Volume 67, Issue 8

The new compound [Cr 3 (dpa) 4 Cl 2 ][CuCl 2 ] (1) (dpa = di-2,2'-pyridylamido) was synthesized by reacting Cr 2 (dpa) 4 and anhydrous CuCl 2 in dry tetrahydrofuran. Partial oxidation of Cr 2 (dpa) 4 by Cu(II) forms Cr 3+ ions, which coordinate to the free N donor atoms of the dpa ligands, and led to the formation of a trinuclear chain cation [Cr 3 (dpa) 4 Cl 2 ] + . Recrystallization from CH 2 Cl 2 /ethyl ether yielded dark-brown, block-shaped crystals suitable for X-ray structure determination (Pccn (no. 56), a=1246:8(5), b=1487:3(3), c=2184:8(1) pm, V =4051.6(8) ·10 6 pm 3 , Z =4). The crystal structure is composed of discrete [Cr 3 (dpa) 4 Cl 2 ] + cations and [CuCl 2 ] - anions. The Cr 3 chain comprises quadruply-bonded diamagnetic (Cr 2 ) 4+ dimers and a pseudo-octahedrally coordinated, paramagnetic Cr 3+ ion, manifesting itself in the effective magnetic moment μ eff of 3:54μ B (d3, S = 3=2) and the almost ideal Curie-paramagnetic behavior observed between 2 and 300 K with a Weiss constant θ = -0:25(4)K and χ0 = 4:9(7)×10 -4 emu mol -1 Graphical Abstract Synthesis, Structure Determination, and Magnetic Properties of [Cr 3 (dpa) 4 Cl 2 ][CuCl 2 ], a Compound Comprising a Trinuclear Chain Cation

Reaction of chiral N-heterocyclic chlorophosphines with lithium diphenylphosphide or of achiral N-heterocyclic chlorophosphines with optically active lithium menthyl phosphide produces chiral N-heterocyclic diphosphines which can be utilized in subsequent diphosphination reactions with activated alkenes or alkynes. The reaction with alkynes proceeds stereospecifically to produce Zethylene- 1,2-bisphosphines which are readily converted to nickel(II) or palladium(II) complexes. Reactions with alkenes are synthetically less useful as the addition proceeds without any chiral induction at the newly formed stereocenters to yield inseparable mixtures of diastereomeric products. The molecular structures of chiral Z-ethylene-1,2-bisphosphine complexes and of a chiral N-heterocyclic chlorophosphine have been determined by single-crystal X-ray diffraction Graphical Abstract On the Synthesis and Addition Reactions of Chiral N-Heterocyclic Diphosphines

Two chain-like coordination polymers, namely, {[Zn(saes)(4,4'-bipy)(H 2 O)]·H 2 O} n (1) and {[Cd (Hsaes) 2 (4,4'-bipy)(H 2 O) 2 ]·2H 2 O} n (2), where H 2 saes=2-(2-hydroxybenzylideneamino)ethanesulfonic acid and 4,4'-bipy=4,4'-bipyridine, have been synthesized and characterized by singlecrystal X-ray diffraction, IR spectroscopy, elemental, thermogravimetric and photoluminescence analysis. X-Ray diffraction analyses indicate that 1and 2display octahedral metal centers with N 3 O 3 and N 2 O 4 donor sets, respectively. The Schiff base serves as a common N,O'-tridentate ligand in 1, and as a unique O-monodentate ligand in 2. In the crystal, both 1and 2form a 3D supramolecular architecture by O-H···O, C-H···O interactions or π···π stacking. The thermal and solid-state photoluminescence properties of both complexes have been investigated Graphical Abstract Syntheses, Structures, Thermal and Photoluminescence Properties of Two Zn(II) and Cd(II) Coordination Polymers Constructed from Taurine-derived Schiff Base and 4,4’-Bipyridine Ligands

Two new Cd(II) complexes, {[Cd(m-bdc)(tmb)(H 2 O)]·CH 3 OH} n (1) and {[Cd(t-bdc)(tmb)(H 2 O)] ·2H 2 O·DMF} n (2), have been prepared by using 2-((1H-1,2,4-triazol-1-yl)methyl)-1Hbenzimidazole (tmb) as a ligand in the presence of 1,3-benzenedicarboxylic acid (m-H 2 bdc) or 1,4-benzenedicarboxylic acid (t-H 2 bdc). Single-crystal X-ray diffraction exhibits that complex 1 displays a 2D structure constructed by tmb ligands in trans conformation and carboxylate groups in a chelating mode. The 2D structure of complex 2is different from that of 1, in that the tmb ligands are in cis conformation, and the carboxylate groups are in both unidentate or chelating coordination mode at the Cd(II) centers. The luminescence properties of 1and 2in the solid state at room temperature have been studied Graphical Abstract Syntheses, Structures and Luminescence Properties of Two Cd(II) Complexes Based on 2-((1H-1,2,4-Triazol-1-yl)methyl)-1H-benzimidazole and Aromatic Polycarboxylate Ligands

Three flexible α,ѡ-bis(5,6-dimethylbenzimidazolyl)alkane ligands with different spacers were reacted with CdX 2 (X = Cl, Br, I) hydrothermally, resulting in three coordination architectures, namely [CdI 2 (L 1 )] n (1), [CdBr 2 (L 2 )] n (2), and Cd 2 Cl 4 (L 3 ) 2 (3) [L 1 = 1,3-bis(5,6- dimethylbenzimidazole)propane, L 2 = 1,5-bis(5,6-dimethylbenzimidazole)pentane, L 3 = 1,6- bis(5,6-dimethylbenzimidazole)hexane]. They have been characterized by elemental analyses, IR spectra, thermogravimetric (TG) analysis, and single-crystal X-ray diffraction. Complex 1displays a helical chain linked by the ligands L 1 , and a 2D supramolecular network is constructed through π-π stacking interactions; complex 2shows a helical chain structure with connections through two kinds of strong π-π stacking interactions into an intricate 3D supramolecular network; complex 3 contains dinuclear metallomacrocycles. The fluorescence properties of 1-3have been investigated in the solid state Graphical Abstract Assembly of Three Cadmium(II) Complexes Based on Flexible α,ѡ-Bis(benzimidazolyl)alkane Ligands

Two coordination polymers, [Ni(H 2 O)(L)(OBA)] (1) and [Pb(L) 2 (OBA)]·3H 2 O (2) [L=2- (4-fluorophenyl)-1H-imidazo[4,5- f ][1,10]phenanthroline and OBA=4,4’-oxybis(benzoate)], have been synthesized under hydrothermal conditions, and characterized by elemental analysis, and IR and UV=Vis spectra. Crystal data for 1: C 33 H 21 FN 4 NiO 6 , triclinic, space group P1̅, a=13.8490(10), b=14.932(2), c=14.993(3) Å, α =107.534(4), β =94.670(4), γ =103.836(5)°, V =2830.9(7) Å 3 , Z =4. Crystal data for 2: C 52 H 36 F 2 N 8 O 8 Pb, orthorhombic, space group Pna2 1 , a=16.256(4), b=16.085(5), c=17.810(3) Å, V =4657 (2) Å 3 , Z =4. In 1, OBA dianions bridge Ni(II) atoms to form two crystallographically distinct chains. These chains are further extended into a 2D supramolecular architecure through p-p interactions. In 2, each OBA dianion links neighboring Pb(II) atoms to yield a helical chain. Further, π-π interactions among adjacent chains give rise to a 3D supramolecular architecture Graphical Abstract Syntheses, Structures and Characterization of Two Ni(II) and Pb(II) Coordination Polymers Constructed by 2-(4-Fluorophenyl)-1Himidazo[ 4,5-f][1,10]phenanthroline and Flexible 4,4’-Oxybis(benzoate) Ligands

9a A series of linear and macrocyclic pentapeptide derivatives have been prepared via the coupling of pyridine-2,6-dicarboxylic acid (1) or pyridine-2,6-dicarbonyl dichloride (2) with appropriate amino acid methyl esters. The coupling of 1or 2with aminoacid methyl esters gave the corresponding pyridine dipeptide methyl esters 3, which were hydrolyzed with sodium hydroxide to the corresponding acids 4. The latter compounds 4were coupled with other amino acid methyl esters to afford the corresponding tetrapeptide esters 5, which were hydrolyzed with sodium hydroxide to the corresponding acids 6. Cyclization of tetrapeptide acids with L-lysine methyl ester or with aliphatic diamide derivatives afforded the corresponding cyclic pentapeptide methyl ester derivatives 7and cyclic tetrapeptide diamines 8, respectively. Finally, hydrolysis with 1 N sodium hydroxide or hydrazinolysis with hydrazine hydrate of methyl esters 7afforded the corresponding acids - e and hydrazides 10a - e , respectively Graphical Abstract Synthesis and Reactions of New Chiral Linear and Macrocyclic Tetraand Penta-peptide Candidates

A ternary cationic Mn(II) complex with the tripodal ligand tris(2-(N-methyl) benzimidazylmethyl)amine (Mentb), salicylate and DMF as ligands and nitrate as counterion, [Mn(Mentb)(salicylate)DMF](NO 3 ), was synthesized and characterized by physico-chemical and spectroscopic methods. The crystal structure of the Mn(II) complex has been determined by single-crystal X-ray diffraction and revealed that the central Mn(II) atom is seven-coordinated. The DNA-binding properties of the Mn(II) complex were investigated by spectrophotometric methods and viscosity measurements, and the results suggest that the Mn(II) complex binds to DNA via an intercalation binding mode. Additionally, the complex exhibited potential hydroxyl radical scavenge properties in in vitro studies Graphical Abstract Synthesis and DNA-binding Properties of a Cationic Seven-coordinate Manganese(II) Complex Formed with the Tripodal Ligand Tris(Nmethylbenzimidazol- 2-ylmethyl)amine and Salicylate

An 18 F-labeled pyrazolo[1,5-a]pyrimidine derivative, 7-(2-chlorophenylamino)-5-((2-[ 18 F] fluoroethyoxy)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile ([ 18 F]5), has been designed and prepared as a radio tracer candidate for tumor detection with positron emission tomography (PET). The desired product [ 18 F]5was synthesized by nucleophilic substitution of the corresponding tosylated precursor with [ 18 F]KF=Kryptofix 2.2.2 and potassium carbonate in anhydrous DMF at 100 °C for 20 min followed by purification with HPLC. The radiochemical purity was >98%, and the radio-chemical yield was 25% (decay-uncorrected). Compound [ 18 F]5was very stable in vitro. The biodistribution study in mice bearing S180 tumors demonstrated that [ 18 F]5had a rapid and prolonged accumulation in tumors with moderate washout from other tissues Graphical Abstract Synthesis and Biological Evaluation of 7-(2-Chlorophenylamino)-5-((2- [ 18 F]fluoro-ethyoxy)methyl)pyrazolo[1,5-a]pyrimidine-3-carbonitrile as PET Tumor Imaging Agent

Reverse transcriptase enzyme (RT) is an attractive target for the development of new drugs useful in AIDS therapy and HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs), and offers the possibility of generating structures of increased potency. On this basis, a series of 4-oxo-3-phenyl-2- (phenylimino)thiazolidin-5-ylidene, 3-hydroxypropyl, 3-azidopropyl, and 3-aminopropyl derivatives of 1-benzyl-2-ethyl-4-nitroimidazoles 6-8, as well as the substituted 1,2,3-triazolo analogs 12-14, the diazepam 15 and carboxamide derivatives 16 and 17 were synthesized. All compounds have been evaluated for their anti-HIV activity Graphical Abstract Nitroimidazoles Part 7. Synthesis and Anti-HIV Activity of New 4-Nitroimidazole Derivatives

A new coordination polymer {[Zn(BDC-I 4 )- (DMSO) 2 ]·(DMSO) 2 (H 2 O) 4 } n (1) was prepared from the reaction of Zn(II) nitrate with 2,3,5,6-tetraiodo-1,4- benzenedicarboxylic acid (H 2 BDC-I 4 ) in DMSO=water and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1crystallizes in the orthorhombic space group Pnma and shows a zigzag chain coordination structure, which is assembled into a 2D network through weak C-H···O and C-H···π interactions. The thermal and photoluminescence properties of complex 1in the solid state are also reported Graphical Abstract A Zinc(II) Coordination Polymer with Tetraiodoterephthalate: Synthesis, Crystal Structure, and Luminescence

The square-planar structure of the [Cl 2 Pt(alaninate)] - anion was determined by X-ray crystallography. In the crystal structure the packing of the components is dominated by layers of potassium ions Graphical Abstract Molecular and Crystal Structure of Potassium-L-alaninatodichloridoplatinate( II), K[Pt(L-alaO)Cl2]

Tetramethylphosphonium iodide is prepared from calcium phosphide and methyl iodide in methanol/water in good yield Graphical Abstract Ein einfacher Zugang zu Tetramethylphosphoniumiodid / A Simple Access to Tetramethylphosphonium Iodide