Ion Mobility Mass Spectrometry Uncovers Guest-Induced Distortions in a Supramolecular Organometallic Metallosquare

Abstract

The encapsulation of the tetracationic palladiummetallosquare with four pyrene-bis-imidazolylidene ligands[1]4+with aseries of organic molecules was studied byElectrosprayionization Travelling Wave Ion-Mobility MassSpectrometry (ESI TWIM-MS). The method allowed todetermine the Collision Cross Sections (CCSs), whichwereused to assess the sizechanges experienced by the host uponencapsulation of the guest molecules.When fullerenes wereused as guests,the host is expanded DCCS 13 2and 23 2,forC60or C70,respectively.The metallorectangle [1]4+was alsoused for the encapsulation of aseries of polycyclic aromatichydrocarbons (PAHs) and naphthalenetetracarboxylic diimide(NTCDI), to form complexes of formula [(NTCDI)2-(PAH)@1]4+.For these host:guest adducts,the ESI IM-MSstudies revealed that [1]4+is expanded by 47–49 2.. Theenergy-minimized structures of [1]4+,[C60@1]4+,[C70@1]4+,[(NTCDI)2(corannulene)@1]4+in the gas phase were obtainedby DFT calculations.Introduction