Guest-dependent spin transition with long range intermediate state for 2-dimensional Hofmann-like coordination polymer

•New FeII guest-dependent spin crossover (SCO) coordination polymer has been prepared and investigated.•Our compound shows the broad temperature-range intermediate state.•Our findings suggested the designing of crystal packing of Hofmann type coordination polymer can be achieved.

New FeII guest-dependent spin crossover (SCO) coordination polymers, {FeII4-(3-pentyl)pyridine2[AuI(CN)2]2·(guest)}n (guest = 4-(3-pentyl)pyridine (1a), non-guest (1b)) has been prepared and investigated by magnetic measurement and X-ray structure analysis. The adsorbed state has a two-step transition with a broad temperature-range intermediate state, whereas the desorbed state has a one-step transition. 1b is maintained HS state down to around 200 K. Below this temperature, 1b displays nearly 50% one-step transition. The first transition of 1a starts below ca. 280 K and almost completes at ca. 210 K. Below around 120 K, second transition starts and completes around 65 K, which 50% of high-spin is remaining. Interlayer spaces between two dimensional sheets are greater than other similar 2D Hoffman-like clathrates.

Graphical abstractThe new SCO coordination polymer with/without guest molecules has been constructed and investigated by magnetic measurement and X-ray structure analysis. Adsorbed state has two-step transitions with long intermediate state and desorbed state has one-step transition. Host molecule dramatically stabilize the intermediate state.Figure optionsDownload full-size imageDownload as PowerPoint slide