Socio-demographic and clinical characteristics of SARS-CoV-2-positive psychiatric in-patients: A case-control study in the psychiatric wards of a Great Metropolitan Hospital in Milan.

During the first Covid-19 outbreak, the Niguarda Hospital of Milan featured two Psychiatry wards, one for SARS-CoV-2 positive patient and one for patients requiring hospitalization and negative for SARS-CoV-2. The two groups of patients were compared and were similar in distribution of psychiatric diagnosis, duration of illness and previous hospitalizations. SARS-CoV-2 positive participants had a lower severity of symptoms both at admission and discharge, a lower frequency of psychotic symptoms and substance intoxication at admission. These findings suggest that patients admitted to the COVID ward were hospitalized not only for their mental health condition but also because of the infection.

Fluorescence Quenching by Redox Molecular Pumping.

Artificial molecular pumps (AMPs), inspired by the active cellular transport exhibited in biological systems, enable cargoes to undergo unidirectional motion, courtesy of molecular ratchet mechanisms in the presence of energy sources. Significant progress has been achieved, using alternatively radical interactions and Coulombic repulsive forces to create working AMPs. In an attempt to widen the range of these AMPs, we have explored the effect of molecular pumping on the photophysical properties of a collecting chain on a dumbbell incorporating a centrally located pyrene fluorophore and two terminal pumping cassettes. The AMP discussed here sequesters two tetracationic cyclophanes from the solution, generating a [3]rotaxane in which the fluorescence of the dumbbell is quenched. The research reported in this Article demonstrates that the use of pumping cassettes allows us to generate the [3]rotaxane in which the photophysical properties of fluorophores can be modified in a manner that cannot be achieved with a mixture of the dumbbell and ring components of the rotaxane on account of their weak binding in solution.

Exploiting fluorescent zinc(ii) and copper(ii) complexes for enantiomeric excess determination of hydroxycarboxylates.

Chiral hydroxycarboxylates are useful compounds in the syntheses of natural products, pharmaceutical intermediates, and drugs. Here, we report on Zn- and Cu-containing sensors that can distinguish between enantiomers of hydroxycarboxylates through the quenching or the enhancement of fluorescence. A Zn-based sensor-[ZnRRL]2+-is used in an assay to perform analyses of enantiomeric excess (% ee) of scalemic mixtures of α-hydroxycarboxylates and various drugs including the statin drug atorvastatin. This assay enables determination of mixtures of enantiomers across the range from 0 to 100% ee.

Cyclotris(paraquat-p-phenylenes).

Reported here is the synthesis, solid-state characterization, and redox properties of new triangular, threefold symmetric, viologen-containing macrocycles. Cyclotris(paraquat-p-phenylene) (CTPQT6+ ) and cyclotris(paraquat-p-1,4-dimethoxyphenylene) (MCTPQT6+ ) were prepared and their X-ray single-crystal (super)structures reveal intricate three-dimensional packing. MCTPQT6+ results in nanometer-sized channels, in contrast with its parent counterpart CTPQT6+ which crystallizes as a couple of polymorphs in the form of intercalated assemblies. In the solid state, MCTPQT3(.+) exhibits stacks between the 1,4-dimethoxyphenylene and bipyridinium radical cations, providing new opportunities for the manipulation and control of the recognition motif associated with viologen radical cations. These redox-active cyclophanes demonstrate that geometry-matching and weak intermolecular interactions are of paramount importance in dictating the formation of their intricate solid-state superstructures.

An indicator displacement assay recognizes enantiomers of chiral carboxylates.

Two chiral copper(ii)-based receptors-[CuRRL]2+ and [CuSSL]2+-in conjuction with the fluorescent indicator coumarin 343 were used to establish an enantioselective indicator displacement assay (eIDA) for the determination of the enantiomeric composition of chiral carboxylates such as ibuprofen, naproxen and atorvastatin.

Controlling Dual Molecular Pumps Electrochemically.

Artificial molecular machines can be operated using either physical or chemical inputs. Light-powered motors display clean and autonomous operations, whereas chemically driven machines generate waste products and are intermittent in their motions. Herein, we show that controlled changes in applied electrochemical potentials can drive the operation of artificial molecular pumps in a semi-autonomous manner-that is, without the need for consecutive additions of chemical fuel(s). The electroanalytical approach described in this Communication promotes the assembly of cyclobis(paraquat-p-phenylene) rings along a positively charged oligomeric chain, providing easy access to the formation of multiple mechanical bonds by means of a controlled supply of electricity.

Toward wearable sensors: optical sensor for detection of ammonium nitrate-based explosives, ANFO and ANNM.

Increasing security needs require compact and portable detection tools for the rapid and reliable identification of explosives used in improvised explosive devices (IEDs). We report of an easy-to-use optical sensor for both vapour-phase and solution-phase identification of explosive mixtures that uses a cross-reactive fluorimetric sensor array comprising chemically responsive fluorimetric indicators composed of aromatic aldehydes and polyethyleneimine. Ammonium nitrate-nitromethane (ANNM) was analyzed by paper microzone arrays and nanofiber sensor mats. Progress toward wearable sensors based on electrospun nanofiber mats is outlined.

Bowl-shaped Tröger's bases and their recognition properties.

The tris-Tröger's bases (TBs) are electron-rich fluorescent concave receptors due to the incorporation of naphthalene or triphenylene moieties (calix-1 and calix-2). The structures of the TBs were studied using SXRD to reveal the propensity to bind nitroaromatics. Titration with explosive-related nitro-compounds suggests that the TBs may be used for sensing explosives.

Fluorescent zinc and copper complexes for detection of adrafinil in paper-based microfluidic devices.

Recognition of electroneutral Lewis bases and anions in aqueous media is extremely difficult. We show that fluorescent coordinatively unsaturated metal complexes can recognize various Lewis bases while providing an easy-to-detect fluorescence response. This approach is applied to the detection of adrafinil, a banned performance-enhancing drug.

Small-Molecule Turn-On Fluorescent Probes for RDX.

New fluorescent probes have been tested for their ability to detect nitramine (RDX) and nitroaromatic (TNT) explosives. The probes display turn-on behavior upon exposure to RDX, while their fluorescence is dramatically reduced by the presence of TNT and other nitroaromatic compounds. The probes are applicable in qualitative assays that can distinguish between RDX and TNT as well as acidity and formaldehyde vapors.

Sensing of enantiomeric excess in chiral carboxylic acids.

Cinchona alkaloids (quinine, quinidine, cinchonine, cinchonidine) alkylated at N(1) with chloromethyl anthracene can serve as fluorescent sensors for chiral carboxylic acids. These cinchona ammonium salts are shown to bind chiral carboxylic acids while displaying an increase in fluorescence intensity that can be utilized in determination of enantiomeric excess (ee). Sensor arrays composed of four cinchona ammonium salts are used for quantitative analysis of ee in several non-steroidal anti-inflammatory drugs (NSAIDs), such as enantiomers of ibuprofen, ketoprofen, and naproxen.

Sensing of 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (2,4-DNT) in the solid state with photoluminescent Ru(II) and Ir(III) complexes.

A series of metal-organic chromophores containing Ru(II) or Ir(III) were studied for the luminometric detection of nitroaromatic compounds, including trinitrotoluene (TNT). These complexes display long-lived, intense photoluminescence in the visible region and are demonstrated to serve as luminescent sensors for nitroaromatics. The solution-based behavior of these photoluminescent molecules has been studied in detail in order to identify the mechanism responsible for metal-to-ligand charge-transfer (MLCT) excited state quenching upon addition of TNT and 2,4-dinitrotoluene (2,4-DNT). A combination of static and dynamic spectroscopic measurements unequivocally confirmed that the quenching was due to a photoinduced electron transfer (PET) process. Ultrafast transient absorption experiments confirmed the formation of the TNT radical anion product following excited state electron transfer from these metal complexes. Reported for the first time, photoluminescence quenching realized through ink-jet printing and solid-state titrations was used for the solid-state detection of TNT; achieving a limit-of-quantitation (LOQ) as low as 5.6 ng cm(-2). The combined effect of a long-lived excited state and an energetically favorable driving force for the PET process makes the Ru(II) and Ir(III) MLCT complexes discussed here particularly appealing for the detection of nitroaromatic volatiles and related high-energy compounds.

The interaction of fluoride with fluorogenic ureas: an ON1-OFF-ON2 response.

The anion binding tendencies of the two fluorogenic ureas L(1)H and L(2)H, containing the 2-anthracenyl and 1-pyrenyl moieties as signaling units, respectively, have been investigated in MeCN and DMSO by absorption, emission, and (1)H NMR spectroscopies. The formation of stable 1:1 receptor:anion H-bond complexes has been confirmed by structural studies on the crystalline [Bu4N][L(1)···Cl] and [Bu4N][L(2)H···CH3COO] salts. Complexation induces significant variations of the emission properties of L(1)H and L(2)H according to a multifaceted behavior, which depends upon the fluorogenic substituent, the solvent, and the basicity of the anion. Poorly basic anions (Cl(-), Br(-)) cause a red shift of the emission band(s). Carboxylates (CH3COO(-), C6H5COO(-)) induce fluorescence quenching due to the occurrence of an electron-transfer process taking place in the locally excited complex [*L-H···X](-). However, this excited complex may undergo an intracomplex proton transfer from one urea N-H fragment to the anion, to give the tautomeric excited complex [L···H-X](-)*, which emits at higher wavelength. F(-) displays a unique behavior: It forms with L(1)H a stable [L-H···F](-) complex which in the excited state undergoes intracomplex proton transfer, to give the poorly emissive excited tautomer [L···H-F](-)*. With L(2)H, on moderate addition of F(-), the 1:1 H-bond complex forms, and the blue fluorescence of pyrene is quenched. Large excess addition of F(-) promotes deprotonation of the ground-state complex, according to the equilibrium [L(2)H···F](-) + F(-) ⇆ [L(2)](-) + HF2(-). The deprotonated receptor [L(2)](-) is distinctly emissive (yellow fluorescence), which generates the fluorimetric response ON(1)-OFF-ON(2) of receptor L(2)H with respect to F(-).

Iptycene-based fluorescent sensors for nitroaromatics and TNT.

Small-molecule fluorescent sensors (1-5) for the recognition of nitroaromatic compounds, such as 2,4-dinitrotoluene and the explosive TNT, were obtained by using a three-step dehydrohalogenation cycloaddition protocol. The interaction of the receptors and nitroaromatics was studied both in solution and in the solid state by using fluorescence spectroscopy and X-ray crystallography, respectively. It is shown that the iptycene receptors 1-5 provide a cavity suitable for binding nitroaromatic compounds in an edge-to-face mode, rather than simple ring-stacking interactions. The results obtained inspired us to develop an inexpensive, reliable and robust sensor for vapour detection of explosives. Polymer nanofibres are particularly suitable for the production of such TNT sensors as they accelerate the mass exchange between the polymer and the vapours of TNT. Quenching of the sensors took place within 1 min compared to 10 min for a glass-slide assay. Hence, the sensor performance can be improved by optimising the matrix material and morphology without resynthesising the sensor moieties.

Moderate and advanced intramolecular proton transfer in urea-anion hydrogen-bonded complexes.

The study of the interactions of the three urea-based receptors AH, BH(+) and CH(2+) with a variety of anions, in MeCN, has made it possible to verify the current view that hydrogen bonding is frozen proton transfer from the donor (the urea N-H fragment in this case) to the acceptor (the anion X(-)). The poorly acidic, neutral receptor AH establishes two equivalent hydrogen bonds N-H···X(-), with all anions, including CH(3)COO(-) and F(-), in which moderate proton transfer from N-H to the anion takes place. The strongly acidic, dicationic receptor CH(2+) forms, with most anions, complexes in which two inequivalent hydrogen bonds are present: one involving moderate proton transfer (N-H···X(-)) and one in which advanced proton transfer has taken place, described as N(-)···H-X. The degree of proton advancement is directly related to the basic tendencies of the anion. The cationic receptor BH(+) of intermediate acidic properties only forms complexes with two inequivalent hydrogen bonds (moderate+advanced proton transfer) with CH(3)COO(-) and F(-), and complexes with two equivalent hydrogen bonds (moderate proton transfer) with all the other anions. Moreover, [B···HF] and [C···HF](+), on addition of a second F(-) ion, lose the bound HF molecule to give HF(2)(-). Release of CH(3)COOH, with the formation of [CH(3)COOH···CH(3)COO](-), also takes place with the [B···CH(3)COOH] complex in the presence of a large excess of anion.

Urea-, squaramide-, and sulfonamide-based anion receptors: a thermodynamic study.

In this work, we compare the anion-binding capabilities of receptors 1-5, characterized by similar structures, but possessing different hydrogen-bond-donor moieties (urea, squaramide, and sulfonamide). The presence of chromophoric substituents on the receptor's skeleton allowed the determination of association constants by performing UV/Vis titrations with the investigated anions on solutions of the receptors in pure acetonitrile. Additional quantitative studies of the anion-binding properties of receptors 1-5 were performed by isothermal titration calorimetry (ITC). The experimental results indicated that 1 and 2 formed 1:1 hydrogen-bonded complexes with most of the anions investigated. In the case of receptors 3-5, the formation of the 1:1 adduct was observed only with anions of low basicity (i.e., chloride, bromide, iodide, and hydrogen sulfate). With more basic anions (i.e., acetate and dihydrogen phosphate), both spectrophotometric and ITC titrations accounted for the deprotonation of the sulfonamide group, involving the formation of the conjugated base of the receptor.

Anion recognition by hydrogen bonding: urea-based receptors.

Since 1992 a variety of urea-based anion receptors have been synthesised, of varying complexity and sophistication. This critical review will focus on some distinctive aspects of anion recognition by urea derivatives, with a special reference to: (i) design and synthesis, (ii) methodologies for the investigation of the receptor-anion interaction in solution, (iii) the interpretation of the solution behaviour on the basis of the structural interplay between the receptor and the anion. It will be shown that the efficiency of urea as a receptor subunit depends on the presence of two proximate polarised N-H fragments, capable (i) of chelating a spherical anion or (ii) of donating two parallel H-bonds to the oxygen atoms of a carboxylate or of an inorganic oxoanion, a property which is shared with other diamides, e.g. squaramide. The wide use of urea in the design of neutral anion receptors seems to depends on the ease of its synthesis, in particular through the reaction of a primary amine group with an isocyanate, which allows the high-yield preparation of symmetrically and unsymmetrically substituted derivatives (83 references).

Octahedral copper(II) and tetrahedral copper(I) double-strand helicates: chiral self-recognition and redox behavior.

The racemic form of 5 ((RR)5 + (SS)5) gives dinuclear complexes of 2:2 stoichiometry both with Cu(II), acting as a bis-terdentate ligand, and with Cu(I), acting as a bis-bidentate ligand. Single crystal X-ray diffraction studies have shown that the Cu(II) complex exists as double-strand homochiral helicate molecules: P,P-[Cu(2)(II)((RR)5)(2)](4+) and M,M-[Cu(2)(II)((SS)5)(2)](4+); in which the two trans-1,2-cyclohexanediamine subunits have the same chirality for of the two strands. Each Cu(II) metal center is six-coordinated according to a cis-octahedral geometry and interacts with a NNO donor subunit of each strand. The Cu(I) complex, when crystallized from THF in the presence of (rac)5, gives a double-strand homochiral helicate complex and in the solid state forms a racemic mixture of the homochiral metal complexes M,M-[Cu(2)(I)((RR)5)(2)](2+) and P,P-[Cu(2)(I)((SS)5)(2)](2+). When crystallizing from a MeCN solution, Cu(I) and (rac)5 give rise to the heterochiral nonhelicate dimeric complex [Cu(2)(I)((RR)5)((SS)5)](2+), in which the two strands of the dimer have inverse configuration of the trans-1,2-cyclohexanediamine subunits and are assembled side-by-side. In both structural architectures, the Cu(I) centers are four-coordinated by two nitrogen atoms from each strand, according to a distorted tetrahedral geometry. In MeCN solution, the dinuclear Cu(II) complex disassembles to give the mononuclear species, which, on reduction at a platinum electrode in a cyclic voltammetry experiment, gives two Cu(I) mononuclear complexes that quickly assemble to give the dinuclear Cu(I) complex. This complex undergoes two consecutive one-electron oxidation processes, but the dinuclear Cu(II) species that forms decomposes in less than 1 s. On the contrary, the [Cu(2)(I)((rac)5)(2)](2+) complex is stable in MeCN solution and undergoes two one-electron oxidation processes to give a form of dinuclear Cu(II) complex that lasts in solution for more than 20 s.

Templated synthesis of copper(II) azacyclam complexes using urea as a locking fragment and their metal-enhanced binding tendencies towards anions.

Copper(II) azacyclam complexes 3(2+) and 4(2+) were obtained through a metal-templated procedure involving the pertinent open-chain tetramine, formaldehyde and a phenylurea derivative as a locking fragment. Both metal complexes can establish interactions with anions through the metal centre and the amide NH group. Equilibrium studies in DMSO by a spectrophotometric titration technique were carried out to assess the affinity of 3(2+) and 4(2+) towards anions. While the NH group of an amide model compound and the metal centre of the plain Cu(II)(azacyclam)(2+) complex do not interact at all with anions, 3(2+) and 4(2+) establish strong interactions with oxo anions, profiting from a pronounced cooperative effect. In particular, 1) they form stable 1:1 and 1:2 complexes with H(2)PO(4) (-) ions in a stepwise mode with both hydrogen-bonding and metal-ligand interactions, and 2) in the presence of CH(3)COO(-), they undergo deprotonation of the amido NH group and thus profit from axial coordination of the partially negatively charged carbonyl oxygen atom in a scorpionate binding mode.

Metal-controlled anion-binding tendencies of the thiourea unit of thiosemicarbazones.

The terdentate ligand 3 (LH, 2-formylpyridine 4-thiosemicarbazone) forms with FeII and NiII 2:1 complexes of octahedral geometry of formula [MII(LH)2]2+. X-ray diffraction studies have shown that in both complexes the thiourea moieties of the coordinated thiosemicarbazones are exposed to the outside and are prone to establish hydrogen-bonding bifurcate interactions with oxoanions. However, spectrophotometric studies in CHCl3 solution have shown that only the poorly basic NO3 - ion is able to form authentic hydrogen-bond complexes with thiourea subunits, whereas all the other investigated anions (CH3COO-, NO2 -, F-) induce deprotonation of the N-H fragment. The extreme enhancement of the thiourea acidity is based on the coordinative interaction of the sulphur atom with the metal, which stabilises the thiolate form, and it is much higher than that exerted by any other covalently linked electron-withdrawing substituent, for example, --NO2.