Microporous metal-organic framework constructed from heptanuclear zinc carboxylate secondary building units

A novel, three-dimensional, noninterpenetrating microporous metal-organic framework (MOF), [Zn7O2(pda)5(H2O)2]5 DMF4 EtOH 6 H2O (1) (H2PDA=p-phenylenediacrylic acid, DMF=N,N-dimethylformamide, EtOH=ethanol), was synthesized by constructing heptanuclear zinc carboxylate secondary building units (SBUs) and by using rigid and linear aromatic carboxylate ligands, PDA. The X-ray crystallographic data reveals that the seven zinc centers of 1 are held together with ten carboxylate groups of the PDA ligands and four water molecules to form a heptametallic SBU, Zn7O4(CO2)10, with dimensions of 9.8 x 9.8 x 13.8 A3. Furthermore, the heptametallic SBUs are interconnected by PDA acting as linkers, thereby generating an extended network with a three-dimensional, noninterpenetrating, intersecting large-channel system with spacing of about 17.3 A. As a microporous framework, polymer 1 shows adsorption behavior that is favorable towards H2O and CH3OH, and substantial H2 uptake. In terms of the heptanuclear zinc carboxylate SBUs, polymer 1 exhibits interesting photoelectronic properties, which would facilitate the exploration of new types of semiconducting materials, especially among MOFs containing multinuclear metal carboxylate SBUs.     

Construction of mixed carboxylate and pyrogallate building units for luminescent metal-organic frameworks

A metal-organic framework,Ce-FDM-50,was constructed by employing gallic acid featuring both carboxylate and pyrogallate as the coordinating sites and Ce(Ⅲ).The co-assembly of the carboxylates and pyrogallates with two metal ions have achieved a new type of paddle wheel secondary building unit.These building units were further joined by organic struts to obtain frameworks in sql topology.This synthetic approach could be expanded to five different lanthanide metals(Nd,Eu,Gd,Tb,Yb)for the construction of a series of isoreticular MOFs based on FDM-50,and even MTV-MOFs in which mixed lanthanide metals with specific ratios were distributed.In addition,featuring the lanthanide metals as the inorganic nodes in the network,Tb-FDM-50 showed distinct luminescence properties that could be furtherly tuned for variable applications.     

Design and synthesis of hierarchical materials from ordered zeolitic building units

The crystallization of colloidal silicalite-1 from clear solution is one of the best understood zeolite formation processes. Colloidal silicalite-1 formation involves a self-assembly process in which nanoslabs and nanotablets with a silicalite-1 type connectivity are formed at intermediate stages. During the assembly process, with strongly anisometric particles present, regions appear with orientational correlations, as evidenced with measurements of dynamic light scattering, viscosity, and rotation of polarized light. The presence of such regions rationalizes the unexpected differences between the crystallization kinetics under microgravity and on earth. The discovery of the locally oriented regions sheds new light on currently poorly understood hydrodynamic effects on the zeolite formation processes, such as the influence of stirring on the phases obtained and the subsequent kinetics. Addition of surfactants or polymers modifies the ordering of the zeolitic building units in the correlated regions, and new types of hierarchical materials named zeogrids and zeotiles can be obtained.     

Structures and properties of porous coordination polymers based on lanthanide carboxylate building units

A series of 3-D lanthanide porous coordination polymers, [Ln(6)(BDC)(9)(DMF)(6)(H(2)O)(3)·3DMF](n) [Ln = La, 1; Ce, 2; Nd, 3], [Ln(2)(BDC)(3)(DMF)(2)(H(2)O)(2)](n) [Ln = Y, 4; Dy, 5; Eu, 6], [Ln(2)(ADB)(3)(DMSO)(4)·6DMSO·8H(2)O](n) [Ln = Ce, 7; Sm, 8; Eu, 9; Gd, 10], {[Ce(3)(ADB)(3)(HADB)(3)]·30DMSO·29H(2)O}(n) (11), and [Ce(2)(ADB)(3)(H(2)O)(3)](n) (12) (H(2)BDC = benzene-1,4-dicarboxylic acid and H(2)ADB = 4,4'-azodibenzoic acid), have been synthesized and characterized. In 1-3, the adjacent Ln(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, [Ln(4)(CO(2))(12)](n), that constructed a 3-D framework with 4 × 7 ? rhombic channels. In 4-6, the dimeric Ln(III) ions are interlinked to yield scaffolds with 3-D interconnecting tunnels. Compounds 7-10 are all 3-D interpenetrating structures with the CaB6-type topology structure. Compound 11 is constructed by ADB spacers and trinulcear Ce nodes with a NaCl-type topology structure and a 1.9-nm open channel system. In 12, the adjacent Ce(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, [Ln(4)(CO(2))(12)](n), and give rise to a 3-D framework. Moreover, 6 exhibits characteristic red luminescence properties of Eu(III) complexes. The magnetic susceptibilities, over a temperature range of 1.8-300 K, of 3, 6, and 7 have also been investigated; the results show paramagnetic properties.     

The synthesis of complexes using precursor complexes with ferrocenyl carboxylate units as building blocks

Using ferrocenyl carboxylates as functional ligands, we synthesized a mononuclear complex [Zn(η²-OOCCHCHFc)₂(CH₃OH)₂] (1) and a binuclear complex [Cd(bafca)₂(H₂O)₂]₂ (2) (bafca⁻ = α-benzamido-β-ferrocenylacrylic carboxylate) as precursor complexes. Investigation on the substitution reaction of precursor complexes as building blocks in solution-state, four complexes [Zn(OOCCHCHFc)₂(bbbm)]_n (1a), {[Zn(OOCCHCHFc)(ntb)](CH₃OH)} (1b), [Cd(bafca)₂(2,2′-bpy)]₂ · 9H₂O (2a) and {[Cd(bafca)₂(bbbm)(CH₃OH)₂] · 6CH₃OH}_n (2b) were obtained (bbbm = 1,1-(1,4-Butanediyl)bis-1H-benzimidazole, ntb = N,N-bis(1H-benzimidazol-2-ylmethyl)-1H-Benzimidazole-2-methanamine and 2,2′-bpy = 2,2′-bipyridine). As anticipated, the structural integrity of precursor complexes can be maintained in these four complexes. It indicates that we can synthesize the desired complexes with the destination structures by using precursor complexes as building blocks and choosing appropriate auxiliary ligands. In addition, the electrochemical properties of all complexes were investigated, and it can be seen from the results that half-wave potentials of these complexes are slightly higher than that of the corresponding ligand.     

Tetrameric molecular bowl assembled from glycoluril building blocks

Glycoluril derivative--whose bulky Ph-C[triple bond]C- substituents prevent formation of H-bonded tapes--undergoes solvent dependent assembly in the crystal; a tetrameric molecular bowl is formed by R(24) H-bonding interactions from CH(2)Cl(2) whereas DMF results in H-bond dimerization followed by oligomerization via C-H...pi interactions.     

To improve the key properties of nonlinear optical crystals assembled with tetrahedral functional building units

Nonlinear optical (NLO) crystals assembled with conventional non-π-conjugated tetrahedral functional building units (FBUs), generally referring to [PO₄] and [BO₄], usually exhibit weak nonlinearity and poor birefringence. It is currently proposed that partially substituting oxygen atoms with fluoride atoms in these FBUs could enhance these crucial properties. Hence, we investigated for the first time the NLO-related properties of NH₄BAsO₄F (ABAF), which was constructed from tetrahedral [BO₃F] and [AsO₄] FBUs, and enhancements of these properties were observed in this material, that is large second-harmonic generation (SHG) response (2 × KDP) and improved birefringence (0.03 at 1064 nm). Notably, both SHG coefficient and birefringence of ABAF exceeded those of a great majority of phosphates, sulfates, or boron phosphates and achieved a preferable balance. It is interesting that ABAF shows vast structural similarities to the typical NLO crystals Sr₂Be₂B₂O₇ (SBBO) and KBe₂BO₃F₂ (KBBF), which might be the partial reason why it showed improvement in these vital properties. This work may afford some inspiration for enhancing the key performances of NLO crystals assembled with non-π-conjugated tetrahedra.

We report a new nonlinear optical crystal assembled exclusively with tetrahedral functional building units in which enhanced birefringence (Δn) and second-harmonic generation (d_eff) were observed.     

Exploring the self-assembly of dumbbell-shaped polyoxometalate hybrids,from molecular building units to nanostructured soft materials

The formation of hierarchical nanostructures using preformed dumbbell-like species made of covalent organic–inorganic polyoxometalate (POM)-based hybrids is herein described. In this system, the presence of charged subunits (POM, metal linkers, and counter ions) in the complex molecular architecture can drive their aggregation, which results from a competition between the solvation energy of the discrete species and intermolecular electrostatic interactions. We show that the nature of the POM and the charge of the metal linker are key parameters for the hierarchical nanoorganization. The experimental findings were corroborated with a computational investigation combining DFT and molecular dynamics simulation methods, which outlines the importance of solvation of the counter ion and POM/counter ion association in the aggregation process. The dumbbell-like species can also form gels, in the presence of a poorer solvent, displaying similar nanoorganization of the aggregates. We show that starting from the designed molecular building units whose internal charges can be controlled by redox trigger we can achieve their implementation into soft nanostructured materials through the control of their supramolecular organization.

The formation of hierarchical nanostructures using supramolecular dumbbell-like species made of organic–inorganic polyoxometalate-based hybrids is investigated by combination of SAXS and computational methods.     

Three-component reactions leading to 2D and 3D metal-organic frameworks assembled on dinickel-carboxylate secondary building units

Three-component reactions involving Ni(II) ions and dicarboxylate and bipyridyl ligands under hydrothermal conditions produce two novel metal-organic coordination polymers formulated empirically as [Ni(PDA)(BPE)] (1) and [Ni₂(PDA)₂(BPP)(H₂O)]·2.5H₂O (2), where PDA = 1,4-phenylenediacetate, BPE = 1,2-bis(4-pyridyl)ethane, and BPP = 1,3-bis(4-pyridyl)propane. Both compounds possess 2D or 3D metal-organic frameworks (MOFs) that are assembled on dinickel-carboxylate secondary building units. Compound 1 has a condensed 3D MOF, whereas 2 contains void between 2D MOFs where guest water molecules reside. Both compounds demonstrate antiferromagnetic coupling between Ni(II) ions.     

A luminescent linear trinuclear magnesium complex assembled from a phosphorus-based tris-hydrazone ligand

A novel linear trinuclear magnesium complex (P(S)[N(CH3)N=CHC6H4-o-O]3)2Mg3 was prepared by the reaction of P(S)[N(CH3))N=CHC6H4-o-OH]3 with MgCl2 x 6H2O in the presence of triethylamine. The trinuclear magnesium complex is fluorescent in solution as well as in the solid-state.     

Cluster assembled thin films of covalent materials

Cluster assembled thin films of covalent materials are studied by Raman spectroscopy. The main properties are discussed in terms of frustration through several examples (carbon, silicon, and boron nitride). Some applications such as luminescence are discussed.     

Rod packings and metal-organic frameworks constructed from rod-shaped secondary building units

The principal structure possibilities for packing infinite rod-shaped building blocks are described. Some basic nets derived from linking simple rods (helices and ladders) are then enumerated. We demonstrate the usefulness of the concept of rod secondary building units in the design and synthesis of metal-organic frameworks (MOFs). Accordingly, we present the preparation, characterization, and crystal structures of 14 new MOFs (named MOF-69A-C and MOF-70-80) of 12 different structure types, belonging to rod packing motifs, and show how their structures are related to basic nets. The MOFs reported herein are of polytopic carboxylates and contain one of Zn, Pb, Co, Cd, Mn, or Tb. The inclusion properties of the most open members are presented as evidence that MOF structures with rod building blocks can indeed be designed to have permanent porosity and rigid architectures.     

含硫芳香羧酸与三唑配体构筑的镍配合物的合成及结构

以1-氢-3,5-二(3-吡啶基)-1,2,4-三唑和2,2'-二硫二苯甲酸(H2L)为混合配体与硝酸镍反应合水热成了一个镍配合物[Ni(L)(3,3'-bpt)2·(H2O)3]·H2O(3,3'-bpt=3,5-二(3-吡啶基)-1,2,4-三唑,L=脱质子2,2'-二硫二苯甲酸)(1)并利用元素分析、红外和X射线单晶衍射法对其结构进行了表征。结果表明标题配合物属于单斜晶系,P21空间群,晶胞参数为a=7.9020(16),b=19.152(4),c=18.196(4),β=92.69(3)°,V=2750.7(10)3,Z=4,F(000)=1360,S=1.067。配合物中金属镍(Ⅱ)形成六配位畸变八面体构型,相邻的镍结构单元通过三唑配体的吡啶氮原子桥联形成一维无限链状结构,整个配合物通过丰富的氢键形成三维网络结构(CCDC:986971)。     

Natural radioactivity in Zambian building materials collected from Lusaka

Samples of natural and manufactures building materials collected around Lusaka have been analyzed for natural radionuclides using -spectrometry. A simple comparison of the specific radioactivities of primordial radionuclides in these materials to the world averages for soil (25 Bq kg^{–1 238}U, 25 Bg kg^{–1 232}Th, 370 Bq kg^{–1 40}K and 89 Bq kg^–1 Ra_eq) shows that, of the nine types of samples analyzed, only burnt clay bricks (for²³⁸U,²³²Th and⁴⁰K), cement roofing tiles (for²³⁸U), building and river sands (for²³²Th and⁴⁰K) have greater activities than does soil. Radiological evaluation of specific radioactivities in these materials indicates that all materials meet the external -ray dose limitation of 1.5 mSv y^–1, that is, all samples have a radium equivalent activity of less than 370 Bq kg^–1.     

Calorimetry of building materials

Classical adiabatic methods for measuring specific heat in a wide temperature range are very suitable for homogeneous, well defined materials. However, measurements on inhomogeneous materials require large samples, which makes using of adiabatic treatments extremely expensive. In this paper, a nonadiabatic method for determining the specific heat of inhomogeneous building materials within the wide temperature range of ?30 to 1200°C is presented. The method is relatively simple, very cheap, and sufficiently accurate for use with building materials. Tests of the new developed method on two typical building materials, concrete and basalt fibreboards, demonstrate the method's applicability to practical measurements.     

Mo/Rh carboxylate: heterometallic compound built of homometallic paddlewheel units

Mixed-metal molybdenum(II)/rhodium(II) tetra(trifluoroacetate) of the composition [(MoRh)(O2CCF3)4] has been obtained from the gas-phase reaction between volatile carboxylates, [Mo2(O2CCF3)4] and [Rh2(O2CCF3)4]. This is an interesting system for which a single-crystal X-ray investigation fails to provide an unambiguous evidence of whether the product consists of the initial homometallic or newly formed heterometallic paddlewheel units. In the solid-state structure both metal atoms occupy the same crystallographic position, while the M-M and M-O distances are averaged with respect to the parent homometallic compounds. Nevertheless, the results of mass-spectrometric and magnetic measurements clearly indicate that the title bimetallic carboxylate contains a statistical mixture of homometallic dimolybdenum and dirhodium units. The product can be considered as a result of cocrystallization of isomorphous paddlewheel molecules.     

Porous coordination polymers with zeolite topologies constructed from 4-connected building units

Two novel 3D coordination polymers, Cd(CTC)(H2O).(H2PIP)(0.5)(H2O) (1) with zeolite ABW topology and Cd(CTC).(HIPA) (2) with zeolite BCT topology, have been synthesized by constructing inorganic and organic 4-connected building units and using the organic bases as templates, and the frameworks of and not only expand the original structures of zeolites ABW and BCT, but also exhibit significant advantages over them in terms of thermal stability, ion exchange and adsorption.     

Phospholipids from some common fungi associated with damp building materials

Methods for the analysis of fungal biomass in contaminated building materials have been limited to methods that use viable propagules as well as indicators of total biomass such as fungal glucan and ergosterol. Because of large differences in the survival times of spores, and limitations imposed by the use of agar media to assess fungal cells for the former approach, no quantitative information and poor qualitative information is obtained. The use of the biochemical indicators provides reliable quantitative information but no qualitative data. Analysis of phospholipids of various bacteria and, recently, of fungi common in outdoor air has provided both qualitative and quantitative data on their distributions in various substrates including in outdoor air samples. In this report, we provide new data on the signature lipids of some fungi common on moldy building materials. Using the LC/MS/MS analysis described, an estimate can be made of the fresh weight of fungal cells and the relative abundance of the common genera of fungi typically found on moldy materials.     

Ligands derived from tetrathiafulvalene: building blocks for multifunctional materials

The last decade has witnessed many advances in the coordination chemistry of tetrathiafulvalene (TTF). Various ligands, in which a metal-binding functionality is attached to the TTF unit, have been synthesized and used for the preparation of metal complexes. This Perspective summarizes the main types of TTF-containing ligands and their metal complexes and outlines the potential for the use of these building blocks in the design and assembly of multifunctional molecular materials.     

Synthesis and catalytic properties of hybrid mesoporous materials assembled from polyhedral and bridged silsesquioxane monomers

A family of hybrid mesoporous materials with high temperature stability was obtained by the suitable covalent combination of two types of siloxane precursors. Specifically, cubic T(8) polyhedral oligomeric (POSS) and aryl bridged silsesquioxane monomers (1,4-bis(triethoxysilyl)benzene, BTEB) play the role of nanobuilders. An optimal molar ratio of the two precursors (5-25 mol% of total silicon content from the BTEB disilane) generated a homogenous, highly accessible, and well-defined mesoporous material with hexagonal symmetry and narrow pore-size distribution. Physicochemical, textural, and spectroscopic analysis corroborated the effective integration and preservation of the two different nanoprecursors, thereby confirming the framework of the mesoporous hybrid materials. A post-synthesis amination treatment allowed the effective incorporation of amino groups onto the aryl linkers, thereby obtaining a stable and recyclable basic catalyst for use in C-C bond-formation processes.