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

A series of zinc(II)–lanthanide(III) dimetallic complexes have been synthesized by the one‐pot reaction of the oxime‐based N2O2 chelate ligand H2L 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 N2O2 chelate site of H2L and the lanthanide(III) ion is located in the semicircular O4 site. In contrast, the trinuclear complex [(LZn)2La]3+ was obtained by the reaction of H2L with zinc(II) and lanthanum(III) salts. The heterometallic complexes [LZnLn]3+ and [(LZn)2La]3+ were also formed by the reaction of [L2Zn3]2+ with the heavier lanthanides (Sm3+–Lu3+) and La3+, respectively. The dinuclear complex [LZnSm(OAc)3] exhibited a relatively intense red emission due to Sm3+, 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 L2– can selectively sensitize Sm3+ from among Sm3+, Eu3+, Tb3+, and Dy3+, 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.