Controlled aggregation of a 1,3-diphosphacyclobutadiene complex in the coordination sphere of Ag(I) and Au(I) ions

The reaction of the 1,3-diphosphete complex [Cp'''Co(η 4 -P 2 C 2 t Bu 2 )] with the Ag(I) and Au(I) salts of the weakly coordinating anion Al{OC(CF 3 ) 3 } 4 results in aggregation processes which can be controlled by the reaction conditions. Accordingly, a variety of mono-, di- and polycationic species could be selectively isolated and characterized. Reactions of the 1,3-diphosphete complex [Cp'''Co(η 4 -P 2 C 2 tBu 2 )] (Cp''' = Cp(tBu) 3 , 1 ) with Ag[Al{OC(CF 3 ) 3 } 4 ] (Ag[TEF]) and [LAu][TEF] (L = (THT) 2 , (THT)PPh 3 ) were studied under various reaction conditions. Depending on the stoichiometry of the reactants, reaction time and temperature involved, a selective formation of the monomers, [{(Et 2 O)Ag}{Cp'''Co(µ,η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )}][TEF] ( 4 ) and [Au{Cp'''Co(η 4 :η 1 -P 2 C 2 tBu 2 )} 2 ][TEF] ( 6 ), the dimer [{(Et 2 O)Ag} 2 {Cp'''Co(µ,η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )}]·2[TEF] ( 3 ), the trimers [Au 3 {Cp'''Co(η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )} 4 ]·3[TEF] ( 7 ) and [(η 1 -PPh 3 ) 2 Au 3 {Cp'''Co(η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )} 2 ]·3[TEF] ( 8 ), and the one-dimensional polymer [Ag{Cp'''Co(η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )}] n [TEF] n ( 2 ) was realized. DFT calculations provided additional insight into the formation of the polymeric species during the assembling process of 2 , 3 and 4 . All compounds were characterized in the solid state by X-ray crystallography and in solution by multinuclear NMR spectroscopy and mass spectrometry.