Ru–NO and Ru–NO₂bonding linkage isomerism in cis-[Ru(NO)(NO)(bpy)₂]^2+/+complexes – a theoretical insight

Abstract

Ruthenium nitrosyl complexes have received considerable attention due to the fact that they are able to store, transfer and release NO in a controlled manner. It is well-known that the NO reactivity of ruthenium nitrosyl complexes can be modulated with the judicious choice of equatorial and axial ligands. In this piece of research we elucidate the nature of the Ru-NO and Ru-NO2 bonding in a cis-[Ru(NO)(NO2)(bpy)2](2+) complex energy decomposition (Su-Li EDA) and topological (e.g., QTAIM) and natural bond orbital analysis. It was observed that the strength of these bonds is directly correlated with the relative stability of isomers involved in nitro-nitrito and nitrosyl-isonitrosyl isomerism, as described previously by Coppens and Ooyama.

Ruthenium nitrosyl complexes containing pyridine-functionalized carbenes – A theoretical insight

“…We have already confirmed, by means of the energy decomposition analysis, the influence of different equatorial ligands, including tetraazamacrocycles [10] and tetraammines [12], on the electronic structure of the RueNO chemical bonding, and consequently on the lability of the RueNO bond. We have also investigated the RueNO bonding situation prior, {RuNO} 6 , and after the monoelectronic reduction, {RuNO} 7 , by considering different linkage isomers [8].…”

The versatile ruthenium(II/III) tetraazamacrocycle complexes and their nitrosyl derivatives

“…Theoretical calculations have been used to provide deep insight into fundamental properties, such as stretching frequencies and geometries, as well as excited or photo-induced metastable states, thereby elucidating Ru NO bonding modes and allowing prediction of the relative stability of light-induced linkage isomers [55][56][57][58][59][60][61][62][63][64][65]. Recently, energy decomposition analysis (EDA) has revealed the nature of the Ru NO bond in tetraazamacrocycle complexes, allowing investigation of the influence of ring-size and N-appended methyl groups both prior to and following one-electron reduction [56].…”

The influence of L ligands on the {RuNO}6/7 bonding situation in cis-[Ru(NO)(NO2)L1–4]q complexes: a theoretical insight

“…33,40 In a recent publication, it has been shown that the Ru-NO interaction in cis-[Ru(NO)(NO 2 )(bpy) 2 ] 2+ isomers is slightly affected by nitronitrito isomerism. 37,41 Computational studies about ruthenium nitrosyl complexes have contributed to elucidate the reactivity of NO, including its release/retention levels in vivo. 37,41 Computational studies about ruthenium nitrosyl complexes have contributed to elucidate the reactivity of NO, including its release/retention levels in vivo.…”

“…41 However, the relative stability of the Ru-NO interaction in {RuNO} 6 /{RuNO} 7 cores is extremely dependent on nitrosyl-isonitrosyl isomerism. 8,31,37,38,41 Lahiri and Kaim 42 have discussed in both experimental and theoretical means the electronic structure of {RuNO} 6 and {RuNO} 7 moieties. 8,31,37,38,41 Lahiri and Kaim 42 have discussed in both experimental and theoretical means the electronic structure of {RuNO} 6 and {RuNO} 7 moieties.…”