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81.
82.
83.
A novel convenient synthetic route for poly-functional 21-monothiatetraphenylporphyrins of the type A4 und AB3 having base labile substituents in meso position was developed. Using this method a series of symmetric and asymmetric 21-thiaporphyrins containing different functional groups at the meso position is reported. The new products were characterized by NMR, UV-Vis and mass spectroscopy. 相似文献
84.
Danika Locatelli Silvio Quici Stefania Righetto Dominique Roberto Francesca Tessore Geoffrey J. Ashwell Mukhtar Amiri 《Progress in Solid State Chemistry》2005,33(2-4):223-232
The new ligands (E)-4-[2-(4-(N-methyl-N-hexadecylaminophenyl)ethenyl]pyridine (L1) and 4′-(C6H4-p-N(Me)(hexadecyl))-2,2′:6′,2″-terpyridine (L2) were prepared along with their complexes [cis-Ir(CO)2ClL1], [fac-Os(CO)3Cl2L1], [ZnCl2L2] and [IrCl3L2]. Whereas these complexes show a large second-order nonlinear optical (NLO) response at the molecular level, similar to that of related organic alkylated salts as evidenced by the Electric Field Induced Second-Harmonic (EFISH) generation technique, their Langmuir–Blodgett (LB) film susceptibility is lower than that of the salts. 相似文献
85.
Giuseppe Arena Salvatore Musumeci Enrico Rizzarelli Silvio Sammartano Carmelo Rigano 《Transition Metal Chemistry》1980,5(1):297-299
Summary The formation constants of species formed in the systems H+-Zn2+-cysteine and H+-Zn2+-cystine have been determined in aqueous solution at 37° and I = 0.15 mot dm–3 (NaClO4), using the pH-metric method. The existence of the following species [ZnL], [ZnL2], [ZnL2H] and [Zn2L3] (2.3 pH 7.7) was proved for the Zn2+-cysteine system, whereas for the Zn2+-cystine [Zn2L] (5.3 pH 6.4) was the only species found. In the Zn2+-cystine system the pH range was severely restricted because of precipitation occurring at pH > 6.4. A new experimental and numerical approach was employed in order to implement the possibility of rigorously selecting the species present in each system. The results have been compared with data previously reported on the same systems, considering in particular the different sets of species found in the various works. 相似文献
86.
Silvio Aime Luciano Milone Rosanna Rossetti Pier Luigi Stanghellini 《Transition Metal Chemistry》1979,4(5):322-325
Summary
13C-n.m.r. spectra of (-SR)2Fe2(CO)6, (-SR)2Fe2(CO)5P(n-Bu)3 and (-X)2Fe2(CO)6 (X=S or Se) show that the solid state structure is maintained in solution. N.m.r. evidence indicates that two isomeric species, not separable by means of the usual physicochemical methods, are present for (-SPh)2Fe2(CO)6 with an overwhelming predominance of theanti form. The phosphine substitutes a COtrans to the iron-iron bond. For any of the iron chalcogen derivatives examined, variable temperature13C-n.m.r. spectra show that carbonyl exchange occur in one step. The energy barrier for the exchange of carbon monoxide in the phosphine derivative is lower than that in the unsubstituted complex. 相似文献
87.
Nanocrystalline CeO2 supplies reactive oxygen in the form of surface eta1 superoxide species and peroxide adspecies at the one-electron defect site to the supported active species of gold for the oxidation of CO. 相似文献
88.
89.
The kinetics of the interaction between molecular oxygen and the Co2+-complexes of the three terdentate ligands Z, N-(2-picolyl)-ethylenediamine (PEN), N-(2-picolyl)-oxamide (POA) and diethylenetriamine (DIEN) have been studied spectrophotometrically and using an O2 specific Clark electrode. Starting from the respective 1:1- and 1:2-complexes, the binuclear species ZCoO2(OH)CoZ and Z2CoO2CoZ2 are formed with each ligand. The existence of the former product shows that a minimum of three chelating nitrogen donors is sufficient to make a Co2+-complex reactive towards O2. As derived from the empirical rate laws the same general reaction mechanism must be valid for all three systems. In the case of PEN- and DIEN-complexes the oxygen adducts are metastable intermediates and formed in stoichiometric quantities. With POA irreversible formation of cobaltic species is rapid, and O2-adducts are present in steady state concentrations only, except in strongly basic solutions. 相似文献
90.