Structure and Electronic Properties of an Expanded Terpyridine Complex of Nickel(II) [Ni(ddpd)₂](BF₄)₂

Abstract

The synthesis, structure in the solid state, electrochemical, magnetic and optical properties of a new nickel(II) complex [Ni(ddpd)2]2+ bearing the tridentate N,N′‐dimethyl‐N,N′‐dipyridin‐2‐ylpyridine‐2,6‐diamine (ddpd) ligand are presented. The optical properties are discussed within the framework of ligand field theory.

Luminescence and Light‐Driven Energy and Electron Transfer from an Exceptionally Long‐Lived Excited State of a Non‐Innocent Chromium(III) Complex

“…Similar to the mainly meridionally coordinating tridentate ligand ddpd, the tripodal ligand 1,1,1‐tris(pyrid‐2‐yl)ethane (tpe) forms 6‐membered chelate rings with nearly 90° bite angles with transition metal complexes . Tetradentate tpe analogues were successfully employed in several MCl 2 (L) complexes .…”

Ddpd as Expanded Terpyridine: Dramatic Effects of Symmetry and Electronic Properties in First Row Transition Metal Complexes

“…The intensity of the spin-flip band is rather high due to an intensity borrowing mechanism, which scales directly with the square of the spin-orbit coupling parameter λ and inversely with the square of the energy difference ∆E ( Figure 5; shoulder at 11,300 cm -1 for [Ni(ddpd)2] 2+ ) [93]. The energy differences between the 1 E and 3 T2 spectroscopic terms are quite small and consequently luminescence from the spin-flip 1 E states is not observed [61]. species after ligand loss.…”

“…The UV/Vis/NIR absorption spectra of red [Ni(tpy)2] 2+ and pink [Ni(ddpd)2] 2+ are dominated by the two spin-allowed 3 A2 → 3 T1 and 3 A2 → 3 T2 ligand field transitions at 18,500/12,350 and 19,200/12,700 cm -1 , respectively ( Figure 5) [24,61,91]. The transitions at lowest energy correspond directly to the respective ligand field splittings ∆o = 12,350 and 12,700 cm −1 , demonstrating that ddpd induces a stronger ligand field by 350 cm −1 .…”

“…UV/Vis/NIR spectrum of [Ni(ddpd) 2 ][BF 4 ] 2 in CH 3 CN; ligand field bands and the spin-flip band indicated by blue arrows; photograph of crystals of [Ni(ddpd) 2 ][BF 4 ] 2[61].…”

Luminescence and Light‐Driven Energy and Electron Transfer from an Exceptionally Long‐Lived Excited State of a Non‐Innocent Chromium(III) Complex

“…[20,36,37] Af urther aspect is to reduce excited state distortion, especially large trigonal twists. [16,17] Similar to the mainly meridionally coordinating tridentate ligand ddpd, [3,6,[38][39][40][41][42][43] the tripodal ligand 1,1,1-tris(pyrid-2yl)ethane (tpe) [44] forms 6-membered chelate rings with nearly 908 8 bite angles with transition metal complexes. [45,46] Te tradentate tpe analogues [47] were successfully employed in several MCl 2 (L) complexes.…”