[Cu(C₆Cl₂F₃)(tht)]₄: An Extremely Efficient Catalyst for the Aryl Scrambling between Palladium Complexes

Abstract

The copper compound [Cu(C6Cl2F3)(tht)]4 (1) (tht: tetrahydrothiophene) is an excellent catalyst for the trans-to cis-isomerization of complexes [PdAr2(tht)2](Ar: fluoroaryl) and also for the exchange of aryls between those palladium complexes. Herein, we also communicate the synthesis and characterization of 1, and some of its derivatives. The x-ray structure of 1 shows a linear chain of copper atoms, supported by fluoroaryl rings. The NMR 19 F-DOSY study indicates that this structure is preserved in solution although in equilibrium with other species. ASSOCIATED CONTENT Supporting Information. The supporting information contains: Experimental and computational methods (11 pages). This material is available free of charge via the Internet at http://pubs.acs.org AUTHOR INFORMATION

Dynamic Au–C σ-Bonds Leading to an Efficient Synthesis of [n]Cycloparaphenylenes (n = 9 – 15) by a Self-Assembly

“…There were several reports on the exchange reaction of M-C σ-bonds (M = Pt(II), Pd(II), Au(I) etc.) (See supporting Scheme S2b) 63,64 65-69 70-73 74 , and the reactions were generally regarded as a slow process compared to that of the non-covalent metalligand bonds, i.e. Pd-N 1 and Pt-N 2 bonds (See supporting Scheme S2a).…”

Experimental and DFT Study of the [AuAr(AsPh3)]-Catalyzed cis/trans Isomerization of [PdAr2(AsPh3)2] (Ar = C6F5 or C6Cl2F3): Alternative Mechanisms and Its Switch upon Pt for Pd Substitution

“…Since that seminal study, a number of complexes have been reported for systems with M = Pd II , Pt II and M' = Au I , Ag I , Cu I , [4][5][6][7][8][9][10][11][12] containing Pd-Au interactions that resemble, more or less closely, the M-M' interactions proposed in reference 1 for the intermediates or transition states shown in Scheme 1. It might look far-fetched to think that the exchange (and isomerization) model based on formation of M-M' interactions at short distances could be found for less similar metal centers, but the fact is that in our theoretical mechanistic studies on the ZnMe2-catalyzed cis/trans isomerization of [PdMeAr(PR3)2] complexes (Ar = C6Cl2F3 and C6F5) we found Zn II playing a structural role quite similar to that of Au I in Scheme 1.…”

“…The M-C-M' angle (whether in intermediates or in transition states (TS) can vary from close to 90° to much smaller. In the last years, many examples of coupling reactions involving R-for-X Pd/Au transmetalations have been reported, in which organogold complexes participate as stoichiometric reagents, [8][9][10][11][12][13][14][15][16][17][18][19][20][21] or are used as co-catalyst. [22][23][24][25][26][27][28] The transmetalation reaction has been studied in some cases by computational methods, but experimental quantitative data are scarce.…”

“…In the last years, many examples of coupling reactions involving R-for-X Pd/Au transmetalations have been reported, in which organogold complexes participate as stoichiometric reagents, − or are used as cocatalyst. − The transmetalation reaction has been studied in some cases by computational methods, but quantitative experimental data are scarce. − In 2012, we reported a kinetic and computational study on the Rf/Cl exchange (transmetalation) between [PdRf 2 L 2 ] and [AuClL] (L = AsPh 3 ) . In that work, we proposed that [AuClL], acting as “incoming ligand”, substituted one L ligand at the palladium complex; at that step, the transition state displayed a Pd–Au interaction.…”

Copper(i) activation of C–X bonds: bimolecularvs.unimolecular reaction mechanism

“…These two fluoroaryl rings (Pf and Rf) are almost identical in terms of their reactivity, thus the reaction can be considered a quasi -self-exchange system, simplifying the kinetic treatment of data. 11…”