16034-43-8Relevant articles and documents
Catalytic deuteration of C(sp2)-H bonds of substituted (Hetero)arenes in a Pt(II) CNN-pincer complex/2,2,2Trifluoroethanol-d1 system: Effect of substituents on the reaction rate and selectivity
Kramer, Morgan,Watts, David,Vedernikov, Andrei N.
supporting information, p. 4102 - 4114 (2020/11/30)
Thirty four (hetero)arene derivatives have been tested in catalytic H/D exchange reactions involving their C(sp2)- H bonds and 2,2,2-trifluoroethanol-d1 (TFE-d1) in the presence of the homogeneous Pt(II) complex 1 supported by a sulfonated CNN-pincer ligand at 80 °C. The 18 substrates, including one pharmaceutical (naproxen), that are stable in the presence of 1 and are active in the H/D exchange reaction have been characterized by their position-specific extent of deuteration and, in a number of cases, the reaction kinetic selectivity. For the most reactive substrates the extent of deuteration approaches the expected statistical distribution of the exchangeable H and D atoms: e.g., 67-69% for phenol after 23 h and 88% for indole β-CH bonds after 45 min. For a few substrates (N,N-dimethylaniline, indole, nitrobenzene) the H/D exchange is highly position selective. No satisfactory correlation was found between the position-specific (meta, para) H/D exchange rate constants for X-monosubstituted benzenes and Hammett σX constants. This observation was proposed to be related to the concerted nature of the CH bond activation, the rate-determining CH bond oxidative addition at a Pt(II) center. A novel scale of Hammett σMX constants was introduced to characterize the reactivity of C(sp2)-H bonds in transition-metal-mediated reactions. The experimentally determined position-specific Gibbs energies of activation of the H/D exchange in substituted benzenes (meta and para positions) as well as in thiophene (α and β positions) were matched satisfactorily using DFT calculations.
Chemical pressure effect by selective deuteration in the molecular-based conductor, 2,5-dimethyl-N,N'-dicyano-p-benzoquinone immine-copper salt, (DMe-DCNQI)2Cu
Aonuma, Shuji,Sawa, Hiroshi,Kato, Reizo
, p. 1541 - 1550 (2007/10/02)
The mixed-valence copper salt of DMe-DCNQI91, where DMe-DCNQI=2,5-dimethyl-N,N'-dicyano-p-benzoquinone diimine) is a molecular conductor whose electrical and magnetic properties are quite sensitive to pressure.We have performed selective deuteriation of the molecule 1.By control of the position and number of deuterium atoms, the low-pressure region (ca. 500 bar) in the pressure-temperature phase diagram of (1)2Cu was reproduced at ambient pressure.The equivalency of the deuteriation and pressure effects is explained from steric origins; 'contraction' aroused by the slightly shorter C-D bond (steric isotope effect) and 'constriction' by pressure.
The Radical Ions of 4,5,7,8-Tetramethylparacyclophane
Bruhin, Juerg,Gerson, Fabian,Ohya-Nishiguchi, Hiroaki
, p. 1045 - 1050 (2007/10/02)
By the use of strong oxidising and reducing agents, 4,5,7,8-tetramethylparacyclophane (II) has been converted to its radical cation (II+.) and to its radical anion (II-.).These radical ions, as well as those generated from the 1