The complexes of pyridine-2-aldoxime (HPOX) and 6-methylpyridine-2-aldoxime (HMPX) with iron (II) thiocyanate of the type [Fe(L)(NCS)2] (L=HPOX and HMPX) have been prepared and characterized. A study of X-ray, magnetic, vibrational spectra (conventional and far-infrared), electronic spectra andMössbauer spectra has indicated that these complexes have polymeric, pseudo octahedral, coordination geometry with linear bridging thiocyanate ligands. The electronic spectra of mono complexes show a larger, low symmetry, ligand field than that present in [Fe(L)2(NCS)2] complexes. UnperturbedMössbauer spectra show a large quadrupole splitting, EQ, and smaller isomer shift values in these iron (II) thiocyanate complexes. The magnetically perturbedMössbauer spectra of these iron(II) thiocyanate complexes at room temperature show that the principal component of the electric field gradient tensor is positive and corresponds to adxy (5B2) ground state.With 2 Figures 相似文献
Fabricating mechanically strong hydrogels that can withstand the conditions in internal tissues is a challenging task. We have designed hydrogels based on multicomponent systems by combining chitosan, starch/cellulose, PVA, and PEDOT:PSS via one-pot synthesis. The starch-based hydrogels were homogeneous, while the cellulose-based hydrogels showed the presence of cellulose micro- and nanofibers. The cellulose-based hydrogels demonstrated a swelling ratio between 121 and 156%, while the starch-based hydrogels showed higher values, from 234 to 280%. Tensile tests indicated that the presence of starch in the hydrogels provided high flexibility (strain at break?>?300%), while combination with cellulose led to the formation of stiffer hydrogels (elastic moduli 3.9–6.6 MPa). The ultimate tensile strength for both types of hydrogels was similar (2.8–3.9 MPa). The adhesion and growth of human osteoblast-like SAOS-2 cells was higher on hydrogels with cellulose than on hydrogels with starch, and was higher on hydrogels with PEDOT:PSS than on hydrogels without this polymer. The metabolic activity of cells cultivated for 3 days in the hydrogel infusions indicated that no acutely toxic compounds were released. This is promising for further possible applications of these hydrogels in tissue engineering or in wound dressings.
Summary The products from the reaction oftrans-dioxobis(ethylenediamine)rhenium(V) halides with hydrogen halides have been investigated. Dilute (2M) and concentrated hydrochloric acid react with (ReO2en2)Cl in the cold to give ReO(OH)enCl2 and IRe(OH)2enCl2]Cl respectively, while with hot 6M HCl [ReOCl5]2– is formed. Dilute solutions of HX protonate [ReO2en2]X (X = Br and I) giving [ReO(OH)en2]X2 which are converted slowly into ReO(OH)enBr2 and [ReO(OH)en2](I3)2. Hot and concentrated solutions of HX reduce Rev in (ReO2en2 )X (X = Br and I) giving enH2(ReBr6) and ReI4en. The thermal decomposition of (ReO2en2)X (X = Cl, Br and I) has been studied by thermogravimetry and a polymeric compound, Re2O7en2, has been isolated by heating (ReO2en2)X at 200°. The compounds have been characterised by molecular conductivities, magnetic susceptibility and i.r. spectra. 相似文献
In this note we show that the characterization results for P-matrices due to K.G. Murty and A. Tamir which state that a given square matrixM of ordern is a P-matrix if and only if the linear complementarity problem (q, M) has a unique solution for allq in a specified finite subset of n depending onM are incorrect whenn > 3.Research supported by Dr. K.S. Krishnan (DAE) fellowship for research in Mathematics and Computer Science, Bombay, India. 相似文献
Summary For a sequence {Xn:n=0, 1, 2,...} of i.i.d. discrete random variables let X0 denote the zeroeth record value and XL(1), the first record value. It is shown that X0 and XL(1) –X0 are identically distributed if and only if X0 has the geometric distribution over the lattice k :k=1, 2,... for some >0. 相似文献
Evidence is presented which indicates that singlet → triplet intersystem crossing from the charge-transfer singlet state of electron donor-acceptor complexes is efficient only when a locally excited triplet state of a component molecule (donor or acceptor) lies below the charge-transfer singlet state. 相似文献
A library of 24 glycoconjugates related to glycosylated beta-amino acid derivative (I) was been prepared and screened against DNA topoisomerase-II of the filarial parasite S. cervi. Among these, compound 6 was found to be a potent inhibitor of DNA topoisomerase-II with 95% inhibition at 1.09 microM. Furthermore, compound 6 was at least three times more potent than the lead compound, glycosylated beta-amino acid derivative I. 相似文献
Preconcentration of Cd(II), Cu(II), Mn(II), Ni(II), Pb(II) and Zn(II) in saline matrices on Amberlite XAD-4 resins coated with ammonium pyrrolidine dithiocarbamate (APDC) and piperidine dithiocarbamate (pipDTC) and subsequent determination by inductively coupled plasma atomic emission spectrometry were studied. Parameters such as effect of pH, effect of HNO(3) concentration on elution of metals from resin were studied. The results show that Amberlite XAD-4 coated with APDC was more efficient in the recovery of metal ions compared with Amberlite XAD-4 coated with pipDTC, in the concentration range of 0.1-200 mug l(-1), for 1 g of Amberlite XAD-4 coated resin. The detection limits for Cd(II), Cu(II), Mn(II), Ni(II), Pb(II), Zn(II) are 0.1, 0.4, 0.3, 0.4, 0.6, 0.5 mug l(-1), respectively, for resin coated with APDC and 0.7, 1.0, 0.8, 0.9, 1.7 and 1.2 mug l(-1) for resin coated with pipDTC. The effect of diverse ions on the determination of aforesaid metals was studied. The method was applied for the determination of trace metal ions in artificial sea water and natural water samples. The results were compared with extraction AAS method. 相似文献