Syntheses and Properties of Triruthenium Polyhydrido Complexes Composed of 1,2,4-tri-tert-butylcyclopentadienyl and p-Cymene Ruthenium Units

Abstract

Mixed-ligand triruthenium hydrido complexes composed of [Cp‡Ru] (Cp‡ = 1,2,4-tri-tert-butylcyclopentadienyl) and [(p-cymene)­Ru] fragments, [(Cp‡Ru)2{(p-cymene)­Ru}­(μ-H)3(μ3-H)] (3a) and [(Cp‡Ru)­{(p-cymene)­Ru}2(μ-H)2(μ3-H)] (5), were synthesized. While the reaction of [(Cp*Ru)2(μ-H)4] (1a; Cp* = C5Me5) with 0.5 equiv of [(p-cymene)­RuCl2]2 in the presence of 2-propanol and a base did not afford 3a selectively, 5 was exclusively obtained by the reaction of [(Cp‡Ru)­{(p-cymene)­Ru}­(μ-H)3] (2a) with 0.5 equiv of [(p-cymene)­RuCl2]2. Both triruthenium complexes smoothly reacted with P­(OMe)3 to yield the corresponding phosphite adducts 7 and 8; however, the sites for P­(OMe)3 ligation were different in these complexes. While the P­(OMe)3 ligated at one of the [Cp‡Ru] sites in 3a, it ligated at the [(p-cymene)­Ru] site in 5. A quantum theory of an atoms in molecules analysis of these complexes revealed that a direct Ru–Ru interaction was present only at the (p-cymene)­Ru–Ru­(p-cymene) edges, which did not contain a μ-hydrido ligand. Due to the presence of the Ru–Ru bond, complex 5 showed high reactivity toward H/D exchange with deuterated benzene at 25 °C.

Machine learning-based screening of Mn-PNP catalysts for the CO2 reduction reaction using a region-wise ligand-encoded feature matrix

“…1b). 13,[36][37][38][39]42,43 The number of possible catalysts that came out from the considered ligands at the R 1 region with respect to each ligand present on the R 2 region is 330.…”

“…1c) are considered, respectively based on the experimental reports of PNP and other catalysts. 13,36–39 The P atom sites in the catalysts were found to be the most preferable sites for a variety of ligand substitutions and thus the number of considered ligands for the R 2 region is less compared to the R 1 region. 36–41 The PNP catalysts typically exhibit either complete symmetry with four identical ligand substituents across two P (L 1 = L 2 ) sites or a 1 : 1 ratio of two different ligands across both P sites (L 1 ≠ L 2 ) (Fig.…”

A Theoretical Investigation of Chemical Bonding of a Heterometallic Trinuclear Cluster Containing Iridium and Ruthenium: [(Cp*Ir) (CpRu)2 (μ3-H) (μ-H)3] by QTAIM Approach

“…These cluster complexes, which differ from mononuclear complexes in reactivity, can coordinate with substrate molecules many times and form a multi-electron transfer to the substrate 3,4 . In the polyhydrido clusters, the releasing of bridging hydrido ligands play an important spontaneously introducing multiple unoccupied coordination sites on the neighboring metal centers [5][6][7] . Based on the very high electron density at the transition metal atoms of the polyhydrido clusters having cyclopentadienyl ligands, Suzuki et al 8 argued that the reactivity was increased toward the splitting of inactive chemical bonds, such as the C−C and C−H bonds of alkanes.…”