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This research aims to create innovative compounds that incorporate 1,2,4‐triazole and exhibit α‐glucosidase inhibitory potential. Similar to our previously reported series of N‐aryl 2‐{[5‐(naphthalen‐1‐ylmethyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl]thio}acetamide compounds, we explore here 4‐ethyl instead of 4‐phenyl as substituent. The synthesis process effectively yielded these compounds, with the highest yield reaching up to 91 % for compound N‐phenyl‐2‐{[5‐(naphthalen‐1‐ylmethyl)‐4‐ethyl‐4H‐1,2,4‐triazol‐3‐yl]thio}acetamide 5 a. Their structures were validated through various spectroscopic techniques such as IR, 1H‐NMR, 13C‐NMR, and HR‐MS spectra, and for compounds 3, 5 d, and 5 e by X‐ray diffraction. In vitro experiments revealed that only compound 5 g, marked by a 3‐hydroxy substitution on the N‐phenylacetamide moiety, demonstrated higher α‐glucosidase inhibitory potential (IC50=158.4±3.4 μM) compared to the positive control, acarbose (IC50=351.3±1.8 μM). Molecular docking studies also coincide with in vitro assay by uncovering a strong hydrogen bond with residue Asp1526 along with other hydrophobic interactions of compound 5 g in the α‐glucosidase binding pocket. Compound 5 g showed a free binding energy of −9.7 kcal/mol, contrasting with acarbose (−8.0 kcal/mol). Despite the modest biological activity, this research underscores the simplicity and convenience of the procedure for synthesizing 1,2,4‐triazole‐based compounds, and contributes a key feature to the structure‐activity relationship of the triazole scaffold in the α‐glucosidase pocket. [ABSTRACT FROM AUTHOR]

A new family of unsymmetrical boron chromophores chelated with two BF2 units, named BOPAM, has been developed via a one‐pot, three‐step reaction starting from commercially available thioamides via i) conversion to amidrazones, ii) condensation with pyrrole aldehydes, and iii) boron chelation. This synthetic pathway has been proven to be highly efficient, having a broad substrate tolerance and giving the BOPAM products high yield. Notably, some of the BOPAM dyes show interesting photophysical properties with fluorescence quantum yields up to 0.98 in toluene. A fine‐tuning of their emissive properties has been attained through tailored molecular design strategies guided by in‐depth computational investigations. Tailored substitution with electron‐donating groups at the BOPAM ring leads to the opening of a non‐radiative decay channel involving a dark state and consequently a significant quenching of the fluorescence. The study is complemented by exhaustive steady‐state and time‐resolved spectroscopic measurements. [ABSTRACT FROM AUTHOR]

Sulfur(VI)‐fluoride exchange (SuFEx) chemistry, an all‐encompassing term for substitution events that replace fluoride at an electrophilic sulfur(VI), enables the rapid and flexible assembly of linkages around a SVI core. Although a myriad of nucleophiles and applications works very well with the SuFEx concept, the electrophile design has remained largely SO2‐based. Here, we introduce S≡N‐based fluorosulfur(VI) reagents to the realm of SuFEx chemistry. Thiazyl trifluoride (NSF3) gas is shown to serve as an excellent parent compound and SuFEx hub to efficiently synthesize mono‐ and disubstituted fluorothiazynes in an ex situ generation workflow. Gaseous NSF3 was evolved from commercial reagents in a nearly quantitative fashion at ambient conditions. Moreover, the mono‐substituted thiazynes could be extended further as SuFEx handles and be engaged in the synthesis of unsymmetrically disubstituted thiazynes. These results provide valuable insights into the versatility of these understudied sulfur functionalities paving the way for future applications. [ABSTRACT FROM AUTHOR]

rsCherryRev1.4 has been reported as one of the reversibly photoswitchable variants of mCherry, and is an improved version with a faster off‐switching speed and lower switching fatigue at high light intensities than its precursor rsCherryRev. However, rsCherryRev1.4 still has some limitations such as a tendency to dimerize as well as complex photophysical properties. Here, the crystal structure of rsCherryRev1.4 was determined at a resolution of 2 Å and it was discovered that it forms a dimer that shows disulfide bonding between the protomers. Mutagenesis, gel electrophoresis and size‐exclusion chromatography strongly implicate Cys24 in this process. Replacing Cys24 in rsCherryRev1.4 resulted in a much lower tendency towards dimerization, while introducing Cys24 into mCherry correspondingly increased its dimerization. In principle, this finding opens the possibility of developing redox sensors based on controlled dimerization via disulfide cross‐linking in fluorescent proteins, even though the actual application of engineering such sensors still requires additional research. [ABSTRACT FROM AUTHOR]

The reaction of complexes [Pt(μ‐Cl)(arylolefin)]2 with various either weak σ‐donor LN,S,O ligands or strong σ‐donor NHCs ligands results in [PtCl(arylolefin)(LN,S,O)] with LN,S,O in a cis position to the C=C group (series A) or [PtCl(arylolefin)(NHC)] with NHC in a trans position to the C=C group (series B), respectively. The reaction directions are decided by the nature of the reactants, and not by the reaction conditions. Analyses of NMR spectra, XRD and DFT results indicate that the formation of series B is strongly dominated by electronic properties, while steric factors direct the reaction to form series A. The chemical shifts of ethylenic protons and carbons as well as the values of 2JPtH, 3JPtH for the allyl protons and the 3JPtH value for H6 in the aryl group are unambiguously different for series A and series B. In addition, one complex [Pt(μ‐Cl)(EtEug)]2 and five complexes [PtCl(arylolefin)(NHC)] have been characterized by single crystal XRD. [ABSTRACT FROM AUTHOR]

We report, herein, a palladium‐catalyzed cascade comprising carbopalladation, migratory insertion of isocyanide and triple bond activation followed by a nucleophilic attack (OR−) to construct difunctionalized acyl indoles. The process involves multiple bond formations via key palladium‐chemistry steps, to construct these bis‐heterocycles containing two privileged scaffolds (indole and oxindole) in a single operational step, along with attempts to generate enantioselectivity at a quaternary carbon center. The methodology also demonstrates a continuous‐flow process to synthesize aryl isocyanides within minutes and using them in a telescopic manner. [ABSTRACT FROM AUTHOR]

The field of peptide derivatization by metal‐catalyzed C−H activation has been mostly directed to modify the side chains, but poor attention has been given to the peptide backbone. Here we report a ruthenium‐catalyzed C−H activation/annulation process that can chemoselectively modify the peptide backbone producing functionalized isoquinolone scaffolds with high regioselectivity in a rapid and step‐economical manner. This strategy is characterized by racemization‐free conditions and the production of fluorescent peptides, and peptide conjugates to drugs, natural products and other peptide fragments, providing a chemical approach for the construction of novel peptide‐pharmacophore conjugates. Mechanistic studies suggest that amide bonds of peptide backbone act as the bidentate directing group to promote the C−H activation/annulation process. This report provides an unprecedented example of peptide backbone diversification and bioorthogonal ligation exploiting the power of ruthenium‐catalyzed C−H activation. [ABSTRACT FROM AUTHOR]

Anisotropic environments can drastically alter the spectroscopy and photochemistry of molecules, leading to complex structure‐function relationships. We examined this using fluorescent proteins as easy‐to‐modify model systems. Starting from a single scaffold, we have developed a range of 27 photochromic fluorescent proteins that cover a broad range of spectroscopic properties, including the determination of 43 crystal structures. Correlation and principal component analysis confirmed the complex relationship between structure and spectroscopy, but also allowed us to identify consistent trends and to relate these to the spatial organization. We find that changes in spectroscopic properties can come about through multiple underlying mechanisms, of which polarity, hydrogen bonding and presence of water molecules are key modulators. We anticipate that our findings and rich structure/spectroscopy dataset can open opportunities for the development and evaluation of new and existing protein engineering methods. [ABSTRACT FROM AUTHOR]

We report, herein, a palladium‐catalyzed cascade comprising carbopalladation, 1,4‐Pd‐migration and C(sp2)−C(sp2) bond formation to construct a variety of bis‐heterocyclic frameworks in a single operational step. The methodology provides a direct approach to introduce an oxadiazole core at a remote location without any functional group obligation, with moderate to good yields. [ABSTRACT FROM AUTHOR]

Five 2‐aroyl‐5‐bromobenzo[b]furan‐3‐ol compounds (two of which are new) and four new 2‐aroyl‐5‐iodobenzo[b]furan‐3‐ol compounds were synthesized starting from salicylic acid. The compounds were characterized by mass spectrometry and 1H NMR and 13C NMR spectroscopy. Single‐crystal X‐ray diffraction studies of four compounds, namely, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐fluorophenyl)methanone, C15H8BrFO3, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐chlorophenyl)methanone, C15H8BrClO3, (5‐bromo‐3‐hydroxybenzofuran‐2‐yl)(4‐bromophenyl)methanone, C15H8Br2O3, and (4‐bromophenyl)(3‐hydroxy‐5‐iodobenzofuran‐2‐yl)methanone, C15H8BrIO3, were also carried out. The compounds were tested for their in vitro cytotoxicity on the four human cancer cell lines KB, Hep‐G2, Lu‐1 and MCF7. Six compounds show good inhibiting abilities on Hep‐G2 cells, with IC50 values of 1.39–8.03 µM. [ABSTRACT FROM AUTHOR]

Nucleosides with a bi(hetero)aryl nucleobase have unique potential applications as antiviral drugs and molecular probes. The need for transition metal catalysis to synthesize these nucleosides from pre‐functionalized building blocks and the use of nucleobase protection groups results in expensive and tedious syntheses. Herein we report that 5‐imidazolyl‐uracil can be obtained by scalable Van Leusen imidazole synthesis and regioselectively introduced on ribose to obtain the desired nucleoside in a 5 step synthesis (total yield 55 %). The 5‐imidazolyl moiety leads to improved fluorescence properties. The only side‐product formed was characterized by 2D‐NMR and X‐ray crystallography and could be suppressed during synthesis in favor of the desired product. [ABSTRACT FROM AUTHOR]

A chemoselective rhodium(III)‐catalyzed cascade annulation for the construction of the indolizinone and quinolizinone scaffolds is developed. Diversification of peptidomimetics and oligopeptides is achieved in a rapid and step‐economical manner through the combination of Ugi reaction and microwave‐assisted rhodium(III)‐catalyzed intramolecular annulation via C(sp2)‐H activation without installing a directing group. [ABSTRACT FROM AUTHOR]

Four Wells–Dawson type metal‐substituted polyoxometalates (MSPs), 1:2 ZrIV‐Wells–Dawson [ZrIV(α2‐P2W17O61)]8– (1), 1:1 CoII‐Wells–Dawson [CoII(α2‐P2W17O61)]10– (2), 1:1 NiII‐Wells–Dawson [NiII(α2‐P2W17O61)]10– (3) and 1:1 CuII‐Wells–Dawson [CuII(α2‐P2W17O61)]10– (4), which differ in the nature of the imbedded metal ion, were examined in co‐crystallization experiments with a protein Hen Egg White Lysozyme (HEWL). Single crystal X‐ray structures of four noncovalent complexes between POMs and HEWL have been determined, and the influence of the type of substituted metal on the mode of POM binding to a protein was investigated. All crystal structures exhibited a high degree of similarity, suggesting that the interaction is largely independent on the nature of substituted metal within the same polyoxometalate (POM) archetype. The main driving force for the formation of the noncovalent complex is electrostatic attraction between POM and HEWL surface regions. Stabilization is further provided by direct and water mediated hydrogen bonding between terminal oxygen atoms of the POM framework and flexible HEWL residues. Single crystal X‐ray structures of four noncovalent complexes between POMs and HEWL were determined, and the influence of the type of substituted metal on the mode of POM binding to a protein was investigated. [ABSTRACT FROM AUTHOR]

Five new platinum(II) complexes bearing a eugenol and a quinoline derivative, namely [η2‐4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene]‐trans‐dichlorido(quinoline‐κN)platinum(II), [PtCl2(C15H20O4)(C9H7N)], (2), {η2‐4‐allyl‐2‐methoxy‐1‐[(propan‐2‐yloxy)carbonylmethoxy]benzene}‐trans‐dichlorido(quinoline‐κN)platinum(II), [PtCl2(C15H19O4)(C9H7N)], (3), [η2‐4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene]chlorido(quinolin‐8‐olato‐κ2N,O)platinum(II), [Pt(C9H6NO)Cl(C15H20O4)], (4), {η2‐4‐allyl‐2‐methoxy‐1‐[(propan‐2‐yloxy)carbonylmethoxy]benzene}chlorido(quinolin‐8‐olato‐κ2N,O)platinum(II), [Pt(C9H6NO)Cl(C15H20O4)], (5), and [η2‐4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene]chlorido(quinolin‐2‐carboxylato‐κ2N,O)platinum(II), [Pt(C10H6NO2)Cl(C15H20O4)], (6), have been synthesized and fully characterized spectroscopically. A single‐crystal X‐ray diffraction study was carried out for complexes (2) and (4)–(6). PrEug [or 4‐allyl‐2‐methoxy‐1‐(propoxycarbonylmethoxy)benzene] in (2), (4) and (6), and iPrEug (the propan‐2‐yloxy analogue of PrEug) in (3) and (5) coordinate with PtII at the ethylenic double bond of the allyl group. In (2)–(6), the donor N atom of the amine group occupies a trans position with respect to the double bond. A comparison of the IC50 values of 0.38–29.23 µM for (2)–(6) with cisplatin, as well as other platinum(II) complexes, indicates an excellent in vitro cytotoxicity against the KB, LU, Hep‐G2 and MCF‐7 cancer cell lines, with the highest cytotoxic effect (IC50 = 0.38–1.99 µM) being for complexes (4) and (5) bearing a quinolin‐8‐olate ligand. The syntheses and structures of five new platinum(II) complexes bearing (iso)propyl eugenoxyacetate and quinolines are presented, as well as their in vitro cytotoxicity on four human cancer cell lines. [ABSTRACT FROM AUTHOR]

Abstract: The effect of the protein environment on the formation and stabilization of an elusive catalytically active polyoxometalate (POM) species, K6[Hf(α2‐P2W17O61)] (1), is reported. In the co‐crystal of hen egg‐white lysozyme (HEWL) with 1, the catalytically active monomeric species is observed, originating from the dimeric 1:2 POM form, while it is intrinsically unstable under physiological pH conditions. The protein‐assisted dissociation of the dimeric POM was rationalized by means of DFT calculations. The dissociation process is unfavorable in bulk water, but becomes favorable in the protein–POM complex due to the low dielectric response at the protein surface. The crystal structure shows that the monomeric form is stabilized by electrostatic and water‐mediated hydrogen bonding interactions with the protein. It interacts at three distinct sites, close to the aspartate‐containing hydrolysis sites, demonstrating high selectivity towards peptide bonds containing this residue. [ABSTRACT FROM AUTHOR]

The syntheses of nine new 5‐iodosalicylic acid‐based 1,3,4‐oxadiazoline derivatives starting from methyl salicylate are described. These compounds are 2‐[4‐acetyl‐5‐methyl‐5‐(3‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6a), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6b), 2‐(4‐acetyl‐5‐methyl‐5‐phenyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl)‐4‐iodophenyl acetate, C19H17IN2O4 (6c), 2‐[4‐acetyl‐5‐(4‐fluorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C19H16FIN2O4 (6d), 2‐[4‐acetyl‐5‐(4‐chlorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C19H16ClIN2O4 (6e), 2‐[4‐acetyl‐5‐(3‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6f), 2‐[4‐acetyl‐5‐(4‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6g), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐methylphenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6h) and 2‐[5‐(4‐acetamidophenyl)‐4‐acetyl‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate (6i). The compounds were characterized by mass, 1H NMR and 13C NMR spectroscopies. Single‐crystal X‐ray diffraction studies were also carried out for 6c, 6d and 6e. Compounds 6c and 6d are isomorphous, with the 1,3,4‐oxadiazoline ring having an envelope conformation, where the disubstituted C atom is the flap. The packing is determined by C—H…O, C—H…π and I…π interactions. For 6e, the 1,3,4‐oxadiazoline ring is almost planar. In the packing, Cl…π interactions are observed, while the I atom is not involved in short interactions. Compounds 6d, 6e, 6f and 6h show good inhibiting abilities on the human cancer cell lines KB and Hep‐G2, with IC50 values of 0.9–4.5 µM. [ABSTRACT FROM AUTHOR]

We report herein an efficient gold(I)-catalyzed post-Ugi domino dearomatization/ ipso-cyclization/Michael sequence that enables access to libraries of diverse (hetero)arene-annulated tricyclic heterocycles. This process affords novel complex polycyclic scaffolds in moderate to good yields from readily available acyclic precursors with excellent chemo-, regio-, and diastereoselectivity. The power of this strategy has been demonstrated by the rapid synthesis of 40 highly functionalized polyheterocycles bearing indole, pyrrole, (benzo)furan, (benzo)thiophene, pyrazole, and electron-rich arene groups in two operational steps. [ABSTRACT FROM AUTHOR]

The synthesis of potassium (η2-4-allyl-2-methoxyphenol)trichloridoplatinate(II), K[PtCl3(C10H12O2)], ( 1), starting from Zeise's salt and Ocimum sanctum L. oil has been optimized. Starting from ( 1), three new platinum(II) complexes, namely (η2-4-allyl-2-methoxyphenol)chlorido(2-methylquinolin-8-olato-κ2 N, O)platinum(II), ( 2), (η2-4-allyl-2-methoxyphenol)chlorido(5-nitroquinolin-8-olato-κ2 N, O)platinum(II), ( 3), and (η2-4-allyl-2-methoxyphenol)chlorido(5,7-dichloroquinolin-8-olato-κ2 N, O)platinum(II), [Pt(C9H4Cl2NO)Cl(C10H12O2)], ( 4), containing eugenol and a quinolin-8-ol derivative (R-OQ), have been synthesized and characterized by elemental analyses, MS, IR, 1H NMR and NOESY spectra. For ( 1) and ( 4), single-crystal X-ray diffraction studies were also carried out. Complexes ( 2)-( 4) show good inhibiting abilities on three human cancer cell lines, i.e. KB, Hep-G2 and LU, with IC50 values of 1.42-17.8 µ M. Complex ( 3) gives an impressively high activity against KB, Hep-G2, LU and MCF-7, with IC50 values of 1.42-4.91 µ M, which are much lower than those of cisplatin and some other platinum(II) complexes. [ABSTRACT FROM AUTHOR]

This study presents a synthesis of 4 H-[1,2,3]triazolo[1,5- a]indol-4-ones. The key step in the synthesis of this new heterocyclic scaffold is an intramolecular cyclization via an unprecedented carbonylative C-H functionalization of 1-(2-bromoaryl)-1,2,3-triazoles. Isotopic labelling of the carbonyl carbon atom is possible using near stoichiometric amounts of 13CO. Additionally, an alternative pathway via carbonylative Sonogashira coupling followed by a two-step, one-pot azidation/cycloaddition is also investigated, giving rise to the same scaffold. [ABSTRACT FROM AUTHOR]

Crystallization of tacrine hydrochloride, an acetylcholinesterase inhibitor used during treatment of mild to moderate Alzheimer's disease, from a water:ethanol solution has resulted in an orthorhombic pseudopolymorph. This orthorhombic form which occurs as a dihydrate shows columns of stacking acridines together with continuous Cl—Owater—Owater—Cl chains and ladder-like ribbons composed of squares and hexagons. [ABSTRACT FROM AUTHOR]

Crystallization experiments with the dinuclear chelate ring complex di-μ-chlorido-bis[(η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)platinum(II)], [Pt2(C15H19O4)2Cl2], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform-diethyl ether or methylene chloride-diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile-κ N)(η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)chloridoplatinum(II) monohydrate, [Pt(C15H19O4)Cl(CH3CN)]·H2O, (η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)chlorido(dimethylformamide-κ O)platinum(II), [Pt(C15H19O4)Cl(C2H7NO)], and (η2-2-allyl-4-methoxy-5-{[(propan-2-yloxy)carbonyl]methoxy}phenyl-κ C1)chlorido(dimethyl sulfoxide-κ S)platinum(II), determined as the analogue {η2-2-allyl-4-methoxy-5-[(ethoxycarbonyl)methoxy]phenyl-κ C1}chlorido(dimethyl sulfoxide-κ S)platinum(II), [Pt(C14H17O4)Cl(C2H6OS)]. The crystal structures confirm that acetonitrile interacts with the PtII atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt-Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C-H...O and C-H...π interactions, but no π-π interactions are observed despite the presence of the aromatic ring. [ABSTRACT FROM AUTHOR]

A synthetic route towards homodiselenacalix[4]arene macrocycles is presented, based on the dynamic covalent chemistry of diselenides. The calixarene inner rim is decorated with either alkoxy or tert-butyl ester groups. Single-crystal X-ray analysis of two THF solvates with methoxy and ethoxy substituents reveals the high similarity of their molecular structures and alterations on the supramolecular level. In both crystal structures, solvent channels are present and differ in both shape and capacity. Furthermore, the methoxy-substituted macrocycle undergoes a single-crystal-to-single-crystal transformation during which the molecular structure changes its conformation from 1,3-alternate (loaded with THF/water) to 1,2-alternate (apohost form). Molecular modelling techniques were applied to explore the conformational and energetic behaviour of the macrocycles. [ABSTRACT FROM AUTHOR]

New nickel-containing ionic liquids were synthesized, characterized and their electrochemistry was investigated. In addition, a mechanism for the electrochemical synthesis of nanoparticles from these compounds is proposed. In these so-called liquid metal salts, the nickel(II) cation is octahedrally coordinated by six N-alkylimidazole ligands. The different counter anions that were used are bis(trifluoromethanesulfonyl)imide (Tf2N−), trifluoromethanesulfonate (OTf−) and methanesulfonate (OMs−). Several different N-alkylimidazoles were considered, with the alkyl sidechain ranging in length from methyl to dodecyl. The newly synthesized liquid metal salts were characterized by CHN analysis, FTIR, DSC, TGA and viscosity measurements. An odd-even effect was observed for the melting temperatures and viscosities of the ionic liquids, with the complexes with an even number of carbon atoms in the alkyl chain of the imidazole having a higher melting temperature and a lower viscosity than the complexes with an odd number of carbons. The crystal structures of several of the nickel(II) complexes that are not liquid at room temperature were determined. The electrochemistry of the compounds with the lowest viscosities was investigated. The nickel(II) cation could be reduced but surprisingly no nickel deposits were obtained on the electrode. Instead, nickel nanoparticles were formed at 100 % selectivity, as confirmed by TEM. The magnetic properties of these nanoparticles were investigated by SQUID measurements. [ABSTRACT FROM AUTHOR]

In the present study, we have investigated different strategies for diastereoselective synthesis of thia[n]- helicenes. We describe the introduction of different chiral auxiliaries at various positions and investigated their effect in the photocyclization reaction. Different chiral groups were placed at the sterically hindered position of the helical core and their interactions with various solvents and metals like copper were investigated. The use of CuI salts has led to high diastereoselectivity in the photocyclization process and we were successful in obtaining the thia[5]helicene in enantiomerically pure form in good yield. The single diastereomer obtained was characterized by X-ray crystallography. From the study of the barrier of racemization of these thia[5]-helicenes, the stability was found to be comparable to unsubstituted tetrathia[7]helicenes and substituted diazadithia[ 7]helicenes. This approach provides an easy access to enantiopure helicenes. [ABSTRACT FROM AUTHOR]

A one-step synthetic procedure for the radical CH alkylation of BODIPY dyes has been developed. This new reaction generates alkyl radicals through the oxidation of boronic acids or potassium trifluoroborates and allows the synthesis of mono-, di-, tri-, and tetraalkylated fluorophores in a good to excellent yield for a broad range of organoboron compounds. Using this protocol, multiple bulky alkyl groups can be introduced onto the BODIPY core thus creating solid-state emissive BODIPY dyes. [ABSTRACT FROM AUTHOR]

Successful co-crystallization of a noncovalent complex between hen egg-white lysozyme (HEWL) and the monomeric ZrIV-substituted Keggin polyoxometalate (POM) (Zr1 K1), (Et2NH2)3[Zr(PW11O39)] ( 1), has been achieved, and its single-crystal X-ray structure has been determined. The dimeric ZrIV-substituted Keggin-type polyoxometalate (Zr1 K2), (Et2NH2)10[Zr(PW11O39)2] ( 2), has been previously shown to exhibit remarkable selectivity towards HEWL hydrolysis. The reported X-ray structure shows that the hydrolytically active ZrIV-substituted Keggin POM exists as a monomeric species. Prior to hydrolysis, this monomer interacts with HEWL in the vicinity of the previously identified cleavage sites found at Trp28-Val29 and Asn44-Arg45, through water-mediated H-bonding and electrostatic interactions. Three binding sites are observed at the interface of the negatively charged Keggin POM and the positively charged regions of HEWL at: 1) Gly16, Tyr20, and Arg21; 2) Asn44, Arg45, and Asn46; and 3) Arg128. [ABSTRACT FROM AUTHOR]

A one-pot sequential A3-coupling-azidation-cyclisation approach leading to potentially biologically active diazepine analogues has been developed. The implementation of the A3-coupling reaction ensures diversity. Attention is given to this so far rarely studied structural motif of fused heterocyclic diazepines. [ABSTRACT FROM AUTHOR]

The crystal structures of three 5-alkenyl-2-arylthieno[3,2- b]thiophenes, namely 3,6-dibromo-5-(4- tert-butylstyryl)-2-(naphthalen-1-yl)thieno[3,2- b]thiophene, C28H22Br2S2, (I), 3,6-dibromo-5-(4-methylstyryl)-2-(naphthalen-1-yl)thieno[3,2- b]thiophene, C25H16Br2S2, (II), and 3,6-dibromo-2-(4- tert-butylphenyl)-5-(4-methylstyryl)thieno[3,2- b]thiophene, C25H22Br2S2, (III), have been determined in order to evaluate the geometry of the molecules. The π-conjugated system containing the thieno[3,2- b]thiophene skeleton, the ethylene bridge and the phenyl rings is almost planar. The aromatic ring directly attached to the thieno[3,2- b]thiophene moiety is not coplanar with the thieno[3,2- b]thiophene moiety itself due to steric hindrance of the bromo substituent. The crystal packings are characterized by π-π stacking [only for (II)] and C-Br...π interactions. The long axes of the molecules in (I) are oriented in two directions; for the two other structures the long axis is oriented in one direction only. [ABSTRACT FROM AUTHOR]

Evolution can increase the complexity of matter by self-organization into helical architectures, the best example being the DNA double helix. One common aspect, apparently shared by most of these architectures, is the presence of covalent bonds within the helix backbone. Here, we report the unprecedented crystal structures of a metal complex that self-organizes into a continuous double helical structure, assembled by non-covalent building blocks. Built up solely by weak stacking interactions, this alternating tread stairs-like double helical assembly mimics the DNA double helix structure. Starting from a racemic mixture in aqueous solution, the ruthenium(II) polypyridyl complex forms two polymorphic structures of a left-handed double helical assembly of only the Λ-enantiomer. The stacking of the helices is different in both polymorphs: a crossed woodpile structure versus a parallel columnar stacking. [ABSTRACT FROM AUTHOR]

The crystal structures of cis-dichlorido(ethylamine-κ N)(piperidine-κ N)platinum(II), [PtCl2(C2H7N)(C5H11N)], (I), cis-dichlorido(3-methoxyaniline-κ N)(piperidine-κ N)platinum(II), [PtCl2(C5H11N)(C7H9NO)], (II), and cis-dichlorido(piperidine-κ N)(quinoline-κ N)platinum(II), [PtCl2(C5H11N)(C9H7N)], (III), have been determined at 100 K in order to verify the influence of the nonpiperidine ligand on the geometry and crystal packing. The crystal packing is characterized by N-H...Cl hydrogen bonding, resulting in the formation of chains of molecules connected in a head-to-tail fashion. Hydrogen-bonding interactions play a major role in the packing of (I), where the chains further aggregate into planes, but less so in the case of (II) and (III), where π-π stacking interactions are of greater importance. [ABSTRACT FROM AUTHOR]

Physalis angulata L., an annual herb from the Solanaceae family, is widely used in popular medicine in tropical countries to treat a variety of diseases. Two products, ( X) and ( Y), were isolated from a crude CH2Cl2 extract of dried Congolese Physalis angulata L. plants and crystallized from acetone for structure elucidation. Compound ( X) corresponds to a physalin B dimer acetone solvate hydrate (2C28H30O9·C3H6O·0.22H2O), while compound ( Y) crystallizes as a mixed crystal containing two physalin B molecules which overlap with 5β,6β-epoxyphysalin B, also known as physalin F, and one acetone molecule in the asymmetric unit (1.332C28H30O9·0.668C28H30O10·C3H6O). Antiplasmodial activity, cytotoxic activity and selectivity indices were determined for crude extracts and the two isolated products ( X) and ( Y). [ABSTRACT FROM AUTHOR]

The article discusses research on a phenomenon of actuated conformational switching taking place in a single crystal of homodithiacalix[4]arene. It offers information on single-crystal-to-single-crystal transformations (SCSCT) occurring in metal-organic networks. It also talks about the occurrence of change in conformation of an organic cage induced by solvent.

Diazadithia[7]helicenes were synthesized from the readily available building block ethyl 7-chloro-8-formylthieno[3,2- f]quinoline-2-carboxylate by a Wittig reaction-photocyclization strategy. The helicene core was functionalized by nucleophilic aromatic substitution with a variety of nucleophiles (e.g., O-, N-, and C-centered) and palladium-catalyzed reactions such as Suzuki coupling and Buchwald-Hartwig amination. Racemization studies confirmed that the enantiopure forms of these [7]helicenes are conformationally stable compared to their lower analogues. The solid-state structures of the novel diazadithia[7]helicenes were determined by single-crystal X-ray diffraction. The crystal structures of these azathia[7]helicenes show columnar stacking in antiparallel fashion. The HOMO-LUMO gaps of the new compounds were determined on the basis of electrochemical and optical measurements. [ABSTRACT FROM AUTHOR]

The synthesis, structure and electrochemical properties of several silver-containing liquid metal salts have been investigated. These ionic liquids comprise of a silver-containing cation with a silver centre coordinated by two or more alkylamine ligands and a bis(trifluoromethylsulfonyl)imide (Tf2N) anion. With the monodentate amines tert-butylamine ( tBuAm), iso-butylamine ( iso-BuAm), sec-butylamine ( sec-BuAm), 2-ethylhexylamine (2-EtHexAm), di(2-ethylhexyl)amine and piperidine (pip), compounds with the formula [Ag(L)2][Tf2N] are formed, several of which are room-temperature ionic liquids and all melt at or below 100 °C. In the case of [Ag(L)2][Tf2N] (L= tBuAm, iso-BuAm and pip), single-crystal X-ray diffraction shows that, in the solid state, the silver centres are two-fold coordinated by two amine ligands and the anion and cation exist as separated ion pairs. With ethylenediamine (en), two different compounds were formed, depending on the silver-to-ligand ratio and their structures were elucidated by X-ray diffraction. [Ag(en)][Tf2N] has a very high melting point and is polymeric in the solid state, with en ligands coordinated to different silver(I) centres, creating one-dimensional chains. [Ag(en)2][Tf2N], on the other hand, is a room-temperature ionic liquid, with four-coordinate silver(I) centres, but is actually polymeric in the solid state. The electrodeposition behaviour of [Ag(2-EtHexAm)2][Tf2N] and [Ag(en)2][Tf2N] was investigated both at room temperature and at 90 °C and it was possible to achieve very high current densities in unstirred solutions and to electrodeposit closed, crack-free, silver coatings. A crystal of [Ag2(en)Cl2] was obtained from a solution of [Ag(en)][Tf2N] in deuterochloroform and its structure is described. [ABSTRACT FROM AUTHOR]

Rh and Ir complexes that contain meso-( p-methoxyphenyl)dipyrromethene (dipy) and phenylpyridine (ppy) ligands {i.e., [Rh(dipy)3], [Rh(ppy)2(dipy)] and [Ir(ppy)2(dipy)]} have been prepared and their electrochemical and luminescence behaviour are discussed and compared to results of theoretical calculations. The oxidation and reduction potentials, in agreement with the time-dependent (TD)-DFT calculations, indicate clearly that the HOMO-LUMO transitions are governed by the dipy ligand, which controls also the triplet excited-state emission. However, in luminescence, the two Rh complexes exhibit, in addition to a dipy-centred triplet emission, luminescence from the singlet excited state, which predominates at room temperature, due to a less important influence of the heavy-metal effect in Rh than in Ir complexes. Although the TD-DFT results are in very good agreement with the experimental emission spectra from the dipy-centred triplet excited state, this is not the case for the absorption spectra of the complexes and free dipy ligand. [ABSTRACT FROM AUTHOR]

Ser/Thr protein phosphatase 1 (PP1) is a single-domain hub protein with nearly 200 validated interactors in vertebrates. PP1-interacting proteins (PIPs) are ubiquitously expressed but show an exceptional diversity in brain, testis and white blood cells. The binding of PIPs is mainly mediated by short motifs that dock to surface grooves of PP1. Although PIPs often contain variants of the same PP1 binding motifs, they differ in the number and combination of docking sites. This molecular-lego strategy for binding to PP1 creates holoenzymes with unique properties. The PP1 binding code can be described as specific, universal, degenerate, nonexclusive and dynamic. PIPs control associated PP1 by interference with substrate recruitment or access to the active site. In addition, some PIPs have a subcellular targeting domain that promotes dephosphorylation by increasing the local concentration of PP1. The diversity of the PP1 interactome and the properties of the PP1 binding code account for the exquisite specificity of PP1 in vivo. [ABSTRACT FROM AUTHOR]

The crystal structure of the on-state of PDM1-4, a single-mutation variant of the photochromic fluorescent protein Dronpa, is reported at 1.95 Å resolution. PDM1-4 is a Dronpa variant that possesses a slower off-switching rate than Dronpa and thus can effectively increase the image resolution in subdiffraction optical microscopy, although the precise molecular basis for this change has not been elucidated. This work shows that the Lys145Asn mutation in PDM1-4 stabilizes the interface available for dimerization, facilitating oligomerization of the protein. No significant changes were observed in the chromophore environment of PDM1-4 compared with Dronpa, and the ensemble absorption and emission properties of PDM1-4 were highly similar to those of Dronpa. It is proposed that the slower off-switching rate in PDM1-4 is caused by a decrease in the potential flexibility of certain β-strands caused by oligomerization along the AC interface. [ABSTRACT FROM AUTHOR]

The article presents a research study on the organic compound, hexakis(adamantyktrimethyl-ammonium) cyclooctasilicate tetrateracontahydrate. It discusses an experiment that discovers the crystal structure and association of the subject compound to zeosils and the clathrate hydrates. Several sub groups of templates used to synthesize silicate hydrate materials include N-methyl quarternary amines, other quaternary amines and the metal-ethylenediamine complexes.

Cyclohexene nucleic acid (CeNA) building blocks can be introduced into natural DNA sequences without a large conformational influence because of the ability of the six-membered sugar ring to mimic both the C2′- endo and C3′- endo conformations of the naturally occurring ribofuranose sugar ring. The non-self-complementary DNA sequence d[GCG(xT)GCG]/d(CGCACGC) with one incorporated CeNA (xT) moiety crystallizes in two forms: orthorhombic and tetragonal. The tetragonal form, which diffracts to 3 Å resolution, is a kinetically stable polymorph of the orthorhombic form [Robeyns et al. (2010), Artificial DNA, 1, 1-7], which diffracts to 1.17 Å resolution and is the thermodynamically stable form of the CeNA-incorporated duplex. Here, the two structures are compared, with special emphasis on the differences in crystal packing and the irreversible conversion of the kinetic form into the high-resolution diffracting thermodynamic form. [ABSTRACT FROM AUTHOR]