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The reactions of (di-tert-butylphosphanyl)amines and P,P-di-tert-butylphosphinoselenoic amides with Alder's dimer were studied. For di-tert-butylphosphanylamines, the reaction proceeds by primary electrophilic attack of Alder's dimer at the phosphorus atom to afford a dicationic salt 3. The deprotonation of 3 led to N-phosphanylformamidine 5 (“phosfam”). Alkyl(di-tert-butylphosphanyl)amines reacted with Alder's dimer in a 2:1 molar ratio to give N-phosphanylformamidinium salts; the second equivalent of (alkylamino)phosphane acts as a base. (Arylamino)phosphanes reacted with Alder's dimer to give benzazaphospholium derivatives. To direct the electrophilic attack of Alder's dimer at the nitrogen atom, phosphinoselenoic amides were used. They reacted with Alder's dimer at the selenium atom followed by a selenium–phosphorus shift to give N-(di-tert-butylphosphoroselenoyl)formamidinium salts. The phosphinoselenoic amides with bulky substituents (adamantyl, tBu) underwent cleavage of the N–alkyl bond to afford phosfams. Various key intermediates such as 3 and 22b were isolated and characterized. A convenient method for the synthesis of carbene precursor PIII and PV N-substituted formamidinium salts was developed.

Neutral dinuclear gold(I) complexes having general formula [Au2Cl2(NHCP)] (NHCP = N-phosphanyl N-heterocyclic carbene) have been synthesized by two different synthetic procedures: i) transmetalation of the NHCP ligand from the corresponding dinuclear silver(I) complex; ii) deprotonation of the corresponding N-phosphanyl azolium/tetrahydropyrimidinium salt in the presence of the gold(I) precursor. Interestingly, although the silver complexes are invariably dinuclear dicationic species of formula [Ag2(NHCP)2](OTf)2, both stoichiometries [Au2(NHCP)2](OTf)2 and [Au2Cl2(NHCP)] are potentially accessible with gold. Preference for either stoichiometry is dictated by the steric properties of the NHCP ligand as well as by a proper choice of the experimental conditions. On the other hand, preparation of copper(I) compounds with [Cu2Cl2(NHCP)] stoichiometry leads to product mixtures and has not led up to now to pure neutral compounds. Both the silver(I) and gold(I) complexes have been structurally characterized.

Synthetic routes to novel N-phosphorylated 1,2,4-triazolium salts have been developed. Treatment of the specified salts with strong base produces new stable N-phosphorylated 1,2,4-triazol-5-ylidenes, which add Se in two stages (first at the carbene carbon and then at phosphorus) and rearrange to C-phosphorylated triazoles with heating. The capacity of such N-phosphorylated triazol-5-ylidenes to act as bidentate ligands toward transition-metal centers has also been demonstrated; in particular, the formation of two dinuclear silver carbene complexes is described herein. The structures of one representative carbene and of one carbene complex were determined by an X-ray study.

A direct synthetic approach to C-phosphanyl-N,N-dialkyl-N′-aryl(alkyl)-formamidines was developed. It was shown that phosphorylation of the formamidines proceeds at the nitrogen atom affording N-phosphanylformamidinium salts. Upon deprotonation, these salts gave C-phosphanylformamidines via formation of carbenes followed by a 1,2-phosphorus shift.

A direct synthetic approach to C-phosphanyl-N,N-dialkyl-N′-aryl(alkyl)-formamidines was developed. It was shown that phosphorylation of the formamidines proceeds at the nitrogen atom affording N-phosphanylformamidinium salts. Upon deprotonation, these salts gave C-phosphanylformamidines via formation of carbenes followed by a 1,2-phosphorus shift.

N-phosphorylated, N-heterocyclic carbenes (NHC) based on the imidazoline skeleton have been prepared for the first time. The free carbenes feature good stability and in best cases they can be stored in the solid state for months at ambient temperature without decomposition. The carbenes are capable of acting as ligands towards late transition metal centres such as silver(I). The resulting complexes are stable and can be employed as reagents for the preparation of complexes of other group 11 metals upon transmetallation. The complexes, one carbene ligand and related compounds have all been structurally characterized.