Synthesis and Crystal Structure of a 2-D Hydrogen-bonded Supramolecular Network {[Cu_4(OH)_4(2,2'-bpy)_4(bqdc)]·2ClO_4}_n

The title compound {[Cu4(OH)4(2,2'-bpy)4(bqdc)]·2ClO4}n 1 (bqdc = 2,2'-biquino- line-4,4'-dicarboxylic acid) has been synthesized by hydrothermal method. Its crystal structure is of triclinic, space group P1 with a = 7.6561(5), b = 12.4652(8), c = 15.7501(10) , α = 80.0480(10), β = 87.7900(10), γ = 74.0800(1)o, V = 1423.65(16) 3, Z = 2, C30H23ClN5O8Cu2, Mr = 744.06, Dc = 1.736 g/cm3, μ = 1.651 mm─1, F(000) = 754, the final R = 0.0421 and wR = 0.1163 for 4973 observed reflections with I > 2σ(I). In 1, tetra-copper chair-like clusters of [Cu4(OH)4(2,2'-bpy)4]4+ are connected by bqdc ligands to form one-dimensional chains, which are further connected by hydrogen bonds to generate a two-dimensional supramolecular network .     

Heat Storage Performance of Disodium Hydrogen Phosphate Dodecahydrate： Prevention of Phase Separation by Thickening and Gelling Methods

Disodium hydrogen phosphate dodecahydrate （Na2HPO4·12H2O） is an attractive candidate for phase change materials. The main problem for its practical use comes from incongruent melting character during thermal cycling. Experimentally, heat of fusion of the pure salt decreased from 200 to 25 jog 1 in a four-run freeze-thaw cycling. Additives such as thickening agent or in-situ synthesized polyacrylate sodium in the molten salt can prevent its phase separation to some extent. In the test, sodium alginate 3.0%-5.0% （w/w） thickened mixture containing Na2HPOn·12H2O and some water showed constant heat storage capacities. Polyacrylate sodium gelled salt was synthesized through polymerizing sodium acrylate in the melt of Na2HPOn·12H2O and some extra water at 50 ℃. Optimum conditions composed of sodium acrylate 3.0%-5.0% （w/w）, cross-linking agent N,N-methylenebis-acrylamide 0.10%-0.20% （w/w）, K2S208 and Na2SO3 （mass ratio 1 ; 1） 0.06%-0.12% （w/w）. As opposed to normal large crystals of pure Na2HPOn·12H2O in solid state, the gelled salt existed in a large number of tiny particles dispersed in the gel network at room temperature, commonly less than 2 mm. But only those sample particles with sizes less than 0.2 mm may have relatively stable thermal storage property. A problem encountered was the poor reproducibility of the synthesis method： heat storage capacity of the product was often very different even though the synthesis was carried out in the same conditions. An alternative gelling method by sodium alginate grafted sodium acrylate was tried and it showed a fairly good effect. Heat capacities and heat of fusion of Na2HPO4·12H2O were measured by an adiabatic calorimeter.     

Synthesis and Crystal Structure of a 2-D Hydrogen-bonded Supramolecular Network {[Cu4(OH)4(2,2''-bpy)4(bqdc)]·2ClO4}n

The title compound {[Cu4(OH)4(2,2'-bpy)4(bqdc)]·2ClO4}n 1 (bqdc = 2,2'-biquinoline-4,4'-dicarboxylic acid) has been synthesized by hydrothermal method. Its crystal structure is of triclinic, space group P-1 with a = 7.6561(5), b = 12.4652(8), c = 15.7501(10) (A), α= 80.0480(10), β= 87.7900(10), γ = 74.0800(1)°, V = 1423.65(16) (A)3, Z = 2, C30H23ClN5O8Cu2, Mr = 744.06, Dc = 1.736 g/cm3, μ = 1.651 mm-1, F(000) = 754, the final R = 0.0421 and wR = 0.1163 for 4973 observed reflections with Ⅰ＞ 2σ(Ⅰ). In 1, tetra-copper chair-like clusters of [Cu4(OH)4(2,2'-bpy)4]4 are connected by bqdc ligands to form one-dimensional chains, which are further connected by hydrogen bonds to generate a two-dimensional supramolecular network .     

不同耐热合金上油页岩干馏瓦斯丙烯组分的积炭特性

采用自制的连续流动反应装置,分别以2520及316L不锈钢管为反应器,对不同气体流量(20ml.min_-1,30ml.min_-1,40ml.min_-1)、不同壁温(700℃,750℃,800℃)、恒定反应时间(20min)等条件下干馏瓦斯中丙烯组分在不同反应器内积炭特性进行了实验研究,得出两种管壁上初始积炭温度范围为630℃~650℃及670℃~690℃;结合扫描电子显微镜对积炭微观形态进行观察,结果表明管内积炭都以丝状炭和无定形炭为主;用程序升温氧化方法对不同工况下两种反应管内积炭量进行分析,得出316L耐热合金具有抗金属粉化特性;运用热重及差示扫描量热法对管内剥离炭样活性进行表征,结果验证316L耐热合金内积炭活性高于2520耐热合金内积炭。     

超高效液相色谱-串联质谱法同时测定蜂蜜中硝基咪唑类、磺胺类、喹诺酮类兽药残留

建立蜂蜜样品中硝基咪唑类、磺胺类、喹诺酮类共36种兽药残留的固相萃取-超高效液相色谱-串联质谱检测方法。蜂蜜样品用H3PO4溶液(体积分数0.1%)溶解后,过滤,用Oasis HLB和PSA固相萃取柱净化,外标法定量。测定时用Eclipse Plus C18色谱柱(100 mm×2.1 mm,1.8μm)分离,乙腈-甲醇-甲酸溶液梯度洗脱,质谱测定采用多反应监测(MRM)模式。36种兽药的检出限在0.4～4.0 ng/mL,回收率在63.2%～125.5%,相对标准偏差均低于22%。     

浓缩果汁中20种氨基酸的超高效液相色谱-串联质谱法同时测定

建立了同时测定浓缩果汁中20种氨基酸含量的超高效液相色谱-串联质谱法(UPLC-MS/MS)。样品经异硫氰酸苯酯(PITC)衍生,0.1%甲酸(含1 mmol.L-1甲酸铵)-乙腈溶液定容后,采用ACQUITY UP-LC(BEHC18(1.7μm×2.1 mm×50 mm)色谱柱分离,以0.1%甲酸(含1 mmol.L-1甲酸铵)-乙腈溶液为流动相,在0.3 mL.min-1流速下梯度洗脱,MS/MS检测、外标法定量。果汁中除天门冬氨酸的检出限(LOD)为500.0 ng.g-1外,其它均为100.0 ng.g-1。线性范围为10.0~1 000.0μg.L-1(r≥0.990 0),平均加标回收率为79%~120%,相对标准偏差(n=6)小于8.0%。该方法具有杂质干扰小、分析速度快、灵敏度高等特点,适用于果汁中氨基酸的定性定量分析。     

钴(Ⅱ)-氨基酸配合物催化性能与氧合性能的关系

研究了13种钴(Ⅱ)-氨基酸配合物的可逆氧合性能和催化性能之间的关系, 通过配合物活化分子氧(O₂)氧化环己烯考察其催化性能. 结果表明, 13种钴(Ⅱ)-氨基酸配合物均具有不同程度的可逆氧合性能和催化活性. 配合物完成一个可逆吸氧周期的用时越短, 其可逆氧合性能越好, 催化性能越差; 相反, 吸氧周期长及可逆氧合性能差的配合物其催化性能却更好. 另外, 在对配合物不同配比的研究中发现, Co(Ⅱ)与氨基酸的摩尔比为1:3(或1:2)饱和配位时, 可逆吸氧性能较好, 但其催化性能较差, 环己烯转化率较低; 在1:1型配位不饱和时, 吸氧的可逆性较差, 但催化性能优良, 环己烯的转化率可达82.5%. 结合结构分析和理论计算的结果可知, 不同钴(Ⅱ)-氨基酸配合物的氧合可逆性和催化性能的差异, 主要归因于氨基酸配体的残基与Co(Ⅱ)的结合能力的不同. 氨基酸配体的残基与Co(Ⅱ)的结合能力越好, 越有利于配合物由高自旋态向低自旋态转化, 并与O₂可逆结合, 不利于烯烃基的取代, 配合物表现出较差的催化性能, 反之亦然.     

一种在ATRP反应体系中常用引发组分--1-溴乙基苯的荧光光谱研究

采用荧光光谱和吸收光谱方法对ATRP聚合体系的常用引发组分——— 1 溴乙基苯与几种常用配体间的相互作用问题进行了研究 .发现当以联吡啶为络合物配体时 ,无论荧光和吸收光谱中均出现反常的新峰 ,这和 1 溴乙基苯与吡啶间发生了成盐反应有关 .在以长链脂肪胺为络合物配体时 ,特别当金属离子与配体的摩尔比为 1 4时 ,荧光光谱中可清晰的观察到激基复合物发光 .所观察到的这些现象 ,特别是 1 溴乙基苯与联吡啶间的成盐反应 ,对ATRP过程会产生不良影响 .而脂肪胺体系生成的激基复合物由于发生于激发态 ,因此它就不像联吡啶的成盐反应哪样 ,会严重影响反应进行 ,导致ATRP效率的降低 .     

利用HPLC-MS对精噁唑禾草灵微生物降解途径的研究

产碱菌属H(Alcaligenes sp.H)以及其紫外诱变菌Huv均可降解精噁唑禾草灵，液相色谱显示二者具有某一相同的精噁唑禾草灵微生物降解产物；利用高效液相色谱一质谱联用技术(HPLC—MS)，对上述精噁唑禾草灵微生物降解产物进行鉴定。结果表明：精噁唑禾草灵水解是降解菌Alcaligenes sp．H与Huv降解精噁唑禾草灵的公共降解途径之一，其产物为(R)-2-[4-(6-氯-1，3．苯并噁唑-2-基氧)苯氧基]丙酸和乙醇。     

改性球形天然石墨锂离子电池负极材料的研究

将天然鳞片石墨制成球形石墨,在其表面包覆一层纳米非石墨化碳材料制成具有核壳结构的改性球形石墨。实验结果表明:此法显著提高了天然石墨的振实密度、可逆容量(达365mAh·g-1 ),首次库仑效率( >93% )和循环稳定性(循环500次后,容量保持率>80% )。分析并讨论了负极材料的结构及其与电化学性能的关系。