Functionalization of Oxide Surfaces by Terpyridine Phosphonate Ligands: Surface Reactions and Anchoring Geometry

Abstract

A strategy for creating a general-purposes surface functionalization platform is reported, based on direct attachment of phosphate groups onto hydroxylated surfaces and subsequent formation of a terpyridine-based monolayer. Such a platform is suitable for the construction, onto technologically relevant oxide surfaces, of single- and multilayer structures of interest in technological applications. In particular, the paper describes the successful attachment of 4-(2,2':6',2''-terpyridine-4-yl)benzenephosphonic acid (1, PPTP) onto a SiO(2) surface previously functionalized by means of Zr-phosphate groups. Two alternative anchoring strategies of the PPTP were explored: (i) a direct one-step way, implying no protection of terpyridinic functionality, and (ii) a three-step way, implying protection and successive deprotection of this group. It was found that, in the first case, the PPTP ligand anchoring to the Zr-containing phosphate layer takes place by means of terpyridinic group. At variance of this, in the second case, due to the protection of the terpyridinic functionality, the anchoring process takes place through the phosphonic group, making the terpyridinic moiety available for further reactions, i.e., multilayer constructs. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to study the functionalized surfaces, providing information on coverage, chemical structure, and stoichiometry of the various functionalized layers and, among the others, clear evidence of the PPTP linkage and orientation.

Terpyridine‐Functionalized Surfaces: Redox‐Active, Switchable, and Electroactive Nanoarchitecturesgland

“…In particular, the kinetically labile Zn II bis-terpyridine complexes, which are effi ciently reopened under acidic conditions, were demonstrated to be a new type of supramolecular "protecting group". The binding behavior of phosphonate-functionalized terpyridine 5 to metal-oxide-modifi ed surfaces was studied by Spampinato et al [ 38 ] For this purpose, a Zr IV phosphate monolayer on a SiO 2 substrate was prepared and served as a model substrate for any oxide surface capable of being hydroxylated. Due to the ambient binding ability of 5 , an unselective anchoring to the Zr IV ions was observed ( Figure 5 , route A); therefore, the "protecting group" approach ( Figure 5 , route B) was followed in which the Zn II bis-terpyridine complex [Zn( 5 ) 2 ]…”

A comprehensive study on the physicochemical and electrical properties of Si doped with the molecular doping method

“…In all these mentioned approaches, the deposition process is followed by a high temperature annealing step when the molecule decomposes and the dopant atoms diffuse from the surface into the substrate lattice. The substrate material frequently used as a target is Si [15][16][17][18][19][20][21], but InAs and InGaAs have been successfully doped too [12,22], together with oxidized silicon, alumina, and mica to study the molecule anchoring mechanisms [23,24]. The dopant atoms typically injected by the MD technique are phosphorus, boron, and sulfur.…”

Electrocatalytic CO2 Reduction with a Ruthenium Catalyst in Solution and on Nanocrystalline TiO2

“…Ru(PO 3 Et 2 -ph-tpy)Cl 3 was synthesized according to previously reported procedure. [37,38] Characterization 1 HNMR spectra were recorded on aB ruker Advance spectrometer at 400 MHz with CD 3 CN as the deuterated solvent. All proton chemical shifts (ppm) were referenced to the internal residual CH 3 CN signal (1.96 ppm) from the lock solvent.…”