Volume 64, Issue 9

2,3,5-Triphenyltetrazolium hexachlorophosphate, [C 19 H 15 N 4 ] + [PCl 6 ] − , [TPT] + [PCl 6 ] − (1), and 2,3,5-triphenyltetrazolium dichlorophosphate(V), [C 19 H 15 N 4 ] + [PO 2 Cl 2 ] − , [TPT] + [PO 2 Cl 2 ] − (2), were synthesized by reactions of anhydrous 2,3,5-triphenyltetrazolium chloride, [TPT] + Cl − , and 2,3,5-triphenyltetrazolium chloride monohydrate [TPT] + Cl− ・H 2 O, with PCl 5 in dry acetonitrile, and their crystal structures were determined by single-crystal X-ray diffraction analysis. In the title compounds, the [TPT] + cations show a face-to-face stacked orientation between the phenyl rings of neighboring molecules, which is caused by intermolecular π ・ ・ ・π interactions. The crystal structure of compound 1 consists of layers of 2,3,5-triphenyltetrazolium cations and hexachlorophosphate anions. In compound 2 the tetrahedral [PO 2 Cl 2 ] − anions exhibit approximate C 2v symmetry with P-O bond lengths from 1.454 to 1.463 Å and P-Cl bond lengths from 2.038 to 2.050 Å . The Raman spectrum of compound 1 was recorded, and the assignment of the [PCl 6 ] − Raman modes is proposed. Graphical Abstract Formation and Crystal Structure of 2,3,5-Triphenyltetrazolium Hexachlorophosphate and Dichlorophosphate(V), [TPT] + [PCl 6 ] – and [TPT] + [PO 2 Cl 2 ] –

1,1-Organoboration of dialkyn-1-ylsilanes using triethylborane, BEt 3 , and 9-ethyl-9-borabicyclo [3.3.1]nonane, Et-9-BBN, was carried out at elevated temperatures, 100 - 120 °C. These reactions afforded selectively silole derivatives bearing the dialkylboryl group in 3-position. The siloles are formed via intermolecular 1,1-alkylboration, followed by intramolecular 1,1-vinylboration. Two examples of boryl-substituted siloles were treated with an excess of acetic acid at ambient temperature to afford the respective protodeborylated compounds. All new compounds were characterized in solution by multinuclear magnetic resonance spectroscopy ( 1 H, 13 C, 11 B and 29 Si NMR). Graphical Abstract Syntheses of 1,1-Organo-substituted Silole Derivatives. 1,1-Ethylboration, 1,1-Vinylboration and Protodeborylation

The synthesis and single crystal X-ray structures of eight Ag I , Hg II , and Pt II complexes with the thiacrown ethers maleonitrile-tetrathia-12-crown-4 (mn12S 4 ), maleonitrile-tetrathia-13-crown-4 (mn13S 4 ), and maleonitrile-pentathia-15-crown-5 (mn15S 5 ) (1) are reported. The ligand mn15S 5 was synthesized for the first time and characterized by X-ray diffraction. With silver(I) perchlorate and silver(I) tetrafluoroborate it forms the chiral complexes [Ag(mn15S 5 )]ClO 4 ・CH 3 NO 2 (2) and [Ag(mn15S 5 )]BF 4 ・CH 3 NO 2 ・0.25H 2 O (3) with half-sandwich moieties. AgI is located in a distorted tetrahedral coordination environment, involving three sulfur atoms of the crown cycle and a fourth one of the adjacent half-sandwich moiety, forming a helical structure. The reaction of Hg(ClO 4 ) 2 with mn13S 4 yielded the dinuclear complex [Hg 2 (mn13S 4 ) 3 ](ClO 4 ) 4 (4) containing two half-sandwich moieties with a third ligand molecule as a bridging unit. Mercury(II) chloride and mercury(II) iodide react with mn12S 4 and mn13S 4 to form complexes of the general composition [HgX 2 (L)] (X = Cl, I; L = mn12S 4 , mn13S 4 ): [HgCl 2 (mn12S 4 )] (5), [HgI 2 (mn12S 4 )] (6), [HgCl 2 (mn13S 4 )] (7) or [HgX 2 (L) 2 ] (X = I; L = mn13S 4 ): [HgI 2 (mn13S 4 ) 2 ] (8). Only one or two sulfur atoms of the ligand are involved in the complexation, and chain or ribbon structures are formed. In these compounds the HgX 2 units (X = Cl, I) are preserved, coordinated by sulfur atoms of bridging mn12S 4 or mn13S 4 ligands. In all complexes of this type, the metal atoms are not coordinated inside the cavity, but in an exocyclic mode, because the diameter of the macrocycle is too small. Additionally, the PtCl 2 complex of mn12S 4 was investigated, where Pt II is coordinated in an exocyclic mode forming the complex [PtCl 2 (mn12S 4 )] (9). Two of the four sulfur atoms of the macrocycle are bonded to the metal giving together with both chlorine atoms a square-planar coordination geometry. Together with a long-range interaction with a further sulfur atom of the macrocycle a square-pyramidal coordination environment is formed. Graphical Abstract Ag(I)-, Hg(II)- und Pt(II)-Komplexe von Maleonitril-thiakronenethern/ Ag(I), Hg(II) and Pt(II) Complexes with Maleonitrile-thiacrown Ethers

A unique 2D sheet metal-organic framework, [Cu 3 (bpdc) 4/2 (pdon) 2 (H 2 O) 6 ]·2ClO 4 (2), has been synthesized by the hydrothermal reaction of pdon with Cu(ClO 4 ) 2 (bpdc = 2,2´-bipyridyl-3,3´- dicarboxylate, pdon = 1,10-phenanthroline-5,6-dione). Compound 2 crystallizes in the orthorhombic chiral space group P2 1 2 1 2, with the cell parameters: a = 12.3596(11), b = 25.978(2), c = 7.9585(7) Å , V = 2555.3(4) Å 3 [R1 = 0.068 and wR2 = 0.172]. It represents a novel metal-organic framework comprising of the mixed ligands of pdon and bpdc, where the cupric atoms are bridged by alternating the μ 2 - and μ 4 -bpdc groups into two-dimensional positively charged layers. The bpdc ligand has resulted from the in situ oxidative carbon-carbon bond cleavage of the pdon ligand. Compound 2 displays antiferromagnetic interactions. Above 40 K, χm −1 obeys the Curie-Weiss law with C = 1.37 cm 3 Kmol −1 and Θ = −13.95 K. Graphical Abstract Structure and Magnetic Properties of a Two-dimensional Metal-Organic Framework: [Cu 3 (bpdc) 4/2 (pdon) 2 (H 2 O) 6 ] · 2ClO 4

The electro-reduction of a series of Co(III) complexes of the type cis-β -[Co(trien)(4-R-Py)Cl]Cl 2 , where trien = triethylenetetramine and R = H, Me, Et, t-Bu, COMe, and CN, has been studied in propan-2-ol/water and 1,4-dioxane/water binary mixtures. The redox potential (E 1/2 ) data were correlated with solvent and structural parameters with an aim to shed some light on the mechanism of these reactions. Correlation of E 1/2 with macroscopic solvent parameters indicated that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The reduction of Co(III) to Co(II) in these complexes was observed to become increasingly easier with an increase in the dipolarity/ polarizability of the medium as evidenced by the Kamlet-Taft correlation. The difference in the relative lenience of the reduction has been explained using the difference in H-bonding properties of the medium. Graphical Abstract Differential Pulse Voltammetric Studies of Some Mixed-ligand Co(III) Complexes in Aquo-Organic Solvent Media Possessing Different Hydrogen Bonding Properties

To investigate the intermolecular interactions of ligands in lead(II) complexes featuring stereochemical activity of the lone electron pair and noncovalent donor-acceptor interactions giving rise also to multidimensional networks, the compounds [Pb 2 (phen) 2 (mbtfa) 4 ] (1) and [Pb 2 (dmp) 2 (mbtfa) 4 ] (2) (phen, dmp and mbtfa − for 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline and 4-methoxybenzoyltrifluoroacetonate ligands, respectively) have been prepared and characterized by elemental analysis and their crystal structures investigated. The structures show the coordination number of Pb(II) to be seven and eight, respectively. Supramolecular structures of 1 and 2 are realized by weak directional intermolecular interactions. Graphical Abstract Synthesis and Characterization of Lead(II) Complexes with the 4-Methoxybenzoyltrifluoroacetonate Ligand

Monoclinic holmium sesquioxide B-Ho 2 O 3 and orthorhombic holmium orthogallate HoGaO 3 were synthesized in a Walker-type multianvil apparatus under high-pressure / high-temperature conditions of 11.5 GPa / 1250 °C and 7.5 GPa / 1250 °C, respectively. Both crystal structures could be determined by single-crystal X-ray diffraction data, collected at r. t. The monoclinic holmium oxide crystallizes in the space group C2/m (Z = 6) with the parameters a = 1394.7(3), b = 350.83(7), c = 865.6(2) pm, β = 100.23(3)°, R1 = 0.0517, wR2 = 0.1130 (all data), and the orthorhombic compound HoGaO 3 in Pnma (Z = 4) with the parameters a = 553.0(2), b = 753.6(2), c = 525.4(2) pm, R1 = 0.0222, and wR2 = 0.0303 (all data). Graphical Abstract High-pressure Syntheses and Crystal Structures of Monoclinic B-Ho 2 O 3 and Orthorhombic HoGaO 3

The crystal structures of heptamethylenediammonium bis(saccharinate) monohydrate, [H 3 N - (CH 2 ) 7 -NH 3 ](sac) 2 ・H 2 O (1) and octamethylenediammonium bis(saccharinate) hemihydrate, [H 3 N- (CH 2 ) 8 -NH 3 ](sac) 2 ・0.5H 2 O (2), were determined by single-crystal X-ray diffraction methods. Compound 1 crystallizes in the triclinic space group P1̄ with 2 molecules per unit cell, and 2 in the monoclinic space group P2 1 /a with Z = 4. The saccharinate moiety is planar in both compounds presenting bonding characteristics comparable to those found in other saccharinate salts. The ionic crystals are further stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectra of the adducts are briefly discussed in comparison with those of the constituent molecules. Graphical Abstract Two New Supramolecular Assemblies Obtained by Reaction Between Saccharin and Long-chain Diamines

An exploration into the utility of the thermally-induced (metal oxide-mediated) CO 2 extrusion and subsequent rearrangement of N-acyl-1,3-oxazolidin-2-ones to form 2-aryl(alkyl)-2-oxazolines is described. The reaction is found to give moderate yields of the corresponding 2-oxazolines. Attempts to employ the above methodology to give enantiopure (R)- or (S)-2,5-diphenyl-2-oxazoline (the latter form being the natural product Oxytriphine) from enantiopure (and crystallographically characterised) (S)-N-benzoyl-5-phenyl-2-oxazolidinone led to the isolation of an essentially racemic product. These protocols are compared to other common methods used to form the oxazoline ring system and are placed into context with previous investigations of such ring forming reactions. Graphical Abstract An Exploration of the Metal Oxide-assisted Decomposition and Rearrangement of N-Acyl-1,3-oxazolidin-2-ones Leading to 2-Aryl-2-oxazolines [1]

The catalytic activity of benzamidine during an aldol reaction was reversibly switched on and off with CO 2 as an orthogonal signal without affecting the converted substrate or products Graphical Abstract Reversible Regulation of a Benzamidine-catalyzed Aldol Reaction by CO 2

N-Phthaloyl-alanylazide reacts smoothly with trialkyl phosphites producing the corresponding α- aminophosphates. With dialkyl hydrogenphosphonates in the presence of benzoyl peroxide, amidophosphates were the isolated products whereas the oxoaziridin-1-yl-phosphonic diamide was preferentially provided from the reaction of the azide with tris(dimethylamino)phosphine. The azide was also allowed to react with α-keto-, α-ethoxycarbonyl- and α-cyanomethylenetriphenylphosphorane to give the corresponding linear disubstituted 1,2,3-triazoles. Screening results of antibiotic potency for the products were discussed in terms of structure-activity relationship (SAR), and an attempt was made to define the structural features for lead compounds. Graphical Abstract Synthesis of Antimicrobial N-Phthaloyl-alanyl-derived Amidophosphates and Triazoles

Diethyl 2,2´-thiocarbonyl-bis(azanediyl)dibenzoate was synthesized from the reaction of ethyl anthranilate with thiophosgene. Its treatment with sodium ethoxide in ethanol at room temperature gave ethyl 2-(4-oxo-2-thioxo-1,2-dihydroquinazolin-3(4H)-yl) benzoate, whereas in the presence of ethyl nitroacetate and under the same reaction conditions, the corresponding bis(quinazolin)disulfide was formed. Its structure was confirmed by IR, 1 H and 13 C NMR spectroscopy elemental analysis and single crystal X-ray structure determination. Graphical Abstract Synthesis and Single Crystal X-Ray Structure of Bis[4-oxo-3- (2-ethoxycarbonylphenyl)-3,4-dihydroquinazolin-2-yl]disulfide

Two new ellagic acid derivatives, named panconosides A (1) andB(2) were isolated from Pancovia pedicellaris together with eleven known compounds (3 - 13). The structures of 1 and 2, as well as those of the known compounds were established by spectroscopic methods and by comparison with previously reported data. Compounds 1 and 2 were tested in vitro for their antibacterial potential against six strains of microorganisms: Micrococcus luteus, Streptococcus ferus, Streptococcus minor, Escherichia coli, Bacillus subtilis, and Pseudomonas agarici. They were found to exhibit moderate antibacterial activity against all the tested strains compared to standard drugs. Graphical Abstract Antibacterial Ellagic Acid Derivatives and Other Constituents from Pancovia pedicellaris

A new chlorine-containing glucosyl-fused compound, crassifoside H (1), was isolated from the EtOH extract of the rhizomes of Curculigo glabrescens. The structure was established on the basis of MS, IR, 1D and 2D NMR experiments. In addition, seven known compounds (2 - 8) were isolated and identified by spectroscopic analysis and comparison of their spectral data with those reported previously. All the compounds were isolated from this plant for the first time. The free radical scavenging activity of the isolated compounds was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Compounds 1 and 2 showed strong radical scavenging activities. The primary structure-activity relationship is also discussed. Graphical Abstract A New Chlorine-containing Glucosyl-fused Compound from Curculigo glabrescens

A major triterpenoid saponin was isolated from the leaves extract of Acer velutinum. This compound was characterized as 21β ,22α-O-diangeloylprotoaescigenin 3-O-[β -D-glucopyranosyl- (1→2)][β -D-glucopyranosyl-(1→4)]-β -D-glucuronopyranosyl acid. Its structure was elucidated by 1 H, gCOSY, ROESY, gHSQC, gHMBC NMR as well as ESI-MS experiments. Isolated saponin exhibited in vitro cytotoxicity against HL-60, B16-F0 and BALB/3T3 cell lines. Graphical Abstract A Major Saponin from Leaves Extract of Acer velutinum

Two new metabolites, named crispacolide (1) and 3-acetyl-4-hydroxymethyl-tetrahydrofuran (2), were isolated from the fruiting bodies of basidiomycete Sparassis crispa (Wulf.) Fr. The structures and stereochemistry were established on the basis of spectroscopic means Graphical Abstract Two New Metabolites from Basidiomycete Sparassis crispa

The borazocine (ClB=NCMe 3 ) 4 crystallizes in the monoclinic system, space group C2/c with Z = 6, i. e. there are two independent molecules in the unit cell. The first molecule has no crystallographic symmetry, while the second molecule is characterized by a twofold axis which generates the (ClB= NCMe 3 ) 4 molecule from the fragment (ClB=NCMe 3 ) 2 . The molecules are tub-shaped showing alternating longer and shorter B-N bonds. Compared with the borazocine (N 3 B= NCM 3 ) 4 the BN bonds of (ClB=NCMe 3 ) 4 are on average shorter than those of the azide derivative. Although B-N bond lengths and N-B-N and B-N-B bond angles in both molecules of (ClB=NCMe 3 ) 4 are identical within the limits of the standard deviation, the opposite B 2 N 2 planes differ significantly for the two independent molecules. Graphical Abstract The Molecular Structure of 1,3,5,7- Tetra(tert-butyl)-2,4,6,8-tetra(chloro)- borazocine [1]