Structure, Spectra, and DFT Simulation of Nickel Benzazolate Complexes with Tris(2-aminoethyl)amine Ligand

Abstract

Benzazolate complexes of Ni(II), [Ni(pbz)(tren)]ClO (pbz = 2-(2'-hydroxyphenyl)-benzimidazole (pbm), 1, 2-(2'-hydroxyphenyl)-benzoxazole (pbx), 2, 2-(2'-hydroxyphenyl)-benzothiazole (pbt), 3; tren = tris(2-aminoethyl)amine), are prepared by self-assembly reaction and structurally characterized. Theoretical DFT simulations are carried out to reproduce the features of their crystal structures and their spectroscopic and photophysic properties. The three complexes are moderately luminescent at room temperature both in acetonitrile solution and in the solid state. The simulations indicate that the absorption spectrum is dominated by two well-defined transitions, and the electronic density concentrates in three MOs around the benzazole ligands. The Stokes shifts of the emission spectra of complexes 1-3 are determined by optimizing the electronic excited state.

Multielectron Chemistry within a Model Nickel Metalloprotein: Mechanistic Implications for Acetyl-CoA Synthase

“…TD-DFT calculations on geometry-optimized M121A Ni I –CO Az are in good agreement with these observations, predicting LMCT bands from S Cys to Ni at 30 300 and 24 956 cm –1 and an MLCT band from Ni to the carbon of CO at an intermediate energy of 28 540 cm –1 (Figure S5). The calculated transition energies of M121A Ni I –CO Az are within ∼1000 cm –1 of the experimental values, falling within a reasonable error for TD-DFT calculations on open-shell transition metal systems. − Given the size of the model, which contains ∼70 heavy atoms and approaches the limit of what, in our hands, is computationally accessible, this deviation between experiment and theory is considered acceptable. A larger computational model that includes additional secondary sphere interactions or calculations performed at a higher level of theory would be anticipated to result in greater agreement between the computational and experimental spectra.…”

Structural and spectroscopic characterization of a new luminescent NiII complex: bis{2,4-dichloro-6-[(2-hydroxypropyl)iminomethyl]phenolato-κ3 O,N,O′}nickel(II)

“…Zn II , Pd II , Pt II , Ir III and Re I complexes have been much more studied as luminescence emitters in comparison with Ni II Ni II complexes do not appear as numerously in the literature as emitter materials for OLEDs. However, some recent articles have evidenced an increasing interest for emitting Ni II complexes (Srinivas et al, 2016;Cerezo et al, 2017;More et al, 2017b). In the last decade, our research group and others have reported the synthesis, structural, spectroscopic, NLO and magnetic properties of some nickel(II) Schiff base complexes (Elerman et al, 2001;Kara et al, 2003;Ü nver et al, 2006;Shawish et al, 2016;Elmehdawi et al, 2017).…”

Phosphorescent Cyclometalated Iridium(III) Complexes Bearing Ethynyl‐Extended 2‐(2'‐Hydroxyphenyl) Benzoxazole Ancillary Ligands

“…[24,25] Alternatively, they are excellent chelates for a wide range of metallic or metalloid ions. [26][27][28] In this article, a series of cyclometalated iridium(III) complexes bearing a π-extended 2-(2-hydroxyphenyl) benzoxazole (HBO) ancillary ligand with terminal groups of different electronic nature (see Scheme 1) has been synthesized and their photophysical properties studied at room and low temperature. The nature of the transitions was probed in each case by TD-DFT calculations.…”

“…HBX heterocycles have been extensively used as highly emissive fluorophores due to a beneficial excited‐state intramolecular proton transfer (ESIPT) photophysical process, paving the way to many innovative applications , . Alternatively, they are excellent chelates for a wide range of metallic or metalloid ions …”