One convenient Cd II -mediated C−C/C−N bond-forming strategy toward asymmetric tetra-(2-pyridine)substituted imidazolidine (L 1 ), the basic framework of several natural products with bioactivity, has been found for the first time. In the reaction of tridentate N3-set neutral pyridine-type Schiff base ligand (L) possessing a [−HCNCH 2 −] linkage with CdCl 2 at 70 °C for 3 days, one two-dimensional 4 4 topological layer [Cd 3 L 1 Cl 6 ] n (1) could be obtained, in which ligand L 1 resulted from [3 + 2] C−C/C−N asymmetric coupling dimerization of L. When equimolar amounts of NaSCN and NaNO 3 were added to the reaction mixtures, one-dimensional chain [Cd 2 L 1 (SCN)Cl 3 ] n (2) and zero-dimensional dinuclear Cd 2 L 1 (NO 3 ) 4 (MeOH) ( 3) containing the same ligand L 1 were also generated under the same reaction conditions, respectively. Obviously, the medium of the Cd 2+ ion plays the key role in solvothermal in situ formation of ligand L 1 . Moreover, new ligand tetra-substituted imidazolidine (L 1 ) could be obtained effectually from all three complexes 1−3 through the reactions of those compounds with Na 2 S.

An efficient method for the synthesis of a wide variety of N-rich heterocycles has been systematically explored. The synthetic protocol involves a solvothermal in situ metal-ligand reaction of pyridine-type Schiff base N-(2-pyridylmethyl)-pyridine-2-carbaldimine (L) with Cd 2+ ions, resulting in the efficient formation of nine temperature-dependent Cd II -complexes 1-9 supported by six types of N-rich heterocycles L 1-6 . To the best of our knowledge, both the synthetic strategy with solvothermal in situ Cd II -mediated Schiff base-conversion and N-rich heterocycle rings L 1-2 as well as cis-L 6 are reported for the first time. Meanwhile, plausible in situ formation mechanisms of L 1-6 are also proposed.

Four anion-dependent 0D Zn(II)-Yb(III) heterometallic Schiff base complexes, [YbZn2L2(OAc)4]·ClO4 (2), YbZnL2(NO3)3 (3), [(YbL)2(H2O)Cl(OAc)]2·[ZnCl4]2 (4), and YbZnL(OAc)4 (5), were assembled through central metal substitution or reconstruction from homotrinuclear Zn(II) complex {[(Zn(OAc)(H2O)L]2Zn}(ClO4)2·4H2O [1; HL = 2-ethoxy-6-[(pyridin-2-ylmethylimino)methyl]phenol] with different Yb(III)X3 salts [X = ClO4 (2), NO3 (3), Cl (4), and OAc (5)], in which the Zn(II)-sensitized near-infrared luminescent performances in the four complexes 2-5 are closely related to their structural models.