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We present a compact experimental realization of the interaction among five field modes in a chi(2) nonlinear crystal. The classical evolution of the fields can be analytically described assuming that two of the fields play the role of nondepleted pumps. If one of the fields has a nonzero input amplitude, then the other two fields at the output are holographic replicas of the input signal. 相似文献
303.
Iridoids from seeds of Gentiana lutea 总被引:1,自引:0,他引:1
In the seeds of Gentiana lutea L. there were also detected, in addition to the known sweroside and getiopicroside, loganic acid 3 and trifloroside 4 that is present as main glycosidic component. The structures of 3 and 4 were established by spectroscopic studies. 相似文献
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We prove some asymptotic characterizations for the subsolutions to a class of diffusion equations on homogeneous Lie groups. These results are the diffusion counterpart of the classical Blaschke, Privaloff, Reade and Saks Theorems for harmonic functions. 相似文献
307.
Albertin G Antoniutti S Bacchi A Celebrin A Pelizzi G Zanardo G 《Dalton transactions (Cambridge, England : 2003)》2007,(6):661-668
Azide complexes [M(RN(3))(CO)(3)P(2)]BPh(4)[M = Mn, Re; R = C(6)H(5)CH(2), 4-CH(3)C(6)H(4)CH(2), C(6)H(5), 4-CH(3)C(6)H(4), C(5)H(9); P = PPh(OEt)(2), PPh(2)(OEt)] were prepared by allowing tricarbonyl MH(CO)(3)P(2) hydride complexes to react first with Br?nsted acid (HBF(4), CF(3)SO(3)H) and then with organic azide in the dark. In sunlight the reaction yielded tetraazabutadiene [M(eta(2)-1,4-R(2)N(4))(CO)(2)P(2)]BPh(4) complexes or, with benzyl azide, imine [M{eta(1)-NH[double bond, length as m-dash]C(H)Ar}(CO)(3)P(2)]BPh(4)(Ar = C(6)H(5), 4-CH(3)C(6)H(4)) derivatives. Tetraazabutadiene [M(eta(2)-1,4-R(2)N(4))(CO)(2)P(2)]BPh(4) complexes were also prepared by reacting dicarbonyl MH(CO)(2)P(3) species first with Br?nsted acid and then with an excess of organic azide. Complexes were characterised spectroscopically (IR, (1)H, (31)P, (13)C, (15)N NMR data) and by the X-ray crystal structure determination of complex [Re{eta(2)-1,4-(C(6)H(5)CH(2))(2)N(4)}(CO)(2){PPh(OEt)(2)}(2)]BPh(4)(). Strong evidence for coordination of the organic azide was obtained from the (15)N NMR spectra of labelled [M(C(6)H(5)CH(2)(15)NN(15)N)(CO)(3)P(2)]BPh(4) derivatives. 相似文献
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309.
Two dimensional (2D) homonuclear 1H J-resolved (JRES) nuclear magnetic resonance spectroscopy is increasingly used in metabolomics. This approach visualises metabolite chemical shifts and scalar couplings along different spectral dimensions, thereby increasing peak dispersion and facilitating spectral assignments and accurate quantification. Here, we optimise the processing of 2D JRES spectra by evaluating different window functions, a traditional sine-bell (SINE) and a combined sine-bell-exponential (SEM) function. Furthermore, we evaluate different projection methods for generating 1D projected spectra (pJRES). Spectra were recorded from three disparate types of biological samples and evaluated in terms of sensitivity, reproducibility and resolution. Overall, the SEM window function yielded considerably higher sensitivity and comparable spectral reproducibility and resolution compared to SINE, for both 1D pJRES and 2D JRES datasets. Furthermore, for pJRES spectra, the highest spectral quality was obtained using SEM combined with skyline projection. These improvements lend further support to utilising 2D J-resolved spectroscopy in metabolomics. 相似文献
310.
Dr. Yang Liu Mikaël Le Roch Alessia Mori Dr. Alexandre Pradal Prof. Dr. Giovanni Poli Dr. Julie Oble 《European journal of organic chemistry》2023,26(38):e202300710
The significance of cross dehydrogenative couplings has increased considerably in recent years. This article revisits the [3+2] C−C/N−C, C−C/O−C and C−C/C−C annulation strategy, recently reported by our group, according to a Pd(II) catalyzed dehydrogenative variant. Our original report relied on Pd(0) catalysis, using α,β-unsaturated-γ-oxy carbonyls as bis-electrophiles and resonance-stabilized acetamides or 3-oxoglutarates as C/N and O/C or C/C bis-nucleophiles, respectively. In this more modern and straightforward Pd(II)-catalyzed dehydrogenative approach, β,γ-unsaturated carbonyl derivatives replace α,β-unsaturated-γ-oxy carbonyls as bis-electrophiles. Our study includes experimental optimization and showcases the synthetic versatility in the formation of diverse heterocyclic structures, such as bicyclic lactams, furo-cycloalkanones and bicycloalkane-diones. Furthermore, a mechanism is proposed to elucidate the underlying processes involved in these reactions. 相似文献