Xn:Harmful;69-72-7Relevant articles and documents
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Anschuetz
, p. 81 (1909)
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A functional model for quercetin 2,4-dioxygenase: Geometric and electronic structures and reactivity of a nickel(II) flavonolate complex
Jeong, Donghyun,Sun, Seungwon,Moon, Dohyun,Cho, Jaeheung
, (2021/10/27)
Quercetin 2,4-dioyxgenase (QueD) has been known to catalyze the oxygenative degradation of flavonoids and quercetin. Recent crystallographic study revealed a nickel ion occupies the active site as a co-factor to support O2 activation and catalysis. Herein, we report a nickel(II) flavonolate complex bearing a tridentate macrocyclic ligand, [NiII(Me3-TACN)(Fl)(NO3)](H2O) (1, Me3-TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane, Fl = 3-hydroxyflavone) as a functional model for QueD. The flavonolatonickel(II) complex was characterized by using spectrometric analysis including UV–vis spectroscopy, electrospray ionization mass spectrometer (ESI-MS), infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance spectroscopy (NMR). The single crystal X-ray structure of 1 shows two isomers with respect to the direction of a flavonolate ligand. Two isomers commonly are in the octahedral geometry with a bidentate of flavonolate and a monodentate of nitrate as well as a tridentate binding of Me3-TACN ligand. The spin state of 1 is determined to be a triplet state based on the Evans' method. Interestingly, electronic configuration of 1 from density functional theory (DFT) calculations revealed that the two singly occupied molecular orbitals (SOMOs) lie energetically lower than the highest (doubly) occupied molecular orbital (HOMO), that is so-called the SOMO-HOMO level inversion (SHI). The HOMO shows an electron density localized in the flavonolate ligand, indicating that flavonolate ligand is oxidized first rather than the nickel center. Thermal degradation of 1 resulted in the formation of benzoic acid and salicylic acid, which is attributed to the oxygenation of flavonolate of 1.
N,O-bidentate ligands-based salicylic spiroborates: A bright frontier of bioimaging
Belskaya, Nataliya P.,Benassi, Enrico,Fomin, Timur O.,Lugovik, Kseniya I.,Minin, Artem S.,Pozdina, Varvara A.,Shevyrin, Vadim A.
, (2022/02/25)
A new series of salicylic spiroborate complexes (SSBs) based on N,O-bidentate 2-(tert-cycloalkylamino)-5-(3-(arylamino)acryloyl)thiophene-3-carbonitriles (NO-SSBs) was obtained and characterized. The optical properties of these compounds were studied and compared with those of analogous BF2-based complexes. The geometries and electronic structures of the NO-SSBs in the ground and excited states, especially their key N–B–O link, were revealed using quantum chemical calculations and compared with the experimental data and photophysical characteristics. Hydrolytic dissociation and photodissociation were considered, and the effects of the NO-SSB structure and nature of the solvent on these reactions were established. Biological investigations elucidated the NO-SSBs ability to penetrate living and fixed cells and selectively accumulate in the endoplasmic reticulum (ER) and Golgi complex. Comparison of the NO-SSBs’ characteristics with those of a commercial dye demonstrated the superiority of their properties and prospects for application in the bio-visualization of the ER and Golgi complex.
