Nano–Mn‐[4‐nitrophenyl‐salicylaldimine‐methyl pyranopyrazole]Cl2 as a new nanostructured Schiff base complex and catalyst for the synthesis of hexahydroquinolines

By the reaction of 4‐nitrobenzaldehyde with ethyl acetoacetate, malononitrile and hydrazine hydrate, pyranopyrazole derivative as an active biological compound was synthsized and then reacted with salicylaldehyde and MnCl₂.4H₂O to afford nano‐Mn‐[4‐nitrophenyl‐salicylaldimine‐methyl pyranopyrazole]Cl₂ (nano‐[Mn‐4NSMP]Cl₂) for the first time. The produced Schiff base complex with nanostructured was fully characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric (DTG) and scanning electron microscope (SEM) and used it as an efficient catalyst for the preparation of hexahydroquinolines.     

Synthesis of pyranopyrazoles using nano‐Fe‐[phenylsalicylaldiminemethylpyranopyrazole]Cl2 as a new Schiff base complex and catalyst

By the condensation reaction of benzaldehyde with ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of FeCl₂, a pyranopyrazole derivative was prepared which was then reacted with salicylaldehyde to afford nano‐Fe‐[phenylsalicylaldiminemethylpyranopyrazole]Cl₂ (nano‐[Fe‐PSMP]Cl₂). The prepared nano‐Schiff base complex was fully characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, differential thermogravimetry, scanning electron microscopy and UV–visible spectroscopy, and was used as an efficient and catalyst for the preparation of pyranopyrazoles.     

Dispersion of Reduced Graphene Oxide in Multiple Solvents with an Imidazolium‐Modified Hexa‐peri‐hexabenzocoronene

An imidazolium‐modified hexa‐peri‐hexabenzocoronene derivative (HBC‐C₁₁‐MIM[Cl^?]) was designed and synthesized as a stabilizer to fabricate reduced graphene oxide (RGO). The resulting RGO/HBC‐C₁₁‐MIM[Cl^?] hybrid shows excellent dispersivity (5.0 mg mL^?1) and stability in water. RGO/HBC‐C₁₁‐MIM[Cl^?] was comprehensively characterized by using atomic force microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, thermogravimetric analysis, and Raman spectroscopy, thus revealing that one HBC‐C₁₁‐MIM[Cl^?] group can stabilize about 178 carbon atoms on the graphene sheets. The obtained hybrid film exhibits a high conductivity of 286 S m^?1. Furthermore, the HBC‐C₁₁‐MIM[Cl^?]‐modified RGO sheets can be readily dispersed in polar organic solvents upon exchange of the hydrophilic Cl^? ions for hydrophobic bis(trifluoromethylsulfonyl) amide (NTf₂^?) ions.     

Construction of Three Coordination Compounds Formed by in‐situ Ligand Reaction of 1‐Cyanobenzoimidazole

Solvothermal reactions of 1‐cyanobenzoimidazole, NaN₃, and hydrated M^IICl₂ (M = Mn, Zn, Cu) in a mixture of EtOH/H₂O in the presence of NH₄Cl afforded a mononuclear complex [Mn(L¹)₂(H₂O)₄] ( 1 ), a 3D polymer [Zn(L¹)(OH)]_n ( 2 ), and a linear polymer {[Cu(Bim)]}_n ( 3 ), respectively, where the ligand L¹ is formed in‐situ from [3+2] dipolar cycloaddition of N₃^– with nitrile and the ligand Bim is in‐situ formed from C–N bond cleavage of 1‐cyanobenzoimidazole. (L¹ = 5‐benzoimidazoyltetrazolate, Bim = benzoimidazole). All the compounds were characterized by IR spectroscopy, elemental analysis, and thermo‐gravimetric analysis (TGA), and their structures were determined by X‐ray crystallography. The solid state luminescent properties of 2 and 3 were also investigated at room temperature.     

Reverse Micelle Synthesis of Colloidal Nickel–Manganese Layered Double Hydroxide Nanosheets and Their Pseudocapacitive Properties

Colloidal nanosheets of nickel–manganese layered double hydroxides (LDHs) have been synthesized in high yields through a facile reverse micelle method with xylene as an oil phase and oleylamine as a surfactant. Electron microscopy studies of the product revealed the formation of colloidal nanoplatelets with sizes of 50–150 nm, and X‐ray diffraction, energy dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy studies showed that the Ni–Mn LDH nanosheets had a hydrotalcite‐like structure with a formula of [Ni₃Mn(OH)₈](Cl^?) ? n H₂O. We found that the presence of both Ni and Mn precursors was required for the growth of Ni‐Mn LDH nanosheets. As pseudocapacitors, the Ni–Mn LDH nanosheets exhibited much higher specific capacitance than unitary nickel hydroxides and manganese oxides.     

Synthese und Charakterisierung neuer fünf‐ und sechsfach koordinierter Mangan(II)‐Komplexe als Modellsysteme für manganabhängige Catecholdioxygenasen

Synthesis and Characterization of Novel Five‐ and Six‐coordinate Manganese Complexes as Catechol Dioxygenase Models The five‐ and six‐coordinate manganese complexes [Mn(tphhp)Cl₂] {tphhp = N,N′‐bis(2‐pyridylmethyl)‐2‐(2‐pyridyl)hexahydropyrimidine} ( 1 ), [Mn(bpma)Cl](ClO₄) {bpma = bis((2‐pyridylmethyl)((1‐methylbenzimidazol‐2‐yl)‐methyl)amine} ( 2 ) and [Mn(L)TCC] {HL = (1‐hydroxy‐4‐nitrobenzyl)((1‐methylimidazol‐2‐yl)methyl)(2‐pyridylmethyl)amine} ( 3 ) were synthesized and characterized by various techniques such as single crystal X‐ray structure analysis, mass spectrometry, IR and UV/vis spectroscopy, cyclic voltammetry, and elemental analysis. 1 and 2 crystallize in the monoclinic space group P2₁/n (No. 14) ( 1 ) and P2₁/c (No. 14) ( 2 ). The ligand and the chlorine ions provide the N₃Cl₂‐donorset in 1 and the N₃Cl₂‐donorset in 2 , respectively. Compounds 1 and 2 show catalytic activity regarding the oxidation of 3,5‐di‐tertbutylcatechol to 3,5‐di‐tert‐butylchinon. To our knowledge, 1 and 2 are the first five‐coordinate manganese complexes that show catecholase activity. 3 crystallize in the orthorhombic space group P2₁2₁2₁ (No. 19) and the ligand and tetrachlorocatechol (TCC) build the N₃O₃‐donorset in 3 .     

Assembly,Structures, and Properties of a Series of Metal‐Organic Coordination Polymers Derived from a Semi‐rigid Bis‐pyridyl‐bis‐amide Ligand

Four metal‐organic coordination polymers [Cd(4‐bpcb)_1.5Cl₂(H₂O)] ( 1 ), [Cd(4‐bpcb)_0.5(mip)(H₂O)₂] · 3H₂O ( 2 ), [Co(4‐bpcb)(oba)(H₂O)₂] ( 3 ), and [Ni(4‐bpcb)(oba)(H₂O)₂] ( 4 ) [4‐bpcb = N,N′‐bis(4‐pyridinecarboxamide)‐1, 4‐benzene, H₂mip = 5‐methylisophthalic acid, and H₂oba = 4, 4′‐oxybis(benzoic acid)] were synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, elemental analyses, IR spectroscopy, powder X‐ray diffraction, and TG analysis. In complex 1 , two Cl^– anions serve as bridges to connect two Cd‐(μ₁‐4‐bpcb) subunits forming a dinuclear unit, which are further linked by μ₂‐bridging 4‐bpcb to generate 1D zigzag chain. Complex 2 shows a 2D 6³ network constructed by [Cd‐mip]_n zigzag chains and μ₂‐bridging 4‐bpcb ligands. Complexes 3 and 4 are isostructural 2D (4, 4) grid networks derived from [M‐oba]_n (M = Co, Ni) zigzag chains and [M‐(4‐bpcb)]_n linear chains. The 1D chains for 1 and the 2D networks for 2 – 4 are finally extended into 3D supramolecular architectures by hydrogen bonding interactions. The roles of dicarboxylates and central metal ions on the assembly and structures of the target compounds were discussed. Moreover, the thermal stabilities, photoluminescent properties, and photocatalytic activities of complexes 1 – 4 and the electrochemical properties of complexes 3 and 4 were investigated.     

Synthesis and Structural Characterization of Metal Complexes of 2‐Formylpyrrole‐4N‐ethylthiosemicarbazone (4 EL1) and 2‐Acetylpyrrole‐4N‐ethylthiosemicarbazone (4 EL2)

The reactions of ⁴N‐ethyl‐2‐[1‐(pyrrol‐2‐yl)methylidene(hydrazine carbothioamide ( 4 EL₁ ) and ⁴N‐ethyl‐2[1‐(pyrrol‐2‐yl)ethylidene(hydrazine carbothioamide ( 4 EL₂ ) with Group 12 metal halides afforded complexes of types [M(L)₂X₂] (M = Zn, Cd; L = 4 EL₁, 4 EL₂; X = Cl, Br, I; 1 – 6 , 14 – 19 ) and [M(L)X₂] (M = Hg; L = 4 EL₁, 4 EL₂; X = Cl, Br, I; 7 – 9 , 20 – 22 ). In addition, reaction of 4 EL₁ with salts of Cu^II, Ni^II, Pd^II and Pt^II afforded compounds of type [M(4 EL₁–H)₂] ( 10 – 13 ). The new compounds were characterized by elemental analysis, FAB mass spectrometry, IR and electronic spectroscopy and, for sufficiently soluble compounds, ¹H, ¹³C and, when appropriate, ¹¹³Cd or ¹⁹⁹Hg NMR spectrometry. The spectral data suggest that in their complexes with Group 12 metal cations, both thiosemicarbazones are neutral and S‐monodentate; and for [Zn(4 EL₁)₂I₂] ( 3 ), [Cd(4 EL₁)₂Br₂] ( 5 ) and [Hg(4 EL₁)Cl₂]₂ ( 7 ) this was confirmed by X‐ray diffractometry. By contrast, in its complexes with Cu^II and Group 10 metal cations, 4 EL₁ is monodeprotonated and S,N‐bidentate, as was confirmed by X‐ray diffractometry for [Ni(4 EL₁–H)₂] ( 11 ) and [Pd(4 EL₁–H)₂] ( 12 ).     

Three Coordination Polymers based on 3,5‐Bis(imidazole‐1‐yl)pyridine and Benzoic Acid: Synthesis,Crystal Structures and Photoluminescent Properties

Three metal coordination polymers {[Co(L)₂(H₂O)₂]²⁺ · 2NO₃^–}_n ( 1 ), {[Mn(L)₂(H₂O)₂]²⁺ · 2Cl^– · 3H₂O}_n ( 2 ), and [ZnL(ba)₂]_n ( 3 ) [L = 3,5‐bis(imidazole‐1‐yl)pyridine and Hba = benzoic acid] were synthesized and structurally characterized by IR spectroscopy, elemental analysis, X‐ray powder diffraction, and X‐ray single crystal diffraction. Complex 1 shows a one‐dimensional (1D) chain structure. Adjacent chains are connected by hydrogen bonding and nitrate groups to form a 3D network. Complex 2 features a 2D layer structure. A three‐dimensional network is constructed through the cluster consisting of two chloride ions and three water molecules. Complex 3 shows a 1D zigzag chain structure that further twists together to form a 3D network. The X‐ray powder diffraction patterns were compared with the simulated ones. Moreover, the luminescent properties of 1 – 3 were investigated in the solid state at room temperature, and the thermogravimetric analyses were carried out to study the thermal stability of the three complexes.     

Engineering a Cu‐MOF Nano‐Catalyst by using Post‐Synthetic Modification for the Preparation of 5‐Substituted 1H‐Tetrazoles

A new nano scale Cu‐MOF has been obtained via post‐synthetic metalation by immersing a Zn‐MOF as a template in DMF solutions of copper(II) salts. The Cu‐MOF serves as recyclable nano‐catalyst for the preparation of 5‐substituted 1H‐tetrazoles via [3 + 2] cycloaddition reaction of various nitriles and sodium azide in a green medium (PEG). The post‐synthetic metalated MOF were characterized by FT‐IR spectroscopy, powder X‐ray diffraction (PXRD), atomic absorption spectroscopy (AAS), and energy dispersive X‐ray spectroscopy (EDX) techniques. The morphology and size of the nano‐catalyst were determined by field emission scanning electron microscopy (FE‐SEM).     

Synthesis,Crystal Structure,and DNA‐Binding Properties of a New Cd(II) Complex Involving 2‐(2‐1H‐Imidazolyl)‐1H‐Imdazolium Ligand

A new Cd(II) complex of Cd(H₃biim)₂(NCS)₂Cl₂ [H₃biim=2‐(2‐1H‐imidazolyl)‐1H‐imidazolium] was synthesized and characterized by elemental analyses, FT‐IR and X‐ray single crystal diffraction. In the X‐ray crystallography structure, the cadmium(II) ion is coordinated by two nitrogen atoms of two 2‐(2‐1H‐imidazolyl)‐ 1H‐imdazolium, two nitrogen atoms of two thiocyanate ions and two Cl^?. The interaction of the complex with calf thymus DNA was investigated through electronic absorption spectroscopy, fluorescence spectroscopy, viscosity measurement, cyclic voltammetry and gel electrophoresis. These results show that the Cd(II) complex can electrostatically bind to the phosphate group of DNA backbone. Interestingly, we found that the complex can cleave the pBR322 DNA at pH=7.2 and 37°C.     

Nimustine hydrochloride: the first crystal structure determination of a 2‐chloroethyl‐N‐nitrosourea hydrochloride derivative by X‐ray powder diffraction and solid‐state NMR

Nimustine hydrochloride [systematic name: 4‐amino‐5‐({[N‐(2‐chloroethyl)‐N‐nitrosocarbamoyl]amino}methyl)‐2‐methylpyrimidin‐1‐ium chloride], C₉H₁₄ClN₆O₂⁺·Cl⁻, is a prodrug of CENU (chloroethylnitrosourea) and is used as a cytostatic agent in cancer therapy. Its crystal structure was determined from laboratory X‐ray powder diffraction data. The protonation at an N atom of the pyrimidine ring was established by solid‐state NMR spectroscopy.     

Diethyldisulfoammonium chlorometallates as heterogeneous Brønsted–Lewis acidic catalysts for one‐pot synthesis of 14‐aryl‐7‐(N‐phenyl)‐14H‐dibenzo[a,j]acridines

A new series of Brønsted–Lewis acidic diethyldisulfoammonium chlorometallates, [DEDSA][FeCl₄] and [DEDSA]₂[Zn₂Cl₆], were synthesized as solid materials from the reaction of [(Et)₂N(SO₃H)₂][Cl] ionic liquid with transition metal chlorides (FeCl₃ and ZnCl₂) at 80 °C in neat condition for 2 h. The chlorometallates were fully characterized using various spectroscopic and analytical techniques such as Fourier transform infrared, UV–visible and Raman spectroscopies, powder X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray and thermogravimetric analyses, Hammett acidity and elemental analyses. Their catalytic activity was studied as reusable heterogeneous catalysts for the three‐component synthesis of novel 14‐aryl‐7‐(N‐phenyl)‐14H‐dibenzo[a,j]acridines under solvent‐free conditions at 100 °C.     

Mn(III)–pentadentate Schiff base complex supported on multi‐walled carbon nanotubes as a green,mild and heterogeneous catalyst for the synthesis of tetrahydrobenzo[b]pyrans via tandem Knoevenagel–Michael cyclocondensation reaction

Mn(III)–pentadentate Schiff base complex supported on multi‐walled carbon nanotubes as a recyclable and reusable, green and nano‐heterogeneous catalyst was designed and fully characterized using infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy , inductively coupled plasma mass spectrometry, elemental analysis and thermogravimetric analysis. A facile, eco‐friendly, mild and green procedure was developed for the one‐pot three‐component synthesis of tetrahydrobenzo[b ]pyrans via tandem Knoevenagel–Michael cyclocondensation reactions between aromatic aldehydes, 1,3‐diones and malononitrile using a catalytic amount of Mn(III)–pentadentate Schiff base complex supported on MWCNTs as an efficient recyclable heterogeneous catalyst under solvent‐free conditions at room temperature. This process has the advantages of easy availability, stability, recyclability and eco‐friendliness of the catalyst, short reaction times, high to excellent yields and simple work‐up procedure.     

Synthesis of 4‐((2‐hydroxynaphthalen‐1‐yl)(aryl)methyl)‐5‐methyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐ones using nano‐Zn‐[2‐boromophenyl‐salicylaldimine‐methylpyranopyrazole]Cl2 nanoparticles

Nano‐Zn‐[2‐boromophenyl‐salicylaldimine‐methylpyranopyrazole]Cl₂ (nano‐[Zn‐2BSMP]Cl₂) as a nanoparticle Schiff base complex and a catalyst was introduced for the solvent‐free synthesis of 4‐((2‐hydroxynaphthalen‐1‐yl)(aryl)methyl)‐5‐methyl‐2‐phenyl‐1H‐pyrazol‐3(2H)‐ones by the multicomponent condensation reaction of various aromatic aldehydes, β‐naphthol, ethyl acetoacetate, and phenyl hydrazine at room temperature.     

Preparation,Structural Characterization,and Antifungal Activities of Complexes of Group 12 Metals with 2‐Acetylpyridine‐ and 2‐Acetylpyridine‐N‐oxide‐4N‐phenylthiosemicarbazones

Reaction of group 12 metal dihalides in ethanolic media with 2‐acetylpyridine ⁴N‐phenylthiosemicarbazone ( H4PL ) and 2‐acetylpyridine‐N‐oxide ⁴N‐phenylthiosemicarbazone ( H4PLO ) afforded the compounds [M(H4PL)X₂] (X = Cl, Br, M = Zn, Cd, Hg; X = I, M = Zn, Cd) ( 1–8 ), [Hg(4PL)I]₂ ( 9 ) and [M(H4PLO)X₂] (X = Cl, Br, I, M = Zn, Cd, Hg) ( 10–18 ). H4PL , H4PLO and their complexes were characterized by elemental analysis and by IR and ¹H and ¹³C NMR spectroscopy (and the cadmium complexes by ¹¹³Cd NMR spectroscopy), and H4PL , H4PLO , ( 5 · DMSO) and ( 9 ) were additionally studied by X‐ray diffraction. H4PL is N,N,S‐tridentate in all its complexes, including 9 , in which it is deprotonated, and H4PLO is in all cases O,N,S‐tridentate. In all the complexes, the metal atoms are pentacoordinate and the coordination polyhedra are redistorted tetragonal pyramids. In assays of antifungal activity against Aspergillus niger and Paecilomyces variotii, the only compound to show any activity was [Hg(H4PLO)I₂] ( 18 ).     

The crystal structure,luminescence and nitrobenzene‐sensing properties of a two‐dimensional MnII coordination polymer based on 2,6‐bis(imidazol‐1‐yl)pyridine

A two‐dimensional Mn^II coordination polymer (CP), poly[bis[μ₂‐2,6‐bis(imidazol‐1‐yl)pyridine‐κ²N³:N^3′]bis(thiocyanato‐κN)manganese] [Mn(NCS)₂(C₁₁H₉N₅)₂]_n, (I), has been obtained by the self‐assembly reaction of Mn(ClO₄)₂·6H₂O, NH₄SCN and bent 2,6‐bis(imidazol‐1‐yl)pyridine (2,6‐bip). CP (I) was characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. The crystal structure features a unique two‐dimensional (4,4) network with one‐dimensional channels. The luminescence and nitrobenzene‐sensing properties were explored in a DMF suspension, revealing that CP (I) shows a strong luminescence emission and is highly sensitive for nitrobenzene detection.     

Two novel organic–inorganic hybrid materials from tetrachloridometallate(II) salts and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium

Two organic–inorganic hybrid compounds have been prepared by the combination of the 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium cation with perhalometallate anions to give 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridocobaltate(II), (C₁₂H₁₂N₂)[CoCl₄], (I), and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridozincate(II), (C₁₂H₁₂N₂)[ZnCl₄], (II). The compounds have been structurally characterized by single‐crystal X‐ray diffraction analysis, showing the formation of a three‐dimensional network through X—H...Cl_nM⁻ (X = C, N⁺; n = 1, 2; M = Co^II, Zn^II) hydrogen‐bonding interactions and π–π stacking interactions. The title compounds were also characterized by FT–IR spectroscopy and thermogravimetric analysis (TGA).     

pH Dependent Synthesis of Two Manganese Compounds based on 5‐(2‐Pyrimidyl)tetrazole‐1‐acetic Acid

Reactions of Hpymtza [Hpymtza = 5‐(2‐pyrimidyl)tetrazole‐1‐acetic acid] with MnCl₂ · 4H₂O under different pH conditions, afforded the complexes [Mn(pymtza)₂(H₂O)₄] ( 1 ) and [Mn₂(pymtza)₂Cl₂(EtOH)] · H₂O ( 2 ). The compounds were structurally characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. Compound 1 shows a mononuclear structure, whereas complex 2 has a 1D chain structure. In compound 1 , the pymtza ligand only acts in a monodentate manner to coordinate to one central Mn^II atom by one carboxylate atom, In 2 , pymtza acts as tetradentate ligand to connect three Mn^II ions. Compounds 1 and 2 display 3D networks by hydrogen bonding interactions. Furthermore, the luminescence properties of Hpymtza as well as compounds 1 and 2 were investigated at room temperature in the solid state.     

Counterion‐Directed Assembly of Praseodymium(III) Compounds based on the Flexible Ligand 5‐Aminotetrazole‐1‐propionic Acid (Hatzp)

Different kinds of counterions (such as NO₃^–, ClO₄^–, and Cl^–) play a special role in controlling the framework of coordination compounds. Using this strategy, 5‐aminotetrazole‐1‐propionic acid (Hatzp) was selected to react with praseodymium(III) nitrate or perchlorate in the same solvent system, producing two different coordination compounds, [Pr₂(atzp)₄(H₂O)₈] · 2NO₃ · 2H₂O ( 1 ) and [Pr₂(atzp)₆(H₂O)₂] · H₂O ( 2 ). These compounds were structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. X‐ray diffraction analysis revealed that compound 1 displays a dinuclear structure, whereas 2 shows a one dimensional zigzag chain framework. Furthermore, the luminescence properties of compounds 1 and 2 were investigated at room temperature in the solid state.