Spin‐Crossover Grafted Monolayer of a Co(II) Terpyridine Derivative Functionalized with Carboxylic Acid Groups

Abstract

AbstractThe synthesis and characterization of a new Co(II) spin‐crossover (SCO) complex based on 4′‐(4‐carboxyphenyl)−2,2′:6′,2″‐terpyridine ligand are reported. This complex can be successfully grafted on silver surface maintaining the SCO behavior. Thus, atomic force microscopy (AFM), matrix assisted laser desorption ionization – time‐of‐flight mass spectrometry (MALDI‐TOF MS), Raman spectroscopy, and XPS measurements, upon surface deposition, evidence the formation of a monolayer of intact molecules grafted through carboxylate groups to the Ag surface. Three different techniques: Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and X‐ray absorption spectroscopy (XAS), supported by first‐principles calculations, confirm that the deposited molecules undergo a gradual spin transition with temperature. This phenomenon is unprecedented for a monolayer of molecules directly grafted onto a metallic surface from solution.