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Unique homoleptic cyclic tetranuclear Ln(4)(Salen)(4) complexes [Ln(4)(L)(2)(HL)(2)(μ(3)-OH)(2)Cl(2)]·2Cl (Ln = Nd, 1; Ln = Yb, 2; Ln = Er, 3; Ln = Gd, 4) or Ln(4)(Salen)(2) complexes [Ln(4)(L)(2)(μ(3)-OH)(2)(OAc)(6)] (Ln = Nd, 5; Ln = Yb, 6; Ln = Er, 7; Ln = Gd, 8) have been self-assembled from the reaction of the hexadentate Salen-type Schiff-base ligand H(2)L with LnCl(3)·6H(2)O or Ln(OAc)(6)·6H(2)O (Ln = Nd, Yb, Er, or Gd), respectively (H(2)L: N,N'-bis(salicylidene)cyclohexane-1,2-diamine). The result of their photophysical properties shows that the strong and characteristic NIR luminescence for complexes 1-2 and 5-6 with emissive lifetimes in microsecond ranges are observed, and the sensitization arises from the excited state (both (1)LC and (3)LC) of the hexadentate Salen-type Schiff-base ligand with the flexible linker. Temperature dependence (1.8-300 K) magnetic susceptibility studies of the eight complexes suggest the presence of an antiferromagnetic interaction between the Ln(3+) ions.

Plenty of molecular circuits with specific functions have been developed; however, logic units with reconfigurability, which could simplify the circuits and speed up the information process, are rarely reported. In this work, we designed a novel reconfigurable logic unit based on a DNA-templated, potassium-concentration-dependent, supramolecular assembly, which could respond to the input stimuli of H and K . By inputting different concentrations of K , the logic unit could implement three significant functions, including a half adder, a half subtractor, and a 2-to-4 decoder. Considering its reconfigurable ability and good performance, the novel prototypes developed here may serve as a promising proof of principle in molecular computers.

The mol­ecule of the title compound, C23H18Cl2N4O, assumes a non-planar conformation in which the pyrazolone ring forms dihedral angles of 32.61 (19), 76.73 (14) and 52.57 (19)° with the three benzene rings. The secondary amino group is involved in an intra­molecular N—H⋯O hydrogen bond. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers. An offset stacking inter­action is observed between the chloro-substituted benzene rings protruding on both sides of these dimers [centroid–centroid distance = 3.862 (1) Å].

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