Two types of immobilized on the amino-functionalized polystyrene-supported acyclic diaminocarbene palladium complexes (ADC-Pd^II) are investigated under Sonogashira cross-coupling conditions. Depending on substituents in the diaminocarbene fragment immobilized ADC-Pd^II, systems are found to have different catalytic activity and stability regarding Pd-leaching. Pd^II-diaminocarbenes possessing protons at both nitrogen atoms smoothly decompose into Pd⁰-containing species providing a catalytic “cocktail system” with high activity and ability to reuse within nine runs. Polymer-supported palladium (II) complex bearing NBn–C_carbene–NH-moiety exhibits greater stability while noticeably lower activity under Sonogashira cross-coupling. Four molecular ADC-Pd^II complexes are also synthesized and investigated with the aim of confirming proposed base-promoted pathway of ADC-Pd^II conversion through carbodiimide into an active Pd⁰ forms.

A new convenient approach to the synthesis of useful N-heterocyclic carbene complexes of group 13 metals was successfully developed. We demonstrate that air-stable copper(I) diaminocarbene complexes are excellent carbene transfer reagents for the synthesis of (IMes or IPr)MCl₃ with high yields (M = Al, Ga). Use of this simple method allowed for the first time to obtain (IPr)AlCl₃, inaccessible via a free carbene route. In contrast to copper complexes, under the same conditions the more commonly used silver analog (IPr)AgCl reacts with MCl₃ (M = Al, Ga, In) yielding only the homoleptic cationic complexes [(IPr)₂Ag]⁺MCl₄ ⁻.

The carbene transfer from N-heterocyclic carbene complexes of Group 11 metals (NHC–M^C) (especially silver and copper) to other metals is considered a convenient and universal, sometimes having no alternative, method for the synthesis of a wide range of important N-heterocyclic carbene complexes of transition metals. As the number of successful examples of transmetalation with the formation of the target product has increased, the data were accumulated on alternative or unexpected results of the interaction of NHC–M^C complexes with compounds of other metals. This review considers the examples of NHC–M^C reactions with compounds of other metals which proceed with a change in the metals oxidation state, conversion of (NHC)M^CX into cationic homoleptic [(NHC)₂M^C]⁺ forms, transmetalation retaining the other metal in the coordination sphere of the product, or formation of heterometallic adducts preserving the M^C–C_carbene bond, rather than these occurring according to the standard reaction pathway. Unusual “reverse” carbene transfer reactions have been considered separately. The review material reveals a promising new synthetic potential of NHC–M^C in the reactions with other metals and discusses the possible mechanisms and driving forces of such transformations. The most important aspects of the application of the obtained products, primarily in various catalytic processes, have been considered as well.