Dataset Information

Control of dominant conduction orbitals by peripheral substituents in paddle-wheel diruthenium alkynyl molecular junctions.

ABSTRACT: Control of charge carriers that transport through the molecular junctions is essential for thermoelectric materials. In general, the charge carrier depends on the dominant conduction orbitals and is dominantly determined by the terminal anchor groups. The present study discloses the synthesis, physical properties in solution, and single-molecule conductance of paddle-wheel diruthenium complexes 1R having diarylformamidinato supporting ligands (DArF: p-R-C₆H₄-NCHN-C₆H₄-R-p) and two axial thioanisylethynyl conducting anchor groups, revealing unique substituent effects with respect to the conduction orbitals. The complexes 1R with a few different aryl substituents (R = OMe, H, Cl, and CF₃) were fully characterized by spectroscopic and crystallographic analyses. The single-molecule conductance determined by the scanning tunneling microscope break junction (STM-BJ) technique was in the 10^-5 to 10^-4 G ₀ region, and the order of conductance was 1OMe > 1CF3 ≫ 1H ∼ 1Cl, which was not consistent with the Hammett substituent constants σ of R. Cyclic voltammetry revealed the narrow HOMO-LUMO gaps of 1R originating from the diruthenium motif, as further supported by the DFT study. The DFT-NEGF analysis of this unique result revealed that the dominant conductance routes changed from HOMO conductance (for 1OMe) to LUMO conductance (for 1CF3). The drastic change in the conductance properties originates from the intrinsic narrow HOMO-LUMO gaps.

SUBMITTER: Ogawa S

PROVIDER: S-EPMC8372547 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The experimental electron-density distribution in two isostructural complexes, tetrakis(?2-acetato)diaquadicopper(II) [H2OCu(ac)2Cu(ac)2H2O] and tetrakis(?2-acetato)diaquadichromium(II) [H2OCr(ac)2Cr(ac)2H2O], has been studied and compared. The experimental electron density distribution in two isostructural and isomorphous complexes, tetrakis(?2-acetato)diaquadicopper(II) [H2OCu(ac)2Cu(ac)2H2O] (I) and tetrakis(?2-acetato)diaquadichromium(II), [H2OCr(ac)2Cr(ac)2H2O] (II), has been obtained from high-resolution X-ray diffraction data in order to shed light on the bonding properties in the compounds studied. It has been shown that from accurate X-ray data it is possible to discuss the bonding capability of the metal atom (Cu/Cr) and the ligands in these complexes. A comparison of results obtained from averaged and non-averaged X-ray data demonstrates that using the non-averaged data and introducing an anisotropic correction for secondary extinction errors provides a more detailed distribution of the electron density in the area of the metal atoms. In both complexes studied, the bonding of the acetate oxygen atom to the central metal atom is significantly affected by the formation of hydrogen bonds. The electron density and its Laplacian at the bond critical point of metal–oxygen coordination bonds for those oxygen atoms not involved in the intermolecular hydrogen bonds are approximately 10% larger compared with the case when oxygen atoms take part in hydrogen bonds with the neighboring water molecules. It is shown that metal–oxygen bonds in a quasi-equatorial plane are typical coordination bonds and differ significantly from the apical metal–oxygen bond. Metal–metal interaction with a small positive value of the electron density Laplacian at this bond critical point is mainly of electrostatic character. The metal–metal interaction is definitely not a bond according to the classical definition. Based on a search of the Cambridge Structural Database, it can be argued that there are four typical coordination bonds in the [CuO6] chromophore, similar to the four Cu—O coordination bonds in the basal plane of the CuO5 pyramid in one of the complexes under study.

Dataset Information

Control of dominant conduction orbitals by peripheral substituents in paddle-wheel diruthenium alkynyl molecular junctions.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets