Unexpected formation of aryl-cyanides during the oxidative decomposition of aryl-cyanocuprates. Transfer of a non-transferable group?

Oxidative decomposition of cyanocuprates of the type CuLi(CN)Ar (Ar = [C6H4(CH2NMe2)-2]-, 1a) or type CuLi2(CN)Ar2(1b) shows the unexpected formation of aryl-cyanides in up to 30% yield. © 2002 Elsevier Science Ltd. All rights reserved

Copper(I) thiolate catalysts in asymmetric conjugate addition reactions

Full conversion and enantioselectivities up to 83% have been obtained in the conjugate addition reactions of diethyl zinc to Michael acceptors catalyzed by well-defined (chiral) copper(I) aminoarenethiolates. Interesting differences between organozinc or Grignard reagents have been found: for cyclic enones R(2)Zn reagents afford better results, whereas earlier work showed that RMgX reagents react more selectively with acyclic enones

Synthesis of Cyclopentadienyl-based Tricarbonyl Rhenium Complexes and some Unusual Reactivities of Cp-substituents

Cyclopentadienyl-based (Cp-based) tricarbonyl rhenium complexes [Cp′Re(CO)3] are convenient precursors for the corresponding Cp-based trioxorhenium complexes (Cp′ReO3), which are potential catalysts for the deoxydehydration (DODH) of diols to olefins. To evaluate the influence of different Cp substituents in Cp′ReO3 complexes in DODH, a series of alkyl-substituted Cp′Re(CO)3 complexes (1a–8a) were synthesized. High yields (86–98 %) were obtained from the reactions of Re2(CO)10 with the corresponding Cp′H ligands (1–8). The C–O infrared absorptions of 1a–8a indicate that the electron-donating character of the Cp ligand increases with the number of substituents attached directly to the Cp ring. Analogous aryl-substituted complexes 10a–12a containing bulky phenyl groups were accessed through the salt metathesis of ReBr(CO)5 with the lithium salt of the deprotonated ligand (Cp′Li), and the aryl groups decreased the electron donation. Furthermore, an unusual [6+4] cycloaddition reaction of (CpMe4H)Re(CO)3 (8a) with excess ligand resulted in the highly asymmetric Cp′Re(CO)3 complex 9a. Finally, the reaction of the tetraphenylcyclopentadienone ligand with Re2(CO)10 was investigated and led to the isolation of two unusual compounds, namely, Re(CO)3 complexes of the Shvo-type hydroxytetraphenylcyclopentadienyl ligand, [Ph4Cp(OH)]Re(CO)3 (13a), and a benzofuran-fused cyclopentadienyl ligand, [Ph3Cp(C6H4O)]Re(CO)3 (14a). X-ray crystal structures were obtained for the new Cp′Re(CO)3 complexes (CptBu2H3)Re(CO)3 (2a), [1,2,3-Me3(tetrahydroindenyl)]Re(CO)3 (7a), 9a, 13a, and 14a, which all have the typical three-legged “piano-stool” configuration

Luminescent colloidal InSb quantum dots from in situ generated single-source precursor

Despite recent advances, the synthesis of colloidal InSb quantum dots (QDs) remains underdeveloped, mostly due to the lack of suitable precursors. In this work, we use Lewis acid-base interactions between Sb(III) and In(III) species formed at room temperature in situ from commercially available compounds (viz., InCl3, Sb[NMe2]3 and a primary alkylamine) to obtain InSb adduct complexes. These complexes are successfully used as precursors for the synthesis of colloidal InSb QDs ranging from 2.8 to 18.2 nm in diameter by fast coreduction at sufficiently high temperatures (≥230 °C). Our findings allow us to propose a formation mechanism for the QDs synthesized in our work, which is based on a nonclassical nucleation event, followed by aggregative growth. This yields ensembles with multimodal size distributions, which can be fractionated in subensembles with relatively narrow polydispersity by postsynthetic size fractionation. InSb QDs with diameters below 7.0 nm have the zinc blende crystal structure, while ensembles of larger QDs (≥10 nm) consist of a mixture of wurtzite and zinc blende QDs. The QDs exhibit photoluminescence with small Stokes shifts and short radiative lifetimes, implying that the emission is due to band-edge recombination and that the direct nature of the bandgap of bulk InSb is preserved in InSb QDs. Finally, we constructed a sizing curve correlating the peak position of the lowest energy absorption transition with the QD diameters, which shows that the band gap of colloidal InSb QDs increases with size reduction following a 1/d dependence