Novel highly emissive tetracyanotetraphenylporphyrazine ytterbium complex for optoelectronic and biophotonic applications

The preparation is described of a novel highly emissive ytterbium complex with a proposed unusual structure obtained by reaction of tricyanovinylbenzene (TCNVB) with bis(indenyl)ytterbium(II) in THF. The reaction occurs under extremely mild conditions, the tetraphenyltetracyanoporphyrazine macrocycle being assembled in high yield from TCNVB building-blocks by Yb 3+ -template synthesis. The analytical, spectral and electrochemical investigations of the obtained ytterbium complex indicate its existence in the form of a binuclear adduct with Yb(TCNVB)3 species in which a one doubly reduced TCNVB molecule bridges two Yb 3+ cations. The formation of a disordered polynuclear coordination polymer network including a macrocyclic structure and metal cations bridged through the nitrile nitrogen atoms is proposed. The complex is readily soluble and is compatible with a variety of polymeric matrices giving doped polymeric glasses and films which are highly luminescent in the biologically relevant optical window covering the visible and near infrared range (640-1000 nm). In addition, doped polymeric glasses and films highly emissive at the telecommunication wavelength (1540 nm) including the novel ytterbium complex and originally not luminescent erbium chelate in an equimolar ratio have been obtained. The compound is found to be an extraordinarily strong sensitizer of near-IR Er 3+ emission. Use of the Yb complex as a fluorescent marker for biomedical in vitro investigations has been demonstrated.