Abstract: In 2008, Albrecht and co-workers introduced a new member to the N-heterocyclic carbene (NHC) family, the ‘click’ derived 1,2,3-triazolylidenes (mesoionic carbenes, MICs).1 After that, 1,2,3-triazol-5-ylidenes have been well employed as attractive ligand motifs for accessing several transition-metal-based complexes with widespread applications in material chemistry and homogeneous catalysis.2 The main reasons behind these growing demands are their easy access via [3+2] Huisgen reaction between alkyne and azide and the stronger donor properties than their classical NHC-based counterparts.3 However, both the C4- and C5-unsubstituted 1,2,3-triazolium salts are not much utilized as MIC precursors by organometallic chemists, probably due to the availability of two backbone protons (C4- and C5-H), which possess narrow acidity difference and thus, reducing the selectivity during metalation.2,3 Nevertheless, our group has recently noticed that the regioselectivity at the 1,2,3-triazole backbone can be effectively achieved via sequential metalation generating several homo- and hetero-bimetallic complexes.4 Additionally, the simple ‘click’ derived 1,2,3-triazolium salts featuring two distinct coordination sites, one via oxidative addition and the other via classical deprotonation cum metalation, were designed and explored towards the synthesis of mono- and heterobimetallic complexes.5 In this seminar, we will also present the C-unsubstituted 1,2,3- and 1,2,4-triazolium-based heteroditopic ligand template and synthesis of various homobimetallic (comprising the same metal bound in chelated and non-chelated fashion) and hetero-bimetallic complexes. Along this direction, during the metalation of C-unsubstituted 1,2,3-triazolium salts via transmetalation, we observed the unprecedented phenomenon of 1,2 metal migration, generating rare and unique C4-coordinated RuII-complexes, by altering their reaction conditions. Finally, there will be a discussion on generating different C4-bound transition metal complexes by unique transmetallation procedure via the C4-bound RuII- pathway.
References:
1. P. Mathew P., A. Neels A., Albrecht M.; J. Am. Chem. Soc. 2008, 130, 13534-13535.
2. (a) Donnelly K. F., Petronilho A. Albrecht M.; Chem. Commun. 2013, 49, 1145-1159. (b) Schweinfurth D., Hettmanczyk L., Suntrup L., Sarkar B.; Z. Anorg. Allg. Chem. 2017, 643, 554-584.
3. Vivancos Á., Segarra C., Albrecht M.; Chem. Rev. 2018, 118, 9493-9586.
4. Illam P. M., Tiwari C. S., Rit A.; Chem. Sci. 2022, 13, 13387-13392.
5. Tiwari C. S., Illam P. M., Rit A.; Chem Asian J. 2023, 18, e202300484.