Ruthenium‐Hydride Assisted Remarkable Diversity Towards Non‐Spectator Feature of Benzodifuroxan

Abstract

The present article demonstrates that rutheniumhydride [Ru II (H)(Cl)(CO)(PPh 3) 3 ] mediated diverse functionalization modes of benzodifuroxan (BDF) encompassing two furoxan rings. Hydride transfer from the metal precursor facilitated multiple cascade reactions involving unsymmetrical cleavage of the furoxan rings of BDF, leading to the onepot formation of a series of ruthenium (II) coordinated functionalized ligands exhibiting bidentate k 2-N,O, k 2-N,N' and bis-bidentate μ-bis(k 2-N,O) modes. Further, a moderately stable intermediate species was also encountered in the reaction sequence in which the transformed deoxygenated ligand coordinated to the metal ion via the rarely manifested furazan ring (k 2-N,N'' mode). The products were authenticated by their single-crystal X-ray structures and other spectroscopic/analytical techniques. Redox non-innocence of the functionalized ligands in the complexes was illustrated by spectroelectrochemistry (cyclic voltammmetry, UV-Vis. and EPR) in conjunction with DFT/TD-DFT calculations. Mechanistic outline for the facile ring opening processes of BDF including interconversions of complexes (e. g. reductive ring opening) were also addressed.

Ruthenium–Benzothiadiazole Building Block Derived Dynamic Heterometallic Ru–Ag Coordination Polymer and Its Enhanced Water-Splitting Feature

“…1 and 2 exhibited BTD-targeted mixed metal/ligand based MLCT (metal to ligand charge transfer) transitions in the visible region (800–500 nm) and interligand (acac to BTD)/intraligand (BTD to BTD) transitions in the higher-energy UV region. On the other hand, less intense visible bands of one-electron-oxidized ( 1 + / 2 + ) and -reduced ( 1 – / 2 – ) states corresponded to ruthenium-targeted mixed ligand/metal based LMCT (ligand to metal charge transfer) and BTD/acac-targeted mixed metal/ligand based MLCT transitions, reflecting the effect of covalency in the mixed metal/ligand transitions. , The polymeric complex 3 exhibited two moderately intense visible transitions at 575 and 398 nm along with intense bands in the UV region.…”

Redox-Induced Intramolecular C–C Coupling of Acyclic Bis(2-pyridylmethylene)ethylenediamine on a Ru(acac)2 Platform

“…The unperturbed feature of BPE in 1 was reflected well in its 1 H NMR profile (half-molecule): 4H (aromatic), 1H (NCH), and 2H (N–CH 2 ). The same BPE protons, however, partially merged with the clusters of peaks arising out of PPh 3 in 3 2+ . The methylene protons of BPE and BPE in 1 were also manifested by 13 C/DEPT-135 NMR (Figures S6 and S7).…”

“…In the absence of the crystal structure, the anti form of 1 could be justified by the structurally characterized BPE-bridged diruthenium complex [ 3 ]­(ClO 4 ) 2 (Figure and Tables S2–S4) as well as based on other reported analogous systems. ,, Coordination of the pyridyl and aldimine N donors of BPE to the Ru ions in [ 3 ]­(ClO 4 ) 2 extended anti -configured five-membered chelates with the bite angle of 75.51°. The Ru ion fitted well in the equatorial plane consisting of N1, H, C8, and N2 atoms, and the two trans -oriented PPh 3 groups led to the P–Ru–P angle of 164.35(3)° . The S - trans conformation of the aliphatic bridge (C7–C7 i ) of BPE oriented the almost parallel metal ions in the opposite direction with a Ru---Ru distance of 7.599 Å.…”

“…On the other hand, 3 2+ exhibited irreversible Ru II /Ru III oxidation at a very high potential of 1.41 V versus SCE primarily because of the impact of π-acidic CO and PPh 3 (Figure S17). It also displayed two quasi-reversible reductions of BPE.…”

“…The Ru ion fitted well in the equatorial plane consisting of N1, H, C8, and N2 atoms, and the two trans-oriented PPh 3 groups led to the P−Ru−P angle of 164.35(3)°. 19 The S-trans conformation of the aliphatic bridge (C7−C7 i ) of BPE oriented the almost parallel metal ions in the opposite direction with a Ru---Ru distance of 7.599 Å.…”