Synthesis, characterization, and C—N bond cleavage of tungsten(VI)arylimido-calix[4]arene complexes

2001 ◽  
Vol 79 (5-6) ◽  
pp. 463-471
Author(s):  
Martyn Brown ◽  
Chet Jablonski
Keyword(s):  
Reaction Mechanism ◽  
Good Yield ◽  
Bond Cleavage ◽  
Aliphatic Amines ◽  
Arene Complexes ◽  
Cone Conformation ◽  
Arene Derivative ◽  
Tert Butyl ◽  
Arene Complex

The tetradentate, partially flattened cone tungsten(VI) imido-calix[4]arene derivative [W(NC6H5)(t-BucalixH)]+Cl–, (4), is formed in good yield from reaction of p-tert-butyl-calix[4]arene (t-BucalixH4), and W(NC6H5)Cl4. A reaction mechanism involving a putative, bidentate calixarene intermediate W(NC6H5)(t-BucalixH2)Cl2 (3), which partitions by reversible cleavage of the imido group to give the known tetradentate calixarene complex W(t-Bucalix)Cl2 (2), and elimination of HCl to form the thermodynamic imido product 4 is proposed. A series of iso structural [W(NAr)(t-BucalixH)]+Cl– (Ar = C6H5 or o,m,p-C6H4CH3) imido derivatives (4–7), which adopt a partially flattened cone conformation in solution has been prepared by reaction of dichloride 2 with H2NAr (Ar = C6H5, o,m,p-C6H4CH3). Reaction of W(t-Bucalix)Cl2 with aliphatic amines affords a red product formulated as the nitrido complex, 9, which results from facile cleavage of the imido C—N bond.Key words: calix[4]arene complex, imido complex, nitrido complex, C—N bond cleavage, conformation, metallocalixarene.

Synthesis of Doubly Azacrowned Thiacalixarenes

2005 ◽  
Vol 2005 (4) ◽  
pp. 240-241 ◽  
Author(s):  
Yan Jin ◽  
Xiong Li ◽  
Shuling Gong ◽  
Yuanyin Chen
Keyword(s):  
Good Yield ◽  
Cone Conformation ◽  
Tert Butyl

Under selected conditions, 1,2:3,4-doubly crowned p-tert-butyl-thiacalix[4]arene in cone conformation and 1,3:2, 4-doubly crowned p-tert-butyl-thiacalix[4]arene in 1,3-alternate conformation were obtained through aminolysis in high to good yield, respectively.

Palladium-Catalyzed Desulfurative Hiyama Coupling of Thioureas to Achieve Amides via Selective C–N Bond Cleavage

Synthesis ◽  
2021 ◽  
Author(s):  
Zhuo Zeng ◽  
Zhanyu He ◽  
Chu Yan ◽  
Mei Zhang ◽  
Majeed Irfan ◽  
...  
Keyword(s):  
Good Yield ◽  
Bond Cleavage ◽  
New Approach ◽  
Mild Conditions ◽  
Palladium Catalyzed

AbstractPalladium-catalyzed Hiyama coupling of active thioureas via selective C–N bond cleavage is reported. Notably, the new approach employed active thioureas as coupling partners in the presence of arylsilanes to give amides in good yield. Further, this strategy, which utilized CuF2 as a key oxidant and activator, afforded various amide products under mild conditions and an easy to handle procedure without extra base.

tert-Butyl(3-cyano-4,6-dimethylpyridin-2-yl)carbonate as a green and chemoselective N-tert-butoxycarbonylation reagent

2019 ◽  
Vol 43 (17) ◽  
pp. 6549-6554
Author(s):  
Fangyu Du ◽  
Qifan Zhou ◽  
Yang Fu ◽  
Hanqi Zhao ◽  
Yuanguang Chen ◽  
...  
Keyword(s):  
Aliphatic Amines ◽  
Tert Butyl ◽  
Aromatic And Aliphatic Amines

The use of tert-butyl(3-cyano-4,6-dimethylpyridin-2yl) carbonate as a chemoselective tert-butoxycarbonylation reagent for aromatic and aliphatic amines has been demonstrated (30 examples).

scholarly journals Unveiling the formation 1 : 2 supramolecular complexes between cucurbit[7]uril and a cationic calix[4]arene derivative

2019 ◽  
Vol 55 (92) ◽  
pp. 13828-13831 ◽  
Author(s):  
Márcia Pessêgo ◽  
Johan Mendoza ◽  
José Paulo da Silva ◽  
Nuno Basílio ◽  
Luis Garcia-Rio
Keyword(s):  
Isothermal Titration Calorimetry ◽  
Supramolecular Complexes ◽  
Titration Calorimetry ◽  
Cone Conformation ◽  
Arene Derivative ◽  
Esi Ms ◽  
H Nmr ◽  
Dosy Nmr

The formation of host–guest complexes between cucurbit[7]uril (CB7) and a tetracationic calix[4]arene derivative in the so-called cone conformation was investigated by 1H NMR, DOSY NMR, isothermal titration calorimetry and ESI-MS.

Product distributions and isotopic selectivities in ir multiphoton dissociation of pentafluoroiodoethane

1981 ◽  
Vol 59 (9) ◽  
pp. 1307-1310 ◽  
Author(s):  
E. Weinberg ◽  
M. Gauthier ◽  
P. A. Hackett ◽  
C. Willis
Keyword(s):  
Reaction Mechanism ◽  
Bond Cleavage ◽  
Thermal Dissociation ◽  
Infrared Multiphoton Dissociation ◽  
High Fluence ◽  
Reaction Products ◽  
Product Distributions ◽  
Multiphoton Dissociation

Infrared multiphoton dissociation of pentafluoroiodoethane leads to a complex array of reaction products. For photolysis in the v4 band the reaction mechanism involves C2F5—I bond cleavage followed by thermal dissociation of C2F5 radicals. For irradiation within the v3 band at high fluence, efficient secondary photolysis of C2F5 radicals is postulated. At lower fluences the dissociation is isotopically selective leading to C4F10 enriched in carbon-13.

Synthesis of 1-Alkyl-3-(2-oxo-2-aryl/alkyl-ethyl)indolin-2-ones through Gold/Brønsted Acid Relay Actions: Observation of Selective C=C Bond Cleavage of Enaminones

Synthesis ◽  
2017 ◽  
Vol 49 (16) ◽  
pp. 3609-3618 ◽  
Author(s):  
Yanzhong Li ◽  
Yulei Zhao ◽  
Yang Yuan ◽  
Lingkai Kong ◽  
Fangfang Zhang
Keyword(s):  
Reaction Mechanism ◽  
Bond Cleavage ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Reaction Conditions ◽  
One Pot ◽  
Esi Ms ◽  
Ms Analysis ◽  
Brönsted Acid

A novel gold(I)/Brønsted acid sequential catalyzed/promoted procedure to synthesize 1-alkyl-3-(2-oxo-2-aryl/alkyl-ethyl)indolin-2-ones under mild reaction conditions is developed. This methodology is realized by relay actions of gold and a Brønsted acid in a one-pot multistep manner. The gold(I)-catalyzed chemoselective C(sp2)-H functionalization of enaminones and Brønsted acid promoted cleavage of the C=C bond are integrated effectively. Based on the results of control experiments and ESI-MS analysis, a possible reaction mechanism is proposed.

Binap and MeO-Biphep complexes of Ru(II). Dicationic ligands as 6e donors. Unexpected cyclometallation in connection with P—C bond breaking

2001 ◽  
Vol 79 (5-6) ◽  
pp. 693-704
Author(s):  
Carolien J den Reijer ◽  
Pascal Dotta ◽  
Paul S Pregosin ◽  
Alberto Albinati
Keyword(s):  
Chemical Shifts ◽  
Bond Cleavage ◽  
Bond Breaking ◽  
Arene Complexes ◽  
Nmr Studies ◽  
Bonding Mode ◽  
C Nmr

A series of cationic and dicationic Ru-arene complexes with Binap (1a) and MeO-Biphep (1b) have been prepared. 13C NMR studies are shown to be useful in connection with recognising the 6e-bonding mode of 1a and 1b in the dications [Ru(1a or 1b)(η6-arene)](SbF6)2 (8,9). Reaction of 8,9 with: (a) (Bu4N)(Ph3SiF2) leads to a cyclometallated product which arises via P—C bond breaking and P—F bond making; (b) methanol provides a straightforward synthesis of the corresponding hydrides. 13C NMR p-cymene chemical shifts are reported.Key words: P—C bond cleavage, 6e donors, cyclometallation, hydrides, 13C NMR.

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