Diverse Multinuclear Alkali Metallated (Li, Na, K, Rb, Cs) Family of the 1,3,5-tris-2-aminopyridyl-2,4,6-triethylbenzene Framework

Literature on Group One organoelement chemistry is dominated by lithium, though sodium and potassium also feature prominently, whereas rubidium and caesium are rarely mentioned. With recent breakthroughs hinting that organoelement compounds of these two heavier metals can perform better than their lighter congeners in particular applications, important advantages could be missed unless complete sets of alkali metals are included in studies. Here, we report the synthesis and characterisation of a complete set of multi-alkali-metallated molecular compounds of the 1,3,5-tris[(4,6-dimethylpyridin-2-yl)aminomethyl]-2,4,6-triethylbenzene framework. Made by deprotonating the framework N-H bonds by a suitable base, the set comprises six THF-solvated compounds, four of which are homometallic, either containing Li in a trinuclear structure or Na, K, and Rb in hexanuclear structures. Since deprotonation was incomplete with Cs, its homometallic compound is tetranuclear containing two un-metallated N-H bonds. A heterobimetallic trilithium-tricaesium hexanuclear compound was also obtained by using a bimetallic Li-Cs base for deprotonation. Such alkali-metallated frameworks are often precursors to other multimetallic frameworks with unique properties across different fields of science.