Fabrication and optical properties of MgxZn1-xO thin films

MgxZn1xO (x ≤ 0.3) thin films have been prepared on silicon substrates by radio frequency magnetron sputtering at room temperature. The thin films have hexagonal wurtzite single-phase structure and a preferred orientation with the c-axis perpendicular to the substrates. The Mg content in the films is slightly larger than that in the targets. The refractive indices of MgxZn1xO films measured at room temperature by spectroscopic ellipsometry (SE) on the wavelength 632.8 nm are systematically decreased with the increasing of Mg content. Optical band gaps of Mg x Zn 1 x O films are determined by the transmittance spectra. With increasing Mg content, the absorption edges of MgxZn1xO films shift to higher energies and band gaps linearly increase from 3.24 eV at x=0 to 3.90 eV at x=0.30.     

氮杂环卡宾催化α,β-不饱和酰氯与亚硝基化合物的[4+2]环化反应

报道氮杂环卡宾催化的α,β-不饱和酰氯与亚硝基化合物的形式[4+2]环化反应合成氮杂-δ-内酯([1,2]嗪-6-酮)化合物.反应机理推测可能是卡宾进攻现场生成的烯基烯酮,得到烯基烯醇负离子,然后与取代的亚硝基苯发生[4+2]环合反应,从而得到的氮杂-δ-内酯产物.