Christopher L. Edwards

Triethanolamine complexes of copper

Abstract A simple benchtop synthesis of the deep blue tetrameric compound [Cu{N(CH2CH2O)3H}]4 prepared from CuSO4·5H2O and triethanolamine is presented. The compound has been characterized in three different crystalline modifications which vary due to the presence of different lattice solvents that include THF, Et2O and H2O. The compound dissolves in water, alcohols and to a slight extent in dichloromethane and chloroform. It produces basic solutions (Kb=1.2 (±0.4)×10−7) in water and a visible spectrum that varies as a function of pH. FAB mass spectral data indicate that the tetramer remains intact and incorporates additional copper ions in the mass spectrometer.

Diels–Alder addition to fluorinated single walled carbon nanotubes

Fluorinated single walled carbon nanotubes (SWNTs) undergo a facile Diels-Alder [4 + 2] cycloaddition with a range of dienes resulting in a C ratio substituent ratio between 20 ratio 1 to 32 ratio 1; IR, Raman, AFM and (13)C NMR characterization are consistent with sidewall functionalization.

Molecular coupling layers formed by reactions of epoxy resins with self-assembled carboxylate monolayers grown on the native oxide of aluminium

In order to produce molecular coupling layers, epoxy resins cross-linked with self-assembled monolayers (SAMs) grown on the native oxide of aluminium have been investigated. Initially, SAMs were formed by the attachment of carboxylic acids, RCO2H [R = C17H35, CH3, C6H4-3-Br, C6H4-4-OH, and C(NH2)(CH2)4NH2], to the native oxides of aluminium thin films on silicon substrates. In order to investigate the cross-linking reaction between carboxylate monolayers and an epoxide, grown monolayers of p-hydroxybenzoic acid and lysine were reacted with a mono-epoxy resin, 1,2-epoxy-3-phenoxypropane. The SAM systems have been characterized by X-ray photoelectron spectroscopy, electron dispersive X-ray analysis, and contact angle measurements. In addition to these surface materials, aluminium oxide surfaces supporting either lysine or p-hydroxybenzoic acid monolayers were reacted in pairs with a di-epoxide (the diglycidyl ether of bisphenol-A) to form an adhesive layer between the two surfaces. Finally, this epoxide–SAM interaction is shown to form a “molecular glue”-type interface, which has been characterized by scanning electron microscopy.

A study of the formation, purification and application as a SWNT growth catalyst of the nanocluster [HxPMo12O40⊂H4Mo72Fe30(O2CMe)15O254(H2O)98]

The synthetic conditions for the isolation of the iron-molybdenum nanocluster FeMoC [HxPMo12O40 [subset]H4Mo72Fe30(O2CMe)15O254(H2O)98], along with its application as a catalyst precursor for VLS growth of SWNTs have been studied. As-prepared FeMoC is contaminated with the Keplerate cage [H4Mo72Fe30(O2CMe)15O254(H2O)98] without the Keggin [HxPMo12O40]n- template, however, isolation of pure FeMoC may be accomplished by Soxhlet extraction with EtOH. The resulting EtOH solvate is consistent with the replacement of the water ligands coordinated to Fe being substituted by EtOH. FeMoC-EtOH has been characterized by IR, UV-vis spectroscopy, MS, XPS and 31P NMR. The solid-state 31P NMR spectrum for FeMoC-EtOH (delta-5.3 ppm) suggests little effect of the paramagnetic Fe3+ centers in the Keplerate cage on the Keggin ions phosphorous. The high chemical shift anisotropy, and calculated T1 (35 ms) and T2 (8 ms) values are consistent with a weak magnetic interaction between the Keggin ions phosphorus symmetrically located within the Keplerate cage. Increasing the FeCl2 concentration and decreasing the pH of the reaction mixture optimizes the yield of FeMoC. The solubility and stability of FeMoC in H2O and MeOH-H2O is investigated. The TGA of FeMoC-EtOH under air, Ar and H2 (in combination with XPS) shows that upon thermolysis the resulting Fe : Mo ratio is highly dependent on the reaction atmosphere: thermolysis in air results in significant loss of volatile molybdenum components. Pure FeMoC-EtOH is found to be essentially inactive as a pre-catalyst for the VLS growth of single-walled carbon nanotubes (SWNTs) irrespective of the substrate or reaction conditions. However, reaction of FeMoC with pyrazine (pyz) results in the formation of aggregates that are found to be active catalysts for the growth of SWNTs. Activation of FeMoC may also be accomplished by the addition of excess iron. The observation of prior works reported growth of SWNTs from FeMoC is discussed with respect to these results.

Molecular structures of M(tfac)3 (M=Al, Co) and Cu(H2O)(fod)2 : Examples of unusual supramolecular architecture

The molecular structures of Al(tfac)3 (1), Co(tfac)3 (2) (H-tfac = 1,1,1-trifluoroacetylacetone) and Cu(H2O)(fod)2 (3) (H-fod = 1,1,1,2,2,3,3-hepta-fluoro-7,7-dimethyloctane-4,6-dione) have been determined. The metal coordination spheres in compounds 1 and 2 are essentially the same as the respective M(acac)3 derivatives. Despite the isomorphous nature of the structures of compounds 1 and 2, the identity of the nearest intermolecular van der Waals contacts are altered by minor changes in the metal coordination sphere. The geometry about copper in compound 3 is close to that of an ideal square bipyramid with the β-diketonate ligands occupying the basal plane. The water ligand in each molecule of compound 3 is hydrogen bonded to an oxygen of a β-diketonate ligand on an adjacent molecule resulting in the formation of dimers, which form rods along the y-axis due to weak C–F···Cu interactions. Crystal data: (1) orthorhombic, Pca21, a = 14.949(3), b = 19.806(4), c = 13.624(3) Å, V = 4033(1) Å3, and Z = 8, and (2) orthorhombic, Pca21, a = 14.930(3), b = 19.620(4), c = 13.540(3) Å, V = 3966(1) Å3, and Z = 8,; (3) monoclinic, P21/c, a = 12.447(3), b = 10.486(2) c = 21.980(4) Å, β = 102.65(3)°, V = 2799(1) Å3, and Z = 4.