14384-45-3Relevant academic research and scientific papers
Tris-pyridylmethylamine (TPMA) complexes functionalized with persistent nitronyl nitroxide organic radicals
Badetti, Elena,Licini, Giulia,Lloveras, Vega,Scaramuzzo, Francesca Anna,Veciana, Jaume,Vidal-Gancedo, José,Wurst, Klaus,Zonta, Cristiano
, p. 10011 - 10016 (2020)
The chance to have persistent organic radicals in combination with metals has attracted much interest since it offers the possibility of having new functional molecules with multiple open-shell elements. In this study, we report the synthesis of two tripodal tris(2-pyridyl)methylamine ligands (TPMA) functionalized with nitronyl nitroxide persistent radicals. The newly formed ligands have been used to coordinate zinc(ii), copper(ii), iron(ii) and cobalt(ii). The resulting complexes have been investigated by means of electron paramagnetic resonance (EPR), ESI-MS, FT-IR spectroscopy and X-ray diffraction. An electron reduction of the N-O radical moiety has been observed, depending on the metal used for the formation of the complex and the reaction conditions. We have observed small differences in the EPR spectra depending on the meta or para position of the radical moiety in the complex structure and some antiferromagnetic interactions between the paramagnetic M(ii) ions and the radical species. This journal is
Revisiting the Ullman's Radical Chemistry for Phthalocyanine Derivatives
Fidan, Ismail,Luneau, Dominique,Ahsen, Vefa,Hirel, Catherine
, p. 5359 - 5365 (2018)
Phthalocyanine derivatives do not cease to gain attention due to their numerous properties and applications (e.g., sensor, PDT). This makes them a unique scaffold for the design of new material. In this context, we were interested to develop the synthesis of an imino nitroxide-substituted phthalocyanine by Ullman's procedure; a challenge due to the intrinsic low solubility of most phthalocyanine derivative in much solvents. To overcome this solubility problem, we designed a phthalocyanine with bulky neopentyl substituents in peripheral positions as counterpart to the imino nitroxide moieties. The imino nitroxide-substituted phthalocyanine was obtained by condensation of a monoformyl-substituted phthalocyanine with 2,3-bis(hydroxylamino)-2,3-dimethylbutane in refluxing THF–MeOH (2:1) mixture in the presence of p-toluenesulfonic acid monohydrate, follow by oxidation with PbO2. Characterization was performed by electrochemistry, UV/Vis and EPR spectroscopy in solution as well as SQUID in solid state.
Synthesis, crystal structures and magnetic properties of nitronyl nitroxide radical-coordinated copper(II) complexes
Gao, Yan-Li,Inoue, Katsuya
, p. 195 - 201 (2020)
The coordination compound constructed for nitronyl nitroxide radical NIT-Ph-4-Br and CuII(hfac)2(H2O)2 building blocks (NIT-Ph-4-Br = 2-(4-bromo-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, hfac = hexafluoroacetylacetonato) was successfully synthesized. The single-crystal X-ray diffraction analyses indicated that the complexes {(NIT-Ph-4-Br)2[Cu(hfac)2]3} have centrosymmetric five-spin structures consisting of three Cu(II) ions bridged by two nitroxide ligands and that they consist of two types of copper atoms, one with a heavily Jahn–Teller distorted (4 + 2) octahedral coordination (Cuoct) and hfac in trans-positions and the other with square pyramidal five-coordinated (Cupyr) with three hfac oxygen atoms and N–O oxygen atom at the base and the one hfac oxygen atom at the apex. Different geometries of the copper ions are quite important for magnetochemistry. The magnetic susceptibility study of the coordination compound shows strong antiferromagnetic interactions between the metal center and the organic radical.
High-Spin Organic Diradical with Robust Stability
Gallagher, Nolan M.,Bauer, Jackson J.,Pink, Maren,Rajca, Suchada,Rajca, Andrzej
, p. 9377 - 9380 (2016)
Triplet ground-state organic molecules are interesting with respect to several emerging technologies but typically exhibit limited stability. We report two organic diradicals, one of which possesses a triplet ground state (2J/kB = 234 ± 36 K) and robust stability at elevated temperatures. We are able to sublime this high-spin diradical under high vacuum at 140 °C with no significant decomposition.
Synthesis of vicinal bishydroxylamine
Ovcharenko,Fokin,Romanenko,Korobkov,Rey
, p. 1519 - 1525 (1999)
Reduction of 2,3-dimethyl-2,3-dinitrobutane with Zn in aqueous ethanol in the presence of NH4Cl affords 2,3-bis(hydroxylamino)-2,3-dimethylbutane together with 2,3-diamino-2,3-dimethylbutane and complex Zn salts. A modified procedure was developed for the synthesis of bishydroxylamine, which involves reduction in a Zn/NH4Cl/THF-H2O system.
Alkali metal ion triggered conductive and stimuli-responsive metallogels
Chen, Shaorui,Li, Xiaoyuan,Yu, Xudong
, (2021)
A novel gelator NDH containing naphthalimide substituted with a 4,4,5,5-tetramethylimidazoline-1,3-diol group was synthesized and characterized. Driven by dynamic coordination interactions between the imidazoline-1,3-diol unit and alkali, NDH self-assembled into a wide range of metallogels in pentanol triggered by sonication just at room temperature. The coordination interactions between NDH and Li+ were further certified by 1H NMR and XRD analysis. The gels were characterized by several experiments such as UV–vis, fluorescent, SEM and rheology experiments. Notably, the ion conductivity of Li+/metallogels confirmed that the three dimensional network in the organogels does not affect the ions diffusion in the large interconnected liquid domains. Electrochemical impedance spectroscopy was used to prove that NDH/LiClO4-gel had stronger electrical conductivity than that of NDH/LiCl-gel.
Synthesis, crystal structure, magnetic, spectroscopic, and theoretical investigations of two new nitronyl-nitroxide complexes
Spinu, Cristian Andrei,Pichon, Céline,Ionita, Gabriela,Mocanu, Teodora,Calancea, Sergiu,Raduca, Mihai,Sutter, Jean-Pascal,Hillebrand, Mihaela,Andruh, Marius
, p. 279 - 293 (2021)
Two mononuclear complexes [(Et3NH)[M(hfac)2L] (M = Ni, 1; Zn, 2) have been synthesized using a nitronyl-nitroxide radical substituted nitrophenol, that is 2-(2-hydroxy-3-methoxy-5-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-3-oxide-1-oxyl, HL, as a proligand. The crystal structures of 1 and 2 have been solved and indicate an octahedral coordination geometry of the metal ions. The magnetic behavior for 1 is characterized by a strong antiferromagnetic metal–radical interaction (J = ?351 ± 1 cm?1; H = ?JS Ni S Rad). This exchange interaction was rationalized by DFT calculations. The EPR spectra recorded in both solution and solid state at 120 K confirm the S = ? ground state for 1.
Tuning the sensitivity of fluorophore-nitroxide radicals
Borozdina, Yulia B.,Kamm, Valentin,Laquai, Frederic,Baumgarten, Martin
, p. 13260 - 13267 (2012)
The synthesis of pyrene-pyrazole nitronyl and imino nitroxides is reported, along with characterization of the radicals by UV-Vis, PL and EPR techniques. The UV-Vis studies revealed that the nature of the spacer attached to the nitroxide plays a crucial role in the radical n-π* transition intensity. This finding forms the basis for the evaluation of these nitroxides as redox-probes. The results of these investigations confirmed the preliminary assumptions of the profound sensing properties of these radicals. In fact, it was demonstrated that the sensitivity of the newly synthesized probes far surpasses known literature analogues. Hence, the strategy described here opens new horizons for the targeted design of radical sensing materials.
Synthesis and Straightforward Quantification Methods of Imino Nitroxide-Based Hexaradical Architecture on a Cyclotriphosphazene Scaffold
Fidan, Ismail,?nal, Emel,Yerli, Yusuf,Luneau, Dominique,Ahsen, Vefa,Hirel, Catherine
, p. 11447 - 11453 (2016)
The synthesis of a homogeneous neutral hexaradical architecture consisting of six imino nitroxide radical moieties covalently bonded on a cyclotriphosphazene scaffold was reported. The synthesis of hexaradical imino nitroxide compounds follows the Ullman procedure involving the condensation of 2,3-bis(hydroxylamino)-2,3-dimethylbutane with hexa-(4-formylphenoxy)cyclotriphosphazene (3) followed by oxidation of the condensation product hexa-[4-(1-hydroxy-4,4,5,5-tetramethyl-2-imidazoline-2-yl)phenoxy]cyclotriphosphazene (2) by NaIO4. Characterization of hexaradical was performed by X-ray and SQUID in solid state and by EPR, absorption spectroscopy, and electrochemistry in solution. CV of 1 shows an oxidation peak at 1.184 V (vs SCE) and a reduction peak at -0.883 V, both characteristics of the presence of phenyl imino nitroxide (7) moieties, suggesting that the contribution of the cyclotriphosphazene core is negligible. Attention was particularly focused on developing methods, UV-vis spectroscopy and square-wave voltammetry, to quantify the number of radicals in a way to confirm easily and rapidly the polyradicals' structure.
Synthesis, crystal structure, and magnetic properties of a nitronyl nitroxide biradical-coordinated copper(II) complex
Gao, Yan-Li,Gao, Pingqiang,Gong, Ying,Ren, Guoyu
, p. 590 - 595 (2021/01/04)
A coordination compound constructed from a nitronyl nitroxide biradical NITPh(3-NIT) and CuII(hfac)2(H2O)2 building blocks [NITPh(3-NIT) = 1,3-bis(1′-oxyl-3′-oxido-4′,4′, 5′, 5′-tetramethyl-4,5-dihydro-1H-imidazol-2-y1)-benzene, hfac = hexafluoroacetylacetonato] is successfully synthesized. The crystal structure is determined by X-ray single-crystal diffraction. The asymmetric complex {[(NITPh(3-NIT)]Cu(hfac)2} consists of one Cu(II) ion and two >N–O? groups and adopts a distorted triangular bipyramid with a penta-coordinated central copper(II) atom and three hfac oxygen atoms at the base and a >N–O? oxygen atom and one hfac oxygen atom at the apices. Intramolecular O..O bonding and π–π stacking interactions are observed between molecules. A magnetic susceptibility study of the coordination compound shows antiferromagnetic interactions between Cu(II) ions and >N–O? groups and very weak ferromagnetic interactions between Cu(II) ions and the free >N–O? group through O..O bonding between the nitroxide group oxygen atom and the oxygen atom of hfac.
