Hydrogen bonding in cyclic imides and amide carboxylic acid derivatives from the facile reaction of cis‐cyclohexane‐1,2‐carboxylic anhydride with o‐ and p‐anisidine and m‐ and p‐aminobenzoic acids

The structures of the open‐chain amide carboxylic acid rac‐cis‐2‐[(2‐methoxyphenyl)carbamoyl]cyclohexane‐1‐carboxylic acid, C₁₅H₁₉NO₄, (I), and the cyclic imides rac‐cis‐2‐(4‐methoxyphenyl)‐3a,4,5,6,7,7a‐hexahydroisoindole‐1,3‐dione, C₁₅H₁₇NO₃, (II), chiral cis‐3‐(1,3‐dioxo‐3a,4,5,6,7,7a‐hexahydroisoindol‐2‐yl)benzoic acid, C₁₅H₁₅NO₄, (III), and rac‐cis‐4‐(1,3‐dioxo‐3a,4,5,6,7,7a‐hexahydroisoindol‐2‐yl)benzoic acid monohydrate, C₁₅H₁₅NO₄·H₂O, (IV), are reported. In the amide acid (I), the phenylcarbamoyl group is essentially planar [maximum deviation from the least‐squares plane = 0.060 (1) Å for the amide O atom] and the molecules form discrete centrosymmetric dimers through intermolecular cyclic carboxy–carboxy O—H...O hydrogen‐bonding interactions [graph‐set notation R₂²(8)]. The cyclic imides (II)–(IV) are conformationally similar, with comparable benzene ring rotations about the imide N—C_ar bond [dihedral angles between the benzene and isoindole rings = 51.55 (7)° in (II), 59.22 (12)° in (III) and 51.99 (14)° in (IV)]. Unlike (II), in which only weak intermolecular C—H...O_imide hydrogen bonding is present, the crystal packing of imides (III) and (IV) shows strong intermolecular carboxylic acid O—H...O hydrogen‐bonding associations. With (III), these involve imide O‐atom acceptors, giving one‐dimensional zigzag chains [graph‐set C(9)], while with the monohydrate (IV), the hydrogen bond involves the partially disordered water molecule which also bridges molecules through both imide and carboxy O‐atom acceptors in a cyclic R₄⁴(12) association, giving a two‐dimensional sheet structure. The structures reported here expand the structural database for compounds of this series formed from the facile reaction of cis‐cyclohexane‐1,2‐dicarboxylic anhydride with substituted anilines, in which there is a much larger incidence of cyclic imides compared to amide carboxylic acids.     

Luminescence Tuning and White‐Light Emission of Co‐doped Ln–Cd–Organic Frameworks

Four new three‐dimensional isostructural lanthanide–cadmium metal–organic frameworks (Ln–Cd MOFs), [LnCd₂(imdc)₂(Ac)(H₂O)₂]?H₂O (Ln=Pr ( 1 ), Eu ( 2 ), Gd ( 3 ), and Tb ( 4 ); H₃imdc=4,5‐imidazoledicarboxylic acid; Ac=acetate), have been synthesized under hydrothermal conditions and characterized by IR, elemental analyses, inductively coupled plasma (ICP) analysis, and X‐ray diffraction. Single‐crystal X‐ray diffraction shows that two Ln^III ions are surrounded by four Cd^II ions to form a heteronuclear building block. The blocks are further linked to form 3D Ln–Cd MOFs by the bridging imdc^3? ligand. Furthermore, the left‐ and right‐handed helices array alternatively in the lattice. Eu–Cd and Tb–Cd MOFs can emit characteristic red light with the Eu^III ion and green light with the Tb^III ion, respectively, while both Gd–Cd and Pr–Cd MOFs generate blue emission when they are excited. Different concentrations of Eu³⁺ and Tb³⁺ ions were co‐doped into Gd–Cd/Pr–Cd MOFs, and tunable luminescence from yellow to white was achieved. White‐light emission was obtained successfully by adjusting the excitation wavelength or the co‐doping ratio of the co‐doped Gd–Cd and Pr–Cd MOFs. These results show that the relative emission intensity of white light for Gd–Cd:Eu³⁺,Tb³⁺ MOFs is stronger than that of Pr–Cd:Eu³⁺,Tb³⁺ MOFs, which implies that the Gd complex is a better matrix than the Pr complex to obtain white‐light emission materials.     

A Terbium Metal–Organic Framework for Highly Selective and Sensitive Luminescence Sensing of Hg2+ Ions in Aqueous Solution

A series of isomorphic lanthanide metal–organic frameworks (MOFs) Ln(TATAB)?(DMF)₄(H₂O)(MeOH)_0.5 (LnTATAB, Ln=Eu, Tb, Sm, Dy, Gd; H₃TATAB=4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoic acid) have been solvothermally synthesized and structurally characterized. Among these MOFs, TbTATAB exhibits good water stability and a high fluorescence quantum yield. Because mercury ions (Hg²⁺) have a high affinity to nitrogen atoms, and the space between multiple nitrogen atoms from triazine and imino groups is suitable for interacting with Hg²⁺ ions, TbTATAB shows highly selective and sensitive detection of Hg²⁺ in aqueous solution with a detection limit of 4.4 nm . Furthermore, it was successfully applied to detect Hg²⁺ ions in natural water samples.     

Water Stability and Luminescence of Lanthanide Complexes of Tripodal Ligands Derived from 1,4,7‐Triazacyclononane: Pyridinecarboxamide versus Pyridinecarboxylate Donors

A series of europium(III) and terbium(III) complexes of three 1,4,7‐triazacyclononane‐based pyridine containing ligands were synthesized. The three ligands differ from each other in the substitution of the pyridine pendant arm, namely they have a carboxylic acid, an ethylamide, or an ethyl ester substituent, i.e., these ligands are 6,6′,6″‐[1,4,7‐triazacyclononane‐1,4,7‐triyltris(methylene)]tris[pyridine‐2‐carboxylic acid] (H₃tpatcn), ‐tris[pyridine‐2‐carboxamide] (tpatcnam), and ‐tris[pyridine‐2‐carboxylic acid] triethyl ester (tpatcnes) respectively. The quantum yields of both the europium(III) and terbium(III) emission, upon ligand excitation, were highly dependent upon ligand substitution, with a ca. 50‐fold decrease for the carboxamide derivative in comparison to the picolinic acid (=pyridine‐2‐carboxylic acid) based ligand. Detailed analysis of the radiative rate constants and the energy of the triplet states for the three ligand systems revealed a less efficient energy transfer for the carboxamide‐based systems. The stability of the three ligand systems in H₂O was investigated. Although hydrolysis of the ethyl ester occurred in H₂O for the [Ln(tpatcnes)](OTf)₃ complexes, the tripositive [Ln(tpatcnam)](OTf)₃ complexes and the neutral [Ln(tpatcn)] complexes showed high stability in H₂O which makes them suitable for application in biological media. The [Tb(tpatcn)] complex formed easily in H₂O and was thermodynamically stable at physiological pH (pTb 14.9), whereas the [Ln(tpatcnam)](OTf)₃ complexes showed a very high kinetic stability in H₂O, and once prepared in organic solvents, remained undissociated in H₂O.     

Real‐Time Detection of Traces of Benzaldehyde in Benzyl Alcohol as a Solvent by a Flexible Lanthanide Microporous Metal–Organic Framework

Luminescent 3D lanthanide metal–organic framework (Ln‐MOF) {[Tb₂(TATAB)₂] ? 4 H₂O ? 6 DMF}_n ( 1 ) was synthesized under solvothermal conditions by using flexible ligand 4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoate (TATAB). A phase transition was observed between low temperature and room temperature. The luminescence of 1 could be enhanced by formaldehyde and quenched efficiently by trace amounts of benzaldehyde in solvents such as benzyl alcohol (0.01–2.0 vol %) and ethanol (0.01–2.5 vol %). This is the first use of a Ln‐MOF as chemical sensor for both formaldehyde and benzaldehyde. The high sensitivity and selectivity of the luminescence response of 1 to benzaldehyde allows it to be used as an excellent sensor for identifying benzaldehyde and provides a simple and convenient method for detecting traces of benzaldehyde in benzyl alcohol based injections. This work establishes a new strategy for detection of benzaldehyde in benzyl alcohol by luminescent MOFs.     

The cocrystal of 3‐hydroxy‐2‐naphthoic acid and 4,4′‐bipyridine

4,4′‐Bipyridine cocrystallizes with 3‐hydroxy‐2‐naphthoic acid in a 1:2 ratio to give a centrosymmetric three‐component supra­molecular adduct, namely 3‐hydroxy‐2‐naphthoic acid–4,4′‐bipyridine (2/1), C₁₁H₈O₃·0.5C₁₀H₈N₂, in which 4,4′‐bipyridine is located on an inversion center. The pyridine–carboxylic acid heterosynthon generates an infinite one‐dimensional hydrogen‐bonded chain viaπ–π inter­actions between naphthyl and 4,4′‐bipyridine groups. The one‐dimensional chains are further assembled into a three‐dimensional network by weak C—H⋯π inter­actions between pyridyl and naphthyl rings, and C—H⋯O inter­actions between 3‐hydroxy‐2‐naphthoic acid mol­ecules.     

Synthesis,Characterization and Photoluminescence of Lanthanide Metal‐organic Frameworks,Constructed from Triangular 4,4′,4″‐s‐triazine‐1,3,5‐triyl‐p‐aminobenzoate Ligands

Eight isomorphous metal‐organic frameworks: [Ln₂(TATAB)₂(H₂O)(DMA)₆]·5H₂O (Ln = Sm ( 1 ), Eu ( 2 ), Gd ( 3 ), Tb ( 4 ), Dy ( 5 ), Er ( 6 ), Tm ( 7 ), Yb ( 8 )); TATAB = 4,4′,4″‐s‐triazine‐1,3,5‐triyl‐p‐aminobenzoate, DMA = N,N‐dimethylacetamide), were synthesized by the self‐assembly of lanthanide ions, TATAB, DMA and H₂O. Single‐crystal X‐ray crystallography reveals they are three dimensional frameworks with 2‐fold interpenetration. Solid‐state photoluminescence studies indicate ligand‐to‐metal energy transfer is more efficient for compounds 2 and 4 which exhibit intense characteristic lanthanide emissions at room temperature.     

A self‐penetrated three‐dimensional zinc(II) coordination framework based on 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoic acid and 1,3‐bis[(imidazol‐1‐yl)methyl]benzene ligands: synthesis,structure and properties

With the rapid development of metal–organic frameworks (MOFs), a variety of MOFs and their derivatives have been synthesized and reported in recent years. Commonly, multifunctional aromatic polycarboxylic acids and nitrogen‐containing ligands are employed to construct MOFs with fascinating structures. 4,4′,4′′‐(1,3,5‐Triazine‐2,4,6‐triyl)tribenzoic acid (H₃TATB) and the bidentate nitrogen‐containing ligand 1,3‐bis[(imidazol‐1‐yl)methyl]benzene (bib) were selected to prepare a novel Zn^II‐MOF under solvothermal conditions, namely poly[[tris{μ‐1,3‐bis[(imidazol‐1‐yl)methyl]benzene}bis[μ₃‐4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoato]trizinc(II)] dimethylformamide disolvate trihydrate], {[Zn₃(C₂₄H₁₂N₃O₆)₂(C₁₄H₁₄N₄)₃]·2C₃H₇NO·3H₂O}_n ( 1 ). The structure of 1 was characterized by single‐crystal X‐ray diffraction, IR spectroscopy and powder X‐ray diffraction. The properties of 1 were investigated by thermogravimetric and fluorescence analysis. Single‐crystal X‐ray diffraction shows that 1 belongs to the monoclinic space group Pc. The asymmetric unit contains three crystallographically independent Zn^II centres, two 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoate (TATB^3?) anions, three complete bib ligands, one and a half free dimethylformamide molecules and three guest water molecules. Each Zn^II centre is four‐coordinated and displays a distorted tetrahedral coordination geometry. The Zn^II centres are connected by TATB^3? anions to form an angled ladder chain with large windows. Simultaneously, the bib ligands link Zn^II centres to give a helical Zn–bib–Zn chain. Furthermore, adjacent ladders are bridged by Zn–bib–Zn chains to form a fascinating three‐dimensional self‐penetrated framework with the short Schläfli symbol 6⁵·7·8¹³·9·10. In addition, the luminescence properties of 1 in the solid state and the fluorescence sensing of metal ions in suspension were studied. Significantly, compound 1 shows potential application as a fluorescent sensor with sensing properties for Zr⁴⁺ and Cu²⁺ ions.     

A three‐dimensional polymeric potassium complex of 5‐sulfonobenzene‐1,2,4‐tricarboxylic acid: poly[μ‐aqua‐aqua‐μ9‐(2,4‐dicarboxy‐5‐sulfonatobenzoato)‐dipotassium(I)]

The asymmetric unit in the structure of the title compound, [K₂(C₉H₄O₉S)(H₂O)₂]_n, consists of two eight‐coordinated K^I cations, one 2,4‐dicarboxy‐5‐sulfonatobenzoate dianion (H₂SBTC²⁻), one bridging water molecule and one terminal coordinated water molecule. One K^I cation is coordinated by three carboxylate O atoms and three sulfonate O atoms from four H₂SBTC²⁻ ligands and by two bridging water molecules. The second K^I cation is coordinated by four sulfonate O atoms and three carboxylate O atoms from five H₂SBTC²⁻ ligands and by one terminal coordinated water molecule. The K^I cations are linked by sulfonate groups to give a one‐dimensional inorganic chain with cage‐like K₄(SO₃)₂ repeat units. These one‐dimensional chains are bridged by one of the carboxylic acid groups of the H₂SBTC²⁻ ligand to form a two‐dimensional layer, and these layers are further linked by the remaining carboxylate groups and the benzene rings of the H₂SBTC²⁻ ligands to generate a three‐dimensional framework. The compound displays a photoluminescent emission at 460 nm upon excitation at 358 nm. In addition, the thermal stability of the title compound has been studied.     

Assembly of Framework‐Isomeric 4 d–4 f Heterometallic Metal–Organic Frameworks with Neutral/Anionic Micropores and Guest‐Tuned Luminescence Properties

Framework‐isomeric three‐dimensional (3D) Cd–Ln heterometallic metal–organic frameworks (HMOFs), {[Ln₂(ODA)₆Cd₃(H₂O)₆] ? 6 H₂O}_n (Ln=Gd ( 1 a ) and Tb ( 1 b ), ODA=oxydiacetic acid) and {[Cd(H₂O)₆] ? [Ln₂(ODA)₆Cd₂] ? H₂O}_n (Ln=Gd ( 2 a ), Tb ( 2 b )), with neutral and anionic pores, respectively, were designed based on a lanthanide metalloligand strategy and synthesized by using a stepwise assembly and a hydrothermal method. Luminescence studies revealed that 1 b and 2 b can act as luminescent metal–organic frameworks and their light‐emitting properties can be modulated by small guest molecules and the manganese counterion, respectively.     

The N‐Arylamino Conjugation Effect in the Photochemistry of Fluorescent Protein Chromophores and Aminostilbenes

To understand the nonradiative decay mechanism of fluorescent protein chromophores in solutions, a systematic comparison of a series of (Z)‐4‐(N‐arylamino)benzylidene‐2,3‐imidazolinones (ABDIs: 2P , 2PP , 2OM , and 2OMB ) and the corresponding trans‐4‐(N‐arylamino)‐4′‐cyanostilbenes (ACSs: 1P , 1PP , 1OM , and 1OMB ) was performed. We have previously shown that the parameter Φ_f+2 Φ_tc, in which Φ_f and Φ_tc are the quantum yields of fluorescence and trans→cis photoisomerization, respectively, is an effective probe for evaluating the contribution of twisted intramolecular charge transfer (TICT) states in the excited decays of trans‐aminostilbenes, including the push–pull ACSs. One of the criteria for postulating the presence of a TICT state is Φ_f+2 Φ_tc?1.0, because its formation is decoupled with the C?C bond (τ) torsion pathway and its decay is generally nonradiative. Our results show that the same concept also applies to ABDIs 2 with the parameter Φ_f+2 Φ_ZE in which Φ_ZE is the quantum yield of Z→E photoisomerization. We conclude that the τ torsion rather than the C? C bond (φ) torsion is responsible for the nonradiative decays of ABDIs 2 in aprotic solvents (hexane, THF, acetonitrile). The phenyl‐arylamino C? N bond (ω) torsion that leads to a nonradiative TICT state is important only for 2OM in THF and acetonitrile. If the solvent is protic (methanol and 10–20 % H₂O in THF), a new nonradiative decay channel is present for ABDIs 2 , but not for ACSs 1 . It is attributed to internal conversion (IC) induced by solvent (donor)–solute (acceptor) hydrogen‐bonding (HB) interactions. The possible HB modes and the concept of τ torsion‐coupled proton transfer are also discussed.     

2D l‐Di‐toluoyl‐tartaric acid Lanthanide Coordination Polymers: Toward Single‐component White‐Light and NIR Luminescent Materials

A series of five l ‐di‐p‐toluoyl‐tartaric acid (l ‐DTTA) lanthanide coordination polymers, namely {[Ln₄K⁴ L₆(H₂O)_x]?yH₂O}_n, [Ln=Dy ( 1 ), x=24, y=12; Ln=Ho ( 2 ), x=23, y=12; Ln=Er ( 3 ), x=24, y=12; Ln=Yb ( 4 ), x=24, y=11; Ln=Lu ( 5 ), x=24, y=12] have been isolated by simple reactions of H₂L (H₂L= L ‐DTTA) with LnCl₃?6 H₂O at ambient temperature. X‐ray crystallographic analysis reveals that complexes 1 – 5 feature two‐dimensional (2D) network structures in which the Ln³⁺ ions are bridged by carboxylate groups of ligands in two unique coordinated modes. Luminescent spectra demonstrate that complex 1 realizes single‐component white‐light emission, while complexes 2 – 4 exhibit a characteristic near‐infrared (NIR) luminescence in the solid state at room temperature.     

Cyclic imides and an open‐chain amide carboxylic acid from the facile reaction of cis‐cyclohexane‐1,2‐carboxylic anhydride with the isomeric monofluoroanilines

The structures of the cyclic imides cis‐2‐(2‐fluorophenyl)‐3a,4,5,6,7,7a‐hexahydroisoindole‐1,3‐dione, C₁₄H₁₄FNO₂, (I), and cis‐2‐(4‐fluorophenyl)‐3a,4,5,6,7,7a‐hexahydroisoindoline‐1,3‐dione, C₁₄H₁₄FNO₂, (III), and the open‐chain amide acid rac‐cis‐2‐[(3‐fluorophenyl)carbamoyl]cyclohexane‐1‐carboxylic acid, C₁₄H₁₆FNO₃, (II), are reported. Cyclic imides (I) and (III) are conformationally similar, with comparable ring rotations about the imide N—C_ar bond [the dihedral angles between the benzene ring and the five‐membered isoindole ring are 55.40 (8)° for (I) and 51.83 (7)° for (III)]. There are no formal intermolecular hydrogen bonds involved in the crystal packing of either (I) or (III). With the acid (II), in which the meta‐related F‐atom substituent is rotationally disordered (0.784:0.216), the amide group lies slightly out of the benzene plane [the interplanar dihedral angle is 39.7 (1)°]. Intermolecular amide–carboxyl N—H...O hydrogen‐bonding interactions between centrosymmetrically related molecules form stacks extending down b, and these are linked across c by carboxyl–amide O—H...O hydrogen bonds, giving two‐dimensional layered structures which lie in the (011) plane. The structures reported here represent examples of compounds analogous to the phthalimides or phthalanilic acids and have little precedence in the crystallographic literature.     

Three Lanthanide Metal‐Organic Frameworks Based on an Ether‐Decorated Polycarboxylic Acid Linker: Luminescence Modulation,CO2 Capture and Conversion Properties

Three new isostructural 3D lanthanide metal–organic frameworks (Ln‐MOFs), {H[LnL(H₂O)]?2 H₂O}_n ( 1‐Ln ) (Ln=Eu³⁺, Gd³⁺ and Tb³⁺), based on infinite lanthanide‐carboxylate chains were constructed by employing an ether‐separated 5,5′‐oxydiisophthalic acid (H₄L) ligand under solvothermal reaction. 1‐Eu and 1‐Tb exhibit strong red and green emission, respectively, through the antenna effect, as demonstrated through a combination of calculation and experimental results. Moreover, a series of dichromatic doped 1‐Eu_xTb_y MOFs were fabricated by introducing different concentrations of Eu³⁺ and Tb³⁺ ions, and they display an unusual variation of luminescent colors from green, yellow, orange to red. 1‐Eu with channels decorated by ether O atoms and the open metal sites displays good performance for CO₂ capture and conversion between CO₂ and epoxides into cyclic carbonates.     

A Series of Lanthanide Metal–Organic Frameworks with Interesting Adjustable Photoluminescence Constructed by Helical Chains

Based on the isonicotinic acid (HIN=pyridine‐4‐carboxylic acid), seven lanthanide metal–organic frameworks (MOFs) with the formula [Ln(IN)₂L] (Ln=Eu ( 1 ), Tb ( 2 ), Er ( 3 ), Dy ( 4 ), Ho ( 5 ), Gd ( 6 ), La ( 7 ), L=OCH₂CH₂OH) have been synthesized by mixing Ln₂O₃ with HIN under solvothermal conditions, and characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction, infrared spectroscopy, and fluorescence spectroscopy. Crystal structural analysis shows that compounds 1–6 are isostructural, crystallize in a chiral space group P2₁2₁2₁, whereas compound 7 crystallizes in space group C2/c. Nevertheless, they all consist of new intertwined chains. Simultaneously, on the basis of the above‐mentioned compounds, we have realized a rational design strategy to form the doped Ln MOFs [(Eu_xTb_1?x)(IN)₂L] (x=0.35 ( 8 ), x=0.19 ( 9 ), x=0.06 ( 10 )) by utilizing Tb^III as the second “rare‐earth metal”. Interestingly, the photoluminescence of [(Eu_xTb_1?x)(IN)₂L] are not only adjustable by the ratios of Eu/Tb, but also temperature or excitation wavelength.     

A family of functional Ln‐organic framework constructed by iodine‐substituted aromatic polycarboxylic acid for turn‐off sensing of UO22+

With the rapid development of nuclear energy, one of the main constraints restricting the development of nuclear energy is the long‐term safe disposal of strong uranium waste. Here it is a great significance that we use four new synthetic Ln (III)‐based coordination polymers to test the uranium solution. In this study, four three‐dimensional coordination polymers 1 – 4 (CPs‐( 1–4 ); Ln = Eu, Gd, Sm, Nd) were successfully synthesized through 1:1 complexation of Ln (NO₃)₃·6H₂O with poly‐carboxylic acid ligand H₃TIBTC (2,4,6‐Triiodo‐1,3,5‐benzene tricarboxylic acid) which contains substituents of the carboxylic acid group and halogen atom, respectively. Based on the ligand being excellent fluorescent properties in the solution, it prompted us to further study the fluorescence properties of the coordination polymers. Experimental results show that the coordination polymers are favorable materials for the simultaneous selective detection uranium solution from water, being potentially useful in monitoring water quality and treating uranium‐wastewater.     

Three 4,7‐diaryl‐2‐ethylsulfanylpyrazolo[1,5‐a][1,3,5]triazines

The molecular dimensions of 2‐ethylsulfanyl‐7‐(4‐methylphenyl)‐4‐phenylpyrazolo[1,5‐a][1,3,5]triazine, C₂₀H₁₈N₄S, (I), 7‐(4‐chlorophenyl)‐2‐ethylsulfanyl‐4‐phenylpyrazolo[1,5‐a][1,3,5]triazine, C₁₉H₁₅ClN₄S, (II), and 4,7‐bis(4‐chlorophenyl)‐2‐(ethylsulfanyl)pyrazolo[1,5‐a][1,3,5]triazine, C₁₉H₁₄Cl₂N₄S, (III), show evidence for some aromatic delocalization in the pyrazole rings. The conformations adopted by the ethylsulfanyl substituents are different in all three compounds. There are no hydrogen bonds in any of the crystal structures, but pairs of molecules in (II) and (III) are linked into centrosymmetric dimers by π‐stacking interactions.     

An X‐ray powder diffraction study of cis‐dichloridobis(2‐methyl‐2H‐tetrazol‐5‐amine‐κN4)platinum(II), a tetrazole‐containing analogue of cisplatin

The structure of the title compound, cis‐[PtCl₂(C₂H₅N₅)₂], was analysed using in‐house X‐ray powder diffraction data at room temperature. The structure was solved by direct methods and refined using Rietveld analysis. A slightly distorted square‐planar coordination geometry is formed around the Pt atom by two Cl atoms and two ring N atoms of the 2‐methyl‐2H‐tetrazol‐5‐amine ligands, which are in a cis configuration. The planes of the tetrazole rings are inclined at 79.7 (7) and 73.8 (6)° with respect to the coordination plane, with their substituents oriented in such a way that the complex as a whole has approximate C₂ symmetry. Intermolecular N—H...Cl hydrogen bonds mediate the formation of a three‐dimensional supramolecular network.     

Hydrothermal Syntheses,Crystal Structures and Properties of Two Novel 3‐D Lanthanide(III) Coordination Polymers Constructed with Mixed Heterocyclic Carboxylic Acid

The hydrothermal reactions of Ln₂O₃ (Ln = Nd and Eu) with pyridine‐2,5‐dicarboxylic acid (H₂pydc) resulted in the formation of two isomorphic three‐dimensional (3D) polymeric Ln^III complexes, [Ln(pydc)(nic)·H₂O]_n (Ln = Nd( 1 ) and Eu( 2 )), in which nic (nicotinate; also named as pyridine‐2‐carboxylic acid) might have been formed from the pydc ligands through the C–C bond cleavage and CO₂ molecules releasing. Pydc ligands bridge lanthanide centers to form the three‐dimensional framework featuring hexagonal channels along the axis a which are occupied by bridging nic anions and mono‐coordinated water molecules. From the topological point of view, two three‐dimensional nets are binodal with six‐ and three‐connected nodes, which display a distorted rutile (4.6²)₂(4²·6¹⁰·8³) topology. Magnetic measurements (2‐300 K) reveal that all polymers possess weak antiferromagnetic property. A strong fluorescence emission spectrum of compound 2 was observed.     

Microporous La–Metal–Organic Framework (MOF) with Large Surface Area

A microporous La–metal‐organic framework (MOF) has been synthesized by the reaction of La(NO₃)₃ ? 6 H₂O with a ligand 4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoate (TATAB) featuring three carboxylate groups. Crystal structure analysis confirms the formation of 3D MOF with hexagonal micropores, a Brunauer–Emmett—Teller (BET) surface area of 1074 m² g^?1 and high thermal and chemical stability. The CO₂ adsorption capacities are 76.8 cm³ g^?1 at 273 K and 34.6 cm³ g^?1 at 293 K, a highest measured CO₂ uptake for a Ln–MOFs.