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

Abstract

The encapsulation of the tetracationic palladium metallosquare with four pyrene-bis-imidazolylidene ligands [1] 4+ with as eries of organic molecules was studied by Electrosprayi onization Travelling Wave Ion-Mobility Mass Spectrometry (ESI TWIM-MS). The method allowed to determine the Collision Cross Sections (CCSs), whichw ere used to assess the sizec hanges experienced by the host upon encapsulation of the guest molecules.W hen fullerenes were used as guests,the host is expanded DCCS 13 2 and 23 2 ,for C 60 or C 70 ,r espectively.T he metallorectangle [1] 4+ was also used for the encapsulation of as eries of polycyclic aromatic hydrocarbons (PAHs) and naphthalenetetracarboxylic diimide (NTCDI), to form complexes of formula [(NTCDI) 2 -(PAH)@1] 4+ .F or these host:guest adducts,t he ESI IM-MS studies revealed that [1] 4+ is expanded by 47-49 2 .. The energy-minimized structures of [1] 4+ ,[ C 60 @1] 4+ ,[ C 70 @1] 4+ , [(NTCDI) 2 (corannulene)@1] 4+ in the gas phase were obtained by DFT calculations.Introduction

Structural studies of supramolecular complexes and assemblies by ion mobility mass spectrometry

“…The relationship between the CCS of the macrocycle complex and CCS of the anion involved in the complex formation has been recently used to distinguish between conceivable complex conformations (Figure 21) (Zimnicka et al, 2021). Macrocycle 1 represents a sequentially The distortion of a host molecule upon ligand binding has also been recently observed by IM-MS for the encapsulation of the tetracationic palladium metallosquare, based on pyrene-bis-imidazolylidene ligands, with a series of organic molecules (Vincent et al, 2021). The IM-MS studies revealed that the encapsulation of helicene-based coordination cage [1] 4+ with guest molecules: (a) fullerenes (C 60 and C 70 ) and (b) threestacked heteroguests (Figure 22) leads to IM shifts towards higher values of arrival times of the supramolecular complex compared to the free host.…”