Scott J. Kirkby

A theoretical and experimental study of Sb4O6: vibrational analysis, infrared, and Raman spectra

The first ab initio theoretical study of tetraantimony hexoxide (Sb4O6) is reported. The normal mode frequencies, intensities, and the corresponding vibrational assignments of Sb4O6 in T(d) symmetry were calculated using the GAUSSIAN 98 set of quantum chemistry codes at the Hartree-Fock (HF)/CEP-121G, Møller-Plesset (MP2)/CEP-121G, and density functional theory (DFT)/B3LYP/CEP-121G levels of theory. By comparison to experimental data deduced by our laboratory and others, correction factors for the calculated vibrational frequencies were determined and compared. Normal modes were decomposed into three non-redundant motions (Sb-O-Sb stretch, Sb-O-Sb bend, and Sb-O-Sb wag). Percent relative errors found for the HF, DFT, and MP2 corrected frequencies when compared to experiment are 5.8, 6.1, and 5.7 cm(-1), respectively. Electron distributions for selected molecular orbitals are also considered.

Acid-Free Nitration of Benzene and Toluene in Zeolite NaZSM-5

The syntheses of nitrobenzene and p-nitrotoluene directly from benzene, toluene, and NO2 within the pore network of the initially acid-free zeolite NaZSM-5 are reported for the first time. The active species , formed by the interaction of NO2 with the Na

Selective Nitration of Chlorobenzene by NO2 in the Alkali Zeolite NaZSM-5

Chlorobenzene was reacted with NO2, in the initially acid-free zeolite NaZSM-5, to yield para-chloronitrobenzene exclusively. The precursors were loaded sequentially into self-supporting pellets of the zeolite, contained within a stainless steel cell, from the gas phase. The reaction proceeds spontaneously at room temperature. It is, however, very temperature dependent and effectively ceases at zero degrees Celsius. The reaction was monitored in situ using FT-IR. The active nitrating agent is formed from the partial electron donation by the NO2 to the Na

Synthesis of Large Crystal Transition Metal Substituted Zeolite ZSM-5

Crystals of ZSM-5 containing Cu, Mn, and Fe have been synthesized up to 85 μm in length along the long axis. This is 1 to 2 orders of magnitude larger than any previously reported. Phase identification was accomplished by powder XRD. A modified Charnel’s method was used to chelate the transition metal and the aluminum in the synthesis gel. Elemental analysis was performed by ICP-AES, confirming the presence of the metals. The metals are resistant to leaching under ion exchange and, as determined by partial dissolution, incorporated throughout the volume of the crystals.

Spectroscopy of iron germanium sulfide open-framework materials and precursors

The electronic and vibrational spectroscopy of one family of metal germanium sulfide open-framework materials, designated Cat{sub 2}FeGe{sub 4}S{sub 10} (Cat = (CH{sub 3}){sub 4}N, Cs), along with their precursor Cat{sub 4}Ge{sub 4}S{sub 10} germanium sulfide clusters have been studied. Ultraviolet-visible and mid-infrared reflectance spectroscopy has been used to study the electronic states. The reflectance spectroscopy of the frameworks is dominated by the d-d transitions of the Fe(II) in a S{sub 4} symmetry site. The vibrational spectroscopy has been analyzed by Fourier transform Raman. The frameworks are weakly vibrationally coupled. Their spectra contain vibrational modes that are nearly identical in frequency to those of the isolated cluster. There is a fortuitous window in the cluster vibrations in which framework modes of the Fe(II) center can be observed. In addition computational methods have been used to model the experimental results.