Mechanistic Insights into the Chemistry of Ru(II) Complexes Containing Cl and DMSO Ligands

Abstract

Two new isomers trans,mer-[RuIICl2(bpea)(DMSO)], 2a, and cis,fac-[RuIICl2(bpea)(DMSO)], 2b, (bpea = N,N-bis(2-pyridylmethyl)ethylamine), as well as the bis-DMSO complex trans,fac-[RuIICl(bpea)(DMSO)2]Cl, 3, have been synthesized and characterized by cyclic voltammetry and UV-vis and 1D and 2D NMR spectroscopy in solution. Their solid-state structure has also been solved by means of single-crystal X-ray diffraction analysis. All the three complexes display a ruthenium metal center possessing a distorted-octahedral type of coordination, where the bpea ligand is coordinated in a meridional fashion in 2a and in a facial fashion in 2b and 3. The isomer 2a is the kinetically favored and thus can be thermally converted into 2b, that is the thermodynamically favored one. A thorough kinetic analysis strongly points toward a dissociative mechanism, where in the first step a chloro ligand is removed from the metal coordination sphere, followed by a geometric rearrangement before the chloro ligand coordinates again, generating the final complex. DFT calculations agree with the experimental data for the proposed mechanism and allow us to further characterize the mechanism of the 2a --> 2b rearrangement by obtaining the intermediates and transition state.

Mononuclear ruthenium compounds bearing N-donor and N-heterocyclic carbene ligands: structure and oxidative catalysis

“…4 for the 1b + case (see Figure S5e for the ROESY NMR spectra of the aromatic region of 1b + ) strong interactions were observed between the isopropyl group and H24, H27 and H28 of the trpy ligand as well as between the methyl group of the imidazole ring and H21 of the trpy ligand, which clearly allow the identification of the cis disposition of the 1b + complex. The same conclusion could be extracted from the ROESY NMR spectra of 1a + ( Figure S4e Concerning 5 + , due to the flexibility of the tridentate bpea ligand, able to potentially coordinate the Ru metal ion either facially or meridionally, 14 seven stereoisomers could be potentially formed when combining bpea with the non-symmetric bidentate CN ligand PhthaPz-OMe (Fig. 5).…”

The key role of coligands in novel ruthenium(II)-cyclopentadienyl bipyridine derivatives: Ranging from non-cytotoxic to highly cytotoxic compounds

“…Mononuclear complexes of the general formula [Ru( 5 The formulation and purity of all the new compounds is supported by analytical data, FT-IR spectroscopy, 1 H, 13 C, 31 [17][18][19][20]. The positive shift in the  S=O of ca.…”

Phosphine Ligand‐Free Ruthenium Complexes as Efficient Catalysts for the Synthesis of Quinolines and Pyridines by Acceptorless Dehydrogenative Coupling Reactions

“…As shown in Table S1 and S2 (in the Supporting Information), the RuÀ N (center pyridyl ring) bond length is shorter than other RuÀ N bond distances in all cases. The RuÀ Cl lengths in Ru(II) complexes range from 2.4217(13) Å to 2.4685(12) Å, which are longer than those in Ru(III) complexes ( (Table S1 and S2), which are shorter than those found in trans-[RuCl 2 (DMSO-kS)(terpy)] (terpy = 2,2' : 6',2''-terpyridine) (2.2734(10) Å), [86] trans,mer-[RuCl 2 (bpea)(DMSO-kS)] (bpea = N,N-bis-(2-pyridylmethyl)ethylamine) (2.2236(13) Å) [87] and cis,fac-[RuCl 2 (bpea)(DMSO-kS)] (2.2412(5) Å). [87] The N(5)À Ru (1)À N(1), Cl(2)À Ru(1)À Cl(3)/S(1), N(3)À Ru(1)À Cl(1) angles in 1 a·H 2 O-1b Me , 2 a-2b Me ·0.5H 2 O, N(10)À Ru(2)À N(6), Cl(5)À Ru(2)À Cl (6), N(8)À Ru(2)À Cl(4) angles in 1b Me and N(10)À Ru(2)À N(6), N (8)À Ru(2)À Cl(3), S(2)À Ru(2)À Cl(4) angles in 2b Me ·0.5H 2 O are in the range of 168.17(14)-178.66(5)°, indicating almost linear alignment (Table S1 and S2 in the Supporting Information).…”