Twelve-membered B2Si4O6 borasiloxane macrocycles

•12-Membered ring is a missing link in borasiloxane ring systems.•1–3 are stable in solution, hence can be used in host guest chemistry.•1–3 can act as novel macrocyclic ligand systems to metal ions.•Opens up new avenue in coordination chemistry as 1–3 can act as sensors to metals.

A one pot three component reaction of boric acid, diphenylsilanediol and functionalized alcoholic pyrazole in 1:1:1 stoichiometry using toluene as a solvent under reflux conditions afforded twelve-membered borasiloxane macrocycle [(Ph2Si)4(O)6(BR1PzR)2] {R1 = C6H4OH and R = H for 1, R1 = C6H4OH and R = CH3 for 2 R1 = C10H6OH and R = H for 3} in moderate yields. Single crystal X-ray elucidation revealed the formation of a puckered twelve-membered ring system. ESI-MS studies indicate the stability of these macrocyclic systems in solution.

Graphical abstractA one pot three component reaction of boric acid, diphenylsilanediol and alcoholic pyrazole in 1:1:1 stoichiometry afforded twelve-membered borasiloxane macrocycle [(Ph2Si)4(O)6(BR1PzR)2] in moderate yields. Single crystal X-ray elucidation revealed the formation of puckered twelve-membered ring system. ESI-MS studies indicate the stability of these macrocyclic systems in solution.Figure optionsDownload full-size imageDownload as PowerPoint slide