Zainudin Arifin

Triphenyltin derivatives of isothiazol-3(2H)-one 1,1-dioxides. Synthesis, Mössbauer spectra, some fungitoxicity data, and crystal structure of triphenylstannyl 1,2-benziosthiazol-3-(2H)-one 1,1-dioxide·N,N-dimethylformamide

The syntheses and tin-119m Mossbauer spectroscopic data are reported for two series of stannylimides, 2-triphenylstannyl 1,2-benziosithiazol-3(2H)-one 1,1-dioxide·L (L = O-donor ligand) and 2-triphenylstannyl 4,5-substituted isothiazol-3(2H)-one 1,1-dioxides, and for the stannylester, triphenyltin 1,2-benzisothiazol-3(2H-onyl-2-acetate 1,1-dioxide. The observed quadrupole splitting (QS) values (3.12–3.25 mm s−1) are interpreted in terms of trans-C3SnNo trigonal bipyramidal structures for the (C6H5)3SnNC(O)C6H4SO2·L [ L = (C6H5)2C2CO, (CH3)2NCHO, C9H7NO, (C6H5CH2)2SO, (C6H53PO, (C6H5)3AsO] adducts. A crystal structure determination of the N,N-dimethylformamide adduct confirms the Mossbauer assignment. The ipso-carbons [Sn-C 2.120(4), 2.120(5), 2.122(5) A] comprise the equatorial girdle of the trigonal bipyramid, the apical positions being occupied by the imido nitrogen [Sn−N 2.242(5) A] and amido oxygen [Sn–O 2.402(5) A] atoms. A similar five-coordinate structure is assigned to (C6H5)3SnNC(O)C(R′)C(R″)SO2 [Qs 2.95–3.32 mm s−1; R′ = R″ = CH3; R′ = H, R″ = C6H5; = −(CH2)4−; R′R″ = −(CH2)5−], but for the R′ = CH3, R″ = C6H5 derivative, the lower QS value (2.54 mm s−1) is more consistent with a four-coordinated tetrahedral structure. A trans-C3SnO2 trigonal bipyramidal structure for the (C6H5)3SnO2CCH2NC(O)C6H4SO2 stannylester is indicated by its large QS (3.53 mm s−1). Results on fungitoxicity tests on some of the triphenyltin compounds are presented.

Hexagonal structured Zn(1−x)CdxO solid solution thin films: synthesis, characterization and applications in photoelectrochemical water splitting

Hexagonal nanostructured zinc–cadmium oxide [Zn(1−x)CdxO where x = 0.08, 0.15, and 0.17] solid solution thin films were deposited on FTO coated glass substrates from a common solution of zinc acetate and a newly developed polymeric cadmium precursor by an aerosol-assisted chemical vapour deposition (AACVD) technique. The polymeric cadmium precursor [Cd3(TFA)4(OAc)2(THF)4]n (1) was synthesized by the reaction of cadmium(II)acetate dihydrate with triflouroacetic acid in THF solution and characterized by melting point, microanalysis, FTIR, 1H-NMR, thermogravimetry (TG/DTG) and single crystal X-ray analysis. The deposited thin films were characterized by powder XRD, SEM, EDX and UV-visible spectrophotometry, and tested for photoelectrochemical (PEC) water splitting to hydrogen and oxygen. The effect of various thin film deposition parameters such as solvent type, temperature and electrolyte concentration on PEC properties has been investigated. The SEM analysis illustrated that the morphology of the films changes significantly with the change of the solvent. The films deposited from THF solution have a needle-like appearance scattered vertically on the FTO-coated glass substrate. An optical band gap of 2.40 eV has been estimated by UV-visible spectrophotometry. The current–voltage characterization proved that the nanocrystalline hexagonal structured Zn0.83Cd0.17O electrodes exhibit an n-type semiconducting behaviour and the photocurrent was found to be strongly dependent on the deposition solvent, deposition temperature and electrolyte concentration. The maximum photocurrent density of 0.23 mA cm−2 at 0.55 V vs. Ag/AgCl/3 M KCl (∼1.23 V vs. RHE) was obtained for the Zn0.83Cd0.17O photoelectrode deposited at 500 °C for 45 min from 0.5 M solution of (1) and Zn(CH3COO)2·2H2O in THF.

Perovskite-structured PbTiO3 thin films grown from a single source precursor.

Perovskite-structured lead titanate thin films have been grown on FTO-coated glass substrates from a single-source heterometallic molecular complex, [PbTi(μ2-O2CCF3)4(THF)3(μ3-O)]2 (1), which was isolated in quantitative yield from the reaction of tetraacetatolead(IV), tetrabutoxytitanium(IV), and trifluoroacetic acid from a tetrahydrofuran solution. Complex 1 has been characterized by physicochemical methods such as melting point, microanalysis, FTIR, (1)H and (19)F NMR, thermal analysis, and single-crystal X-ray diffraction (XRD) analysis. Thin films of lead titanate having spherical particles of various sizes have been grown from 1 by aerosol-assisted chemical vapor deposition at 550 °C. The thin films have been characterized by powder XRD, scanning electron microscopy, and energy-dispersive X-ray analysis. An optical band gap of 3.69 eV has been estimated by UV-visible spectrophotometry.

Effects of [C6H5COONa] on rates of intramolecular general base-catalyzed piperidinolysis and n-butylaminolysis of ionized phenyl salicylate in the presence of cationic micelles

Abstract Pseudo-first-order rate constants (kobs), obtained for the cleavage of ionized phenyl salicylate (PS−) at constant [NaOH]; [C6H5COONa]; [MeCN]; [CTABr]T (total concentration of cetyltrimethylammonium bromide) and varying concentrations of n-butylamine and piperidine ([Am]T), follow the relationship: kobs=k0+knobs[Am]T. The values of k0 and knobs at different [CTABr]T and [C6H5COONa] are explained in terms of pseudophase model of micelle coupled with an empirical relationship: KS=KS0/(1+ψ[C6H5COONa]) where KS is the CTABr micellar binding constant of PS−. The calculated respective values of knsMKN (where KN is the micellar binding constant of amine and knsM=knM/VM with knM and VM representing nucleophilic second-order rate constant for the reaction of amine with PS− in the micellar pseudophase and micellar molar volume, respectively) and ψ are (12.2±0.6)×10−3 M−1 s−1 and 127±10 M−1 for n-butylamine and (14.8±1.7)×10−3 M−1 s−1 and 124±5 M−1 for piperidine. The values of KN for both amines turn out to be so small that they could not be determined kinetically. The values of k0 for n-butylamine are relatively more reliable and these k0 values yield khM (pseudo-first-order rate constant for hydrolysis of PS− in the micellar pseudophase) and ψ as (7.0±1.9)×10−5 s−1 and 104±21 M−1, respectively.

Nitrite ion sensing properties of ZnTiO3–TiO2 composite thin films deposited from a zinc–titanium molecular complex

A titanium based heterobimetallic molecular precursor, [Zn2Ti4(μ-O)6(TFA)8(THF)6]·THF (1) (where TFA = trifluoroacetato; THF = tetrahydrofuran), has been designed and scrutinised for its various physicochemical properties by melting point analysis, microanalysis, Fourier transform infra-red spectroscopy, proton nuclear magnetic resonance spectroscopy, thermogravimetry and single crystal X-ray structural analysis. ZnTiO3–TiO2 composite thin films were grown on a fluorine doped tin oxide (FTO) coated conducting glass substrate at 550 °C from three different solutions of (1) viz. methanol, THF and acetonitrile, by the aerosol-assisted chemical vapour deposition technique. The phase identification, chemical composition and microstructure of the fabricated thin films that were probed by powder X-ray diffraction, Raman spectroscopy, energy dispersive X-ray analysis and scanning electron microscopy revealed the formation of a 1 : 1 ratio of ZnTiO3 : TiO2 composite microspheres of diverse designs and textures depending on the type of deposition solvent used. The direct band gap energy of 3.1 eV was estimated by UV-visible spectrophotometry of the ZnTiO3–TiO2 film fabricated from methanol solution and the film electrode was further tested as an electrochemical sensor for the detection of nitrite ions.

A STRUCTURAL STUDY OF THE INTERACTION OF DIBENZYLDIAZA-18-CROWN-6 WITH NEODYMIUM(III) NITRATE HEXAHYDRATE

Abstract The structure of the complex salt, [C26H40N2O4][Nd(NO3)5(H2O)] (1), was determined by single crystal X-ray diffraction. It consists of alternating layers of the anionic complex, [Nd(NO3)5(H2O)]2−, and the cationic diprotonated [2H.azacrown]2+. The Nd3+ complex anion is coordinated to five bidentate nitrate ligands and a water ligand to give an 11-coordinated environment. Each Nd moiety is linked to another through intermolecular hydrogen bonding to form pairs of Nd moieties. The azacrown adopts a chair conformation and the benzyl groups are attached to the nitrogen atoms in an anti position with respect to each other, above and below the plane of the macro-ring in agreement with the conformation of the uncomplexed protonated azacrown as obtained by the PM3 method.

Effects of cationic micelles on the rate of intramolecular general base-catalyzed reaction of ionized phenyl salicylate (PS−) with Tris(hydroxymethyl)aminomethane (Tris)

Abstract Pseudo-first-order rate constants (kobs) obtained for the aminolysis of ionized phenyl salicylate (PS−) at a constant [NaOH] and [Surf] (where Surf=CTABr or CTACl with CTABr and CTACl representing cetyltrimethylammonium bromide and cetyltrimethylammonium chloride, respectively) and 35°C show a linear increase with increase in the total amine concentration. Nucleophilic second-order rate constants (knobs) for the reactions of Tris with PS− reveal a decrease of nearly ten- to 11-fold with the increase in [Surf] from 0.0 to 0.01 M. These observed data are explained in terms of the pseudophase model of the micelle. The CTABr and CTACl micellar binding constants (KN) of Tris appear to be so small that it could not be determined kinetically. The characteristic effect of CTABr micelles on knobs is similar to that of CTACl micelles. Significantly lower rate of aminolysis of PS− in the micellar pseudophase than that in aqueous pseudophase is partly or fully attributed to the different locations of PS− and Tris molecules in the micellar pseudophase.

A structural study of (dibenzyldiaza-18-crown-6) lanthanum(III) thiocyanate

Abstract The structure of the complex La(NCS) 3 C 26 H 38 N 2 O 4 ( 1 ) was determined by single-crystal X-ray diffraction and the structure of the coordinating ligand, C 26 H 38 N 2 O 4 ( 2 ), was studied by the semi-empirical PM3 method. The bonding around La consists of a primary coordination of three thiocyanate N atoms and a secondary coordination of two N atoms and four O atoms of the macrocycle. The primary coordination about La gives an almost planar trigonal configuration that bisects the plane of the macrocycle with La lying in the centre of the macrocycle cavity. The benzyl groups that are attached to the macrocycle are in syn conformation with respect to the macrocycle plane with one of the La–NCS bonds pointing above the plane and the other two La–NCS bonds pointing below the plane in the direction of the benzyl groups. The PM3 calculation shows that the optimised diazacrown has an open structure of a pseudo D 2d symmetry with the two benzyl side-arms positioned away from the cavity.

Bis(O-n-butyl dithio­carbonato-κ2 S,S′)bis­(pyridine-κN)manganese(II)

The structure of the title manganese complex, [Mn(C5H9OS2)2(C5H5N)2] or [Mn(S2CO-n-Bu)2(C5H5N)2], consists of discrete monomeric entities with Mn2+ ions located on centres of inversion. The metal atom is coordinated by a six-coordinate trans-N2S4 donor set with the pyridyl N atoms located in the apical positions. The observed slight deviations from octahedral geometry are caused by the bite angle of the bidentate κ2-S2CO-n-Bu ligands [69.48 (1)°]. The O(CH2)3(CH3) chains of the O-n-butyl dithiocarbonate units are disordered over two sets of sites with an occupancy ratio of 0.589 (2):0.411 (2).

Effect of mixed CH3CNH2O solvents on intramolecular general base-catalysed methanolysis of ionized phenyl salicylate (PS−) in the presence of cationic micelles

Abstract The increase in the content of CH3CN from 5 to 20%, v/v, decreases the cetyltrimethylammonium bromide (CTABr) micellar binding constant K1 of PS− from 4500 to 190 M−1, increases the critical micellar concentration from 2.89 × 10−4 to 39.8 × 10−4 M and increases the pseudo-first-order rate constants kM for methanolysis of PS− in the micellar pseudo-phase from 1.42 × 10−3 to 2.04 × 10−3 s−1. At constant concentrations of CH3CN and CH3OH, the rate constants k1 decrease with increase in [CTABr] and the amount of this decrease increases with decrease in [CH3CN]. The presence of 2 × 10−4 M PS− is concluded to enhance CTABr micelle formation.