The first porous molecular conductor (PMC), which exhibits porosity, a through-space conduction pathway and rich charge carriers (electrons), was prepared through electrocrystallization from Cd2+ and N,N′-di­(4-pyridyl)-1,4,5,8-naphthalenetetracarboxdiimide (NDI-py). [Cd­(NDI-py)­(OH2)4]­(NO3)1.3±0.1·nDMA (PMC-1) was assembled by π–π stacking among one-dimensional (1D) linear coordination polymers. The NDI cores were partially reduced into radical anions to form conductive π-stacked columns, yielding (1.0–3.3) × 10–3 S cm–1 at room temperature. Moreover, the electrical conductivity was significantly enhanced by removing the solvent molecules from PMC-1, indicating that PMCs are promising as molecule-responsive conductive materials.

Anionic Keggin polyoxometalates (POMs) and ether linkage-enriched ammonium ions spontaneously self-assemble into rectangular ultrathin nanosheets in aqueous media. The structural flexibility of the cation is essential to form oriented nanosheets; as demonstrated by single-crystal X-ray diffraction measurements. The difference in initial conditions exerts significant influence on selecting for self-assembly pathways in the energy landscape. Photoillumination of the POM sheets in pure water causes dissolution of reduced POMs, which allowed site-specific etching of nanosheets using laser scanning microscopy. By contrast, photoetching was suppressed in aqueous AgNO and site-selective deposition of silver nanoparticles occurred as a consequence of electron transfer from the photoreduced POMs to Ag ions on the nanosheet surface.

A Br-bridged Pd chain complex with the Pd ion in an uncommon +3 oxidation state, [Pd(dabdOH)Br]Br (3), was prepared using a new method involving multiple hydrogen bonds. The PdBr chain complex exhibited superior electrical conductivity and thermal stability. An in-plane ligand with an additional hydrogen donor group (hydroxy group), (2S,3S)-2,3-diaminobutane-1,4-diol (dabdOH), was used to create a multiple-hydrogen-bond network, which effectively shrinks the Pd-Br-Pd distance, stabilizing the Pd(III) state up to its decomposition temperature (443 K). 3 shows semiconducting behavior with quite high electrical conductivity (3-38 S cm at room temperature), which is 10 times larger than the previous record for analogous PdBr chains. Indeed, 3 is the most conductive MX-type chain complex reported so far. The precise positional control of ions via a multiple-hydrogen-bond network is a useful method for controlling the electronic states, thermal stability and conductivity of linear coordination polymers.

A neutral mononuclear Fe(III) complex [Fe(III) (H-5-Br-thsa-Me)(5-Br-thsa-Me)]⋅H2 O (1; H2 -5-Br-thsa-Me=5-bromosalicylaldehyde methylthiosemicarbazone) was prepared that exhibited a three-step spin-crossover (SCO) with symmetry breaking and a 14 K hysteresis loop owing to strong cooperativity. Two ordered intermediate states of 1 were observed, 4HS-2LS and 2HS-4LS, which exhibited reentrant phase-transition behavior. This study provides a new platform for examining multistability in SCO complexes.