Volume 71, Issue 11

The monoclinic lithium platinum selenide Li 2 Pt 3 Se 4 was obtained via a multianvil high-pressure/high-temperature route at 8 GPa and 1200°C starting from a stoichiometric mixture of lithium nitride, selenium, and platinum. The structure of the ternary alkali metal-transition metal-selenide was refined from single-crystal X-ray diffractometer data: P 2 1 / c (no. 14), a =525.9(2), b =1040.6(2), c =636.5(2) pm, β =111.91(1)°, R 1=0.0269, wR 2=0.0569 (all data) for Li 2 Pt 3 Se 4 . Furthermore, the isostructural mineral phases jaguéite (Cu 2 Pd 3 Se 4 ) and chrisstanleyite (Ag 2 Pd 3 Se 4 ) were reinvestigated in their ideal stoichiometric ratio. The syntheses of the mineral phases were also carried out under multianvil conditions. Single-crystal data revealed a hitherto not described structural disorder of the transition metal atoms.

The rare earth fluoride borates RE 4 B 4 O 11 F 2 ( RE = Sm, Tb, Ho, Er) were synthesized in a Walker-type multianvil apparatus from the corresponding rare earth oxides and fluorides with boron oxide. Sm 4 B 4 O 11 F 2 was obtained under high-pressure/high-temperature conditions of 6 GPa/1100°C, Tb 4 B 4 O 11 F 2 at 7.5 GPa/1200°C, and Ho 4 B 4 O 11 F 2 and Er 4 B 4 O 11 F 2 at 9.5 GPa/1300°C. The single-crystal structure determinations showed that all compounds are isotypic to the known rare earth fluoride borates RE 4 B 4 O 11 F 2 ( RE = Pr, Nd, Eu, Gd, Dy). They crystallize in the monoclinic space group C 2 /c ( Z = 4). The structure is built up from BO 4 tetrahedra as well as BO 3 groups connected via common corners. Here, we report about the crystallographic characterization of these new compounds in comparison to the isotypic phases RE 4 B 4 O 11 F 2 ( RE = Pr, Nd, Eu, Gd, Dy).

An efficient protocol for oxidative C-3 arylation of coumarins with arylhydrazine has been developed using potassium permanganate as an oxidant. The arylated coumarins with different electronic properties were obtained in moderate to good yields. The developed protocol for direct C-3 arylation of coumarins could be extended to quinolinones.

Using the pendent organic ligand 1-butyl-1 H -(1,3,4)triazole (btz), two new polyoxometalate (POM)-based compounds, [Cu 3 (btz) 6 (H 2 O) 4 (H 3 P 2 W 18 O 62 ) 2 ]·6H 2 O ( 1 ) and [Cu 2 (btz)(tz)(H 2 O) 2 (SiMo 12 O 40 )]·5H 2 O ( 2 ) (tz=1 H -(1,3,4)triazole), have been synthesized under hydrothermal conditions. In compound 1 , three Cu II ions are fused by six btz ligands to form a linear tri-nuclear Cu II cluster, with water as bridging molecules. Two Wells-Dawson anions offer two terminal O atoms to link two apical Cu II atoms of this tri-nuclear cluster. In compound 2 , the btz and tz molecules connect Cu II ions to construct an infinite Cu II chain still with water molecules as bridges. The adjacent chains are linked by one type of POM anions to build a 2D grid-like layer. Considering the long-range coordinative Cu–O bonds, the other types of POM anions connect adjacent layers to form a 3D framework. The electrochemical and photocatalytic properties of compounds 1 and 2 were also studied.

In this work, we report the synthesis and characterization of CeO 2 nanoparticles as an efficient catalyst for the preparation of methyl 6-amino-5-cyano-4-aryl-2,4-dihydropyrano[2,3- c ]pyrazole-3-carboxylates via one-pot four-component condensation reaction of dimethyl acetylenedicarboxylate, hydrazine hydrate, malononitrile, and aldehydes in aqueous medium. The use of a non-hazardous organic solvent, easy recovery of the catalyst, compatibility with various functional groups, and high yield of the products make the protocol attractive, greener, and economic.

Ca 12 Ge 17 B 8 O 58 was prepared by high-temperature solid state synthesis at 1100°C in a platinum crucible from calcium carbonate, boric acid, and germanium(IV) oxide. The compound crystallizes in the tetragonal crystal system in the space group P 4̅ (No. 81) isotypically to Cd 12 Ge 17 B 8 O 58 . The structure was refined from single-crystal X-ray diffraction data: a = 15.053(8), c = 4.723(2) Å, V = 1070.2(2) Å 3 , R 1 = 0.0151, and wR 2 = 0.0339 for all data. The crystal structure of Ca 12 Ge 17 B 8 O 58 consists of [Ge 4 O 12 ] n chains composed of GeO 4 tetrahedra and GeO 6 octahedra. The chains are interconnected into a [Ge 4 O 10.5 ] n network via corner sharing. By additional [Ge(B 2 O 7 ) 4 ] 28– clusters, these units are connected to a three-dimensional [Ge 17 B 8 O 58 ] 24– framework. The open structure forms three types of tunnels with five-, six-, and seven-membered rings (MRs) along the c axis, where the Ca 2+ are located.

The hydrazide-hydrazones 6a–d and 7a , b were obtained by treating isatin ( 1 ) or its Mannich base 2 with hydrazides incorporating piperidine, morpholine, and piperazine units. The reaction of 1 and 2 with hydrazides related to triazenes having piperidine, morpholine, and 1,2,3,4-tetrahydroisoquinoline moieties gave 12a–c and 13a–c . Treatment of 1 and 2 with iminodiacetohydrazide ( 14 ) and ethylenediamine tetraacetohydrazide ( 18 ) afforded 15–17 and 19a , b , respectively. The Mannich reaction of the Schiff base 20 with formaldehyde and the appropriate hydrazide or bis(hydrazide) gave 21a , b and 22a , b . The hydrazides related to Schiff bases 20 and 26 were used as precursors in synthesis of compounds incorporating two 2-oxoindoline units or formazan moiety.

The ethyl acetate extracts prepared from the mycelia of three endophytic fungi Purpureocillium lilacinum, Aspergillus sp., and Fusarium sp., isolated from the roots of Rauvolfia macrophylla (Apocynaceae) were screened for their antiprotozoal activity in vitro against Plasmodium falciparum (NF54), Leishmania donovani , Trypanosoma brucei rhodesiense, and Trypanosoma cruzi . Amongst these extracts, the one from P. lilacinum showed potent antileishmanial activity against L. donovani (IC 50 value of 0.174 μg mL −1 ) with good selectivity (SI=94.9) toward the L6 cell line, whereas the other extracts were inactive and not selective. The fractionation and purification of the active extract from P. lilacinum by column chromatography over silica gel yielded a new ergochromone derivative ( 1 ), together with six known compounds: (22 E ,24 R )-stigmasta-5,7,22-trien-3- β -ol ( 2 ), (22 E ,24 R )-stigmasta-4,6,8(14),22-tetraen-3-one ( 3 ), emodin ( 4 ), chrysophanol ( 5 ), aloe-emodin ( 6 ), and palmitic acid, whose structures were elucidated spectroscopically. Compound 1 was tested in vitro for its antiparasitic activities against the above listed parasites and for its antimicrobial activity against Staphylococcus aureus , Bacillus cereus , Listeria monocytogenes , Escherichia coli , Providencia stuartii , Klebsiella pneumoniae , and Pseudomonas aeruginosa . The compound displayed potent antileishmanial activity against L. donovani with an IC 50 value of 0.63 μg mL −1 (0.87 μ m ) with good selectivity (SI=49.5) toward the L6 cell line. It also exhibited good antibacterial activity against three of the tested microbial strains B. cereus , E. coli ATCC879, and P. stuartii ATCC29916 with minimum inhibitory concentrations below 62.6 μg mL −1 . Compound 1 is thus a promising active compound that could be investigated for antileishmanial and antimicrobial drug development.

Two new metal–organic frameworks, namely, [Ag 2 (L)] n ( 1 ) and {[Ag 2.5 (L)(bpy) 2 ]·(NO 3 ) 0.5 ·(H 2 O) 4.5 } n ( 2 ), where H 2 L= N -pyrazinesulfonyl-glycine and bpy=4,4′-bipyridine, have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analysis. X-ray diffraction crystallographic analyses indicate that 1 displays a silver carboxylate-sulfonamide layer structure containing an uncommon heptanuclear [Ag 7 ] cluster wherein four silver(I) atoms form an Ag 4 plane with in a three-connected (6, 3) net. The molecular structure of 2 has three crystallographically independent two-coordinate Ag centers with an intersecting Ag-bpy chain structure in a six-connected (3, 6) or a four-connected (4, 4) topology. The L 2− ligand serves as a μ 7 -( η 2 -O,N), ( η 2 -O′,N′), O,O″,O″′,N,N″ ligand in 1 and as a μ 3 -( η 2 -O,N), N,O′ ligand in 2 . In the crystal, a 3D supramolecular architecture is formed by coordinative bonding in 1 , but through O–H···O bonding as well as π ··· π stacking in 2 . The two compounds show a combination of coordinative bonds, ligand-supported Ag···Ag interactions and weak Ag···O/N coordinative interactions in the solid state.