一种新BCN化合物先驱体的合成及其表征

Synthesis and Characterization of a Novel Precursor for BCN Compound

以三聚氰胺和硼酸为原料在水溶液中反应合成了一种新的BCN化合物先驱体,通过元素分析、XRD、FT-IR、电喷雾质谱及单晶X射线衍射对其进行了表征.结构分析表明该化合物属单斜晶系,化学式为C3H6N6(H3BO3)2,是由C3H6N6分子和H3BO3分子通过氢键加合组装成的具有三维超分子结构的化合物.将该先驱体在1900℃氮气气氛下热解,对产物进行XRD和XPS表征,结果表明得到了含碳量较低的具有乱层石墨结构的新型B3CN3化合物.

A novel precursor for BCN compound, C3H6N6（H3BO3）2, was synthesized with C3H6N6 melamine and H3BO3 as raw materials in aqueous solution. The precursor was characterized by elementary analysis, XRD, Fr-IR, electrospray mass spectrometry and single crystal X-ray diffraction. It revealed that the precursor contained the characteristic groups of C3H6N6 and H3BO3 such as triazine ring, NH2, and B-OH. The precursor crystallized in monoclinic space group P21 / c, with the cell parameters a=0.35970（7） nm, b=2.0105（4） nm, c=1.4112（3） nm, β=92.07（3）°, Z=4. One crystallographically distinct C3H6N6 molecule and two H3BO3 molecules constituted the asymmetric unit of the precursor. A 3D supramolecular network was constructed by different hydrogen-bonding interactions between C3H6N6 and H3BO3 molecules. The precursor was further pyrolyzed at 1900 ℃ under flowing N2 atmosphere. XRD and XPS analysis were applied for the characterization of the pyrolysis product. The results indicated that a new BCN ternary compound with turbostratic graphite structure was obtained. B-N, B-C, and C-N chemical bonds were established and there was no phase separation between graphite and h-BN, which suggests an atomic-level hybrid of B, C, and N elements in the compound. The BCN compound has lower carbon content and its empirical formula can be expressed as B3CN3.