Mesomeric Effects of Graphene Modified with Diazonium Salts: Substituent Type and Position Influence its Properties

In the last decade, graphene and graphene derivatives have become some of the most intensively studied materials. Tuning of the electronic and electrochemical properties of graphene is of paramount importance. In this study, six diazonium‐modified graphenes containing different functional groups according to the diazonium salt precursor were investigated. These diazonium moieties have a strong mesomeric (resonance) effect and act as either electron‐donating or ‐withdrawing species. Different graphene precursors, such as thermally and chemically reduced graphenes were studied. All the products were characterized in detail by elemental combustion analysis, FTIR spectroscopy, Raman spectroscopy, high‐resolution X‐ray photoelectron spectroscopy (XPS), and cyclic voltammetry. Resistivity and zeta potential measurements were consistent with theoretical (DFT) calculations. The results show that chemical modification of graphene by diazotation strongly influences its properties, creating a huge application potential in microelectronics, energy storage and conversion devices, and electrocatalysis.     

Study of some reactions of acridine orange

The nitration and formylation of acridine orange were studied, and its dinitro derivatives and mono and diformyl derivatives were obtained. By measurement of the ionization constants of the conjugated cations and PMR spectroscopy it was proved that the protons attached to C₍₄₎ and C₍₅₎ are substituted.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 213–215, February, 1972.     

吖啶类衍生物的合成研究进展

吖啶类衍生物具有良好的生物活性,在生物制药,功能材料和荧光标记物等领域有重要应用,但合成难度较大。综述了通过催化剂活化酰基的成环反应(分子内成环反应和分子间成环反应)合成吖啶衍生物的方法,并对其未来的发展进行了展望。参考文献19篇。     

Studies on the n-oxides of π-deficient n-heteroaromatics—XXX: Photochemistry of acridine 10-oxides (2):2 synthesis and reaction of dibenz[c,f]-1,2-oxazepines

The dibenz[c,f]-1,2-oxazepines IId and IIe were obtained as the major products from 9-cyano- and 9-chloroacridine 10-oxides (1d and 1e) by irradiation (?300 nm) in benzene, and found to undergo a variety of isomerization reactions under mild conditions in the dark. Existence of the same species (IIa-IIc) in the irradiated solution of acridine 10-oxide (1a) and its methylated derivatives (1b and 1c) was also confirmed by UV spectroscopy as well as by some trapping experiments.The direct isolation of IId and IIe not only constitutes the first synthesis of 1,2-oxazepine derivatives but also gives experimental support to the previously suggested mechanism (Chart 1) for the photolyses of acridine 10-oxides and the related N-oxides.     

Pulsed laser ablated zeolite nanoparticles: A novel nano-catalyst for the synthesis of 1,8-dioxo-octahydroxanthene and N-aryl-1,8-dioxodecahydroacridine with molecular docking validation

There is an increasing interest in the synthesis of metal nanoparticles (NPs) from bulk metals using pulsed laser ablation in liquids (PLAL), as it offers an easy and simple synthesis route. In this work, zeolite NPs (molecular sieve 4A) were successfully synthesized by the PLAL technique, and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. Data obtained confirm the formation of the crystalline phase of zeolite. The synthesized catalyst (zeolite molecular sieve 4A) was used as an efficient and facile promotor for the synthesis of xanthene and acridine derivatives. Molecular docking of the synthesized compounds was validated using quinone reductase 2 (NQO2) and acridine orange as the ligand, with the synthesized molecules showing good drug–ligand interaction on the active site of NQO2, compared with that of acridine orange.     

endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2-carboxylic acid, a superior resolving agent for the high-performance liquid chromatographic separation of enantiomers of hydroxylated derivatives of two azaaromatic hydrocarbons

The high-performance liquid chromatographic (HPLC) separation of enantiomers of oxide and hydroxy derivatives of dibenz[a,j]acridine and 7-methylbenz[c]acridine was investigated on a chiral stationary phase chromatography column using commercially available columns. In most cases either poor or no separation of enantiomers was achieved. Normal-phase separation of diastereoisomeric ester derivatives of the hydroxy compounds, prepared from commercially available (-)-menthoxyacetic acid or (+)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetic acid, was investigated. No separation of the diastereoisomeric esters of trans-3,4-dihydroxy-3,4-dihydrodibenz[a,j]acridine was observed. However, diastereoisomeric esters prepared from (+)-endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene-2-carboxyl ic acid [(+)-HCA] were easily separated. Using the three chiral acids, diastereoisomers were prepared from sixteen hydroxy derivatives of dibenz[a,j]acridine and 7-methylbenz[c]acridine. (+)-HCA esters gave good to excellent HPLC separations which were superior to those achieved using other chiral acids in most cases. The enantiomeric composition of trans-3,4-dihydroxy-3,4-dihydrodibenz[a,j]acridine formed as a major rodent liver microsomal metabolite of dibenz[a,j]acridine was determined using (+)-HCA.     

A green and efficient procedure for one-pot synthesis of xanthenes and acridines using silica boron–sulfuric acid nanoparticles (SBSANs) as a solid Lewis-protic acid

Silica boron–sulfuric acid nanoparticles (SBSANs) as a solid Lewis-protic acid have been found to be an efficient heterogeneous catalyst in the synthesis of xanthene and acridine derivatives. The SBSAN-catalyzed reaction between carbonyl compound (aldehyde/ketone/ethyl orthoformate) and 5,5-dimethyl-1,3-cyclohexanedione (dimedone) for synthesis of xanthene derivatives is performed under mild conditions with the excellent isolated yield. Also, we can apply a broad scope of carbonyl compounds and amines for efficient synthesis of various acridine derivatives in the presence of SBSAN catalyst. In these multicomponent approaches the SBSAN catalyst can be reused for several times without any treatment in its catalytic activity.     

Synthesis of Some amino-4,5-dihydropyrazolo[3,4-a]acridines as potential cholinesterase inhibitors

A synthesis of the 4,5-dihydro derivatives of the previously known pyrazolo[3,4-a]acridine ring system is described. The reaction of a 3,4-dihydroacridin-1(2H)-one with N,N-dimethylformamide dimethyl acetal gave a reactive enamino ketone, which yielded the desired heterocycle upon reaction with hydrazine. Using this chemistry, 11-amino-4,5-dihydro-2H-pyrazolo[3,4-a)acridine ( 3 ) and a number of its 2-substituted derivatives 4a-k were synthesized and evaluated as acetylcholinesterase inhibitors, based on their relationship to 1,2,3,4-tetrahydro-9-acridinamine (THA). 1-Amino-4,5-dihydro-1H-pyrazolo[3,4-a]acridine ( 11a ) and 2-amino-4,5-dihydro-1H-pyrazolo[3,4-a]acridine ( 11b ) were also synthesized and investigated as potential cholinesterase inhibitors.     

拉曼光谱表征石墨烯材料的研究进展

石墨烯独特的二元化电子价键结构使其在纳米电子器件中具有良好的应用发展前景。拉曼光谱作为一种灵敏、便捷的技术,已被成功地用作表征石墨烯的结构和特性。本综述着重对沉积在不同基底以及掺杂的石墨烯拉曼光谱研究做了一个简单的总结。通过对铟锡氧化物、蓝宝石和玻璃基底上的石墨烯拉曼光谱进行观察,发现在不同基底上的石墨烯拉曼G峰与2D峰峰值会有不同程度的偏移,但2D峰峰值可判断石墨烯层数这一结论仍适用。掺杂可改变石墨烯的荷电状态,使石墨烯表现出空穴（p）型或电子（n）型掺杂特性,通过石墨烯拉曼光谱的变化可以定性石墨烯的掺杂类别并定量表征石墨烯的载流子浓度。     

Amperometric enzyme electrodes for the determination of volatile alcohols in the headspace above fruit and vegetable juices

The surface of a glassy carbon electrode (GCE) was modified by electropolymerization of acridine red followed by drop-coating of graphene. The morphology was characterized by scanning electron microscopy. Uric acid (UA) is effectively accumulated on the surface of the modified electrode and generates a sensitive anodic peak in solutions of pH 6.5. Differential pulse voltammetry was used to evaluate the electrochemical response of the modified GCE to UA. Compared to the bare GCE, the GCE modified with acridine red, and to the graphene modified electrode, the new GCE displays high electrochemical activity in giving an oxidation peak current that is proportional to the concentration of UA in the range from 0.8 to 150?μM, with a detection limit of 0.3?μM (at an S/N of 3). The modified electrode displays excellent selectivity, sensitivity, and a wide linear range. It has been applied to the determination of UA in real samples with satisfactory results.

Negative ion photoelectron spectroscopy of acridine molecular anion and its monohydrate

Negative ion photoelectron spectroscopy was employed to investigate the electronic structure of the acridine molecular anion and its monohydrated anion in the gas phase. Their adiabatic electron affinities were measured to be 0.896+/-0.010 and 1.18+/-0.05 eV, and the low-lying electronic excited states in both neutral acridine and in its monohydrate were revealed. The photoelectron spectra clearly exhibit the presence of low-lying singlet and triplet states having a (pi,pi*) configuration in an uncomplexed acridine molecule. Comparison of the photoelectron spectrum of acridine with that of anthracene shows that photodetachment processes into the excited states of (n,pi*) configuration have little intensity, implying a relatively large intramolecular structural relaxation in the (n,pi*) states.     

The reaction of vinyl ethers with acridine

The reaction of vinyl ethers with acridine gives new acridine derivatives in the presence of an organic ammonium salt and alcohol. An organic ammonium salt such as acridinium chloride affect this reaction. All of the addition products were obtained as dihydroacridinyl derivatives. Moreover, in the reaction of ketene silyl acetal with acridine, the addition products were also obtained as the dihydroacridine derivatives.     

Redesigning the DNA‐Targeted Chromophore in Platinum–Acridine Anticancer Agents: A Structure–Activity Relationship Study

Platinum–acridine hybrid agents show low‐nanomolar potency in chemoresistant non‐small cell lung cancer (NSCLC), but high systemic toxicity in vivo. To reduce the promiscuous genotoxicity of these agents and improve their pharmacological properties, a modular build–click–screen approach was used to evaluate a small library of twenty hybrid agents containing truncated and extended chromophores of varying basicities. Selected derivatives were resynthesized and tested in five NSCLC cell lines representing large cell, squamous cell, and adenocarcinomas. 7‐Aminobenz[c]acridine was identified as a promising scaffold in a hybrid agent ( P1–B1 ) that maintained submicromolar activity in several of the DNA‐repair proficient and p53‐mutant cancer models, while showing improved tolerability in mice by 32‐fold compared to the parent platinum–acridine ( P1–A1 ). The distribution and DNA/RNA adduct levels produced by the acridine‐ and benz[c]acridine‐based analogues in NCI‐H460 cells (confocal microscopy, ICP‐MS), and their ability to bind G‐quadruplex forming DNA sequences (CD spectroscopy, HR‐ESMS) were studied. P1–B1 emerges as a less genotoxic, more tolerable, and potentially more target‐selective hybrid agent than P1–A1 .     

石墨烯纳米载药体系的制备及对人口腔鳞癌细胞杀伤效果

利用化学氧化还原法制备了氧化石墨烯,进一步超声破碎剥离,得到纳米氧化石墨烯,并对其进行聚乙二醇(PEG)的功能化修饰后载药顺铂。 采用扫描电子显微镜(SEM)、紫外-可见吸收光谱(UV-Vis)、傅立叶变换红外光谱(FTIR)对石墨烯纳米载药体系进行表征,细胞存活率实验(MTT)法检验石墨烯纳米载药体系对人口腔鳞癌(KB)细胞的杀伤作用。 结果表明,石墨烯纳米载药体系对顺铂的负载率为42.4%,聚乙二醇修饰后可以降低纳米氧化石墨烯的细胞毒性并提高生物相容性,对KB细胞具有双重的杀伤作用,为纳米氧化石墨烯在肿瘤治疗的临床应用提供了理论依据。     

The application of copolymer-coated graphene oxide-Fe3O4 in the highly efficient synthesis of 2′-aminospiro[indeno[1,2-b]quinoxaline-11,4′-[4'H] pyran]-3′-carbonitrile and 2′-aminospiro[indeno-2,4′-[4'H]pyran]-3′-carbonitrile

A magnetic nanocomposite based on graphene oxide was prepared. Fe₃O₄ nanoparticles were loaded on graphene oxide sheets and GO-Fe₃O₄ was covered by aniline-pyrrole copolymer to afford poly(Py-co-Ani)@GO-Fe₃O₄. This nanocomposite was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, vibrating sample magnetometry, X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy techniques, and its catalytic activity was evaluated in the multicomponent synthesis of 2′-aminospiro[indeno[1,2-b]quinoxaline-11,4′-[4'H]pyran]-3′-carbonitrile and 2′-aminospiro[indeno-2,4′-[4'H]pyran]-3′-carbonitrile derivatives. This magnetically separable catalyst is heterogeneous noncorrosive, highly efficient, and reusable.     

Design of Novel Catalysts Based on Acridine Derivatives Immobilized on Carbon Materials for Molecular Hydrogen Production

Russian Journal of General Chemistry - Immobilization of acridine and its derivatives (9-phenylacridine and N-methyl-9-phenylacridinium iodide) has been studied and quantitative data on physical...     

Functionalization of graphene by electrophilic alkylation of reduced graphite

The reaction of Na/K-reduced graphite with hexyliodide represents a new, versatile and mild approach to synthesize alkylated graphene derivatives, which were characterized by a combination of Raman spectroscopy, TEM and TGA/MS analysis.     

Photoelectron spectra and electronic structure of aza-boron-dipyridomethene derivatives

The electronic structure of three aza-boron-dipyridomethene derivatives containing different hydrocarbon groups at the boron atom is studied by ultraviolet photoelectron spectroscopy and calculations at the density functional theory level. According to the experimental and theoretical data, the higher occupied molecular orbitals of anthracene, acridine, and the studied complexes are of the same character. For the three studied compounds, the effect of alkyl and phenyl substituents on the electronic structure is determined. The parameters of the electronic structure of aza-boron-dipyridomethene (phenyl groups at the boron atom) and its β-diketonate analogue are compared. It is shown that in an energy range up to 11 eV the calculated results correlate with the ultraviolet photoelectron spectra.     

离子液体/石墨烯复合光固化涂层的制备及性能研究

石墨烯在聚合物基体中分散不良是制约其应用的一个重要原因，尤其在石墨烯含量较高时，团聚不可避免。本文通过季铵化、亲核取代和阴离子置换反应，合成了双官光聚合离子液体单体。将其与石墨烯混合分散后，再和光固化环氧丙烯酸树脂6215-100复配，制备不同比例的复合涂层配方，并采用UV固化的方式在玻璃基材上成膜。利用衰减傅里叶全反射红外（ATR-FTIR）和核磁氢谱（¹HNMR）对可聚合离子液体单体进行结构表征，而复合配方的光聚合动力学、涂层的热性能和石墨烯的分散情况则通过实时红外（RTIR）、热重分析（TGA）和显微镜等手段进行表征。结果表明，光聚合离子液体对于石墨烯的分散具有良好的促进作用，涂层在1%和3%石墨烯含量的情况下表现出良好的热性能。     

有机磷系及石墨烯阻燃环氧树脂研究进展

环氧树脂作为一种优异的树脂基体,被广泛地应用于众多领域,但因其极易燃烧,所以常常需要对其进行阻燃处理。本文简要综述了近几年有机磷系化合物及石墨烯阻燃环氧树脂的研究进展,其中有机磷系化合物阻燃部分重点介绍了以阻燃剂中间体9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)及其衍生物和聚磷酸铵(APP)为代表的含磷阻燃剂在环氧树脂中的阻燃机理和阻燃进展;同时也介绍了石墨烯及其衍生物在环氧树脂阻燃领域的最新研究进展,并对其发展前景进行了展望。