Conformational study of N,N-dimethyl-1,3-diaza-5,6-benzocycloheptene

¹H and ¹³C variable temperature NMR results show that the seven-membered heterocycle $\text{2}$ exists solely in the Cea form, a situation very different from the analogous six-membered $\text{1}$ which exists predominantly in the Cee form.     

Photopolymerization of N-substituted phenyl maleimide initiated with N,N-dimethyl-4-toluidine

Several N-phenyl maleimides with different p-substituents have been synthesized from the maleic anhydride and relevant aromatic amine. In the presence of N,N-dimethyl-4-toluidine (DMT), the N-substituted phenyl maleimide (4-XPhMIs) could be polymerized under UV irradiation. It was observed that a new absorption appeared on the UV-Vis spectrum of the mixture solution of 4-XPhMI and DMT, which reveals the formation of charge-transfer complex in the ground state. It was found that the fluorescence of DMT was quenched by 4-XPhMI and the quenching constant of 4-XPhMI, obtained from the Stern–Volmer plot, increases with the electron-deficiency of ethylene double bond of 4-XPhMI. The dynamic quenching of the fluorescence of DMT by 4-XPhMI suggests the formation of exciplex in excited state between DMT and 4-XPhMI. The radicals formed in the systems have been detected by spin-trapping techniques and electron paramagnetic resonance (EPR) spectrometer. Based on all of these results, it has been proposed that the initiation process of the polymerization involves the formation of exciplex and the initial radicals were produced by proton-transfer in the exciplex from DMT to 4-XPhMI. © 1997 John Wiley & Sons, Inc.     

Copper(II) complexes of N,N-dimethyl-2-picolinamine N-oxide

Cu(II) complexes have been prepared with N,N-dimethyl-2-picolinamine N-oxide (DMA) employing the tetrafluoroborate, nitrate, chloride and bromide salts. Complexes having 1:2 and 1:1 metal ion to ligand ratios have been isolated. Characterization has been accomplished by IR, electronic and ESR spectral measurements of the solid state. Significant changes occurred when spectral measurements of acetonitrile solutions of the various solids were attempted indicating alteration of the Cu(II) bonding occurs. Thermal data on the solids are included.     

Hydrothiolysis of N,N-dimethyl-3-methylsulfanyl-3-phenylprop-2-en-1-iminium iodide

Russian Journal of Organic Chemistry -     

Synthesis,Crystal Structure and Photoluminescence Property of Ag(I) with N,N-dimethyl-4-(pyridine-4-yldiazenyl)aniline

A 2D plane coordination compound [Ag_2(Dpya)_2.(NO_3)_2]n was synthesized and characterized by FT-IR,elemental analysis and TG analysis.The red crystal was obtained via solvent diffusion method at room temperature and is slightly soluble in organic solvents.Its structure was determined by single-crystal X-ray diffraction analysis.It crystallizes in monoclinic,space group P1 with a = 10.7995(13),b = 7.4748(8),c = 18.364(2) ?,β = 98.916(4)o,V = 1464.5(3) ?~3,Z = 2,C_(26)H_(28)Ag_2N_(10)O_6,M_r = 792.32,Dc = 1.302 Mg/m~3,F(000) = 792,μ(Mo Ka) = 1.356 mm~(-1),R = 0.0575 and w R = 0.0826.The compound [Ag_2(Dpya)_2.(NO_3)_2]_n is a two-dimensional structure and there are two kinds of coordination configurations about the Ag atoms in the compound.The Ag(1) center is tetrahedrally coordinated with two O atoms of NO_3~-and two N atoms from the ligand Dpya.Meanwhile,the Ag(2) is five-coordinated by five O atoms from three NO_3~-anions.The Ag centers(Ag(1) and Ag(2)) connect to themselves as well as with each other by the bridging NO_3~-anions.And the coordination compound shows photoluminescence with an emission peak at 530 nm(λex = 450 nm) as the ligand Dpya.     

OPA method modified by use of N,N-dimethyl-2-mercaptoethylammonium chloride as thiol component

Summary In the analysis of biological matrices, the application of o-phthaldialdehyde in the presence of a thiol component (OPA-method) for the quantitative determination of free - and -amino groups in amino acids, peptides and proteins as well as their hydrolytic or proteolytic products, respectively, is well known. The most frequently used thiol compound is mercaptoethanol. The use of this substance has the disadvantage that the initially generated isoindole often undergoes intramolecular rearrangement which often leads to a decrease in extinction at the monitoring wavelength of 340 nm. The present paper describes a modified method in which mercaptoethanol was replaced by N,N-dimethyl-2-mercaptoethylammonium chloride. The use of the new thiol component in the OPA reaction results in long-term stability of the extinction values (plateauing > 1 h). The modified method is further characterized by high accuracy and precision.

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Modifizierte OPA-Methode mit N,N-Dimethyl-2-mercaptoethylammoniumchlorid als Thiolkomponente

     

Electrochemical behavior of 2'-halogenated derivatives of N,N-dimethyl-4-aminoazobenzene at mercury electrode.

The electrochemical behavior of 2'-halogeno-N,N-dimethyl-4-aminoazobenzene derivatives was investigated using various polarographic and voltammetric methods. The peak potentials of these derivatives were observed to shift towards negative values along with an increase in the pH. A reduction of the azo linkage took place via two electrons at pH > 4, but four electrons at pH < 4 in aqueous-ethanol mixtures. The standard rate constants were determined with (Laviron technique) or without (Nicholson technique) taking the adsorption phenomena into account. The diffusion coefficients were calculated from the cyclic voltammetric data using a method developed by Garrido. The amount of adsorbed substances and transfer coefficients for the electron transfer were also determined. A mechanism for the electrode reaction is proposed. These compounds can be quantitatively determined between 1 x 10(-5) M and 1 x 10(-7) with DPP and CV.