六方硼碳氮化合物的溶剂热合成与表征

采用溶剂热合成方法,以无水乙腈、叠氮化钠和四氟硼酸钠为原料,以苯为溶剂,在温度为400℃条件下,成功合成出了硼碳氮(BCN)三元化合物.利用X射线粉末衍射(XRD)、Fourier变换红外光谱(FTIR)、透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线能谱(EDS)和电子能量损失谱(EELS)对合成产物进行了表征.XRD和SAED分析表明,合成产物为六方相,晶格常数为a=0.2678nm,c=0.6639nm;TEM结果表明,合成产物中存在纳米棒和四方柱状块体BCN;EELS和EDS分析表明,产物由B,C,N三种元素组成,化学式为B0.23C0.60N0.17;FTIR分析表明样品中存在C—N,B—C和B—N键,表明B,C,N三元素之间达到了原子级化合.     

硼团簇、硼烷及金属硼化物的研究现状

硼原子因其半径小、缺电子、配位数大、价电子sp²杂化和三中心键等特点引起了科学家的高度关注。其团簇的电子结构、稳定性、芳香性和成键方式等性质的研究成为化学领域的一大热点。由于硼化物多样性的特点,其在光学、能源和储存工业气体方面具有潜在的应用价值。本文简述了近几年全硼团簇、硼烷及金属硼化物的研究现状。其中,分别从中性、阴离子和阳离子三种形式对全硼团簇和硼烷进行概括;金属掺杂硼化物主要包括金属掺杂的纯硼团簇和硼烷、过渡金属掺杂的三明治形式复合物以及金属中心硼分子轮。     

Synthesis and Investigation of Energetic Boron Compounds for Pyrotechnics

The energetic boron esters tris(1‐ethyl‐5‐aminotetrazolyl) borate, tris(2‐ethyl‐5‐aminotetrazolyl) borate, tris(1‐ethyltetrazolyl) borate, tris(2‐ethyltetrazolyl) borate, and tris(2‐(3‐nitro‐1, 2,4‐triazolyl)ethyl) borate were synthesized and analyzed by NMR and IR spectroscopy, elemental analysis, and mass spectrometry. Two tetracoordinate borates potassium tetrakis(3‐nitro‐1, 2,4‐triazolyl)borate and potassium bis(4, 4′,5, 5′‐tetranitro‐2, 2′‐bisimidazolyl)borate were synthesized and fully characterized as well. Moreover, the energetic and thermal properties of the energetic boron esters and tetracoordinate borates were determined. The ¹¹B NMR chemical shifts of potassium tetrakis(3‐nitro‐1, 2,4‐triazolyl)borate and potassium bis(4, 4′,5, 5′‐tetranitro‐2, 2′‐bisimidazolyl)borate were calculated and compared to the experimental values. Tris(1‐ethyl‐5‐aminotetrazolyl) borate was tested as colorant in pyrotechnic formulations with respect to the combustion behavior and color properties as well as the energetic and thermal properties.     

A New Target for Synthesis: Theoretical Prediction for the Reaction between Boron Nitride Nanotube and Dichlorocarbene

Understanding the chemistry of BNNT is a crucial step toward their ultimate practical use. A comparative study of Reactions A （ASWCNT （5,5） and CCl2） and B （ASWBNNT （5,5） and CCl2） have been performed by using ONIOM （B3LYP/6-31G＊： AM1） method in Gaussian03 program package. The results show that （1） the two reactions are both exothermic; （2） the mechanism of Reaction B is a two-step mechanism; （3） the difference in energy barriers suggests that the reaction of CCl2 with BNNT is easier than with CNT; （4） in reaction B, CCl2 prefers to attack the boron atom of BNNT first.     

有机硼化合物的质谱分析

对有机硼化合物进行质谱分析,考察不同种类仪器对样品分析的影响,确定使用电喷雾质谱仪效果最好。进一步考察了流动相、正负离子检测模式、离子化试剂及其浓度等因素的影响。实验发现:样品浓度为1×10-4mol/L,使用V(甲醇):V(H2O)=1:1的混合溶剂为流动相,正离子检测,0.1mol/LNa 为离子化试剂条件下可得到满意的谱图。     

PdO-Catalyzed Synthesis of Tricyclic Compounds Using Biginelli-Like Reaction

An efficient method has been successfully developed for the synthesis of oxygen-bridged pyrimidine tricyclic derivatives from salicylaldehyde, ethyl acetoacete, and urea catalyzed by PdO in very good yield. A series of different oxygen-bridged pyrimidine tricyclic derivatives has been synthesized, in which two compounds’ x-ray crystal structure were obtained.     

甲胺/二甲胺共取代合成氮化硼先驱体聚硼氮烷

将三氯环硼氮烷(TCB)与甲胺/二甲胺进行共胺解取代反应, 首先制得了不同胺基的取代单体, 经过进一步热聚合反应合成了聚硼氮烷先驱体. 通过对不同单体的聚合产物组成与结构分析, 探讨了不同取代基对热聚合反应及产物结构的影响. 研究表明, 当控制甲胺/二甲胺摩尔比为1∶2, 聚合温度180 ℃, 获得的聚硼氮烷数均分子量为7603, 分子量分散系数为1.80, 熔点为83 ℃, 组成为BC_0.76N_1.39H_2.5, 该聚合物具有近似线性分子结构, 表现出优良的可纺性, 可制得平均直径10～15 μm的先驱体纤维, 为制备氮化硼纤维奠定了基础.     

Boron Hydrogen Compounds: Hydrogen Storage and Battery Applications

About 25 years ago, Bogdanovic and Schwickardi (B. Bogdanovic, M. Schwickardi: J. Alloys Compd. 1–9, 253 (1997) discovered the catalyzed release of hydrogen from NaAlH₄. This discovery stimulated a vast research effort on light hydrides as hydrogen storage materials, in particular boron hydrogen compounds. Mg(BH₄)₂, with a hydrogen content of 14.9 wt %, has been extensively studied, and recent results shed new light on intermediate species formed during dehydrogenation. The chemistry of B₃H₈⁻, which is an important intermediate between BH₄⁻ and B₁₂H₁₂²⁻, is presented in detail. The discovery of high ionic conductivity in the high-temperature phases of LiBH₄ and Na₂B₁₂H₁₂ opened a new research direction. The high chemical and electrochemical stability of closo-hydroborates has stimulated new research for their applications in batteries. Very recently, an all-solid-state 4 V Na battery prototype using a Na₄(CB₁₁H₁₂)₂(B₁₂H₁₂) solid electrolyte has been demonstrated. In this review, we present the current knowledge of possible reaction pathways involved in the successive hydrogen release reactions from BH₄⁻ to B₁₂H₁₂²⁻, and a discussion of relevant necessary properties for high-ionic-conduction materials.     

A New Class of Boron Nanotube

The configurations, stability and electronic structures of a new class of boron sheet and related boron nanotubes are predicted within the framework of density functional theory. This boron sheet is sparser than those of recent proposals. Our theoretic results show that the stable boron sheet remains flat and is metallic. There are bands similar to the π‐bands in graphite near the Fermi level. Stable nanotubes with various diameters and chiral vectors can be rolled from the sheet. Within our study, only the thin (8, 0) nanotube with a band gap of 0.44 eV is semiconducting, while all the other thicker boron nanotubes are metallic, independent of their chirality. It indicates the possibility, in the design of nanodevices, to control the electronic transport properties of the boron nanotube through the diameter.     

利用水热合成方法制备正交氮化硼微晶

利用水热方法制备了正交氮化硼微晶, 于400 ℃时制备的氮化硼结晶质量较高, 主要物相为正交氮化硼(oBN). 在反应原料中加入水合肼和氯化铵都有利于样品结晶质量的改善和产率的提高. 在合成氮化硼反应过程中, 适当减慢反应体系的升温速率有利于提高oBN的结晶质量和产率, 但是当升温速率过慢时, oBN的稳定性有所降低, 立方氮化硼(cBN)的稳定性则在一定程度上得到提高. 此外, 反应过程中的原料配比对样品的物相及其结晶质量也有很大影响.     

氮化硼纤维先驱体的制备与表征

以三氯环硼氮烷为原料, 将其与正丙胺/异丙胺进行共取代反应, 制得了不同结构的取代单体, 再经热聚合反应获得了相应的聚硼氮烷先驱体. 通过分析不同正丙胺/异丙胺配比制得的聚合产物的组成与结构, 探讨了不同单体的胺基取代基对先驱体的聚合反应性及对产物结构的影响. 结果表明, 当正丙胺/异丙胺摩尔比为2∶1, 聚合温度为150 ℃, 反应时间为10 h时, 合成产物具有近似线性分子结构, 熔点为90 ℃, 具有良好的成丝性, 可获得平均直径10~20 μm, 组成为BC_1.27N_1.52H_x的先驱体纤维, 先驱体纤维再经不熔化处理及1200 ℃氨气高温煅烧等工艺可获得近化学计量比的氮化硼纤维.     

硫辅助合成高孔隙率大孔氮化硼材料

采用硫粉辅助的方法合成了具有一定有序孔洞结构的三维大孔氮化硼材料,具有高比表面积(230 m2.g-1)和高孔隙率(85.6%),并呈现开孔结构。在未加入硫粉的情况下则只形成完全无序的三维大孔氮化硼,并且比表面积和孔隙率分别降至122m2.g-1和73.7%。热重测试表明两种产品均具有良好的抗氧化性能。本文还对这种大孔材料的形成过程和硫粉的作用进行了初步的探讨。     

Binary Compounds of Boron and Beryllium: A Rich Structural Arena with Space for Predictions

We explore ground‐state structures and stoichiometries of the Be? B system in the static limit, with Be atom concentrations of 20 % or greater, and from P=1 atm up to 320 GPa. At P=1 atm, predictions are offered for several known compounds, the structures of which have not yet been determined experimentally. Specifically, at 1 atm, we predict a structure of R$\bar 3$ m symmetry for the compound Be₂B₃, seen experimentally at high temperatures, which contains interesting BeBBBBe rods; and for the compound BeB₄ we calculate metastability with respect to the elements with a structure similar to MgB₄, which is quickly replaced as the pressure is elevated by a Cmcm structure that features 6‐ and 4‐membered rings in B cages, with Be interstitials. For another high‐temperature compound, Be₂B, we confirm the CaF₂ structure, but find a competitive and actually slightly more stable ground‐state structure of C2/m symmetry that features B₂ pairs. In the case of BeB₂, a material for which the stoichiometry has been the subject of debate, we have a clear prediction of a stable F$\bar 4$ 3m structure at P=1 atm. It has a diamondoid structure that is based on cubic (lower P) or hexagonal (higher P) diamond networks of B, but with Be in the interstices. This Zintl structure is a semiconductor at low and intermediate pressures. At higher pressures, BeB₂ dominates the phase diagram. In general, the Zintl–Klemm concept of effective electron transfer from the more electropositive ion and bond formation among the resulting anions has proven useful in analyzing the structural preferences of many compositions in the Be? B system at P=1 atm and at elevated pressures. An unusual feature of this binary system is that the 1:1 BeB stoichiometry never appears to reach stability in the static limit, although it comes close, as does Be₁₇B₁₂. Also stable at high pressures are stoichiometries BeB₃, BeB₄, and Be₅B₂.     

Synthesis of Acylboron Compounds

Acylboron compounds are emerging as versatile functional groups with applications in multiple research fields. Their synthesis, however, is still challenging and requires innovative methods. This Minireview provides an overview on the obstacles of acylboron synthesis and highlights notable advances within the last three years on new strategies to overcome the challenges posed by the formation of acyl–boron bonds.     

硼铝磷酸盐分子筛(BAPO-11)的合成与表征

采用静态水热法合成了具有AEL结构的硼铝磷酸盐分子筛(BAPO-11),利用XRD、BET、FTIR及SEM等方法对BAPO-11进行了表征.研究结果表明,当活性胶液中的硼和磷的相对含量为0相似文献   

新型间氯苯基卟啉-5-氟尿嘧啶化合物的合成与表征

用5-[3-(3-溴丙氧基)苯基]-10,15,20-三(3-氯苯基)卟啉或5-[3-(4-溴丁氧基)苯基]-10,15,20-三(3-氯苯基)卟啉与5-氟尿嘧啶反应,合成了1,3-二[5-(3-丙氧基苯基)-10,15,20-三(3-氯苯基)卟啉]-5-氟尿嘧啶(A1)、1-[5-(3-丙氧基苯基)-10,15,20-三(3-氯苯基)卟啉]-5-氟尿嘧啶(B1)、1,3-二[5-(3-丁氧基苯基)-10,15,20-三(3-氯苯基)卟啉]-5-氟尿嘧啶(A2)、1-[5-(3-丁氧基苯基)-10,15,20-三(3-氯苯基)卟啉]-5-氟尿嘧啶(B2),产率分别为20.4%、12.3%、21.4%、11.4%。通过红外光谱、紫外可见光谱、核磁共振谱和基质辅助激光解吸-电离飞行时间质谱测试技术表征了其结构。对目标化合物的合成分离纯化条件进行了研究。结果表明,选择DMF为溶剂,反应温度在120℃,反应时间10h,产率较高;采用硅胶G(粒径40μm)柱层析,按试验产品量,柱子直径为3cm,柱高10cm,用V(氯仿)∶V(丙酮)=15∶1为洗脱剂,分离效果较好。     

三氟化硼和水反应的密度泛函理论研究

应用密度泛函理论对三氟化硼和水的反应进行了研究. 在 B3PW91/6-31＋＋G(d,p)水平上优化了各驻点(反应物, 中间体, 过渡态和产物)的几何构型, 并计算了它们的振动频率和零点振动能, 并对能量进行了校正. 计算结果表明, 三氟化硼和水的反应比较复杂, 产物除氟化氢外, 还有硼酸, 氟硼酸, 硼氟氧酸等.