Abstract:Cyclodextrins are widely used cyclic oligosaccharides of D-glucose whose hydrophilic exterior is covered by hydroxyl groups and whose hydrophobic interior is surrounded by lipophilic moieties. Because of this structural feature,...
“…21b ). Although the formation of ( 1 ) 6 by a dual interaction system can be deemed “crystallization-driven self-assembly” 31 – 38 , the resultant assembly based on the dual interaction system is completely different from any previous examples, even among PDA-based coordination macrocycles 39 , 40 . Fig.…”
Self-complementary assembly is one of the most promising phenomena for the formation of discrete assemblies, e.g., proteins and capsids. However, self-complementary assembly based on multiple host-guest systems has been scarcely reported due to the difficulty in controlling each assembly. Herein, we report a dual interaction system in which the key assembly direction is well regulated by both π-π stacking and hydrogen bonding to construct a self-complementary macrocycle. Continuous host-guest behavior of anthracene-based molecular tweezers during crystallization leads to successful construction of a cyclic hexamer, which is reminiscent of Kekulé’s monkey model. Furthermore, the cyclic hexamer in a tight and triple-layered fashion shows hierarchical assembly into cuboctahedron and rhombohedral assemblies in the presence of trifluoroacetic acid. Our findings would be potentially one of metal-free strategies for constructing anthracene-based supramolecular assemblies with higher-order structure.
“…21b ). Although the formation of ( 1 ) 6 by a dual interaction system can be deemed “crystallization-driven self-assembly” 31 – 38 , the resultant assembly based on the dual interaction system is completely different from any previous examples, even among PDA-based coordination macrocycles 39 , 40 . Fig.…”
Self-complementary assembly is one of the most promising phenomena for the formation of discrete assemblies, e.g., proteins and capsids. However, self-complementary assembly based on multiple host-guest systems has been scarcely reported due to the difficulty in controlling each assembly. Herein, we report a dual interaction system in which the key assembly direction is well regulated by both π-π stacking and hydrogen bonding to construct a self-complementary macrocycle. Continuous host-guest behavior of anthracene-based molecular tweezers during crystallization leads to successful construction of a cyclic hexamer, which is reminiscent of Kekulé’s monkey model. Furthermore, the cyclic hexamer in a tight and triple-layered fashion shows hierarchical assembly into cuboctahedron and rhombohedral assemblies in the presence of trifluoroacetic acid. Our findings would be potentially one of metal-free strategies for constructing anthracene-based supramolecular assemblies with higher-order structure.
“…The starting complex Na 3 [Au 3 Co 2 ( d -pen) 6 ]·13H 2 O (Na 3 [ 1 ])) was prepared according to a procedure described in the literature. , …”
Section: Methodsmentioning
confidence: 99%
“…30% in a solvent-mediated crystal-to-crystal transformation manner, induced by the coordination of COO – groups of [ 1 ] 3– to aqua Co II species. Encouraged by this finding, we started to investigate the reactions of [ 1 ] 3– with other metal species in water. − While the use of Zn 2+ and [M(phen) 2 (H 2 O) 2 ] 2+ (M = Co 2+ , Ni 2+ , Mn 2+ , Zn 2+ ; phen = 1,10-phenanthroline) gave different 1D PCISs with lower porosities, , 3D PCISs analogous to 2 Co , [Ni(H 2 O) 6 ] 3 [ 1 ] 2 ( 2 Ni ) and [Mn(H 2 O) 6 ] 3 [ 1 ] 2 ( 2 Mn ), were obtained by using Ni 2+ and Mn 2+ , respectively. In this article, we report the synthesis and structural characterization of 2 Ni and 2 Mn , which undergo similar two-step crystal-to-crystal transformations (Scheme ).…”
Treatment of Na3[Au3Co2(d-pen)6] (Na3[1]; d-H2pen = d-penicillamine)
with M(OAc)2 (M
= NiII, MnII) in water gave ionic crystals of
[M(H2O)6]3[1]2 (2
M
) in which [1]3– anions are hydrogen-bonded with [M(H2O)6]2+ cations to form a 3D porous framework
with a porosity of ca. 80%. Soaking crystals of 2
Ni
in its mother liquor afforded crystals of [Ni(H2O)6]2[{Ni(H2O)4}(1)2] (3
Ni
) in which [1]3– anions are
connected to trans-[Ni(H2O)4]2+ and [Ni(H2O)6]2+ cations
through coordination and hydrogen bonds, respectively, to form a 1D
porous framework with a porosity ca. 60%. Further soaking crystals
led to [{Ni(H2O)4}3(1)2] (4
Ni
), in which
[1]3– anions are connected to cis-[Ni(H2O)4]2+ and trans-[Ni(H2O)4]2+ cations
through coordination bonds in a dense framework with a porosity of
ca. 30%. A similar two-step crystal-to-crystal transformation mediated
by solvent proceeded when crystals of 2
Mn
were soaked in a mother liquor. However, the transformation
of 2
Mn
generated [{Mn(H2O)4}(H1)] (4′
Mn
) as the final product, in which [H1]2– anions are connected to cis-[Mn(H2O)4]2+ cations through coordination
bonds in a very dense framework with a porosity ca. 5% by way of [Mn(H2O)6]2[{Mn(H2O)4}(1)2] (3
Mn
), which is isostructural with 3
Ni
. While all the compounds adsorbed H2O and CO2 depending on the degree of their porosity, unusually large
NH3 adsorption capacities were observed for 4
Ni
and 4′
Mn
, which have dense frameworks.
“…Cyclodextrin molecules have a hydrophobic inner cavity, while the outer side and the port are hydrophilic [ 44 , 45 , 46 ]. Cyclodextrin inclusion complexes are compounds formed by one or more suitable guest molecules that enter the cavity of cyclodextrin in whole or in part through non-covalent bonds (such as hydrophobic interactions) [ 47 , 48 ]. The hydrophobic cavity of cyclodextrin has the ability to include small molecules, oligonucleotides, proteins, and other compounds [ 49 , 50 , 51 ].…”
The clinical use of anticancer drugs necessitates new technologies for their safe, sensitive, and selective detection. In this article, lanthanide (Eu3+ and Tb3+)-loaded γ-cyclodextrin nano-aggregates (ECA and TCA) are reported, which sensitively detects the anticancer drug irinotecan by fluorescence intensity changes. Fluorescent lanthanide (Eu3+ and Tb3+) complexes exhibit high fluorescence intensity, narrow and distinct emission bands, long fluorescence lifetime, and insensitivity to photobleaching. However, these lanthanide (Eu3+ and Tb3+) complexes are essentially hydrophobic, toxic, and non-biocompatible. Lanthanide (Eu3+ and Tb3+) complexes were loaded into naturally hydrophilic γ-cyclodextrin to form fluorescent nano-aggregates. The biological nontoxicity and cytocompatibility of ECA and TCA fluorescent nanoparticles were demonstrated by cytotoxicity experiments. The ECA and TCA fluorescence nanosensors can detect irinotecan selectively and sensitively through the change of fluorescence intensity, with detection limits of 6.80 μM and 2.89 μM, respectively. ECA can safely detect irinotecan in the cellular environment, while TCA can detect irinotecan intracellularly and is suitable for cell labeling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
