Anomalous dielectric behavior and thermal motion of water molecules confined in channels of porous coordination polymer crystals.

Guest water molecules confined in channels of porous coordination polymer crystals [Ln(2)Cu(3)(IDA)(6)]·nH(2)O (Ln = La, Nd, Sm, Gd, Ho, Er; IDA = [NH(CH(2)COO)(2)](2-); n ≈ 9) exhibited large dielectric constants (ε) and antiferroelectric behaviors at high temperatures (e.g., ε(Sm) ≈ 1300 at 400 K). In addition, plots of the temperature dependence of ε showed broad peaks at ∼170 K, below which ε became very small. These puzzling temperature dependences of ε are consistent with the results of molecular dynamics simulations, suggesting the "freezing of thermal motion" of water molecules at ∼170 K.

Evidence of the chemical uniaxial strain effect on electrical conductivity in the spin-crossover conducting molecular system: [Fe(III)(qnal)2][Pd(dmit)2]5.acetone.

A novel spin-crossover molecular conductor, [Fe(qnal)2][Pd(dmit)2]5.acetone, was prepared and characterized. The crystal structural analyses of both the low- and high-temperature phases revealed that the supramolecular pi-pi interactions between the spin-crossover Fe(qnal)2 cations as well as the cation contraction play an important role in the uniaxial lattice deformation which will modulate the electrical conductivity of the conducting Pd(dmit)2 layer.

Electrical conductivity modulation coupled to a high-spin-low-spin conversion in the molecular system [FeIII(qsal)2][Ni(dmit)2]3.CH3CN.H2O.

The synergy between the electrical conductivity within the stacks of Ni(dmit)2 in the newly electrocrystallized [Fe(qsal)2][Ni(dmit)2]3.CH3CN.H2O and the spin conversion of Fe(qsal)2 is evidenced. In addition, the presence of a light-induced excited spin state trapping effect suggests that this complex is a prototypal photoswitchable spin-crossover molecular conductor.