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Kinetic Study of the Hydrolysis of BNPP by the Cerium(III) Complex

5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetraazacyclotetradecane (L) was synthesized and characterized. The kinetics of hydrolysis of bis(p-nitrophenyl)phosphate (BNPP) in the catalytic system containing macrocyclic ligand and cerium(III) was investigated. This catalytic system show high catalytic activity and better reproducibility and stability than other similar systems in the range of pH of around 5.6–7.2. The stoichiometry and spectral analysis showed that the real active species is the macrocyclic complex of cerium(III). Based on the analytical results of the specific absorption spectra, an intramolecular nucleophilic substitution mechanism for the catalytic hydrolysis of BNPP is proposed, a correlative kinetic mathematical model is established, and the corresponding thermodynamic and kinetic constants are calculated.

A 2D Cd(II)-MOF as a multifunctional luminescencent sensor for nitroaromatics, iron(III) and chromate ions

Abstract A Cd(II)-MOF, {[Cd(L)(4,4′-bipy)]·H2O·DMF}n (1) (L = nicotinic acid (2,4-dihydroxybenzylidene)-hydrazide and 4,4′-bipy = 4,4′-bipyridine), has been synthesized and characterized by microanalyses, FTIR, TGA, and single-crystal X-ray diffraction. Additionally, powder X-ray diffraction was performed to check the phase purity of the synthesized compound. Single-crystal X-ray diffraction reveals that 1 has a 2D grid network. Photoluminescent sensing of nitrobenzene, Fe(III) and CrO42− ions indicates that 1 could be a candidate for developing selective luminescent sensors for these species. Theoretical calculations have been performed to gain insight into the possible mechanism of quenching effect in emission on addition of nitrobenzene in 1 which supports the mechanism operating through ground state charge transfer between 1 and nitrobenzene.

An Extremely Stable 2D Zinc(II) Coordination Polymer Exhibiting High Sensing Ability and Photocatalytic Degradation Activities of Dyes

A new 2D Zn(II) metal-organic framework of {[Zn(L)(4,4′-bipy)·CH3CN]n (1) has been developed using 5-aminoisophthalic acid (H2L) and 4,4′-bipyridine ligands. The single crystal X-ray diffraction study indicates that 1 is composed of infinite 2D layer. The chemically stable 1 behaves as a highly selective and sensitive fluorescence chemosensor for detection of Hg2+ and 4-nitrotoluene (4-NT) analyte. Furthermore, the photocatalytic properties of 1 for degradation of the methyl violet (MV) and Rhodamine B (RhB) have been explored.

Catalytic mechanism and activity of a nitrogen heterocycle lanthanum(III) complex in the hydrolysis of bis(4-nitrophenyl) phosphate ester

The system made up of a nitrogen heterocycle ligand and lanthanum(III) ion was used in the catalytic hydrolysis of bis(4-nitrophenyl) phosphate ester (BNPP). This catalytic system showed higher catalytic activity in this hydrolysis and better reproducibility and stability than other similar lanthanum(III) ion systems. The rate of the catalytic hydrolysis was about 108-fold faster than that of its spontaneous hydrolysis under the same conditions. Compared with previous Cu(II) or Ni(II) complexes containing the same ligand in water, the activity of the macrocyclic La(III) complexe is increased ca 104-fold. The experimental evidence showed that the mon-hydroxy complex made of the nitrogen heterocycle ligand and lanthanum(III) ion is the active species as catalyst in the catalytic hydrolysis of BNPP.

Bis(4'-hy-droxy-biphenyl-4-carboxyl-ato-κO)(1,10-phenanthroline-κN,N')zinc.

In the title compound, [Zn(C13H9O3)2(C12H8N2)], the ZnII atom is located on a twofold rotation axis and has a distorted tetrahedral coordination with two N atoms from the phenanthroline ligand arranged around the twofold axis and two O atoms from two symmetry-related 4′-hydroxybiphenyl-4-carboxylate ligands. The molecules are linked by O—H⋯O hydrogen bonds, forming a chain developing parallel to [101].

Kinetic Study on p-Nitrophenyl Picolinate Hydrolysis Promoted by the Complex Bis(O,O′-di(2-Benzyl)Dithiophosphato)Nickel(II)

The complex Ni[S2P(OCH2Ph)2]2 (MR) was synthesised and characterised by elemental analysis, IR spectroscopy and 1H NMR spectroscopy. The hydrolysis of p-nitrophenyl picolinate (PNPP) as promoted by this complex was investigated by the UV-vis method, the results showing that MR acts as a very efficient catalyst. The specific absorption spectra of the hydrolytic reaction systems indicated that the key intermediate, made up of PNPP and MR was formed during reaction. Based on these spectra, a mechanism for the catalytic hydrolysis of PNPP has been proposed and a kinetic mathematical model established.

(5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetra­aza­cyclo­tetra­deca-4,11-diene)nickel(II) bis­[O,O′-bis­(4-tert-butyl­phen­yl) dithio­phosphate]

The title salt, [Ni(C16H32N4)](C20H26O2PS2)2, comprises a centrosymmetric [Ni(Me6[14]dieneN4)]2+ dication (Me6[14]dieneN4 is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) and two O,O′-bis(4-tert-butylphenyl) dithiophosphate anions. The NiII ion lies on an inversion centre and displays a slightly distorted NiN4 square-planar chelation arrangement with four N atoms from the Me6[14]dieneN4 macrocycle. Two S atoms from symmetry-related anions are located in pseudo-axial positions with respect to the NiII ion, with Ni⋯S distances of 3.2991 (7) Å. Intermolecular N—H⋯S and C—H⋯S hydrogen bonds link the complex cation and pair of anions into a 1:2 type salt.

(meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetra­azacyclo­tetra­deca­ne)copper(II) bis­(O,S-dibenzyl dithio­phosphate)

In the crystal structure of the title compound, [Cu(C16H36N4)](C14H14O2PS2)2, the CuII atom is located on an inversion center and is chelated by four N atoms of the macrocyclic meso-5,5,7,12,12,14- hexamethyl-1,4,8,11-tetraazacyclotetradecane ligand in a square-planar geometry, with Cu—N distances of 2.013 (3) and 2.014 (3) Å. In the crystal structure, one O,S-dibenzyl dithiophosphate counter-anion links with the CuII complex cation through N—H⋯O and N—H⋯S hydrogen bonding. During the synthesis, the structure of the anion re-arranged from O,O′-dibenzyl dithiophosphate in the starting material to O,S-dibenzyl dithiophosphate in the title compound.

Aqua­[2,6-bis­(2-pyridylamino)pyridine]sulfatonickel(II) monohydrate

The Ni atom in the title complex, [Ni(SO4)(C15H13N5)(H2O)]·H2O, has a distorted trigonal-bipyramidal coordination formed by the tridentate 2,6-bis(2-pyridylamino)pyridine (tpdaH2) ligand, one sulfate and one coordinated water molecule. The tpdaH2 ligand is three-coordinated, with the N atom of the central pyridine ring in the equatorial position [Ni—N = 1.9961 (14) Å] and the N atoms of the peripheral pyridine rings in the axial positions [Ni—N = 1.9668 (15) and 1.9895 (15) Å]. The remaining equatorial positions are occupied by the O atoms of the sulfate ligand and the water molecule. The H atoms of both NH groups of the tpdaH2 ligand are involved in hydrogen bonds with the O atoms of the uncoordinated water molecule and the sulfate group which link the complex molecules, forming an infinite three-dimensional network.

(meso-5,5,7,12,12,14-Hexamethyl-1,4,8,11-tetra­aza­cyclo­tetra­deca­ne)nickel(II) bis­[O,O′-(1,2-phenyl­ene) dithio­phosphate]

In the title salt-type 1:2 adduct, [Ni(C16H36N4)](C14H14O2PS2)2 or [Ni(tet-a)][S2P(OCH2Ph)2]2, where tet-a is meso-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, the [Ni(tet-a)]2+ complex cation exhibits a relatively undistorted square-planar geometry about the Ni atom, which lies on an inversion centre and is coordinated by four macrocyclic N atoms. The two O,O′-bis(2-phenylmethyl) dithiophosphate anions act as counter-ions to balance the charge and they interact with the complex through N—H⋯S hydrogen bonds. Important geometric data include Ni—N distances of 1.958 (3) and 1.963 (3) Å.