Syntheses, Crystal Structures, and Spectral Properties of a Series of 3,8-Bisphenyl-1,10-phenanthroline Derivatives:  Precursors of 3,8-Bis(4-mercaptophenyl)-1,10-phenanthroline and Its Ruthenium(II) Complex for Preparing Nanocomposite Junctions with Gold Nanoparticles between 1 μm Gap Gold Electrodes

Abstract

A multistep synthesis was achieved to obtain 3,8-bis(4-mercaptophenyl)-1,10-phenanthroline, which has two free thiol end groups with a molecular length of 1.89 nm, and its ruthenium(II) complex. Five single-crystal structures and UV-vis spectra of related intermediates in methanol and the solid state were studied in order to obtain additional information on the molecules as well as on the supramolecular interactions in the structures. Thermal and electrochemical properties of related Ru(II) complexes were also involved. 3,8-Bis(4-mercaptophenyl)-1,10-phenanthroline and one of its ruthenium(II) complexes were then treated with gold nanoparticles (Au-NPs) via in situ thiol-to-thiol ligand exchange in the presence of two facing Au electrodes with a 1 x 1 microm(2) gap. Stable molecular junctions composed of self-assembled films were produced as revealed by an obvious increase of the conductivity between the Au electrodes, wherein dithiols-bridged Au-NPs were attached to the electrodes by means of Au-S-bonded contacts. Temperature-dependent current-voltage (I-V) measurements for the junctions were performed in the temperature range of 7-300 K, and classical Arrhenius plots and their linear fits were obtained to determine the average activation energies (DeltaE) of these devices. It is found that when the Ru(II) ion is introduced, the conductivity of the nanodevice is increased and the energy barrier is lowered under the same experimental conditions.

Properties of Thiol End‐Capped and Iodine‐Doped Sexithiophene Disulfide Semiconducting Polymers Bridging Nanogap Gold Electrodes

“…Fabricating nanodevices using Au-S bonds between the gold electrodes and the thiol end-capped organic molecules has been proven to be a good strategy to effectively reduce the interfacial barrier. [13][14][15][16][17] On the other hand, the relative conductance of oligothiophenes can be changed by oxidizing or reducing them, or introducing a dopant into the bulk because the oligothiophene proconductors can become oligothiopheniums, which are much better conductors because of the unfi lled HOMO and a change in geometry which creates mid-gap states. [ 18 ] Formation of the disulfi de bond is an effective way to extend the length of oligothiophenes.…”

Comparisons on isomeric 1,10-phenanthroline aromatic heterocyclic derivatives with triphenylamine and thiophene donors before and after rhenium(I) carbonyl complexation

“…17 In our previous work, a family of 3,8-disubstituted linear 15e,17def,18 and 5,6-fused planar 19 phen-based aromatic heterocyclic compounds with thiophene/oligothiophene, imidazole, pyridine, pyrazine and benzene groups and their transition-metal complexes have been studied, and some of them show temperature-dependent semiconducting and photoresponsive properties. 17d, 18 Recently, some linear bithiazole-centered aromatic heterocyclic compounds with electron-donating TPA and thiophene donors and their Re(I) complexes have been firstly described because of their adjustable electronic properties. 20 As an extensive study, we intend herein to introduce Re(I) ion into the phen-based aromatic heterocyclic ligands with TPA and thiophene donors at different substituted positions of phen.…”

Supramolecular frameworks composed of copper(II), zinc(II), and ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different molar ratios of metal and ligand

“…For example, extend heterocyclic aromatic compounds prepared from 3,8-disubstituted-1,10-phenanthroline halides having delocalized p-electrons are good candidates for the studies on electric conductors, organic light emitting diodes, and organic field effect transistors [13][14][15][16][17]. Like 1,10-phenanthroline, 1,10phenanthroline halides can also provide two nitrogen atoms to act as bidentate chelating ligands in the reactions with transition-metal cations exhibiting intriguing supramolecular architectures and network topologies [18][19][20][21].…”