硫醇分子链长对氧化还原自组装多层膜电化学行为影响的初步研究(英文)

以烷基硫醇和二茂铁衍生物构建的氧化-还原自组装多层膜为模型体系,研究烷基硫醇分子链长对多层膜电化学行为的影响.实验表明,二茂铁基团和电极之间的电子传递反应速率随两者距离的增加呈现指数级下降的趋势;烷基硫醇分子链长对自组装膜电化学行为的影响于不同情况下表现不同.本实验条件下,当多层膜上的电活性基团与电极比较接近时,长链分子自组装膜呈现较强的电化学响应.而当电极与电活性基团之间的距离较远时,短链烷基硫醇分子自组装膜呈现较强的电化学响应.     

二茂铁基聚合物超分子体系构建和性能的研究进展

二茂铁基聚合物具有独特的氧化还原、电、磁等性能，其构建成超分子体系后在传感器、催化、分子电子学、生物和医学等领域有着广泛的应用前景。本文综述二茂铁基线型聚合物和二茂铁基树枝状聚合物的超分子体系构建和性能方面的研究进展，并对今后的发展方面作一展望。     

二茂铁衍生物L—B膜修饰SnO2电极的性能

用外层单电子快速转移的氧化还原剂二茂铁及其衍生物修饰电极,在电极/溶液界面作为电子传递的中介物,可使电极上进行的慢反应得到加速、起中介催化作用。目前研究较多的是共价键合和高分子膜的修饰,其他方式的修饰报道不多。用能实现分子有序化排列的L-B膜技术进行氧化还原电活性分子的修饰电极还未见报道。我们用L-B膜技术在SnO_2电极上修饰了二茂铁的衍生物-硬脂酸二茂铁酯(FcOCOC_(17)H_(35))双亲化合物,曾研究了修饰膜的电化学可逆行为和稳定性。本文研究硬脂酸二茂铁酯L-B膜修饰的SnO_2电极     

二茂铁查尔酮衍生物的电化学与热性质

合成并表征了含有苯环(3a~3d)和萘环(3e~3h)的两系列二茂铁查尔酮衍生物.这些化合物具有较好的紫外可见吸收性质.循环伏安实验中代表化合物3b与3f均展示可逆的单电子氧化还原进程,且萘环取代苯环对二茂铁的氧化还原性质未产生影响.与二茂铁相比,二茂铁查尔酮衍生物难失去电子,稳定性增加.热性质研究表明,两系列化合物均在250~260℃左右开始降解,对于同一系列化合物3a~3d或3e~3h,随着烷基链的增加,熔点都出现下降趋势.当分子刚性部分以苯环为主时,随着烷基链的加长,第一次升温中发生了不稳定的多晶相转变;当分子含有萘环时,分子熔点升高,此时延长烷基链对晶相的稳定性影响不大.这些研究为此类化合物在功能材料方面的应用提供一定的理论依据.     

二茂铁衍生物光学特性的氧化还原开关效应

设计合成了三种具有推拉电子取代基的二茂铁衍生物D-Fc-R(1), D-Fe-A1(2), [D-Fc-A2(3)N-C6H4-CH=CH, R :CH2OH, A1 : CHO, A2 : CH=C(CN)2], 并对其循环伏安及光谱电化学行为进行了研究。三种衍生物均出现两个氧化还原电时,1的两个电对均可逆, 单扫第一电对, 2的第一电对是可逆, 3的第一电对是准可逆, D-Fc^+-R在613nm, D-Fc^+-A1在705nm有强LMCT带, 具有良好的光学特性氧化还原开关效应。     

二茂铁乙炔苯巯基化合物的合成及电化学性质

以室温下Zn/Me2SiCl2/DMA还原体系代替传统低温下(-78 ℃)有机锂试剂体系,高收率合成了4-乙酰巯基碘苯(6)和4-碘苯甲硫醚(7)。 分别将二者与二茂铁乙炔偶联合成了二茂铁乙炔基苯硫酚衍生物1和2。 研究了衍生物1和2的光谱和电化学性质,将其自组装到金电极上,获得了电活性较好的修饰电极。 衍生物1修饰Au/GCE电极对芦丁有良好的催化电氧化作用,在生物/电化学传感器领域有潜在应用前景。     

温度/氧化还原双响应超分子胶束的制备及释药性能研究

以溴酰化β-环糊精(β-CD-Br)为引发剂,通过原子转移自由基聚合(ATRP)制备了以β-CD为核的温敏星形聚N-异丙基丙烯酰胺(β-CD-PNIPAM)。以具有氧化还原性质的二茂铁-聚乙二醇(Fc-m PEG)为客体分子,通过环糊精和二茂铁的主-客体识别作用自组装得到温度/氧化还原双响应超分子复合胶束(β-CD-PNIPAM/Fc-mPEG)。结果表明,超分子复合胶束具有规则的球形结构,直径约为100nm左右,具有可逆的温度和氧化还原刺激响应性。当升高温度至胶束的LCST以上且加入不同浓度的H2O2时,胶束结构破坏,实现药物的可控释放。这种具有良好温度和氧化还原双响应特性的超分子胶束是抗癌药物的良好载体。     

酸碱调控的二茂铁咪唑电化学开关

本文设计合成了一系列具有共轭结构的二茂铁咪唑衍生物,它们在质子的作用下呈现显著的光谱、核磁及电化学响应.在中性(或碱性)环境中,其氧化还原波处于低电位,表现为分子"关"的状态;在酸性环境中,其氧化还原波处于高电位,表现为分子"开"的状态;通过酸碱的调控作用其氧化还原波可以在高、低电位之间可逆转换,能够作为一类新型的电化...     

单取代与1,1'-双取代1,2,3-三唑基二茂铁衍生物的光谱、电化学与热性质

合成并表征了一系列单取代及1,1'-双取代1,2,3-三唑基二茂铁衍生物.与单取代二茂铁衍生物相比,1,1'-双取代二茂铁衍生物具有较大的摩尔吸光系数.荧光光谱中,烷氧链的增加和氯原子的引入均使化合物的荧光强度减弱,量子产率降低.循环伏安实验中,代表化合物展示准可逆的单电子氧化还原进程,并且1,1'-双取代三唑基二茂铁衍生物的半波氧化还原电位较单取代化合物向阳极移动150 m V左右,表明前者难于发生失电子氧化反应.热性质研究表明,这些化合物的降解温度在285~305℃之间.含有单烷氧链的单取代二茂铁衍生物熔点较高,在加热过程中未熔解而是直接发生了降解反应;含有多烷氧链的化合物熔点降低,在加热和冷却过程中有的发生了单晶相的熔解和凝固过程,有的发生了多晶相到液相的转变.     

乙烯基二茂铁共聚物修饰电极的研究进展

乙烯基二茂铁具有良好的电性能、磁性能和氧化还原性能,且由乙烯基二茂铁和带功能性基团的乙烯基单体共聚合成的聚合物电介体弥补了小分子电介体存在易流失的缺点,具有广泛的应用前景。乙烯基二茂铁在聚合过程中容易发生"分子内电子转移",溶剂效应和位阻效应可能是诱发该反应发生的原因。本文概述了乙烯基二茂铁自由基聚合的特点及其修饰电极常用的制备和表征方法,并着重分析了测试电位、膜厚度、温度、乙烯基二茂铁结构单元含量以及残留单体对酶电极的影响。     

新型二茂铁甲基季铵盐离子液体的合成与表征

以二茂铁与二甲胺为原料合成了碘化二茂铁甲基季铵盐,再经复分解反应得到乙酸二茂铁甲基季铵盐离子液体;表征了离子液体的结构,测定了其熔点和溶解性.结果表明,合成的乙酸二茂铁甲基季铵盐离子化合物熔点低于100℃,是一种新型的二茂铁甲基季铵盐离子液体.     

Synthesis, characterization and crystal structures of boron-containing intermediates in the reductive amination of ferrocenecarboxaldehyde to a bis(ferrocenylmethyl) amine

Reaction of ferrocenecarboxaldehyde with aqueous methylamine leads to [(methylimino)methyl]ferrocene, which is reduced to N-(ferrocenylmethyl)-N-methylamine by NaBH₄. This amine reacts with ferrocenecarboxaldehyde and NaCNBH₃ to give the tertiary ammonium salt, di(N-(ferrocenylmethyl))-N-methylammonium cyanoborohydride. Hydrolysis of the NaCNBH₃ reaction mixture produces the free amine, di(N-(ferrocenylmethyl))-N-methylamine. Thermolysis of di(N-(ferrocenylmethyl))-N-methylammonium cyanoborohydride in refluxing tetrahydrofuran converts it to the cyanoborane adduct, di(N-ferrocenylmethyl)-N-methylamine-cyanoborane, with elimination of H₂. The new compounds are fully characterized by using spectroscopic and physical methods, including X-ray crystal structure determinations of di(N-(ferrocenylmethyl))-N-methylammonium cyanoborohydride, di(N-(ferrocenylmethyl))-N-methylamine, and di(N-(ferrocenylmethyl))-N-methylamine-cyanoborane.     

Synthesis of versatile intermediates of the ferrocene series: reductive amination of ferrocenecarbaldehyde

Reductive amination of ferrocenecarbaldehyde with several primary and secondary amines in the presence of sodium triacetoxyborohydride was studied. This method was used for the synthesis of new ferrocenylmethylamines, viz., N-(ferrocenylmethyl)isoleucine methyl ester, N,N-bis(ferrocenylmethyl)glycine ethyl ester, and N-(3,5-dibenzyloxybenzyl)-N-(ferrocenylmethyl)methylamine. The latter is a potential precursor of a dendrimer with the chiral ferrocenyl plane in the core.     

Synthesis, structure and redox potentials of biologically active ferrocenylalkyl azoles

The syntheses, structures, electrochemical properties of the series of ferrocenylalkyl azoles, FcAlkAz, as well as the antitumor activity of ferrocenylmethyl benzimidazole (8) have been studied. Above mentioned compounds were investigated by the method of cyclic voltametry. All of them exhibited a reversible one-electron oxidation-reduction wave owing to the ferrocene-ferrocenium redox couple with a positive shift (0.50-0.65 V) compared with that of ferrocene (0.42 V). The X-ray determination of molecular structures of 1-(ferrocenylmethyl)imidazole (4), 1-(ferrocenylbenzyl)imidazole (7) and 1-(ferrocenylmethyl)bezimidazole (8) was carried out. Compound 4 with imidazolyl substituent was found to be present in N-protonated form. Antitumor activity of 1-(ferrocenylmethyl)benzimidazole (8) against some solid tumor models such as adenocarcinoma 755 (Ca755), melanoma B16 (B16) and Lewis lung carcinoma was studied. The antitumor activity of compound 8 was compared with cisplatin effectiveness against some experimental tumor systems.     

Organometallic derivatives V. The lithiation of ferrocenylmethyl cyanide

Ferrocenylmethyl cyanide has been dilithiated with n-butyllithium and condensation of the lithiated intermediate with benzyl chloride gave α,α-dibenzylferrocenylmethyl cyanide. The lithioferrocene was also condensed with methyl iodide, butylbromide and 1,2-dichloroethane to give the corresponding α-disubstituted ferrocenylmethyl cyanides. The reactions of these α-disubstituted ferrocenylmethyl cyanides with n-butyllithium and lithium aluminium hydride have been investigated.     

The first (ferrocenylmethyl)imidazolium and (ferrocenylmethyl)triazolium room temperature ionic liquids

N-(Ferrocenylmethyl)imidazole (3a), 1-(ferrocenylmethyl)-1,2,4-triazole (3b), 1,1'-bis[(1H-imidazol-1-yl)methyl]ferrocene (8a), 1,1'-bis([1H-(2-methyl)imidazol-1-yl]methyl]ferrocene (8b), and 1,1'-bis[(1H-1,2,4-triazol-1-yl)methyl]ferrocene (8c) were synthesized in moderate yields. These compounds were quaternized with methyl iodide to form 1-(ferrocenylmethyl)-3-methylimidazolium iodide (4a), 1-(ferrocenylmethyl)-4-methyl-1,2,4-triazolium iodide (4b), 1,1'-bis([1-(2,3-dimethyl)imidazolium]methyl)ferrocene diiodide (9b), and 1,1'-bis([1-(4-methyl)-1,2,4-triazolium]methyl)ferrocene diiodide (9c), respectively, in excellent yields. Compounds 4a, 4b, 9b, and 9c were metathesized with bis(trifluoromethanesulfonyl)amide to give high yields of 5a, 5b, 10b, and 10c. With potassium hexafluorophosphate, 9b forms 10d. Salts 5a, 5b, and 10c are the first room-temperature ionic liquids with cations containing an organometallic moiety that exhibit T(g) values well below room temperature, i.e., -32, -16, and -11 degrees C. The compounds were characterized by (1)H, (19)F, and (13)C NMR, MS, and elemental analyses. T(g) values and melting points were determined by DSC. T(d) values (5% weight loss temperature) were recorded by TGA. X-ray single-crystal structures show that 9c and 10d crystallize in the triclinic space group P.     

Evaluation of enantiopure N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol for catalytic asymmetric addition of organozinc reagents to aldehydes

A facile and practical approach to preparation of enantiopure N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol was developed from cheap and easily available l-(+)-methionine. Synthetic highlights include the three-step, one-pot construction of the chiral azetidine ring and the development of an improved one-step procedure for the synthesis of the key intermediate l-2-amino-4-bromobutanoic acid. Enantiopure N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol was evaluated for catalytic asymmetric addition of organozinc reagents to aldehydes. The asymmetric ethylation, methylation, arylation, and alkynylation of aldehydes achieved enantioselectivity of up to 98.4%, 94.1%, 99.0%, and 84.6% ee, respectively, in the presence of a catalytic amount of chiral N-(ferrocenylmethyl)azetidin-2-yl(diphenyl)methanol. Our results demonstrated further that the four-membered heterocycle-based backbone was a good potential chiral unit for the catalytic asymmetric induction reaction, and the hindrance of the bulky ferrocenyl group, compared to a phenyl group, played an important role in the enantioselectivities. A possible transition for the catalytic asymmetric addition has been proposed on the basis of the crystal structure of the chiral ligand 3b including two HOAc molecules and previous studies.     

1,3-Di(Ferrocenylmethyl)Imidazolium and 1-Ferrocenylmethyl-3-Alkylimidazolium Salts: A High Yield and Facile Synthesis

We have developed a rapid facile synthesis of 1-ferrocenyl-3-alkyl and 1,3-di(ferrocenylmethyl)imidazolium salts. The imidazolium salts are formed in excellent yields.     

Direct synthesis of ferrocenylmethylphosphines from ferrocenylmethyl alcohols and their application as ligands for room temperature Pd(0)-catalyzed Suzuki cross-couplings of aryl bromides

[reaction: see text] The direct, high-yield conversion of readily available ferrocenylmethyl alcohols to ferrocenylmethylphosphines and the application of ferrocenylmethylphosphines as efficient ligands for room temperature Suzuki cross-coupling reaction of aryl bromides with phenylboronic acid are reported. The procedure of directly converting ferrocenylmethyl alcohols to ferrocenylmethylphosphines described here should find applications in the synthesis of many metallocenylmethylphosphines including optically active ones.     

Study on Electrocatalytic Oxidation of L‐Cysteine at Glassy Carbon Electrode by (FcM)TMA and Its Electrochemical Kinetics

The electrocatalytic oxidation of L ‐cysteine by (ferrocenylmethyl)trimethylammonium at a glassy carbon electrode in 0.1 M Na₂SO₄ aqueous solution has been studied. The rate constant for the catalytic reaction was evaluated as (4.28±0.05)×10³ M^?1 s^?1 by chronoamperometry. Experimental conditions, which maximize the current efficiency of the electrocatalytic oxidation, such as pH value and the concentration of the catalyst, were also investigated. The experimental results of electrocatalytic kinetics of L ‐cysteine oxidation on GCE in the presence of (ferrocenylmethyl)trimethylammonium obviously support the reaction mechanism proposed and the rate determining step assumed in scheme described in this work.