standard deviation of 3.2% for nine successive measurements of 1.0 × 10−5 M Cu(II). The PCA/Au SAM gold electrode was used for the determination of Cu(II) in a tap water sample and the results showed a good agreement with the data obtained by atomic emission spectrometry.