Synthesis and characterization of Pd(IMe)2, and its reactivity by C–S oxidative addition of DMSO

Bite-angle bending as a key for understanding group-10 metal reactivity of d10-[M(NHC)2] complexes with sterically modest NHC ligands

“…A search on all currently known X-ray crystal structures of d 10 -[M(NHC) 2 ] complexes reveal that the dihedral angles between the NHC nitrogen and NHC carbene carbon atoms increases for bulky substituents. 5a , 6 , 7 , 11 Calculations on [M(H 2 Im) 2 ] presented earlier 12 predict a D 2d type structure also for sterically less demanding NHCs. However, calculations on [M(iPr 2 Im) 2 ] (M = Ni, Pd, Pt) performed at BP86/def2-TZVPP level (see ESI † ) reveal a shallow potential for the rotation of the NHC ligands and differences in energy between a D 2d and D 2h type structure below 5 kJ mol –1 in favor of a staggered alignment.…”

“… 5 Investigations on isolated palladium(0) and especially on platinum(0) complexes bearing two NHC ligands are scarce and mainly involve NHCs with sterically demanding nitrogen substituents. 6 , 7 For palladium, two major pathways for the synthesis of complexes [M(NHC) 2 ] have been established: (i) ligand substitution at [Pd(P{ o Tol} 3 ) 2 ] ( o Tol = 2-CH 3 –C 6 H 4 ) developed by Herrmann et al 6 a and (ii) ligand substitution at dimeric [(Pd(η 3 -C 4 H 7 )Cl) 2 ] in the presence of sodium dimethylmalonate, developed by Caddick and Cloke et al 6 b The latter procedure does not require the unappealing synthesis of the [Pd(P{ o Tol} 3 ) 2 ] precursor, 8 but the stoichiometry has to be controlled carefully due to equilibration in solution, since NHC dissociation from palladium seems to be more facile than generally envisioned. 6 c However, using these methods, complexes such as [Pd(Dipp 2 Im) 2 ] (Dipp = 2,6-diisopropyl-phenyl), [Pd(Mes 2 Im) 2 ] (Mes = 2,4,6-trimethyl-phenyl), [Pd( t Bu 2 Im) 2 ], [Pd(Ad 2 Im) 2 ] (Ad = adamantyl) and of other NHCs with sterically demanding substituents at nitrogen have been prepared.…”

“…6 c However, using these methods, complexes such as [Pd(Dipp 2 Im) 2 ] (Dipp = 2,6-diisopropyl-phenyl), [Pd(Mes 2 Im) 2 ] (Mes = 2,4,6-trimethyl-phenyl), [Pd( t Bu 2 Im) 2 ], [Pd(Ad 2 Im) 2 ] (Ad = adamantyl) and of other NHCs with sterically demanding substituents at nitrogen have been prepared. 6 Furthermore, synthesis of [Pd(Me 2 Im) 2 ] via potassium reduction of [Pd(Me 2 Im) 2 Cl 2 ] and the characterization of this complex including X-ray analysis has been described lately. 6 j In course of these studies, it turned out that complexes of the type [Pd(NHC) 2 ] are extremely air sensitive and form isolable peroxo or peroxocarbonate complexes.…”

In Situ Generation of ArCu from CuF2 Makes Coupling of Bulky Aryl Silanes Feasible and Highly Efficient

“…Combustion CHN analyses were made on aP erkin-Elmer 2400 CHN microanalyzer.U nless specified otherwise, all compounds used were purchased from commercial sources and used without further purification. Compounds 3, [44] 8, [45] [PdCl 2 (IDM) 2 ], [46] [PdCl 2 (AsPh 3 )(IDM)], [16b] 4, [47] PEPPSI, [48] trans-[Pd(C 6 F 5 )(Br)(PPh 3 ) 2 ], [49] trans-[Pd(C 6 H 4 CF 3 )(I)(PPh 3 ) 2 ], [50] trans-[Pd(C 6 H 4 CF 3 )(F)(PPh 3 ) 2 ], [51] [CuF 2 (bipy)]·3H 2 O( bipy = 2,2'-bipyridine), [52] ClÀSi(OEt) 3 , [53] and 1-[2-(diphenylphosphino)phenyl]-N,N-dimethylmethanamine [54] were made by methods reported in the literature. Particularly,anhydrous CuF 2 was purchased from Alfa Aesar,P h ÀSi(OEt) 3 was purchased from Aldrich, and (C 6 F 5 )Si(OEt) 3 from Fluorochem.…”

A Highly Substitutable Palladium(II) Complex Stabilized by the Smallest Steric N‐Heterocyclic Carbene, IMe (IMe = 1,3‐Dimethylimidazole‐2‐ylidene)

“…3,11 However, most of mono-ligated NHC palladium complexes contain bulky NHCs with relatively strongly bound anions such as acetate anions, or halide-or carboxylate-bridged palladium dimers are obtained. 17,18 Here, we report the preparation and full characterization of a mono-ligated palladium(II) complex supported by IMe (IMe = 1,3-dimethylimidazole-2-ylidene), triflate, and THF. 14 Therefore, the access to a mono-ligated NHC complex with weakly coordinating ligands is very limited.…”