Investigation of syntheses, structures, theoretical calculations, and fluorescence properties of two N₃O-donor half-salamo-type Cu(II) complexes

Abstract

The coordination behaviors of asymmetric quinoline-decorated half-salamo-type ligand HL¹ with Cu(NO₃)₂·3H₂O and Cu(OAc)₂·H₂O were studied. Two Cu(II) complexes, [Cu(L¹)(NO₃)]·CH₃CH₂OH (1) and [Cu₂(L²)₂] (2), were isolated and characterized by X-ray crystallography, FTIR, UV–vis, and fluorescence spectroscopies. Structural analyses showed that 1 is a mononuclear species, whereas 2 is a binuclear entity. Spontaneous cleavage along the oxime N-O bond close to quinoline ring of the ligand HL¹ occurred upon reaction with Cu(OAc)₂·H₂O, yielding an unexpected complex 2. Moreover, DFT theoretical calculations and Hirshfeld surfaces analyses of the ligand HL¹ and its corresponding Cu(II) complexes were investigated in detail.

Graphical abstract

Keywords:

• Half-salamo-type ligand
• cleavage
• Cu(II) complex
• crystal structure
• Hirshfeld surface analysis

Supplementary data

CCDC-2166428 and 2166427 contain the supplementary crystallographic data for 1 and 2, respectively. These data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK (Telephone: [phone]; Fax: [phone]; or E-mail: deposit @ccdc.cam.ac.uk).

Conflicts of interest

The authors declare no competing financial interests.

Additional information

Funding

This work was supported by Gansu Science and Technology Planning Program (No. 20JR2RA002), the Open Foundation of Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou Jiaotong University (No. 21YRWEK004) and Department of Education of Gansu Province “Innovation star” of excellent Postgraduates (No. 2022CXZX-511), three of which are gratefully acknowledged.