Piperazinediium bis­(2-carboxy­pyridine-3-carboxyl­ate)

The asymmetric unit of the title salt, C4H12N2 2+·2C7H4NO4 − or pipzH2 2+·2(py-2,3-dcH−), prepared by a reaction between pyridine-2,3-dicarboxylic acid (py-2,3-dcH2) and piperazine (pipz), contains a monoanion and half of a centrosymmetric dication. The anionic fragment individually has two intra­molecular hydrogen bonds, an almost linear O—H⋯O bond between two carboxyl­ate groups and a C—H⋯O bond between the aromatic ring and carboxyl­ate group. Other O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds are responsible for three-dimensional expansion of the structure

Hexa­kis­(dimethyl sulfoxide-κO)thallium(III) trinitrate

The title compound, [Tl(C2H6OS)6](NO3)3, consists of six dimethyl sulfoxide (DMSO) mol­ecules coordinated to a TlIII atom, which lies on a axis, and three nitrate anions (3. symmetry) to neutralize the charge. The coordination polyhedron around the TlIII atom is octa­hedral, defined by six O atoms of the DMSO mol­ecules. In the crystal structure, C—H⋯O hydrogen bonds are observed. One of the nitrate groups exhibits half-occupation

4,4′-Bipyridinium bis­(2-carboxy­pyridine-3-carboxyl­ate)

The title salt, C10H10N2 2+·2C7H4NO4 − or (4,4′-bpyH2)(py-2,3-dcH)2, prepared by the reaction between pyridine-2,3-dicarboxylic acid (py-2,3-dcH2) and 4,4′-bipyridine (4,4′-bpy), consists of two anions and one centrosymmetric dication. In the crystal, there are two strong O—H⋯O hydrogen bonds involving the two carboxyl­ate groups, with an O⋯O distance of 2.478 (1) Å, and an N—H⋯N hydrogen bond between the anion and cation, with an N⋯N distance of 2.743 (1) Å. These inter­actions, along with other O—H⋯O and C—H⋯O hydrogen bonds, π–π stacking [centroid–centroid distances 3.621 (7) and 3.612 (7) Å] and ion pairing, lead to the formation of the three-dimensional structure

catena-Poly[[triaqua­cadmium(II)]-μ-pyridine-2,3-dicarboxyl­ato-κ3 N,O 2:O 3]

The title polymeric compound, [Cd(C7H3NO4)(H2O)3]n or [Cd(py-2,3-dc)(H2O)3]n, where py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid, was obtained by the reaction of cadmium(II) nitrate hexa­hydrate with (pipzH2)(py-2,3-dc) as a proton-transfer compound in aqueous solution (pipz is piperazine). The mol­ecular structure shows that only the anionic fragment of the starting proton-transfer compound is present in the complex, while the (pipzH2)2+ dication has been lost. Each (py-2,3-dc)2− ligand bridges two CdII atoms in two different coordination modes, i.e. one end acts as a monodentate and the other end as a bidentate ligand. The three remaining coordination sites on the metal center are occupied by water mol­ecules. The geometric arrangement of the six donor atoms around the CdII atom is distorted octa­hedral. In the crystal structure, O—H⋯O and C—H⋯O hydrogen bonds play an important role in stabilizing the supra­molecular structure

Development of a wirelessly controlled drug delivery implantable chip based on IPMC actuator for cancer treatment

In the present study, the novel implantable drug delivery chip was designed by silicon reservoir and Ionic Polymer Metal Composite (IPMC) actuator integration. The whole design was tested to be biocompatible. The reservoir was developed by high technique silicon lithography and the IPMC strip was attached as the gate of the drug reservoir. The IPMC actuation and subsequently the drug release was controlled by a manipulated communication system based on transmitter and receiver circuits, designed for wireless power transmission. Electromagnetic waves with 2 MHz frequency were for power transmission. The wireless transmission is on the order of 5 cm due to the chip potential to get implanted in the patient's body, near the cancerous organ. Introduction: Drug delivery systems are divided into two main categories: passive systems and active systems, where the drug release is controlled by an external source. The active systems involve remote controlled drug delivery chips based on silicon, a remarkable technology, which releases a certain dose of drug on demand from outside the body. Both systems are designed to facilitate cancer treatment and prevent patients from getting involved with the chemotherapy's side effects. Methods and Results:IPMC was fabricated by electroless deposition of nafion as a smart polymer with the ability to bend in low applied voltages. The prepared IPMC was attached to an etched silicon as a single drug reservoir chip. The transmitter section included a microcontroller, a driver, an amplifier and a coil. Electromagnetic waves generated in the transmitter section were captured by the receiver section, converted to electrical voltage and transferred toIPMC actuator to unseal the drug reservoir.Figure 1 shows the schematic of the drug delivery chip with wireless communications. Conclusions:The single reservoir, wirelessly controlled drug delivery chip was designed using IPMC actuator as the gate of the reservoir. The drug was released on demand by generating electromagnetic waves that were converted to electrical voltage and transferred to IPMC actuator in receiver section on the chip

Bis(2,4,6-triamino-1,3,5-triazin-1-ium) tris­(pyridine-2,6-dicarboxyl­ato)­zirconate(IV) tetra­hydrate

The title compound, (C3H7N6)2[Zr(C7H3NO4)3]·4H2O or (tataH)2[Zr(pydc)3]·4H2O (tata is 2,4,6-triamino-1,3,5-triazine and pydcH2 is pyridine-2,6-dicarboxylic acid), was obtained by reaction between pydcH2, tata and zirconyl chloride octa­hydrate in aqueous solution. In the structure, the ZrIV atom is nine-coordinated by three (pydc)2− groups, resulting in an anionic complex which is balanced by two (tataH)+ cations. One of the NH2 groups shows positional disorder, with site occupation factors of 0.60 and 0.40. There are four uncoordinated water mol­ecules (one of which is disordered with occupation factors of 0.70 and 0.30) in the crystal structure. Several inter­molecular inter­actions, including O—H⋯O, O—H⋯N, N—H⋯O, N—H⋯N, C—H⋯O and C—H⋯N hydrogen bonds, a C—O⋯π inter­action [O⋯Cg 3.89, C⋯Cg 4.068 (3) Å; C—O⋯Cg 89° where Cg is the centroid of the triamine ring], and π–π stacking [with centroid–centroid distances of 3.694 (2) and 3.802 (2) Å] are also present

Bis(piperazinediium) benzene-1,2,4,5-tetra­carboxyl­ate hexa­hydrate

The title compound, 2C4H12N2 2+·C10H2O8 4−·6H2O or (pipzH2)2(btc)·6H2O, was formed from the reaction between benzene-1,2,4,5-tetra­carboxylic acid (btcH4) as a proton donor and piperazine (pipz) as a proton acceptor. A variety of O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, as well as C—H⋯π inter­actions, are present in the crystal structure. Two water O atoms are each disordered over two positions; for both the site occupany factors are ca 0.66 and 0.34

Piperazine-1,4-diium pyridine-2,3-dicarboxyl­ate methanol monosolvate1

The title solvated molecular salt, C4H12N2 2+·C7H3NO4 2−·CH3OH or (pipzH2)(py-2,3-dc)·MeOH, was prepared by the reaction of pyridine-2,3-dicarb­oxy­lic acid (py-2,3-dcH2) and piperazine (pipz) in methanol (MeOH) as solvent. One of the two carboxylate groups of the acid fragment is nearly perpendicular to the pyridine ring and the other is almost in its plane [C—C—C—O torsion angles = −85.50 (11) and 88.07 (11)° and N—C—C—O torsion angles = −176.31 (8) and 5.41 (13)°]. In the crystal, the components are linked by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, generating a three-dimensional network

The effect of cationic surfactant on the structure, morphology and optical band gap of ferrites synthesized by a microwave sol–gel auto-combustion method

Cu and Ni ferrites as the semiconductor materials were synthesized by a microwave sol-gel auto-combustion method. Two cationic surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), were applied and the influence of surfactants on the properties of the Cu and Ni ferrite particles was studied. The samples were characterized by X-ray powder diffraction (XRD) pattern, scanning electron microscope analysis (SEM), Fourier transform infrared (FT-IR) spectroscopy and diffuse reflectance spectra (DRS). Powder XRD analysis and FT-IR spectroscopy confirmed the formation of ferrite spinel phase. The crystallite size was calculated to be 50-95 nm using Scherrer’s equation. The morphology and size of the synthesized nanoparticles have been observed by scanning electron microscopy. The particles were agglomerated without using surfactant. Using CTAB leads to the samples with layer shapes, and  using SDS leads to  the samples  with pyramidal shapes. The energy band gaps  calculated from UV–DRS absorption by using Kubelka-Munk equation were 1.68-1.77 eV, indicating that band gap of Cu ferrites becomes small and band gap of Ni ferrites becomes large in the presence of surfactant

Hexaaqua­nickel(II) tetra­aqua­bis­(μ-pyridine-2,6-dicarboxyl­ato)bis­(pyridine-2,6-dicarboxyl­ato)trinickelate(II) octa­hydrate

The title compound, [Ni(H2O)6][Ni3(C7H3NO4)4(H2O)4]·8H2O, was obtained by the reaction of nickel(II) nitrate hexa­hydrate with pyridine-2,6-dicarb­oxy­lic acid (pydcH2) and 1,10-phenanothroline (phen) in an aqueous solution. The latter ligand is not involved in formation of the title complex. There are three different NiII atoms in the asymmetric unit, two of which are located on inversion centers, and thus the [Ni(H2O)6]2+ cation and the trinuclear {[Ni(pydc)2]2-μ-Ni(H2O)4}2− anion are centrosymmetric. All NiII atoms exhibit an octa­hedral coordination geometry. Various inter­actions, including numerous O—H⋯O and C—H⋯O hydrogen bonds and C—O⋯π stacking of the pyridine and carboxyl­ate groups [3.570 (1), 3.758 (1) and 3.609 (1) Å], are observed in the crystal structure