Cooperative activation of X–H (X = H, C, O, N) bonds by a Pt(0)/Ag(i) metal-only Lewis pair

Abstract

Metal-only Lewis pairs made of Pt(0)/Ag(i) combinations have been previously reported, but their cooperative reactivity remains unexplored.

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

“…As mentioned briefly above, water activation by combining 1 with transition metal Lewis acids [Cu(CH 3 CN) 4 ]PF 6 11 and AgNTf 2 , 12 has recently been reported. Formation of an intermediate characterized by a Pt → M dative interaction is proposed as the initial step in both cases, after which the cooperative cleavage of the O–H bond takes place.…”

“…In contrast, equimolar benzene suspensions of 1 and ZnX 2 (X = Cl, Br, I, and OTf) readily react with H 2 O (5 equiv) by means of O–H bond activation ( Scheme 3 ). 11 , 12 It is important to remark that 1 does not react with water on its own even under more forcing conditions (80 °C, 24 h). However, in the presence of zinc halides formation of trans -[PtHX(P t Bu 3 ) 2 ] (X = Cl, Br, and I; 4 , Scheme 3 ) is evidenced by a distinctive low-frequency 1 H NMR resonance due to the metal hydride (δ = −19.2 ( 4a , Cl), −18.4 ( 4b , Br), and −16.4 ( 4c , I) ppm), exhibiting scalar coupling to both 31 P ( 2 J HP ≈ 12 Hz) and 195 Pt ( 1 J HPt ≈ 1100 Hz) nuclei.…”

“… 11 Similarly, we have explored the reactivity of [(P t Bu 3 ) 2 Pt → AgNTf 2 ] (NTf 2 = bis(trifluoromethanesulfonyl)imide), which readily cleaves X–H (X = H, C, O, and N) bonds across the Pt–Ag linkage, while the parent monometallic components remain inactive. 12 On these grounds, we decided to inspect the formation and reactivity of zinc-containing MOLPs based on [Pt(P t Bu 3 ) 2 ] ( 1 ). In doing so, we have examined its reactivity with a range of zinc precursors, more precisely ZnX 2 (X = Cl, Br, I, and OTf; OTf = trifluoromethanesulfonate), ZnR 2 (R = Me, Et, Ph, η 5 -C 5 Me 5 , and C 6 F 5 ), and the more exotic Zn(I) dimer [Zn 2 (η 5 -C 5 Me 5 ) 2 ] (Zn 2 Cp* 2 ).…”

Reversible Hydride Migration from C5Me5 to RhI Revealed by a Cooperative Bimetallic Approach

“…There are, however, examples that demonstrate the potential of bimetallic entities to tackle these difficulties. [31] In the present case, we noticed that metal adducts 3 exhibit no reactivity towards the explored EÀH bonds, while compounds of type 4 were active even under very mild conditions (Scheme 3 a), particularly for N-H activation. This behaviour was especially obvious for the mixture of 3 b and 4 b, where only the Cp*-activated compound (4 b) evolved and the bimetallic adduct (3 b) remained unaltered ( Figure S2).…”

Mechanistic investigations via DFT support the cooperative heterobimetallic C–H and O–H bond activation across TaIr multiple bonds

“…This can be explained, in part, by the common use of sterically encumbering polyfunctional chelating ligands to drive the assembly of the two metals, which restrains the accessibility of both metal cores, therefore limiting their interest for catalysis. Still, rare examples of heterobimetallic oxidative additions (HBOA) of H-H, [10][11][12][13][14][15] C-X (X = halide, 16,17 H, [18][19][20][21][22] OH, [23][24][25][26] NHR, [23][24][25] ), Si-H 24 or B-H 27 bonds across metal-metal' bonds have emerged in the literature (see Figure 1). These pioneer studies highlight the potential of polarized heterobimetallic metalmetal bonds to promote the cooperative cleavage of strong sigma bonds.…”