Synthesis, Reactivity, and Lewis Acidity of Cationic Zinc Complexes

Abstract

Reactions of Rnac2ZnEt (R = Mes, Dipp) and 16Fnac2ZnEt with [Ph3C]­[B­(C6F5)4] simultaneously proceed with β-hydride elimination and ethyl abstraction and formation of the corresponding zinc cations [Rnac2Zn]+ and [16Fnac2Zn]+. While [Rnac2Zn]+ cations undergo additional side reactions but do not react with the [B­(C6F5)4]− anion, [16Fnac2Zn]+ activates the borate anion with formation of 16Fnac2ZnC6F5 (1). In contrast, [16Fnac2Zn]­[SbF6] (2) was formed in the reaction of 16Fnac2ZnEt with [Ph3C]­[SbF6] in SO2. 2 reacts with OPEt3 with formation of [16Fnac2Zn­(OPEt3)]­[SbF6]2 (3) and with B­(C6F5)3 with formation of 1. [16Fnac2Zn]­[SbF6] is slightly less Lewis acidic in comparison to B­(C6F5)3 according to the Gutmann–Beckett method.

Understanding and Expanding Zinc Cation/Amine Frustrated Lewis Pair Catalyzed C–H Borylation

“…However, the 1 H NMR spectrum at short reaction times showed multiple NacNac species and no pure material could be isolated from this mixture. This is fully analogous to the work of Schulz and co-workers who performed the same reaction, albeit in CH 2 Cl 2 . On standing at room temperature in chlorobenzene this mixture undergoes anion decomposition ultimately leading to the formation of B­(C 6 F 5 ) 3 and (NacNac)­Zn­(C 6 F 5 ) as the major products (after 18 h by 19 F NMR spectroscopy, Figure S38).…”

“…This is fully analogous to the work of Schulz and co-workers who performed the same reaction, albeit in CH 2 Cl 2 . 21 On standing at room temperature in chlorobenzene this mixture undergoes anion decomposition ultimately leading to the formation of B(C 6 F 5 ) 3 and (NacNac)Zn(C 6 F 5 ) as the major products (after 18 h by 19 F NMR spectroscopy, Figure S38). The decomposition of the [B(C 6 F 5 ) 4 ] − anion is consistent with the considerable electrophilicity expected for the putative [(NacNac)Zn] + species.…”

Synthesis of Homo‐ and Heteroleptic Al, Ga and Zn Complexes Containing (Per)fluorinated β‐Diketiminate Ligands

“…As was observed in the zinc complexes, the Al-N bond length also increases and the N-Al-N bond angles decrease with decreasing σ-donor capacity of the β-diketiminate substituent [Mesnac 2 AlMe 2 1.916(3)/1.926(3), 95.24(12)°; [24] 10 Fnac 2 AlMe 2 1.917(2)/1.926(2), 94.00(8)°; [23] 16 Fnac 2 AlMe 2 1.948(2)/1.942(2), 93.02(7)°; [19a] and 17 Comparable trends were observed when comparing complex 16 Fnac 2 GaMe 2 (3) with Ar *nac 2 GaMe 2 ( Ar *nac 2 = HC[C(Me) N-2,6-Me 2 -C 6 H 3 ) [25] and 10 Fnac 2 GaMe 2 . [23] The most electron rich complex Ar *nac 2 GaMe 2 shows the shortest N-Ga bonds [1.988(2)/1.999( 2 [26] and (Mesnac 2 ) 2 Zn [Zn-N1 2.017(2) Å, Zn-N2 2.039(2) Å]. [27] The same is true for the N-Zn-N bond angles [( 17 We finally tested the homoleptic zinc complex 4 in transmetalation reaction with GaCl 3 .…”