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101.
Vukadin M. Leovac Vladimir Divjaković Ana F. Petrović Nikolai V. Gerbeleu 《Monatshefte für Chemie / Chemical Monthly》1989,120(3):181-186
Summary The reaction of warmDMF solutions of Cu(II) perchlorate, 5-nitrosalicylaldehyde S-methylisothiosemicarbazone (H2
L) and piperidine (Pip) yielded the paramagnetic (eff=2.19 B.M.) Cu(L)Pip complex, whereL is the dianionic form of H2
L, formed as a result of deprotonation of the phenolic hydroxyl and NH2 group. Crystal data of the complex are: monoclinic P21,a=11.902(4),b=6.765(3),c=11.343(4)Å; =112.92°,V=841.20(8)Å3,M=400.9,Z=2,d
0=1.60 gcm–3,d
c
=1.58 gcm–3,F(000)=424. The structure was refined to a residualR=0.047. The copper(II) ion is coordinated in a square-planar arrangement by the piperidine nitrogen and the NNO set of donor atoms ofL.
Komplexe der Übergangsmetalle mit Thiosemicarbazid-Liganden, IV. Synthese und molekulare Struktur von 5-Nitrosalicylaldehyd-S-methylisothiosemicarbazonato-piperidin-kupfer(II)
Zusammenfassung Durch die Reaktion in warmenDMF-Lösungen von Cu(II) Perchlorat, 5-Nitrosalicylaldehyd-S-methylisothiosemicarbazon (H2 L) und Piperidin (Pip) wurde ein paramagnetischer Komplex (eff=2.19 B.M.) Cu(L)Pip erhalten, wobeiL nach doppelter Deprotonierung (NH2- und Phenolhydroxyl-Gruppe) als dianionische Form von H2 L vorliegt. Die kristallographischen Daten des Komplexes sind: monokline Raumgruppe P21,a=11.902(4),b=6.765(3),c=11.343(4)Å, =112.92°;V=841.20Å3,M=400.9,Z=2,d 0=1.60 gcm–3,d c =1.58 gcm–3,F(000)=424. Die struktur wurde bis zu einemR-Wert von 0.047 verfeinert. Die Koordination des Kupfers wird quadratisch-planar über den Piperidin-Stickstoff und die NNO-Donorhülle der Chelatliganden gebildet.相似文献
102.
Peña-Alvarez A Díaz L Medina A Labastida C Capella S Vera LE 《Journal of chromatography. A》2004,1027(1-2):131-136
Steam distillation (SD) extraction-solid-phase microextraction coupled to GC-MS was developed for the determination of terpenes and Bligh-Dyer extraction-derivatization coupled with GC for the determination of fatty acids such as ethyl esters were used. It was found that the three different Agave species have the same profile of fatty acids; the quantity of these compounds is different in each Agave variety. On the other hand, different terpenes were identified in the three Agave plants studied: nine in A. salmiana, eight in A. angustifolia and 32 in A. tequilana Weber var. azul. 相似文献
103.
104.
Santiago MB Vélez MM Borrero S Díaz A Casillas CA Hofmann C Guadalupe AR Colón JL 《Electroanalysis》2006,18(6):559-572
We present a carbon paste electrode (CPE) modified using the electron mediator bis(1,10‐phenanthroline‐5,6‐dione)(2,2′‐bipyridine)ruthenium(II) ([Ru(phend)2bpy]2+) exchanged into the inorganic layered material zirconium phosphate (ZrP). X‐Ray powder diffraction showed that the interlayer distance of ZrP increases upon [Ru(phend)2bpy]2+ intercalation from 10.3 Å to 14.2 Å. The UV‐vis and IR spectroscopies results showed the characteristic peaks expected for [Ru(phend)2bpy]2+. The UV‐vis spectrophotometric results indicate that the [Ru(phend)2bpy]2+ concentration inside the ZrP layers increased as a function of the loading level. The exchanged [Ru(phend)2bpy]2+ exhibited luminescence even at low concentration. Modified CPEs were constructed and analyzed using cyclic voltammetry. The intercalated mediator remained electroactive within the layers (E°′=–38.5 mV vs. Ag/AgCl, 3.5 M NaCl) and electrocatalysis of NADH oxidation was observed. The kinetics of the modified CPE shows a Michaelis–Menten behavior. This CPE was used for the oxidation of NADH in the presence of Bakers' yeast alcohol dehydrogenase. A calibration plot for ethanol is presented. 相似文献
105.
Mathematical Programming - We consider the capacitated cycle covering problem: given an undirected, complete graph G with metric edge lengths and demands on the vertices, we want to cover the... 相似文献
106.
Hair color changes and protein damage caused by ultraviolet radiation 总被引:12,自引:0,他引:12
Santos Nogueira AC Joekes I 《Journal of photochemistry and photobiology. B, Biology》2004,74(2-3):109-117
Ultraviolet and visible radiations are known to damage hair. However, quantitative data relating damage to hair type, proteins and color to the radiation wavelength are missing. We studied the effect of UV plus visible, UVA plus visible, visible mercury-vapor lamp radiation and sunlight on (blended) virgin dark-brown, blond and red hair and (one head) virgin black and curly dark-brown hair. All hair types showed a substantial increase in protein loss in water after lamp and sun irradiation. The damaging effect of UVB was about 2-5 times higher than that of UVA plus visible radiation, depending on the hair type. Significant color changes were also observed in every hair type, after lamp and sun irradiation, being more pronounced for the light colored hairs. The luminosity difference parameter was the major contributor to the hair color changes, but significant changes in the red-green and yellow-blue parameters of every hair were observed. In this case, the damaging effect is ascribable mainly to UVA radiation. No significant changes in the mechanical properties or topography were observed in any case. We discuss these results in terms of hair type and composition and melanin types. 相似文献
107.
Esteso Ana Alemany M. M. E. Ortiz Angel Liu Shaofeng 《Central European Journal of Operations Research》2022,30(3):1101-1127
Central European Journal of Operations Research - Agri-food production must increase while food waste needs to be reduced for improving the position of farmers. To do so it is necessary to... 相似文献
108.
Ana M. Vargas 《Rendiconti del Circolo Matematico di Palermo》1995,44(2):273-282
LetM
e
0
be the maximal operator over segments of length 1 with directions belonging to a Cantor set. It has been conjectured that
this operator is bounded onL
2. We consider a sequence of operators over finite sets of directions converging toM
e
0
. We improve the previous estimate for the (L
2,L
2)-norm of these particular operators. We also prove thatM
e
0
is bounded from some subsets ofL
2 toL
2. These subsets are composed of positive functions whose Fourier transforms have a very weak decay or are supported in a vertical
strip.
Partially supported by Spanish DGICYT grant no. PB90-0187. 相似文献
109.
LetEçS 1 be a set with Minkowski dimensiond(E)1. We consider the Hardy-Littlewood maximal function, the Hilbert transform and the maximal Hilbert transform along the directions ofE. The main result of this paper shows that these operators are bounded onL rad p (R2) forp>1+d(E) and unbounded whenp<1+d(E). We also give some end-point results. 相似文献
110.
Federico Sánchez-Bringas Ana Irene Ramírez-Galarza 《Annals of Global Analysis and Geometry》1995,13(2):129-140
LetM be a compact orientable surface,I:M R4 an immersion of classC
r
and
a normal unitary smooth vector field. We prove that in the space of pairs (I,
) the family of pairs all whose umbilical points are Darbouxian is generic. 相似文献