Bonding and Substituent Effects in Electron-Rich Mononuclear Ruthenium σ-Arylacetylides of the Formula [(η²-dppe)(η⁵-C₅Me₅)Ru(C⋮C)-1,4-(C₆H₄)X][PF₆]_n(n= 0, 1; X = NO₂, CN, F, H, OMe, NH₂)

Abstract

This study reports the isolation and the structural (X-ray), UV-vis, and NMR characterization of a series of electron-rich Ru(II) acetylide complexes of the formula (η 2 -dppe)(η 5 -C 5 Me 5 )Ru(CtC)-1,4-(C 6 H 4 )X (1a-f; X ) NO 2 , CN, F, H, OMe, NH 2 ) and (η 2 -dppe)(η 5 -C 5 Me 5 )Ru(CtC)-1,3-(C 6 H 4 )F (1c-m), as well as the spectroscopic (near-IR and ESR) in situ characterization of the corresponding elusive Ru(III) radical cations. The spectroscopic data are discussed in connection with DFT computations, and a consistent picture of the electronic structure of these Ru(II) and Ru(III) acetylide complexes is proposed. Notably, the strong reactivity of the Ru(III) radicals evidenced in this contribution constitutes a major difference with the relative stability of the known iron analogues.

Electron‐Rich Iron/Ruthenium Arylalkynyl Complexes for Third‐Order Nonlinear Optics: Redox‐Switching between Three States

“…[17a, 18] We have previously established that the electron-releasing power of the "A C H T U N G T R E N N U N G (h 2 -dppe) 2 RuCl" group was slightly larger than that of a methoxy group. [8] Based on the anisotropy (Table 4) bility of the "trans-(h 2 -dppe) 2 RuC CPh" fragment compares with that of the "trans-(h 2 -dppe) 2 RuCl" and "trans-(h 2 -dppe) 2 RuCC(4-C 6 H 4 NO 2 )" fragments, which fall, as expected, between those observed for mononuclear Fe III -arylacetylide complexes featuring methoxy (6-OMeA C H T U N G T R E N N U N G [PF 6 ]) and amino (6-NH 2 A C H T U N G T R E N N U N G [PF 6 ]) substituents (Scheme 6).…”

Some Ruthenium Derivatives of Penta-1,4-diyn-3-one

“…2.251 Å, P-Ru-P 83.21(2), P-Ru-C(1) 78.90, 89.79(7)º]. 36 The Ru-C(1) not characterized, but treated with NEt 3 in situ to ultimately give 2, likely through deprotonation of the vinylidene and reaction with a second molecule of 1, followed by loss of HCl and CO. Attempts to synthesise ({Cp(dppe)Ru}C≡C) 2 CO by an analogous route from Ru(C≡CH)(dppe)Cp and oxalyl dichloride afforded only [Ru(=C=CH 2 )(dppe)Cp] + , identified from its 1 H and 31 P NMR spectra, after workup.…”

The synthesis, molecular and electronic structure of cyanovinylidene complexes

“…[81]. In each case (3, 5) the metal centre is in a pseudooctahedral geometry, with the P(1)-Ru-P(2) bond angle ca.…”

“…The electrochemical response of ruthenium(II) acetylide complexes of general form Ru(CCAr)(PP)Cp' (Ar = aromatic substituent, PP = phosphine donors, Cp' = Cp, Cp*) is characterised by an oxidation event that has considerable ethynyl ligand character, and as such the potentials of these redox processes, and the chemical stability of the resulting radical cations, is sensitive to the nature of the aromatic group and the electronic properties of substituents [40,81]. However, the different combinations of solvent, supporting electrolyte, temperature and reference electrode employed in collecting the range of available data can make direct comparisons of the results collated from many different research groups difficult, especially in the absence of a reported potential for an internal reference compound [105].…”