Cooperative Processes Governing Formation of Small Pentanuclear Lanthanide(III) Nanoclusters and Energy Transport within and between Them

Syntheses, lanthanide quantitative analyses, mass spectrometry and luminescence spectroscopy, and decay dynamics of crystals containing pentanuclear hetero-lanthanide(III) nanoclusters [(Ln‘5-xLnx)(NO3)6(μ5-OH)(μ4-L)2] (0 ≤ x ≤ 5), Ln‘ = Eu or Tb; Ln = La−Nd, Sm−Ho (hereafter Ln‘5-xLnx) were undertaken in search of information on factors governing self-assembly processes by which the clusters are formed and electronic interactions within and between them. The data obtained are consistent with the self-assembly of Ln‘5-xLnx nanoclusters being a concerted process featuring a profound expression of complementarity among mutually bridging [Ln(μ4-L]- and [Ln(NO3)2]+ components. The energy transport regime in crystals of Eu5-xLnx is in the dynamic regime when x = 0 or Ln = La and, at 293 K, Ln = Dy, despite the presence of two crystallographically different Eu3+ coordination environments which give rise to a doublet in the excitation and emission spectra of Eu3+(5D0). The luminescence decay behavior of Eu3+(5D0...