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Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered

Isocyanoazulenes (CNAz) constitute a relatively new class of isocyanoarenes that offers rich structural and electronic diversification of the organic isocyanide ligand platform. This article considers a series of 2-isocyano-1,3-X(2)-azulene ligands (X = H, Me, CO(2)Et, Br, and CN) and the correspond...

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Autores principales: Hart, Mason D., Meyers, John J., Wood, Zachary A., Nakakita, Toshinori, Applegate, Jason C., Erickson, Nathan R., Gerasimchuk, Nikolay N., Barybin, Mikhail V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918097/
https://www.ncbi.nlm.nih.gov/pubmed/33673291
http://dx.doi.org/10.3390/molecules26040981
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author Hart, Mason D.
Meyers, John J.
Wood, Zachary A.
Nakakita, Toshinori
Applegate, Jason C.
Erickson, Nathan R.
Gerasimchuk, Nikolay N.
Barybin, Mikhail V.
author_facet Hart, Mason D.
Meyers, John J.
Wood, Zachary A.
Nakakita, Toshinori
Applegate, Jason C.
Erickson, Nathan R.
Gerasimchuk, Nikolay N.
Barybin, Mikhail V.
author_sort Hart, Mason D.
collection PubMed
description Isocyanoazulenes (CNAz) constitute a relatively new class of isocyanoarenes that offers rich structural and electronic diversification of the organic isocyanide ligand platform. This article considers a series of 2-isocyano-1,3-X(2)-azulene ligands (X = H, Me, CO(2)Et, Br, and CN) and the corresponding zero-valent complexes thereof, [(OC)(5)Cr(2-isocyano-1,3-X(2)-azulene)]. Air- and thermally stable, X-ray structurally characterized 2-isocyano-1,3-dimethylazulene may be viewed as a non-benzenoid aromatic congener of 2,6-dimethyphenyl isocyanide (2,6-xylyl isocyanide), a longtime “workhorse” aryl isocyanide ligand in coordination chemistry. Single crystal X-ray crystallographic {Cr–CNAz bond distances}, cyclic voltametric {E(1/2)(Cr(0/1+))}, (13)C NMR {δ((13)CN), δ((13)CO)}, UV-vis {dπ(Cr) → pπ*(CNAz) Metal-to-Ligand Charge Transfer}, and FTIR {ν(N)(≡)(C), ν(C)(≡)(O), k(C)(≡)(O)} analyses of the [(OC)(5)Cr(2-isocyano-1,3-X(2)-azulene)] complexes provided a multifaceted, quantitative assessment of the π-acceptor/σ-donor characteristics of the above five 2-isocyanoazulenes. In particular, the following inverse linear relationships were documented: δ((13)CO(trans)) vs. δ((13)CN), δ((13)CO(cis)) vs. δ((13)CN), and δ((13)CO(trans)) vs. k(C)(≡)(O,trans) force constant. Remarkably, the net electron withdrawing capability of the 2-isocyano-1,3-dicyanoazulene ligand rivals those of perfluorinated isocyanides CNC(6)F(5) and CNC(2)F(3).
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spelling pubmed-79180972021-03-02 Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered Hart, Mason D. Meyers, John J. Wood, Zachary A. Nakakita, Toshinori Applegate, Jason C. Erickson, Nathan R. Gerasimchuk, Nikolay N. Barybin, Mikhail V. Molecules Article Isocyanoazulenes (CNAz) constitute a relatively new class of isocyanoarenes that offers rich structural and electronic diversification of the organic isocyanide ligand platform. This article considers a series of 2-isocyano-1,3-X(2)-azulene ligands (X = H, Me, CO(2)Et, Br, and CN) and the corresponding zero-valent complexes thereof, [(OC)(5)Cr(2-isocyano-1,3-X(2)-azulene)]. Air- and thermally stable, X-ray structurally characterized 2-isocyano-1,3-dimethylazulene may be viewed as a non-benzenoid aromatic congener of 2,6-dimethyphenyl isocyanide (2,6-xylyl isocyanide), a longtime “workhorse” aryl isocyanide ligand in coordination chemistry. Single crystal X-ray crystallographic {Cr–CNAz bond distances}, cyclic voltametric {E(1/2)(Cr(0/1+))}, (13)C NMR {δ((13)CN), δ((13)CO)}, UV-vis {dπ(Cr) → pπ*(CNAz) Metal-to-Ligand Charge Transfer}, and FTIR {ν(N)(≡)(C), ν(C)(≡)(O), k(C)(≡)(O)} analyses of the [(OC)(5)Cr(2-isocyano-1,3-X(2)-azulene)] complexes provided a multifaceted, quantitative assessment of the π-acceptor/σ-donor characteristics of the above five 2-isocyanoazulenes. In particular, the following inverse linear relationships were documented: δ((13)CO(trans)) vs. δ((13)CN), δ((13)CO(cis)) vs. δ((13)CN), and δ((13)CO(trans)) vs. k(C)(≡)(O,trans) force constant. Remarkably, the net electron withdrawing capability of the 2-isocyano-1,3-dicyanoazulene ligand rivals those of perfluorinated isocyanides CNC(6)F(5) and CNC(2)F(3). MDPI 2021-02-12 /pmc/articles/PMC7918097/ /pubmed/33673291 http://dx.doi.org/10.3390/molecules26040981 Text en © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Hart, Mason D.
Meyers, John J.
Wood, Zachary A.
Nakakita, Toshinori
Applegate, Jason C.
Erickson, Nathan R.
Gerasimchuk, Nikolay N.
Barybin, Mikhail V.
Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered
title Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered
title_full Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered
title_fullStr Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered
title_full_unstemmed Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered
title_short Tuning π-Acceptor/σ-Donor Ratio of the 2-Isocyanoazulene Ligand: Non-Fluorinated Rival of Pentafluorophenyl Isocyanide and Trifluorovinyl Isocyanide Discovered
title_sort tuning π-acceptor/σ-donor ratio of the 2-isocyanoazulene ligand: non-fluorinated rival of pentafluorophenyl isocyanide and trifluorovinyl isocyanide discovered
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918097/
https://www.ncbi.nlm.nih.gov/pubmed/33673291
http://dx.doi.org/10.3390/molecules26040981
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