Benzimidazol-2-ylidene ruthenium complexes for C-N bond formation through alcohol dehydrogenation

Authors

ZAHID NAWAZ
NEVİN GÜRBÜZ
MUHAMMED NAVEED ZAFAR
NAMIK ÖZDEMİR
BEKİR ÇETİNKAYA
İSMAİL ÖZDEMİR

Abstract

A low temperature hydrogen borrowing approach to generate secondary amines using benzimidazole-based N-heterocyclic carbene (BNHC) ruthenium complexes is reported. A series of the piano-stool complexes of the type [(η⁶ -p-cymene)(BNHC)RuCl2 ] (1a-g) were synthesized via one-pot reaction of the NHC salt precursor, Ag2 O, and [RuCl2 (p-cymene)]2 and characterized using conventional spectroscopic techniques. The geometry of two precursors, [(η⁶ -p-cymene)(Me4BnMe2 BNHCCH2OxMe)RuCl2 ] (1f) and [(η⁶ -p-cymene)(Me5BnMe2 BNHCCH2OxMe)RuCl2 ] (1g), was studied by single crystal X-ray diffraction. These catalysts were found to dehydrogenate alcohols efficiently at temperatures as low as 50 °C to allow Schiff-base condensation and subsequent imine hydrogenation to afford secondary amines. Notably, this ruthenium-based procedure enables the N-alkylation of aromatic and heteroaromatic primary amines with a wide range of primary alcohols in excellent yields of up to 98%. The present methodology is green and water is liberated as the sole byproduct.

DOI

10.55730/1300-0527.3606

Keywords

Benzimidazol-2-ylidenes, ruthenium complexes, amine alkylation, C-N bond formation, mild conditions

First Page

1209

Last Page

1223

Recommended Citation

NAWAZ, Z, GÜRBÜZ, N, ZAFAR, M. N, ÖZDEMİR, N, ÇETİNKAYA, B, & ÖZDEMİR, İ (2023). Benzimidazol-2-ylidene ruthenium complexes for C-N bond formation through alcohol dehydrogenation. Turkish Journal of Chemistry 47 (5): 1209-1223. https://doi.org/10.55730/1300-0527.3606