Dinuclear Complexes of the N₂O₂ Oxime Chelate Ligand with Zinc(II)–Lanthanide(III) as a Selective Sensitization System for Sm³⁺

Abstract

Abstract A series of zinc(II)–lanthanide(III) dimetallic complexes have been synthesized by the one‐pot reaction of the oxime‐based N 2 O 2 chelate ligand H 2 L with zinc(II) acetate and lanthanide(III) salts. The heavier lanthanides (Sm–Lu) producedheterodinuclear complexes [LZnLn] 3+ (Ln = Sm–Lu) in which the zinc(II) ion occupies the N 2 O 2 chelate site of H 2 L and the lanthanide(III) ion is located in the semicircular O 4 site. In contrast, the trinuclear complex [(LZn) 2 La] 3+ was obtained by the reaction of H 2 L with zinc(II) and lanthanum(III) salts. The heterometallic complexes [LZnLn] 3+ and [(LZn) 2 La] 3+ were also formed by the reaction of [L 2 Zn 3 ] 2+ with the heavier lanthanides (Sm 3+ –Lu 3+ ) and La 3+ , respectively. The dinuclear complex [LZnSm(OAc) 3 ] exhibited a relatively intense red emission due to Sm 3+ , whereas [LZnEu(OAc) 3 ] gave no detectable emission. The corresponding complexes containing other lanthanides showed only a weak blue emission due to the ligand moiety. Therefore the ligand L 2– can selectively sensitize Sm 3+ from among Sm 3+ , Eu 3+ , Tb 3+ , and Dy 3+ , although these complexes would often exhibit f–f luminescence. The deep‐red luminescence from samarium(III) at around 650 nm is potentially useful for a full‐color display. In addition, [LZnYb(OAc) 3 ] exhibited near‐infrared luminescence.