稳定同位素标记D_4-罗丹明B的合成及表征

以全氘代邻二甲苯为同位素标记前体,经氧化得到的D_4-邻苯二甲酸与3-羟基-N,N-二乙基苯胺反应生成稳定同位素标记的D_4-罗丹明B,总收率36.9%。目标产物的结构经质谱(MS)、核磁(NMR)等技术手段表征确认,通过高效液相色谱确定化学纯度高于98.0%,同位素氘丰度大于98.0%。将其作为同位素内标试剂用于果汁中罗丹明B的残留检测,在0.05~50 mg/L范围内呈良好的线性关系,其检出限为5μg/kg,回收率为96.4%~103.4%,相对标准偏差(RSD)为1.0%~1.2%,具有很高的灵敏度和准确性。为食品安全领域违禁色素的检测提供了一种可靠实用的方法。     

双标记~(13)C,~(15)N_3-呋喃妥因的制备

以双标记13 C,15 N3-氨基脲为原料,先与苯甲醛缩合,继而与氯乙酸乙酯取代、环化,再经盐酸水解反应后与5-硝基糠醛二乙酯反应,最终制得双标记13 C,15 N3-呋喃妥因.产物经红外光谱、高效液相色谱及质谱表征.结果表明,所选用的合成路线反应条件温和,产物总收率高于60%,且同位素丰度不下降;目标产物的化学纯度>99.0%,13 C同位素丰度>98%,15 N同位素丰度>99%.     

双核Pt(Ⅳ)配合物与Guanosine-5''''-Monophosphate和Glutathione反应的核磁共振光谱研究

合成了一个新型的双核Pt(Ⅳ)配合物{[cis-Pt(NH3)2Cl(OH)2]2(4,4'-methylenedianiline)}(NO3)2(化合物1)及相应的 15N标记化合物{[cis-Pt(15NH3)2Cl(OH)2]2(4,4'-methylenedianiline)}(NO3)2(化合物15N-1).利用1H NMR和ESMS进行了结构表征,化合物15N-1的2D[1H,15N]HSQC NMR发现,该化合物在水溶液中存在同分异构体.2D[1H,15N]HSQC NMR技术跟踪了化合物15N-1与Guanosine-5'-Monophosphate(5'-GMP)和Glutathione(GSH)的反应.结果显示,5'-GMP能在0.5 h内将化合物1还原,而GSH在6 h以后才能够部分的将化合物1还原.化合物1所表现出来的反应性能将有利于提高其治疗效果和降低毒副作用.     

土壤铵态氮中氮稳定同位素比值测定前处理方法优化研究

土壤氮素在土壤养分供给和植物生长发育中起着重要作用。利用氮稳定同位素自然丰度或富集标记技术,开展土壤氮循环转化、化肥利用效率和生物有效性等方面的研究,涉及NH4+-N稳定同位素比值的精准测定。本研究在前人基础上,开发了一种快速高通量的铵态氮蒸馏分离方法,并使用次氯酸盐替代了次溴酸盐优化了铵态氮化学转化条件,将转化效率由原方法的25%左右,提高至60%以上。利用新建立的前处理方法结合气体预浓缩装置与稳定同位素质谱仪（PreCon-IRMS）联用系统,分析了不同浓度条件下自然丰度、15N富集和标记的NH4+-N标准溶液中的氮稳定同位素比值。结果表明,新的反应体系下,当铵态氮浓度为0.5 μmol /mL以上时,所有NH4+-N标准样品均能获得较理想的分析精度,其中自然丰度和15N富集参比溶液的NH4+-N的δ15N的精度可控制在0.5‰以内,而15N标记的标准溶液的15N atom%测试精度为0.001~0.006 atom%（CV在0.1~0.3%之间）。所有NH4+-N标准样品的15N测定值与参考值一致,无分馏现象发生。将该方法应用于两种不同土地类型的旱地和稻田土壤浸提液中NH4+-N稳定同位素丰度的测定,也可获得较好的重现性（CV<0.5%）,与原方法测定结果基本一致,且精度更优。优化后的前处理方法操作简单,耗时短,重复性好,适用于土壤溶液铵态氮15N丰度测定的快速、批量前处理。     

光引发剂(4-甲苯基)(4-异T基苯基)碘鎓六氟磷酸盐的合成研究

以对甲苯胺为原料,经重氮化、KI分解得到对-碘甲苯.在NH4Cl存在下,对-碘甲苯在过硫酸铵的氧化下与异丁苯反应,得到(4-甲苯基)(4-异丁基苯基)碘鎓氯.在丙酮溶剂中,(4-甲苯基)(4-异丁基苯基)碘鎓氯与六氟磷酸钾进行离子交换,得到目的产物(4-甲苯基)(4-异丁基苯基)碘鎓六氟磷酸盐.总收率为46.7%.通过...     

光引发剂(4-甲苯基)(4-异丁基苯基)碘鎓六氟磷酸盐的合成研究

以对甲苯胺为原料,经重氮化、KI分解得到对-碘甲苯.在NH4Cl存在下,对-碘甲苯在过硫酸铵的氧化下与异丁苯反应,得到(4-甲苯基)(4-异丁基苯基)碘鎓氯.在丙酮溶剂中,(4-甲苯基)(4-异丁基苯基)碘鎓氯与六氟磷酸钾进行离子交换,得到目的产物(4-甲苯基)(4-异丁基苯基)碘鎓六氟磷酸盐.总收率为46.7%.通过紫外光谱、红外光谱和核磁共振测定,对产物进行了结构确证.     

同位素质谱仪测定小麦植株各器官δ15N值的考察

建立了15N标记的小麦植株各器官中δ~(15)N值的元素分析仪-同位素比质谱仪联用技术(EA-IRMS)的测定方法.对仪器的稳定性和线性进行了条件优化,标准气N_2的同位素比值的标准偏差为0.03‰,在同位素信号值1e~(-9)~1e~(-8)A范围内,总体线性为0.009‰/n A.称取不同量的小麦粉标准物质(OAS/Isotope)测定δ~(15)N值,进样量为4 mg时标准偏差最小,为最佳称样量.对硫酸铵标准物质(IAEA-N2-6)、小麦粉标准物质和~(15)N标记小麦植株样品各器官进行测定,δ~(15)N值的标准偏差均小于5%,测定精度和准确度较好.方法为研究氮素在小麦体内运转及利用效率提供了有效的技术手段.     

基于电喷雾电离质谱(ESI-MS)的苯胺稳定同位素标记对还原性寡糖(链)的定性定量分析方法

建立了一种基于电喷雾电离质谱的苯胺稳定同位素标记对还原性寡糖链进行定性及相对定量分析的研究方法. 用苯胺标记乳糖标准品, 优化了影响标记效率的各种因素, 在弱酸性环境下, 选择糖链/苯胺/硼氢氰化钠的摩尔比为1∶1.2∶10, 于70 ℃反应15 min即可标记完全; 同时考察了4对d0/d5苯胺标记的麦芽糊精寡糖在电喷雾电离质谱中的线性、动态范围以及重现性. 结果表明, 在15倍动态范围内, 相对定量方法呈良好的线性关系(R=0.9986)和重现性(CV=10.20%). 为进一步验证定量方法的可靠性, 将其应用于人奶中游离寡糖(HMOs)和牛奶中游离寡糖(BMOs)的分析. 研究结果表明, 人奶中的乳糖含量高于牛奶, 人奶游离寡糖比牛奶游离寡糖种类复杂, 且岩藻糖基化程度高. 该方法成本低廉, 标记效率高且后处理方法简单方便, 适于微量样品通量化分析, 对差异糖组的研究有重要意义.     

芳基偶氮染料的高效合成

以4-硝基苯胺为原料,经重氮化反应后与2,5-二甲氧基苯胺偶联得芳基偶氮中间体2,5-二甲氧基-4-[(4-硝基苯基)二氮烯基]苯胺(3),3与亚硝酸异戊酯(4)重氮化后与N,N-二羟乙基苯胺(5)偶联合成了芳基二偶氮染料(6),其结构经1H NMR和13C NMR表征。考察了催化剂三氯乙酸和4用量及反应温度对6收率的影响。较优的反应条件为:以乙醇为溶剂,三氯乙酸为催化剂,三氯乙酸30 mmol,3 30 mmol,n(三氯乙酸)∶n(4)=1.0∶1.5,于0℃反应6 h,收率72%。     

固体酸催化二氟二苯甲酮和苯胺缩合合成N-(双(4-氟苯基)亚甲基)苯胺

以固体酸为催化剂,4,4’-二氟二苯甲酮与苯胺脱水缩合,合成了N-(双(4-氟苯基)亚甲基)苯胺.比较了不同固体酸催化剂H型ZSM-5、Na型ZSM-5、介孔分子筛MCM-41(Al)及强酸型离子交换树脂Amberlyst 15的催化效果.使用比表面、NH3-TPD对催化剂进行了表征,并与催化效果关联.考察了催化剂用量、原料摩尔比、浓度及溶剂等反应条件对产物收率的影响.产物通过熔点、核磁共振谱进行了表征.结果表明,HZSM-5固体酸催化剂具有优异的催化作用.在优化条件下,以对二甲苯为反应溶剂和脱水剂,4,4’-二氟二苯甲酮0.1 mol,苯胺0.2 mol,催化剂用量2.0 g,反应24 h,产物收率达91%.此外,催化剂易于分离,能够重复使用多次.     

Oxidation of ammonia in osmium polypyridyl complexes

The oxidations of cis- and trans-[OsIII(tpy)(Cl)2(NH3)](PF6), cis-[OsII(bpy)2(Cl)(NH3)](PF6), and [OsII(typ)(bpy)(NH3)](PF6)2 have been studied by cyclic voltammetry and by controlled-potential electrolysis. In acetonitrile or in acidic, aqueous solution, oxidation is metal-based and reversible, but as the pH is increased, oxidation and proton loss from coordinated ammonia occurs. cis- and trans-[OsIII(tpy)(Cl)2(NH3)](PF6) are oxidized by four electrons to give the corresponding OsVI nitrido complexes, [OSVI(typ)(Cl)2(N)]+. Oxidation of [Os(typ)(bpy)(NH3)](PF6)2 occurs by six electrons to give [Os(tpy)(bpy)(NO)](PF6)3. Oxidation of cis-[OsII(bpy)2(Cl)(NH3)](PF6) at pH 9.0 gives cis-[OsII(bpy)2(Cl)(NO)](PF6)2 and the mixed-valence form of the mu-N2 dimer [cis-[Os(bpy)2(Cl)2[mu-N2)](PF6)3. With NH4+ added to the electrolyte, cis-[OsII(bpy)2(Cl)(N2)](PF6) is a coproduct. The results of pH-dependent cyclic voltammetry measurements suggest OsIV as a common intermediate in the oxidation of coordinated ammonia. For cis- and trans-[OsIII(tpy)(Cl)2(NH3)]+, OsIV is a discernible intermediate. It undergoes further pH-dependent oxidation to [OsVI(tpy)(Cl)2(N)]+. For [OsII(tpy)(bpy)(NH3)]2+, oxidation to OsIV is followed by hydration at the nitrogen atom and further oxidation to nitrosyl. For cis-[OsII(bpy)2(Cl)-(NH3)]+, oxidation to OsIV is followed by N-N coupling and further oxidation to [cis-[Os(bpy)2(Cl)2(mu-N2)]3+. At pH 9, N-N coupling is competitive with capture of OsIV by OH- and further oxidation, yielding cis-[OsII(bpy)2(Cl)(NO)]2+.     

Enhanced anion binding of N-(anilino)thioureas. Contribution of the N-anilino-NH proton acidity

We report here that N-anilino-N'-phenythioureas in general function as a new family of thiourea-based efficient anion receptors superior to classical N-alkyl(aryl)thioureas, when the N-anilino-NH proton is acidic enough; that is, the N-phenyl substituent is not less electron-withdrawing than m-Cl. Changes due to anion binding in the absorption spectra of these N-anilinothioureas are much more substantial than those of N-alkyl(aryl)thioureas, and anion binding constants in MeCN, at 10(6)-10(7) mol(-1) L order of magnitude for AcO(-) for example, are much higher despite a similar acidity of the thioureido-NH protons. Crystal structure and (1)H NMR data show that the N-aniline chromophore is electronically decoupled from the thiourea anion binding site by the N-N bond, and an intramolecular hydrogen bond exists in MeCN but not in DMSO between the N-anilino-NH nitrogen atom and the other thioureido-NH proton. Conformation changes in the N-anilinothioureas upon anion binding were assumed to occur and lead to a much higher increment in the electron-donating ability in the N-aniline chromophore that the charge transfer (CT) is enhanced or switched on, compared to not switching on a CT in the case of N-phenylthioureas. The anion binding constant shows a stronger dependence on the N-phenyl substituent than on the N'-phenyl substituent, opposite to that observed with N-benzamidothioureas, and the CT band position of the anion binding complex depends much more on the N-phenyl substituent than that of the anion binding complexes of N-benzamidothioureas. The implications of these findings for new anion-receptors design and thiourea-based organocatalysts development are discussed.     

Preparation and reactivity of mixed-ligand iron(II) hydride complexes with phosphites and polypyridyls

Hydride complexes [FeH(N-N)P3]BPh4 (1, 2) [N-N = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen); P = P(OEt)4, PPh(OEt)2, and PPh2OEt] were prepared by allowing FeCl2(N-N) to react with phosphite in the presence of NaBH4. The hydrides [FeH(bpy)2P]BPh4 (3) [P = P(OEt)3 and PPh(OEt)2] were prepared by reacting the tris(2,2'-bipyridine) [Fe(bpy)3]Cl2.5H2O complex with the appropriate phosphite in the presence of NaBH4. The protonation reaction of 1 and 2 with acid was studied and led to thermally unstable (above -20 degrees C) dihydrogen [Fe(eta2-H2)(N-N)P3]2+ (4, 5) derivatives. The presence of the H2 ligand is indicated by short T(1 min) values (3.1-3.6 ms) and by J(HD) measurements (31.2-32.5 Hz) of the partially deuterated derivatives. Carbonyl [Fe(CO)(bpy)[P(OEt)3]3](BPh4)2 (6) and nitrile [Fe(CH3CN)(N-N)P3](BPh4)2 (7, 8) [N-N = bpy, phen; P = P(OEt)3 and PPh(OEt)2] complexes were prepared by substituting the H2 ligand in the eta2-H2 4, 5 derivatives. Aryldiazene complexes [Fe(ArN=NH)(N-N)P3](BPh4)2 (9, 10, 11) (Ar = C6H5, 4-CH3C6H4) were also obtained by allowing hydride [FeH(N-N)P3]BPh4 derivatives to react with aryldiazonium cations in CH2Cl2 at low temperature.     

On the Cl···N halogen bond: a rotational study of CF3Cl···NH3

The rotational spectra of six isotopologues (CF(3)(35)Cl···(14)NH(3), CF(3)(37)Cl···(14)NH(3), CF(3)(35)Cl···(15)NH(3), CF(3)(37)Cl···(15)NH(3), CF(3)(35)Cl···(14)ND(3) and CF(3)(37)Cl···(14)ND(3)) of the CF(3)Cl···NH(3) adduct have been investigated and analyzed by pulsed jet Fourier transform microwave spectroscopy. Rotational, centrifugal distortion and quadrupole ((35)Cl, (37)Cl, (14)N) coupling constants have been precisely obtained. The two subunits of the complex are held together via a Cl···N halogen bond interaction. Information on the internal dynamics and on the dissociation energy of the complex is provided.     

Enantioselective diene Cyclization/Hydrosilylation catalyzed by optically active palladium bisoxazoline and pyridine-oxazoline complexes

A 1:1 mixture of (N-N)Pd(Me)Cl ?N-N = (S,S)-4,4'-dibenzyl-4,5,4', 5'-tetrahydro-2,2'-bisoxazoline (S,S-4a) and NaBAr(4) ?Ar = 3, 5-C(6)H(3)(CF(3))(2) (5 mol %) catalyzed the asymmetric cyclization/hydrosilylation of dimethyl diallylmalonate (2) and triethylsilane at -30 degrees C for 48 h to form an 8.1:1 mixture of the silylated carbocycle (S,S)-trans-1, 1-dicarbomethoxy-4-methyl-3-?(triethylsilyl)methylcyclop ent ane (S, S-3) (95% de, 72% ee) and dimethyl 3,4-dimethylcyclopentane-1, 1-dicarboxylate (S,S-6) in 64% combined yield. In comparison, a 1:1 mixture of the palladium pyridine-oxazoline complex (N-N)Pd(Me)Cl ?N-N = (R)-(+)-4-isopropyl-2-(2-pyridinyl)-2-oxazoline (R-5b) and NaBAr(4) (5 mol %) catalyzed the asymmetric cyclization/hydrosilylation of 2 and triethylsilane at -32 degrees C for 24 h to form carbocycle S,S-3 in 82% yield (>95% de, 87% ee) as the exclusive product. Asymmetric diene cyclization catalyzed by complex R-5b was compatible with a range of functional groups and produced carbocycles with up to 91% ee. The procedure also tolerated substitution at a terminal olefinic position and at the allylic position of the diene.     

聚丙烯酸钠吸收释放氮肥性能

研究了聚丙烯酸钠(PAANa)吸液率及其对氮肥的吸收释放性能。结果表明,尿素对PAANa吸液率没有影响,氯化铵使其吸液率大大降低,且浓度越大吸液率越小;PAANa对不同浓度尿素溶液的吸液率均为370 g/g,对质量浓度为5、10、15和20 g/L氯化铵溶液的吸液率分别为82、62、56和55 g/g。在尿素溶液中,分配系数(mkd)约为1,而在氯化铵溶液中,mkd>1,随着氯化铵浓度增大mkd减小;PAANa对尿素没有富集作用,对NH4 有富集作用;但PAANa对尿素的吸收容量约为NH4 的10倍。PAANa对吸收的尿素和NH4 均具有缓慢释放性能,在水中经4次浸泡(24 h/次),尿素和NH4 累积释放率分别在80%和60%左右;FT-IR分析表明,NH4 与树脂中阳离子发生了离子交换。     

NH4Cl和HCl溶液浸取电石渣制备多晶型CaCO3

以电石渣为原料,分别以NH4Cl溶液和HCl溶液为浸取剂提取电石渣中的钙,以NH4HCO3为碳化剂制备CaCO3。研究了两种浸取工艺对电石渣中Ca^2+离子提取率的影响,并对两种体系浸取得到的Ca^2+离子提取率、二次残渣量和滤液中的杂质情况,以及制得的CaCO3的产率和性状进行了比较。结果表明,在浸取时间为30 min,浸取剂浓度为2.5 mol·L^-1,pH为8的条件下,以NH4Cl溶液浸取电石渣,加入量按Cl^-/Ca^2+物质的量比为2.0,得到Ca^2+离子提取率为92.87%;以HCl溶液浸取电石渣,加入量按Cl-/Ca^2+物质的量比为2.2,得到Ca^2+离子提取率为98.65%。Ca^2+离子滤液中的主要杂质通过调节pH均可以得到有效控制。NH4Cl溶液浸取电石渣Ca^2+离子提取率略低,二次残渣量高(22.39%),制得CaCO3的产率为1.065 g·g^-1电石渣;HCl溶液浸取电石渣Ca^2+离子提取率高,二次残渣量小(8.87%),制得CaCO3的产率为1.203 g·g^-1电石渣。两种浸取液碳化后制得的CaCO3产品纯度都在99%以上,白度在92.2-97.1%之间,通过控制碳化条件均可制得方解石型、球霰石型和文石型三种晶型的CaCO3。     

Analysis of the effects of N-substituents on some aspects of the aromaticity of imidazoles and pyrazoles

The influence of the N-substituent on the aromaticity of azoles is a subject that has not yet been addressed in detail, in contrast to the good understanding of the corresponding C-substitution. In the present work, we analyze the aromaticities of a series of 1,2- and 1,3-azoles (pyrazoles and imidazoles, respectively) with the N-substituents NH(2), OH, Cl, SH, H, NO(2), CN, SO(2)F, SO(2)CF(3), and N(SO(2)CF(3))(2), which are also compared with the aromaticities of the corresponding substituted benzene series. The larger stabilitiy of the imidazole ring is due not to a higher aromaticity, but rather to the weakness of the N-N bond in the pyrazole series. The aromaticity of azoles was found to be significantly less robust to N-substitutions than that of their C-substituted benzene counterparts.     

三元体系NH4Cl-SbCl3-HOAc(25℃)的研究

本文测定了三元体系NH4Cl-SbCl3-HOAc在25℃时平衡态和介稳态的溶度及部分饱和溶液的折光指数, 并绘制了相应的溶度图. 体系在稳定平衡态时有五种固相: NH4Cl、SbCl3(原始盐), 5NH4Cl-SbCl3(1)、2NH4Cl-SbCl3.5HOAc(2)和5NH4Cl-3SbCl3.2.5HOAc(3)(复盐). 一支介稳溶度曲线所对应的固相是3NH4Cl.SbCl3(4). 本文初步描述了以上四种复盐的一些物理化学性质. 体系中合成的二元复盐1和溶剂合复盐2与3文献中均未见报道. 本文提供了一种制备3NH4Cl.SbCl3的新方法.     

改性H-MOR沸石催化甲醇转化(英文)

The conversion of methanol was carried out over various mordenite zeolite catalysts to evaluate their catalytic performance. A post-preparation treatment of the H-MOR catalyst by halogenation with NH4Cl or NH4F and by hydrohalogenation with HCl or HF was carried out and its effect on methanol conversion reactions at 100–300 °C in a continuous flow reactor was investigated. The as-synthesized Hmordenite (H-MOR) is generally more active during dimethyl ether (DME) production than the NH4-MOR and Na-MOR. Fluor...