Inclusion studies for metal-organic open-frameworks, [Ni(C10}H24N4)(H2O)2]3[BTC]2·24H2O (1) and [Ni(C10H26N6)]3 [BTC]2·18H2O(2) (BTC3- = 1,3,5-benzenetricarboxylate) with various organic andinorganic guest molecules have been carried out. 1 is the previously reportedmolecular floral lace with 1-D channels, where positively charged macrocyclic layersand negatively charged BTC3- layers are alternately packed by hydrogen bondinginteractions. 2 is assembled in this study from nickel(II) hexaazamacrocyclic complexcontaining methyl pendant arms and BTC3-. The X-ray structure of 2 shows thatthe nickel(II) complex and BTC3- form a 2-D coordination polymer. The XRPD patternsof 2 indicate that framework of 2 is slightly deformed upon removal of waterguest molecules but restored upon rebinding of water. The host solid 1 binds MeOHin toluene, and 1,3,5-trihydroxybenzene (THB) and 4-hydroxyacetophenone (HAP) in EtOH/toluene (v/v = 1/4) solutions. The binding constants (Kf) of 1 forMeOH, THB, and HAP are 66.4 M-1, 259 M-1, and 13.9 M-1,respectively. In the range of high concentration of the guest, however, the host showsvarious binding curves depending upon the types of guest. It binds PhOH in toluene,showing a sigmoid curve. It also binds transition metal complexes such as[Cu(NH3)4](ClO4)2, [Cu(ethylenediamine)2](ClO4)2,[Cu(histamine)2](ClO4)2, and[Cu(N,N'-bis(3-aminopropyl)ethylenediamine)](ClO4)2 in MeCN, with Kf values of 645 M-1, 9.52 M-1, 37.2 M-1, and 6.00 M-1,respectively. The host solid 2 binds selectively PhOH over PhCl and PhBr, showing that hydrogen bonding interaction between the host and guest plays an important role in the selectivity. 相似文献
The title compound, C14H16N4O8S4, has crystallographic C2 symmetry with half a molecule in the asymmetric unit and a dihedral angle of 58.7 (1)° between the two planar 1,3,4‐thiadiazole five‐membered rings of the macrocyclic, giving the molecule a twisted conformation. 相似文献
In the title compound, C29H30N6, the naphthyridine ring is almost planar with a dihedral angle of 5.4 (1)° between the pyridyl rings. The dihedral angles between the naphthyridine system and the diethylaminophenyl, phenyl and pyrrolidine rings are 53.1 (1), 19.8 (1) and 20.9 (1)°, respectively. The pyrrolidine ring adopts a half‐chair conformation. The molecule is stabilized by weak C—H?N interactions. 相似文献
In the crystal structure of the title compound, 4‐cyano‐N‐(4‐methoxybenzylidene)phenylamine N‐oxide, C15H12N2O2, the 4‐methoxyphenyl is approximately coplanar with the nitrone moiety but significantly rotated with respect to the 4‐cyanophenyl moiety. The extent of this rotation is significantly different for the two crystallographically independent molecules of the asymmetric unit [dihedral angles of 19.4 (1) and 26.5 (1)°]. The geometry about the C=N bond is Z. The two molecules are related to one another by a pseudo inversion centre. 相似文献
The title compound, (S)‐(+)‐4‐[5‐(2‐oxo‐4,5‐dihydroimidazol‐1‐ylsulfonyl)indolin‐1‐ylcarbonyl]anilinium chloride (S)‐(+)‐1‐[1‐(4‐aminobenzoyl)indoline‐5‐sulfonyl]‐4‐phenyl‐4,5‐dihydroimidazol‐2‐one, C24H23N4O4S+·Cl?·C24H22N4O4S, crystallizes in space group C2 from a CH3OH/CH2Cl2 solution. In the crystal structure, there are two different conformers with their terminal C6 aromatic rings mutually oriented at angles of 67.69 (14) and 61.16 (15)°. The distances of the terminal N atoms (of the two conformers) from the chloride ion are 3.110 (4) and 3.502 (4) Å. There are eight distinct hydrogen bonds, i.e. four N—H?Cl, three N—H?O and one N—H?N, with one N—H group involved in a bifurcated hydrogen bond with two acceptors sharing the H atom. C—H?O contacts assist in the overall hydrogen‐bonding process. 相似文献
We construct torus bundles over locally symmetric varieties associated to cocycles in the cohomology group , where Γ is a discrete subgroup of a semisimple Lie group and L is a lattice in a real vector space. We prove that such a torus bundle has a canonical complex structure and that the space
of holomorphic forms of the highest degree on a fiber product of such bundles is isomorphic to the space of mixed automorphic
forms of a certain type.
(Received 4 September 1998) 相似文献
An improved deep submicrometer (0.25 μm) MOSFET radio-frequency (RF) large signal model that incorporates a new breakdown current model and drain-to-substrate nonlinear coupling was developed and investigated using various experiments. An accurate breakdown model is required for deep submicrometer MOSFETs due to their relatively low breakdown voltage. For the first time, this RF nonlinear model incorporates the breakdown voltage turnover trend into a continuously differentiable channel current model and a new nonlinear coupling circuit between the drain and the lossy substrate. The robustness of the model is verified with measured pulsed I-V, S-parameters, power characteristics, harmonic distortion, and intermodulation distortion levels at different input and output termination conditions, operating biases, and frequencies 相似文献
Summary: This communication describes an enzyme stabilization method that allows the use of enzymes irrespective of environmental factors, especially heat, while maintaining their activity for a long time. We have designed enzyme microcapsules that consist of papain enzyme cores, poly(propylene glycol) interlayers, and poly(ε‐caprolactone) walls. By confocal laser scanning microscopy measurements and the thermal stability of papain‐loaded microcapsules, it is demonstrated that the papain is surrounded by a hydrophobic polyol layer and stabilized by the exclusive volume effect. In our study, improved thermal stability can be obtained by using more hydrophobic long‐chained polyols, which is understood to be attributed to the effective formation of a hydrophobic polyol layer between the papain and the polymer wall by means of conformational anchoring in the interface.
(A) A CLSM image of a PCL microcapsule containing FITC‐labeled papain and RBITC‐labeled PPG at the same time. (B) A scheme of the role of hydrophobic polyols in the interface of enzyme and polymer. 相似文献
In this paper, we propose a new MAC protocol, called proxy relay-enabled MAC (PR-MAC), to improve the capacity of multi-rate WLANs. PR-MAC introduces a new entity called Proxy Relay Point (PRP), which serves as a relay between the AP and stations. The cooperation of the AP with PRP replaces direct transmissions for low-rate stations with fast two-hop transmissions while the stations think that they communicate directly with the AP. Our experiment and simulation results showed that PR-MAC can significantly improve the throughput of legacy stations without any modification on the MAC operation of the stations. 相似文献
Single-crystalline CdTe(133) films have been grown by metalorganic chemical vapor deposition on Si(211) substrates. We studied
the effect of various growth parameters on the surface morphology and structural quality of CdTe films. Proper oxide removal
from the Si substrate is considered to be the principal factor that influences both the morphology and epitaxial quality of
the CdTe films. In order to obtain single-crystalline CdTe(133) films, a two-stage growth method was used, i.e., a low-temperature
buffer layer step and a high- temperature growth step. Even when the low-temperature buffer layer shows polycrystalline structure,
the overgrown layer shows single-crystalline structure. During the subsequent high-temperature growth, two-dimensional crystallites
grow faster than other, randomly distributed crystallites in the buffer layer. This is because the capturing of adatoms by
steps occurs more easily due to increased adatom mobility. From the viewpoint of crystallographic orientation, it is assumed
that the surface structure of Si(211) consists of (111) terrace and (100) step planes with an interplanar angle of 54.8°.
This surface structure may provide many preferable nucleation sites for adatoms compared with nominally flat Si(100) or (111)
surfaces. The surface morphology of the resulting films shows macroscopic rectangular-shaped terrace—step structures that
are considered to be a (111) terrace with two {112} step planes directed toward 〈110〉. 相似文献