Yan Xu

Bio: Yan Xu is an academic researcher from Liaoning Normal University. The author has contributed to research in topics: Crystal structure & Hydrothermal synthesis. The author has an hindex of 8, co-authored 19 publications receiving 152 citations.

Redetermination of iron(III) arsenate dihydrate

Abstract: Fe(AsO4)·2H2O was obtained hydro­thermally from an aqueous solution of iron(III) chloride, ethyl­enediamine and arsenic acid. The structure features six-coordinate iron with sulfate anions acting as bridging ligands.

Solvothermal Synthesis, Crystal Structure and Properties of a New Organic Templated Lanthanum Sulfate [C4N3H16][La(SO4)3(H2O)]

Abstract: A new organic templated lanthanum sulfate [C4N3H16][La(SO4)3(H2O)] (1) has been solvothermally synthesized by using n-butanol as solvent. The colorless block crystals were characterized by IR, TGA, ICP, and XRD. The structure was determined by single-crystal X-ray diffraction: Monoclinic, P21/c, a = 10.8878(19), b = 15.478(3), c = 9.9639(18) A, β = 114.062(2)°, V=1533.2(5) A3, Z = 4]. Crystal structure analysis shows that the one dimensional chain of 1 consists of the LaO9 polyhedra and the sulfate groups. Coordination water molecules link adjacent chains by using hydrogen bonds to generate 2D layers, whereas the organic amines are inserted between the layers. The formation of 1 demonstrates that solvents play an important role during the synthesis.

Luminescent Metal–Organic Frameworks

Abstract: Metal–organic frameworks (MOFs) display a wide range of luminescent behaviors resulting from the multifaceted nature of their structure. In this critical review we discuss the origins of MOF luminosity, which include the linker, the coordinated metal ions, antenna effects, excimer and exciplex formation, and guest molecules. The literature describing these effects is comprehensively surveyed, including a categorization of each report according to the type of luminescence observed. Finally, we discuss potential applications of luminescent MOFs. This review will be of interest to researchers and synthetic chemists attempting to design luminescent MOFs, and those engaged in the extension of MOFs to applications such as chemical, biological, and radiation detection, medical imaging, and electro-optical devices (141 references).

Underlying nets in three-periodic coordination polymers: topology, taxonomy and prediction from a computer-aided analysis of the Cambridge Structural Database

Abstract: We discuss a recently developed approach to formalize the analysis of extended architectures by successive simplifications of a crystal structure perceived as a periodic net. The approach has been implemented into the program package TOPOS that allows one to simplify and classify coordination polymers of any complexity in an automated mode. Using TOPOS, we retrieved 6620 3-periodic coordination polymers from the Cambridge Structural Database and represented them in a standard way as underlying nets. The topological classification of both 975 interpenetrating and 5645 single 3-periodic underlying nets has been performed and compared. The up-to-date methods for prediction of the topology of underlying nets are discussed and the ways to develop reticular chemistry are outlined.

Surface Interactions and Quantum Kinetic Molecular Sieving for H2 and D2 Adsorption on a Mixed Metal−Organic Framework Material

Abstract: A rational strategy has been used to immobilize open metal sites in ultramicroporosity for stronger binding of multiple H2 molecules per unsaturated metal site for H2 storage applications. The synthesis and structure of a mixed zinc/copper metal−organic framework material Zn3(BDC)3[Cu(Pyen)] ·(DMF)5(H2O)5 (H2BDC = 1,4 benzenedicarboxylic acid and PyenH2 = 5-methyl-4-oxo-1,4-dihydro-pyridine-3-carbaldehyde) is reported. Desolvation provides a bimodal porous structure Zn3(BDC)3[Cu(Pyen)] (M′MOF 1) with narrow porosity (<0.56 nm) and an array of pores in the bc crystallographic plane where the adsorbate–adsorbent interactions are maximized by both the presence of open copper centers and overlap of the potential energy fields from pore walls. The H2 and D2 adsorption isotherms for M′MOF 1 at 77.3 and 87.3 K were reversible with virtually no hysteresis. Methods for determination of the isosteric enthalpies of H2 and D2 adsorption were compared. A virial model gave the best agreement (average deviation <1 stand...

Semimetal-functionalised polyoxovanadates.

Abstract: Polyoxovanadates (POVs), known for their wide applicability and relevance in chemical, physical and biological sciences, are a subclass of polyoxometalates and usually self-assemble in aqueous-phase, pH-controlled condensation reactions. Archetypical POVs such as the robust [VO42](12-) polyoxoanion can be structurally, electronically and magnetically altered by heavier group 14 and 15 elements to afford Si-, Ge-, As- or Sb-decorated POV structures (heteroPOVs). These main-group semimetals introduce specific chemically engineered functionalities which cause the generally hydrophilic heteroPOV compounds to exhibit interesting reactivity towards organic molecules, late transition metal and lanthanoid ions. The fully-oxidised (V(V)), mixed-valent (V(V)/V(IV) and V(IV)/V(III)), "fully-reduced" (V(IV)) and "highly-reduced" (V(III)) heteroPOVs possess a number of intriguing properties, ranging from catalytic to molecular magnet characteristics. Herein, we review key developments in the synthetic and structural chemistry as well as the reactivity of POVs functionalised with Si-, Ge-, As- or Sb-based heterogroups.