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971.
Fanizzi FP Natile G Lanfranchi M Tiripicchio A Laschi F Zanello P 《Inorganic chemistry》1996,35(11):3173-3182
The effect of the phenanthroline substituents on the structure and reactivity of platinum(II) and platinum(IV) complexes has been investigated. The X-ray crystal structures of the compounds [PtI(2)(4,7-Ph(2)phen)].CHCl(3) (1dz.CHCl(3)), [PtI(4)(4,7-Ph(2)phen)].CHCl(3) (2dz.CHCl(3)), [PtI(2)(2,9-Me(2)-4,7-Ph(2)phen)] (1fz), and [PtI(4)(2,9-Me(2)-4,7-Ph(2)phen)].I(2) (2fz.I(2)) have shown that complexes 1fz and 2fz, containing ortho-substituted phenanthrolines, exhibit a remarkable displacement of the equatorial iodine atoms from the N-Pt-N' plane (average 0.477(2) and 0.199(2) ?, respectively), a bending of the phenanthroline [angle between outer rings of 19.9(7) and 14.2(7) degrees, respectively] and a rotation of the N-C-C'-N' plane with respect to the N-Pt-N' plane [32.3(10) and 26.5(9) degrees, respectively]. Comparison between the structures of 1fz and 2fz, both having the phenanthroline with methyl substituents in the ortho position, indicates that, in the latter case, because of the presence of the two axial iodine ligands, the displacements of the ligands from the equatorial plane are smaller and find a compensation in a narrowing of the I(1)-Pt-I(1') angle (5 degrees ) and a lengthening of the Pt-N bonds (0.07 ?). The electrochemical behavior of the four-coordinate platinum(II) complexes shows that compounds possessing regular planar geometry have access to the one-electron reduced species, whereas those with distorted coordination geometry are irreversibly reduced by collapsing of the complex geometry. This is in sharp contrast with the behavior of related nickel complexes for which the pseudo-tetrahedral coordination imposed by bulky 2,9-substituents of phenanthroline stabilizes the nickel(I) species. Spectroscopic results allow us to assign a significant Pt(I) character to [1d](-) monoanions. The electrogenerated, plus one electron, complexes are not indefinitely stable and, because of conjugation with the phen ligand, progressively restore the Pt(II) oxidation state by transferring the electron to the peripheral organic ligand. The latter process can involve multiple electron additions in the macroelectrolysis time scale. The related platinum(IV) complexes [PtX(4)(L)] undergo irreversible two-electron reduction accompanied by fast release of the axial ligands and formation of the corresponding platinum(II) species. 相似文献
972.
A multiconfigurational self-consistent field method based on the concept of generalized active space (GAS) is presented. GAS wave functions are obtained by defining an arbitrary number of active spaces with arbitrary occupation constraints. By a suitable choice of the GAS spaces, numerous ineffective configurations present in a large complete active space (CAS) can be removed, while keeping the important ones in the CI space. As a consequence, the GAS self-consistent field approach retains the accuracy of the CAS self-consistent field (CASSCF) ansatz and, at the same time, can deal with larger active spaces, which would be unaffordable at the CASSCF level. Test calculations on the Gd atom, Gd(2) molecule, and oxoMn(salen) complex are presented. They show that GAS wave functions achieve the same accuracy as CAS wave functions on systems that would be prohibitive at the CAS level. 相似文献
973.
Sabrina Moret Susi Cherubin Maria Teresa Rodriguez-Estrada Giovanni Lercker 《Journal of separation science》1994,17(12):827-830
This work suggests an HPLC method for qualitative and quantitative determination of Nε(2-amino-2-carboxyethyl)-L -lysine (LAL). LAL was released from total hydrolysates of various proteins of animal origin and derivatized with dansyl chloride. The performance of two different columns, Spherisorb 3S TG and μ-Bondapack C18, was compared; better resolution and quantitative response were obtained with the former. The mobile phase was a mixture of 0.01 M phosphate buffer (pH 7) and acetonitrile. Linear response and quantitative repeatability were tested for both detectors used (UV-Vis set at 254 nm; fluorimetric set at λex(max) = 360 nm and λem(max) = 525 nm). For LAL standard the minimum detectable amount was 0.05 ng, whereas for LAL in actual samples the amount was 0.5 ng (40 μg/g of analyzed proteins). Good analytical repeatability was obtained, resulting in CV % of 4.7 and 3.8 for UV and fluorimetric detectors, respectively. LAL recovery was determined using both detectors; the values obtained were 94 % (fluorimetric) and 92 % (UV). Greater noise levels were observed with the fluorimetric detector and its higher sensitivity could not, therefore, be fully utilized. The highest amounts of LAL were found in the casein (2816 μg/g) and cooked albumin (615 μg/g) samples. 相似文献
974.
Giovanni Cerioni Maria Teresa Cocco Cenzo Congiu Antonio Maccioni 《Journal of heterocyclic chemistry》1981,18(7):1379-1382
A synthesis of 1-aminoimidazoles by reaction between α-halogenoketones and N-acetylamidrazones is described. Structure and position of substituent groups in the synthesized aminoimidazoles were established by spectroscopical methods. 相似文献
975.
A straightforward procedure for the preparation of nucleoside analogue 1 and its regioisomer 2 containing a dihydro-1,4-dithiin as sugar moiety has been accomplished in four steps by our readily available heterocyclic system 5. Nucleobase insertion was carried out by direct addition of N4-acetylcytosine to sulfoxide derivatives via Pummerer-type glycosidation reaction. 相似文献
976.
Roddaro S Pellegrini V Beltram F Biasiol G Sorba L Raimondi R Vignale G 《Physical review letters》2003,90(4):046805
Remarkable nonlinearities in the differential tunneling conductance between fractional quantum Hall edge states at a constriction are observed in the weak-backscattering regime. In the nu=1/3 state a peak develops as temperature is increased and its width is determined by the fractional charge. In the range 2/3=nu=1/3 this width displays a symmetric behavior around nu=1/2. We discuss the consistency of these results with available theoretical predictions for interedge quasiparticle tunneling in the weak-backscattering regime. 相似文献
977.
Giovanni Forni 《Annali di Matematica Pura ed Applicata》1991,159(1):229-254
Summary In this paper we give an elementary proof of basic vanishing properties for homology and cohomology with compact supports of q-complete spaces which follow from the results of H.Hamm [16], [17] and K.-H.Fieseler-L.Kaup [13]. At the same time we obtain new finiteness results for the homology and the cohomology with compact supports in the q-convex case, which is not treated in [16], [17] and [13]. Our work extends to general q-complete spaces recent papers of M.Coltoiu-N.Mihalache [8] and M.Coltoiu [7] which treated the case of Stein spaces (q=0). A typical result is the following: if X is a q-complete space of dimension n, then Hi (X, Z)=0 for i>n+q and Hn+q (X, Z) is free, if X is also purely dimensional and locally a set-theoretic complete intersection, then H
c
i
(X, Z)=0 for ic
n
–q(X, Z) is free. The vanishing of the cohomology with compact supports for q-complete spaces has as consequence Lefschetz-type theorems for singular spaces (the homology statements) proved by C.Okonek [24] using Goresky-MacPherson stratified Morse theory. 相似文献
978.
This work is partially supported by MPI, 40%. The second author thanks the Department of Mathematics of the University of
Trento for its kind hospitality during the preparation of this paper. 相似文献
979.
Weak minimizers,minimizers and variational inequalities for set-valued functions. A blooming wreath?
Giovanni P. Crespi 《Optimization》2017,66(12):1973-1989
Recently, necessary and sufficient conditions in terms of variational inequalities have been introduced to characterize minimizers of convex set-valued functions. Similar results have been proved for a weaker concept of minimizers and weaker variational inequalities. The implications are proved using scalarization techniques that eventually provide original problems, not fully equivalent to the set-valued counterparts. Therefore, we try, in the course of this note, to close the network among the various notions proposed. More specifically, we prove that a minimizer is always a weak minimizer, and a solution to the stronger variational inequality always also a solution to the weak variational inequality of the same type. As a special case, we obtain a complete characterization of efficiency and weak efficiency in vector optimization by set-valued variational inequalities and their scalarizations. Indeed, this might eventually prove the usefulness of the set optimization approach to renew the study of vector optimization. 相似文献
980.
Drug Delivery: Biodegradable Passion Fruit‐Like Nano‐Architectures as Carriers for Cisplatin Prodrug (Part. Part. Syst. Charact. 11/2016) 下载免费PDF全文