Structural, spectroscopic and theoretical studies of dimethylphenyl betaine complex with two molecules of 2,6-dichloro-4-nitro-phenol.

The 1:2 complex (1) of dimethylphenyl betaine (DMPB) with two molecules of 2,6-dichloro-4-nitro-phenol (DCNP) was prepared and characterized by X-ray diffraction, B3LYP/6-311++G(d,p) and B3LYP-D3/6-311++G(d,p)calculations, FTIR and NMR spectroscopies. The crystal is monoclinic, space group P21/c with Z=4. The protons at the oxygen atoms of phenols are bonded to each oxygen atoms of the DMPB carboxylate group by two nonequivalent H-bonds with the OH⋯O distances of 2.473(5) and 2.688(4)Å. Both H-bonds in the optimized structures 2 (in vacuum), 3 (in DMSO solution) and dispersion-correlated functional (D3) 4 (in vacuum) are comparable and are slightly shorter than O(6)H(O6)⋯O(2) in the crystal. The FTIR spectrum of 1 shows a broad absorption in the 3400-2000cm(-1) region corresponding to a longer hydrogen bond and a broad absorption in the 1800-500cm(-1) region caused by the shorter H-bond. The relations between the experimental (13)C and (1)H chemical shifts (δexp) of the investigated compound 1 in DMSO solution and GIAO/B3LYP/6-311++G(d,p) magnetic isotropic shielding constants (σcalc) obtained by using the screening solvation model (COSMO) for 3 are linear and reproduce well the experimental chemical shifts described by the equation: δexp=a+b σcalc.

Spectroscopic, structural and theoretical investigation of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate.

The structure of bis(4-trimethylammoniumbenzoate) hydroiodide hydrate 1 has been studied by X-ray diffraction, B3LYP/6-311G(d,p) calculations, FTIR, Raman and NMR spectroscopic techniques. The crystal is polar in monoclinic space group Cc. Two 4-trimethylammoniumbenzoate moieties are joined by a short and asymmetric hydrogen bond of 2.45(2) Å. Water molecules are gradually released from the structure, causing shifts in the position of iodine anions, which induces their disorder. The water molecule interacts with 4-trimethylammoniumbenzoate moiety and iodide anion via two O(3)-H(1)⋯O(1) and O(3)-H(2)⋯I(1) hydrogen bonds of lengths 2.70(3) and 3.51(1) Å. Hydrogen bonds in theoretically predicted structures of 2 and 3 (in vacuum), and 4, 5 (in DMSO) optimized by the B3LYP/6-311G(d,p) approach are slightly longer than in crystal 1. The FTIR spectrum of 1 shows a broad and intense absorption in the 1500-400 cm(-1) region, typical of short hydrogen bonds assigned to the νas(OHO)+γ(OHO) vibrations. The correlations between the experimental (13)C and (1)H chemical shifts (δexp) of the investigated compound in DMSO and the GIAO/B3LYP/6-311G(d,p) magnetic isotropic shielding constants (σcalc) calculated by using the screening solvation model (COSMO) are linear, δexp=a+b σcalc, and they well reproduce the experimental chemical shifts.

Synthesis and antimicrobial activities of some quaternary morpholinium chlorides.

The synthesis and antimicrobial activity of 31 morpholinium chlorides, divided into five series depending on the substituents attached to the nitrogen atom, N-carboxyalkyl-morpholinium chlorides (1a-e), N-carbalkoxymethyl-N-methyl-morpholinium chlorides (2a-f), N-carbethoxymethyl-N-alkyl-morpholinium chlorides (3a-g), N-carbalkoxymethyl-N-dodecyl-morpholinium chlorides (4a-f) and N-carboxymethyl-N-alkyl-morpholinium chlorides (5a-g) is reported. The compounds investigated were tested for antimicrobial activity against Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Candida albicans and Trichophyton menthagrophytes. The most active are compounds with a long N-alkyl group and with the substituent CH2COOC(n)H(2n-1) (n = 8-16).

Conformational richness and multiple Z' in salt co-crystal of N-methylpiperidine betaine with N-methylpiperidine betaine hexafluorosilicate.

The co-crystal structure of N-methylpiperidine betaine with N-methylpiperidine betaine hexafluorosilicate represents an unusual case of a salt co-crystal with a high Z' value (3), unexpected conformational variability, and with nearly 50% of its contents disordered. The betaine units from the salt and co-crystal formers are paired into several homoconjugated dimers via very short, linear O(-)...H(+)...O(-) bridges. These hydrogen bonds are the dominating interactions in the co-crystal structure, in variance with the simple hexafluorosilicate salt, which has a structure governed by COOH...F hydrogen bonds. The SiF(2-)(6) anion in the co-crystal structure has only C-H...F interactions with the betaine units. The zwitterion:cation:anion stoichiometry is 3:3:1.5. Some of the betaine units display disorder, but each case is different. One of the SiF(2-)(6) anions is ordered while possessing exact crystallographic symmetry. The other one is disordered in a general position. In addition, there are three water molecules in the crystal structure. One is fully ordered, one has an H atom disordered in two positions and the third one occupies two alternative positions with unequal populations.

Antimicrobial activity of N-alkoxycarbonylmethyl-N-alkyl-piperidinium chlorides.

The aim of the study was to assay antibacterial and antifungal activity of newly synthesised N-alkoxycarbonylmethyl-N-alkyl-piperidinium chlorides. The compounds tested were found to inhibit the growth of some Gram-negative bacteria, Gram-positive strains and some representatives of yeast-type Candida. From microbiological experiments two of the compounds tested, N-dodecyloxycarbonylmethyl-N-methyl-piperidinium chloride (3) and N-dodecyl-N-ethoxycarbonylmethyl-piperidinium chloride (6), emerged as more active than the other compounds. Since the resistance of biofilms to biocides should be noted during the design and testing of new antimicrobial agents therefore, we have analysed antibacterial properties of the most active compounds towards biofilms. Our study focused on strains of Pseudomonas aeruginosa and Staphylococcus aureus that served as main model organisms for the biofilm studies.