The intrinsic photoluminescence properties of hyperbranched polyethylenimines (PEIs) and their linear counterpart (LPEIs) have been studied in absence of any classical fluorescent probes. The comparison of the inherent fluorescence emission between hyperbranched polyethylenimines and their linear analogues demonstrates that linear polyamines are capable of producing strong intrinsic photoluminescence species having long excited lifetimes without need of having a tridimensional‐branched structure. The creation of inherently fluorescent polymeric centers from hyperbranched and linear polyethyleimines can be modulated by specific chemical modification and oxidation of amine groups as well as by adjusting the acidity of the polymer.
Inulosucrase (IslA) from Leuconostoc citreum CW28 belongs to a new subfamily of multidomain fructosyltransferases (FTFs), containing additional domains from glucosyltransferases.
It is not known what the function of the additional domains in this subfamily is. 相似文献
This review covers the state of the art of the analysis of real (or non-ideal) samples on microfluidic devices. A real sample analysis performed on microfluidics conceptually involves the complete integration of sample preparation, analyte separation, and detection on these platforms. Different “lab-on-a-chip” approaches have emerged in relevant application areas such as clinical, environmental, and food analysis which will be critically illustrated and discussed with respect to the strengths and weakness found. Likewise, the main challenges and perspectives will also be commented on. 相似文献
Reaction of Cl3SiR or (EtO)3SiR with [PW11O39]7− affords the disubstituted hybrid anions [PW11O39(SiR)2O]3−. These species have been characterized by IR spectroscopy in the solid state and by multinuclear NMR (1H, 29Si, 31P and 183W) and cyclic voltammetry in solution. The hydrosilylation of [PW11O39(Si-CHCH2)2O]3− has been achieved with Et3SiH and PhSiMe2H. These are the first examples of hydrosilylation on a hybrid tungstophosphate core. The chromogenic behaviour of hybrid species has been demonstrated in solution. 相似文献
Electron accepting Sc(3)N@C(80) promotes long-range charge transfer events evolving from photoexcited metalloporphyrins to afford radical ion pair states with lifetimes in the range of μs. 相似文献
The interaction of dimethyl- and diethyltin(IV) cations with methylpyridoxine iodide ([MePN]I; PN = pyridoxine) was studied in ethanol/water (80:20(v/v) containing Cl?, NO3? or I? ions in different molar ratios. Several compounds containing the deprotonated (MePN-H) or neutral (MePN) ligand were isolated and characterized by elemental analysis, IR and NMR (1H, 13C, 119Sn) spectroscopy and FAB mass spectrometry. The compounds [SnMe2(MePN-H)](I3), [SnEt2(MePN-H)](I3), [SnMe2(MePN-H)(NO3)], [SnEt2(MePN-H)(NO3)] and [SnMe2(MePN)2]I2 were studied by X-ray diffractometry. The compounds in which the MePN-H ligand is present can be described as containing dinuclear [SnR2(MePN-H)]22+ (R = Me, Et) units, in which two bridging chelating methylpyridoxinato ligands link two metal atoms. Interactions also exist between the metal and the I3? or NO3? anions and these interactions differ in degree and type. On the other hand, in the only example of a complex containing the MePN ligand, the mononuclear [SnMe2(MePN)2]2+ unit is present. The in vitro antitumor activity of these complexes against the HeLa, A2780 and A2780cis cell lines was determined and compared with that of the equivalent PN derivatives. 相似文献
One carbon atom is too many. Two subphthalocyanine-extended TTF electron donor-acceptor conjugates were synthesized and characterized. Their photophysical properties prompt the remarkable impact that one extra carbon between the two constitutents exerts on photoinduced processes, that is, charge recombination dynamics in the normal versus inverted region. 相似文献
We have studied the kinetics of polymeric nanoparticle formation for poly(styrene‐block‐4‐vinylpyridine) [P(S‐b‐4‐VPy)], chains in a non‐selective solvent using 1,4‐dibromobutane (DBB) as a cross‐linker by means of different nuclear magnetic resonance (NMR) spectroscopy techniques. The kinetic process was followed using 1H, 13C, and 2‐D Heteronuclear Single Quantum Correlation (HSQC) NMR experiments. The kinetic data obtained from 2‐D HSQC and 1H NMR experiments were in good agreement between them, proving the reliability of the 2‐D HSQC NMR technique for the in situ study of the kinetics of core‐shell nanoparticle formation. A value of 1.5 × 10−5 s−1 was determined for the apparent kinetic constant of the P(S‐b‐4‐VPy)‐DBB core‐shell nanoparticle formation process.
