Poly[μ2-aqua-aqua-μ4-pyridine-2,4-dicarboxyl­ato-strontium]

In the title polymeric complex, [Sr(C7H3NO4)(H2O)2]n, the SrII atom is eight-coordinated by four O atoms and one N atom of four pyridine-2,4-dicarboxyl­ate (py-2,4-dc) ligands and three O atoms of three coordinated water mol­ecules in a dodeca­hedral geometry. These units are connected via the carboxyl­ate O atoms and water mol­ecules, building polymeric layers parallel to (100). In the crystal structure, non-covalent inter­actions consisting of O—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distances = 3.862 (17) and 3.749 (17) Å] connect the various components, forming a three-dimensional structure

Sensitizing, sensing and chemical separation of Tb(III) ions: All in a novel T copper metal-organic framework

The importance of rare earth elements in high-tech materials has promoted the necessity to develop new materials for sensing and separating them. Luminescent metal-organic frameworks (MOFs) due to their promising applications as functional materials for chemical sensing and separation, which upon introducing analytes create multi-responsive systems, have been receiving great attention by scientists. In this regard, we have designed and synthesized a novel three-dimensional copper framework, [Cu2(3,4-pydc)2(H2O)5]n.2nH2O (1; 3,4-H2pydc = 3,4-pyridine dicarboxylic acid), in ambient condition with an interesting topology and potential application as a cation exchange material. Upon Tb3+ ions uptake, compound 1 exhibited the antenna effect to sensitize Tb3+ ions and its fluorescent emission was enhanced. It also showed selective sensing ability based on turn-on fluorescence response towards Tb3+ ions, in a mixture of main and transition metal ions and Tb3+ ions. Furthermore, the results showed that the Tb3+ ion exchange process is reversible. Therefore, compound 1 is a promising multifunctional luminescent MOF for simultaneous sensing and chemical separation of Tb3+ ions which is an advantage over the previously used MOFs in this regard. Furthermore, the reusability experiment demonstrated that 1 can be utilized for long-term detection and separation of Tb3+ ions

Sonochemical synthesis of two nanoscale Co(II) coordination compounds: Facile fabrication of Co3O4 nanoparticles with various morphologies

Two new nanoscale cobalt(II) coordination compounds, (adH)3[Co(Hpzdc)(pzdc)2].6H2O (1) and [Co(pzdc)2(H2O)2]n (2) (where H2pzdc is 2,3-pyrazinedicarboxylic acid and ad is adenine), were synthesized using a sonochemical process and characterized via scanning electron microscopy (SEM), X-ray powder diffraction (XRPD) and FT-IR spectroscopy. The structural characterization of 1 through single crystal X-ray diffraction revealed that it consists of a 0D coordination compound in which Co(II) ion is six-coordinated by two pzdc2- and one pzdcHligands. Compound 2 however, is a 1D coordination polymer (CP) and was found to be a perfect precursor for Co3O4 nanoparticles. Changes in the morphology and size of the nanoparticles have been induced by altering the calcination temperature in the range of 400 to 850 °C. Furthermore, the magnetic behavior of 2 was studied and compared with its single crystal counterpart

Sensitizing, sensing and chemical separation of Tb(III) ions: All in a novel T copper metal-organic framework

The importance of rare earth elements in high-tech materials has promoted the necessity to develop new materials for sensing and separating them. Luminescent metal-organic frameworks (MOFs) due to their promising applications as functional materials for chemical sensing and separation, which upon introducing analytes create multi-responsive systems, have been receiving great attention by scientists. In this regard, we have designed and synthesized a novel three-dimensional copper framework, [Cu2(3,4-pydc)2(H2O)5]n.2nH2O (1; 3,4-H2pydc = 3,4-pyridine dicarboxylic acid), in ambient condition with an interesting topology and potential application as a cation exchange material. Upon Tb3+ ions uptake, compound 1 exhibited the antenna effect to sensitize Tb3+ ions and its fluorescent emission was enhanced. It also showed selective sensing ability based on turn-on fluorescence response towards Tb3+ ions, in a mixture of main and transition metal ions and Tb3+ ions. Furthermore, the results showed that the Tb3+ ion exchange process is reversible. Therefore, compound 1 is a promising multifunctional luminescent MOF for simultaneous sensing and chemical separation of Tb3+ ions which is an advantage over the previously used MOFs in this regard. Furthermore, the reusability experiment demonstrated that 1 can be utilized for long-term detection and separation of Tb3+ ions

4,4′-Bipyridinium bis­(μ-4-oxo-1,4-dihydropyridine-2,6-dicarboxyl­ato)bis­[aqua­hydroxido­anti­monate(III)] dihydrate

The title compound, (C10H10N2)[Sb2(C7H2NO5)2(OH)2(H2O)2]·2H2O, consists of a binuclear anion, a diprotonated 4,4′-bipyridinium cation and two uncoordinated water mol­ecules. Each SbIII atom is six-coordinated by one chelating 4-oxidopyridine-2,6-dicarboxyl­ate ligand, one water mol­ecule, one OH group and one bridging O atom from a neighboring carboxyl­ate group in a distorted penta­gonal-pyramidal geometry, with the OH group at the apical position. The two pyridine rings in the bipyridinium cation are twisted with respect to each other, making a dihedral angle of 22.7 (1)°. The cations are connected to the anions by N—H⋯O hydrogen bonds, forming a chain. The coordinated water mol­ecules form hydrogen bonds with the oxido O atoms of the anion, building a two-dimensional sheet, which is further connected into a three-dimensional structure by O—H⋯O and C—H⋯O hydrogen bonds and C=O⋯π inter­actions [O⋯centroid distances = 3.1785 (17), 3.4737 (19) and 3.5685 (19) Å]

4-(4-Pyrid­yl)pyridinium bis­(pyridine-2,6-dicarboxyl­ato)ferrate(III) tetra­hydrate

In the title compound, (C10H9N2)[Fe(C7H3NO4)2]·4H2O or (bpyH)[Fe(pydc)2]·4H2O, the asymmetric unit contains an [Fe(pydc)2]− (pydcH2= pyridine-2,6-dicarboxylic acid) anion, a protonated 4,4′-bipyridine as a counter-ion, (bpyH)+, and four uncoordinated water mol­ecules. The anion is a six-coordinate complex with a distorted octa­hedral geometry around the FeIII atom. A wide range of non-covalent inter­actions, i.e. O—H⋯O, O—H⋯N and N—H⋯O hydrogen bonds, ion pairing, C—O⋯π [3.431 (2) Å] and C—H⋯π stacking inter­actions result in the formation of a three-dimensional network structure

2-(2-Pyrid­yl)pyridinium bis­(pyridine-2,6-dicarboxyl­ato-κ3 O,N,O′)aluminate(III) trihydrate

The title compound, (C10H9N2)[Al(C7H3NO4)2]·3H2O or (2,2′-bipyH)[Al(pydc)2]·3H2O (where 2,2′-bipy is 2,2′-bipyridine and pydcH2 is pyridine-2,6-dicarboxylic acid), was synthesized by the reaction of aluminium(III) nitrate nona­hydrate with pyridine-2,6-dicarboxylic acid and 2,2′-bipyridine in a 1:2:4 molar ratio in aqueous solution. This compound is composed of an anionic complex, [Al(pydc)2]−, a protonated 2,2′-bipyridine mol­ecule as a counter-ion, (2,2′-bipyH)+, and three uncoordinated water mol­ecules. The anion is a six-coordinate complex, with the AlIII atom in a distorted octa­hedral geometry coordinated by two tridentate pyridine-2,6-dicarboxyl­ate groups. In the crystal structure, inter­molecular O—H⋯O, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds, π–π stacking between two aromatic rings [centroid–centroid distance = 3.827 (10) Å], and C=O⋯π stacking [with distances of 3.2311 (13), 3.4924 (14) and 3.5731 (13) Å], connect the various components to form a supra­molecular structure

Dopamine sensing based on ultrathin fluorescent metal−organic nanosheets

The importance of dopamine (DA) detection as a biomarker for several diseases, especially Parkinson''s disease, has persuaded scientists to develop new nanomaterials for efficient sensing of DA in clinical samples. Ultrathin metal-organic nanosheets due to their exceptional thickness, large surface area, and flexibility are endowed with many accessible active sites and optimal surface interaction with the target analyte molecules. In this regard, a novel layered fluorescent metal-organic nanomaterial with a honeycomb topology based on europium, [Eu(pzdc)(Hpzdc)(H2O)]n (ECP) (H2pzdc = 2,3-pyrazine dicarboxylic acid), was synthesized. X-ray crystallography revealed that the 3D supramolecular architecture of ECP is constructed from noncovalent interactions of coordinated water molecules between the 2D layers along the b axis. These layers that are only ∼4 nm thick were conveniently separated through ultrasound-induced liquid phase exfoliation. Optical studies show that the reduction of ECP thickness enhances the fluorescence intensity and serves as an efficient optical marker for DA detection. ECP nanoflakes exhibited fast response and high selectivity for DA detection in clinical samples. Good linearity for DA detection in the range of 0.1-10 μM with a detection limit of 21 nM proves the potential of ECP nanoflakes in DA sensing applications