Designing Ionic Ir(III) Cyclometalated Complexes as Photocatalysts for Light Assisted ATRP of MMA. A Combined Experimental and Mechanistic Study

A new family of ionic Ir(III) cyclometalated complexes with general formula [Ir(CN)2(NN)][Br], was designed and prepared to be assessed as photocalysts for the visible light assisted ATRP polymerization of MMA. To this purpose, our design strategy involved both: i) the decoration of the cyclometalating (CN) and the ancillary (NN) ligands with various electron withdrawing and/or electron donor substituents and, ii) the use of Br- as the counter anion for these cationic Ir(III) species. After an extensive screening in which the [Ir(CN)2(NN)][Br]-type compounds were compared to the model neutral complex fac-[Ir(ppy)3], the "fully" amino-substituted ion pairs abbreviated as [10][Br] and [11][Br], exhibited the best photocatalytic performances under irradiation with CFL lamps. It is worth noting that the outcomes of transient absorption spectroscopy (TAS) experiments combined with theoretical DFT calculations, enlightened the role played by the Ir(III) complexes in the mechanism of the photoATRP process, and suggested the rationalization of the different performances that were highlighted by our Ir(III) catalyst in the visible light assisted photopolymerization of MMA.

Trapping an unprecedented octacoordinated iron(II) complex with neutral bis-tetrazolylpyridyl ligands and solvent molecules

Iron(II) can show a very rich coordination chemistry with concomitant modulation of its properties as promising functional materials. Metalation of the neutral tridentate nitrogen-donor mer-coordinating ligand 2,6-bis(2-(methyl)-2H-tetrazol-5-yl)pyridine (Me2btp) with Fe(ClO4)2·6H2O through accurate solvent polarity control enables the selective crystallization of [FeHS/LS(Me2btp)2](ClO4)2·MeCN·2.75H2O (2HS/LS·MeCN·2.75H2O) as red rods, where half of the iron(II) centres resides in the low spin (LS, S = 0) state and the other half is in the high spin (HS, S = 2) state. The red rods spontaneously convert into yellow crystals once removed from the mother liquor and exposed to air due to solvent rearrangement within the crystal packing; these new crystals can be assigned to [FeHS(Me2btp)2](ClO4)2·solvent (2HS·solvent) where all the iron(II) centres are now blocked in the HS state, as confirmed by magnetic measurements. The polarity of the crystallization solvent, together with the maintenance of the crystals within the mother liquor, are pivotal for the reactivity and interconversion of different species. Indeed, upon long standing in solution, 2HS/LS·MeCN·2.75H2O converts to another form of red crystals belonging to [FeLS(Me2btp)2][FeHS(Me2btp)(MeCN)2(H2O)](ClO4)4·MeCN (2LS·3HS·MeCN), as confirmed by single crystal X-ray diffraction data. In this co-crystal, the iron(II) in 2 resides in the LS state at all temperatures while the iron(II) in 3 is blocked in the HS state. Well-formed yellow crystals could be also isolated among the red crystals of 2HS/LS·MeCN·2.75H2O, and they could be identified as the unprecedented octacoordinated species [Fe(Me2btp)2(MeCN)(H2O)](ClO4)2·H2O (1·H2O) by single-crystal X-ray diffraction. These yellow crystals are stable in the air, but slowly convert into 2LS·3HS·MeCN if kept in the mother liquor for about one week. 1·H2O can be considered the trapped intermediate in the solid state during the conversion of [FeHS(Me2btp)2]2+ into [FeHS(Me2btp)(MeCN)2(H2O)]2+ in solution, where the two tridentate ligands in the starting species can unfold to accommodate coordinated MeCN and H2O molecules, as confirmed by theoretical calculations, and eventually one of the two Me2btp is completely replaced by the solvent.

Prenatal Clinical Findings in RASA1-Related Capillary Malformation-Arteriovenous Malformation Syndrome

Pathogenic variants in RASA1 are typically associated with a clinical condition called “capillary malformation-arteriovenous malformation” (CM-AVM) syndrome, an autosomal dominant genetic disease characterized by a broad phenotypic variability, even within families. In CM-AVM syndrome, multifocal capillary and arteriovenous malformations are mainly localized in the central nervous system, spine and skin. Although CM-AVM syndrome has been widely described in the literature, only 21 cases with prenatal onset of clinical features have been reported thus far. Here, we report four pediatric cases of molecularly confirmed CM-AVM syndrome which manifested during the prenatal period. Polyhydramnios, non-immune hydrops fetalis and chylothorax are only a few possible aspects of this condition, but a correct interpretation of these prenatal signs is essential due to the possible fatal consequences of unrecognized encephalic and thoracoabdominal deep vascular malformations in newborns and in family members carrying the same RASA1 variant.

Synthesis and Stereodynamic and Emission Properties of Dissymmetric Bis-Aryl Carbazole Boranes and Identification of a CPL-Active B-C Atropisomeric Compound

We synthesized bis-aryl carbazole borane derivatives having emissive properties and axial chirality. The resolution of a thermally stable atropisomeric pair (compound 1b), due to a B-C chiral axis, was achieved by chiral stationary-phase high-performance liquid chromatography (CSP-HPLC). Complete photophysical properties of all compounds were measured and simulated by time-dependent density functional theory (TD-DFT) calculations of the complete fluorescence cycle, and circularly polarized luminescence spectra were obtained for the atropisomers of compound 1b, whose absolute configuration was derived using a TD-DFT simulation of the electronic circular dichroism (ECD) spectra.

Clinical application of lung ultrasound score on COVID-19 setting: a regional experience in Southern Italy

OBJECTIVE

We aimed to assess the correlation between LUS Soldati proposed score and clinical presentation, course of disease and the possible need of ventilation support/intensive care.

PATIENTS AND METHODS

All consecutive patients with laboratory confirmed SARS-CoV-2 infection and hospitalized in two COVID Centers were enrolled. All patients performed blood gas analysis and lung ultrasound (LUS) at admission. The LUS acquisition was based on standard sequence of 14 peculiar anatomic landmarks with a score between 0-3 based on impairment of LUS picture. Total score was computed with their sum with a total score ranging 0 to 42, according to Soldati LUS score. We evaluated the course of hospitalization until either discharge or death, the ventilatory support and the transition in intensive care if needed.

RESULTS

One hundred and fifty-six patients were included in the final analysis. Most of patients presented moderate-to-severe respiratory failure (FiO2 <20%, PaO2 <60 mmHg) and consequent recommendation to invasive mechanic ventilation (CPAP/NIV/OTI). The median ultrasound thoracic score was 28 (IQR 18-36) and most of patients could be ascertained either in a score 2 (40%) or score 3 pictures (24.4%). The bivariate correlation analysis displayed statistically significant and high positive correlations between the LUS score and the following parameters: ventilation (rho=0.481, p<0.001), lactates (rho=0.464, p<0.001), dyspnea (rho=0.398, p=0.001) mortality (rho=0.410, p=0.001). Conversely, P/F (rho= -0.663, p<0.001), pH (rho = -0.363, p=0.003) and pO2 (rho = -0.400 p=0.001) displayed significant negative correlations.

CONCLUSIONS

LUS score improve the workflow and provide an optimal management both in early diagnosis and prognosis of COVID-19 related lung pathology.

Highly twisted carbazole-borane derivatives: B–N stereodynamic analysis and consequences on their emission properties

The manuscript describes the stereodynamic features of amino bis-mesityl-boranes bearing carbazole and benzocarbazole as donor heterocycles, and how they influence the photophysical properties.

New examples of Ru(II)-tetrazolato complexes as thiocyanate-free sensitizers for dye-sensitized solar cells

A set of three new Ru(ii) polypyridyl complexes decorated with 5-aryl tetrazolato ligands (R-CN4)-, (D series, namely D1, D3 and D4), is presented herein. Whereas complex D1 represents the pyrazinyl tetrazolato analogue of a previously reported Ru(ii) complex (D2) with the general formula cis-[(dcbpy)2Ru(N^N)]+, in which dcbpy is 2,2'-bipyridine-4,4'-dicarboxylic acid and N^N is the chelating 2-pyridyl tetrazolato anion, the design of the unprecedented Ru(ii) species D3 and D4 relied upon a completely different architecture. More specifically, the molecular structure of thiocyanate-based species cis-[(dcbpy)2Ru(NCS)2], that is typically found in benchmark Ru(ii) dyes for dye sensitized solar cell (DSSCs), was modified with the replacement of two of the -NCS ligands in favour of the introduction of 5-aryl tetrazolato anions, such as the deprotonated form of 5-(4-bromophenyl)-1H-tetrazole, for complex D3 and 5-(4-cyanophenyl)-1H-tetrazole in the case of complex D4. To streamline the behavior of the D series of Ru(ii) complexes as photosensitizers for DSSCs, an in-depth analysis of the excited state properties of D1, D3 and D4 was performed through TDDFT calculations and TDAS (nanosecond transient difference absorption spectroscopy). The obtained results highlight a trend that was confirmed once D1, D3 and D4 were tested as photosensitizers for DSSC under different conditions. Along the series of the Ru(ii) complexes, the neutrally charged species D3 and D4 displayed the best photovoltaic performances.

Heteromultimetallic compounds based on polyfunctional carboxylate linkers

Polyfunctional linkers bearing carboxylate, bipyridine and alkyne functionalities allow the stepwise construction of multimetallic assemblies incorporating redox and photophysical properties.

Luminescent protein staining with Re(i) tetrazolato complexes

Re(i) tricarbonyl diiimine complexes for the first time exploited as luminescent staining agents for SDS-PAGE.

Encapsulation of cationic iridium(iii) tetrazole complexes into a silica matrix: synthesis, characterization and optical properties

We designed a multi-scale process, and obtained luminescent powders with preserved optical properties from molecular scale to microscale.

Methylation of Ir(iii)-tetrazolato complexes: an effective route to modulate the emission outputs and to switch to antimicrobial properties

Two neutral cyclometalated Ir(iii)-tetrazolato complexes that differ by variations of the substituents on either the phenylpyridine or the tetrazolate ligand have been converted into the corresponding methylated and cationic analogues. NMR (¹H and ¹³C) characterization of the Ir(iii) complexes provided the results in agreement with the chemo- and regioselective character of methylation at the N-3 position of the Ir(iii)-coordinated tetrazolato ring. This evidence was further corroborated by the analysis of the molecular structures of the cationic complexes obtained by X-ray diffraction. In view of the photophysical properties, the addition of a methyl moiety to neutral Ir(iii) tetrazolates, which behave as sky-blue or orange phosphors, caused a systematic red shift of their phosphorescence output. The transformation of neutral Ir(iii) tetrazolates into cationic Ir(iii)-tetrazole complexes was screened for any eventual antimicrobial activity in vitro against Gram negative (E. coli) and Gram positive (D. radiodurans) microorganisms. While both kinds of complexes were not active against E. coli, the conversion of the neutral Ir(iii) tetrazolates into the corresponding methylated and cationic Ir(iii)tetrazole derivatives determined the turn-on of a good to excellent antimicrobial activity toward Gram positive Deinococcus radiodurans, a non-pathogenic bacterium that is listed as one of the toughest microorganisms in light of its outstanding resistance to radiation and oxidative stress.

The stepwise generation of multimetallic complexes based on a vinylbipyridine linkage and their photophysical properties

The versatile rhenium complex [ReCl(CO)₃(bpyC[triple bond, length as m-dash]CH)] (HC[triple bond, length as m-dash]Cbpy = 5-ethynyl-2,2'-bipyridine) is used to generate a series of bimetallic complexes through the hydrometallation of [MHCl(CO)(BTD)(PPh₃)₂] (M = Ru, Os; BTD = 2,1,3-benzothiadiazole). The ruthenium complex [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}Cl(BTD)(CO)(PPh₃)₂] was characterised structurally. Ligand exchange reactions with bifunctional linkers bearing oxygen and sulfur donors provide access to tetra- and pentametallic complexes such as [{M{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}(CO)(PPh₃)₂}₂(S₂CNC₄H₈NCS₂)] and Fe[C₅H₄CO₂M{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}(CO)(PPh₃)₂]₂. The effect of the group 8 metal on the photophysical properties of the rhenium centre was investigated using the complexes [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}Cl(BTD)(CO)(PPh₃)₂] and [M{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}{S₂P(OEt)₂}(CO)(PPh₃)₂] (M = Ru, Os). This revealed the quenching of the rhenium-based emission in favour of weak radiative processes based on the Ru and Os centres. The potential for exploiting this effect is illustrated by the reaction of [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}Cl(CO)(BTD)(PPh₃)₂] with carbon monoxide, which results in a 5-fold fluorescence enhancement in the dicarbonyl product, [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)₃}Cl(CO)₂(PPh₃)₂], as the quenching effect is disrupted.

The burden of early-onset sepsis in Emilia-Romagna (Italy): a 4-year, population-based study

OBJECTIVE

To provide the first Italian data on pathogens causing early-onset sepsis (EOS) and their antimicrobial susceptibility, after the successfully prevention of Group B streptococcus (GBS) EOS.

METHODS

Retrospective area-based cohort study from Emilia-Romagna (Italy). Cases of EOS registered (from 2009 to 2012) in all gestational age neonates were reviewed.

RESULTS

Live births (LB) numbered 146 682. Ninety neonates had EOS and 12 died (incidence rates of 0.61 and 0.08/1000 LB, respectively). EOS and mortality were the highest among neonates with a birth weight <1000 g (20.37/1000 LB and 8.49/1000 LB, respectively). The most common pathogens were GBS (n = 27, 0.18/1000 LB) and Escherichia coli (n = 19, 0.13/1000 LB). Most infants affected by E. coli EOS were born preterm (n = 13), had complications (n = 4) or died (n = 7). Among 90 isolates tested, only 3 were resistant to both first line empirical antibiotics. Multivariate logistic regression analysis showed that low gestational age, caesarean section and low platelet count at presentation were significantly associated with death or brain lesions (area under ROC curve = 0.939, H-L = 0.944, sensitivity 76.0%, specificity 90.7%).

CONCLUSIONS

GBS slightly exceeds E. coli as a cause of EOS. However, E. coli is the prominent cause of death, complications and in most cases affects preterm neonates. Empirical antimicrobial therapy of EOS seems appropriate.

Fully Ir(iii) tetrazolate soft salts: the road to white-emitting ion pairs

The first examples of anionic Ir(iii) bis-tetrazolate complexes and their combination with a cationic Ir(iii)tetrazole derivative forming “fully tetrazolate” Ir(iii) based soft salts as O₂-sensitive white emitters are described herein.

Negatively charged Ir(iii) cyclometalated complexes containing a chelating bis-tetrazolato ligand: synthesis, photophysics and the study of reactivity with electrophiles

The synthesis, the reactivity toward electrophiles and use for Ir(iii) based soft salts of new anionic Ir(iii) complexes containing a bis-tetrazolato ligand are described herein.

Methylated Re(i) tetrazolato complexes: photophysical properties and Light Emitting Devices

Methylated Re(i) tetrazolato complexes are suitable as phosphors for Light Emitting Devices.

Targeting divalent metal cations with Re(i) tetrazolato complexes

The design, preparation and characterization of four new Re(i) tetrazolato complexes together with the study of their luminescent sensing abilities toward Zn(ii), Cd(ii) and Cu(ii) are described herein.

Severe acquired cytomegalovirus infection in a full-term, formula-fed infant: case report

BACKGROUND

Cases of cytomegalovirus colitis are exceptionally reported in immuno-competent infant. The pathogenesis is uncertain but breast-feeding is considered as a main source of postnatal infection.

CASE PRESENTATION

Here we report a full-term, formula-fed infant who developed a severe cytomegalovirus anaemia and colitis when aged 2 months.

CONCLUSION

Even if the molecular identity between the cytomegalovirus-isolate of the infant and the maternal virus could not be demonstrated, we confirmed through laboratory investigation that cytomegalovirus infection was acquired postnatally. However, the source of cytomegalovirus infection remained unclear. Alternative modes of cytomegalovirus transmission are discussed.

[Serum bile acids in the newborn: our experience]

The study of bile acids in the newborn permits to the AA. to point out that the beginning of the feeding does not influence the "physiologic cholestasis" of the first days of life. Neonatal cholestasis is the expression of the immaturity of bile acids synthesis and hepatic and intestinal carriage, which is not correlated with the maternal conditions. Furthermore, the AA. discuss about the analogy between cholestasis and "physiologic hyperbilirubinemia", from which it differs for the longer time. In fact, the maturation of the enterohepatic circle occurs very slowly under possible dietetic factors influences.

[Thrombophlebitis of the cavernous sinus and inappropriate ADH secretion syndrome]

The septic thrombosis of the cavernous sinus is a rare and serious disease which still occurs occasionally. The physician should be aware of this fact when treating infections of the nasal orbital areas. A case is presented in whom the septic thrombosis of the cavernous sinus is associated with the syndrome of inappropriate secretion of antidiuretic hormone.