Synthesis, crystal structure, and solid-state NMR spectroscopy of a new open-framework aluminophosphate (NH(4))(2)Al(4)(PO(4))(4)(HPO(4))xH(2)O

A new three-dimensional open-framework aluminophosphate (NH(4))(2)Al(4)(PO(4))(4)(HPO(4)).H(2)O (denoted AlPO-CJ19) with an Al/P ratio of 4/5 has been synthesized, using pyridine as the solvent and 2-aminopyridine as the structure-directing agent, under solvothermal conditions. The structure was determined by single-crystal X-ray diffraction and further characterized by solid-state NMR techniques. The alternation of the Al-centered polyhedra (including AlO(4), AlO(5), and AlO(6)) and the P-centered tetrahedra (including PO(4) and PO(3)OH) results in an interrupted open-framework structure with an eight-membered ring channel along the [100] direction. This is the first aluminophosphate containing three kinds of Al coordinations (AlO(4), AlO(5), and AlO(6)) with all oxygen vertexes connected to framework P atoms. (27)Al MAS NMR, (31)P MAS NMR, and (1)H --> (31)P CPMAS NMR characterizations show that the solid-state NMR techniques are an effective complement to XRD analysis for structure elucidation. Furthermore, all of the possible coordinations of Al and P in the aluminophosphates with an Al/P ratio of 4/5 are summarized. Crystal data: (NH(4))(2)Al(4)(PO(4))(4)(HPO(4))xH(2)O, monoclinic P2(1) (No. 4), a = 5.0568(3) A, b = 21.6211(18) A, c = 8.1724(4) A, beta = 91.361(4) degrees , V = 893.27(10) A(3), Z = 2, R(1) = 0.0456 (I > 2 sigma(I)), and wR(2) = 0.1051 (all data).     

Distribution of aluminum and boron in the periodical building units of boron-containing Beta zeolites

Various boron only ([B]-BEA) as well as aluminum- and boron-containing beta zeolites ([Al,B]-BEA) have been prepared and modified by ion exchange of ammonium, sodium, and nickel ions. The zeolite samples have been characterized by 11B, 27Al, and 29Si MAS as well as three of them by 11B and 27Al 3Q-MAS NMR spectroscopy. The quantitative contributions of defect-free Si(nX) (n = 2, 1, 0; X = Al, B) and Si(OH)x (x = 2, 1) sites to the NMR signal intensities were calculated from the various Si/(Al + B) ratios and relative 11B, 27Al, and 29Si NMR signal intensities using the special distribution of aluminum and boron in different periodical building units of the zeolite framework. The boron atoms are sitting exclusively in diagonal positions in the four-membered rings of [B]-BEA zeolites, while the aluminum atoms are situated both in diagonal and lone positions in the four-membered rings of [Al,B]-BEA zeolites. A higher part of boron atoms are positioned in framework-related deformed tetrahedral boron species than in lattice positions in the [B]-BEA than in the [Al,B]-BEA zeolites. All extraframework octahedral aluminum species are transformed back to lattice positions due to ion exchange from the protonated form to ammonium-, sodium-, or nickel-ions containing zeolites. Oppositely, trigonal boron leaves the zeolite structure completely during ion exchange.     

铝在MCM-22分子筛骨架上分布的27Al MQ MAS NMR研究

利用二维多量子魔角旋转（2D MQ MAS）技术并结合量子化学计算，研究了铝在MCM-22分子筛骨架上的分布，并对铝的不等价四面体位进行了归属.在27Al 2D 5Q MAS NMR谱中骨架四配位铝的范围内观察到3个信号，证明MCM-22分子筛有3种骨架铝.经计算这3种骨架四配位铝的各向同性化学位移和四极作用常数分别为：δ 50.5、δ 57.3、δ 62.4和1.74、1.68、1.92 MHz. MCM-22分子筛结构中有8种结晶学不等价四面体（T）位.我们通过模拟MCM-22分子筛的27Al 2D 5Q MAS NMR谱，认为8种不等价T位分为3组. T2、T6位上的铝分别与δ 61、δ 49处的信号相关， T1、T3、T4、T5、T7、T8位上的铝对δ 56处的共振峰有贡献.当硅铝原子数比(Si/Al)在10～15之间变化时，铝在MCM-22分子筛的骨架上是无规占据的.     

New nonlinear optical crystal: NaBa4Al2B8O18Cl3

Single crystals of NaBa(4)Al(2)B(8)O(18)Cl(3) have been grown with sizes up to 34 × 34 × 16 mm(3) from the NaF-LiCl flux by the top-seeded solution growth method. The compound crystallizes in the tetragonal system, space group P4(2)nm, with a = 12.0480 (16) ?, c = 6.8165 (11) ?, α = β = γ = 90°, and two formula units per cell. The NaBa(4)Al(2)B(8)O(18)Cl(3) compound is built up of infinite anionic groups of [AlB(4)O(12)](9-) formed by two BO(4) tetrahedra, one AlO(4) tetrahedra, and two BO(3) triangles. Optical properties including ultraviolet transmission, IR spectrum, and second-harmonic generation of NaBa(4)Al(2)B(8)O(18)Cl(3) crystals were reported. Refractive indices were measured by the minimum deviation technique and fitted to the Sellmeier equations. Thermal properties such as the DSC and thermal expansion were reported. The mechanical properties including the hardness, density, and chemical stability were also reported.     

Structural models for yttrium aluminium borate laser glasses: NMR and EPR studies of the system (Y2O3)(0.2)-(Al2O3)x-(B2O3)(0.8-x)

The structure of laser glasses in the system (Y(2)O(3))(0.2){(Al(2)O(3))(x))(B(2)O(3))(0.8-x)} (0.15 ≤ x ≤ 0.40) has been investigated by means of (11)B, (27)Al, and (89)Y solid state NMR as well as electron spin echo envelope modulation (ESEEM) of Yb-doped samples. The latter technique has been applied for the first time to an aluminoborate glass system. (11)B magic-angle spinning (MAS)-NMR spectra reveal that, while the majority of the boron atoms are three-coordinated over the entire composition region, the fraction of three-coordinated boron atoms increases significantly with increasing x. Charge balance considerations as well as (11)B NMR lineshape analyses suggest that the dominant borate species are predominantly singly charged metaborate (BO(2/2)O(-)), doubly charged pyroborate (BO(1/2)(O(-))(2)), and (at x = 0.40) triply charged orthoborate groups. As x increases along this series, the average anionic charge per trigonal borate group increases from 1.38 to 2.91. (27)Al MAS-NMR spectra show that the alumina species are present in the coordination states four, five and six, and the fraction of four-coordinated Al increases markedly with increasing x. All of the Al coordination states are in intimate contact with both the three- and the four-coordinate boron species and vice versa, as indicated by (11)B/(27)Al rotational echo double resonance (REDOR) data. These results are consistent with the formation of a homogeneous, non-segregated glass structure. (89)Y solid state NMR spectra show a significant chemical shift trend, reflecting that the second coordination sphere becomes increasingly "aluminate-like" with increasing x. This conclusion is supported by electron spin echo envelope modulation (ESEEM) data of Yb-doped glasses, which indicate that both borate and aluminate species participate in the medium range structure of the rare-earth ions, consistent with a random spatial distribution of the glass components.     

层状磷酸铝UT-4的固体核磁共振研究

用吡啶代替四乙二醇作为溶剂, 在Al2O3-H3PO4-C6H11NH2-Py体系下合成出层状阴离子骨架磷酸铝［Al2P3O12H］2-·2［C6H11NH+3］(UT-4)的纯晶相, 采用一维27Al, 31P MAS NMR , 1H→31P CP(Cross Polarization)以及二维27Al- 31P HETCOR(Heteronuclear Correlation)高分辨固体核磁共振技术对其骨架结构进行了表征. 采用两种方法对 27Al信号进行了归属, 并通过分析27Al-31P HETCOR谱对31P 信号进行了归属.     

HZSM-5分子筛焙烧脱铝的27Al MQMAS NMR研究

用29Si、27Al魔角旋转固体核磁共振(MAS NMR)结合二维多量子魔角旋转(2D MQMAS)技术对焙烧脱铝的HZSM-5分子筛中铝的配位状态进行了研究.结果表明,HZSM-5分子筛经焙烧后,在化学位移(δ)45处出现一宽峰信号,其主要来自扭曲四配位铝.通过二维三量子铝谱计算出扭曲四配位铝的四极作用常数约为5.2 MHz.对700和750 ℃焙烧样品的铝谱进行分峰拟合,发现在δ 30处又出现一个小峰,归属为非骨架五配位铝.同时,在750 ℃焙烧样品的二维多量子铝谱中直接观察到非骨架五配位铝的信号.焙烧温度低于700 ℃,脱铝不明显；高于700 ℃,引起分子筛骨架的显著脱铝.焙烧还造成部分骨架铝的信号变得“不可观测”.     

用固体核磁共振研究Al/P>1的磷酸铝分子筛AlPO4-5

用固体高分辩核磁共振（ＮＭＲ）方法对一系列Ａｌ／Ｐ＞１的新型磷酸铝分子筛ＡｌＰＯ４－５中磷和铝的结构状态及联结方式进行了研究，＾２７Ａｌ和＾３１Ｐ ＮＭＲ都给出了在分子筛骨架中存在有Ａｌ－Ｏ－Ａｌ联结方式的实验证据，寓示着在该体系中Ｐ和Ａｌ的排布不再遵循Ｌｏｅｗｅｎｓｔｅｉｎ规则。     

AlON尖晶石微结构的固体NMR研究

γ-Al₂O₃为低温型晶体,是尖晶石型结构,n(O)∶n(Al³⁺)为1∶2,在氧化气氛下升温至950～1000℃时,则向α-Al₂O₃转变.α-Al₂O₃中氧原子呈六方密堆积,Al³⁺离子仅占据氧八面体空隙.     

Formation Mechanism and Emission Spectrum of AlO Radicals in Reaction of Laser－ablated Al Atom and Oxygen

IntroductionLaser ablation has been applied broadly toplasma production,cluster formation,nanometermaterial and thin film material preparation[1,2 ] .Us-ing spectroscopic technique and mass spectrometryto identify the transient species formed in the pro-cess could provide much useful information aboutthe prosperity ofplasma,the mechanism of materi-al growth[3 ,4] .Aluminum is an important metal material andwidely used in industry and daily life. To study thereaction mechanism of Al atoms with…     

B2O3/ZrO2催化剂的11B MAS NMR表征

 用11B MAS NMR技术研究了B2O3/ZrO2催化剂中B2O3活性组分的存在形式及作用状态. 结果表明,B2O3在ZrO2表面以三配位BO3与四配位BO4结构单元存在. ZrO2载体的预焙烧温度和硼含量对B2O3的作用状态具有重要的影响,并改变BO3与BO4结构单元之间的比例. 催化剂表面吸附水的存在对BO4与BO3之间的分布有很大的影响,催化剂焙烧脱水至少可使部分BO4转化为BO3. BO4结构形式容易在无定形的微孔大比表面积的ZrO2表面形成; BO3结构形式却倾向于在结晶形的中孔小比表面积的ZrO2上存在.     

Rare gas effects on hyperfine coupling constants of BO, AlO, and GaO

Using density functional theory methods and large basis sets, we calculated hyperfine coupling constants (HFCCs) for the (11)B, (17)O, (27)Al, and (69)Ga nuclei of the radicals BO, AlO, and GaO (XO), embedded in 2-14 rare gas (Rg) Ne and Ar atoms. Kr atoms were included for AlO. The distance of the Rg atoms from XO was varied from 4 to 12 bohr. Matrix effects cause A(iso)(X) to increase, accompanied by decreases in A(dip)(X) and A(dip)(O), while A(iso)(O) remains close to zero. Changes are largest for AlO, slightly smaller for GaO, and very small for BO, in line with the molecular polarizabilities. Observed changes of A(iso)(X) and A(dip)(X) for BO in Ne matrixes and for AlO in Ne, Ar, and Kr matrixes are reproduced in complexes with 12 Rg atoms at distances of 5-6 bohr or 14 Rg atoms at distances of 6-7 bohr. For GaO, experimental data are available only in Ne matrixes. Theoretical results obtained for HFCCs of (17)O could not be verified due to insufficient experimental information. Estimates of HFCCs in matrixes not yet experimentally studied and for GaO in the gas phase have been made. Due to the interaction with rare gas atoms, p-spin density on the X and O atoms of XO is converted into s-spin density on X, thereby causing an increase (in magnitude) of A(iso)(X), accompanied by decreases in A(dip) of X and O. The higher polarizability of XO along the bond axis is reflected in complexes that have axial Rg atoms showing larger changes in HFCCs than comparable complexes without axial Rg atoms.     

Towards guest-zeolite interactions: an NMR spectroscopic approach

Guest(metal)-zeolite interactions in a two component heterogeneous catalyst have been investigated by high-field and high-speed (27)Al MAS NMR, and two-dimensional (27)Al MQ MAS NMR experiments as well as ab initio DFT methods. It was established that strong interactions between guest and zeolite occur in a metal/zeolite system, with the metal anchored to the tetrahedral aluminum framework site through two oxygen bridges. It disturbs the tetrahedral environment of associated aluminum framework, changing AlO(4) geometry from near T(d) to C(2v); this enables us to resolve this species from the undisturbed aluminum framework species in high-field (27)Al MAS NMR and two-dimesional (27)Al MQ MAS NMR experiments.     

Aluminum orthovanadate (AlVO4): synthesis and characterization by (27)Al and 51V MAS and MQMAS NMR spectroscopy

Polycrystalline samples of AlVO(4) have been prepared by two methods of synthesis and characterized by (27)Al and (51)V MAS NMR spectroscopy at 14.1 T. The MAS NMR spectra clearly reveal that essentially pure samples with minor impurities of V(2)O(5) and alumina have been obtained. From these samples, (27)Al quadrupole coupling parameters and isotropic chemical shifts as well as the magnitudes and relative orientations of the (51)V quadrupole coupling and chemical shift tensors have been determined with high precision for AlVO(4). These data have been obtained from a combined analysis of multiple-quantum (MQ) MAS NMR spectra and MAS NMR spectra of the central and satellite transitions. The (27)Al and (51)V NMR data show that the asymmetric unit for AlVO(4) contains three isolated VO(4) tetrahedra, one pentacoordinated Al site, and two AlO(6) octahedra. This is in agreement with the supposition that AlVO(4) is isostructural with FeVO(4) and with a recent structure refinement for AlVO(4) based on powder X-ray diffraction (XRD) data. The favorable agreement between the refined crystal structure from powder XRD and the NMR parameters is apparent from a convincing correlation between experimental (51)V quadrupole tensor elements and calculated (51)V electric field gradient tensor elements obtained by the point-monopole approach. An assignment of the (27)Al NMR data is obtained from similar calculations of the (27)Al electric field gradients and by estimation of the distortion of the AlO(6) octahedra.     

CaAl2B2O7：Eu的振动光谱和发光特性

采用高温固相反应法,合成了ＣａＡｌ２Ｂ２Ｏ７：Ｅｕ磷光体。测定了ＣａＡｌ２Ｂ２Ｏ７：Ｅｕ的振动光谱,结果表明ＢＯ３的振动吸收位于１４００－１６００ｃｍ＾－１区域内,ＡｌＯ６的吸收位于５１９ｃｍ＾－１。     

Si-VPI-5分子筛的多核固体NMR研究

磷酸铝类分子筛是近年来继Y型和ZSM七分子筛之后的第三代合成分子筛材料，其骨架由A10。和P0。四面体均匀交替地组成问．由于带负电行的A10。和带正电荷的PO。四面体数目相等，整个骨架呈电中性，所以这类分子筛本身无离子交换能力和催化活性．当用硅或某些金属离子（如Mg、Fe、Co、Zn等）对磷酸铝分子筛进行同晶取代，就会在骨架上造成电行不平衡，从而使这类分子筛具有一定的离子交换能力和酸性【习．因而对硅或金属离子在磷酸错类分子筛中取代机理的研究一直是人们感兴趣的问题问．Vpl－5是最近才合成出来的具有18圆环一维孔结构的…     

Direct Observation of Various Al Sites in SAPO-34by ^27Al Multiquantum(MQ) Magic Angle Spinning (MAS)NMR

The elegant 2D multiquantum (MQ) MAS NMR has been applied to investigate the coordination of Al atoms in SAPO-34.The results show that the effects of the template and /or water on the coordination of Al atoms are significant,which lead to the formation of various Al species.Up to four kinds of Al species are distinctly resolved.     

Solid-state NMR spectroscopy of anionic framework aluminophosphates: a new method to determine the al/p ratio

A series of anionic framework aluminophosphates, with different Al/P ratios, have been investigated by various solid-state NMR techniques, including 27Al, 31P magic angle spinning (MAS), 27Al-->31P cross polarization (CP), 27Al{31P} rotational echo double resonance (REDOR), and 31P{27Al} transfer of population double resonance (TRAPDOR). Different Al coordinations (AlO4b, AlO5b, and AlO6b) and P coordinations (PO4b, PO3bOt, PO2bO2t, and PObO3t), where b represents bridging oxygens and t represents terminal oxygens, can be unambiguously determined based on the solid-state NMR spectroscopy. Furthermore, a new method to determine the Al/P ratio of open-framework aluminophosphates has been established, which is useful for the understanding of unknown aluminophosphate structures.     

^29Si（^27Al）MAS NMR考察镧离子在LaDAlY型沸石中的作用

用~(29)Si(~(27)Al)MAS NMR和辅加乙酰丙酮(acac)处理样品的静态~(27)Al NMR研究了镧离子对脱铝Y型沸石(DAIY)骨架硅、铝和非骨架铝(EFAL)的影响.结果表明,~(29)Si MAS谱的化学位移及其形状不仅取决于连接[SiO_4]四面体的[AlO]-四面体数目,而且还与引入镧离子的量有关.镧离子的引入导致~(27)Al MAS谱的明显宽化和不对称形变.另外,还讨论了镧离子对非骨架铝的影响.     

Solid-state 1H and 27Al NMR studies of amorphous aluminum hydroxides

Two kinds of amorphous aluminum hydroxides, a sample precipitated from admixing AlCl3 and NaOH aqueous solutions and the commercial product, were measured by 27Al and 1H solid-state NMR spectroscopy. Pentahedral and tetrahedral coordinations, as well as octahedral coordination of oxygen atoms for aluminum, are observed in 27Al magic angle spinning (MAS) spectra of both amorphous samples. In contrast, octahedral coordination is only observed in gibbsite, bayerite, and boehmite. According to 1H MAS-NMR spectra under conditions of high spinning rate (35 kHz) and high field (14.09 T), free waters and OH groups coupled with aluminum for amorphous samples are observed at approximately 5 and approximately 4.5 ppm, respectively, the latter peak being broader. This is consistent with the differential spectra between spin echo and transfer of populations in double resonance. We conclude that the subunits of AlO4, AlO5, and AlO6 in amorphous aluminum hydroxides are bound through hydrogen bonds with a wide distribution of bonding strength.