Novel Polyaromatic-Terminated Transition Metal Complexes for the Functionalization of Carbon Surfaces

Abstract

In order to investigate the process of noncovalent adsorption on glassy carbon surfaces, two terpyridine ligands 4-pyren-1-yl-N-[5-([2,2';6',2'']terpyridin-4'-yloxy)-pentyl]-butyramide (tpy~py) and N-[5-([2,2';6',2'']terpyridin-4'-yloxy)-pentyl]-2-naphthamide (tpy~nap) as well as the homoleptic cobalt(II) complexes of these ligands (Co(tpy~py)(2)(PF(6))(2) and Co(tpy~nap)(2)(PF(6))(2)) were synthesized. Electrochemical measurements in solution were used to characterize the transport behavior of these complexes and to verify that the polyaromatic portion of each ligand did not dramatically influence the electronic properties of the transition metal complex. The adsorption of the cobalt complexes above on glassy carbon electrode surfaces was then examined using cyclic voltammetry and was found to be well described by Langmuir or Frumkin isotherms. The free energy of adsorption for Co(tpy~py)(2)(PF(6))(2) was considerably larger than that for Co(tpy~nap)(2)(PF(6))(2): -41 versus -30 kJ/mol.

Coordination chemistry on carbon surfaces

“…These observations are in accordance with some studies demonstrating that tripyrene complexes bind to graphene more strongly than mono-pyrene ones [168]. In spite of the increasing number of applications of -interactions for the immobilization of transition metal complexes, very little quantitative data are available apart from the works by Dichtel et al [169] who calculated from the adsorption isotherms of pyrene-tagged cobalt complexes on graphene a G ads = −0.404 eV and the one by Goldsmith et al [170] who evidenced that free energy of adsorption on glassy carbon electrode surfaces of cobalt complexes was larger for pyrene-tagged cobalt complexes than that for their naphthalene-tagged counterparts (−0.425 versus −0.311 eV).…”

“…Another reported strategy consists in the prior anchoring of a functionalized pyrene molecule, acting as a bridging unit, interacting with SWCNTs through the pyrene ring and strongly coordinating to the zinc center of the metallomacrocyle via a nitrogen atom of the functional group [163]. Apart from pyrene, that appears as a polyaromatic fragment of choice for the development of -interactions; other aromatic moieties like naphthalene [169,170,173], 1,10-phenanthroline [201][202][203] or even cyclopentadienyl (Cp) rings [204][205][206] have been successfully used for non-covalent immobilization of transition metal complexes onto graphitic surfaces and are presented in Table 12. Theoretical calculations using the surface integrated molecular orbital/molecular mechanics method were applied to the SWCNT/zirconocene system.…”

Electro- and Solar-Driven Fuel Synthesis with First Row Transition Metal Complexes

“…Pyrene groups interact more strongly with π-conjugated surfaces than smaller aromatic moieties such as anthracene or naphthalene. 603,606−614 Introduction of a pyrene anchor to a molecule of interest has been shown to allow immobilization of a wide range of hybrid structures, including redox probes, 614−617 molecular catalysts, 64,606−609 proteins, 618−621 and polyoxometalates. 622−624 Pyrene derivatization of a carbon surface provides stable anchorage, while also offering excellent control over the surface loading of the targeted molecular species by controlling the concentration of the pyrene-bearing compound in solution during the loading process.…”

Layer-by-layer self-assembly for controlled magnetic multilayer thin film fabrication

“…The inset shows the absorbance at 287 nm vs. the number of layers (A). ATR-IR spectra (from the upper to the lower curves) of PE-COOH having a clear carbonyl band at 1710 cm -1 and the multilayer film [P(mPhtpy-co-vbda)/Nd 3+ /Co 2+ ] n × 3 (n = 4, 8,12,16,20) being in the region from 700 to 4000 cm -1 (B). related to the terpyridinyl ring and carboxyl functional groups.…”

“…Their complexes exhibited distinct electrical (6), optical (7), magnetic (8) and catalytic (9) properties, giving them widespread applications in such fields as biomedical sciences (10), light-emitting electrochemical cells (LECs) (11), light-to-electricity conversion (12), etc. Furthermore, they have been used as basic components for fabricating selfassembled functional materials with nanostructures (e.g., based on gold, silver, CdS, TiO 2 , carbon nanotubes) (13)(14)(15)(16)(17) as well as surfaces (e.g., glass, gold, graphite) (18)(19)(20). With the development of supramolecular chemistry in recent years, the coordinative interaction between metal ions and terpyridinyl ligands has been applied to prepare well-designed supramolecular (co)polymers with various promising properties (21,22).…”