氢键链质子接受能力对质子转移反应影响的理论研究

采用密度泛函B3LYP方法,6-311+g(d,p)基组,对甲酸与质子性溶剂分子形成的HCOOH-S_1-S_2(S_1和S_2分别为H_2O和NHF2)复合物在气相时发生的基态三质子转移反应过程进行了理论研究.4个甲酸复合物HCOOH-H_2O-H_2O,HCOOH-NHF2-NHF2,HCOOH-H_2O-NHF2及HCOOH-NHF2-H_2O中发生的三质子转移反应都是以异步协同质子迁移方式进行的.甲酸复合物中的氢键链组成和连接方式对基态三质子转移反应能垒有显著影响.HCOOH-S_1-S_2复合物中氢键链的质子接受能力可以表示为a×β1+b×β2(a+b=1).当a=0.45,b=0.55时,HCOOH-S_1-S_2中氢键链的质子接受能力和HCOOH-S_1-S_2复合物中的质子转移反应能垒成线性关系.氢键链的质子接收能力越强,反应能垒越低.     

n(H_2O)(n=1,2)在HO_2+NO→HNO_3反应中的催化机制研究

采用CCSD(T)/aug-cc-p VTZ//B3LYP/6-311+G(2df,2p)方法对n(H_2O)(n=0,1,2)参与HO_2+NO→HNO_3反应的微观机理和速率常数进行了研究.结果表明,由于水分子与HO_2形成的复合物(H_2O…HO_2,HO_2…H_2O)结合NO与水分子形成的复合物(NO…H_2O,ON…H_2O)的反应方式具有较高能垒和较低有效速率,其对HO_2+NO→HNO_3反应的影响远小于双体水(H_2O)2与HO_2(或NO)形成复合物然后再与另一分子反应物NO(或HO_2)的反应方式,因此n(H_2O)(n=1,2)催化HO_2+NO→HNO_3反应主要经历了HO_2…(H_2O)_n(n=1,2)+NO和NO…(H_2O)_n(n=1,2)+HO_22种反应类型.由于HO_2…(H_2O)_n(n=1,2)+NO反应的低能垒和高速率,HO_2…(H_2O)_n(n=1,2)+NO反应优于NO…(H_2O)_n(n=1,2)+HO_2反应.与此同时,由于计算温度范围内HO_2…H_2O+NO反应的有效速率常数比HO_2…(H_2O)2+NO反应对应的有效速率常数大了10~12数量级,可推测(H_2O)_n(n=1,2)催化HO_2+NO→HNO_3反应主要来自于单个水分子.此外,在216.7~298.6 K范围内水分子对HO_2+NO→HNO_3反应起显著的正催化作用,且随温度的升高有明显增大的趋势,在298.2 K时增强因子k'RW1/ktotal达到67.93%,表明在实际大气环境中水蒸气对HO_2+NO→HNO_3反应具有显著影响.     

三重桥氧三核铁脂肪酸配合物FAB和EI质谱研究

本文报道三重桥氧三核铁脂肪酸配合物[Fe_3(μ_3～O)(μ-O_2CR)_6(H_2O)]_3~+(R=CH_3,C_2H_5,C_3H_7,C_4H_9,C_(15)H_(31)和C_(17)H_(35))的快原子轰击(FAB)和电子轰击(EI)质谱。在FAB—MS谱中观察到四种系列离子:Ⅰ.[Fe_3O(O_2CR)_n]~+n=2-6;Ⅱ.[Fe_3O(O_2CR)_nO]~+n=1-4;Ⅲ.[Fe_2O(O_2CR)_n]~+n=1-3;Ⅳ.[Fe_2(O_2CR)_n]~+n=2-4;以及与底物所形成的加合离子[Fe_3O(O_2CR)_n·NBA-1]~+n=3-5(NBA是间-硝基苄醇)。在EI—MS谱中,除上述Ⅰ—Ⅳ离子(其中n的数目略有差异)外,还观察到含三个配位水的完整阳离子[Fe_3(O_2CR)_6(H_2O)_3]~+及其与配体羧酸的加合离子[Fe_3O(0_2CR)_n(H_20)_3·RCOOH+H]~+n=4-6,(Fe_3O(O_2CR)_nO(H_2O)3·RCOOH+H]~+n=2—4和Fe(O_2CR)_n]~+n=1—3。分析了它们的断裂规律,探讨了从中所获得的有益启示。     

4-甲基-1,2,3-噻二唑-5-甲酸构筑的一维稀土配位聚合物的合成与晶体结构

由4-甲基-1,2,3-噻二唑-5-甲酸(HL,C_4H_4N_2O_2S)和相应的稀土硝酸盐Ln(NO_3)3·n H_2O(Ln=Tb,Dy,Ho,Yb)合成了4个一维稀土配位聚合物{[Ln(L)_3(H_2O)2]·H_2O}_n(Ln=Tb,1;Dy,2;Ho,3;Yb,4),均得到单晶,用元素分析、红外光谱、热重分析和X射线单晶衍射确定了产物的组成和结构。结构分析表明:4种晶体属于异质同晶型,同属于三斜晶系,空间群为Pī。每个中心金属离子Ln(III)与5个噻二唑甲酸根中的6个羧基氧原子和2个配位水分子上的两个O原子配位,配位数为8,形成一个三角十二面配位多面体。     

质子转移反应质谱用于痕量挥发性有机化合物的在线分析

质子转移反应质谱(PTR-MS)是一种化学电离源质谱技术,专门用于痕量挥发性有机化合物(VOCs)实时在线检测.此技术利用H3O-作化学电离源试剂离子与作为质子接受体的VOCs发生质子转移反应.大气中的O2,N1,CO2等主要成分由于其质子亲和势低于H2O,而不与H3O发生质子转移反应,因此可在大气环境下检测痕量VOC...     

(HAINH)_n(n=1～6)簇的结构、红外光谱和热力学性质的研究

用自洽场理论(HF)和密度泛函理论(DET)的B3LYP方法,在6-31G~μ水平上研究了HAINH的低聚物(HAINH)_n(n=1～6)簇的几何构型、电子结构、红外光谱和化学热力学性质,并比较了(HAINH)_n和(CIAINH)_n两种低聚物对应结构中化学键强弱,分析了引起(AIN)_n骨架结构发生变化的原因.结果表明,(HAINH)_n簇的基态结构为C_8(n=1),D_(2h)(n=2),D_(3h)(n=3),T_d(n=4),C_s(n=5)和D_(3d)(n=6)对称点群.HAINH基态结构中,AI-N键是三重键.在D_(2h)(n=2)和D_(3h)(n=3)结构中,所有AI-N键均为二重键.在Td(n=4)和D_(3d)(n=6)中,AI-N键为正常单键,而在C_s(n=5)结构中含有三种AI-N键:单键、双键和混合键.振动频率计算表明,结构a～f均为基态稳定结构.热力学计算给出的稳定性顺序为:f>d>e>c>b>a.     

Hydrothermal Syntheses and Crystal Structures of Six Complexes Constructed from 1,3,5-Benzenetricarboxylic Acid and 4?-(4-Pyridyl)-2,2?:6?,2??-terpyridine Mixed Ligands

Six new transition metal complexes, [Zn(HBTC)(PYTPY)]_n·n PYTPY(1), [Cu(HBTC)(PYTPY)]_n·n PYTPY(2), [Co(HBTC)(PYTPY)]_n·n DMF(3), [Mn(HBTC)(PYTPY)]_n·n DMF(4), [Cd(HBTC)(PYTPY)(H2O)]_n·2nH_2O(5), and [Co(HBTC)(PYTPY)(H_2O)_2](6),(H_3BTC = 1,3,5-benzenetricarboxylic acid, PYTPY = 4?-(4-pyridyl)-2,2?:6?,2??-terpyridine, DMF = N,N?-dimethylformamide), have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Complexes 1~5 all feature one-dimensional chain structures, and complex 6 exhibits a zero-dimensional structure. Complexes 1~5 present three-dimensional(3D) supramolecular frameworks via π-π stacking interactions, whenas 6 has also a 3D supramolecular structure assembled by hydrogen bonding. Meanwhile, complexes 1 ~ 6 exhibit the thermal stabilities and photoluminescent properties.     

基于N-3-吡啶磺酰化氨基乙酸配体的Co(Ⅱ)配位聚合物的合成、晶体结构和磁性分析（英文）

Co(OAc)_2·2H_2O,4,4′-偶氮吡啶(4,4′-azpy)和N-3-吡啶磺酰化氨基乙酸(H_2L)在乙醇和水混合溶液中反应生成了一个单核钴配位聚合物{[Co(L)(4,4′-azpy)(H_2O)]·2H_2O}_n(1)。利用元素分析、IR、热重和单晶X射线衍射对其结构进行分析。结果表明该配位聚合物属于单斜晶系,P2_1/n空间群。热重分析结果表明,配位聚合物在失去配位水分子和游离水分子后结构仍然保持不变,并在238℃开始分解,具有良好的稳定性。磁性测试表明在配合物的中心离子Co(Ⅱ)之间存在反铁磁相互作用。     

Syntheses,Structures, and Properties of Two Cobalt(Ⅱ) Coordination Complexes Based on(Fluorene-9,9-diyl) dipropanoic Acid and 1,3-Bis(imidazol-1-yl)butane Ligands

Two new cobalt(II) coordination complexes, namely [Co(HL)_2(biim)(H_2O)_2]_n·n H_2O(1) and [Co(Et L)_2(biim)]_n·3 n(H_2O)·2 n(Et HL)(2)(H_2L =(fluorene-9,9-diyl)dipropanoic acid, biim = 1,3-bis(imidazol-1-yl)butane), have been synthesized using the same starting reactants but different solvent medium. The two complexes exhibit distinctly different structures. Compound 1 exhibits a one-dimensional linear chain structure. However, complex 2 reveals a one-dimensional zigzag chain structure. Thermogravimetric analyses(TGA) and luminescent properties of these two complexes have been discussed.     

Synthesis,Structure, and Magnetic and Luminescent Properties of Rare Earth Coordination Polymers Constructed from Mixed Dicarboxylates

Three unique metal-organic framework coordination polymers, [Eu_2(bptc)(bdc)_2(H_2O)]_n(1), [Gd_2(bptc)(bdc)_2(H_2O)_4]_n(2) and [Dy_2(bptc)(bdc)_2(H_2O)_4]n(3)(1,2-H_2 BDC = 1,2-benzenedicarboylic acid, H_2 bptc = 4,4?-biphenyldicarboxylic acid) were synthesized by mixing two different multi-carboxylic acids with Ln2 O3(Ln = Eu, Gd and Dy) in hydrothermal condition. The three compounds are all three-dimensional and compounds 2 and 3 contain 4.289 × 6.507 ?~2 rectangularshaped one-dimensional open channels along the a direction. Additionally, the magnetic, luminescent and thermogravimetric properties were studied in detail.     

Structural Diversity and Luminescent Properties of Metal-organic Frameworks Based on a Rare Sulfonate and Imidazole Co-Ligand System

Four types of luminescent properties of metal-organic frameworks(MOFs) with formulas [Cd(1,2-BIYB)2(H_2O)_2]_n·n(AQ-1,5-DAD)(1), [Cd(AQ-1,5-DAD)(1,3-BIYB)_2]_n(2), [Cd(1,3-BIYB)]n·n(AQ-1,5-DAD)·n H_2O(3), and [Zn(1,4-BIYB)_2]_n·n(AQ-1,5-DAD)2·6H_2O(4),(Na_2AQ-1,5-DAD = anthraquinone-1,5-disulfonic acid disodium, 1,2-BIYB = 1,2-bis(imidazol-1-ylmethyl)benzene, 1,3-BIYB = 1,3-bis(imidazol-1-ylmethyl)benzene, 1,4-BIYB = 1,4-bis(imidazol-1-ylmethyl)benzene) have been synthesized based on a rare sulfonate and imidazole Co-ligand system under different conditions. The structural features of four types of MOFs 1~4 are as follows: MOFs 1 show a 3D supramolecular compound in which the double one-dimensional chains are further cross-linked by hydrogen bonds. 2 exhibits a 2D network constructed by two different 1D chains. 3 features a 2D supramolecular network, in which the 1D chains and AQ-1,5-DAD are arranged alternately through hydrogen bonds. 4 posseses a 3D supramolecular structure constructed by a 2D network and one-dimensional hydrogen bonding chains. All compounds 1~4 are characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The luminescence properties of 1~4 have been investigated.     

B型DNA中鸟嘌呤-胞嘧啶碱基对内双质子转移反应

采用ONIOM(M06-2X/6-31G^*:PM3)方法研究了单个鸟嘌呤-胞嘧啶(GC)碱基对和含GC碱基对的四种排序的DNA三聚体(dATGCAT, dGCGCGC, dTAGCTA, dCGGCCG)的双质子转移反应. 通过分析其双质子转移方式、质子转移过程中各结构的能量和氢键变化, 总结出环境因素对GC碱基对双质子转移机理的影响. 气相中, dCGGCCG三聚体中发生分步双质子转移, 其它四种模型中均发生协同双质子转移. 分析发现质子转移方式受上下相邻碱基对的静电相互作用和质子接受位的质子亲和势影响, dATGCAT和dGCGCGC排序有助于质子H4a转移, 而dTAGCTA和dCGGCCG排序有助于质子H1转移, 胞嘧啶的N3位较高的质子亲和势有助于质子H1转移. 水溶剂中, 上下相邻碱基对的静电相互作用被减弱, 水溶剂稳定了分步转移过程中的单质子转移产物, 因此分步转移机理占据优势, 五种模型中均出现分步双质子转移, 在此过程中能量变化趋势相似. 溶剂效应有利于单质子转移, 却增加了双质子转移反应的反应能.     

基于半刚性双(噻唑基苯并咪唑)和不同羧酸的五个一维配合物的合成和表征

通过水热或溶剂热合成的方法制备了5个一维配合物{[Zn(btbb)_(0.5)(m-phda)]·0.5H_2O}_n(1),{[Cd_2(btbb)(adtda)_2(H_2O)]·H_2O}_n(2),[Mn_2(btbb)(tbi)_2]_n(3),{[Cd(btbb)_(0.5)(3-Nitro-o-bdc)(H_2O)]·H_2O}_n(4)和[Cd_2(btbb)(tbi)_2]_n(5)(btbb=1,4-双(2-(4-噻唑基)苯并咪唑-1-基甲基)苯,m-H_2phda=间苯二甲酸,H_2adtda=1,3-金刚烷二羧酸,H_2tbi=5-叔丁基间苯二甲酸,3-Nitro-o-H_2bdc=3-硝基-1,2-苯二甲酸)。配合物1是一个包含22元环的一维链。配合物2是一个包含8元环的一维链,并且氮配体在这个一维链中仅仅起到装饰作用。配合物3是一个一维双链结构。配合物4是一个包含14元环的一维链。配合物5是一个阶梯状的一维双链结构。     

Aromatic Multicarboxylate Ligands Tuned One-and Three-dimensional Zn(Ⅱ) Coordination Polymers Based on 3-(1H-pyrazol-4-yl)-5-(pyridin-3-yl)-1,2,4-triazole

Two aromatic multicarboxylate ligands tuned Zn(Ⅱ) coordination polymers, namely, {[Zn_(0.5)(H_2L)(tp)_(0.5)(H_2O)]H_2O}_n(1) and {[Zn_2(HL)(btc)(H_2O)]H_2O}_n(2)(H_2L = 3-(1 Hpyrazol-4-yl)-5-(pyridin-3-yl)-1,2,4-triazole, H_2tp = terephthalic acid; H_3 btc = 1,3,5-benzenetricarboxylic) have been synthesized. Their structures were characterized by single-crystal X-ray diffraction analysis, elemental analyses and infrared spectra. Compound 1 possesses a one-dimensional chain structure and is finally extended into a three-dimensional supramolecular architecture though hydrogen bonding interactions. Compound 2 shows a three-dimensional framework. Meanwhile, compounds 1 and 2 exhibit luminescent emission in the solid, and can be investigated as potential luminescent materials.     

Three New Isostructural Metal-organic Coordination Polymers from Triangular Pyridinedicarboxylate Ligand:Syntheses,Structures and Properties

Three new isostructural coordination polymers, namely, [Mg(cpna)(H_2O)_2]_n(1), [Mn(cpna)(H_2O)_2]_n(2) and [Co(cpna)(H_2O)_2]_n(3)(H_2 cpna = 5-(3-carboxylphenyl)nicotic acid) are reported. They were synthesized by hydrothermal reactions of transition metal or alkaline earth metal chloride with 5-(3-carboxylphenyl)nicotic acid,respectively. Complexes 1～3 exhibit 2D layers with a 3,3-connected topology with Schl?fli symbol {4.82}. Such layers including hexagonal rings and a quadrangular ring are further extended into an ordered 3D framework by hydrogen bonds between the cpna~(2-) ligands and water molecules. The rare complex 1 has excellent luminescence and can be used as luminescent materials, while 2 and 3 possess prominent magnetism with potential applications in magnetic materials.     

基于异噁唑酮类份菁染料的激发态分子内质子转移的研究

运用量子化学理论计算方法研究了3-甲基-4-(1H-吲哚-3-次甲基)-异噁唑-5-酮(A)及其衍生物份菁染料的激发态分子内质子转移性质.研究表明:在基态3种染料AH(R=H),AO(R=—O(H3))和AP(R=—O(H2Ph))只存在酮式构型,在激发态AH与AP存在酮式和烯醇式2种构型,而AO存在酮式、烯醇式和仲胺式3种构型.红外光谱表明化合物从基态跃迁到激发态存在分子内的氢键增强作用,势能曲线显示激发态的质子转移为放热反应且能垒较低,通过分析电子光谱得到具有较大斯托克位移的激发态分子内质子转移的荧光发射峰,前线分子轨道理论计算进一步说明了其质子转移的发生过程.     

以1,2,4,5-苯四甲酸或1,2,3,4-丁烷四羧酸为配体的金属有机框架的合成、表征及性质

以1,2,4,5-苯四甲酸(H_4BETA)与1,2,3,4-丁烷四羧酸(H_4BTCA)为有机配体,采用溶剂热法,成功合成了3个金属有机框架(Metal-Organic Frameworks,MOFs):{[Co_5(BETA)_2(OH)_2(H_2O)_2]·10H_2O}_n(1)、{[Zn_5(BETA)_2(OH)_2(H_2O)_2]·10H_2O}_n(2)和{[Mn_2(BTCA)(H_2O)_3]·H_2O}_n(3),并利用X射线单晶衍射、红外光谱(IR)、荧光光谱(PL)和热重分析(TG/DTG)等测试手段对其进行了表征。单晶结构研究表明3个MOFs均属于单斜晶系,P21/n空间群;框架1和2都是由1,2,4,5-苯四甲酸与五核的金属簇连接形成三维框架结构,沿a轴方向具有一维孔道结构,孔径大小为0.990 nm×1.307 nm;框架3是由1,2,3,4-丁烷四羧酸与Mn~(2+)连接形成4,8-c网络的三维框架结构。     

水环境对GC和AT碱基对质子转移的影响

采用B3LYP/DZP++的方法研究了第一水化层作用和连续化处理的水溶剂作用对鸟嘌呤-胞嘧啶(GC)碱基对和腺嘌呤-胸腺嘧啶(AT)碱基对质子转移反应的影响.GC和AT碱基对在连续化水溶剂作用下,均发生单质子转移(SPT1)和分步的双质子转移(DPT),而在第一水化层5个水分子的作用下(GC·5H2O,AT·5H2O)或同时考虑第一水化层作用和连续化水溶剂作用(GC·5H2O+PCM,AT·5H2O+PCM)时,GC和AT碱基对的质子转移均只得到单质子转移反应(SPT1).单质子转移过程中的活化能变化情况表明:第一水化层对GC和AT碱基对结构和质子转移影响较大,水环境对碱基对的作用主要发生在第一水化层.     

3,5-二(吡啶-4-甲氧基)苯甲酸和芳香二羧酸配体构建的具有3,4-连接四重和三重穿插的d~(10)金属配位聚合物（英文）

以3,5-二(吡啶-4-甲氧基)苯甲酸(HL)与芳香二羧酸为配体,在水热条件下与Zn(Ⅱ)或Cd(Ⅱ)盐反应得到4个具有3,4-连接多重穿插结构的配位聚合物:[Zn_2L_2(tdc)]_n(1),{[Zn_4L_4(Hhdc)_2]·H_2O}n(2),{[Zn_2L_2(Hhdc)]·H_2O}n(3),{[Cd_2L_2(bdtc)(H_2O)]·0.5H_2O}n(4)(H_2tdc=2,5-噻吩二甲酸,H_3hdc=5-羟基间苯二甲酸,H_2bdtc=1,4-苯二硫乙酸)。晶体结构分析表明,聚合物1~3具有3,4-连接四重穿插的三维网络结构,拓扑符号分别为(4.82)(4.85)(1)、(63)(65.8)(2)和(63)(65.8)(3)。4为3,4-连接三重穿插的二维平面结构,拓扑符号为(6~3)(6~6)。测定了配位聚合物1、3和4的热稳定性和荧光性质。     

(H_2O)_n(n=0～2)催化HS和HOCl反应机理的理论研究

在CCSD(T)/6-311+G(3df,2p)//M06-2X/6-311+G(3df,2p)水平上研究了(H_2O)n(n=0~2)催化HS和HOCl的反应机理.结果表明,HS与HOCl反应中HS夺取HOCl上的H原子形成产物H_2S和ClO.在无水催化时,该反应存在2种不同的路径(分别经过过渡态TS1和TS2,二者互为顺反结构),对应的能垒分别为100.28和100.91kJ/mol,到达产物(H_2S+ClO)需吸收18.99kJ/mol能量,反应不易发生;在单个水分子参与时,水分子可通过形成弱相互作用或者作为H原子转移桥梁影响反应机理,获得了4种水催化路径,能垒(间于53.97~92.39kJ/mol之间)均低于无水催化过程.同时发现,在反应到达产物前,水分子可以与产物形成中间体IM,IM相对能仅为0.46kJ/mol,有利于产物形成;有2个水分子参与反应时,找到了3条催化路径,最优反应路径过渡态TS7的能垒为45.05kJ/mol,低于无水催化过程,相比单个水分子最优路径能垒(53.97kJ/mol)并无显著降低.