Zirconium Phosphite (3,3?,5,5?-Tetramethylbiphenyl)diphosphonate, a Microporous, Layered, Inorganic-Organic Polymer

Nanoporous Metal Phosphonate Hybrid Materials as a Novel Platform for Emerging Applications: A Critical Review

Nanoporous metal phosphonates are propelling the rapid development of emerging energy storage, catalysis, environmental intervention, and biology, the performances of which touch many fundamental aspects of portable electronics, convenient transportation, and sustainable energy conversion systems. Recent years have witnessed tremendous research breakthroughs in these fields in terms of the fascinating pore properties, the structural periodicity, and versatile skeletons of porous metal phosphonates. This review presents recent milestones of porous metal phosphonate research, from the diversified synthesis strategies for controllable pore structures, to several important applications including adsorption and separation, energy conversion and storage, heterogeneous catalysis, membrane engineering, and biomaterials. Highlights of porous structure design for metal phosphonates are described throughout the review and the current challenges and perspectives for future research in this field are discussed at the end. The aim is to provide some guidance for the rational preparation of porous metal phosphonate materials and promote further applications to meet the urgent demands in emerging applications.

Permanent porosity and role of sulfonate groups in coordination networks constructed from a new polyfunctional phosphonato-sulfonate linker molecule

The new linker molecule (H2O3PCH2)2N-CH2C6H4SO3H, (4-{[bis(phosphonomethyl)amino]methyl}benzene-sulfonic acid, H5L), bearing both phosphonic and sulfonic acid groups, was employed for the synthesis of new coordination polymers (CPs). Four new CPs of composition [Mg(H3L)(H2O)2]·H2O (1), [Mg2(HL)(H2O)6]·2H2O (2), [Ba(H3L)(H2O)]·H2O (3) and [Pb2(HL)]·H2O (4), were discovered using high-throughput methods and all structures were determined by single-crystal X-ray diffraction (SCXRD). With increasing ionic radius of the metal ion, an increase in coordination number from CN = 6 (Mg2+) to CN = 9 (Ba2+) and an increase in the dimensionality of the network from 1D to 3D is observed. This is reflected in the composition of the IBU and the number of metal ions that are connected by each linker molecule, i.e. from three in 1 to ten in 4. The connection of the IBUs leads to 1D and 2D structures in 1 and 2 with non-coordinating sulfonate groups, while 3 and 4 crystallise in MOF-type structures and coordination of the sulfonate groups is observed. The compounds exhibit thermal stabilities between 200 (2) and 345 °C (4) as proven by variable temperature powder X-ray diffraction (VT-PXRD) measurements. Title compound 4 contains micropores of 4 × 2 Å and reversible H2O uptake of 50 mg g-1 was demonstrated by vapour sorption measurements, making it the first porous metal phosphonatosulfonate. Detailed characterisation, i.e. CHNS and TG analysis as well as NMR and IR spectroscopy measurements confirm the phase purity of the title compounds.

Local Environment of Terbium(III) Ions in Layered Nanocrystalline Zirconium(IV) Phosphonate-Phosphate Ion Exchange Materials

The structures of Zr(IV) phosphonate-phosphate based, unconventional metal organic framework materials have been determined using atomic pair distribution function analysis of high energy, X-ray total scattering diffraction data. They are found to form as nanocrystalline layers of Zr phosphate, similar to the bulk, but with a high degree of interlayer disorder and intermediate intralayer order extending around 5 nm. These materials are of interest for their high selectivity for 3+ lanthanide ions. To investigate the mechanism of the selectivity, we utilize difference pair distribution function analysis to extract the local structural environment of Tb³⁺ ions loaded into the framework. The ions are found to sit between the layers in a manner resembling the local environment of Tb in Scheelite-type terbium phosphate. By mapping this local structure onto that of the refined structure for zirconium-phenyl-phosphonate, we show how dangling oxygens from the phosphate groups, acting like nose hairs, are able to reorient to provide a friendly intercalation environment for the Tb³⁺ ions.

Template-free synthesis of nanoporous gadolinium phosphonate as a magnetic resonance imaging (MRI) agent

Organic–inorganic hybrid porous gadolinium phosphonate materials are synthesized using benzene-1,3,5-triphosphonic acid as phosphonic acid linker.

High valence 3p and transition metal based MOFs

This article focuses on high valence 3p and transition metal based metal organic frameworks.

The use of a rigid tritopic phosphonic ligand for the synthesis of a robust honeycomb-like layered zirconium phosphonate framework

1,3,5-Tris(4-phosphonophenyl)benzene was synthesized via a microwave heating assisted route and was subsequently used for the preparation of a new zirconium phosphonate with honeycomb-like structure displaying remarkable thermal stability and hydrolysis resistance.

The first route to highly stable crystalline microporous zirconium phosphonate metal–organic frameworks

The first crystalline microporous zirconium phosphonate metal–organic framework (UPG-1) was synthesized using the novel tritopic ligand 2,4,6-tris(4-(phosphonomethyl)phenyl)-1,3,5-triazine.

A Review on the Synthesis and Applications of Mesostructured Transition Metal Phosphates

Considerable efforts have been devoted to extending the range of the elemental composition of mesoporous materials since the pioneering work of the M41S family of ordered mesoporous silica by Mobil researchers. The synthesis of transition metal-containing mesostructured materials with large surface area and high porosity has drawn great attention for its potential applications in acid and redox catalysis, photocatalysis, proton conducting devices, environmental restoration and so on. Thus, various transition metals-containing mesoporous materials, including transition metal-substituted mesoporous silicates, mesostructured transition metal oxides and transition metal phosphates (TMP), have been documented in the literature. Among these, mesostructured TMP materials are less studied, but possess some unique features, partly because of the easy and facile functionalization of PO₄ and/or P-OH groups, rendering them interesting functional materials. This review first introduced the general synthesis strategies for manufacturing mesostructured TMP materials, as well as advantages and disadvantages of the respective method; then, we surveyed the ongoing developments of fabrication and application of the TMP materials in three groups on the basis of their components and application fields. Future perspectives on existing problems related to the present synthesis routes and further modifying of the functional groups for the purpose of tailoring special physical-chemical properties to meet wide application requirements were also provided in the last part.

Direct Synthesis of Functional Zeolitic Materials

Recently, the direct synthesis of zeolitic materials has received much attention because several well-defined functionalities have been introduced in those materials by “one-pot” methodologies. The rationalization of the physics and chemistry of the processes involved in the zeolite growth has allowed the direct preparation of different functional molecular sieves with unique properties and potential applicability in industry. In the present paper, the “one-pot” preparations of metal-containing zeolites (both in framework and extra-framework positions), hybrid organic-inorganic molecular sieves, hierarchical microporous mesoporous zeotypes, nanosheets, nanozeolites, or template-free molecular sieves are intensively evaluated.

Layered metal phosphonate reinforced poly(L-lactide) composites with a highly enhanced crystallization rate

Layered metal phosphonate, zinc phenylphosphonate (PPZn), reinforced poly(L-lactide) (PLLA) composites were fabricated by a melt-mixing technique. The nonisothermal and isothermal crystallization, melting behavior, spherulite morphology, crystalline structure, and static and dynamic mechanical properties of the PLLA/PPZn composites were investigated. PPZn shows excellent nucleating effects on PLLA crystallization. With incorporation of 0.02% PPZn, PLLA can finish crystallization under cooling at 10 degrees C/min. The crystallization rate of PLLA further increases with increasing PPZn concentration. Upon the addition of 15% PPZn, the crystallization half-times of a PLLA/PPZn composite decrease from 28.0 to 0.33 min at 130 degrees C, and from 60.2 to 1.4 min at 140 degrees C, compared to the neat PLLA. With the presence of PPZn, the nuclei number of PLLA increases and the spherulite size reduces significantly. Through analysis of the crystal structures of PLLA and PPZn, it was proposed that the nucleation mechanism of the PLLA/PPZn system is epitaxial nucleation. The incorporation of PPZn has no discernible effect on the crystalline structure of PLLA. Moreover, PPZn has good reinforcement effects on the PLLA matrix. The tensile strength of the composite is enhanced with the addition of a relatively small amount of PPZn (<5%). The tensile and storage moduli of composites increase with increasing PPZn loadings, and they respectively improve by 28% and 34% with the incorporation of a 15% PPZn filler, as compared to the neat PLLA.

Rare Earth Arenedisulfonate Metal−Organic Frameworks: An Approach toward Polyhedral Diversity and Variety of Functional Compounds

Eight 2D and 3D metal-organic framework (MOF) rare earth naphthalenedisulfonates have been obtained. The different geometry of the naphthalenedisulfonic acids used as connectors [(1,5-NDS) and (2,6-NDS)] gives rise to the three new structure types. In Ln(OH)(1,5-NDS)H2O, LnPF-1 (lanthanide polymeric framework; Ln=La, Nd, Pr, Sm and Eu), the lanthanide ion is octacoordinated. Its 3D structure is formed by (Ln2O14)-S-(Ln2O14) infinite chains, connected through complete NDS connectors. LnPF-2 (Ln=Nd), with the same empirical formula as the former, and the lanthanide in octa- and nonacoordination, owns an arrangement of sulfonate bridges and neodymium polyhedra that gives rise to a 2D structure. [Ln5(2,6-NDS)3(OH)9(H2O)4](H2O)2, LnPF-3 (Ln=Nd, Eu), demonstrates that it is possible to obtain a 3D structure with (2,6-NDS), when a greater Ln/connector ratio is employed. It is worth pointing out the existence, in this latter family of compounds, of a mu5-OH group, whose hydrogen atom is very close to one-sixth Ln atom (distance Ln...H=2.09 A). The materials, with high thermal stability, act as active and selective bifunctional heterogeneous catalysts in oxidation of linalool yielding cyclic hydroxy ethers. The absence of any 3D Nd-Nd magnetic interaction is explained due to the inner nature of 4f orbitals of Nd3+, which do not favor the magnetic exchange. The influence of the polymeric frame matrix results in a better photoluminescence efficiency for NdPF-1.

Nanosized Gradient π-Conjugated Thienylethynylene Dendrimers for Light Harvesting: Synthesis and Properties

[reaction: see text] A family of pi-conjugated dendrimers based on truxene and thienylethynylene units are synthesized via a mixed divergent/convergent growth approach. These dendrimers possess an intrinsic energy gradient from the periphery to the core through branches and thus show a broad absorption in the UV-vis range and an efficient energy transfer to the lower-energy center. The molecules hence have the potential to be used as light harvesting materials.

Titanium Phosphonate Porous Materials Constructed from Dendritic Tetraphosphonates

An organic-inorganic hybrid material, TPPhA-Ti, was constructed by non-hydrolytic condensation of a dendritic tetrakis-1,3,5,7-(4-phosphonatophenyl)adamantane precursor and titanium(IV) isopropoxide. One preparative pathway yielded insoluble materials with a Ti/P ratio of approximately 1 which was confirmed by a combination of FT-IR, TGA, and EDS measurements. N2 sorption experiments showed that TPPhA-Ti is a porous solid (micropores approximately 13 A; mesopores approximately 38 A) with a high surface area, approximately 550 m2 g(-1). The structure and morphology of the TPPhA-Ti as investigated by transmission and scanning electron microscopy showed a layered-type material. Additional X-ray diffraction data suggest a paracrystalline material; an optimization of possible molecular arrangements of TPPhA-Ti was simulated that was in agreement with the experimental data. A second preparative pathway yielded a Ti oxide-phosphonate with a Ti/P ratio of approximately 3.4. Both TEM and SEM revealed that hollow nanospheres were formed with diameters of approximately 180-300 nm.

Structural Constraints in the Design of Silver Sulfonate Coordination Networks: Three New Polysulfonate Open Frameworks

Three new silver sulfonate metal-organic frameworks are presented along with a design strategy for future generations. [[Ag6(mesitylenetrisulfonate)2(H2O)5].2H2O]infinity (1), [Ag4(durenetetrasulfonate)(H2O)2](infinity) (2), and [[Ag4(1,3,5,7-tetrakis(4,4'-sulfophenyl)adamantane)(H2O)2].1.3H2O]infinity (3) represent a series of open-framework silver sulfonate solids where the organic linker plays a key role in determining the overall structure. Compound 1 forms a pillared layered structure, while compounds 2 and 3 form 3-D nets derived from cross-linking of 1-D columns of silver sulfonates. All three solids incorporate water molecules, which can be removed to yield a solid stable to in excess of 300 degrees C. Powder X-ray diffraction studies and vapor sorption experiments show, for 1 and 2, that the solids retain their structure when guests are removed and, for all three, that water vapor is resorbed stoichiometrically by the solids. An idealized silver sulfonate framework is proposed, and upon comparison to the reported structures, guidelines are proposed for structural constraints in the design of future generations of 1-D and possibly 0-D aggregate structures.

Vibrational Study of Some Layered Structures Based on Titanium and Zirconium Phosphates

A Raman and infrared study was carried out on layered zirconium and titanium acid phosphates of alpha- and gamma-type, alpha-M[O(3)POH](2).H(2)O and gamma-M[PO(4)][O(2)P(OH)(2)].2H(2)O, respectively. The spectra were initially approached by means of the classical correlation method in the solid state, which accounts for the complexity of the infrared spectra of both species. However, the number of bands and their relative intensity in the Raman spectra suggest a quite total absence of quadrupolar coupling between the vibrating units. So, if interunit coupling is neglected, a molecular approach considering the vibrations of isolated tetrahedral [PO(4)] and octahedral [MO(6)] building blocks can allow an affordable spectroscopic description of the title compounds. Interesting insights on the relationships between spectral properties and structure can be drawn by comparison with the spectra of alkali phosphates and of MO(6) oxoanions. A significant high-energy shift of the nu(P-O) modes is observed in the layered phosphates with respect to the corresponding salts, which parallels the low-energy shift of the nu(M-O) modes. Surprisingly, an increase of the M-OP interaction can reinforce the P-O bond. A simple theoretical model, based on the interaction between the [PO(4)] unit and four Li(+) in similar geometrical arrangement found in the structures of the layered phosphates, offers a reasonable explanation of this phenomenon.

Synthesis and Characterization of a New Bisphosphonic Acid and Several Metal Hybrids Derivatives

Commercial bis-(4-bromophenyl)-ether, [BrC(6)H(4)](2)-O, has been used to prepare 4-[4'-(diethoxyphosphoryl)phenoxy]phenyl-phosphonic acid diethyl ester, [(CH(3)CH(2))(2)O(3)P-C(6)H(4)](2)-O, (I) following a slight modification of the Michaelis-Arbuzov reaction. The acid hydrolysis of I gave 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H(2)O(3)P-C(6)H(4)](2)-O (II), and both compounds have been characterized by (1)H NMR and (13)C NMR. The crystal structure of II has been determined by single-crystal X-ray diffraction. II crystallizes in an orthorhombic unit cell, space group Pbcn, with a = 7.822(3) A, b = 5.821(2) A, c = 28.982(9) A, and V = 1319.7(7) A(3). The final R factor was R1 = 0.0614. The structure is layered, being held together through a hydrogen bonding network. II has been used as precursor in the syntheses of new metal (Mn, Fe, Co, Ni, Cu, and Zn) bisphosphonates. The syntheses were carried out using a fixed metal/bisphosphonic acid molar ratio of 2.1:1 and the influence of the pH in the reactions has been studied. Nine new compounds have been isolated: Mn(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).1.5H(2)O (III), Mn(5)(OH)(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3))(2).2H(2)O (IV), Fe(HO(3)PC(6)H(4)OC(6)H(4)PO(3)).0.5H(2)O (V), Co(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).2H(2)O (VI), Ni(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).3H(2)O (VII), Ni(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)).2H(2)O (VIII), Cu(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)) (IX), Zn(2)(O(3)PC(6)H(4)OC(6)H(4)PO(3)) (X), and Zn(HO(3)PC(6)H(4)OC(6)H(4)PO(3)H) (XI). Compound IX crystallizes in an orthorhombic unit cell, space group Pbcn, and unit cell parameters a = 8.1012(5) A, b = 5.3109(3) A, c = 29.2595(5) A, and V = 1258.8(1) A(3). Its structure has been solved by ab initio powder diffraction and refined by the Rietveld method to R(F) = 0.042. IX has a pillared layer framework with highly distorted CuO(5) groups sharing edges to give isolated dimers. XI was indexed in a monoclinic unit cell, space group P112(1), with parameters a = 9.4991(9) A, b = 5.0445(5) A, c = 29.131(2) A, gamma = 91.945(7) degrees, and V = 1395.1(3) A(3). Its structure has been refined by the Rietveld method, R(F) = 0.054, since it is isostructural with the known compound, Zn[HO(3)P(C(6)H(4))(2)PO(3)H]. All solids were also characterized by thermal analysis and IR and UV-Vis spectroscopies.