Copper and Zinc Metal–Organic Frameworks with Bipyrazole Linkers Display Strong Antibacterial Activity against Both Gram+ and Gram− Bacterial Strains

: Here, we report a new synthetic protocol based on microwave-assisted synthesis (MAS) for the preparation of higher yields of zinc and copper in MOFs based on different bis(pyrazolyl)-tagged ligands ([M(BPZ)]n where M = Zn(II), Cu(II), H2BPZ = 4,4'-bipyrazole, [M(BPZ-NH2)]n where M = Zn(II), Cu(II); H2BPZ-NH2 = 3-amino-4,4'-bipyrazole, and [Mx(Me4BPZPh)] where M = Zn(II), x = 1; Cu(II), x = 2; H2Me4BPZPh = bis-4'-(3',5'-dimethyl)-pyrazolylbenzene) and, for the first time, a detailed study of their antibacterial activity, tested against Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, as representative agents of infections. The results show that all MOFs exert a broad-spectrum activity and strong efficiency in bacterial growth inhibition, with a mechanism of action based on the surface contact of MOF particles with bacterial cells through the so-called "chelation effect" and reactive oxygen species (ROS) generation, without a significant release of Zn(II) and Cu(II) ions. In addition, morphological changes were elucidated by using a scanning electron microscope (SEM) and bacterial cell damage was further confirmed by a confocal laser scanning microscopy (CLSM) test

Ab initio investigation of the affinity of novel bipyrazolate-based MOFs towards H2and CO2

Two recently synthesized Zn and Cu tetramethyl-bipyrazole-based metal organic frameworks have been characterized and compared as regards their structural and electronic properties and their reactivity towards hydrogen and CO2 molecules. Ab initio calculations have been performed on periodic models with the B3LYP hybrid and an empirical long-range dispersion correction. Interactions with the probe molecules in the two structures are almost iso-energetic and in all cases the physisorption becomes reversible as the temperature increases. Topological analysis of the electron density has been used to fully characterize the chemical bonding. On the basis of our study, it can be inferred that the experimentally observed larger adsorption capacity of the Cu framework is not ascribable to the strong interaction of the guest molecules with an exposed metal ion but to the higher number of adsorption sites and to the larger void volume

Steric and Electronic Effects Responsible for N, O- or N, N-Chelating Coordination of Pyrazolones Containing a Pyridine Ring in Ruthenium Arene Systems

Structural and electronic factors are crucial to rationalize the different N,O or N,N chelating coordination of pyrazolones containing a pyridine ring. The reactivity of proligand 3-phenyl-1-(pyridin-2-yl)-5-pyrazolone (HLpy,ph) with the (arene)Ru(II) fragment was explored. Neutral and ionic (arene)Ru(II) complexes were obtained and fully characterized, also by X-ray diffraction, revealing the ligand to coordinate in an unusual N,O-chelating fashion. Other ruthenium complexes were also synthesized with 3-methyl-1-(pyridin-2-yl)-5-pyrazolone (HLpy,me) and 3-methyl-1-(pyridin-2-yl)-4-trifluoroacetyl-5-pyrazolone (HQpy,CF3). In these complexes the ligands adopt the preferred N,N-chelating mode. Ligands and complexes were theoretically analyzed by density functional theory (DFT). The most stable tautomer of HLpy,phmatched well with the experimental behavior of this proligand and the structures of Ru-complexes were well described by calculations. The thermodynamic stability of the N,O- and N,N-coordination modes was analyzed and a proposal for the achievement of the N,O-coordination mode in complexes 1-4 was proposed. Cytotoxicity tests were performed against human ovarian carcinoma (A2780 and Cisplatin-resistant A2780cis) and nontumorigenic human embryonic kidney (HEK293T) cell lines, showing the free ligands to be more cytotoxic that the ensuing (arene)Ru(II) complexes

Chemical behavior and in vitro activity of mixed phosphine gold(I)compounds on melanoma cell lines.

7partially_openCARUSO F; PETTINARI C; PADUANO F; VILLA R; MARCHETTI F; E. MONTI; ROSSI MCaruso, F; Pettinari, C; Paduano, F; Villa, R; Marchetti, F; Monti, ELENA CATERINA; Rossi, M

A New Quantitative Classification of the Extrahepatic Biliary Tract Related to Cystic Duct Implantation

Background: Knowledge regarding biliary anatomy and its variations, including the cystic duct (CD), is important in the pre-surgical setting and for predicting biliary diseases. However, no large series has focused on CD evaluation using a quantitative analysis. The primary aim of this prospective study was to create a ‘taxonomic’ classification of CD anatomy in a large cohort of subjects who underwent magnetic resonance cholangiopancreatography (MRCP). The secondary aim was to evaluate the correlations between extrahepatic bile duct (EHBD) variants and biliary diseases. Methods: We enrolled patients who underwent MRCP for different clinical indications from January 2017 to May 2019. Demographical, anatomical and clinical data were evaluated using statistical analyses, as appropriate. The anatomical assessment of EHBD was performed using the standard classification for CD in low, medium, and high insertions, and the lengths of CD to the duodenal papilla (DP), and EHBD was determined to conduct a new quantitative analysis. Results: The final study population comprised 1004 subjects. A new classification for EHBD as per the percentile distribution of the ratio CDDP/EHBD was designed, and the following categories were obtained: type 1 (below the 25th percentile) for CDDP/EHBD ratio ≤ 50%; type 2 (25th to 75th percentile) for CDDP/EHBD ratio 51–75% and type 3 (above the 75th percentiles) for CDDP/EHBD ratio > 75%. Type 1 of the new classification of CD implantation was significantly superior in terms of the detection of low, medial and intra-pancreatic CD that was significantly correlated with a high risk of choledochal lithiasis in comparison with the standard classification (P < 0.001). Conclusions: The new classification of CD implantation enables identification of the vast majority of intra-pancreatic CDs that are correlated with a high risk of choledochal lithiasis in a single category (type 1) that is easy to identify using imaging

Raman scattering reveals strong LO-phonon-hole-plasmon coupling in nominally undoped GaAsBi: optical determination of carrier concentration

We report room-temperature Raman scattering studies of nominally undoped (100) GaAs1−xBix epitaxial layers exhibiting Biinduced (p-type) longitudinal-optical-plasmon coupled (LOPC) modes for 0.018≤x≤0.048. Redshifts in the GaAs-like optical modes due to alloying are evaluated and are paralleled by strong damping of the LOPC. The relative integrated Raman intensities of LO(Γ) and LOPC ALO/ALOPC are characteristic of heavily doped p-GaAs, with a remarkable near total screening of the LO(Γ) phonon (ALO/ALOPC →0) for larger Bi concentrations. A method of spectral analysis is set out which yields estimates of hole concentrations in excess of 5 × 1017 cm−3 and correlates with the Bi molar fraction. These findings are in general agreement with recent electrical transport measurements performed on the alloy, and while the absolute size of the hole concentrations differ, likely origins for the discrepancy are discussed. We conclude that the damped LO-phonon-hole-plasmon coupling phenomena plays a dominant role in Raman scattering from unpassivated nominally undoped GaAsBi