Four‐Coordinate Copper Halonitrosyl {CuNO}10 Complexes

• Published in: Angewandte Chemie International Edition 2019-07, Vol.58 (30), p.10225-10229
• Main Authors: Bower, Jamey K., Sokolov, Alexander Yu, Zhang, Shiyu
• Format: Article
• Language: English
• Subjects: Alcohols; Amines; Chlorides; Coordination compounds; Copper; Copper compounds; Dichlorides; electronic structure; Nitric oxide; nitrite reduction; nitrosyl; Nucleophiles; reductive nitrosylation; Thiols; X-ray diffraction
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201904732

While copper nitrosyl complexes are implicated in numerous biological systems, isolable examples remain limited. In this report, we show that [Cl3CuNO]−, with a {CuNO}10 electron configuration, can be generated by nitrite reduction at a copper(I) dichloride anion or by nitric oxide addition to a copper(II) trichloride precursor. The bromide analogue, [Br3CuNO]− was synthesized analogously, and both copper halonitrosyl complexes were characterized by X‐ray diffraction and a variety of spectroscopic methods. Experimental data and multireference (CASSCF/NEVPT2) calculations provide strong evidence for a CuII–NO. ground state. Both [Cl3CuNO]− and [Br3CuNO]− release and recapture NO. reversibly, and exhibit nitrosative reactivities toward a wide range of biological nucleophiles, such as amines, alcohols, and thiols. A mystery NO more: For more than 100 years, copper halides have been known to absorb nitric oxide, but the structures of the products were never elucidated. Rare {CuNO}10 species that reversibly bind nitric oxide, TBA[Cl3CuNO] and TBA[Br3CuNO], have now prepared and structural characterized.