Dynamic, Reversible Oxidative Addition of Highly Polar Bonds to a Transition Metal

Abstract

ABSTRACT:The combination of Pt 0 complexes and indium trihalides leads to compounds that form equilibria in solution between their In-X oxidative addition (OA) products (Pt II indyl complexes) and their metal-only Lewis pair (MOLP) isomers (L n Pt→InX 3 ). The position of the equilibria can be altered reversibly by changing the solvent, while the equilibria can be reversibly and irreversibly driven towards the MOLP products by addition of further donor ligands. The results mark the first observation of an equilibrium between MOLP and OA isomers, as well as the most polar bond ever observed to undergo reversible oxidative addition to a metal complex. In addition, we present the first structural characterization of MOLP and oxidative addition isomers of the same compound. The relative energies of the MOLP and OA isomers were calculated by DFT methods, and the possibility of solvent-mediated isomerization is discussed.

Reactivity of [Pt(PtBu3)2] with Zinc(I/II) Compounds: Bimetallic Adducts, Zn–Zn Bond Cleavage, and Cooperative Reactivity

“…The most distinctive feature is a pronounced decrease in the 1 J PPt coupling constant to a value of 3328 Hz (δ = 93.1 ppm; c.f. 1 : δ = 100.2 ppm, 1 J PPt = 4410 Hz), a common symptom of MOLP formation in Pt(0) compounds due to the reduced s character of the Pt–P bonds in the bimetallic adduct. , Alongside this, a new set of 19 F­{ 1 H} resonances at −115.7, −157.4, and −162.0 ppm (c.f. Zn­(C 6 F 5 ) 2 : δ = −118.0, −152.5, and −160.5 ppm) was recorded.…”

“…As for Lewis basic fragments, [Pt­(PCy 3 ) 2 ] (Cy = cyclohexyl) is likely the most extensively investigated donor in MOLP chemistry . In fact, recently reported [(PCy 3 ) 2 Pt → ZnBr 2 ] is the first well-defined unsupported M → Zn­(II) adduct .…”

Low-oxidation state cobalt–magnesium complexes: ion-pairing and reactivity

“…To our knowledge, this is the first clear example of reversible ion-pairing in a molecular transition metal-magnesium complex. 14 When a stronger ligand is added, such as DMAP, the solvent separated species ( 2·DMAP ) is observed even in non-donor solvents, indicating that metal–metal bond formation does not occur in this case (see the ESI † for further details, DMAP = dimethylaminopyridine). It should be noted that the ionic form has little effect on the UV-Vis spectra of 2 / 2·THF , both having similar absorption maxima at 351 and 347 nm, respectively (see ESI † ).…”

“…The 31 P{ 1 H} NMR spectrum shows a singlet at δ = 3.2 ppm (see ESI † ), which is reminiscent of the potassium analogue (2.4 ppm). 14 It was not possible to crystallographically characterise the solvent separated ion-pair, as it precipitates out of solution as a powder due to its low solubility in THF. Attempts to recrystallise it from toluene instead formed the coordination compound ( Dep nacnac)Mg(THF)Co(P 2 C 2 t Bu 2 ) 2 ( 5 , see ESI † ).…”

Theoretical Study on Si−Cl Bond Activation in Pd‐Catalyzed Cross‐Coupling of Chlorosilanes with Organoaluminum

“…In the trans-oxidative addition pathway, the apical SiÀ Cl bond in the σ-acceptor (Z-type) chloro-silane ligand is eliminated to directly afford the trans-chloro-silyl complex (Figure 1a). This peculiar oxidative addition has been proposed for polar and strong BÀ X (X=F [16] and Br [17] ), PÀ F, [18] and InÀ X (X=Cl, Br, and I) [19] bond activation using 14-electron Pt{P(t-Bu 3 )} 2 complex. In addition, S N 2-type [12c] and concerted cisoxidative addition [12b] have been proposed in earlier theoretical studies for SiÀ Cl bonds (Figure 1b and 1c).…”