Metal-only Lewis pairs featuring unsupported Pt→M (M = Zn or Cd) dative bonds

Abstract

Reactions of [Pt(PCy(3))(2)] (Cy = cyclohexyl) with group 12 metal dihalides have afforded the novel metal only Lewis pair (MOLP) complexes, [(Cy(3)P)(2)Pt→MX(2)] (M = Zn or Cd, X = Br or I), or the oxidative addition product, trans-[(Cy(3)P)(2)(I)PtHgI]. The zinc complex represents the first MOLP to contain an unsupported Pt→Zn linkage.

Activation of Homolytic SiZn and SiHg Bond Cleavage, Mediated by a Pt0 Complex, via Novel PtZn and PtHg Compounds

“…[2][3][4] Several methodologies are available for their synthesis.O ne involves the formation of PtÀZn heteronuclear dative linkages from Lewis basic and Lewis acidic metals (termed metal-only Lewis pairs (MOLPs)). [2] Fischer et al reported an umber of novel {PtÀZnCp*} (Cp* = pentamethylcyclopentadienyl) complexes in which ad ivalent zinc is bonded directly to platinum. [2] Fischer et al reported an umber of novel {PtÀZnCp*} (Cp* = pentamethylcyclopentadienyl) complexes in which ad ivalent zinc is bonded directly to platinum.…”

“…[3] Complexes in which Pt and Zn are bridged by ligands were also isolated and characterized. (2)]. (1)].T hese novel hexacoordinate PtÀMSiR 3 compounds were isolated and characterized by Xray crystallography and their photolysis and thermolysis is reported.…”

“…[5] For example,upon day-light exposure for 30 min [(tBuMe 2 Si) 2 Zn] (7)o r[ ( tBuMe 2 Si) 2 Hg] (8)u ndergo quantitative demetallation forming short-lived [tBuMe 2 Si]C radicals which dimerize to disilane 9 (95 %) or abstract an hydrogen (5 %) to form silane 10 [Eq. [5] For example,upon day-light exposure for 30 min [(tBuMe 2 Si) 2 Zn] (7)o r[ ( tBuMe 2 Si) 2 Hg] (8)u ndergo quantitative demetallation forming short-lived [tBuMe 2 Si]C radicals which dimerize to disilane 9 (95 %) or abstract an hydrogen (5 %) to form silane 10 [Eq.…”

“…[2][3][4] Several methodologies are available for their synthesis.O ne involves the formation of PtÀZn heteronuclear dative linkages from Lewis basic and Lewis acidic metals (termed metal-only Lewis pairs (MOLPs)). The reaction proceeds via hexacoordinate Pt complexes,( M= Zn (2a and 2b), M = Hg (3a and 3b)) which were isolated and characterized.…”

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The thermally stable [(tBuMe 2 Si) 2 M] (M = Zn, Hg) generate R 3 SiC radicals in the presence of [(dmpe)Pt(PEt 3 ) 2 ]at 60-80 8 8C. [2] Fischer et al reported an umber of novel {PtÀZnCp*} (Cp* = pentamethylcyclopentadienyl) complexes in which ad ivalent zinc is bonded directly to platinum. Mild warming or photolysis of 2 or 3 lead to homolytic dissociation of the PtÀMSiR 3 bond generating silyl radicals and novel unstable pentacoordinate platinum paramagnetic complexes (M = Zn (5), Hg (6)) whose structures were determined by EPR spectroscopya nd DFT calculations.

The vigorously developing chemistry of heterometallic complexes containing two or more different metals is of considerable contemporary interest with avariety of applications in synthesis,c atalysis,a nd materials chemistry.

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