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Pescitelli G, Kurtán T, Flörke U, Krohn K. Absolute structural elucidation of natural products--a focus on quantum-mechanical calculations of solid-state CD spectra. Chirality 2010; 21 Suppl 1:E181-201. [PMID: 19902530 DOI: 10.1002/chir.20795] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this review article we examine state-of-the-art techniques for the structural elucidation of organic compounds isolated from natural sources. In particular, we focus on the determination of absolute configuration (AC), perhaps the most challenging but inevitable step in the whole process, especially when newly isolated compounds are screened for biological activity. Among the many methods employed for AC assignment that we review, special attention is paid to electronic circular dichroism (CD) and to the modern tools available for quantum-mechanics CD predictions, including TDDFT. In this context, we stress that conformational flexibility often poses a limit to practical CD calculations of solution CD spectra. Many crystalline natural products suitable for X-ray analysis do not contain heavy atoms for a confidential AC assignment by resonant scattering. However, their CD spectra can be recorded in the solid state, for example with the KCl pellet technique, and analyzed possibly by nonempirical means to provide stereochemical information. In particular, solid-state CD spectra can be compared with those calculated with TDDFT or other high-level methods, using the X-ray geometry as input. The solid-state CD/TDDFT approach, described in detail, represents a quick and reliable tool for AC assignment of natural products.
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Affiliation(s)
- Gennaro Pescitelli
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Pisa, Italy.
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Autschbach J, Nitsch-Velasquez L, Rudolph M. Time-dependent density functional response theory for electronic chiroptical properties of chiral molecules. Top Curr Chem (Cham) 2010; 298:1-98. [PMID: 21321799 DOI: 10.1007/128_2010_72] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Methodology to calculate electronic chiroptical properties from time-dependent density functional theory (TDDFT) is outlined. Applications of TDDFT to computations of electronic circular dichroism, optical rotation, and optical rotatory dispersion are reviewed. Emphasis is put on publications from 2005 to 2010, but much of the older literature is also cited and discussed. The determination of the absolute configuration of chiral molecules by combined measurements and computations is an important application of TDDFT chiroptical methods and discussed in some detail. Raman optical activity (ROA) spectra are obtained from normal-mode derivatives of the optical rotation tensor and other linear response tensors. A few selected (ROA) benchmarks are reviewed.
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Affiliation(s)
- Jochen Autschbach
- Department of Chemistry, University at Buffalo State University of New York, New York, NY, USA.
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Pescitelli G, Sreerama N, Salvadori P, Nakanishi K, Berova N, Woody RW. Inherent Chirality Dominates the Visible/Near-Ultraviolet CD Spectrum of Rhodopsin. J Am Chem Soc 2008; 130:6170-81. [DOI: 10.1021/ja711009y] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Gennaro Pescitelli
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, Italy, Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, and Department of Chemistry, Columbia University, 3000 Broadway, MC 3114, New York 10027
| | - Narasimha Sreerama
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, Italy, Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, and Department of Chemistry, Columbia University, 3000 Broadway, MC 3114, New York 10027
| | - Piero Salvadori
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, Italy, Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, and Department of Chemistry, Columbia University, 3000 Broadway, MC 3114, New York 10027
| | - Koji Nakanishi
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, Italy, Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, and Department of Chemistry, Columbia University, 3000 Broadway, MC 3114, New York 10027
| | - Nina Berova
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, Italy, Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, and Department of Chemistry, Columbia University, 3000 Broadway, MC 3114, New York 10027
| | - Robert W. Woody
- Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Pisa, via Risorgimento 35, I-56126 Pisa, Italy, Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, and Department of Chemistry, Columbia University, 3000 Broadway, MC 3114, New York 10027
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