A ruthenium(II) allenylidene complex with a 4,5-diazafluorene functional group: A new building-block for organometallic molecular assemblies

The synthesis of the new ruthenium(II) allenylidene complex [ClRu(dppe)2double bond; length as m-dashCdouble bond; length as m-dashCdouble bond; length as m-dashC11H6N2][OTf] (4) (dppe = 1,2-bis(diphenylphosphino)ethane) terminated with a 4,5-diazafluorene ligand is reported. Further coordination of that metal allenylidene to ruthenium and rhenium moieties leads to the bimetallic adducts [ClRu(dppe)2double bond; length as m-dashCdouble bond; length as m-dashCdouble bond; length as m-dashC11H6N2{Ru(bpy)2}][B(C6F5)4]3 (5a), [ClRu(dppe)2double bond; length as m-dashCdouble bond; length as m-dashCdouble bond; length as m-dashC11H6N2{Ru(tBu-bpy)2}][PF6]3 (5b) and [ClRu(dppe)2double bond; length as m-dashCdouble bond; length as m-dashCdouble bond; length as m-dashC11H6N2{Re(CO)3Cl}][OTf] (6). Their optical and electrochemical properties show that the allenylidene moiety is an attractive molecular clip for the access to larger original redox-active homo/heteronuclear multi-component supramolecular assemblies. The X-ray crystal structure of the allenylidene metal building block is also described.