Synthesis of dihydropyrazole‐bridged dinuclear ferrocenyl derivatives and their catalytic effect on thermal decomposition of ammonium perchlorate

Dihydropyrazole‐bridged dinuclear ferrocenyl derivatives (3a–3c) have been synthesized by the reaction of 1,3‐diferrocenyl‐2‐propen‐1‐on (1) with hydrazine, then acylation with acyl chloride directly. The structures were determined by mass spectrometry, IR and ¹H NMR spectroscopy. The compound 3c was characterized by single‐crystal X‐ray analyses. It was found that compounds 3a–3c have significant catalytic effect on the decomposition of ammonium perchlorate (AP). Compared with the thermal decomposition of pure AP, adding 3a, 3b and 3c in AP decreases its decomposition temperature by 78.8, 74.3 and 57.1 °C, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of unsymmetrical pincer CNN palladium complex of 8-dimethylamino-3-ferrocenylmethyl-3-azabicyclo[3.2.1]octane and its catalytic activity in the Suzuki reaction

New bicyclic unsymmetrical CNN palladium 5,6-membered pincer complex was synthesized from 3-ferrocenylmethyl-8-dimethylamino-3-azabicyclo[3.2.1]octane by its direct cyclo-palladation with Li₂PdCl₄ or Na₂PdCl₄ and sodium acetate in MeOH. The obtained complex exhibited high catalytic activity in the Suzuki cross-coupling between aryl bromides and phenylboronic acid.     

Intramolecular O‐arylation using nano‐magnetite supported N‐heterocyclic carbene‐copper complex with wingtip ferrocene

Nano‐magnetite supported N‐heterocyclic carbene‐copper complex with wingtip ferrocene has been prepared via multi‐step procedure. The complex has been characterized by various analytical techniques such as fourier transform infrared (FT‐IR), fourier transform Raman (FT‐Raman), X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) analysis. The catalytic activity of the complex has been exploited in intramolecular O‐arylation of o‐iodoanilides under heterogeneous conditions. The complex could be successfully recycled up to twelve consecutive cycles.     

Quinoline and ferrocene conjugates: Synthesis,computational study and biological evaluations

Novel O‐alkylated quinoline and N‐alkylated 4‐quinolone derivatives attached to the ferrocene moiety through 4,1‐ ( 7a–d , 8a–d and 12a–d ) and 1,4‐disubstituted ( 9a , 9b , 10a and 10b ) 1,2,3‐triazole moiety were synthesized. The observed regioselectivity of O‐ vs. N‐alkylation was explored by the use of NMR and computational techniques. Among the N‐alkylated derivatives, the quinolone‐ferrocene conjugate 9a displayed marked activities against chronic myeloid leukemia in blast crisis (K562) and Burkitt lymphoma (Raji). The 6‐chloroquinolone‐ferrocene conjugate 12c , with selective inhibitory activity on Raji cells and no cytostatic effect on normal MDCK1 cells was highlighted as the most promising anticancer organometallic complex in a group of O‐alkylated quinolines.     

Exploring Planar-Chiral Amino Siloxides

We present the synthesis, structure, and exemplary reactivity of siloxides with a planar-chiral N,N-dimethylaminomethylferrocene backbone. Several zinc complexes based on the racemic as well as the enantiomerically pure silanol were synthesized in the presence of water and crystallographically characterized, and their behavior in solution was examined. The chiral probe present in this system is a valuable tool for identifying the structure in solution. Furthermore, the zinc siloxides exhibit a comparable reactivity to the corresponding silanols. Therefore, they can be regarded as “masked” silanols, especially when the silanols are preparatively inaccessible.     

Conformation‐Controlled Diplatinum(II)–Ferrocene Dyads to Achieve Long‐Lived Charge‐Separated States

Square‐planar polypyridyl platinum(II) complexes possess a rich range of structural and spectroscopic properties that are ideal for designing artificial photosynthetic centers. Taking advantage of the directionality in the charge‐transfer excitation from the metal to the polypyridyl ligand, we describe here diplatinum(II)–ferrocene dyads, open‐butterfly‐like dyad 1 and closed‐butterfly‐like dyad 2 , which were designed to understand the conformation and orientation effects to prolong the lifetime of charge‐separated state. In contrast to the open‐butterfly‐like dyad 1 , the closed‐butterfly‐like dyad 2 shows three‐times long lifetime of charge separated state upon photoexcitation, demonstrating that the orientation in the rigid structure of dyad 2 is a very important issue to achieve long‐lived charge separated state.     

双取代硅基二茂铁的合成方法研究

双取代硅基二茂铁是用于聚硅氧烷类高分子的一种高效抗氧化剂，只要添加０．１‰－０．５‰，可以使聚硅氧烷的使用寿命提高数百倍。     

Multichannel recognition of hydrogen sulphate anion by a Zn(II)–triazole–pyridine complex bearing a ferrocenyl pendant

Receptors ferrocene–triazole–pyridine triads assembled with Zn(II) or Cd(II) metal cations behave as chemosensor molecules for HSO₄ ^?  anions through electrochemical and optical channels: the redox peak of the ferrocene/ferrocenium redox couple is shifted cathodically by 72–53 mV, and a new absorption band appeared in the UV–vis spectrum upon complexation with the HSO₄ ^?  anion. Association constants, detection limits and stoichiometries of the recognition processes have been determined, whereas ¹H NMR experiments and density functional theory calculations are used to suggest the plausible binding mode taking place in the new supramolecular assembly formed.     

二茂铁功能化的两例镉金属有机框架材料的合成、结构和表征※

含有二茂铁单元的1,1'-二茂铁二羧酸(H₂FcDCA)是构筑具有氧化还原活性的金属有机框架(MOFs)的理想配体, 然而由于其不可控的配位模式和扭转角, 目前基于H₂FcDCA的配合物的合成仍然具有挑战性. 本工作中, 利用H₂FcDCA与Cd²⁺反应合成了2个新颖的MOFs. 化合物1中, 镉中心被FcDCA和4,4'-联吡啶(bpy)桥连形成二维层. 在该体系中引入草酸则实现了三维框架的构筑(化合物2). 和1不同, 2中具有双核Cd₂单元, 该单元通过bpy和草酸连接形成具有金刚石型拓扑的框架, FcDCA同时作为功能单元和孔分割配体. 这2个化合物都表现出可见光吸收、光电流响应和典型的二茂铁氧化还原特性, 这些特性使其在光电催化方面具有潜在的应用前景.     

Helically chiral ferrocene peptides containing 1'-aminoferrocene-1-carboxylic acid subunits as turn inducers

We present a detailed structural study of peptide derivatives of 1'-aminoferrocene-1-carboxylic acid (ferrocene amino acid, Fca), one of the simplest organometallic amino acids. Fca was incorporated into di- to pentapeptides with D- and L-alanine residues attached to either the carboxy or amino group, or to both. Crystallographic and spectroscopic studies (circular dicroism (CD), IR, and NMR) of about two dozen compounds were used to gain a detailed insight into their structures in the solid state as well as in solution. Four derivatives were characterized by single-crystal X-ray analysis, namely Boc-Fca-Ala-OMe (16), Boc-Fca-D-Ala-OMe (17), Boc-Fca-beta-Ala-OMe (18), and Boc-Ala-Fca-Ala-Ala-OMe (21) (Boc=tert-butyloxycarbamyl). CD spectroscopy is an extremely useful tool to elucidate the helical chirality of the metallocene core. Unlike in all other known ferrocene peptides, the helical chirality of the ferrocene is governed solely by the chirality of the amino acid attached to the N terminus of Fca. Depending on the degree of substitution of both cyclopentadiene (Cp) rings, different hydrogen-bonding patterns are realized. (1)H NMR and IR spectroscopy, together with the results from X-ray crystallography, give detailed information regarding not only the hydrogen-bonding patterns of the compounds, but also the equilibria between different conformers in solution. Differences in chemical shifts of NH protons in dimethyl sulfoxide ([D(6)]DMSO) and CDCl(3), that is, the variation ratio (vr), is used for the first time as a measure of the hydrogen-bonding strength of individual COHN bonds in ferrocenoyl peptides. In dipeptides with one intramolecular hydrogen bond between the pendant chains, for example, in dipeptide 16, an equilibrium between hydrogen-bonded and open forms is observed, as testified by a vr value of around 0.5. Higher peptides, such as tetrapeptide 21, are able to form two intramolecular hydrogen bonds stabilizing one single conformation in CDCl(3) solution (vr approximately 0). Due to the low barrier of Cp-ring rotation, new and unnatural hydrogen-bonding patterns are emerging. The systematic work described herein lays a solid foundation for the rational design of metallocene peptides with unusual structures and properties.