Figure 5. Molecular packing of a crystal of 1.

Crystalline packing of molecules of 1 in the low- and high-temperature phase (1—123 K and 1—303 K) as viewed from (a) the (010) face and (b) the (001) face. From the low-temperature phase to the high-temperature phase (a) the size of the n-butyl group in the direction perpendicular to the molecular plane (d_m), the average distance between the molecules along the c axis (d_c) and the length of the crystal c axis (ι_c) increase to 2.724 Å (d_m′), 3.550 Å (d_c′) and 8.178 Å (ι_c′), respectively; the tilt angle ϕ (Supplementary Fig. 2) decreases from 61.65 to 60.25° (ϕ′, Supplementary Fig. 3); (b) the size of each molecular column decreases from 13.130 to 12.440 Å (ι_b→ι_b′) along the b axis; and the crossing angle ω (Supplementary Fig. 2) decreases to 65.73° (ω′, Supplementary Fig. 3). The outlines of the crystal morphology and red arrows in the middle of the diagrams show the direction of contraction and expansion of the crystal, respectively. Green, Co; grey, C; white, H; blue, N; red, O.