Catenated and spirocyclic polychalcogenides from potassium carbonate and elemental chalcogens.

The reaction of potassium carbonate with elemental sulfur or selenium in acetone in the presence of [PPN]Cl (PPN = (Ph3P)2N) produces catena-[S12]2-, the longest structurally characterised polysulfide dianion, or spiro-[Se11]2- as ion-separated [PPN]+ salts.

Magnetic cationic liposomal nanocarriers for the efficient drug delivery of a curcumin-based vanadium complex with anticancer potential.

In this work novel magnetic cationic liposomal nanoformulations were synthesized for the encapsulation of a crystallographically defined ternary V(IV)-curcumin-bipyridine (VCur) complex with proven bioactivity, as potential anticancer agents. The liposomal vesicles were produced via the thin film hydration method employing N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium (DOTAP) and egg phosphatidylcholine lipids and were magnetized through the addition of citric acid surface-modified monodispersed magnetite colloidal magnetic nanoparticles. The obtained nanoformulations were evaluated for their structural and textural properties and shown to have exceptional stability and enhanced solubility in physiological media, demonstrated by the entrapment efficiency and loading capacity results and the in vitro release studies of their cargo. Furthermore, the generated liposomal formulations preserved the superparamagnetic behavior of the employed magnetic core maintaining the physicochemical and morphological requirements for targeted drug delivery applications. The novel nanomaterials were further biologically evaluated for their DNA interaction potential and were found to act as intercalators. The findings suggest that the positively charged magnetic liposomal nanoformulations can generate increased concentration of their cargo at the DNA site, offering a further dimension in the importance of cationic liposomes as nanocarriers of hydrophobic anticancer metal ion complexes for the development of new multifunctional pharmaceutical nanomaterials with enhanced bioavailability and targeted antitumor activity.

A metal-organic framework via the reaction of benzoate with a cationic inorganic material.

Our research group previously reported a two-dimensional cationic inorganic material (BING-5, Pb(3)F(5)NO(3)) where nitrate resides in the interlamellar space and can be anion exchanged. Investigation of the possible exchange of nitrate for benzoate led to the discovery of a layered metal-organic framework, lead benzoate hydrate [Pb(C(6)H(5)CO(2))(2)(OH(2))]. The compound crystallizes as colourless plates in the monoclinic space group P2(1)/c. The two dimensional lead-oxygen layers contain bridging benzoate oxygen atoms, with bridging water molecules further supporting the layers. The benzoate molecules are positioned perpendicular to the layers and form a hydrophobic bilayer region. The material shows basic character when immersed in various solvents suggesting potential as a base catalyst.

Two related gadolinium aquo carbonate 2-D and 3-D structures and their thermal, spectroscopic, and paramagnetic properties.

We report two new extended inorganic materials based on gadolinium. The first, [Gd(CO(3))(2)H(2)O][NH(4)], consists of negatively charged 2-D sheets of gadolinium carbonate with one coordinated water molecule and an ammonium cation between the layers. The coordinated water and one carbonate extend into the interlayer space, connecting the layers via an extensive hydrogen bonding network which includes the ammonium ions. The second, a closely related yet more condensed framework structure, [Gd(2)(CO(3))(3)NH(3)H(2)O], is formed at a higher hydrothermal temperature and was characterized by single crystal X-ray diffraction data collected at a synchrotron. This second structure contains layers that are isostructural to the first, bridged together by carbonate, and coordinated by water and ammonia. The properties of these materials were studied by thermogravimetric analysis-mass spectrometry, photoluminescence, electron paramagnetic resonance, and Raman and infrared spectroscopy. The 2-D [Gd(CO(3))(2)H(2)O][NH(4)] is stable to about 175 degrees C, though water and ammonium loss continues through the entire thermogravimetric analysis trace. The 3-D material remains intact until about 325 degrees C. Both structures exhibit broad luminescence bands in the near-ultraviolet region centered at 354 nm. Electron paramagnetic resonance and magnetic susceptibility show spin-spin coupling between adjacent gadolinium atoms in both structures and confirm that they are paramagnetic. These materials show interesting photoluminescent and paramagnetic properties that could possibly be exploited for chemical sensing or magnetic materials applications.

Antimony oxide hydroxide ethanedisulfonate: a cationic layered metal oxide for Lewis acid applications.

We have discovered a rare example of a cationically charged inorganic material. The layered structure is an example outside the extensively studied isostructural set of anionic clays/layered double hydroxides and our previously reported lead fluoride nitrate. For the present compound, the antimony oxide hydroxide layers are positively charged and are templated by anionic alkylenedisulfonate. The organic molecules are only bonded electrostatically to the layers with sulfonate oxygen to antimony distances beyond the covalent range. The material catalyzes a ketal formation reaction as a Lewis acid without the need for drying the solvent before the reaction or a nonaqueous medium such as toluene. The catalyst is heterogeneous and is completely recovered after the catalysis for reapplication.