Enhanced microwave synthesis of polyaniline nanomaterials

Energy- and time-efficient enhanced microwave syntheses (EMS) of polyaniline (PANI) have been carried out. The GPC results showed that the molecular weight of the microwave-generated materials depends on the applied microwave power. FTIR spectroscopies confirmed the formation of PANI. The presence of a mixed morphology with the prevalence of nanofibers with different aspect ratios is confirmed through SEM. The conductivity of the samples (ca. 3-3.5 S cm-1) is found to be relatively independent on the microwave power levels. The fact that the molecular weight depends on the power means that this approach can be fine-tuned to optimize conditions for a specific material using different power levels

Surface science of soft scorpionates

The chemisorption of the soft scorpionate Li[PhTmMe] onto silver and gold surfaces is reported. Surface enhanced Raman spectroscopy in combination with the Raman analysis of suitable structural models, namely, [Cu(κ3-S,S,S-PhTmMe)(PCy3)], [Ag(κ3-S,S,S-PhTmMe)(PCy3)], [Ag(κ2-S,S-PhTmMe)(PEt3)], and [Au(κ1-S-PhTmMe)(PCy3)], are employed to identify the manner in which this potentially tridentate ligand binds to these surfaces. On colloidal silver surface-enhanced Raman spectroscopy (SERS) spectra are consistent with PhTmMe binding in a didentate fashion to the surface, holding the aryl group in close proximity to the surface. In contrast, on gold colloid, we observe that the species prefers a monodentate coordination in which the aryl group is not in close proximity to the surface

IR spectroscopy of two polymorphs of copper(I) thiocyanate and of complexes of copper(I) thiocyanate with thiourea and ethylenethiourea

Syntheses and infrared spectroscopic studies are reported for two different polymorphs of copper(I) thiocyanate and for adducts of copper(I) thiocyanate with thiourea (`tu') and ethylenethiourea ('etu' = imidazolidine-2-thione; (CH2NH)(2)CS)). These include the previously reported complex CuSCN/etu (1 : 2), which has a trigonal monomeric structure, and CuSCN/etu (1 : 1), which has a three-dimensional polymeric structure. A mechanochemical/infrared study of the CuSCN: to (1 : 2) system showed that no 1 : 2 complex exists in this case, the product being a mixture of a 1 : 3 complex and a novel 1 : 0.5 complex. The latter complex was prepared both mechanochemically and from solution, and characterized by infrared and solid-state Cu-65 broadline NMR spectroscopy. Diagnostic ligand and metal-ligand bands in the IR and far-IR spectra are assigned for both polymorphs of CuSCN and for all of the complexes studied and are discussed in relation to the structures of the complexes

Control of reversible ligand insertion via supramolecular interactions in the solid state

Reversible insertion of a ligand molecule into the coordination sphere of a metal complex in the solid state by variation of associated supramolecular hydrogen-bonding interactions in the solid is demonstrated in studies of complexes of copper(I) nitrate with thiourea

Formation of polypyrrole and polythiophene within Cu2+- and H+-mordenite hosts studied by EPR and UV-VIS spectroscopy

The reactions of pyrrole and thiophene monomers in copper-exchanged mordenite have been investigated using EPR and UV–VIS absorption spectroscopy. The EPR spectra show a decrease in the intensity of the Cu2+ signal and the appearance of a radical signal due to the formation of oxidatively coupled oligomeric and/or polymeric species in the zeolite host. The reaction ceases when ca. 50% of the copper has reacted and differences in the form of the residual Cu2+ signal between the thiophene and pyrrole reactions suggest a greater degree of penetration of the reaction into the zeolite host for pyrrole, in agreement with previous XPS measurements. The EPR signal intensities show that the average length of the polymer chain that is associated with each radical centre is 15–20 and 5–7 monomer units for polypyrrole and polythiophene, respectively. The widths of the EPR signals suggest that these are at least partly due to small oligomers.\ud \ud The UV–VIS absorption spectra of the thiophene system show bands in three main regions: 2.8–3.0 eV (A), 2.3 eV (B) and 1.6–1.9 eV (D, E, F). Bands A and D–F occur in regions which have previously been observed for small oligomers, 4–6 monomer units in length. Band B is assigned to longer chain polythiophene molecules. We therefore conclude that the reaction between thiophene and copper-loaded mordenite produces a mixture of short oligomers together with some long chain polythiophene.\ud \ud The UV–VIS spectra of the pyrrole system show bands in the regions 3.6 eV (A), 2.7–3.0 eV (B, C) and 1.5–1.9 eV (D, F). Assignments of these bands are less certain than for the thiophene case because of the lack of literature data on the spectra of pyrrole oligomers