Unusual behavior of the aqueous solutions of gemini bispyridinium surfactants: apparent and partial molar enthalpies of the dimethanesulfonates.

Apparent and partial molar enthalpies at 298 K of the aqueous solutions of cationic gemini surfactants 1,1'-didodecyl-2,2'-dimethylenebispyridinium dimethanesulfonate (12-Py(2)-2-(2)Py-12 MS); 1,1'-didodecyl-2,2'-trimethylenebispyridinium dimethanesulfonate (12-Py(2)-3-(2)Py-12 MS); 1,1'-didodecyl-2,2'-tetramethylenebispyridinium dimethanesulfonate (12-Py(2)-4-(2)Py-12 MS); 1,1'-didodecyl-2,2'-octamethylenebispyridinium dimethanesulfonate (12-Py(2)-8-(2)Py-12 MS); 1,1'-didodecyl-2,2'-dodecamethylenebispyridinium dimethanesulfonate (12-Py(2)-12-(2)Py-12 MS) were measured as a function of concentration and are here reported for the first time. They show a very peculiar behavior as a function of the spacer length, not allowing for the determination of a -CH 2- group contribution when this group is added to the spacer. The curve of the compound with a four-carbon-atom-long spacer lies between those of the compound with a spacer of 2 and 3 carbon atoms, instead of that below the latter, as expected.

Thermodynamics and biological properties of the aqueous solutions of new glucocationic surfactants.

Thermodynamic properties of aqueous solutions of newly synthesized compounds, namely, N-[2-(beta-D-glucopyranosyl)ethyl]-N,N-dimethyl-N-alkylammonium bromides with hydrophobic tails of 12 (C12DGCB) and 16 (C16DGCB) carbon atoms, determined as a function of concentration by means of direct methods, are reported here. Dilution enthalpies, densities, and sound velocities were measured at 298 K, allowing for the determination of apparent and partial molar enthalpies, volumes, and compressibilities. Changes in thermodynamic quantities upon micellization were derived using a pseudophase-transition approach.

Molecular modeling of binding between amidinobenzisothiazoles, with antidegenerative activity on cartilage, and matrix metalloproteinase-3.

The aim of the work was to investigate the mechanism of binding between human metalloproteinase-3 (MMP-3) and new compounds belonging to the benzisothiazolylamidines class. In vitro tests suggest that these molecules, endowed with antinflammatory and cartilage antidegenerative activity, could act as ligands toward MMP-3. In lack of experimental structural informations, we performed molecular docking simulations to probe the interactions of benzisothiazolylamidines with matrix metalloproteinase-3, using the docking package GOLD and the software HINT as a post-process scoring function.

Thermodynamics of aqueous solutions of dodecyldimethylethylammonium bromide.

The thermodynamic properties of the aqueous solutions of dodecyldimethylethylammonium bromide (DEDAB) were determined as a function of concentration by means of direct methods. Dilution enthalpies at 298 and 313 K, densities and sound velocities at 298 K were measured, allowing the determination of apparent and partial molar enthalpies, volumes, heat capacities and compressibilities. Changes in thermodynamic quantities upon micellization were derived using a pseudo-phase transition approach.

First evaluation of the thermodynamic properties for spheres to elongated micelles transition of some propanediyl-alpha,omega-bis(dimethylalkylammonium bromide) surfactants in aqueous solution.

The apparent and partial molar enthalpies, apparent molar volumes, and adiabatic compressibilities at 298 K of the aqueous solutions of the cationic gemini surfactants propanediyl-alpha,omega-bis(octyldimethylammonium bromide) (8-3-8) and propanediyl-alpha,omega-bis(dodecyldimethylammonium bromide) (12-3-12) have been measured as a function of concentration. The trends of the partial molar enthalpies versus concentration are the first well documented thermodynamic evidence of sphere to rod transition in the micellar phase, involving a detectable quantity of heat, and allow the determination of the change in enthalpy associated with this transition. The changes in enthalpies upon micellization and for the sphere to elongated micelles transition, DeltaH(s)(-->)(r), have been obtained from the experimental data by using a pseudo-phase transition approach: -1.

From ligand to complexes: inhibition of human immunodeficiency virus type 1 integrase by beta-diketo acid metal complexes.

beta-Diketo acid-containing compounds are a promising class of human immunodeficiency virus type 1 (HIV-1) integrase (IN) inhibitors. Starting from the hypothesis that these inhibitors are able to coordinate ions in solution before interacting on the active site, a series of potentiometric measurements have been performed to understand the coordination ability of the diketo acid pharmacophore toward the biologically relevant Mg(2+). Moreover, by using beta-diketo acid/ester as model ligands with a set of divalent metal ions (Mg, Mn, Ni, Co, Cu, and Zn), we obtained a series of complexes and tested them for anti-HIV-1 IN activity.

Biologically active bisquaternary ammonium chlorides: physico-chemical properties of long chain amphiphiles and their evaluation as non-viral vectors for gene delivery.

The biological properties of bisquaternary ammonium salts, which are derivatives of N,N-bisdimethyl-1,2-ethanediamine (bis-C(n)BEC), of general formula /C(n)H(2n+1)OOCCH2(CH3)2N(+)CH2CH2N(+)(CH3)2CH2COOC(n)H(2n+1)/2Cl-, were investigated (n=10, 12, 14). The interaction with model membrane was studied by differential scanning calorimetry experiments, and the apparent adiabatic molar compressibility of their solution as a function of concentration was obtained by sound velocity measurements. Their biological activities were assayed by Electrophoresis Mobility Shift, MTT proliferation, and transient transfection.