排序方式: 共有90条查询结果,搜索用时 10 毫秒
1.
Biswas P Panja SS Manogaran S Chakraborty T 《The journal of physical chemistry. A》2005,109(14):3225-3234
Laser-induced fluorescence excitation and resolved fluorescence spectra following excitations of the single vibronic levels (SVL) of p-vinyltoluene (p-VT) and p-vinylfluorobenzene (p-VFB) have been measured in a seeded supersonic free-jet expansion. A complete vibronic assignment of the fluorescence spectrum measured following excitation of the 0(0)0-band of p-VT has been presented. Normal vibrational modes in the S0 and S1 states of the molecule have been calculated by CASSCF method, and the correlation between the two set of modes is made by expressing the excited-state normal modes in terms of those of the ground state. The calculations predict that in the excited state methyl and vinyl torsional motions of p-VT are extensively mixed with many of the out-of-plane modes of the aromatic ring. Our resolved fluorescence spectral data measured following SVL excitations essentially agree with such predictions. In the excited state, the molecule exhibits a dramatically low threshold for the rotor-induced IVR in a supersonic jet expansion. Several mechanisms have been discussed to explain the phenomenon. 相似文献
2.
3.
G.K. Surya Prakash Laxman Gurung Philipp Christoph SchmidFang Wang Tisa Elizabeth ThomasChiradeep Panja Thomas MathewGeorge A. Olah 《Tetrahedron letters》2014
Nitroso compounds are versatile reagents in synthetic organic chemistry. Herein, we disclose a feasible protocol for the ipso-nitrosation of aryl boronic acids using chlorotrimethylsilane–sodium nitrite unison as nitrosation reagent system. 相似文献
4.
Subir Panja Debasish kundu Sabir Ahammed Brindaban C. Ranu 《Tetrahedron letters》2017,58(35):3457-3460
A highly chemoselective reduction of aryl, heteroaryl, acyl and sulfonyl azides to the corresponding amines has been achieved by Fe(0) nanoparticles in water at room temperature in the absence of external hydride source. Several readily reducible functionalities including alkene, alkyne, S-S linkage, OTBDMS remain unaffected during reduction. 相似文献
5.
Sisir Lohar Arnab Banerjee Animesh Sahana Sukanya Panja Ipsit Hauli Subhra Kanti Mukhopadhyay Debasis Das 《Tetrahedron letters》2014
Visible light excitable rhodamine B derivative (TARDHD) has been developed for fluorescence and naked eye detection of histidine in aqueous medium. TARDHD shows 45 fold fluorescence enhancement in the presence of histidine. It forms Schiff base with histidine and stabilizes via intra-molecular H-bonding. TARDHD can efficiently detect intracellular histidine. 相似文献
6.
Santanu Panja 《印度化学会志》2022,99(3):100359
Supramolecular gels formed by the self-assembly of organic molecules are useful in many areas from materials to medicine. Of the different applications, exploitation of gels for the visual detection of analytes is a fairly recent trend in gel chemistry. Most of the gel-based sensors rely on non-covalent interactions between the gelator molecules and the added chemical analytes and therefore, often suffer from less selectivity and long response time. In this context, dosimetric gelator probes are superior to other gel-based sensors with high selectivity and fast response time. Unlike non-covalent binding sites, dosimetric gelators typically contain a reaction centre and undergo a specific chemical reaction selective to an analyte resulting in either formation or rupturing of covalent bonds. In this review, we provide an up-to-date report of various reaction-based gel systems applied for the sensing of analytes. We elaborately discuss the concept, design principles, self-assembly properties, and reaction mechanisms of such gelators. We also highlight the limitations, challenges, and the necessity of further exploration of dosimetric gels in this domain. 相似文献
7.
M.M. Panja 《Applied mathematics and computation》2011,218(8):4147-4151
This note is concerned with an efficient computation of integrals of products of a smooth function and Daubechies scale function with partial support by using a one-point quadrature rule. The error estimate is obtained. The rule is illustrated by considering an example from the literature. 相似文献
8.
A rigorous derivation of the optical theorem (OT) from the conservation of probability flux (CPF) is presented for scattering
on an arbitrary spherically symmetric potential inN-spatial dimensions (ND). The constructed expression for the OT is found to yield the corresponding well-known results for
two- and three-dimensional cases in a rather natural way. The Aharonov-Bohm (AB) effect is considered as a scattering event
of an electron by a magnetic field confined in an infinitely long shielded solenoid and a similar derivation is attempted
for an appropriate optical theorem. Our current understanding of the scattering theory is found to be inadequate for the purpose.
The reason for this is discussed in some detail. 相似文献
9.
Transmission of forces in static granular materials is studied within the framework of the force network ensemble, by numerically evaluating the mechanical response of hexagonal packings of frictionless grains and rectangular packings of frictional grains. In both cases, close to the point of application of the overload, the response is nonlinear and displays two peaks, while at larger length scales, it is linear and elasticlike. The crossover between these two behaviors occurs at a depth that increases with the magnitude of the overload and decreases with increasing friction. 相似文献
10.
Mixing small molecule gelators is a promising route to prepare useful and exciting materials that cannot be accessed from any of the individual components. Here, we describe pH-triggered hydrogelation by mixing of two non-gelling amphiphiles. The intermolecular interactions among the molecules can be tuned either by controlling the degree of ionization of the components or by a preparative pathway, which enables us to control material properties such as gel strength, gel stiffness, thermal stability, and an unusual shrinking/swelling behaviour.The properties of a charge complementary multicomponent gel can be tuned either by pH change or by varying the preparative pathway. 相似文献