硼-锗骨架无机微孔材料研究进展

作为潜在的新型功能材料，硼-锗骨架微孔化合物近年来得到科学家的普遍关注。本文从结构化学的角度，分别讨论了硼酸盐、锗酸盐及硼锗酸盐研究体系，并对其中的典型结构进行了描述、归类与总结；针对硼、锗易成簇聚集的特点，探讨了硼-锗骨架无机微孔化合物研究的发展趋势。     

α—和β—三钒九钨锗酸钾的合成和表征

合成了α-和β-三钒九钨锗酸钾,并用元素分析、红外光谱和紫外光谱、~(51)V和~(183)W核磁共振、极谱和循环伏安、热分析及单晶衍射等方法进行了表征。结果表明,这些新化合物具有与GeW_(12)相似的结构;3个钒原子属于不同的M_3O_(13)单元且彼此共角相连。与钨锗酸盐相比,三钒取代的钨钒锗酸钾的热稳定性降低而氧化性增强。     

两种基于B5On(n=11, 12)簇构筑的具有深紫外吸收的硼酸盐

以碱金属和碱土金属为模板, 在溶剂热条件下合成了两种具有深紫外吸收特性的硼酸盐Na₂Ba· [B₅O₈(OH)]₂·2H₂O(1)和KSr[B₅O₈(OH)₂](2), 并利用单晶X射线衍射(SCXRD)、 粉末X射线衍射(PXRD)、 傅里叶变换红外(FTIR)光谱、 紫外-可见吸收光谱(UV-Vis)和热重分析(TG)等手段对化合物的结构和性能进行了研究. 结果表明, 化合物1可归属于单斜晶系P2/c空间群, 结构中四连接的B₅O₁₀(OH)簇单元通过共氧连接形成含有两种9-元环窗口的二维层; 化合物2结晶于单斜晶系C2/c空间群, 结构中四连接的B₅O₁₀(OH)₂簇单元则通过共氧交替连接构筑了罕见的含有8-/12-元环孔道的二维褶皱层. 两种基于B₅O_n(n=11, 12)簇单元构筑的化合物均具有低于200 nm的深紫外吸收边, 在紫外/深紫外区具有潜在的应用价值.     

新型层状氟化磷酸铝[C4H12N2][Al2(PO4)2(H2O)2F2]的水热合成与表征

自从1982年Wilson等发现一类新型微孔材料磷酸铝分子筛(AlPO4-n)以来,大量具有新颖结构的磷酸铝化合物被合成出来,它们在催化、离子交换、吸附和主-客体组装等方面均具有潜在的应用前景,这类化合物大多是在水热或溶剂热体系中和有机模板剂存在条件下合成的,1978年,Flanigen等首先在反应体系中加入氟离子作矿化剂合成了硅晶体,后来,氟离子方法在硅铝体系和金属磷酸盐体系中也得到了广泛的应用,氟离子在反应过程中起到矿化剂或结构导向剂的作用,     

链状Cs_8Mn_4Sn_4Se_(16)和[Ni(1,2-dap)_3]_2Cd_2Sn_2S_8(1,2-dap:1,2-丙二胺)的溶剂热合成与表征

采用溶剂热法,在1,4-丁二胺中合成以碱金属为客体阳离子的硫属锡酸盐Cs_8Mn_4Sn_4Se_(16)(1)及1,2-丙二胺(1,2-dap)配位的过渡金属为客体阳离子的硫属锡酸盐[Ni(1,2-dap)_3]_2Cd_2Sn_2S_8(2)。并采用单晶X射线、紫外可见漫反射、热重分析-差示扫描量热分析(TG-DSC)等手段进行表征。结果表明,化合物1为正交晶系,空间群为Fddd;化合物2为正交晶系,空间群为Cmcm;且结构中均包含Sn Q4(Q=S,Se)四面体与TMQ_4(TM=Mn,Cd)四面体通过共边而成的一维(1-D)阴离子链,紫外可见漫反射分析表明,化合物1、2的禁带宽度分别为1.70和2.21 e V,具有半导体性质。且TG-DSC测试显示化合物1、2在一定温度下具有一定的稳定性。     

樟脑酸衍生物构筑的单一手性金属有机骨架化合物的合成、表征及荧光性质

设计合成了一个新的手性樟脑酸衍生物[D-H₂ctba, H₂ctba=4-(3-羧基-2,2,3-三甲基环戊烷酰胺)苯甲酸]. 将其作为配体与硝酸镉通过溶剂热反应得到了新的手性金属有机骨架化合物[Cd₃(ctba)₃·H₂O]_n(1). 通过单晶X射线衍射(XRD)、 粉末X射线衍射(PXRD)、 元素分析、 热重分析(TGA)和圆二色(CD)光谱对该化合物进行了表征. 单晶结构解析表明, 该化合物具有单一手性结构, 以1个六核的Cd羧基簇为基本单元, 簇与簇之间通过羧基相连形成(-Cd-O-C-)_∞棒状次级结构单元, 次级结构单元之间由配体相连, 拓展成为三维的骨架结构. 荧光光谱测试结果表明, 该化合物在室温下具有较强的荧光性质.     

具有四帽假Keggin结构“簇阴离子对”的多金属氧簇[Co(2,2-bipy)_3]_4[Mo_5~ⅤMo_5~ⅥV_6~ⅣO_(40)(PO_4)]_2·4H_2O的水热合成与晶体结构

金属 -氧簇合物在催化、医药和材料等方面的应用越来越成为无机化学研究的热点 [1～ 4 ] .在众多的金属 -氧簇合物中 ,只有几种双帽及四帽 Keggin结构被合成出来 [5～ 12 ] ,而含有四帽假 Keggin结构的钼 -钒 -氧簇合物尚未见报道 .我们用水热合成方法合成了第一个具有四帽假 Keggin结构“簇阴离子对”{Mo10 V6 O4 0 ( PO4 ) }2 的多金属氧簇 [Co( 2 ,2 - bipy) 3]4 [Mo10 V6 O4 0 ( PO4 ) ]2 · 4H2 O.该化合物是由四帽假Keggin结构“簇阴离子对”{Mo10 V6 O4 0 ( PO4 ) }2 和 4个配位阳离子 [Co( 2 ,2 - bipy) 3]2 +通过阴阳离…     

蒸汽辅助合成STW结构硅锗酸盐分子筛

采用蒸汽辅助法制备了高稳定性STW结构硅锗酸盐分子筛. 相比于传统水热方法, 使用温和的蒸汽辅助可显著减少模板剂用量, 产物结晶度与骨架Si元素含量更高. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 能量散射谱(EDS)、 热重(TG)分析等技术手段考察了蒸汽辅助合成硅锗酸盐分子筛过程中水对产物结构的影响, 发现随着外加水量的增加, 产物从纯相GeO₂逐渐转化为STW分子筛纯相, 最终变为GeO₂, STW与MFI结构的混相; 此外, 反应物中带入的痕量水可以优先活化Ge元素, 从而在一定程度上决定了产物构型.     

含有不同配位阳离子的四帽Keggin结构砷钼钒酸盐[Co(en)3][Co(en)2(H2O)2]2@[Mov4MoⅥ4VⅣ8O40(AsO4)]的合成与结构

多金属氧酸盐在催化、医药和材料等方面的应用越来越成为无机化学研究的热点[1～5].水热合成技术在合成多核金属氧酸盐中有独特的优点.在众多的钼钒酸盐中,只有几种双帽及四帽Keggin结构被合成出来[6～13].本文报道一种含有不同配位阳离子的四帽Keggin结构砷钼钒酸盐[Co(en)3]·[Co(en)2(H2O)2]2·[Mov4MoⅥ4VⅣ8O40(AsO4)]的合成与结构.该化合物的结构是由不同的阳离子--1个[Co(en)3]3+和2个[Co(en)2(H2O)2]2+及簇阴离子[Mov4MoⅥ4VⅣ8O40(AsO4)]5-构成的.[Mo8V8O40(AsO4)]5-簇阴离子具有四帽"Keggin"结构,两对V原子位于4个"双帽"位置,簇笼中央是1个{AsO4}四面体.     

羧酸根阴离子型功能化离子液体对纤维素的溶解性能

通过两步法合成了1,3-二甲基咪唑乙酸盐([C₁mim][CH₃COO])和1,3-二甲基咪唑羟基乙酸盐([C₁mim][HOCH₂COO])两种羧酸根阴离子型功能化离子液体。 研究了纤维素在这两种离子液体中的溶解性能。 结果表明,阴离子的结构对纤维素的溶解性能有明显影响,在120 ℃下,两种离子液体对纤维素的溶解度分别为19.7%和21.2%。 通过傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)以及热重分析(TG)等技术手段对再生纤维素的结构和热稳定性进行表征,表明两种离子液体均为纤维素的直接溶剂,纤维素在溶解及再生过程中晶体结构由I型转变为无定型结构,且热稳定性有所下降。 此外,研究发现溶解温度的提高和溶解时间的延长均会导致再生纤维素聚合度的降低。 所获得的研究结果为纤维素溶剂体系的开发具有指导意义。     

GeO2 natrolite-type infinite four and eight R-containing layers in a 2D pure-Ge framework: Ge3O5(OH)4[C2N2H10

A new two-dimensional framework germanate, Ge3O5(OH)4[C2N2H10] (denoted ICMM-8), with a 3:9 Ge:O ratio has been synthesized, using a mixture of pyridine, water, and ethanol as the solvent and 1,4-diazabicyclo[2.2.2]octane and ethylenediamine as the structure-directing agents, under solvothermal conditions. The structure was determined by single-crystal X-ray diffraction. In this new compound, the GeO2 natrolite-type infinite four and eight R-containing layers appears for the first time in a pure GeO2 framework. The total 2D structure is built up from SBU-6, four tetrahedra, and two octahedra. The hydroxyl groups occupy four positions of each octahedral germanium atom. The compound is characterized by IR spectra and TGA-DTA. Crystal data: Ge3O5(OH)4[C2N2H10], monoclinic space group P2(1)/c; a = 11.3570(9) Angstroms, b = 8.8819(7) Angstroms, c = 9.9200(8) Angstroms, beta = 90.710(1), V = 1000.6(1) Angstroms(3), Z = 4, R(1) = 0.044 (I > 2(I)), and wR(2) = 0.1051 (all data).     

Synthesis, structure, and upconversion studies on organically templated uranium phosphites

Three new amine templated uranium phosphites, [C2N2H10][U2IVF6(HPO3)2], 1, [C4N2H12][U2IVF6(HPO3)2], 2, and [C4N2H12][(UVIO2)2F2(HPO3)2], 3, have been synthesized by hydrothermal methods. All of the compounds are built up from a connectivity between U(O/F)x (x = 7, 8) and HPO3 polyhedral units. The observation of a well-established secondary building unit, SBU-4, in 1 and 2 is noteworthy. In 1, the SBU-4 units are connected to form U-F-U chains, which are linked by U-O-P chains, forming the layered structure. In 2, the SBU-4 units are edge-shared and also interconnected forming the 3D structure. In 3, the connectivity between the building units forms a layer, the topology of which is similar to the mineral, johannite. To the best of our knowledge, this is the first observation of a well-known secondary building unit (SBU-4) in actinide framework compounds. Optical studies on 1 and 2, containing U(4+) species, indicate an intense blue emission through an upconversion process, and the magnetic susceptibility studies show antiferromagnetic behavior.     

Synthesis,Structure Characterization and Photoluminescence of a Novel Complex with（6,4,4）-Network [Ce_2（2,5-pydc）_3（H_2O）_2]（2,5-pydc = Pyridine-2,5-dicarboxylic Acid）

A new three-dimensional supramolecular [Ce2(2,5-pydc)3(H2O)2](1) has been hydrothermally synthesized at 180 ℃ and characterized by single-crystal X-ray diffraction.X-ray crystal analyses reveal that the compound belongs to the monoclinic system,space group P21/c,C21H13Ce2N3O14,a = 6.561(1),b = 17.986(5),c = 9.411(3) ,β = 95.558(5)° and Z = 2.In the structure of 1,each Ce(1) center is surrounded by 2,5-pydc ligands,forming the 6-connected node,and the 2,5-pydc ligand coordinates to the Ce(Ⅲ) in two different coordination modes.In mode 1,the four oxygen atoms of two carboxyl groups connect neighboring Ce(Ⅲ) ions,giving 4-connected(4-c) second building unit(SBU-1).Furthermore,the structure is extended into a 2-D layer from SBU-1 by sharing Ce(1) atoms.In mode 2,the ligand coordinates to the Ce(Ⅲ) ion from the adjacent chain with the 4-connected(4-c) second building unit(SBU-2),generating a 1-D ladder from SBU-2 by sharing Ce(1) atoms.Finally,the structure is extended into a 6,4,4-c network.Its photoluminescence property was also investigated.     

Experimental validation of Gaussian-3 lithium cation affinities of amides: implications for the gas-phase lithium cation basicity scale.

Using a refined Gaussian-3 (G3) protocol, the highest level of ab initio calculations reported so far, we have established the Li+ cation binding enthalpy (affinity) at 0 K (in kJ mol-1) for formamide (195.7), N-methylformamide (209.2), N,N'-dimethylformamide (220.0), acetamide (211.7), N-methylacetamide (222.5), and N,N'-dimethylacetamide (230.1), with an estimated maximum uncertainty of +/-8 kJ mol-1. With these six theoretical lithium cation binding affinities as reference values, the absolute Li+ affinities of imidazole and dimethoxyethane were determined by the extended kinetic method, and by adopting the statistical data treatment protocol recently proposed by Armentrout. The Li+ affinities obtained for these two ligands are in good agreement (within 6 kJ mol-1) with recent values determined by the threshold collision-induced dissociation method, and consistent with the Li+ basicity values first reported by Taft and co-workers in 1990. Our study confirms that the previously suggested, and recently implemented, downward revision of Taft's original basicity scale by 10.9 kJ mol-1 is justified for ligands with revised basicities less than 151 kJ mol-1. However, for selected ligands with Li+ basicities greater than 151 kJ mol-1, including some of the six amides studied in this work, the reported discrepancy between theoretical and experimental estimates in the revised Li+ basicity scale of Burk et al. is likely to arise from experimental uncertainties.     

A germanium zeotype with a three-dimensional net of interconnected 14-, 12- and 12-ring channels. Ge13O26(OH)4[C6N2H16]2(H2O)1.5

Ge(13)O(26)(OH)(4)[C(6)N(2)H(16)](2)(H(2)O)(1.5) is a novel germanium zeotype built up from a new type of SBU; the SBU-13 is formed from polyhedra distributed in three shells. Its open 3D framework has a three-dimensional system of intersecting channels, where the 14-ring channels are lined with OH(-) anions.     

An experimental and theoretical study of the basicity of tetra-tert-butyltetrahedrane

The gas-phase basicity (GB) of tetra-tert-butyltetrahedrane (tBu4THD) was determined by FT-ICR mass spectrometry and comparison with reference compounds of known basicity. Its GB, 1035+/-10 kJ x mol(-1), makes tetra-tert-butyltetrahedrane one of the strongest bases reported so far. Ab initio calculations [B3LYP/6-31G(d) and B3LYP/6-311 + G(d,p)//6-31G(d)] have been carried out in order to compare the high experimental basicity of tBu4THD with that estimated theoretically. Both B3LYP/6-31G(d) and QCISD(T) calculations were used to determine the reaction path which connects the initial tetrahedrane-ammonium complex with the final products, protonated cyclobutadiene (CBDH+) and ammonia.     

锆酸钡/聚合物复合中空纳米球的水热合成

采用聚合物辅助水热合成方法, 在强碱条件下加入PAA和PVA的混合液,实现了聚合物/锆酸钡复合中空纳米球的软化学一步合成, 而且球壳为有机-无机复合材料, 有望用于吸附分离、催化剂载体、轻质陶瓷和涂料等方面.     

Inorganic-organic hybrid structures: open-framework iron phosphite-oxalates of varying dimensionality

Inorganic-organic hybrid structures belonging to the family of iron phosphite-oxalates have been prepared by employing hydrothermal methods. Their structures, determined by single-crystal X-ray diffraction, show a hierarchy within the family. While compounds I and II are low dimensional, III-VI have three-dimensional structures. Compound I has edge-shared ladders of iron phosphite with oxalate units hanging from the iron centers. Compound II has a layer structure with a honeycomb-like arrangement. The three-dimensional hybrid structures have the oxalate units connected in both in-plane and out-of-plane modes. A newly identified secondary building unit (SBU-7) and the oxalate units satisfying the valence and coordination requirements in the structure of V are novel and noteworthy structural features. Magnetic studies show that the dominant interactions between the iron centers are antiferromagnetic. Similar to other known hybrid structures, the phosphite-oxalate structures appear to show wide compositional and structural diversity.     

Cyclization of monosubstituted triaminopyrimidines with acetic acid imino ester hydrochloride

6-N-Substituted 6-amino-8-methylpurines and 6-amino-8-methyl-9-substituted purines were obtained by cyclization of 6-N-substituted 4,5,6-triaminopyrimidines with acetic acid imino ester hydrochloride. The yields of the isomers depend on the different basicities of the secondary amino groups, which are determined by the basicities of the starting amines. The yields of the 6-amino-8-methyl-9-substituted purines increase with decreasing basicity.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1432–1434, October, 1970.     

Basicity of some P1 phosphazenes in water and in aqueous surfactant solution

The pKa values in water and in dilute surfactant solution for 15 ring-substituted phenyl P1 pyrrolidino phosphazenes PhN=P(NC4H8)3 and the phenyl P1 dimethylamino phosphazene PhN=P(NMe2)3 previously studied in acetonitrile (AN) and tetrahydrofuran (THF) are reported. The nonionic surfactant Tween 20 was used for the basicity measurements of some compounds to overcome the solubility problems. Measurements with a control group of phosphazenes in both media were used to validate the use of the obtained pKa values as estimates of aqueous values. The pK(a) values of the studied phosphazenes in aqueous medium vary from 6.82 (2,6-dinitro-) to 12.00 (4-dimethylamino-). The basicity span is 5.18 pKa units. The aqueous pKa values of the P1 phosphazenes were correlated with the respective basicity data in AN and THF and from these correlations the pK(a) values in water for the parent compounds HN=P(NC4H8)3 and HN=P(NMe2)3 were estimated as 13.9 and 13.3. Also a comparison of the basicity of phosphazenes and some guanidines, amines and pyridines was made. In water the parent phosphazenes and guanidines are the strongest of all the groups of bases studied. In AN and THF the parent phosphazenes are clearly the strongest bases followed by guanidines, amines and pyridines which are bracketed between the basicities of phenyl phosphazenes. In the gas phase the phosphazenes for which data are available are clearly more basic than the other compounds referred to here. Comparison of the basicity data of P1 phosphazenes and some guanidines confirms earlier conclusions about the partly ylidic character of the N=P double bond.