Synthesis, X-ray structural determination and biological evaluation of novel ferrocene grafted spiroquinoxalinopyrrolidine.

• Structurally intriguing novel spiroheterocyclic hybrid has been synthesized in excellent yield. • Spiroheterocycle has been achieved via one-pot [bmim]Br accelerated multicomponent green protocol. • The structure and stereochemistry of the compound elucidated by spectroscopic and X-ray analysis. • Molecular packing and interaction has been investigated by Hirshfeld and DFT calculations. • Food borne bacterial inhibitory activity observed. Synthesis of a hybrid heterocycle comprising ferrocene, spiropyrrolidine and quinoxaline structural moieties have been achieved in good yield via ionic liquid expedited multicomponent 1,3-dipolar cycloaddition reaction. Structural properties of the synthesized compound were exploited using single crystal X-ray crystallographic studies. Hirshfeld analysis revealed the importance of H...H (59.6%), C H...π (22.4%) and N...H (3.5%) contacts within the molecular packing. The Fe-C interactions around ferrocenyl moiety were investigated using Natural Bond Orbital (NBO) and Atoms In Molecules (AIM) calculations. A predominant covalent character of interactions between Fe-C were been accessed from AIM calculation. A weaker extend of π-back donation appeared in cyclopentadienyl moiety carrying the substituent instead of unsubstituted one. Further, the in vitro antimicrobial potential of the synthesized compound against five food borne bacterial pathogens reveals its significant activity against E. coli and S. enterica with MIC values 6.00 µg/mL and 8.00 µg/mL, respectively. The antioxidant activity of compound 5 was found to be 84.37±0.55 at 250 µg/mL concentration with an IC 50 value = 33.80 µg/mL. [ABSTRACT FROM AUTHOR]