Engineering an iridium-containing metal–organic molecular capsule for induced-fit geometrical conversion and dual catalysis

2016 ◽  
Vol 52 (62) ◽  
pp. 9628-9631 ◽  
Author(s):  
Xuezhao Li ◽  
Jinguo Wu ◽  
Liyong Chen ◽  
Xiaoming Zhong ◽  
Cheng He ◽  
...  
Keyword(s):  
Cooperative Binding ◽  
Induced Fit ◽  
Molecular Capsule ◽  
Metal Organic ◽  
Dual Catalysis ◽  
Carbonate Anion

Quantitative dynamic capsule–capsule conversion by cooperative binding one carbonate anion and switchable dual catalysis was achieved within an Ir2Co3-type capsule.

scholarly journals Cooperative Binding and Stepwise Encapsulation of Drug Molecules by Sulfonylcalixarene-Based Metal-Organic Supercontainers

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2656
Author(s):  
Tian-Pu Sheng ◽  
Xin-Xia Fan ◽  
Guo-Zong Zheng ◽  
Feng-Rong Dai ◽  
Zhong-Ning Chen
Keyword(s):  
Chloroform Solution ◽  
Hill Equation ◽  
Cooperative Binding ◽  
Synthetic Receptors ◽  
Guest Molecules ◽  
Binding Behavior ◽  
Drug Molecules ◽  
Titration Curves ◽  
Metal Organic ◽  
Titration Technique

The cooperative binding behavior of a face-directed octahedral metal-organic supercontainer featuring one endo cavity and six exo cavities was thoroughly examined in chloroform solution through ultraviolet-visible (UV-Vis) titration technique using two representative drug molecules as the guests. The titration curves and their nonlinear fit to Hill equation strongly suggest the efficient encapsulation of the guest molecules by the synthetic host, which exhibit interesting cooperative and stepwise binding behavior. Based on the control experiments using tetranuclear complex as a reference, it is clear that two equivalents of the guest molecules are initially encapsulated inside the endo cavity, followed by the trapping of six additional equivalents of the drug molecules through six exo cavities (1 eq. per exo cavity), and the remaining guests are entrapped by the external pockets. The results provide an in-depth understanding of the cooperative binding behavior of metal-organic supercontainers, which opens up new opportunities for designing synthetic receptors for truly biomimetic functional applications.

scholarly journals Mechanics of allostery: contrasting the induced fit and population shift scenarios

2019 ◽  
Author(s):  
Riccardo Ravasio ◽  
Solange Flatt ◽  
Le Yan ◽  
Stefano Zamuner ◽  
Carolina Brito ◽  
...  
Keyword(s):  
Proper Function ◽  
Cooperative Binding ◽  
Induced Fit ◽  
Data Set ◽  
Elastic Mode ◽  
Allosteric Proteins ◽  
Protein Size ◽  
Distant Location ◽  
Population Shift ◽  
Optimal Stiffness

In allosteric proteins, binding a ligand can affect function at a distant location, for example by changing the binding affinity of a substrate at the active site. The induced fit and population shift models, which differ by the assumed number of stable configurations, explain such cooperative binding from a thermodynamic viewpoint. Yet, understanding what mechanical principles constrain these models remains a challenge. Here we provide an empirical study on 34 proteins supporting the idea that allosteric conformational change generally occurs along a soft elastic mode presenting extended regions of high shear. We argue, based on a detailed analysis of how the energy profile along such a mode depends on binding, that in the induced fit scenario there is an optimal stiffness for cooperative binding, where N is the number of residues involved in the allosteric response. We find that the population shift scenario is more robust to mutation affecting stiffness, as binding becomes more and more cooperative with stiffness up to the same characteristic value , beyond which cooperativity saturates instead of decaying. We confirm numerically these findings in a non-linear mechanical model. Dynamical considerations suggest that a stiffness of order is favorable in that scenario as well, supporting that for proper function proteins must evolve a functional elastic mode that is softer as their size increases. In consistency with this view, we find a significant anticorrelation between the stiffness of the allosteric response and protein size in our data set.

The role of metal–organic porous frameworks in dual catalysis

2021 ◽  
Author(s):  
Kayhaneh Berijani ◽  
Ali Morsali
Keyword(s):  
Metal Organic Frameworks ◽  
Crystalline Solids ◽  
Metal Organic ◽  
Dual Catalysis ◽  
Inorganic And Organic

Metal–organic frameworks (MOFs) are a valuable group of porous crystalline solids with inorganic and organic parts that can be used in dual catalysis.

scholarly journals Triplet Dynamic Nuclear Polarization of Guest Molecules through Induced Fit in a Flexible Metal-Organic Framework

2021 ◽  
Author(s):  
Saiya Fujiwara ◽  
Naoto Matsumoto ◽  
Koki Nishimura ◽  
Nobuo Kimizuka ◽  
Kenichiro Tateishi ◽  
...  
Keyword(s):  
Dynamic Nuclear Polarization ◽  
Room Temperature ◽  
Nuclear Polarization ◽  
Metal Organic Framework ◽  
Induced Fit ◽  
Guest Molecules ◽  
Metal Organic ◽  
Target Molecules ◽  
Flexible Metal ◽  
Organic Framework

Dynamic nuclear polarization utilizing photoexcited triplet electrons (triplet-DNP) has great potential for room-temperature hyperpolarization of nuclear spins. However, the polarization transfer to molecules of interest remains a challenge due to the fast spin relaxation and weak interaction with target molecules at room temperature in conventional host materials. Here, we demonstrate the first example of DNP of guest molecules in a porous material at around room temperature by utilizing the induced-fit-type structural transformation of a crystalline yet flexible metal-organic framework (MOF). In contrast to the usual hosts, 1H spin-lattice relaxation time becomes longer by accommodating a pharmaceutical model target 5-fluorouracil as the flexible MOF changes its structure upon guest accommodation to maximize the host-guest interactions. Combined with triplet-DNP and cross-polarization, this system realizes an enhanced 19F-NMR signal of guest target molecules at around room temperature.

scholarly journals Adaptive self-assembly and induced-fit transformations of anion-binding metal-organic macrocycles

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Ting Zhang ◽  
Li-Peng Zhou ◽  
Xiao-Qing Guo ◽  
Li-Xuan Cai ◽  
Qing-Fu Sun
Keyword(s):  
Self Assembly ◽  
Anion Binding ◽  
Induced Fit ◽  
Metal Organic

scholarly journals Enhanced Gas Uptake in a Microporous Metal–Organic Framework via a Sorbate Induced-Fit Mechanism

2019 ◽  
Vol 141 (44) ◽  
pp. 17703-17712 ◽  
Author(s):  
Mei-Hui Yu ◽  
Brian Space ◽  
Douglas Franz ◽  
Wei Zhou ◽  
Chaohui He ◽  
...  
Keyword(s):  
Metal Organic Framework ◽  
Induced Fit ◽  
Gas Uptake ◽  
Metal Organic ◽  
Organic Framework

Electron microscope characterization of MOCVD-grown gap layers on Si

1986 ◽  
Vol 44 ◽  
pp. 724-725
Author(s):  
K.M. Jones ◽  
M.M. Al-Jassim ◽  
J.M. Olson
Keyword(s):  
Atmospheric Pressure ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Lattice Match ◽  
Si Substrates ◽  
Metal Organic ◽  
Good Lattice ◽  
Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

Structural and electronic properties of defects in semiconductors

1995 ◽  
Vol 53 ◽  
pp. 4-5
Author(s):  
J.L. Batstone
Keyword(s):  
Semiconductor Device ◽  
Chemical Vapor ◽  
Misfit Strain ◽  
Organic Chemical ◽  
Extended Defects ◽  
Transmission Electron ◽  
Semiconductor Thin Films ◽  
Wide Range ◽  
Metal Organic ◽  
Film Substrate

The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

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