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With (E/Z)-isomeric phytyl halides as side-chain materials, vitamin K 1 is synthesized via a Diels–Alder reaction to activate the free bridgehead hydrogen of 3 for the alkylation and a retro-Diels–Alder reaction to eliminate cyclopentadiene from 2 in a high yield, in which the configuration of the double bond in the phytyl side-chain is retained.

The surface-enhanced infrared spectrometry of p-nitrothiophenol and its disulfide on silver films has been investigated by using deposition from solution, from self-assembled monolayers, and from the vapor phase using a direct-deposition gas chromatography/infrared (GC-IR) interface. In solution, the thiophenol oxidizes to form the disulfide, which then adsorbs to the silver film. If a silver film is deposited on top of a layer of the disulfide, the resulting spectrum is strongly different from that seen with a silver under-layer, more closely resembling the spectrum obtained from the self-assembled monolayer. When a GC-IR interface is used, the presence of the enhancement appears to be correlated with temperature-dependent chemisorption.

With (E/Z)-isomeric phytyl halides as side-chain materials, vitamin K 1 is synthesized via a Diels–Alder reaction to activate the free bridgehead hydrogen of 3 for the alkylation and a retro-Diels–Alder reaction to eliminate cyclopentadiene from 2 in a high yield, in which the configuration of the double bond in the phytyl side-chain is retained.

A capillary electrophoretic (CE) system has been successfully interfaced to a Fourier transform infrared spectrometer. The advantage of such an interface is that analytes may be detected and often unequivocally identified without analyte derivatization. The interface consists of a stainless steel tube in which the CE capillary is placed and the two are held in contact with the use of a metal tee. A solvent elimination approach is used with the interface, so that analytes are deposited onto an infrared transparent window, that is, CaF2, and measured with the use of an infrared microscope. A critical component of this design is to provide an electrical connection at the end of the CE column to permit stable separations that allow for efficient transport of the sample onto the window. The interface produces an aerosol that is directed at the surface of the infrared transparent window. The use of a volatile electrolyte, along with the flow of helium, allows for partial evaporation of the electrolyte in flight and complete evaporation of the solvent and electrolyte on the surface of the window to produce a "dry", or neat, analyte deposit.

On-line micro- and semimicro-HPLC/FT-IR interfaces have been developed in our laboratory. These interfaces involve thermospray nebulization of the HPLC effluent and a modification of the Bio-Rad Tracer direct deposition GC/FT-IR interface. The detection limits for on-line narrow-bore HPLC/FT-IR measurements are at the low nanogram level. The performance of reversed-phase HPLC/FT-IR was tested at flow rates from 8 to 50 μl/min. The modified fused-silica and stainless-steel transfer lines developed for HPLC/FT-IR can also be used for direct deposition GC/FT-IR measurements. The feasibility of using the same instrument for on-line HPLC/FT-IR and GC/FT-IR direct deposition measurements has been demonstrated.

SEIRA spectra measured in the microtransmission mode have been used to investigate the chemistry of p-nitrothiophenol (PNTP) on silver films. By monitoring the S-H stretching band at ∼2550 cm−1, we demonstrated that PNTP dimerizes oxidatively when applied to bare ZnSe substrate or Ag surfaces from acetone or methanol solution under ambient conditions. SEIRA spectra of the PNTP dimer were measured on both silver underlayer and overlayer surfaces by casting films of the dimer from solution. The SEIRA spectrum of PNTP dimer on the Ag overlayer is very different from, and more enhanced than, the corresponding underlayer spectrum. We conclude that the S-S bond of the dimer is broken and Ag-S bonds are formed when energetic silver atoms are vapor deposited on a film of the PNTP dimer already on ZnSe plate. PNTP monomer was passed through a GC column and deposited on a 5-nm Ag layer on a ZnSe plate mounted in a direct deposition GC/FT-IR interface. At temperatures above −30 °C, the SEIRA spectrum of PNTP monomer...

In this work, a CE/FT-IR spectrometric interface was investigated and has been proven feasible based on a solvent elimination approach. We have designed a metal nebulizer CE/FT-IR interface and have successfully collected spectra at the nanogram level. Standard buffers may pose a significant problem in CE/FT-IR spectrometry in that the buffer absorbances may mask the analyte spectrum. Alternate buffers have been investigated and have been found to be suitable.

The cooperative chemisorption of multilayers of 2,4-dinitrobenzoic acid on a silver surface under high vacuum was studied by microtransmission infrared spectrometry. The fact that the antisymmetric stretching modes of the carboxylate and nitro groups are active in the SEIRA spectra of 2,4- and 3,5-dinitrobenzoic acid suggests that the bottom layer is adsorbed perpendicular to the metal surface with higher layers oriented obliquely. Multilayer cooperative chemisorption and the effect of the solvent on the SEIRA spectra of p-nitrobenzoic acid (PNBA) were also observed. The symmetric COO− stretch in the SEIRA spectra of multilayers of PNBA is split into a doublet. Because there is a weaker interaction between the COO− group of PNBA in the upper layers with the Ag surface than for the bottom layers, we assign the 1420 cm−1 component to the symmetric COO− stretch of the upper layers of PNBA and the 1387 cm−1 band to the corresponding mode of the lower layers.

Resonance Raman (RR) spectra are reported for CoII, NiII, CuII, ZnII, PdII, and CdII protoporphyrin IX dimethyl ester (PP) complexes. The reduction in frequency of their structure-sensitive bands are in the order NiII > CoII > PdII > CuII > ZnII > CdII, while the values of λmax for their electronic absorption spectra increase in the order PdII < NiII < CoII < CuII < ZnII < CdII. Empirical assignments for some of the stronger Raman bands of some metalloporphyrins are given. A detailed examination of the interaction between metal ions and the porphyrin ring shows that in planar metalloporphyrins, in addition to the fundamental co-ordinate bonds, both core-expansion effects and π-back-bonding effects exist. When the outer dx2–y2 orbital is occupied by metal electrons, core expansion predominates; if no outer dx2–y2 orbital electron is present, π-back-bonding contributes more than core expansion. Using this assumption, we can explain the spectral changes in both Raman and electronic absorption spectra satisfactorily. We suggest that the essence of the core-expansion mechanism is the multiplex result of the interactions between the outer electrons of metal ions with the electrons of the porphyrin ring and their steric interactions.