The magnetic properties of the spin-crossover compounds, [Fe(qsal)2]NCSeâMeOH (1) and [Fe(qsal)2]NCSeâCH2Cl2 (2), have been measured. We have discovered that both compounds 1 and 2 exhibit a wide thermal hysteresis loop of 140 K (T1/2↑=352 K and T1/2↓=212 K) and 180 K (T1/2↑=392 K and T1/2↓=212 K), respectively, in the first cycle. Thermogravimetric analysis shows that solvent molecules escape from compounds 1 and 2 around 340 and 395 K, respectively. This means that the hysteresis loops observed for the first cycle are only apparent ones. Following the first loop, they show a two-step spin-crossover in warming mode. The so-called "step 1" and "step 2" are centered around T1/2(S1)↑=215 K and T1/2(S2)↓=282 K, respectively. On the other hand, a one-step spin-crossover occurs at T1/2↓=212 K in cooling mode. The hysteresis widths can be estimated to be 3 K (step 1) and 70 K (step 2), assuming that the widths in steps 1 and 2 are defined as the differences between T1/2(S1)v and T1/2↑, and T1/2(S2)↓ and T1/2↓, respectively. The hysteresis width of 70 K in step 2 is one of the widest values reported so far for spin-crossover complexes. It is thought that the cooperativity operating in the complexes arises mainly from the intermolecular ð interactions between quinoline and phenyl rings. Using a previously repored model, we are able to simulate the hysteresis loop with a two-step spin-crossover in warming mode and a one-step transition in cooling mode.

A dipping method was developed to fabricate three-dimensional colloidal crystal films. The thickness of the films fabricated by this method can be precisely controlled from one layer to several tens of layers by controlling the particle concentration and the film formation speed. Experimental results showed that the spheres form a face-centered cubic structure and that single crystals in the film can extend to centimeter dimensions.

Learning from nature to design the materials of the future. The cover picture shows the Morpho butterfly, whose wings displays structural color, and lotus leaves, which exhibit hydrophobicity. To mimic these natural products, materials were prepared that utilize the unique structural properties of an inverse opal film, which displays uniform structural colors and a surface with well-ordered bumps that aid hydrophobicity. Modification leads to a superhydrophobic surface with a large water-contact angle. For more information see the Communication by O. Sato et al. on page 894 ff.