Beyond transition block metals: exploring the reactivity of phosphine PTA and its oxide [PTA(O)] towards gallium(iii).

The water-soluble cage-like phosphine PTA (1,3,5-triaza-7-phosphaadamantane) and its phosphine oxide derivative [PTA(O)] (1,3,5-triaza-7-phosphaadamantane-7-oxide) were used to explore their reactivity towards two gallium(iii)-halide precursors, namely GaCl and GaI, for the first time. By using various reaction conditions, a series of -mono-protonated phosphine salts with [GaCl] or [I] as counterions were obtained in all cases, while the formation of coordinated Ga-PTA and Ga-[PTA(O)] complexes was not observed. All compounds were characterized in solution using multinuclear NMR spectroscopy (H, C{H}, P{H} and Ga) and in the solid state using FT-IR spectroscopy and X-ray crystal diffraction.

The Role of Inverted Ligand Field in the Electronic Structure and Reactivity of Octahedral Formal Platinum (IV) Complexes.

Platinum complexes are ubiquitous in chemistry and largely used as catalysts or as precursors in drug chemistry, thus a deep knowledge of their electronic properties may help in planning new synthetic strategies or exploring new potential applications. Herein, the electronic structure of many octahedral platinum complexes is drastically revised especially when they feature electronegative elements such as halogens and chalcogens. The investigation revealed that in most cases the five d platinum orbitals are invariably full, thus the empty antibonding orbitals, usually localized on the metal, are mainly centered on the ligands, suggesting a questionable assignment of formal oxidation state IV.

Essential Oils for the Conservation of Paper Items.

Archival documents and artworks stored in libraries frequently undergo degradative processes promoted by the so-called "biodeteriogens" that inhabit these places. A renewed interest in plant-derived products has arisen in those research groups focusing on cultural heritage preservation and looking for new and safe disinfection techniques. In this view, essential oils (EOs) and their volatile organic constituents are very appealing thanks to their versatility of action.

Halogen-Bonding-Mediated Radical Reactions: The Unexpected Behavior of Piperazine-Based Dithiooxamide Ligands in the Presence of Diiodine.

,'-Dialkylpiperazine-2,3-dithiones (Rpipdt) were recognized as a class of hexa-atomic cyclic dithiooxamide ligands with peculiar charge-transfer donor properties toward soft electron-acceptors such as noble metal cations and diiodine. The latter interaction is nowadays better described as halogen bonding. In the reaction with diiodine, Rpipdt unexpectedly provides the corresponding triiodide salts, differently from the other dithiooxamides, which instead typically achieve ligand·nI halogen-bonded adducts.

Plant Sampling for Production of Essential Oil and Evaluation of Its Antimicrobial Activity In Vitro.

Essential oils (EOs) and oleoresins are complex mixtures mainly made up of terpenes, synthesized by a wide variety of plants. Individual terpenes may show broad-spectrum activity against different plant pathogens, and their combination into EO and oleoresin mixtures enhances plant chemical defense. The interest in EOs has significantly increased due to the trend of using natural products as herbicides, insecticidal and antimicrobial agents.

Inverted Ligand Field in a Pentanuclear Bow Tie Au/Fe Carbonyl Cluster.

Gold chemistry has experienced in the last decades exponential attention for a wide spectrum of chemical applications, but the +3 oxidation state, traditionally assigned to gold, remains somewhat questionable. Herein, we present a detailed analysis of the electronic structure of the pentanuclear bow tie Au/Fe carbonyl cluster [Au{η-Fe(CO)}] together with its two one-electron reversible reductions. A new interpretation of the bonding pattern is provided with the help of inverted ligand field theory.

A Sulfonated Tweezer-Shaped Receptor Selectively Recognizes Caffeine in Water.

The selective recognition of caffeine in water among structurally related xanthines and purine or pyrimidine bases was achieved by a simple tweezer-shaped receptor featuring sulfonate hydrosolubilizing groups. The remarkable affinity for caffeine, among the highest reported thus far in the literature and larger than that shown by adenosine receptors of all subtypes, stems from a synergistic combination of hydrogen bonding, CH-π, and π-stacking interactions.

Easy and fast in situ functionalization of exfoliated 2D black phosphorus with gold nanoparticles.

Heterostructures of single- and few-layer black phosphorus (2D bP) functionalized with gold nanoparticles (Au NPs) have been recently reported in the literature, exploiting their intriguing properties and biocompatibility for catalytic, therapeutical and diagnostic applications. However, a deeper insight on the structural and electronic properties at the interface of the 2D bP/Au NP heterostructure is still lacking. In this work, 2D bP is functionalized with Au nanoparticles (NPs) through in situ deposition-precipitation heterogeneous reaction.

Interlayer Coordination of Pd-Pd Units in Exfoliated Black Phosphorus.

The chemical functionalization of 2D exfoliated black phosphorus (2D BP) continues to attract great interest, although a satisfactory structural characterization of the functionalized material has seldom been achieved. Herein, we provide the first complete structural characterization of 2D BP functionalized with rare discrete Pd units, obtained through a mild decomposition of the organometallic dimeric precursor [Pd(η-CH)Cl]. A multitechnique approach, including HAADF-STEM, solid-state NMR, XPS, and XAS, was used to study in detail the morphology of the palladated nanosheets (Pd/BP) and to unravel the coordination of Pd units to phosphorus atoms of 2D BP.

The chemistry of Ce-based metal-organic frameworks.

Metal-organic frameworks (MOFs) have gained widespread attention due to their modular construction that allows the tuning of their properties. Within this vast class of compounds, metal carboxylates containing tri- and tetravalent metal ions have been in the focus of many studies due to their often high thermal and chemical stabilities. Cerium has a rich chemistry, which depends strongly on its oxidation state.

On the comparison of oxygen and sulfur transfer reactivities in phosphine and phosphorene: the case of RSb(X) carriers (X = O or S).

Functionalization is one of the most powerful tools in materials science for the development of new and innovative materials with tailored properties purposefully designed to enhance the overall stability of the system. This is particularly true for exfoliated black phosphorus, which suffers from easy decomposition by air and moisture, hampering its highly desirable applications, especially in electronics. The present work suggests an innovative approach to the functionalization process of this 2D-material based on the selective introduction of chalcogen atoms on the material surface through a reaction with suitable molecular precursors such as stibine chalcogenides (R3Sb(X), X = O or S; R = organyl group).

Effective Recognition of Caffeine by Diaminocarbazolic Receptors.

Caffeine is a competitive inhibitor of adenosine receptors and possesses wide pharmacological activity. Artificial receptors recognizing caffeine potentially have a wide range of biomedical and industrial applications. Herein, we describe two structurally related and readily available artificial receptors: 1) a macrocyclic receptor, which binds caffeine with the unprecedented affinity of 9.

A new crystal form of the NSAID dexketoprofen.

Dexketoprofen [(2S)-2-(3-benzoylphenyl)propanoic acid], CHO, is the S-enantiomer of ketoprofen, a nonsteroidal anti-inflammatory drug (NSAID) that has analgesic, antipyretic and anti-inflammatory properties, and finds applications for the short-term treatment of mild to moderate pain. A new crystalline phase of dexketoprofen is reported. Its solid-state structure was determined by single-crystal X-ray diffraction (SCXRD).

Noncovalent Functionalization of 2D Black Phosphorus with Fluorescent Boronic Derivatives of Pyrene for Probing and Modulating the Interaction with Molecular Oxygen.

We studied the chemical-physical nature of interactions involved in the formation of adducts of two-dimensional black phosphorus (2D BP) with organoboron derivatives of a conjugated fluorescent molecule (pyrene). Time-resolved fluorescence spectroscopy showed a stabilization effect of 2D BP on all derivatives, in particular for the adducts endowed with the boronic functionalities. Also, a stronger modulation of the fluorescence decay with oxygen was registered for one of the adducts compared to the corresponding organoboron derivative alone.

A Perspective on Recent Advances in Phosphorene Functionalization and Its Applications in Devices.

Phosphorene, the 2D material derived from black phosphorus, has recently attracted a lot of interest for its properties, suitable for applications in materials science. The physical features and the prominent chemical reactivity on its surface render this nanolayered substrate particularly promising for electrical and optoelectronic applications. In addition, being a new potential ligand for metals, it opens the way for a new role of the inorganic chemistry in the 2D world, with special reference to the field of catalysis.

Modelling strategies for the covalent functionalization of 2D phosphorene.

This paper is a comparative outline of the potential acid-base adducts formed by an unsaturated main group or transition metal species and P atoms of phosphorene (P), which derives from black phosphorus exfoliation. Various possibilities of attaining a realistic covalent functionalization of the 2D material have been examined via DFT solid state calculations. The distribution of neighbor P atoms at one side of the sheet and the reciprocal directionalities of their lone pairs must be clearly understood to foreshadow the best possible acceptor reactants.

Polymer-Based Black Phosphorus (bP) Hybrid Materials by in Situ Radical Polymerization: An Effective Tool To Exfoliate bP and Stabilize bP Nanoflakes.

Black phosphorus (bP) has been recently investigated for next generation nanoelectronic multifunctional devices. However, the intrinsic instability of exfoliated bP (the bP nanoflakes) toward both moisture and air has so far overshadowed its practical implementation. In order to contribute to fill this gap, we report here the preparation of new hybrid polymer-based materials where bP nanoflakes (bPn) exhibit a significantly improved stability.

The atomic level mechanism of white phosphorous demolition by di-iodine.

A detailed mechanism of the I-induced transformation of white phosphorus into PI emerges from a DFT analysis. This multi-step process implies that at any stage one P-P and two I-I bonds cleavages, associated with the formation of two P-I bonds plus an in situ generated brand new I molecule. Significant electron transfer between the atoms is observed at any step, but the reactions are better defined as concerted rather than redox.

Hierarchy of Supramolecular Arrangements and Building Blocks: Inverted Paradigm of Crystal Engineering in the Unprecedented Metal Coordination of Methylene Blue.

The aromatic methylene blue cation (MB) shows unprecedented ligand behavior in the X-ray structures of the trigonal-planar (TP) complexes MBMCl (M = Cu, Ag). The two isostructural compounds were exclusively synthesized by grinding together methylene blue chloride and MCl solids. Only in the case of AuCl did the technique lead to a different, yet isoformular, Au derivative with separated MB and AuCl counterions and no direct N-Au linkage.

The Role of Water in the Preparation and Stabilization of High-Quality Phosphorene Flakes.

is shown to be degraded by water. However, the presence of a small amount of water allows the synthesis of high-quality material in liquid exfoliation of black phosphorus using dimethylsulfoxide as solvent. A phosphorus/water molar ratio between 1.

Fluorescence enhancement aided by metal ion displacement.

Immunosensors are one of the most common platform used in clinical laboratories, in particular the class based on Enzyme Linked Fluorescent Assays (ELFA) takes advantage of the amplification step of the enzyme, usually the alkaline phosphatase, that catalyzes the hydrolysis of a fluorescent substrate leading it to fluoresce. Anyway, they suffer in sensitivity if compared to molecular diagnostic or more modern in vitro diagnostic devices. In our work, a simple and effective mechanism to enhance the fluorescent signal, and hence the sensitivity of the system, is presented.

Octahedral co-carbide carbonyl clusters decorated by [AuPPh₃]⁺ fragments: synthesis, structural isomerism, and aurophilic interactions of Co₆C(CO)₁₂(AuPPh₃)₄.

The Co6C(CO)12(AuPPh3)4 carbide carbonyl cluster was obtained from the reaction of [Co6C(CO)15](2-) with Au(PPh3)Cl. This new species was investigated by variable-temperature (31)P NMR spectroscopy, X-ray crystallography, and density functional theory methods. Three different solvates were characterized in the solid state, namely, Co6C(CO)12(AuPPh3)4 (I), Co6C(CO)12(AuPPh3)4·THF (II), and Co6C(CO)12(AuPPh3)4·4THF (III), where THF = tetrahydrofuran.

Stabilization of the triphosphallyl ligand η3-P3{P(O)H} at iridium via alkaline activation of P4.

The selective functionalization of the polyphosphorus moiety Ph2PCH2PPh2PPPP present as a tetrahapto-ligand in complex [Ir(dppm)(Ph2PCH2PPh2PPPP)](+) (1, dppm=Ph2PCH2PPh2) was obtained by reaction of 1 with water under basic conditions at room temperature. The formation of the new triphosphaallyl moiety η(3)-P3{P(O)H} was determined in solution by NMR spectroscopy, and confirmed in the solid state by a single-crystal X-ray structure of the stable product [Ir(κ(2)-dppm)(κ(1)-dppm)(η(3)-P3{P(O)H})] (2). In solution, 2 has a fluxional behavior attributable to the four P atoms belonging to the tetraphosphorus moiety in 1 and exhibits a chemical exchange process involving the two PPh2 moieties of the same bidentate ligand, as determined by 1D and 2D NMR spectroscopy experiments carried out at variable temperature.

Intramolecular d10-d10 interactions in a Ni6C(CO)9(AuPPh3)4 bimetallic nickel-gold carbide carbonyl cluster.

The Ni6C(CO)9(AuPPh3)4 bimetallic carbide carbonyl cluster was obtained from the reaction of [Ni9C(CO)17](2-) with Au(PPh3)Cl. It contains a rare carbon-centered (distorted) Ni6C octahedral core decorated by four Au(PPh3) fragments. These are μ3-bonded to four contiguous Ni3-triangular faces and display weak intramolecular Au···Au d(10)-d(10) interactions.

Unprecedented tris-phosphido-bridged triangular clusters with 42 valence electrons. Chemical, electrochemical and computational studies of their formation and stability.

This paper presents the synthesis and structural characterization of the unprecedented tris-phosphido-bridged compounds Pt3(μ-PBu(t)2)3X3 (X = Cl, Br, I), having only 42 valence electrons, while up to now analogous clusters typically have 44e(-). The new species were obtained by an apparent bielectronic oxidation of the 44e(-) monohalides Pt3(μ-PBu(t)2)3(CO)2X with the corresponding dihalogen X2. Their X-ray structures are close to the D3h symmetry, similarly to the 44e(-) analogues with three terminal carbonyl ligands.