The isomer-sensitive electrochemical HER of ruthenium(ii)–hydrido complexes involving redox-active azoheteroaromatics

Abstract

The article dealt with the development of isomeric ruthenium(II)-hydrido complexes [RuII(H) (L1)(PPh3)2(CO)]ClO4 ([1a]ClO4-[1b]ClO4) / [RuII(H)(L2)(PPh3)2(CO)]ClO4 ([2a]ClO4-[2b]ClO4) involving azo coupled L1 [L1: (E)-1,2-Bis(1-methyl-1H-pyrazol-3-yl)diazene] / L2 [L2: (E)-1,2-Bis(4-iodo-1-methyl-1H-pyrazol-3-yl)diazene)], respectively. Structural evaluation of...

Diverse Coordination Modes and Bidirectional Noninnocence of Pyridyl-β-diketonate on Ruthenium Platforms as a Function of Coligands

“…The average Ru III –O­(acac) (1.999 Å), ,, Ru II –N­(bpy) (2.043 Å), , Ru II –N­(pap) (1.999/2.031/2.020 Å), and Ru II –P­(PPh 3 )/Ru II –C­(CO) (2.352/1.816–2.347/1.813) ,,, in [ 1 ]­ClO 4 , [ 2 ]­ClO 4 , [ 3 ]­ClO 4 /[ 4 ]­ClO 4 /[ 5 ]­(ClO 4 ) 3 , and [ 7 ]­ClO 4 –[ 8 ]­ClO 4 , respectively, matched well with those reported for the analogous complexes.…”

“…Similar chemical shift values of severely overlapping aromatic proton resonances (Figures S9–S12 in the Supporting Information) are restricted to assigning their correspondences to the individual protons. ,,, Aromatic protons of PPh 3 and L – were well separated in mononuclear 6 , but the same were partially merged in dinuclear [ 7 ]­ClO 4 –[ 8 ]­ClO 4 . The Ru–H resonances in [ 7 ]­ClO 4 –[ 8 ]­ClO 4 displayed one and two triplets at δ, −14.9 and −9.88/–9.96 ppm due to its coupling with the nearby two symmetric and unsymmetric PPh 3 groups ( 31 P, I = 1/2), respectively. , One and two sharp 31 P NMR singlet(s) were resolved for 6/ [ 7 ]­ClO 4 and [ 8 ]­ClO 4 at δ, 32/44 ppm and 45 and 40 ppm (Figure S13 in the Supporting Information) due to the effect of magnetically equivalent and inequivalent two sets of trans -PPh 3 groups, respectively. The reasonably upfield shifted 31 P signal in Ru–Cl-bound 6 (δ, 30 ppm) with regard to the Ru–H-bound [ 7 ]­ClO 4 /[ 8 ]­ClO 4 (δ, 42–46 ppm) was also reflected in the corresponding Ru–P bond distances (Table ).…”

“…The reasonably upfield shifted 31 P signal in Ru–Cl-bound 6 (δ, 30 ppm) with regard to the Ru–H-bound [ 7 ]­ClO 4 /[ 8 ]­ClO 4 (δ, 42–46 ppm) was also reflected in the corresponding Ru–P bond distances (Table ). , The ν­(CO)/H and ν­(ClO 4 ) bands of the complexes appeared at ≈1940 and ≈1100 cm –1 , respectively (Experimental Section and Figure S14 in the Supporting Information).…”

Fine Tuning between Radical versus Nonradical States of Azoheteroarenes on Selective Osmium Platforms

“…On the other hand, our recent assessment of the analogous azoheteroarenes such as 2,2′-azobis­(benzothiazole) (abbt) and ( E )-1,2-bis­(1-methyl-1 H -pyrazole-3-yl)­diazene (bmpd) (Scheme ) on the selective ruthenium platforms facilitates the generation of all the three redox states of the azo function, neutral (NN 0 ), radical (N–N •– ), and dianionic (N–N 2– ) (Scheme ), via single-step IET or by the involvement of the metal-hydride/solvent as a redox equivalent and two-step IET, respectively . Further, Ru-abbt/Ru-bmpd derivatives also exhibit OER (oxygen evolution reaction) and HER (hydrogen evolution reaction) activities, respectively …”