Extension of Fourier Transform Vibrational Circular Dichroism into the Near-Infrared Region: Continuous Spectral Coverage from 800 to 10 000 cm−1

We present the results of a new Fourier transform infrared vibrational circular dichroism (FT-IR-VCD) spectrometer optimized for performance in the near-infrared region above 2000 cm−1. The instrument is capable of operating in either the conventional rapidscan mode or the step-scan mode and is designed around the Bruker IFS 55 FT-IR spectrometer. We find that in the region of hydrogen stretching, the instrument performs as well as or better than (depending on the spectral coverage and resolution desired) a corresponding dispersive grating VCD spectrometer, with noise levels at approximately 10−6 Δ A units for a two-hour collection at 8-cm−1 resolution. The performance is approximately a factor-of-2 better in signal-to-noise ratio in optimized step-scan operation in comparison to the corresponding results in rapid-scan operation. The reasons are traced to advantages in electronic filtering and undersampling efficiency in step-scan mode. It is expected that the advantages of step-scan will increase with increasing optical transition frequency, such as the region of overtone and combination bands between 4000 and 8000 cm−1.

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Chiral carbazole-based porphyrins showing absorption and circular dichroism in the near-infrared region

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424619500937 ◽

2020 ◽

Vol 24 (01n03) ◽

pp. 247-251

Author(s):

Chihiro Maeda ◽

Tadashi Ema

Keyword(s):

Circular Dichroism ◽

Near Infrared ◽

Infrared Region ◽

Nir Absorption ◽

Near Infrared Region ◽

Induced Aggregation ◽

First Time ◽

Circular Dichroïsm

Chiral carbazole-based porphyrins were synthesized for the first time via the incorporation of hydrobenzoin units at the thiophene moieties. They showed absorption and circular dichroism in the near-infrared (NIR) region. The NIR absorption was further red-shifted by solvent-induced aggregation.

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The nature of haem a3 in the oxidized state of cytochrome c oxidase. Evidence from low-temperature magnetic-circular-dichroism spectroscopy in the near infrared region

Biochemical Journal ◽

10.1042/bj2070167 ◽

1982 ◽

Vol 207 (1) ◽

pp. 167-170 ◽

Cited By ~ 23

Author(s):

A J Thomson ◽

D G Englinton ◽

B C Hill ◽

C Greenwood

Keyword(s):

Circular Dichroism ◽

Cytochrome C ◽

Cytochrome C Oxidase ◽

Near Infrared ◽

Magnetic Circular Dichroism ◽

Infrared Region ◽

Magnetic Circular Dichroism Spectroscopy ◽

Near Infrared Region ◽

Circular Dichroïsm ◽

Inhibited Enzyme

The magnetic-circular-dichroism (m.c.d.) spectra of oxidized ‘resting’ bovine cytochrome c oxidase and the cyanide-inhibited form are reported at 5.15 T and at 4.2 K along with m.c.d. magnetization curves plotted at selected wavelengths. In both spectra there are features at 790nm and 1564nm due to Cua and haem a respectively, the e.p.r.-detectable components of the enzyme. There is a new peak at 1946nm only in the spectrum of the cyanide-inhibited enzyme. Arguments are advanced that assign this to low-spin ferric haem a3 bridged to Cua3, thereby forming a ferromagnetically coupled pair of metal ions.

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Observation of Fourier Transform Near-Infrared Vibrational Circular Dichroism to 6150 cm−1

Applied Spectroscopy ◽

10.1366/000370203769699108 ◽

2003 ◽

Vol 57 (10) ◽

pp. 1245-1249 ◽

Cited By ~ 23

Author(s):

Laurence A. Nafie ◽

Rina K. Dukor ◽

Jean-René Roy ◽

Allan Rilling ◽

Xiaolin Cao ◽

...

Keyword(s):

Fourier Transform ◽

Circular Dichroism ◽

Near Infrared ◽

Vibrational Circular Dichroism ◽

Circular Dichroïsm

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Universal Spectropolarimeter Based on Overtone Circular Dichroism Measurements in the Near-Infrared Region

Analytical Chemistry ◽

10.1021/ac00093a017 ◽

1994 ◽

Vol 66 (21) ◽

pp. 3639-3643 ◽

Cited By ~ 6

Author(s):

Chieu D. Tran ◽

Victor I. Grishko

Keyword(s):

Circular Dichroism ◽

Near Infrared ◽

Infrared Region ◽

Near Infrared Region ◽

Circular Dichroïsm

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Enantiomeric Excess Determination by Fourier Transform Near-Infrared Vibrational Circular Dichroism Spectroscopy: Simulation of Real-Time Process Monitoring

Applied Spectroscopy ◽

10.1366/0003702055012573 ◽

2005 ◽

Vol 59 (9) ◽

pp. 1114-1124 ◽

Cited By ~ 18

Author(s):

Changning Guo ◽

Rekha D. Shah ◽

Rina K. Dukor ◽

Xiaolin Cao ◽

Teresa B. Freedman ◽

...

Keyword(s):

Fourier Transform ◽

Circular Dichroism ◽

Real Time ◽

Near Infrared ◽

Fractional Composition ◽

Enantiomeric Excess ◽

Flow Cell ◽

Vibrational Circular Dichroism ◽

Chiral Molecules ◽

Circular Dichroïsm

The first use of near-infrared (NIR) Fourier transform vibrational circular dichroism (FT-VCD) to follow changes in the enantiomeric excess (EE) of chiral sample molecules in time using a flow-cell sampling apparatus is reported. Simultaneous changes in the fractional composition and the EE of a mixture of two different chiral molecules were monitored as a function of time. This simulates the progress of the chemical reaction from a chiral reactant to a chiral product where the mole fractions and EE values of both species may change with time. For the molecules studied, α-pinene, camphor, and borneol, the accuracy of following EE changes for one species alone is approximately 2%, while for simultaneously following EE changes in two species it is approximately 3% for 30 min sampling periods at 16 cm−1 spectral resolution. These findings demonstrate the potential for VCD to be used in the NIR region for real-time monitoring of the composition and %EE of chemical reactions involving the synthesis of chiral molecules.

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