N″-sulphonylformamidrazones; preparation and characterisation

N′-Sulphonylformamidrazones have been prepared in good yields from the reaction between N-sulphonylformimidates and di- or tri-substituted hydrazines.The actual tautomeric form present has been shown to be a hydrazide imide by ¹³C NMR spectroscopy. ¹H and ¹³C NMR spectra showed the existence of a cis and a trans isomer in solution, arising from hindered rotation around the CN¹ bond.     

The preparation and characterisation of ruthenium cyanovinylidene complexes

Reactions of half-sandwich ruthenium metal acetylide complexes with 1-cyano-4-dimethylaminopyridinium salts afford complexes containing mono- or di-cyanovinylidene ligands; the procedure can be adapted to permit the simple synthesis of a cyanoacetylide complex, via the in situ deprotonation of a primary cyanovinylidene complex.     

The preparation and characterisation of novel polyether gels

Poly(ethylene oxide)s end-capped with n-alkane chains (C₁₆-C₂₁) have been found to form stable gels in aqueous media. The crosslinks are believed to occur through association of the n-alkane chains. The dependence of the degree of swelling of the gels on the lengths of the alkane and poly(ethylene oxide)(M_n= 10000, 20000 and 30000) chains were studied. Degrees of swelling have been compared with results predicted by simple network theory.     

Electrochemical preparation and characterisation of CoPt magnetic particles

CoPt particles of different size and modulate magnetic properties have been prepared by electrodeposition. Particles of growing size from 50 nm until continuous deposits have been obtained and their composition, crystalline structure and magnetic properties have been analyzed. The prepared CoPt particles from 50 nm to 250 nm showed ferromagnetic behaviour so did the continuous deposits. However, drastic changes in magnetism have been detected related to the size of the particles: the smallest particles presented lower coercivity which increases with increasing size, with a maximum value for particles of 150–250 nm diameter. The coercivity decreased when continuous deposits were attained due to the disordered growing and the loss of the surface anisotropy.     

Copper resinate: preparation, characterisation and study of degradation

This paper describes a method for the synthesis of Copper Resinate, which disappeared from artists' palettes in the eighteenth century. This was carried out by interpreting ancient recipes following a scientific approach. Its characterisation using Fourier Transform-Infrared Spectrometry and Gas Chromatography-Mass Spectrometry demonstrated that it is a mixture containing copper and oxidised abietic acids, mainly dehydroabietic and 7-oxo-dehydroabietic acids, formed during the preparation of the pigment and the curing of the paint layer. The composition of copper resinate paint layers, artificially aged by U.V. irradiation at 365 nm (UV), heating (T), and exposed to atmospheric pollutants (NOX) in a climatic chamber, was investigated. The combination of irradiation and temperature produced a change in colour along with a significant increase in the recovered amount of 7-oxo-dehydroabietic acid. The identification of copper resinate in a sample from an old painting should be related to the presence of the following resin compounds which are stable in the ageing process: dehydroabietic and 7-oxo-dehydroabietic acid pimaradienic acids. Photo-oxidation of the resin acids co-ordinated with copper seem to be the most probable decay mechanism responsible for the colour change in the pigment.     

The preparation and characterisation of some new binary fluorides of antimony

Antimony pentafluoride acts as a useful oxidising agent towards many non-metals, giving interesting cations, and in the process is itself reduced. It would be helpful to know what the reduced products are, and under what conditions they are formed. Therefore, SbF₅ and the known SbF₅·SbF₃⁽¹⁾ in AsF₃ solution were reduced by iodine and/or PF₃ giving crystals of the new adduct, (SbF₃)₆(SbF₅)₅ [Monoclinic, a = 11.638(1), b = 8.995(1), c = 16.723(3) ā, β = 106.81(1)°, P2₁/c]; (SbF₃)₅(SbF₅)₃ [Orthorhombic, a = 19.187(9), b = 15.890(2), c = 15.713(3) ā, Pnma] and (SbF₃)₃SbF₅ [Monoclinic, a = 10.895(3), b = 10.941(3), c = 4.772(1) ā, β = 96.66(3)°, P2₁/m]. (SbF₃)₃SbF₅ seemed to be the most reduced adduct, no evidence was obtained for (SbF₃)_n(SbF₅) n > 3, under these conditions. The (SbF₃)₆(SbF₅)₅ adduct has a Raman spectrum identical to that reported by Gillespie⁽²⁾ and coworkers for an adduct of approximate composition SbF₃·SbF₅ and has a very different structure to that of (SbF₃)₆(SbF₆)₅ reported by Edwards.⁽³⁾ The crystal structures of the new adducts will be discussed and the cations they contain compared with those found in SbF₃·SbF₅⁽¹⁾ and (SbF₅)₆(SbF₅)₅⁽³⁾ (Edward's form).     

Microgravimetric preparation and characterisation of catalyst candidates for fuel cell electrodes

In the search for noble-metal-free cathode materials resistant to acid electrolytes and capable of catalysing the conversion of oxygen, thermogravimetric methods have been used to determine the conditions of preparation, to analyse the chemical properties, and to characterise the pore structure of the potential catalysts. The paper comprises results of investigations on inorganic compounds, such as ammonium tungstates, chromates, vanadates, molybdate and permanganate, and on organic polymers, such as polyamide nitriles, other CN polymers and polyacenoquinone pyrolysates.     

The preparation and characterisation of some new CF3Se-derivatives

The preparation and characterisation of CF₃SePF₂, CF₃SeSi(CH₃)₃ and CF₃SeTl(CH₃)₂ are described. The vibrational and n.m.r. spectra of these compounds are presented and discussed.     

Photoactive liquid polysulfides: preparation, characterisation, photocuring and potential applications

Photoactive terminal groups X have been introduced into liquid polysulfides to give X(SCH₂CH₂OCH₂OCH₂CH₂S)_nX where X=acetyl, acryloyl, cinnamoyl, benzoyl, I-naphthaloyl, oxalyl, p-toluene sulfonyl, terephthaloyl, 1,3,5-benzene tricarbonyl and methylvinylsilyl. The resulting modified LPs have been characterised by IR, UV, ¹NMR spectroscopy, size exclusion chromatography and ESI and FAB mass spectrometry. The results of photoirradiating these materials were examined and some selected for further study with regard to their potential application as coatings, adhesives and photoresists, both as such and as components of formulations. While the slowness of cure of the modified LPs presents a difficulty, they function satisfactorily as components of established photocurable compositions, conferring advantages in a number of cases (scratch resistance, speed of cure, hardness).     

Electrochemical preparation and characterisation of bilayer films composed by Prussian Blue and conducting polymer

Preparation and electrochemical behaviour of bilayer films consisting of iron(III) hexacyanoferrate, well known as Prussian Blue, and of poly[4,4^′-bis(butylsulphanyl)-2,2^′-bithiophene], on a platinum electrode, are reported. The electrochemical features of the Prussian Blue/conducting polymer bilayer system are examined in aqueous and acetonitrile solutions. Cyclic voltammetric studies show that, in acetonitrile solvent, the inner layer Prussian Blue is electroactive to some extent, though the electrochemical response of the system is mainly accounted for by poly[4,4^′-bis(butylsulphanyl)-2,2^′-bithiophene] outer layer. On the other hand, in aqueous solution Prussian Blue exhibits good electroactivity. Under specific experimental conditions, the individual redox behaviour of each constituent of the bilayer is evidenced in the two solvents separately, i.e., that of PB and that of poly[4,4^′-bis(butylsulphanyl)-2,2^′-bithiophene] in aqueous and in organic solvent, respectively. However, interesting reciprocal influences are evident in the current/potential curves recorded under conditions which are discussed.     

Importance of sample preparation on reliable surface characterisation of nano‐objects: ISO standard 20579‐4

The international ISO Standard 20579‐4, dealing with the history and preparation of nano‐objects for surface analysis, has been developed to help address some of the replication and reproducibility issues caused by the fundamental nature of nano‐objects. Although all types of samples requiring surface analysis need thoughtful preparation, nano‐objects, for which many properties are controlled by their surfaces, present additional challenges in order to avoid variations and artefacts due to the handling and preparation of materials prior to analysis. This international standard is part of a series of standards related to preparation of samples for surface chemical analysis. Parts 1 and 2 of ISO Standard series 20579 address general issues that apply to many samples. Part 3, which is still in development, will focus on biomaterials. Part 4 specifically considers issues that arise due to the inherent nature of nano‐objects. Because of sensitivity to their environment, the standard indicates the minimum information that needs to be reported about the handling and preparation of nano‐objects prior to surface analysis. This information should become part of sample provenance information that helps assure the reliability and usefulness of data obtained from surface‐analysis in the context of the synthesis, processing, and analysis history of a batch of material. Application of this standard can help address reproducibility and traceability issues associated with synthesis, processing, and characterization of nano‐objects in research and commercial applications.     

The preparation and characterisation of hetero- and homobimetallic complexes containing bridging naphthalene-1,8-dithiolato ligands

Homo- and heterobimetallic complexes of the form [(PPh(3))(2)(mu(2)-1,8-S(2)-nap){ML(n)}] (in which (1,8-S(2)-nap)=naphtho-1,8-dithiolate and {ML(n)}={PtCl(2)} (1), {PtClMe} (2), {PtClPh} (3), {PtMe(2)} (4), {PtIMe(3)} (5) and {Mo(CO)(4)} (6)) were obtained by the addition of [PtCl(2)(NCPh)(2)], [PtClMe(cod)] (cod=1,5-cyclooctadiene), [PtClPh(cod)], [PtMe(2)(cod)], [{PtIMe(3)}(4)] and [Mo(CO)(4)(nbd)] (nbd=norbornadiene), respectively, to [Pt(PPh(3))(2)(1,8-S(2)-nap)]. Synthesis of cationic complexes was achieved by the addition of one or two equivalents of a halide abstractor, Ag[BF(4)] or Ag[ClO(4)], to [{Pt(mu-Cl)(mu-eta(2):eta(1)-C(3)H(5))}(4)], [{Pd(mu-Cl)(eta(3)-C(3)H(5))}(2)], [{IrCl(mu-Cl)(eta(5)-C(5)Me(5))}(2)] (in which C(5)Me(5)=Cp*=1,2,3,4,5-pentamethylcyclopentadienyl), [{RhCl(mu-Cl)(eta(5)-C(5)Me(5))}(2)], [PtCl(2)(PMe(2)Ph)(2)] and [{Rh(mu-Cl)(cod)}(2)] to give the appropriate coordinatively unsaturated species that, upon treatment with [(PPh(3))(2)Pt(1,8-S(2)-nap)], gave complexes of the form [(PPh(3))(2)(mu(2)-1,8-S(2)-nap){ML(n)}][X] (in which {ML(n)}[X]={Pt(eta(3)-C(3)H(5))}[ClO(4)] (7), {Pd(eta(3)-C(3)H(5))}[ClO(4)] (8), {IrCl(eta(5)-C(5)Me(5))}[ClO(4)] (9), {RhCl(eta(5)-C(5)Me(5))}[BF(4)] (10), {Pt(PMe(2)Ph)(2)}[ClO(4)](2) (11), {Rh(cod)}[ClO(4)] (12); the carbonyl complex {Rh(CO)(2)}[ClO(4)] (13) was formed by bubbling gaseous CO through a solution of 12. In all cases the naphtho-1,8-dithiolate ligand acts as a bridge between two metal centres to give a four-membered PtMS(2) ring (M=transition metal). All compounds were characterised spectroscopically. The X-ray structures of 5, 6, 7, 8, 10 and 12 reveal a binuclear PtMS(2) core with PtM distances ranging from 2.9630(8)-3.438(1) A for 8 and 5, respectively. The napS(2) mean plane is tilted with respect to the PtP(2)S(2) coordination plane, with dihedral angles in the range 49.7-76.1 degrees and the degree of tilting being related to the PtM distance and the coordination number of M. The sum of the Pt(1)coordination plane/napS(2) angle, a, and the Pt(1)coordination plane/M(2)coordination plane angle, b, a+b, is close to 120 degrees in nearly all cases. This suggests that electronic effects play a significant role in these binuclear systems.     

N-sulphonylformamidrazones; preparation and structure

Potentially tautomeric N-sulphonylformamidrazones and models with fixed amide-hydrazone and hydrazide-imide structure have been prepared. The compounds with tautomeric possibilities have been shown to exist only in the amide-hydrazone form by ¹³C and ¹H NMR spectroscopy. The same compounds exist as two rotamers in solution arising hindered rotation around the NCHN single bond.     

Synthesis and structural characterisation of gallium and indium fluoroalkoxide ‘ate’ complexes

The treatment of InCl₃ with MOCH(CF₃)₂ (M = Li, Na, K) in a 1:6 stoichiometry, followed by recrystallisation results in the formation of the bimetallic “ate” complexes [Na₃In(OCH(CF₃)₂)₆(THF)₃] (2) and [Li₃In(OCH(CF₃)₂)₆(THF)₃] (5) from hexane, and [K₃In(OCH(CF₃)₂)₆]_n (4) from a THF and toluene mixture. If a 1:3 stoichiometry is used chloride containing compounds [Na₂InCl(OCH(CF₃)₂)₄(THF)₄] (1) and [KInCl₂ (OCH(CF₃)₂)₂(THF)₃]_n · THF (3) are obtained on recrystallisation from hexane. Treatment of GaCl₃ with 6 equivalents of LiOC(CH₃)₂CF₃ gives [LiGa(OC(CH₃)₂CF₃)₄(THF)₂] (6) on recrystallisation from hexane. The protolysis reaction between In(N(SiMe₃)₂)₃, formed in situ from (Me₃Si)₂NH, ⁿBuLi and Incl₃, and HOCH(CH₃)CF₃ results in isolation of [LiIn(OCH(CH₃)CF₃)₃Bu]₂ (7) from hexane. The structures of 2, 4, and 5 all contain the tetranuclear core InO₆M₃. Compounds 1 and 3 have residual chloride; 1 is a trinuclear species with two THF ligands per Na, while 3 is a linear polymer. Compound 6 has a GaO₂Li four-membered parallelogram at its core. Complex 7 has a tetranuclear In₂O₆Li₂ core and an unexpected ⁿBu group on the In atoms. The coordination spheres of the alkali metals in 1-6 include solvated THF while 1-5 display additional close M?F interactions.     

Surface analytical characterisation of Nd:YAG-laser pre-treated Al Mg3 as a preparation for bonding

The contribution summarises results of the surface pre-treatment of Al Mg3 (EN-AW-5754) for bonding applications. Mainly the sheet samples were irradiated with a pulsed solid-state laser in different atmospheres. Afterwards the pre-treated surfaces were analysed by quantitative topographic measurements, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and electrochemical impedance spectroscopy (EIS). The effect of surface pre-treatment on the strength of adhesively bonded specimens was evaluated by tensile lap-shear strength tests. The results were compared with conventional pre-treatment methods, such as anodic oxidation and others.     

XPS characterisation of carbon‐coated alumina support

Hybrid carbon–alumina supports, synthesised by pyrolysis of grafted 4,4′‐methylenebis‐(phenylisocyanate) moiety on the alumina surface, were characterised by X‐ray photoelectron spectroscopy. The recorded Al 2p and C 1s envelopes showed asymmetry that decreased with an increase in carbon loading. In all experimental Al 2p envelopes, the high‐energy individual components at 75.3–75.9 eV were present along with the low‐energy component at 74.0 eV typical for Al₂O₃. In the case of the C 1s envelope, the component around 284.3–284.4 eV and three high‐energy individual components at 285.9–286.0, 288.0–288.3 and 290.1–290.6 eV were observed. The presence of the high‐energy Al 2p components can be explained considering the occurrence of a steady‐state charging of the different parts of insulating alumina supports. The component around 284.3–284.4 eV in C 1s envelopes can be attributed to carbon, which constitutes the coating and, hence, ensures surface conductivity. The component around 285.9–286.0 eV is connected with carbon in carbonaceous surface species, which do not form the conducting layer on the alumina support. Carbonaceous surface species associated with C? O, C?O and O?C? O groups in carbon coating can be also identified due to the presence of corresponding components in XPS spectra at 285.9–286.0, 288.0–288.3 and 290.1–290.6 eV. Copyright © 2006 John Wiley & Sons, Ltd.     

Transition metal complexes of 2-acetylpyridine o-hydroxybenzoylhydrazone (APo-OHBH): their preparation, characterisation and antimicrobial activity.

Coordination compounds of some transition metal ions with 2-acetylpyridene-o-hydroxybenzoylhydrazone (APo-OHBH) were synthesized. Their structures have been characterised by elemental analyses, electrical conductance, magnetic moments (at 25 degrees C) and spectral (IR, UV, NMR) studies. The fast atom bombardment (FAB) method was used for obtaining mass spectra of the positive ion FAB studies of the ligand and some metal complexes. The thermal behaviour of selected complexes was investigated by thermal gravimetrical analysis (TGA) and differential thermal analysis (DTA) techniques. The IR spectra show that the ligand acts in a neutral bidentate, neutral tridentate and/or mononegative tridentate fashion depending on the metal salt used and the medium of the reaction. Preliminary pharmacological tests on the ligand and its complexes showed some antimicrobial activity.