Self‐Assembled, Highly Positively Charged, Allyl–Pd Crowns: Cavity‐Pocket‐Driven Interactions of Fluoroanions. Issue 35 (3rd June 2020)

• Record Type: Journal Article
• Authors: Ferrer, Montserrat; Gallen, Albert; Gutiérrez, Albert; Martínez, Manuel; Ruiz, Eliseo; Lorenz, Yvonne; Engeser, Marianne
• Is Part Of: Chemistry. Volume 26:Issue 35(2020)
• Page Start: 7847
• Page End: 7860
• Publication Date: 2020-06-03
• Subjects: allyl compounds -- fluoroanions -- metallacycles -- noncovalent interactions -- self-assembly; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202000316
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A series of dodecanuclear highly positively charged homo‐ and heterometallamacrocycles [{Pd(η 3 ‐2‐Me‐C3 H4 )}6 (4‐PPh2 py)12 {M2 (tpbz)}3 ] 18+ (M=Pd, Pt; tpbz=1, 2, 4, 5‐tetrakis(diphenylphosphanyl)benzene were synthesized by the quantitative self‐assembly of {Pd(η 3 ‐2‐Me‐C3 H4 )} +, {M2 (tpbz)} 4+ and 4‐PPh2 py moieties in 2:1:4 molar ratio. The cationic assemblies were obtained as salts of different fluorinated anions with diverse sizes and electronic properties, namely BF4 −, PF6 −, SbF6 − and CF3 SO3 − . The new crown‐like metallamacrocycles showed remarkable differences in their NMR spectra due to the presence of the different counteranions. On the basis of the observed variations, the metallacycles have been tested as catalytic precursors in allylic alkylation reactions. The anion‐dependent activity and selectivity has been analysed and compared with that of the corresponding monometallic allylic corners [Pd(η 3 ‐2‐Me‐C3 H4 )(4‐PPh2 py)2 ]X (X=BF4 −, PF6 −, SbF6 −, CF3 SO3 − ). DFT calculations have been employed in order to help to the interpretation of the experimental data and to model the anion–crown interactions. Abstract : King‐size positively charged void : Selective self‐assembly of crown‐like, highly positively charged, homo and heterometallamacrocycles is described. These high nuclearity systems were obtained as ionic salts of different fluorinated anions of different sizes and electronic properties. DFT calculations indicate the existence of six relevant positive pockets inside the cavity, which could accommodate the same number of fluoroanions. The catalytic activity of the assemblies in the allylic alkylation reaction has been investigated.