Influence of the steric properties of pyridine ligands on the structure of complexes containing the {LnCd2(bzo)7} fragment.

The reaction of Cd(NO₃)₂ · 4H₂O and Eu(NO₃)₃ · 6H₂O or Tb(NO₃)₃ · 6H₂O with potassium 3,5-di-tert-butylbenzoate (Kbzo) and N-donor ligands (1,10-phenanthroline (phen), 2,4-lutidine (2,4-lut), 3,4-lutidine (3,4-lut), phenanthridine (phtd), 2,3-cyclododecenopyridine (cdpy), acridine (acr)) afforded heterometallic LnCd₂ complexes: [EuCd₂(bzo)₇(EtOH)₂(phen)] (2), [LnCd₂(bzo)₇(2,4-lut)₄] (Ln = Eu (3), Tb (4)), [EuCd₂(bzo)₇(H₂O)₂(2,4-lut)₂] · MeCN (5), [EuCd₂(NO₃)(bzo)₆(EtOH)₂(2,4-lut)₂] (6), [EuCd₂(bzo)₇(H₂O)(EtOH)(3,4-lut)₂] · 5EtOH (7), 3[EuCd₂(bzo)₇(H₂O)₂(phtd)₂] · 4phtd (8), [EuCd₂(bzo)₇(EtOH)₃(cdpy)] (9), 2[EuCd₂-(bzo)₂(EtOH)₄] · acr (10). The structures of complexes 2, 3, and 5–10 were determined by single-crystal X-ray diffraction. The isostructurality of complexes 3 and 4 was confirmed by powder X-ray diffraction. The structure of the trinuclear {Ln₂Cd} metal core is stable and independent of the type of peripheral ligands coordinated to cadmium atoms. Photoluminescent properties of compounds 3 and 4 were studied. [ABSTRACT FROM AUTHOR]