Structural investigations on new iron-acyl derivatives of B(C6F5)3

Lewis Acid Effects on Calculated Ligand Electronic Parameters

“…To address the organometallic functionalization of carbonyl-derived ligands (acetyl, formyl, benzoyl), which can result from the LA-assisted migration of nucleophiles, ,− we elected to model the acetyl group. Lewis acid interactions with the acetyl group were found to have a significant effect on donor strength (Δν CO = −30 – −41 cm –1 ; Table S39) with moderate dependence on Lewis acidity (ΔΔν CO = 11 cm –1 ).…”

“…An important strategy for designing LA-assisted reactions is to impart stabilization of either high-energy transition states or intermediates in preference to the ground-state starting materials or byproducts . Within this approach, modeling interactions between CO, a common precursor to acetyl or acyl intermediates, ,− and the Lewis acid, BF 3 , were unsuccessful, consistent with prior reports. Thus, simple computational models for parametrization could enable the development of strategies to direct reactivity by stabilizing specific intermediates/transition states.…”

“…Lewis acid interactions with the acetyl group were found to have a significant effect on donor strength (Δν CO = −30 − −41 cm −1 ; Table S39) with moderate dependence on Lewis acidity (ΔΔν CO = 11 cm −1 ). Consistent with prior reports, 73,76 Lewis acid interactions with the acetyl group weaken the CO double bond (bond index = 1.75−1.40), while having a negligible impact on the Ni−C bond (bond index = 0.71− 0.78). Importantly, when the Lewis acid (BF 3 ) interacts with the acetyl group, the energy of the acetyl CO π* orbital is lowered by 0.91 eV (Figure 7).…”

B(C6F5)3 adducts of transition metal acyl compounds

“…1 We have recently shown that compounds of the general formula [Fe(g 5 -C 5 H 5 )(L)(CO)(COMe)] (L = CO or tertiary phosphine), form adducts of the type [Fe(g 5 -C 5 H 5 )(CO)(L)(C{OB(C 6 F 5 ) 3 }Me)] (L = CO or tertiary phosphine), in which B(C 6 F 5 ) 3 is bound exclusively to the acyl oxygen atom. 2 Here we describe the synthesis of a series of B(C 6 F 5 ) 3 -bound transition metal acyl compounds, showing that this mode of reactivity is general.…”

“…The reaction of B(C 6 F 5 ) with water has been well documented, 14 and the presence of adventitious water has given rise to some unusual complexes. 2 During the attempted crystal growth of the compound 5, crystals of [Co{HOB(C 6 F 5 ) 3 } 2 {OP(4-F-C 6 H 4 ) 3 } 2 ] that were suitable for structural characterisation were formed. The molecular structure of compound 9 is shown in Fig.…”