Fused quinoline heterocycles VI: Synthesis of 5H‐1‐thia‐3,5,6‐triazaaceanthrylenes and 5H‐1‐thia‐3,4,5,6‐tetraazaaceanthrylenes

Ethyl 3‐amino‐4‐chlorothieno[3,2‐c]quinoline‐2‐carboxylate ( 4 ) is a versatile synthon, prepared by reacting an equimolar amount of 2,4‐dichloroquinoline‐3‐carbonitrile ( 1 ) with ethyl mercaptoacetate ( 2 ). Ethyl 5‐alkyl‐5H‐1‐thia‐3,5,6‐triazaaceanfhrylene‐2‐carboxylates 9a‐c , novel perianellated tetracyclic heteroaro‐matics, were prepared by refluxing 4 with excess of primary amines 7a‐c to yield the corresponding amino‐thieno[3,2‐c]quinolines 8a‐c . Subsequent reaction with an excess of triethyl orthoformate (TEO) furnished 9a‐c . Reaction of 4 with TEO in Ac₂O at reflux, gave the simple acetylated compounds, thieno[3,2‐c]‐quinolines 12 and 13 . Refluxing 4 with benzylamine ( 7d ) gave 10 , and subsequent treatment with TEO gave the tetracyclic compound 11 . Refluxing 13 with an excess of alkylamines 7a‐d gave the fhieno[3,2‐c]quino‐lines 15 . Refluxing the aminothienoquinolines 8b with an excess of triethyl orthoacetate gave thieno[3,2‐c]quinoline 17 , while heating with Ac₂O gave 18 and 19 , with small amounts of 16 . Reaction of 8a,b with ethyl chloroformate and phenylisothiocyanate generated the new 1‐thia‐3,5,6‐triazaaceanthrylenes 20a,b and 21a,b , respectively. Diazotization of 8a‐c afforded the novel tetracyclic ethyl 5‐alkyl‐5H‐1‐fhia‐3,4,5,6‐tetraazaaceanthrylene‐2‐carboxylates 22a‐c in good yields.     

Syntheses and Crystal Structures of Cadmium Complexes with Thiophenedicarboxylate and Bipyridine‐like Ligands

Two new coordination polymers [Cd(tdc)(bpy)(H₂O)]_n ( 1 ) and [Cd(tdc)(phen)]_n ( 2 ) (H₂tdc = thiophene‐2,5‐dicarboxylic acid, bpy = 2,2′‐bipyridine and phen = 1,10‐phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X‐ray single‐crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) Å, V = 7044(6) ų, Z = 16; 2 in the monoclinic space group P2₁/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) Å, β = 105.01(1)°, V = 1548.8(2) ų, Z = 4. Both of them are double‐stranded chains and further assembled into three‐dimensional networks by π‐π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.     

Synthesis, Characterization and Two-Photon Absorption Properties of a Novel Pyridinium Salt

A novel pyridinium salt, 2,4-bis[p-(N,N-dimethylamino)styryll-N-metlayl pyridinium iodide (BMSPI) was synthesized and characterized by TG, ^1H NMR spectroscopy and elemental analysis, and the reaction process was studied by using ES-MS. When BMSPI was pumped by a pulsed 1064 nm, 50 ps laser beam, it manifests highly efficient TPA (Two-Photon Absorption) and up-conversion superradiance. The up-conversion efficiency was 6.0% at the pump energy of 4-6 mJ and the lifetime of two-photon fluorescence was measured as 59 ps.     

Preparation and characterization of lithium ion-conducting glass-ceramics in the Li1 + xCrxGe2 − x(PO4)3 system

Li₂O–Cr₂O₃–GeO₂–P₂O₅ based glasses were synthesized by a conventional melt-quenching method and successfully converted into glass-ceramics through heat treatment. Experimental results of DTA, XRD, ac impedance techniques and FESEM indicated that Li_1.4Cr_0.4Ge_1.6(PO₄)₃ glass-ceramics treated at 900 °C for 12 h in the Li_1 + xCr_xGe_2 − x(PO₄)₃ (x = 0–0.8) system exhibited the best glass stability against crystallization and the highest ambient conductivity value of 6.81 × 10⁻⁴ S/cm with an activation energy as low as 26.9 kJ/mol. In addition, the Li_1.4Cr_0.4Ge_1.6(PO₄)₃ glass-ceramics displayed good chemical stability against lithium metal at room temperature. The good thermal and chemical stability, excellent conducting property, easy preparation and low cost make it promising to be used as solid-state electrolytes for all-solid-state lithium batteries.     

Kinetics and mechanism of oxidation of a ternary complex involving dipicolinatochromium(III) and DL‐aspartic acid by N‐bromosuccinimide

The kinetics of oxidation of [Cr^III(Dpc)(Asp)(H₂O)₂] (Dpc = dipicolinic acid and Asp = DL ‐aspartic acid) by N‐bromosuccinimide (NBS) in aqueous solution have been found to obey the equation: where k₂ is the rate constant for the electron transfer process, K₁ is the equilibrium constant for deprotonation of [Cr^III(Dpc)(Asp)(H₂O)₂], K₂ and K₃ are the pre‐equilibrium formation constants of precursor complexes [Cr^III(Dpc)(Asp)(H₂O)(NBS)] and [Cr^III(Dpc)(Asp)(H₂O)(OH)(NBS)]^?. Values of k₂ = 4.85 × 10^?2 s^?1, K₁ = 1.85 × 10^?7 mol dm^?3, and K₂ = 78.2 mol^?1 dm³ have been obtained at 30°C and I = 0.1 mol dm^?3. The experimental rate law is consistent with a mechanism in which the deprotonated [Cr^III(Dpc)(Asp)(H₂O)(OH)]^? is considered to be the most reactive species compared to its conjugate acid. It is assumed that electron transfer takes place via an inner‐sphere mechanism. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 394–400, 2004     

A Novel 3‐D Heterobimetallic Cyano‐bridged Coordination Polymer Incorporating Ag···Ag Interaction: [Cu(dien)Ag(CN)2]2[Ag2(CN)3][Ag(CN)2]

A three‐dimensional cyano‐bridged copper(II) complex, [Cu(dien)Ag(CN)₂]₂[Ag₂(CN)₃][Ag(CN)₂] ( 1 ) (dien = diethylenetriamine), has been prepared and characterized by X‐ray crystallography. Complex 1 crystallized in the monoclinic space group P2₁/n with a = 6.988(2), b = 17.615(6), c = 12.564(4) Å, β = 90.790(5)°. The crystal consists of cis‐[Cu(dien)]²⁺ units bridged by [Ag(CN)₂]^— to form a zig‐zag chain. The Ag atoms of the free and bridging [Ag(CN)₂]^— link together to form additional infinite zig‐zag chains with short Ag···Ag distances. The presence of Ag···Ag interactions effectively increases the dimensionality from a 1‐D chain to a 3‐D coordination polymer.     

Towards Single-component Molecular Conductor [Ni(dmit)_2] by Charge Disproportionation:2[Ni(dmit)_2]~(-0.5)[Ni(dmit)_2]+[Ni(dmit)_2]~-

It was commonly thought that a molecular conductor or semiconductor should be composed of at least two components to make the conducting component in partially charged state. However, this idea became questionable by the recent report of the single-component molecular conductor [Ni(tmdt)2]1 as well as several reports about single-component molecular semiconductors such as [Ni(ptdt)2]2 and [Ni(C10H10S8)2]3. In fact, as early as 1985, [Ni(dmit)2] as a by-product in synthesizing TTF[Ni(dmit…     

A Novel Fluorescent Aminoacid Designed for Fluorometric Detection of Cu （Ⅱ）

A fluorescent aminoacid was designed for selective and sensitive detection of Cu(II) in aqueous solution. The designing of this Cu(II) fluorescent chemosensing molecule, N ± (1‐naphthyl). aminoacetic acid (NAA), was based on the binding of Cu(II) to aminoacetic acid and the novel charge transfer photophysics of 1‐aminonaphthalenes. The fluorescence of NAA was found quenched by Cu (II) and several other metal ions of similar electronic structure such as Co(II), Ni(II) and Zn(II). The quenching was shown to occur via electron transfer within the metal‐NAA complex, which required an optimal combination of high binding affinity and favorable redox properties of the components in the metal‐NAA complex and hence afforded selective fluorometric detection of Cu(II). The calibration graph obeyed Stern‐Volmer theory and was shown for Cu(II) over the range of 0–2.75 ± 10–⁴ mol/L. The quenching constant of Cu(II) was measured as 8.0 ± 10³ mol/L that was two orders of magnitude higher than those of Co(II), Ni(II) and Zn(II). The 3SD limit of detection for Cu(II) was 8.00 ± 10^?6 mol/L with a coefficient of variation of 1.65%. Linear range for quantitative detection of Cu(II) was 2.67 ± 10^?5‐2.75 ± 10^?4 mol/L. The method was applied to synthetic sample measurements which gave recoveries of 105%‐112%.     

Anion and Additive Effects on the Structure of Mercury(II) Halides Complexes with Tripodal Ligand

The metal complexes [Hg₂(tbim)₂Br₄]·2DMF ( 1 ) and [Hg₂(tbim)I₄]·1.5DMF ( 2 ) were prepared by reactions of 1,3,5‐tris(benzimidazol‐1‐ylmethyl)‐2,4,6‐trimethylbenzene (tbim) with HgBr₂, HgI₂, respectively, and [Hg₂(tbim)I₄]·0.5(FeCp₂)·H₂O ( 3 ) was obtained by the same method with addition of ferrocene (FeCp₂) as additive. Their structures were determined by X‐ray crystallographic analyses. Complex 1 has a macrocyclic binuclear structure with one benzimidazole arm of the ligand free of coordination and the binuclear units are further connected by C‐H···N hydrogen bonds to give an infinite zigzag chain. Complexes 2 and 3 have a 2D network structure in which tbim serves as a tridentate ligand. The results showed that the halides of bromide and iodide have remarkable impact on the structure of the complexes. The FeCp₂ molecules are trapped in the voids of framework 3 .     

Inside Cover: From Reactivity and Regioselectivity to Stereoselectivity: An Odyssey of Designing PIP Amine and Related Directing Groups for C—H Activation (Chin. J. Chem. 7/2019)

The inside cover picture shows the journey of developing PIP amine directing group for C—H activation, from controlling the reactivity and diastereoselectivity to enantioselectivity. In the presence of Pd or base metal catalysts, PIP amine enabled the activation of inert C—H bonds to form diverse C—C and C—heteroatom bonds. Its tuneable structure has triggered the design of chiral auxiliaries for diastereoselective C—H activation. More recently, enantioselective activation of unbiased methylene C—H bonds has been achieved by cooperative effects between PIP amine and axial chiral ligands. More details are discussed in the article by Shi et al. on page 647–656.