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91.
Scolaro LM Plutino MR Romeo A Romeo R Ricciardi G Belviso S Albinati A 《Dalton transactions (Cambridge, England : 2003)》2006,(21):2551-2559
Reactions of the cationic complex ions [PtMe(Me2SO)(PP)]+ (PP = dppf (1,1'-bis(diphenylphosphino)ferrocene) and dppe (1,2-bis(diphenylphosphino)ethane)) with 5,10,15,20-tetrakis(4-pyridyl)-21H,23H-porphyrin (TpyP) led to the formation of the symmetrical tetraplatinated porphyrin complexes, [PtMe(PP)]4TpyP.X4 (PP = dppf, X = CF3SO3-, 3, and PP = dppe, X = BF4-, 5) containing the organometallic fragment [PtMe(PP)]. The precursor sulfoxide platinum complexes [PtMe(Me2SO)(dppf)]CF3SO3, 2 and [PtMe(Me2SO)(dppe)]BF4, 4, were prepared by halide abstraction from [PtMeCl(dppf)], 1, and by controlled protonolysis of [PtMe2(dppe)] respectively, in the presence of a small amount of dimethyl sulfoxide. All these starting platinum(II) compounds, as well as the porphyrin derivatives 3 and 5, were fully characterized through elemental analysis, 1H NMR mono- and bidimensional, 31P[1H], 31P-1H HMBC, UV/Vis absorption and photophysical measurements. The X-ray crystal structure of complex 1 has been determined. In order to ascertain the electronic influence of ferrocene, the spectroscopic and redox properties of 3 were compared with those of TPyP and of the analogous 5. Cyclic voltammetry (CV), differential pulse voltammetry (DPV), 1H and 31P NMR data, and UV/Vis data, all suggest a certain degree of communication between the central porphyrin and the peripheral hetero-bimetallic fragments. In contrast, no detectable interaction among these peripheral groups seem to come into play. Unlikely from the porphyrin derivative 5, formation of well defined fluorescent mesoscopic ring structures was easily achieved by simple evaporation from diluted dichloromethane solutions of 3. 相似文献
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95.
Barreca ML Gitto R Quartarone S De Luca L De Sarro G Chimirri A 《Journal of chemical information and computer sciences》2003,43(2):651-655
A three-dimensional pharmacophore model for the binding of noncompetitive AMPA receptor antagonists was developed in order to map common structural features of highly active compounds. This hypothesis, which consists of two hydrophobic regions, one hydrogen bond acceptor and one aromatic region, was successfully used as framework for the design of a new class of allosteric modulators containing a tetrahydroisoquinoline skeleton and for in silico screening. The promising biological results suggested that the identified molecules might be useful "lead compounds" for future drug development. 相似文献
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97.
Cunsolo V Foti S La Rosa C Saletti R Canters GW Verbeet MP 《Journal of mass spectrometry : JMS》2003,38(5):502-509
An electrospray ionisation (ESI) mass spectrometric method for the determination of the equilibrium constant and free energy (DeltaG) of protein unfolding was used to monitor the denaturation process at different pH of three metallo-proteins, i.e. wild-type copper azurin, zinc azurin and wild-type amicyanin. The time course of the unfolding process was followed by dissolving the proteins under denaturing conditions (methanol-water (1 : 1, v/v)) at different pH (2.5, 3.0, 3.5) and recording ESI spectra at time intervals. The spectra showed two series of peaks, corresponding to the native holo-protein and the unfolded apo-protein. From the intensity ratio of these two series of peaks at increasing time and at equilibrium, the equilibrium constants for the unfolding process for the three proteins could be determined. From these equilibrium constants a DeltaG degrees derivation was attempted. The DeltaG degrees values obtained decrease with decrease in pH, in agreement with the expected reduction of conformational stability of proteins at lower pH. The results obtained confirm that ESI-MS can be used for monitoring of unfolding process and to derive quantitative thermodynamic data. 相似文献
98.
Salvatore Foti Rosaria Saletti Filippo Russo Andrea Santagati Maria Santagati 《Journal of mass spectrometry : JMS》1989,24(6):379-384
The electron-impact-induced fragmentation of eleven 1,3,4-thiadiazolo[3,2-a][1,3,5]triazines was investigated with the aid of exact mass measurements, B/E and B2/E linked scans, and deuterated compounds. The dominating breakdown process in the electron impact mass spectra of 2-substituted 6-phenyl-1,3,4-thiadiazolo[3,2-a]-[1,3,5]triazine-5,7-diones (1–5) is a retro-Diels-Alder reaction. This process gives rise to the base peak, whereas the molecular ions are of very low intensity. In the mass spectra of 2-substituted 7-methylthio-1,3,4-thiadiazolo-[3,2-a][1,3,5]triazine-5-ones (6–11) in which this fragmentation cannot occur because of the two conjugated double bonds in the triazine ring, the molecular ions are very intense. The mass spectral data permits an unequivocal structure assignment to these compounds, which are otherwise difficult to characterize. 相似文献
99.
Bazzicalupi C Bencini A Bianchi A Duce C Fornasari P Giorgi C Paoletti P Pardini R Rosaria Tinè M Valtancoli B 《Dalton transactions (Cambridge, England : 2003)》2004,(3):463-469
The coordination properties of the ditopic oxa-aza macrocycles L1-L3 toward Ni(II) and Co(II) have been investigated by means of potentiometric and UV-vis spectrophotometric measurements. L1-L3 contain two triamine and/or tetraamine chains separated by two dioxa chains and form both mono- and dinuclear complexes in aqueous solution. In the [ML]2+ complexes, the metal ion is coordinated by one of the two polyamine moieties, while the other does not participate in the coordination. In the dinuclear complexes each metal ion is coordinated, almost independently, to a single polyamine moiety. Under aerobic conditions the binuclear Co(II) complexes of the ligands L1-L3 are able to bind molecular oxygen, with a bridging coordination of O2 between the two metals. 相似文献
100.
Rosaria Ciajolo Mohamud A. Jama Angela Tuzi Aldo Vitagliano 《Journal of organometallic chemistry》1985,295(2):233-238
The complex η5-[Pd(CH2CHCMeCH2CH2CHCMe2)-(MeCN)](BF4), a model for a key intermediate in diene polymerization, crystallizes in the monoclinic space group P21/c, a 11.362(2), b 13.655(4), c 10.046(2) Å, β 134.80(1)°. The structure was solved by conventional Patterson and Fourier syntheses and refined by full matrix least squares techniques to a final discrepancy index R = 0.058 for 1710 independent reflections. The palladium and nitrogen atoms, the center of gravity of the allyl triangle, and the middle point of the coordinated double bond are coplanar. The side chain of the organic moiety is located in the syn position with respect to the η3-allyl group. The orientation of the coordinated double bond, which forms an angle of 26° with the coordination plane, is novel for palladium(II) complexes. 相似文献