Syntheses and characterizations of two-dimensional heteronuclear tetracyanonickelate(II) complexes with 4-ethylpyridine and investigation of the catalytic activity of [Cd(4epy)₂Ni(µ-CN)₄]_n

Abstract

Three new 2D heteronuclear tetracyanonickelate(II) complexes with 4-ethylpyridine (4epy), [Cu(4epy)₂Ni(µ-CN)₄]_n (1), [Zn(4epy)₂Ni(µ-CN)₄]_n (2) and [Cd(4epy)₂Ni(µ-CN)₄]_n (3), were synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, elemental and thermal analyses, single crystal (SC-XRD) and powder X-ray diffraction (PXRD) techniques. The single crystal X-ray analysis reveals that each metal ion (Cu(II), Zn(II), and Cd(II)) is coordinated by two nitrogen atoms from 4epy ligands and four nitrogen atoms from cyanide ligands and Ni(II) ions are coordinated by four carbon atoms from cyanide ligands showing a distorted octahedral and square planar coordination geometries, respectively. The most outstanding features of the complexes are the weak intermolecular C–H⋅⋅⋅Ni interactions between the Ni(II) ion and hydrogen atom of the ethyl group of the 4epy ligand. Adjacent 2D structures are further combined by these C–H⋅⋅⋅Ni interactions, generating a 3D network. The heterogeneous catalytic activity of 3 was investigated for oxidation of some primary and secondary aliphatic or aromatic alcohols; no acid formation was observed in some aromatic alcohols after 24 h and 100% aldehyde selectivity was determined.

KEYWORDS:

• Heteronuclear complexes
• tetracyanonickelate(II) complexes
• 4-ethylpyridine complexes
• 2D complexes
• C–H⋅⋅⋅Ni interaction

Acknowledgment

The authors acknowledge Scientific and Technological Research Application and Research Center, Sinop University, Turkey, for the use of the Bruker D8 QUEST diffractometer.

Supplementary material

Crystallographic data for the structural analysis have been deposited with the Cambridge Crystallographic Data Centre, CCDC No. 2207223 for 1, 2207222 for 2, and 2207221 for 3. Copies of this information may be obtained free of charge from the Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (Fax: [phone]; E-mail: [email protected] or www: http://www.ccdc.cam.ac.uk).

Author contributions

All authors share equally in writing the main manuscript and preparing the figures and the tables.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been financially supported by Eskişehir Osmangazi University, Scientific Research Unit (Grant No.: 2022-2561).