Search results for "Diimine"
showing 10 items of 32 documents
Mechanismus der Umsetzung von 1,1-Diphenylhydrazin mit Azodicarbonsäure-diethylester
1979
Bei der Umsetzung von 1,1-Diphenylhydrazin (1a) mit Azodicarbonsaure-diethylester (2a) uber-lagern sich funf Reaktionsmechanismen: A und B) Oxidation des Diphenylhydrazins 1a durch den Azodicarbonsaureester 2a zum Aminonitren 8; Bildung des Tetrazens 10 entweder durch Dimerisierung von 8 oder uber das Tetrazan 11; Zerfall von 11 in N2 und Diphenylamin. — C) Addition des Aminonitrens 8 an den Azodicarbonsaureester 2a zum Aminoazimin 3a; Zerfall von 3a in das Urethan 4a und den Azidoameisensaureester 5a. — D) Isomerisierung des Aminoazimins 3a zu 13 und Reduktion von 13 durch 1a zum Tetrazen 14; Spaltung von 14 in Diphenylamin und das Azid 15; Zerfall von 15 in Ethylcyanat (17) und den Kohlen…
Electro- and Photo-driven Reduction of CO 2 by a trans -(Cl)-[Os(diimine)(CO) 2 Cl 2 ] Precursor Catalyst: Influence of the Diimine Substituent and A…
2016
A series of [OsII(NN)(CO)2Cl2] complexes where NN is a 2,2′-bipyridine ligand substituted in the 4,4′ positions by H (C1), CH3 (C2), C(CH3)3 (C3), or C(O)OCH(CH3)2 (C4) has been studied as catalysts for the reduction of CO2. Electrocatalysis shows that the selectivity of the reaction can be switched toward the production of CO or HCOO− with an electron-donating (C2, C3) or -withdrawing (C4) substituent, respectively. The electrocatalytic process is a result of the formation of an Os0-bonded polymer, which was characterized by electrochemistry, UV/Visible and EPR spectroscopies. Photolysis of the complexes under CO2 in DMF+TEOA produces CO as a major product with a remarkably stable turnover…
Assembly and encapsulation of coordination tectons driven by hydrogen-bondingand space-filling
2001
[FR] Le composé ¿Fe(LI)3¿2¿Fe(H2O)6¿(ClO4)6 (2), LI = 1,10-phénanthroline-5,6-dione, a été synthétisé et caractérisé. La structure cristalline 2 est définie par un assemblage bidimensionnel non covalent, peu commun, constitué par des tectons chiraux ¿Fe(LI)3¿2+, assemblés par des cations ¿Fe(H2O)6¿2+ encapsulés dans des cages. Ces cages sont formées par 12 liaisons hydrogène établies entre les molécules d¿eau coordinées et les groupes dione appartenant à six molecules chirales ¿Fe(LI)3¿2+ ¿, ¿ alternées.
Magnetic coupling and spin topology in linear oxalato-bridged tetranuclear chromium(III)–copper(II) complexes with aromatic diimine ligands
2013
Abstract A novel heterotetranuclear chromium(III)–copper(II) complex of formula {[CrIII(bpy)(ox)2]2CuII2(bpy)2(ox)}·6H2O (1) has been synthesized by the ligand exchange reaction between Ph4P[CrIII(bpy)(ox)2]·H2O and [CuII(bpy)2(NO3)]NO3·MeOH in methanol (bpy = 2,2′-bipyridine; ox2− = oxalate dianion). The X-ray crystal structure of 1 consists of neutral oxalato-bridged CrIII2Cu2II zigzag entities which are formed by the monodentate coordination of two [CrIII(bpy)(ox)2]− mononuclear anionic units through one of its two oxalato groups toward a [CuII2(bpy)2(ox)]2+ dinuclear cationic moiety featuring relatively long axial bonds at the square pyramidal CuII ions. Variable temperature (2.0–300 K)…
Pulsed-current versus constant-voltage light-emitting electrochemical cells with trifluoromethyl-substituted cationic iridium(iii) complexes
2013
We report on five cationic iridium(III) complexes with cyclometalating 2-(3′-trifluoromethylphenyl)pyridine and a diimine, [(C⁁N)2Ir(N⁁N)](PF6), N⁁N = 4,4′-R2-2,2′-dipyridyl or 4,7-R2-1,10-phenanthroline (R = H, Me, tert-Bu, Ph), and characterize three of them by crystal structure analysis. The complexes undergo oxidation of the Ir–aryl fragment at 1.13–1.16 V (against ferrocene couple) and reduction of the N⁁N ligand at −1.66 V to −1.86 V, and have a redox gap of 2.84–2.99 V. The complexes exhibit bluish-green to green-yellow phosphorescence in an argon-saturated dichloromethane solution at room temperature with a maximum at 486–520 nm, quantum yield of 61–67%, and an excited-state lifetim…
Iron-Promoted Nucleophilic Additions to Diimine-Type Ligands: A Synthetic and Structural Study
2003
We report here three examples of the reactivity of protic nucleophiles with diimine-type ligands in the presence of Fe(II) salts. In the first case, the iron-promoted alcoholysis reaction of one nitrile group of the ligand 2,3-dicyano-5,6-bis(2-pyridyl)-pyrazine (L1) permitted the isolation of an stable E-imido-ester, [Fe(L1')(2)](CF(3)SO(3))(2) (1), which has been characterized by spectroscopic studies (IR, ES-MS, Mössbauer), elemental analysis, and crystallographically. Compound 1 consists of mononuclear octahedrally coordinated Fe(II) complexes where the Fe(II) ion is in its low-spin state. The iron-mediated nucleophilic attack of water to the asymmetric ligand 2,3-bis(2-pyridyl)pyrido[3…
Tautomerism of Diazepines Fused with Pyrimidine Rings.
2003
The tautomerism of 1,4-diazepines fused with pyrimidine rings was studied by means of nmr spec-troscopy, X-ray analysis and quantum chemical calculations. It was found that in the case of 6,8-diphenyl-pyrimido[4,5-b][1,4]diazepin-4-ols (7a - e) the enamine form is more stable than the diimine form. This result is rationalized with the electron-withdrawing effect of the 4-hydroxypyrimidine ring and with the formation of intermolecular hydrogen bonds. In contrast to 7a - e, the 6,8-diaryl-2,3,4,7-tetrahydro-1,3-dimethyl-1H-pyrimido[4,5-b][1,4]diazepine-2,4-diones (9a, c, f) exist in the diimine form.
Templated synthesis of a rotaxane with a [Ru(diimine)3]2+ core.
2003
A rotaxane containing a ruthenium bisphenanthroline complex, acting as an axis, and a macrocycle incorporating a 2,2'-bipyridine (bpy) unit, threaded by the axis, has been synthesized. The bisphenanthroline ligand is such that its ruthenium(II) complexes possess a clearly identified axis, making such compounds ideal components of rotaxanes constructed around an octahedral ruthenium(II) center, which serves as a template. The ring is threaded by the axial ruthenium(II) precursor complex, to afford the corresponding pseudorotaxane in moderate yield. The X-ray structure analysis of this compound reveals the threaded nature of the complex. The length of the threaded ring (35 atoms in the periph…
CCDC 1042276: Experimental Crystal Structure Determination
2015
Related Article: Shizhen Du, Qifeng Xing, Zygmunt Flisak, Erlin Yue, Yang Sun, Wen-Hua Sun|2015|Dalton Trans.|44|12282|doi:10.1039/C5DT00052A
CCDC 1831144: Experimental Crystal Structure Determination
2018
Related Article: Ruikai Wu, Yifan Wang, Randi Zhang, Cun-Yue Guo, Zygmunt Flisak, Yang Sun, Wen-Hua Sun|2018|Polymer|153|574|doi:10.1016/j.polymer.2018.08.056