نتایج جستجو برای: r sulfonatocalix4 arene
تعداد نتایج: 449633 فیلتر نتایج به سال:
The rhodium(III)-catalyzed hydroarylation of internal alkynes is described. Good yields are obtained for a variety of alkynes, and excellent regioselectivity is observed for unsymmetrically substituted alkynes. The reaction also gives good yields for a range of arenes. Preliminary mechanistic investigations suggest that this reaction proceeds through arene metalation with the cationic rhodium c...
In the title compound, C(32)H(27)N(3)O, the fused tetra-cycilc ring system is essentially planar [r.m.s. deviation = 0.07 (7) Å]. An intra-molecular N-H⋯π(arene) inter-action and a weak intra-molecular C-H⋯N hydrogen bond may influence the mol-ecular conformation. In the crystal, weak inter-molecular C-H⋯N hydrogen bonds link the mol-ecules into centrosymmetric dimers, forming R(2) (2)(14) moti...
The title thia-calix[4]arene derivative, C(36)H(34)Br(2)O(8)S(4), adopts an unusual pinched cone conformation with the prop-oxy-substituted benzene rings inclined inward [forming a dihedral angle of 33.4 (1)°] and with the brominated benzene rings bent outward, making a dihedral angle of 66.1 (1)°. In the crystal, the mol-ecules form chains along [001] via C-H⋯S hydrogen bonds and S⋯S contacts ...
The title compound, C(19)H(12)F(2)N(2)O(2), a 2:1 product of the reaction of 3-fluoro-benzoyl-chloride and 2-amino-pyridine crystallizes with a disordered 3-fluoro-benzene ring adopting two conformations [ratio of occupancies 0.959 (4):0.041 (4)]. In the crystal structure, there are no classical hydrogen bonds and inter-actions comprise C-H⋯O in the form 2(C-H)⋯O=C [with motif R(2) (1)(5)]; C-H...
The beginning of the 21st century has seen tremendous growth in the field of decarboxylative activation. Benzoic acid derivatives are now recognised as atom-economic alternatives to traditional cross-coupling partners, and they also benefit from being inexpensive, readily available and shelf-stable reagents. In this microreview we discuss recent developments in the coupling of benzoic acid deri...
The tricarbonylchromium unit bound to the arene ring of the chiral title complex, [Cr(C(19)H(26)O(3))(CO)(3)], is rotated by ca 25 degrees in agreement with the proposed mechanism for 1,5-asymmetric induction of nucleophilic attack.
An efficient method for the C4-regiocontrolled C-H functionalization of coumarins to enable facile oxidative cross-couplings with simple arene components is disclosed.
a new cesium ion selective pvc membrane based on parent calix [4] arene was developed for potentiometric determination of cesium in environmental samples. the electrode based on p-5,11,17,23tetra(tertbutyl) 25,26,27,28-tetrahydroxy calix[4]arene(thc) as ionophor ,dibutyl phthalate (dbp)as plasticizer ,sodium tetra phenyl borate(natpb)and oleic acid as lipophilic salt and additive showed the ...
Nickel hydrides supported by a terphenyl diphosphine were synthesized and found to undergo nickel-to-arene H-transfers. Some of the resulting complexes also undergo the reverse (C-to-Ni) H-migration, indicating the potential for storing H-equivalents in this type of pincer ligand. NMR spectroscopy, single crystal X-ray diffraction, and isotopic labeling studies investigating the mechanism of th...
A cage-shaped N,N'-diacylaminal crystallizes from some aromatic solvents as "supramolecular chair cyclohexanes", squat cylindrical hexamers with approximate D3d symmetry containing two arene molecules, and from other aromatic and nonaromatic solvents as infinite tapes. A homologous diacylaminal crystallizes only as an infinite tape. The hexamers represent the first examples of cyclic hexamers h...
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