Synthesis and characterization of Craig-type antiaromatic species with [4n+2] pi electrons

Chen, Lina1; Lin, Lu1,2; Nath, Amit Ranjan3,4; Zhu, Qin1; Chen, Zhixin1; Wu, Jingjing1,2; Wang, Hongjian1; Li, Qian1; Lin, Wen-Feng5; Zhu, Jun1,2; Xia, Haiping1,3,4

2023-02-07

10.1073/pnas.2215900120

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   Impact Factor & Quartile

0027-8424

1091-6490

Antiaromaticity is extended from aromaticity as a complement to describe the unsatu-rated cyclic molecules with antiaromatic destabilization. To prepare antiaromatic species is a particularly challenging goal in synthetic chemistry because of the thermodynamic instability of such molecules. Among that, both Huckel and Mobius antiaromatic spe-cies have been reported, whereas the Craig one has not been realized to date. Here, we report the first example of planar Craig antiaromatic species. Eight Craig antiaromatic compounds were synthesized by deprotonation-induced reduction process and were fully characterized as follows. Single-crystal X-ray crystallography showed that these complexes have planar structures composed of fused five-membered rings with clearly alternating carbon-carbon bond lengths. In addition, proton NMR (1H NMR) spec-troscopy in these structures showed distinctive upfield shifts of the proton peaks to the range of antiaromatic peripheral hydrogens. Experimental spectroscopy observations, along with density-functional theory (DFT) calculations, provided evidence for the Craig antiaromaticity of these complexes. Further study experimentally and theoretically revealed that the strong exothermicity of the acid-base neutralization process was the driving force for this challenging transformation forming Craig antiaromatic species. Our findings complete a full cycle of aromatic chemistry, opening an avenue for the development of new class of antiaromatic systems.

aromaticity Craig-type antiaromaticity deprotonation-induced reduction process driving force of aromaticity transformation

SCI

English

NI Journal Papers

Corresponding

National Natural Science Foundation of China["92156021","21873079","21931002"] ; Guangdong Provincial Key Laboratory of Catalysis[2020B121201002] ; UK EPSRC[EP/W03784X/1]

Science & Technology - Other Topics

Multidisciplinary Sciences

WOS:000929916300001

NATL ACAD SCIENCES

BIOLOGY & BIOCHEMISTRY;CLINICAL MEDICINE;MULTIDISCIPLINARY;PLANT & ANIMAL SCIENCE;ENVIRONMENT/ECOLOGY;SOCIAL SCIENCES, GENERAL;MICROBIOLOGY;ECONOMICS BUSINESS;IMMUNOLOGY;MATERIALS SCIENCE;MATHEMATICS;SPACE SCIENCE;MOLECULAR BIOLOGY & GENETICS;PHARMACOLOGY & TOXICOLOGY;CHEMISTRY;PSYCHIATRY/PSYCHOLOGY;NEUROSCIENCE & BEHAVIOR;PHYSICS;GEOSCIENCES;AGRICULTURAL SCIENCES;ENGINEERING

Web of Science

1.Xiamen Univ, Coll Chem & Chem Engn, Collaborat Innovat Ctr Chem Energy Mat, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China
2.Xiamen Univ, Coll Chem & Chem Engn, Fujian Prov Key Lab Theoret & Computat Chem, Xiamen 361005, Peoples R China
3.Southern Univ Sci & Technol, Shenzhen Grubbs Inst, Shenzhen 518005, Peoples R China
4.Southern Univ Sci & Technol, Dept Chem, Shenzhen 518005, Peoples R China
5.Loughborough Univ, Dept Chem Engn, Loughborough LE11 3TU, Leics, England

Chen, Lina,Lin, Lu,Nath, Amit Ranjan,et al. Synthesis and characterization of Craig-type antiaromatic species with [4n+2] pi electrons[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2023,120(6).

Chen, Lina.,Lin, Lu.,Nath, Amit Ranjan.,Zhu, Qin.,Chen, Zhixin.,...&Xia, Haiping.(2023).Synthesis and characterization of Craig-type antiaromatic species with [4n+2] pi electrons.PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,120(6).

Chen, Lina,et al."Synthesis and characterization of Craig-type antiaromatic species with [4n+2] pi electrons".PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 120.6(2023).