Synthesis and catalytic activity of three-coordinate zinc cations

Abstract

Reaction between DADZnR2 and either B(C6F5)3 or ZnR2 and [DADH][B(C6F5)4] affords three-coordinate alkyl and amide zinc cations which are active for the ring opening polymerisation of epoxides and e-caprolactone [DAD = (MeC=NC6H3Pri2-2,6)2]

Synthesis and crystal structure of [C6H5Hg(H2NSiMe3)][H2N{B(C6F5)3}2], a phenyl–mercury(II) cation stabilised by a non-coordinating counter-anion

“…The new heteroleptic mercury(II) complex PhHgN-(SiMe 3 ) 2 (1) was prepared by treatment of PhHgCl with freshly prepared NaN(SiMe 3 ) 2 in toluene at room temperature (Scheme 2) and isolated as a colourless solid in high yield. Compound 1 is highly soluble in chlorinated solvents (2), and this was corroborated by elemental analysis.…”

“…In the past few years, we have been interested in the isolation of electron deficient complexes of Zn, Cd and Mg and their use as initiators for ring-opening polymerisation of polar monomers [1][2][3][4][5]. With this aim, strong Brønsted acids such as [H(OEt 2 ) 2 ][B(C 6 F 5 ) 4 ] [6] or [H(OEt 2 ) 2 ][H 2 N-{B(C 6 F 5 ) 3 } 2 ] [7] have been employed as a convenient way to generate cationic metal species by protolysis of a metal alkyl, amido or alkoxide bonds.…”

Cationic Brønsted Acids for the Preparation of SnIV Salts: Synthesis and Characterisation of [Ph3Sn(OEt2)][H2N{B(C6F5)3}2],[Sn(NMe2)3(HNMe2)2][B(C6F5)4] and [Me3Sn(HNMe2)2][B(C6F5)4]

“…[46] In addition, the anilinium salts [PhNMe 2 4 ] have long been known and used as activating agents in olefinpolymerisation catalysis. [48][49] As part of our ongoing studies on the preparation and the reactivity of main-group element cations, [43][44][45]47,50] (2) in hot toluene (Scheme 2). The 119 Sn NMR spectrum of 1 exhibited a single peak at δ -106.4 ppm, i.e.…”

“…[43][44][45][46][47] For instance, the reactions of ZnR 2 [R = C 6 [44][45] [(Et 2 O) 3 MgR][X] [45] and [Cp 2 Zr(OiPr)(HO-iPr)] [X]. [46] In addition, the anilinium salts [PhNMe 2 4 ] have long been known and used as activating agents in olefinpolymerisation catalysis.…”

Zinc: Inorganic & Coordination ChemistryBased in part on the article Zinc: Inorganic & Coordination Chemistry by Reg H. Prince which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

“…Three-coordinate zinc complexes of the extremely sterically demanding diazabutadiene ligand RN=CMe-CMe=NR with R = 2,6-i Pr 2 C 6 H 3 (the third ligand is alkyl or N(SiMe 3 ) 2 ) are catalysts for ring-opening polymerization of propene oxide and ε-caprolactone, thanks to the relatively high Lewis acidity of the zinc and its accessibility in this low-coordination number environment. 104 Both Zn 2+ ions are five coordinate in a dimeric rotaxane containing phen and terpy units in each monomeric component. Addition of an excess of Cu + to this doubly threaded molecular assembly displaces the zinc, and decreases the length of the molecule from 83 to 65Å as the threads slide along each other so that the Cu + ions are both coordinated by two phen moieties.…”