Topological Analysis of Ag-Ag and Ag-N Interactions in Silver Amidinate Precursor Complexes of Silver Nanoparticles.

A series of silver amidinate complexes has been studied both experimentally and theoretically, in order to investigate the role of the precursor complex in the control of the synthesis of silver nanoparticles via an organometallic route. The replacement of the methyl substituent of the central carbon atom of the amidinate anion by a n-butyl group allows for the crystallization of the tetranuclear silver amidinate complex 3 instead of a mixture of di- and trinuclear silver amidinate complexes 1 and 2, as obtained with a methyl substituent. The relative stabilities and dissociation schemes of various isomeric arrangements of silver atoms in 3 are investigated at the computational DFT level of calculation, depending on the substituents of the amidinate ligand. The tetranuclear silver amidinate complex 4, exhibiting a diamondlike arrangement of the four silver atoms, is also considered. Ag-N bonds and argentophilic Ag-Ag interactions are finely characterized using ELF and QTAIM topological analyses and compared over the series of the related di-, tri-, and tetranuclear silver amidinate complexes 1-4. In contrast to the Ag-N dative bonds very similar over the series, argentophilic Ag-Ag interactions of various strengths and covalence degree are characterized for complexes 1-4. This gives insight into the role of the amidinate substituents on the nuclearity and intramolecular chemical bonding of the silver amidinate precursors, required for the synthesis of dedicated AgNPs with chemically well defined surfaces.

Phosphoryl group as a strong σ-donor anionic phosphine-type ligand: a combined experimental and theoretical study on long-lived room temperature luminescence of the [Ru(tpy)(bpy)(Ph2PO)]+ complex.

A phosphoryl Ru(II) polypyridyl complex was prepared in a one-pot process. Theoretical analysis suggests that the phosphoryl ligand may be viewed as a strong σ-donor anionic phosphine L-type ligand. State-of-the-art free-energy profile calculations on the excited states demonstrate that both favorable thermodynamic and kinetic factors are responsible for the remarkable room temperature luminescence properties of the phosphoryl complex.

Can a functionalized phosphine ligand promote room temperature luminescence of the [Ru(bpy)(tpy)]2+ core?

Unexpected room temperature luminescence is observed and rationalized by highly challenging excited state calculations for a functionalized phosphine ligand coordinated on the [Ru(bpy)(tpy)](2+) core.

Theoretical investigation on the photophysical properties of model ruthenium complexes with diazabutadiene ligands [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3).

In this study we report a theoretical comparative study of some photophysical properties in the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 0-3) series. Density functional theory calculations, validated by highly correlated ab initio benchmark calculations, were used to investigate the absorption and emission properties of the complexes with x = 1-3. The presence of a 1,4-diaza-1,3-butadiene (dab) ligand dramatically changes these properties because of the strong π-acceptor character of this ligand. As a result, comparing to the reference [Ru(bpy)(3)](2+) complex previously studied, we observed (i) a strong red-shift of the maximum of the absorption band, (ii) a strong decrease of the emission energy of the lowest triplet metal-to-ligand charge transfer state, with all the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3) complexes luminescent in the near-infrared region, while [Ru(bpy)(3)](2+) emits in the visible region, and (iii) the triplet metal-centered states become inaccessible in all the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3) complexes. Consequently, these complexes could be potential candidates for infrared light-emitting diodes and probes.

Luminescent ruthenium-polypyridine complexes & phosphorus ligands: anything but a simple story.

This tutorial review presents an exhaustive picture of the luminescence studies that have been undertaken on ruthenium(ii) complexes bearing polypyridine and phosphorus(iii) ligands. The introduction of phosphorus to the Ru coordination sphere has multiple consequences on the nature and energy of the various excited states involved, but it does not necessarily rule out room temperature emission.

Broad HOMO-LUMO gap tuning through the coordination of a single phosphine, aminophosphine or phosphite onto a Ru(tpy)(bpy)2+ core.

The synthesis of new ruthenium(II) terpyridine bipyridine complexes bearing a phosphorus(III) ligand is presented. The steric and electronic properties of the phosphorus ligand were varied using aminophosphines, alkyl and aryl phosphites and the bulky tri(isopropyl)phosphine. All complexes were characterized by multi-nuclear NMR spectroscopy, mass spectrometry and X-ray diffraction analysis. The electronic properties of the complexes were probed by cyclic voltammetry, absorption and luminescence spectroscopy. The complexes do not show luminescence at room temperature, whereas at 77 K in an alcoholic matrix, emission is observed in the range 600-650 nm with lifetimes of 3.5-5.5 micros, originating from 3MLCT states. The MLCT transition spans over 65 nm, which corresponds to a variation of 0.4 eV in the HOMO-LUMO gap. The oxidation potential of the ruthenium varies over a broad range of 290 mV, from +1.32 V vs. SCE with L = PiPr3 to +1.61 V vs. SCE with L = P(OPh)3. This range is unprecedented upon the variation of a single monodentate ligand coordinated by the same heteroatom in the same oxidation and charge states. This work underlines the specific capacity of phosphorus in bringing up a large variety of electronic properties by changing its substituents.