Analysis of Retracted Manuscripts in Chemistry: Errors vs Misconduct.

In this Viewpoint we discuss Chemistry manuscripts retracted during the 2001-2021 period (a total of 1292 journal articles retrieved from the Retraction Watch database). We showed that 58.5% of Chemistry manuscripts were retracted due to misconduct; of them, 40.

Publication practices during the COVID-19 pandemic: Expedited publishing or simply an early bird effect?

This study explores the evolution of publication practices associated with the SARS-CoV-2 research papers, namely, peer-reviewed journal and review articles indexed in PubMed and their associated preprints posted on bioRxiv and medRxiv servers: a total of 4,031 journal article-preprint pairs. Our assessment of various publication delays during the January 2020 to March 2021 period revealed the early bird effect that lies beyond the involvement of any publisher policy action and is directly linked to the emerging nature of new and 'hot' scientific topics. We found that when the early bird effect and data incompleteness are taken into account, COVID-19 related research papers show only a moderately expedited speed of dissemination as compared with the pre-pandemic era.

Structure and Properties of Sodium Enneaborate, Na[BO(OH)]·B(OH)·2HO.

Millions of tons of sodium borates are used annually by global industries in diverse applications important to modern society. The NaO-BO-HO phase diagram in the 0-100 °C temperature range contains 13 unique hydrated crystalline sodium borates, including five important industrial products. Structures were previously reported for each of these except for that having the highest boron content, known as sodium enneaborate, NaBO·11HO or 2NaO·9BO·11HO (1).

Solid-State Synthesis and Structure of the Enigmatic Ammonium Octaborate: (NH4)2[B7O9(OH)5]·3/4B(OH)3·5/4H2O.

The compound known since the 19th century as ammonium octaborate was structurally characterized revealing the ammonium salt of the ribbon isomer of the heptaborate anion, [B7O9(OH)5](2-), with boric acid and water molecules. Of composition (NH4)2B7.75O12.

An Efficient Halogen-Free Electrolyte for Use in Rechargeable Magnesium Batteries.

Unlocking the full potential of rechargeable magnesium batteries has been partially hindered by the reliance on chloride-based complex systems. Despite the high anodic stability of these electrolytes, they are corrosive toward metallic battery components, which reduce their practical electrochemical window. Following on our new design concept involving boron cluster anions, monocarborane CB11H12(-) produced the first halogen-free, simple-type Mg salt that is compatible with Mg metal and displays an oxidative stability surpassing that of ether solvents.

Novel synthetic approach to charge-compensated phosphonio-nido-carboranes. Synthesis and structural characterization of neutral mono and bis(phosphonio) nido-ortho-carboranes.

A number of monosubstituted n-(triphenylphosphonio)-7,8-dicarba-nido-undecaboranes (2a, n = 1; 2b, n = 3; 2c, n = 5; 2d, n = 9) were prepared via a cross-coupling reaction between the tetrabutylammonium iodo-7,8-dicarba-nido-undecaborates (1a-d) and PPh3 in the presence of a Pd(PPh3)4 catalyst. The substitution rate was found to depend on the iodine position in the carborane cage. Under similar conditions, the reaction of 5,6-diiodo- (3) and 9,11-diiodo-7,8-dicarba-nido-undecaborate (5) anions exclusively yielded the monosubstitution products 5-iodo-6-(triphenylphosphonio)-7,8-dicarba-nido-undecaborane (4) and 9-iodo-11-(triphenylphosphonio)-7,8-dicarba-nido-undecaborane (6), respectively.

Carborane-derived local anesthetics are isomer dependent.

Clinically there is a need for local anesthetics with a greater specificity of action on target cells and longer duration. We have synthesized a series of local anesthetic derivatives we call boronicaines in which the aromatic phenyl ring of lidocaine was replaced with ortho-, meta-, C,C'-dimethyl meta- and para-carborane clusters. The boronicaine derivatives were tested for their analgesic activity and compared with lidocaine using standard procedures in mice following a plantar injection.

Direct observation of bis(dicarbollyl)nickel conformers in solution by fluorescence spectroscopy: an approach to redox-controlled metallacarborane molecular motors.

As a continuation of work on metallacarborane-based molecular motors, the structures of substituted bis(dicarbollyl)nickel complexes in Ni(III) and Ni(IV) oxidation states were investigated in solution by fluorescence spectroscopy. Symmetrically positioned cage-linked pyrene molecules served as fluorescent probes to enable the observation of mixed meso-trans/dl-gauche (pyrene monomer fluorescence) and dl-cis/dl-gauche (intramolecular pyrene excimer fluorescence with residual monomer fluorescence) cage conformations of the nickelacarboranes in the Ni(III) and Ni(IV) oxidation states, respectively. The absence of energetically disfavored conformers in solution--dl-cis in the case of nickel(III) complexes and meso-trans in the case of nickel(IV)--was demonstrated based on spectroscopic data and conformer energy calculations in solution.

An unsolvated buckycatcher and its first dianion.

The X-ray crystallographic study of C60H28 consisting of two tethered corannulene bowls revealed a unique solid-state packing based on tight convex-concave π-π interactions. The controlled reduction of C60H28 resulted in the isolation and structural characterization of its dianion in the form of the rubidium salt that shows an entrapment of counterions by an anionic pincer.

Synthesis of closo- and nido-biscarboranes with rigid unsaturated linkers as precursors to linear metallacarborane-based molecular rods.

Several biscarborane-type derivatives of 8-iodo-1,2-dicarba-closo-dodecaborane (1), suitable as the precursors of linear metallacarborane-based molecular rods, were prepared. The synthesized closo-compounds contained two carborane moieties connected through a rigid linear unsaturated linker. The linkers were based on ethynylene and para-phenylene fragments and their combinations.

Synthesis of [closo-B12(OH)11NH3]-: a new heterobifunctional dodecaborane scaffold for drug delivery applications.

Effective utilization of [closo-B12H12](2-) derivatives in targeted drug delivery applications depends upon an efficient strategy to differentiate at least one of the 12 vertices on the B12(2-) core. Precursor molecules must also be able to withstand the initial harsh hydrogen peroxide treatment necessary for hydroxylation of the B-H vertices. We report here a method for preparation of the ammonio derivative [closo-B12(OH)11NH3](-) and also demonstrate its utility in construction of a targeted drug delivery scaffold.

Acid-induced opening of [closo-B10H10]2- as a new route to 6-substituted nido-B10H13 decaboranes and related carboranes.

Protonation of the polyhedral anion [closo-B(10)H(10)](2-) under superacidic conditions apparently generates an electrophilic intermediate, [B(10)H(13)](+), that forms 6-R-nido-B(10)H(13) (R = aryl, alkyl, triflate) derivatives by electrophilic aromatic substitution, C-H bond activation, or ion-pair collapse, respectively. The proposed mechanism of formation of the 6-R-nido-B(10)H(13) derivatives via the boranocation [B(10)H(13)](+) is discussed. The synthesis of carboranes, starting from 6-R-nido-B(10)H(13) decaboranes, and single-crystal X-ray diffraction analyses of several 6-R-nido-B(10)H(13) decaboranes and carboranes are described.

Carboranes increase the potency of small molecule inhibitors of nicotinamide phosphoribosyltranferase.

Herein we report the use of carboranes to significantly increase the potency of small molecule inhibitors of nicotinamide phosphoribosyltranferase (Nampt), an enzyme that is central to metabolism and cell survival. We compare the inclusion of carborane with other similarly sized substituents and demonstrate that, compared with their purely organic counterparts, these molecules exhibit up to 10-fold greater antiproliferative activity against cancer cells in vitro and a 100-fold increase in Nampt inhibition.

Novel approach to aminocarboranes by mild amidation of selected iodo-carboranes.

A mild protocol for the palladium-catalyzed Buchwald-Hartwig amidation of icosahedral carboranes is described. Employing 2-dicyclohexylphosphino-2'-(N,N-dimethylamino)biphenyl (1) as a ligand and K(3)PO(4) as a base, benzamide, trifluoroacetamide, acetamide, and formamide were coupled to a series of mono- and di-iodo carboranes furnishing the respective carborane derivatives in good to excellent yields. Subsequent base-mediated saponification of the trifluoroacetamide derivatives was shown to provide the free aminocarboranes.

Reversible Cu(4) <--> Cu(6) core interconversion and temperature induced single-crystal-to-single-crystal phase transition for copper(I) carboxylate.

The first example of a reversible [Cu(4)] <--> [Cu(6)] interconversion for polynuclear copper(I) complexes under controlled experimental settings is reported. It illustrates the key role of specific crystal growth conditions for accessing the target cluster nuclearity that consequently determines physical properties of the resulting solid state products. Thus, when copper(I) benzoate crystallizes from a 1,2-dichlorobenzene solution at room temperature, it forms [Cu(4)]-core based crystalline material, [Cu(4)(O(2)CC(6)H(5))(4)] (1).

Tetranuclear copper(I) clusters: impact of bridging carboxylate ligands on solid state structure and photoluminescence.

The X-ray crystallographic characterization and solid state photoluminescence (PL) study of three new tetranuclear copper(I) clusters, [Cu4(O2CR)4], R = (3-F)C6H4 (1), (2,3,4-F)3C6H2 (2), and CF3/C6F5 (3), revealed a dependence of PL on the structural type.

Corannulene vs. C60-fullerene in metal binding reactions: a direct DFT and X-ray structural comparison.

DFT calculations and X-ray crystallography were used to directly compare the reactivity of the convex carbon surfaces of C20H10-corannulene and the C60-fullerene toward the diruthenium(I,I) metal cluster.

The first hexanuclear copper(I) carboxylate: X-ray crystal structure and reactivity in solution and gas-phase reactions.

The carboxylate ligand-exchange reaction of copper(I) trifluoroacetate by 3,5-difluorobenzoate yielded a new product, [Cu(O2C(3,5-F)2C6H3)] (1). Single crystals of 1 suitable for X-ray structural characterization were obtained by sublimation-deposition procedures at 230 degrees C. An X-ray diffraction study revealed a remarkable planar hexanuclear copper(I) core supported by bridging carboxylates, the first such structural type among other known copper(I) carboxylates.

X-ray and density functional theory structural study of 1,3,5,7,9-penta-tert-butylcorannulene, C40H50.

The first X-ray structural characterization of an alkyl-substituted corannulene, namely, 1,3,5,7,9-penta-tert-butylcorannulene (C40H50), has been accomplished. The addition of bulky tert-butyl groups to the corannulene core flattens the bowl and affects the solid-state packing. The presence of two enantiomers, in addition to positional disorder of the C40H50 bowls in the solid-state structure, has prevented the acquisition of accurate geometric parameters of this open geodesic polyarene.