2.1.2. Low Topology/Framework Density 1003 2.1.3. Side Group Directed Superstructures 1003 2.2. Synthesis Considerations 1003 2.3. Special Properties 1004 3. Metal Imidazolate Frameworks 1004 3.1. Chains and Rings 1004 3.2. Zeolitic and Zeolite-like Frameworks 1006 3.2.1. SOD-Type Zinc(II) 2-Methylimidazolate 1007 3.3. Nonporous 4-Connected Networks 1010 3.4. Polyimidazolates 1011 4. Metal Pyrazolate Frameworks 1011 4.1. Clusters and Chains 1011 4.2. 3D Networks Based on Polypyrazolates 1012 5. Metal 1,2,4-Triazolate Frameworks 1014 5.1. Simple 3-Connected Networks 1015 5.2. Quasi-Imidazolates 1018 5.3. With Coordinative Substituents 1019 5.4. With Secondary Counterions and/or Ligands 1021 6. Metal 1,2,3-Triazolate Frameworks 1023 7. Metal Tetrazolate Frameworks 1025 7.1. Univalent Coinage-Metal Tetrazolate Frameworks 1025

Metal Azolate Frameworks: From Crystal Engineering to Functional Materials

1. Scope of Article and Previous Related Reviews 5346 2. Introduction 5346 2.1. Destruction 5347 2.2. Sensing 5347 2.3. Historical Context 5348 2.3.1. Brief History and Molecular Structure 5348 2.4. Related Compounds and Nomenclature 5348 2.4.1. Phosphorus(V) Parent Compounds and Fundamental Chemistry 5348 2.4.2. Pesticides 5349 2.4.3. Simulants 5349 2.4.4. Decomposition Products 5350 2.5. Toxicology 5351 2.5.1. Acetylcholine Esterase (AChE) Inhibition 5351 2.5.2. Endocannabinoid System Activation 5352 2.6. Critical Needs To Decontaminate and Detect 5353 2.7. Treaties and Conventions 5354 3. Stockpile Destruction 5355 3.1. Agent Storage 5355 3.2. Protection Protocols and Logistics 5355 3.3. Background 5355 3.4. Methods Currently Employed 5355 3.4.1. Incineration 5355 3.4.2. Neutralization by Base Hydrolysis 5356 4. Decomposition Reactions 5357 4.1. Hydrolysis 5357 4.2. Autocatalytic Hydrolysis or Hydrolysis Byproducts 5358 4.3. Use of Peroxide 5359 4.4. Oxidation with Bleach and Related Reagents 5360 4.5. Alkoxide as Nucleophile 5360 4.5.1. Basic Media 5360 4.5.2. Metal-Catalyzed Reactions 5361 4.5.3. Metal-Assisted Reactions 5363 4.5.4. Biotechnological Degradation 5363 4.5.5. Cyclodextrin-Assisted Reactions 5370 4.6. Halogen as the Nucleophile 5370 4.6.1. Use of BrOx 5370 4.6.2. Use of Other Halogens 5371 4.6.3. Use of Group 13 Chelates 5371 4.7. Surface Chemistry 5371 4.7.1. Bare Metals and Solid Nanoparticles 5371 4.7.2. Metal Oxides 5371 4.7.3. Representative Elements 5372 4.7.4. d-Block (Groups 4 10) 5373 4.7.5. Solid Metal Oxides of Group 3 and the Lanthanides 5375 4.7.6. Porous Silicon and Related Systems 5375 4.7.7. Zeolites 5375 4.7.8. Comparative IR Data 5375 4.8. Other Types of Systems 5375 5. Decontamination 5376 5.1. Overview: Ability to React with All Types of Agents, Ease of Application, and Compatibility with Treated Objects 5376 6. Agent Fate and Disposal 5378 6.1. Indoor 5378 6.2. Concrete and Construction Surfaces 5378 6.3. Landfills 5379 7. Sensing and Detection 5379 7.1. Possible Metal Ion Binding Modes in Solution 5379 7.1.1. Early Reports of Phosph(on)ate [R3PdO 3 3 3M nþ] Interactions (R= Alkyl, Alkoxyl) 5380 7.1.2. Coordination Chemistry of Downstream Non-P-Containing Products of Decomposition 5380 7.2. Colorimetric Detection 5381 7.3. Chemiluminescence: Fluorescence and Phosphorescence 5382 7.3.1. Lanthanide-Based Catalysts 5382 7.3.2. Organometallic-Based Sensors 5382 7.3.3. Organic Design 5382 7.3.4. Biologically-Based Luminescence Detection 5382 7.3.5. Polymer and Bead Supports 5382 7.4. Porous Silicon 5383 7.5. Carbon Nanotubes 5383

Destruction and Detection of Chemical Warfare Agents

Hydrophilic functionalization of nanoparticle surface is essential for their biomedical applications. Herein, we report a facile one-step reverse precipitation method to synthesize water-dispersible, biocompatible, and carboxylate-functionalized superparamagnetic magnetite (Fe3O4) nanoparticles with the help of biocompatible sodium citrate salt. Transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), zeta potential measurement, dynamic light scattering (DLS), and superconducting quantum interference device (SQUID) were used to characterize the as-prepared magnetite nanoparticles. The size of the as-prepared magnetite nanoparticles was tuned from 27 ± 3.8 to 4.8 ± 1.9 nm by changing the sodium citrate concentration from 25 to 125 mM. The sodium citrate concentration also influenced the water-dispersible stability of the as-prepared magnetite nanoparticles, which was due to the electrostatic repulsion.

One-step reverse precipitation synthesis of water-dispersible superparamagnetic magnetite nanoparticles

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

Yoon Jeong Jang,† Kibong Kim,† Olga G. Tsay,† David A. Atwood,‡ and David G. Churchill*,†,§ †Molecular Logic Gate Laboratory, Department of Chemistry, KAIST, Daejeon, 305-701, Republic of Korea ‡Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, United States Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), 373-1 Guseong-dong, Yuseong-gu, Daejeon, 305−701, Republic of Korea

Update 1 of: Destruction and detection of chemical warfare agents

We report a simple one-pot strategy to prepare surface-function-alized, water-dispersible iron oxide nanoparticles. Small organic molecules that have desired functional groups such as amines, carboxylics, and thiols are chosen as capping agents and are injected into the reaction medium at the end of the synthesis. A diversity of functionalities are effectively introduced onto the surface of the nanoparticles with a minimal consumption of solvents and chemical resources by simply switching the capping ligand to form the ligand shell. The resulting nanocrystals are quasi-spherical and narrowly size-distributed. Energy-dispersive X-ray analysis and Fourier transform infrared spectroscopy studies suggest a successful surface modification of iron oxide nanoparticles with selected functionalities. The colloidal stabilities are characterized by dynamic light scattering and zeta potential measurements. The results imply that functionalized nanoparticles are very stable and mostly present as individual units in buffer solutions. The pedant functional groups of the capping ligand molecules are very reactive, and their availabilities are investigated by covalently linking fluorescent dyes to the nanoparticles through the cross-linking of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The quenched quantum yield and shortened lifetime of the dyes strongly indicate a direct bonding between the functional group of the nanoparticles and the fluorescent molecules.

Water-Dispersible Iron Oxide Magnetic Nanoparticles with Versatile Surface Functionalities

The products of the reactions of copper(II) starting materials with 4-pyridyltetrazole (4-Hpt) in N,N-dimethylformamide (DMF)/methanol solutions are determined by the anion identity and concentration. In the absence of chloride, the 3-D open-framework material [Cu3(OH)3(4-pt)3(DMF)4]·5DMF·3MeOH (1·5DMF·3MeOH) is isolated, while variations in the chloride concentration yield the 2-D and 3-D materials, 2 and 3, respectively. All three structures exhibit trinuclear copper(II) building blocks: the triangular {Cu3(μ3-OH)}5+ core in 1 and {Cu3Cl4(4-pt)4(4-Hpt)2}2− and {Cu3Cl2(4-pt)8}4− chains in 2 and 3, respectively. All three materials display microporosity, which is highly dependent on the method of sample preparation.

Solid-state coordination chemistry of copper(II) tetrazolates: anion control of frameworks constructed from trinuclear copper(II) building blocks.

A series of organic-inorganic hybrid materials of the copper(II)-molybdophosphonate family have been prepared using conventional hydrothermal conditions. The reactions of MoO(3), copper(II) acetate, bipyrimidine (bpyr), a phosphonic acid, and water at temperatures below 160 degrees C and in the presence of a mineralizer such as acetic acid or HF provided crystalline samples of materials of the general class {Cu(2)(bpyr)}(4+)/Mo(x)O(y)-phosphonate. The recurrent themes of the structures are the presence of the binuclear {Cu(2)(bpyr)}(4+) and pentanuclear {Mo(5)O(15)(O(3)PR)(2)}(4-) building blocks. For the alkylphosphonate-containing materials, [{Cu(2)(bpyr)(2)}Mo(5)O(15)(O(3)PCH(3))(2)].2.5H(2)O (1.2.5H(2)O) is two-dimensional and exhibits {Cu(bpyr)}(n)(2n+) chains, while [{Cu(2)(bpyr)(H(2)O)}Mo(5)O(15)(O(3)PCH(2)CH(3))(2)] (2) is three-dimensional. The diphosphonate series of materials {{Cu(2)(bpyr)}(4+)[Mo(5)O(15){O(3)P(CH(2))(n)PO(3)}](4-) with n = 2-6 (4, 5, 7-9) in all cases contain the characteristic [Mo(5)O(15){O(3)P(CH(2))(n)PO(3)}](n)(2n+) chains, linked through {Cu(2)(bpyr)}(4+) rods into three-dimensional frameworks. When n = 1, the three-dimensional phase [{Cu(2)(bpyr)}MoO(2)(HO(3)PCH(2)PO(3))(2)].2H(2)O (3.2H(2)O) is obtained, the exclusive example of a structure constructed from isolated {MoO(6)} polyhedra rather than pentamolybdate clusters. The Ni(II)-containing phase [{Ni(2)(bpyr)(H(2)O)(4)}Mo(5)O(15){O(3)P(CH(2))(3)PO(3)}].9H(2)O (6.9H(2)O) was also prepared and compared to the structure of the Cu(II) analogue, [{Cu(2)(bpyr)(H(2)O)(4)}Mo(5)O(15){O(3)P(CH(2))(3)PO(3)}].3H(2)O (5.3H(2)O). Magnetic susceptibility studies of the compounds revealed that the magnetic behavior was consistent in all cases with antiferromagnetically coupled dimers. However, the magnitude of the exchange coupling was clearly dependent on the orientation of the M(II) mean equatorial or basal planes relative to the bipyrimidine plane. Thus, when the metal and bipyrimidine planes are nearly coplanar, the J values are in the -77 to -87 cm(-1) range, while J values of -2 to -5 cm(-1) are observed for the compounds with out-of-plane orientations.

Construction of Metal-Organic Oxides from Molybdophosphonate Clusters and Copper-Bipyrimidine Building Blocks

A study of BaTiO3 nanoparticles doped with different transition metals including Co, Fe, and Cr is presented. X-ray diffraction and electron microscopy studies indicated that all the samples are highly crystalline and that transition metal dopants are successfully incorporated into BaTiO3 without detectable secondary phases. Raman spectra featured three characteristic broad bands centered approximately 300, 520, and 715 cm−1 from the tetragonal BaTiO3 without any extra peak present that may be attributed to other impurity phases. Temperature- and field-dependent magnetometry measurements and analysis revealed that all the samples show paramagnetic-like behavior originating from the transition metal ions. These results not only allow the exclusion of potential secondary ferromagnetic or antiferromagnetic phases, but also suggest that transition metal ions (Co, Cr, and Fe) in BaTiO3 shown in this study are present as isolated paramagnetic centers.

Intrinsic magnetism in BaTiO3 with magnetic transition element dopants (Co, Cr, Fe) synthesized by sol-precipitation method

The hydrothermal chemistry of the copper-organonitrogen ligand/vanadium oxide/aromatic phosphonate system has been studied. Not only was HF required to induce crystallization, but product composition was highly dependent on the HF/V ratio of the reactions. At relatively low concentrations of HF/V of 6:1, materials of the Cu(II)-ligand/VxOy/organophosphonate type were observed, namely, [{Cu(phen)}2V2O5(O3PC6H4PO3)] (1), [Cu(phen)VO2(HO3PC6H4PO3)] (2), [{Cu(terpy)}2V2O5(O3PC6H4PO3)] (3), [{Cu(phen)(H2O)}VO2(HO3PC6H4PO3)] (6), [{Cu(phen)}VO2(HO3PC6H4PO3)] (7a and 7b), [Cu(C5H4NCO2)2V2O4(HO3PC6H4POH3)] (8), [Cu(bpy)VO2 {(HO3P)3C6H3}]·1.5H2O (12·1.5H2O), [{Cu(bpy)}2V3O7{(O3P)2C6H3PO3H}] (13) and [Cu(phen)V3O6(H2O){(O3P)2C6H3(PO3H)}] (14). When the HF concentration was raised, materials incorporating fluoride anion were observed; that is, compounds of the Cu(II)-ligand/VxOyFz/organophosphonate type: [{Cu(bpa)}2VO2F(H2O)(O3PC6H4PO3)]·H2O (4), [{Cu(bpa)}2V2O4F2(O3PC6H4PO3)] (5), [{Cu(bpy)}2V2O4F2(O3PC6H4PO3)] (9), [{Cu(terpy)}2V3O6F(HO3PC6H4PO3)2] (10), [{Cu(bpa)}2V2O4F2(O3PC6H4PO3)] (11). At HF/V concentrations of 25:1 or greater, vanadium free products, Cu(II) ligand/organophosphonate, were obtained: [Cu(C5H4NCO2)2(H2O3PC6H4PO3H2)]·H2O (15·H2O), [Cu(C5H4NCO2)2(H2O3PC6H4PO3H2)] (16), [Cu(bpy)(H2O){(HO3P)2C6H3(PO3H2)}] (17), [Cu(bpy){(HO3P)2C6H3(PO3H2)}]·H2O (18·H2O), [Cu(phen){(H2O3P)C6H3(PO3H)2}]·2H2O (19·2H2O) and [Cu(bpa){H2O3PC6H3(PO3H)2}]·H2O (20·H2O). The structural chemistry is unusually diverse with the Cu(II) ligand/VxOy/organophosphonate series exhibiting one-, two- and three-dimensional structures with a variety of copper-vanadate and vanadophosphonate substructures. The structural chemistry is discussed in relation to other examples of materials of the Cu(II) ligand/VxOy/organophosphonate and Cu(II) ligand/VxOyFz/organophosphonate families.

Hydrothermal chemistry of vanadium oxides with aromatic di- and tri-phosphonates in the presence of secondary metal copper(II) cationic complex subunits

Hongxue Liu

Papers

Water-Dispersible Iron Oxide Magnetic Nanoparticles with Versatile Surface Functionalities

Solid-state coordination chemistry of copper(II) tetrazolates: anion control of frameworks constructed from trinuclear copper(II) building blocks.

Construction of Metal-Organic Oxides from Molybdophosphonate Clusters and Copper-Bipyrimidine Building Blocks

Intrinsic magnetism in BaTiO3 with magnetic transition element dopants (Co, Cr, Fe) synthesized by sol-precipitation method

Hydrothermal chemistry of vanadium oxides with aromatic di- and tri-phosphonates in the presence of secondary metal copper(II) cationic complex subunits