نتایج جستجو برای: macrocycle
تعداد نتایج: 1399 فیلتر نتایج به سال:
Reaction of 4-tert-butyl-2,6-diformylphenol with (1R,2R)- or (1S,2S)-1,2-diaminocyclohexane in the presence of 1 equivalent of Zn(2+) ions leads to selective formation of a chiral 2+2 macrocycle. Application of 0.5 equivalent of Zn(2+) ions under the same conditions leads to selective formation of a chiral 3+3 macrocycle, which forms a cavitand-shaped trinuclear double-decker complex with Zn(II).
We describe an efficient methodology which allows for the preparation of a macrocycle incorporating a free coordination site. It is based on a transition metal-templated strategy and RCM to provide access to a Cu(I)-complexed [2]catenane consisting of the desired cyclised compound and a cleavable ring. Release of the cleavable ring leads to the formation of the target macrocycle in quantitative...
In the title compound, C(16)H(28)N(4)O(8)·2H(2)O, the 12-membered macrocycle has twofold crystallographic symmetry and the asymmetric unit comprises one half-mol-ecule. The four carbox-yl/carboxyl-ate groups reside on the same side of the macrocycle. The mol-ecule is a double zwitterion with two of the carb-oxy-lic acid H atoms transferred to the two N atoms on the opposite sides of the macrocy...
Computational simulations of macrocycle-encapsulated single-walled carbon nanotubes (SWNTs) and C60 are reported. A molecular mechanical force field method has been used to calculate the physical properties of these complexes. The calculation shows that the macrocycle-encapsulated SWNTs and C60 are more stable than free SWNTs and C60. When macrocycles are bound to SWNTs, energetically stable we...
The title compound, (NH4)2[Zn(NCS)4]·2C12H24O6·H2O, the result of the reaction of ammonium thio-cyanate, 18-crown-6 and zinc(II) chloride in aqueous solution, exhibits an unusual supra-molecular structure. The Zn atom, two of the thio-cyanate chains and a water mol-ecule, disordered over two positions, lie on a mirror plane. The macrocycle adopts a conformation with approximate D 3d symmetry. T...
A metal template approach affords in high yield a tetra-Zn(salphen) macrocycle (3) which shows strong and cooperative self-assembly mediated by the formation of Zn(salphen) dimer units held together via μ(2)-phenoxo interactions. A cooperative binding mode for the tetranuclear Zn(4) macrocycle 3 is supported by comparison of UV-vis and fluorescence titration data recorded for 3 when compared wi...
We describe the design and synthesis of a novel functionality-rich, homochiral macrocycle, possessing the overall molecular D2 symmetry, in which multivalency is introduced into the covalent framework by means of four suitably positioned pyridine moieties. The macrocycle synthesis is carried out with functionalized, enantiopure 1,1'-binaphthyl synthons as the source of chirality by means of a r...
Advances in macrocycle-based membranes: molecular recognition, fabrication strategies, applications, perspectives, and future challenges.
A 14-membered macrocycle with an allene and a furan strategically located at across the ring from each other is synthesized using an allene ring closing metathesis reaction. Upon treatment of the macrocycle with a catalytic amount of Pd(OAc)(2) and other additives, the first transannular [4+3] cycloaddition occurred to yield 37% of a tetracyclic compound containing the ABC ring structure of the...
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