Zhanxi Bian

Ferrocene and [3]ferrocenophane-based β-diketonato copper(II) and zinc(II) complexes: synthesis, crystal structure, electrochemistry and catalytic effect on thermal decomposition of ammonium perchlorate

Ferrocene and [3]ferrocenophane-based β-diketones and their Cu(II) and Zn(II) complexes have been synthesized and characterized. Single-crystal X-ray diffraction analysis confirmed the molecular structures of the Cu(II) complexes. UV-vis spectroscopy and electrochemical measurements were obtained. All the new compounds showed quasireversible and diffusion-controlled redox processes. The complexes displayed high thermal stability according to the thermogravimetry (TG) measurements. The β-diketone ligands and complexes exhibited high catalytic effects on the thermal degradation of ammonium perchlorate (AP) which was evaluated by TG and differential scanning calorimetry techniques, whereas the addition of Cu(II) complexes lowered the thermal decomposition temperature of AP more dramatically and released more heat compared with the addition of β-diketone ligands or Zn(II) complexes. We expect that this kind of transition metal complexes containing ferrocenyl would has great value in preparing a high burning rate catalyst for composite solid propellants.

Synthesis of cyanohydrin trimethylsilyl ethers of acylferrocenes

Abstract The addition of trimethylsilyl cyanide to acylferrocenes FcCOR (R=Me, Et, nPr, iPr, Ph, p-MeOC6H4, o-ClC6H4, m-ClC6H4, p-ClC6H4, Fc; Fc=C5H4FeC5H5) catalyzed by zinc iodide in methylene chloride provided the corresponding cyanohydrin trimethylsilyl ethers in moderate to high yields. Factors affecting the reaction and yields of adducts were investigated. All new compounds were characterized by IR and 1H NMR spectroscopies. In addition, the adducts of p-chlorobenzoylferrocene and diferrocenyl ketone were structurally determined by X-ray crystallography.

Some new azobenzene liquid crystals involving chalcone and ester linkages

Five new series of azobenzene derivatives containing thiophene, naphthalene or ferrocene with chalcone and ester linkages have been synthesized and characterized. The photosensitive azobenzene group underwent photoisomerization under UV light, which was monitored by UV-visible spectroscopy. The cyclic voltammograms of compounds containing ferrocene showed a quasi-reversible and diffusion-controlled redox process. These compounds displayed high thermal stability according to the thermogravimetry measurements. According to differential scanning calorimetry, thermal polarizing microscopy and powder X-ray diffraction studies, the compounds containing ferrocene and the compounds with three or no terminal alkoxy chains on the side of the ester group all showed no liquid crystal behaviour. However, the compounds with a terminal alkoxy chain on the side of the ester group or a terminal alkoxy chain at both ends of the molecule exhibited enantiotropic mesophases, but the latter had a narrow mesogenic domain. The increase of the length of the mesogenic unit by replacement of the benzene ring with a naphthalene ring resulted in both an increase in the clearing point and in an increase in the mesophase domain.

Electrochemical and liquid crystal properties of ferrocene-based β-diketonato copper(II) and zinc(II) complexes

Heterometallic liquid crystals are of special interest because of the possibility to combine optical, magnetic and electric properties of different metal ions in one mesogenic molecule. In order to investigate new heteropolynuclear mesogenic systems, the long-chain alkyl bromophenyl ferrocenyl β-diketones and their copper(II) and zinc(II) complexes were synthesized and characterized. The X-ray crystal structure reveals that β-diketone ligands exist in the enol isomer form in the crystals. These compounds exhibited good absorption and electrochemical properties. The complexes showed high thermal stability. According to thermal polarizing microscopy and differential scanning calorimetry studies, all complexes display liquid crystal behaviours. The zinc(II) complexes display lower melting point and clear point as well as a wide mesophase range compared with the copper(II) complexes. The obtained metallomesogens are important footsteps toward the development of liquid crystal materials possessing heteropolynuclear, good redox activity and chemically stable ferrocene unit.

Anti-migration and burning rate catalytic performances of novel ferrocene-based porphyrins and their transition-metal complexes

Two series of novel ferrocene-based porphyrins and their transition metal (Zn, Co, Ni, and Cu) complexes were synthesized and characterized. One has ferrocene on the skirt of meso-tetraphenylporphyrin (TPP) via long chain alkoxy groups (HP1 and HP2); the other has a close connection of TPP and ferrocene containing long chain alkyl groups by ester linkage (HP3). Their UV-visible absorption spectra, fluorescence spectra, thermal stability and electrochemical properties were investigated. They were applied for the first time as burning rate catalysts (BRCs) in a simulative solid propellant to overcome the migration problem. Their catalytic effects on the thermal degradation of ammonium perchlorate (AP) were evaluated by thermogravimetric and differential scanning calorimetry techniques, and the results showed that the catalytic effects of free porphyrin, Zn(II) porphyrin and Ni(II) porphyrin were similar to that of catocene. While Cu(II) and Co(II) porphyrins exhibited higher catalytic effects than catocene, the Co(II) complexes lowered the thermal decomposition temperature of AP more dramatically compared with Cu(II) complexes. Whats more, these compounds displayed non-migratory ability in the migration test. Therefore, the novel ferrocene-based porphyrin derivatives are non-migratory BRCs with high catalytic efficiency for composite solid propellants and have potential applications in aerospace.