Reduction of iron(II) octaethyltetrapyrazinoporphyrazine, FeIITPyzPzEt8, by zinc dust allowed the preparation of crystalline salt (PPN+)2{FeII(TPyzPzEt8)4–(ZnCl2)2}2– (1) (PPN+ is bis(triphenylphosphoranylidene)ammonium). Metal atom zinc transfers two electrons to FeIITPyzPzEt8 forming the {Fe(TPyzPzEt8)}2– dianions which coordinate two ZnCl2 units on the periphery of the TPyzPzEt8 macrocycle. Tetrahedral environment around the zinc(II) atoms is formed with the length of the Zn–N bonds of 2.071(7) Å with meso- and 2.304(8) Å with pyrazine nitrogen atoms of TPyzPzEt8. Optical and EPR spectra show the formation of diamagnetic tetraanionic {TPyzPzEt8}4– macrocycle in 1, and as a result, two-electron reduction of FeIITPyzPzEt8 is centered exclusively on the macrocycle. According to DFT calculations for the {Fe(TPyzPzMe8)(ZnCl2)2}2– and {Fe(TPyzPzMe8)}2– dianions the reason of that is strongly increased electron affinity of the TPyzPzMe8 macrocycle at the coordination of two ZnCl2 units. Obviously, this situation is different from iron(II) phthalocyanine which shows metal-centered first and second reduction. 相似文献
Novel gemini (tail-head-spacer-head-tail) bis-quaternary ammonium compounds (bis-QACs) with a biphenyl spacer between two pyridinium heads were synthesized and compared with commonly used antiseptics such as benzalkonium chloride (BAC) and chlorhexidine digluconate (CHG). The series of compounds showed high inhibitory activity against five bacterial strains and two fungi. The compounds, which contain C8H17-C10H21 aliphatic tails best within the series. A counterion change does not affect MIC in general. Cytotoxicity on human embryonic kidney cells and haemolysis were also investigated. For bis-QACs cytotoxic effect was lower than for 3,3′-[1,4-phenylenebis(oxy)]bis(1-dodecylpyridinium) dibromide (3PHBO-12), that is their closest structural analogue, and for BAC. 相似文献
We consider infinitely convolved Bernoulli measures (or simply Bernoulli convolutions) related to the -numeration. A matrix decomposition of these measures is obtained in the case when is a PV number. We also determine their Gibbs properties for being a multinacci number, which makes the multifractal analysis of the corresponding Bernoulli convolution possible. 相似文献
The reported dielectric barrier discharge (DBD) source comprises of a ceramic‐covered copper electrode, and plasma can be ignited in ambient air with grounded ‘opposite’ electrodes or with objects of high capacitance (e.g., human body), when breakdown conditions are satisfied. Filamentary plasma mode is observed when the same source is operated using grounded opposite electrodes like aluminium plate and phosphate buffered saline solution, and a homogeneous plasma mode when operated on glass. When the source is applied on human body, both homogeneous and filamentary discharges occur simultaneously which cannot be resolved into two separate discharges. Here, we report the characterization of filamentary and homogeneous modes of DBD plasma source using the above mentioned grounded electrodes, by applying optical emission spectroscopy, microphotography and numerical simulation. Averaged plasma parameters like electron velocity distribution function and electron density are determined. Fluxes of nitric oxide, ozone and photons reaching the treated surface are simulated. These fluxes obtained in different discharge modes namely, single‐filamentary discharge (discharge ignited in same position), stochastical filamentary discharge and homogeneous discharge are compared to identify their applications in human skin treatment. It is concluded that the fluxes of photons and chemically‐active particles in the single filamentary mode are the highest but the treated surface area is very small. For treating larger area, the homogeneous DBD is more effective than stochastical filamentary discharge.
A new synthetic approach to 6-alkenyl-substituted pyridoxine derivatives was developed based on the Heck reaction. The reaction, which was catalyzed using a mixture of Pd(OAc)2, (o-Tol)3P and Bu3N as a base, led to seven new 6-alkenyl pyridoxine derivatives. When acrylic acid was used the products of decarboxylation and dimerization were formed. 相似文献
