Metal–Organic Organopolymeric Hybrid Framework by Reversible [2+2] Cycloaddition Reaction

Organic polymers are usually amorphous or possess very low crystallinity. The metal complexes of organic polymeric ligands are also difficult to crystallize by traditional methods because of their poor solubilities and their 3D structures can not be determined by single‐crystal X‐ray crystallography owing to a lack of single crystals. Herein, we report the crystal structure of a 1D Zn^II coordination polymer fused with an organic polymer ligand made in situ by a [2+2] cycloaddition reaction of a six‐fold interpenetrated metal–organic framework. It is also shown that this organic polymer ligand can be depolymerized in a single‐crystal‐to‐single‐crystal (SCSC) fashion by heating. This strategy could potentially be extended to make a range of monocrystalline metal organopolymeric complexes and metal–organic organopolymeric hybrid materials. Such monocrystalline metal complexes of organic polymers have hitherto been inaccessible for materials researchers.     

Structure determination of KScS2, RbScS2 and KLnS2 (Ln = Nd,Sm, Tb,Dy, Ho,Er, Tm and Yb) and crystal–chemical discussion

The title structures of KScS₂ (potassium scandium sulfide), RbScS₂ (rubidium scandium sulfide) and KLnS₂ [Ln = Nd (potassium neodymium sufide), Sm (potassium samarium sulfide), Tb (potassium terbium sulfide), Dy (potassium dysprosium sulfide), Ho (potassium holmium sulfide), Er (potassium erbium sulfide), Tm (potassium thulium sulfide) and Yb (potassium ytterbium sulfide)] are either newly determined (KScS₂, RbScS₂ and KTbS₂) or redetermined. All of them belong to the α‐NaFeO₂ structure type in agreement with the ratio of the ionic radii r³⁺/r⁺. KScS₂, the member of this structural family with the smallest trivalent cation, is an extreme representative of these structures with rare earth trivalent cations. The title structures are compared with isostructural alkali rare earth sulfides in plots showing the dependence of several relevant parameters on the trivalent cation crystal radius; the parameters thus compared are c, a and c/a, the thicknesses of the S—S layers which contain the respective constituent cations, the sulfur fractional coordinates z(S²⁻) and the bond‐valence sums.     

Thermally Triggered Solid‐State Single‐Crystal‐to‐Single‐Crystal Structural Transformation Accompanies Property Changes

The 1D complex [(CuL_0.5H₂O) ? H₂O]_n ( 1 ) (H₄L=2,2′‐bipyridine‐3,3′,6,6′‐tetracarboxylic acid) undergoes an irreversible thermally triggered single‐crystal‐to‐single‐crystal (SCSC) transformation to produce the 3D anhydrous complex [CuL_0.5]_n ( 2 ). This SCSC structural transformation was confirmed by single‐crystal X‐ray diffraction analysis, thermogravimetric (TG) analysis, powder X‐ray diffraction (PXRD) patterns, variable‐temperature powder X‐ray diffraction (VT–PXRD) patterns, and IR spectroscopy. Structural analyses reveal that in complex 2 , though the initial 1D chain is still retained as in complex 1 , accompanied with the Cu‐bound H₂O removed and new O(carboxyl)?Cu bond forming, the coordination geometries around the Cu^II ions vary from a distorted trigonal bipyramid to a distorted square pyramid. With the drastic structural transition, significant property changes are observed. Magnetic analyses show prominent changes from antiferromagnetism to weak ferromagnetism due to the new formed Cu1‐O‐C‐O‐Cu4 bridge. The catalytic results demonstrate that, even though both solid‐state materials present high catalytic activity for the synthesis of 2‐imidazolines derivatives and can be reused, the activation temperature of complex 1 is higher than that of complex 2 . In addition, a possible pathway for the SCSC structural transformations is proposed.     

Defective disordered crystal structure of (2-hydroxyphenyl)diphenylphosphineoxide

A disordered defective crystal structure of (2-hydroxyphenyl)diphenylphosphineoxide (I) has been studied by XRD method. The rhombic structure of I (space group Pna2₁, a = 18.271 Å, b = 8.337 Å, c = 19.629 Å, Z = 8) was solved by a direct method and refined by a full-matrix LSM having taken into account its crystal packing defects (by introducing two additional independent low-populated molecules) to R = 0.060 for all 3517 independent reflections measured (a CAD-4 autodiffractometer, λMoK _α. There are two independent molecules A and B with population 0.90 and two additional independent molecules C and D with population 0.10 in the structure of I.     

Crystallographic report: Dimethyl‐2‐phenylethan‐2‐olamine cyanoborane

The structure of the title compound reveals the geometry around the boron atom to be tetrahedral, and the B? C?N moiety has a bent geometry. Copyright © 2005 John Wiley & Sons, Ltd.     

Crystal structure,shape analysis and bioactivity of new LiI,NaI and MgII complexes with 1,10‐phenanthroline and 2‐(3,4‐dichlorophenyl)acetic acid

Reactions of 1,10‐phenanthroline (phen) and 2‐(3,4‐dichlorophenyl)acetic acid (dcaH) with M_n(CO₃) (M = Li^I, Na^I and Mg^II; n = 1 and 2) in MeOH yield the mononuclear lithium complex aqua[2‐(3,4‐dichlorophenyl)acetato‐κO](1,10‐phenanthroline‐κ²N,N′)lithium(I), [Li(C₈H₅Cl₂O₂)(C₁₂H₈N₂)(H₂O)] or [Li(dca)(phen)(H₂O)] ( 1 ), the dinuclear sodium complex di‐μ‐aqua‐bis{[2‐(3,4‐dichlorophenyl)acetato‐κO](1,10‐phenanthroline‐κ²N,N′)sodium(I)}, [Na₂(C₈H₅Cl₂O₂)₂(C₁₂H₈N₂)₂(H₂O)₂] or [Na₂(dca)₂(phen)₂(H₂O)₂] ( 2 ), and the one‐dimensional chain magnesium complex catena‐poly[[[diaqua(1,10‐phenanthroline‐κ²N,N′)magnesium]‐μ‐2‐(3,4‐dichlorophenyl)acetato‐κ²O:O′] 2‐(3,4‐dichlorophenyl)acetate monohydrate], {[Mg(C₈H₅Cl₂O₂)(C₁₂H₈N₂)(H₂O)₂](C₈H₅Cl₂O₂)·H₂O}_n or {[Mg(dca)(phen)(H₂O)₂](dca)·H₂O}_n ( 3 ). In these complexes, phen binds via an N,N′‐chelate pocket, while the deprotonated dca^? ligands coordinate either in a monodentate (in 1 and 2 ) or bidentate (in 3 ) fashion. The remaining coordination sites around the metal ions are occupied by water molecules in all three complexes. Complex 1 crystallizes in the triclinic space group P with one molecule in the asymmetric unit. The Li⁺ ion adopts a four‐coordinated distorted seesaw geometry comprising an [N₂O₂] donor set. Complex 2 crystallizes in the triclinic space group P with half a molecule in the asymmetric unit, in which the Na⁺ ion adopts a five‐coordinated distorted spherical square‐pyramidal geometry, with an [N₂O₃] donor set. Complex 3 crystallizes in the orthorhombic space group P2₁2₁2₁, with one Mg²⁺ ion, one phen ligand, two dca^? ligands and three water molecules in the asymmetric unit. Both dcaH ligands are deprotonated, however, one dca^? anion is not coordinated, whereas the second dca^? anion coordinates in a bidentate fashion bridging two Mg²⁺ ions, resulting in a one‐dimensional chain structure for 3 . The Mg²⁺ ion adopts a distorted octahedral geometry, with an [N₂O₄] donor set. Complexes 1 – 3 were evaluated against urease and α‐glucosidase enzymes for their inhibition potential and were found to be inactive.     

A new high‐pressure strontium germanate,SrGe2O5

The Sr–Ge–O system has an earth‐scientific importance as a potentially good low‐pressure analog of the Ca–Si–O system, one of the major components in the constituent minerals of the Earth's crust and mantle. However, it is one of the germanate systems that has not yet been fully examined in the phase relations and structural properties. The recent findings that the SrGeO₃ high‐pressure perovskite phase is the first Ge‐based transparent electronic conductor make the Sr–Ge–O system interesting in the field of materials science. In the present study, we have revealed the existence of a new high‐pressure strontium germanate, SrGe₂O₅. Single crystals of this compound crystallized as a co‐existent phase with SrGeO₃ perovskite single crystals in the sample recovered in the compression experiment of SrGeO₃ pseudowollastonite conducted at 6 GPa and 1223 K. The crystal structure consists of germanium–oxygen framework layers stacked along [001], with Sr atoms located at the 12‐coordinated cuboctahedral site; the layers are formed by the corner linkages between GeO₆ octahedra and between GeO₆ octahedra and GeO₄ tetrahedra. The present SrGe₂O₅ is thus isostructural with the high‐pressure phases of SrSi₂O₅ and BaGe₂O₅. Comparison of these three compounds leads to the conclusion that the structural responses of the GeO₆ and GeO₄ polyhedra to cation substitution at the Sr site are much less than that of the SrO₁₂ cuboctahedron to cation substitution at the Ge sites. Such a difference in the structural response is closely related to the bonding nature.     

Synthesis and Crystal Structures of Two Complexes [Mn2(L)2(H2bta)2(H2O)]n and[Cu2(L)(H2bta)0.5(H2O)]n

Two new complexes, [Mn₂(L)₂(H₂bta)₂(H₂O)]_n ( 1 ) and [Cu₂(L)(H₂bta)_0.5(H₂O)]_n ( 2 ) (H₄bta=1,2,4,5‐benzene‐tetracarboxylic acid, L=imidazo[4,5‐f][1,10]phenathroline) were prepared under hydrothermal conditions and their structures determined by single‐crystal X‐ray diffration. The X‐ray diffraction reveals that complex 1 , consisting of two crystallographically independent fragments A1 and A2, displays an interesting 3D supramolecular network constructed with ABAB sequence through hydrogen bonding interactions. In complex 2 , the copper atoms connected by the H₂bta^2? ligands, the chains also are assembled into a 3D honeycomb configuration network formed by moleculars and aromatic π‐π stacking interactions.     

A Chemically Triggered and Thermally Switched Dielectric Constant Transition in a Metal Cyanide Based Crystal

A dielectric constant transition is chemically triggered and thermally switched in (HPy)₂[Na(H₂O)Co(CN)₆] ( 2 , HPy=pyridinium cation) by single‐crystal‐to‐single‐crystal transformation and structural phase transition, respectively. Upon dehydration, (HPy)₂[Na(H₂O)₂Co(CN)₆] ( 1 ) transforms to its semi‐hydrated form 2 , accompanying a transition from a low‐dielectric state to a high‐dielectric state, and vice versa. This dielectric switch is also realized by a structural phase transition in 2 that occurs between room‐ and low‐temperature phases, and which corresponds to high‐ and low‐dielectric states, respectively. The switching property is due to the variation in the environment surrounding the HPy cation, that is, the hydrogen‐bonding interactions and the crystal packing, which exert predominant influences on the dynamics of the cations that transit between the static and motional states.     

Crystal and Molecular Structure of Hexahydro-2-(Nitro-Benzoylmethylene)Pyrimidine

1INTRODUCTIONHeterocyclicketeneaminalsareversatilestartingmaterialsforthesynthesisofawidevarietyofnewheterocyclesandfusedheterocycles.Thus,thesynthesisandre-actionofheterocyclicketeneaminalshavegivenrisetomuchattention[18i.Recentlynitrationofheterocyclicketeneaminalswasstudied[9i.Wehavepreparedhexahydro-2-(nitro-benzoylmethylene)pyrimidi(1).ItscrystalstructurehasbeendeterminedbyX-raydiffractionmethodandthemolecularstructureisdiscussed.2EXPERIMENTALThesinglecrystalofhexahydro-2-(nitr…     

[Co（p—Me—PPA）2（H2O）2]Cl的合成及其催化环己烯氧化反应的研究

环己烯的选择性氧化是一个较难的课题,原冈是环己烯存在两个活性部位易工发生氧化反应：一是烯两基位的氢易被氧化生成环己烯醇和环己烯酮的产物：二是双键易被氧化成环氧化物、环己酮或Ｃ—ＣＸＸ键断裂生成难成酸等。因此人们一直在努力寻找具有高活性,高选择性的催化剂用以催化环己烯的氧化反应［’＊’］。本文合成的Ｋ叶卜＊卜呷Ａ从比０）。厂１,在０。作氧源下ｍ于催化环己烯氧化反应时呈现出较好的转化率和环己烯酮选择性。１【Ｃｏ（Ｐ－Ｍｅ－ＰＰＡ）。（Ｈ。０）。」Ｃ！的合成采ｍ２一毗咙甲酸和ｐ一甲基本胺作原料合成了【…     

Structure of tetra[β‐(1,2,4‐triazole‐l‐yl) propiophenone] dichloro nickel(II) solvate hexahydrate complex: [NiCl2(C2H2N3CH2CH2‐COPh)4]·6H2O

The mononuclear complex, [NiCl₂ (trzCH₂CH₂COPh)₄]·6H₂O (trz =1,2,4‐triazole), was synthesized and its structure was determined by single crystal X‐ray determination. It crystallizes in the monoclinic system, space group P2₁/c, with lattice parameters: a = 0.80391(2) nm, b = 1.08215(2) tun, c = 2.90133(2) nm, β = 94.792 (1)° and Z = 2. Each nickel atom is coordinated by four N atoms of triazole from four β‐(1,2,4‐triazole‐1‐yl)propiophenone ligands and two chloride anions in trans arrangement with octahedral coordination geometry. In addition to the coordinating nickel complex, there are six uncoordinated water molecules. The Ni‐Cl distance is 0.24865(8) nm and the Ni‐N distances are in the range of 0.2072(2) to 0.2099(2) nm, respectively. In the solid state, the title compound forms three dimensional network structure through hydrogen bonds. The intermolecular hydrogen bonds connect the [NiCl₂(C₂H₂N₃CH₂CH₂COPh)₄] and H₂O moieties. The deep green crystals were also examined by elemental analysis, FT‐IR and UV spectra, which are in agreement with the structural data.     

Polymeric zinc ferrocenyl sulfonate as a molecular aspirator for the removal of toxic metal ions

A porous bilayered open coordination polymer [Zn(4,4'-bpy)(2)(FcphSO(3))(2)](n) (1; FcphSO(3)Na=m-ferrocenyl benzenesulfonate), has been assembled from Zn(NO(3))(2), m-ferrocenyl benzenesulfonate, and the bridging ligand 4,4'-bipyridine (4,4'-bpy). Ion-exchange induced products [Cd(0.6)Zn(0.4)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (2), [Zn(0.75)Pb(0.25)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (3), and [Cu(0.5)Zn(0.5)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (4) could be obtained directly by suspending a big single crystal of 1 into concentrated solutions of Cd(NO(3))(2), Pb(NO(3))(2), and Cu(NO(3))(2), respectively. Most importantly, the big single crystal of 1 could be partly regenerated after immersion into concentrated aqueous solutions of Zn(NO(3))(2). On the other hand, powdered 1 could also be used as a metal ion adsorbent because of the well-defined pore size and pore shape. Ion exchange takes place along with the process of ion sorption. The big single crystal of 1 removes harmful metal ions by means of ion exchange, whereas powdered 1 removes toxic metal ions mainly through ion sorption. Also, compound 1 could be employed as a multi-ion analysis fluorescent probe to detect dangerous metal ions, such as Pb(2+), Cd(2+), Ag(+), and Cu(2+). The compounds described in this study may have potential applications in the design of new molecular devices.     

Synthesis and properties of new aromatic polyimides based on 2,5‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐tert‐butylbenzene and various aromatic dianhydrides

A novel, fluorinated diamine monomer, 2,5‐bis(4‐amino‐2‐ trifluoromethylphenoxy)‐tert‐butylbenzene ( II ) was synthesized through the nucleophilic substitution reaction of tert‐butylhydroquinone (t‐BHQ) and 2‐chloro‐5‐nitrobenzotrifluoride in the presence of potassium carbonate to yield the intermediate dinitro compound I , followed by catalytic reduction with hydrazine and Pd/C to afford diamine II . A series of fluorinated polyimides V were prepared from II with various aromatic dianhydrides ( III _a–f ) via the thermal imidization of poly(amic acid). Most of V _a–f could be soluble in amide‐type solvents and even in less polar solvents. These polyimide films showed tensile strengths up to 106 MPa, elongation at break up to 21%, and initial modulus up to 2.1 GPa. The glass‐transition temperature of V was recorded at 245–304 °C, the 10% weight loss temperatures were above 488 °C, and left more than 41% residue even at 800 °C in nitrogen. Low dielectric constants, low moisture absorptions, and higher and light‐colored transmittances were also observed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5424–5438, 2004     

Crystallographic report: Crystal and molecular structure of triphenyltin thiazole‐2‐carboxylate

The tin atom in the title compound is in a distorted C₃O tetrahedral geometry, as the carboxylate ligand is effectively monodentate. Copyright © 2004 John Wiley & Sons, Ltd.