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

Abstract

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 200K. Below this temperature, 1b displays nearly 50% one-step transition. The first transition of 1a starts below ca. 280K and almost completes at ca. 210K. Below around 120K, second transition starts and completes around 65K, which 50% of high-spin is remaining. Interlayer spaces between two dimensional sheets are greater than other similar 2D Hoffman-like clathrates.