Jingui Qin

Synthesis and properties of a new ferromagnetic 2,2′-bipyridine-MnPS3 intercalation compound

Abstract A new intercalation compound Mn0.86PS3(bipy)0.56 has been synthesized by a direct reaction of MnPS3 with 2,2-bipyridine. It has been characterized by elemental analyses, thermogravimetry analysis, infrared spectroscopy and X-ray powder diffraction. The magnetic properties of the materials was studied with SQUID-magnetometer. The results indicate that the material exhibits bulk ferromagnetism below 40 K.

EPR studies on BEDT-TTF intercalated MnPS3 molecular magnet

Abstract Frequency and temperature dependence of magnetic properties of BEDT-TTF intercalated molecular magnet MnPS3 have been studied by electron paramagnetic resonance (EPR) technique at X-, K-,and Q-bands. A very strong and relatively narrower (than expected 400–500xa0G from overlapped six hyperfine transitions of paramagnetic Mn2+ ion) single EPR peak in X-band spectra has been observed at all the temperature range, implying collective precession of Mn2+ spins. The EPR signal intensity and linewidth were observed to change dramatically at about 45xa0K, indicating a magnetic phase transition. However, a very sharp decrease in EPR signal intensity and accompanying line bradening below TC indicates a very strong spin canting (and frustration) at lower temperatures. Some small and relatively smooth changes at about 30, 100 and 185xa0K are appeared as well. An almost linear dependence of resonance field to frequency has been observed for K- and Q-band spectra. By the analysis of the frequency dependent resonace field of EPR signal, the effects of the internal field is refined and thus the spectroscopic g-factor and internal field were determined to be g=1.9773 and H i =104 G , respectively. However, a very small non-linearity in Hr versus frequency curve was atributed to the external field dependency of the internal field through magnetic susceptibility.

Bismaleimide resins modified by bi- or tri-allyl-functionalized azo chromophores for second-order optical nonlinearity

Several novel azo dye chromophores with allyl groups at one or two ends of the molecules were synthesized. Differential scanning calorimetry and thermogravimetric analysis tracing showed that these chromophores can be thermally cured with bismaleimidodiphenyl methane to afford a series of crosslinked, and chromophore-modified bismaleimide resins without any appreciable decomposition up to >300°C, while IR spectra analysis indicated that it is not a trivial task to achieve highly-crosslinked BMI resins due to decomposition of the azo dye chromophores. The effects of different chromophores on the curing conditions and thermal stability of these modified BMI resins are discussed. It is noticeable that incorporating a chromophore into the network of BMI resins by its reactive groups at both ends facilitates improvement of the thermal stability of the materials.

Synthesis of polysiloxanes exhibiting both photoconductive and electro-optical properties

Abstract We have synthesized a novel kind of multifunctional polysiloxane containing charge-transporting agents and electro-optical chromophores as side chains for photorefractive application. The chemical structural characterization of this kind of polymer is presented by 1 H-NMR, IR spectra and elemental analysis.

X-,K- and Q-band ESR studies on intercalated Fe0.9PS3(Phen)0.4

Abstract The temperature and frequency dependences of electron spin resonance parameters of polycrystalline powders of intercalated Fe 0.9 PS 3 (Phen) 0.4 have been studied in the temperature range 9–300xa0K. A very strong and relatively broad single ESR peak in X-,K-and Q-band spectra have been observed. However, a very sharp decrease in X-band ESR signal intensity and accompanying line broadening below 15xa0K indicates a very strong spin frustration at lower temperatures. K- and Q-band spectra show almost a linear dependence of resonance field on frequency. From the analysis of the frequency-dependent resonance field of ESR signal, the effects of the internal field is refined and thus the spectroscopic g -factor and internal field were determined to be 1.9576 and 197xa0G, respectively. Also very small non-linearity in H r versus frequency curve was attributed to the external field dependency of the internal field through magnetic susceptibility. Some small and relatively smooth changes at about 40, 80 and 160xa0K appeared as well, indicating some kind of magnetic anomolies.

BEDT-TTF being inserted into a layered MnPS3

Abstract BEDT-TTF was inserted into the layered MnPS 3 by ion exchange reaction of a new pre-intercalate Mn 0.86 PS 3 (bipy) 0.56 with (ET) 2 I x affording a novel inorganic-organic nano-composite material, the intercalate Mn 0.86 PS 3 (ET) 0.46 . The expansion of the lattice spacing is the largest in the intercalates based on MPS 3 so far. It shows a conductivity (on compressed pellet) 10 5 times higher than that of the pristine MnPS 3 .

Electron Paramagnetic Resonance study of magnetic ordering in MnPS3, Mn0.79PS3(4,4'-bipy)0.42 and Mn0.84PS3(1,10-Phen)0.64 compounds

Abstract We report Electron Paramagnetic Resonance (EPR) studies on intercalation ferromagnets Mn0.79PS3(4,4′-bipy)0.42 and Mn0.84PS3(1,10-phen)0.64 and their antiferromagnetic host MnPS3, in the temperature range 300–15 K. The nature of the organic guest cation appears to have a strong influence on the magnetic behaviour of this inorganic-organic hybrid system. The continued appearance of the exchange-narrowed sharp line, characteristic of the paramagnetic phase, even at 15 K suggests that the bulk of the intercalate ferromagnets in this system do not attain a completely ordered state.

Synthesis and characterisation of polyaniline catalysed and doped by squaric acid

Aniline was polymerized in dilute aqueous squaric acid and the polyaniline (PAn) was doped with 10−1–10−3 mol/L of squaric acid. The corresponding electrical conductivity of the PAn is 10−1–10−2 S ⊙ cm−1. The solubility of the doped PAn has been improved in common polar organic solvents. The FTIR and UV—Vis spectra show that the PAn has the structure of both quinone and imine.

Synthesis and second-order optical nonlinearity of carbazolyl-substituted furan chromophores with high thermal stability and good transparency

A series of new chromophores, in which N-hexylcarbazole acts as an electron donor and a furan ring is part of a conjugation bridge, are synthesised, and exhibit similar values of the first molecular hyperpolarisability, but better transparency compared with their analogues which contain diethylaminophenyl instead of N-hexylcarbazole as the donor, in addition to high thermal stability.

Studies on the Structure of Self-Assembled Monolayer of Phenylazonaphthalene

Abstract The structure of a self-assembled monolayer (SAM) of 1-mercapto-6-[1-(4-phenylazonaphthoxy)]hexane (1) has been investigated by UV-vis spectroscopy, atomic force microscopy and Grazing-Incidence Fourier Transform Infrared Spectroscopy. The results support the hypothesis that the molecules are firstly chemisorbed, and then oriented during a long period to achieve a good orientation. The morphology of SAM consists of large domains (ca. 100 nm wide by ca. 410 nm long) almost parallel to each other.