Optically transparent thin-layer electrodes:  ninhydrin reduction in an infrared transparent cell

Heineman, William R.; Burnett, J. N.; Murray, Royce W.

doi:10.1021/ac60269a019

Cited by 64 publications

(29 citation statements)

References 24 publications

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“…However, overlapping IR bands of oxidants and the instability of BChl-b considerably limit this access to model-compound spectra. A much more appropriate approach would be the electrochemical generation of radicals in a cell suited to IR spectroscopy (15,16). In a previous report (17), we have described an optically and IR transmitting, anaerobic, thin-layer electrochemical cell that allows Chl radicals to be generated and investigated in situ.…”

mentioning

confidence: 99%

Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria

Mäntele

Wollenweber

Nabedryk³

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

132

140

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The IR spectra of the bacteriochlorophyll a and b cations and the bacteriopheophytin a and b anions were obtained by using an ER and optically transparent electrochemical cell. Prominent effects of radical formation on the vibrational spectra were found for bands assigned to the ester, keto, and acetyl C=O groups and for vibrations from macrocycle bonds. The (radical-minus-neutral) difference spectra are compared to the light-induced difference spectra ofthe primary donor photooxidation and the intermediary acceptor photoreduction in the reaction center of photosynthetic bacteria. Light-induced absorbance changes from bacteriochlorophyll a-containing reaction centers bear striking similarities to the electrochemically induced absorbance changes observed upon formation ofbacteriochlorophyll a' in vitro. Comparison ofthe radical formation in vitro in a hydrogen-bonding or a nonhydrogen-bonding solvent suggests an ester C=O group hydrogen bonded in the neutral state but free in the cation state. For the keto C=O group, the same comparison indicates one free carbonyl group. The (anion-minus-neutral) difference spectra of bacteriopheophytin a and b exhibit a single band in the ester C=O frequency range. In contrast, two bands are observed in the difference spectra of the intermediary acceptor reduction in the reaction center of Rhodopseudomonas viridis.The higher frequency band exhibits a sensitivity to 'H-2H exchange, which suggests a contribution from a protonated carboxyl group of an amino acid side chain.In the primary events in photosynthesis, absorption of light leads to charge separation between electron donor and acceptor molecules. In the bacterial reaction center (RC), the primary electron donor (P) is a bacteriochlorophyll (BChl)-a or -b dimer, the intermediary electron acceptor (H) is a bacteriopheophytin (BPheo)-a or -b monomer, and the primary acceptor is a quinone. Spectroscopic data on these components have been reported (1-3), and, together with the high-resolution structure analysis (4-7), electron transport pathways can be visualized. Specific interactions of the pigment molecules with their polypeptide environment, in addition to pigment-pigment interactions, account for the spectral and redox properties of BChls in vivo. Among these interactions are external liganding to the Mg atom ofthe BChl (8) as well as hydrogen-bonding from pigment groups to polypeptide side chains (7,8). Although such interactions have been studied by resonance Raman (RR) and IR spectroscopy in model systems (8,9), details about the interactions in vivo both in the neutral and charge-separated state still have to be collected.In previous studies, we have used IR difference spectroscopy to investigate the molecular changes in bacterial RC and chromatophores concomitant with P photooxidation (10) as well as with H reduction (11). By using Fourier transform infrared (FTIR) difference spectroscopy, sensitivity can be high enough to detect single bonds. The light-induced FTIR difference spectra consist of a number ofcha...

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mentioning

confidence: 99%

Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria

Mäntele

Wollenweber

Nabedryk³

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

132

140

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“…Transparent electrochemical cells were utilized earlier [8,9]. This type of spectroelectrochemical cells usually needed optically transparent electrodes or the deposition of electrical wires on the IR windows.…”

Section: Introductionmentioning

confidence: 99%

A low temperature in situ infrared reflected absorbance spectroelectrochemical (LT IRRAS) cell

Liu

Jin

Cheng

2007

Journal of Electroanalytical Chemistry

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“…Since the first infrared thin-layer spectroelectrochemical method was reported in 1968 [3], several different designs for optically-transparent IR spectroelectrochemical thinlayer cells have been reported [11 -15]. For a nonaqueous solution, NaCl or other salt plates have been used for the optical window, while an external gasket, such as Teflon, was used to form a shallow gap between wall plates.…”

Section: Introductionmentioning

confidence: 99%

“…A typical thin-layer spectroelectrochemical setup is composed of a few parts including: two IR transmittable plates separated by a small gap forming a thin layer; an opticallytransparent working electrode between the two plates; and reference and counter electrodes contacting the solution in the thin-layer. In order to achieve a suitable IR transmittance through the working electrode, a metal micromesh electrode has been utilized in this work [3,22]. Figure 1 shows the proposed IR thin-layer cell.…”

Section: Introductionmentioning

confidence: 99%

Silicon Micromachined Infrared Thin‐Layer Cell for In Situ Spectroelectrochemical Analysis of Aqueous and Nonaqueous Solvent System

et al. 2005

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This article reports in situ FTIR monitoring of electrochemical reactions using a silicon-based thin-layer cell realized by micromachining fabrication technologies. The proposed device contains a silicon micromachined cavity cell integrated with a gold working electrode, a counter electrode, and a Ag/AgCl reference electrode. Electrochemical, spectroscopic, and spectroelectrochemical characteristics of the fabricated cell have been experimentally measured and exhibited a comparable performance to commercialized CaF 2 thin-layer cells. In situ spectroelectrochemical characteristics have been successfully tested for both 2 mM K 3 Fe(CN) 6 in an aqueous solution and 2 mM ferrocene in a dichloromethane solution using the fabricated thin-layer cell.

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Optically transparent thin-layer electrodes: ninhydrin reduction in an infrared transparent cell

Abstract: The construction and application of an infrared transparent thin-layer electrochemical cell are described. The properties of large optical thickness and small diffusional thickness are combined in the cell by use of

Cited by 64 publications

References 24 publications

Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria

Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria

A low temperature in situ infrared reflected absorbance spectroelectrochemical (LT IRRAS) cell

Silicon Micromachined Infrared Thin‐Layer Cell for In Situ Spectroelectrochemical Analysis of Aqueous and Nonaqueous Solvent System

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