Evidence for Bidirectional Noninnocent Behavior of
a Formazanate Ligand in Ruthenium Complexes
Abhishek Mandal
Brigitte Schwederski
Jan Fiedler
Wolfgang Kaim
Goutam Kumar Lahiri
10.1021/acs.inorgchem.5b01408.s004
https://acs.figshare.com/articles/journal_contribution/Evidence_for_Bidirectional_Noninnocent_Behavior_of_a_Formazanate_Ligand_in_Ruthenium_Complexes/2202019
Redox series of the complexes [Ru(L)(L′)<sub>2</sub>]<sup><i>n</i></sup>, L = 1,5-diphenyl-3-(4-tolyl)-formazanate
and L′ = 2,4-pentanedionate (acac<sup>–</sup>), 2,2′-bipyridine
(bpy), or 2-phenylazopyridine (pap), were studied by cyclic and differential
pulse voltammetry and by TD-DFT-supported spectroelectrochemistry
(UV–vis–NIR, EPR). The precursors [Ru<sup>III</sup>(L<sup>–</sup>)(acac<sup>–</sup>)<sub>2</sub>], [Ru<sup>II</sup>(L<sup>–</sup>)(bpy)<sub>2</sub>]ClO<sub>4</sub>, and [Ru<sup>II</sup>(L<sup>–</sup>)(pap)<sub>2</sub>]ClO<sub>4</sub> were
identified in their indicated oxidation states by X-ray crystal structure
determination. The six-membered formazanato-ruthenium chelate rings
have an envelope conformation with puckering of the metal. DFT calculations
indicate a pronounced sensitivity of the N–N bond lengths toward
the ligand oxidation state. Several electrochemically accessible charge
states were analyzed, and the derived oxidation numbers Ru<sup>II</sup>, Ru<sup>III</sup>, or Ru<sup>IV</sup>, L′ or (L′)<sup>•–</sup>, and L<sup>–</sup>, L<sup>•2–</sup>, or the new formazanyl ligand L<sup>•</sup> for the two-way
noninnocent formazanate reflect the increasing acceptor effect of
the ancillary ligands L′ in the series acac<sup>–</sup> < bpy < pap.
2015-08-17 00:00:00
EPR
oxidation numbers RuII
acac
acceptor effect
bpy
UV
Bidirectional Noninnocent Behavior
oxidation states
noninnocent formazanate
Ruthenium ComplexesRedox series
Formazanate Ligand
Several electrochemically
pap
envelope conformation
DFT calculations
RuIII
charge states
pulse voltammetry
ligand oxidation state