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Tretyakov EV, Ovcharenko VI, Terent'ev AO, Krylov IB, Magdesieva TV, Mazhukin DG, Gritsan NP. Conjugated nitroxide radicals. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5025] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fidan I, Onal E, Hirel C. Nitroxide radicals appended to phthalonitriles: synthesis, structural characterization and photophysical properties. Acta Crystallogr C 2021; 77:137-143. [DOI: 10.1107/s2053229621001832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 02/14/2021] [Indexed: 11/10/2022] Open
Abstract
The syntheses of 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl-2-yl)phenoxy]phthalonitrile (3, C21H19N4O3) and 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-2-yl)phenoxy]phthalonitrile (4) were carried out by microwave-assisted nucleophilic aromatic substitution of 4-nitrophthalonitrile (2) by the pre-formed 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl (1). Compounds 3 and 4 were characterized unambiguously by a rich array of analyses, such as melting point, FT–IR, MALDI–TOF MS, elemental analysis, UV–Vis, CV, EPR, magnetic measurements and single-crystal X-ray diffraction. Structural studies demonstrate that the C—H...X and C—X...π (X = O and N) interactions in the radical nitronyl nitroxide groups play an important role in the assembly of the crystal structures. Moreover, cyclic voltammetry analyses show that the phthalonitrile substituent retains the redox properties of the Ullman radicals.
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Navarro Y, Guedes GP, Del Águila-Sánchez MA, Iglesias MJ, Lloret F, López-Ortiz F. Synthesis, crystal structures and magnetic properties of a P-stereogenic ortho-(4-amino-tempo)phosphinic amide radical and its Cu II complex. Dalton Trans 2021; 50:2585-2595. [PMID: 33522545 DOI: 10.1039/d0dt04298f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of phosphinic amides containing one 4-amino-TEMPO substituent at the ortho position has been achieved through copper(i) catalyzed cross-coupling reactions of ortho-iodophosphinic amides with 4-amino-TEMPO. The method has been extended to the preparation of the first example of a P-stereogenic ortho-(4-amino-tempo)phosphinic amide radical 10. The reaction of 10 with Cu(hfac)2 afforded the P-stereogenic CuII complex 19. The crystal structure of both chiral compounds is reported. The molecular structure of 10 consists of a supramolecular zig-zag chain formed by intermolecular hydrogen bonds between the NH group of the phosphinic amide moiety and the nitroxide oxygen atom. In complex 19, the ligand acts as a bridge between two CuII ions coordinated to the oxygen atoms of the P[double bond, length as m-dash]O and N-O· groups leading to the formation of a polymeric helicate chain in which the metal ions exist in a distorted octahedral geometry. The magnetic behavior of ligand 10 is characterized by very weak intermolecular antiferromagnetic interactions, whereas ferro- and anti-ferromagnetic interactions are present in complex 19.
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Affiliation(s)
- Yolanda Navarro
- Área de Química Orgánica, Centro de Investigación CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain.
| | - Guilherme P Guedes
- Universidade Federal Fluminense, Instituto de Química, Departamento de Química Inorgânica, Niterói, Rio de Janeiro, Brazil
| | - Miguel A Del Águila-Sánchez
- Área de Química Orgánica, Centro de Investigación CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain.
| | - María José Iglesias
- Área de Química Orgánica, Centro de Investigación CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain.
| | - Francisco Lloret
- Institut de Ciencia Molecular, Universitat de València, Catedràtic José Beltrán no.2, 46980 Paterna, Valencia, Spain
| | - Fernando López-Ortiz
- Área de Química Orgánica, Centro de Investigación CIAIMBITAL, Universidad de Almería, Carretera de Sacramento s/n, 04120 Almería, Spain.
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Keiderling TA. Structure of Condensed Phase Peptides: Insights from Vibrational Circular Dichroism and Raman Optical Activity Techniques. Chem Rev 2020; 120:3381-3419. [DOI: 10.1021/acs.chemrev.9b00636] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Timothy A. Keiderling
- Department of Chemistry, University of Illinois at Chicago 845 West Taylor Street m/c 111, Chicago, Illinois 60607-7061, United States
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De Zotti M, Syryamina VN, Hussain R, Longo E, Siligardi G, Dzuba SA, Stella L, Formaggio F. A Temperature-Driven, Reversible, Helical-Handedness Inversion in Peptaibol Analogues Tuned by the C-Terminal Capping Moiety. Chembiochem 2019; 20:2125-2132. [PMID: 31095838 DOI: 10.1002/cbic.201900235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Indexed: 11/07/2022]
Abstract
Trichogin is a natural peptide endowed with antimicrobial and antitumor activity. A member of the peptaibol family, trichogin possesses a C-terminal amino alcohol. In the past, this moiety was substituted for a methyl ester for synthetic purposes and it was observed that this apparently slight modification caused significant changes in the peptide bioactivity. With the aim of understanding the reasons behind such observations, a detailed spectroscopic study on a number of trichogin analogues has been performed. Herein, data obtained from synchrotron radiation circular dichroism, NMR spectroscopy, and fluorescence spectroscopy in organic solvents at cryogenic temperatures are compared with those independently acquired by means of EPR spectroscopy at 80 K. It is unambiguously revealed that the presence of a reversible, temperature-driven, screw-sense interconversion from a right- to left-handed helix is determined by the C-terminal capping moiety. Data demonstrate, for the first time, the key role of a C-terminal methyl ester in promoting peptide screw-sense inversion.
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Affiliation(s)
- Marta De Zotti
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131, Padova, Italy
| | - Victoria N Syryamina
- Institute of Chemical Kinetics and Combustion, RAS, Ulitsa Institutskaya 3, Novosibirsk, 630090, Russian Federation.,Novosibirsk State University, Ulitsa Pirogova 2, Novosibirsk, 630090, Russian Federation
| | - Rohanah Hussain
- Diamond Light Source Ltd., Harwell Innovation Campus, Chilton, Didcot, Oxfordshire, UK
| | - Edoardo Longo
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100, Bozen-Bolzano, Italy
| | - Giuliano Siligardi
- Diamond Light Source Ltd., Harwell Innovation Campus, Chilton, Didcot, Oxfordshire, UK
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, RAS, Ulitsa Institutskaya 3, Novosibirsk, 630090, Russian Federation.,Novosibirsk State University, Ulitsa Pirogova 2, Novosibirsk, 630090, Russian Federation
| | - Lorenzo Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, via della ricerca scientifica 1, 00133, Rome, Italy
| | - Fernando Formaggio
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131, Padova, Italy
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Nasrallah H, Rabah J, Bui-Thi-Tuyet V, Baczko K, Fensterbank H, Bourdreux F, Goncalves AM, Declerck V, Boujday S, Humblot V, Wright K, Vallée A, Allard E. A fullerene helical peptide: synthesis, characterization and formation of self-assembled monolayers on gold surfaces. NEW J CHEM 2018. [DOI: 10.1039/c8nj04599b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A helical C60-peptide allowed the formation of well-packed SAMs compared to a C60-alkyl peptide, which was determined by QCM and CV experiments.
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