Group 11 Borataalkene Complexes: Models for Alkene Activation

Abstract

A series of linear late transition metal (M=Cu, Ag, Au and Zn) complexes featuring a side‐on [B=C]− containing ligand have been isolated and characterised. The [B=C]− moiety is isoelectronic with the C=C system of an alkene. Comparison across the series shows that in the solid‐state, deviation between the η2 and η1 coordination mode occurs. A related zinc complex containing two [B=C]− ligands was prepared as a further point of comparison for the η1 coordination mode. The bonding in these new complexes has been interrogated by computational techniques (QTAIM, NBO, ETS‐NOCV) and rationalised in terms of the Dewar–Chatt–Duncanson model. The combined structural and computational data provide unique insight into catalytically relevant linear d10 complexes of Cu, Ag and Au. Slippage is proposed to play a key role in catalytic reactions of alkenes through disruption and polarisation of the π‐system. Through the preparation and analysis of a consistent series of group 11 complexes, we show that variation of the metal can impact the coordination mode and hence substrate activation.

A Boratafulvene

“…[23] Respectively, (N‐heterocyclic) borataalkenes were most recently shown to be suitable ligands. [ 12b , 24 ]…”

Group 11 Borataalkene Complexes: Models for Alkene Activation

“…[57] But in this case the borataalkene coordinates as the h 1 -C and not h 1 -B isomer with the MÀC interaction dominating the bonding interaction, this differ- 1) 97.3. [74] Angewandte Chemie Forschungsartikel 12122 www.angewandte.de ence is likely an effect of the very different steric profiles around the Band Ca toms in A and [CH 2 = B(C 6 F 5 ) 2 ].…”

“…Figure 3. a) X-ray diffraction determined structures for 3a-c.Key structural parameters (distances in ,angles in 8 8): 3a-Cu(1)-C(1) 1.944(2), Cu(1)-B(31)2 .121(2), Cu(1)-C(32) 2.411(2), B(31)-C(32)1 .469(3), N(33)-C(32) 1.406(6);C (1)-Cu(1)-B(31) 156.39(8), Cu(1)-B(31)-C(32) 82.2(1), S angles N(33) 360(2); 3b-Ag(1A)-C(1A) 2.151(4), Ag(1A)-B(31A)2 .287(3), Ag(1A)-C(32A) 2.633(3), B(31A)-C(32A) 1.473(5), N(33A)-C(32A) 1.413(5);C (1A)-Ag(1A)-B(31A) 158.5(1), Ag(1A)-B(31A)-C(32A) 86.0(2), S angles N(33A) 360(1); 3c-Au(1A)-C(1A) 2.088(9), Au(1A)-B(31A) 2.23(1), Au(1A)-C(32A) 2.68(1), B(31A)-C(32A) 1.52(2), N(33A)-C(32A) 1.39(1);C(1A)-Au(1A)-B(31A) 160.1(4), Au(1A)-B(31A)-C(32A) 89.0(7), S angles N(33A) 363(3). b) Measuring the displacement (d) of the coinage metal centre along the BÀCbond (r) [74]. …”

“…Figure 4. X-ray diffraction determined structures for 4.K ey structural parameters (distances in ,angles in 8 8): Zn-B(1) 2.139(2), B(1)-C(2) 1.505(2);B (1)-Zn(1)-B(1A) 164.5(1), Zn(1)-B(1)-C(1) 97.3 [74]. …”

Ein Boratafulven

“…Diese haben sich als vielfältige C‐nukleophile Liganden in der Koordinationschemie erwiesen [23] . Auch (N‐heterozyklische) Borataalkene konnten kürzlich als geeignete Liganden Anwendung finden [12b, 24] …”