Phonsri Wasinee, Harding Phimphaka, Liu Lujia, Telfer Shane G, Murray Keith S, Moubaraki Boujemaa, Ross Tamsyn M, Jameson Guy N L, Harding David J
Functional Materials and Nanotechnology Centre of Excellence (FuNTech) , Walailak University , Thasala , Nakhon Si Thammarat 80160 , Thailand . Email:
MacDiarmid Institute for Advanced Materials and Nanotechnology , Institute of Fundamental Sciences , Massey University , Palmerston North , New Zealand.
Chem Sci. 2017 May 1;8(5):3949-3959. doi: 10.1039/c6sc05317c. Epub 2017 Mar 23.
Solvent effects in a series of Fe(iii) spin crossover (SCO) complexes [Fe(qsal-I)]OTf·sol (sol = MeOH , EtOH , -PrOH , i-PrOH , acetone and MeCN ) are explored. SCO is abrupt in (following MeOH loss) and , gradual for ( = 199 K) and ( = 251 K) and incomplete, even up to 350 K, for and . In [Fe(qsal-I)]OTf SCO occurs at ↓ = 225 K and ↑ = 234 K (Δ = 9 K), while aged samples of exhibit an exceptionally wide hysteresis of 80 K (↓ = 139 K and ↑ = 219 K). In contrast, fresh samples of exhibit stepped SCO with hysteresis varying from 2 to 42 K. VT-PXRD (variable temperature powder X-ray diffraction) studies indicate a new phase, , is formed upon cooling below 180 K along with a minor LS phase . Phase and the HS phase undergo a spin transition at ↓ = 180 K and ↑ = 215 K with phase exhibiting two-step SCO. Structural studies in both spin states, except , show the cations are linked through extensive π-π interactions to form 1D chains. A combination of P4AE (parallel fourfold aryl embrace) and I···X (X = I, O, π) interactions create tightly packed 3D supramolecular networks. This study emphasizes that while solvent may result in only small structural changes SCO characteristics can be impacted dramatically.
研究了一系列铁（III）自旋交叉（SCO）配合物[Fe(qsal-I)]OTf·sol（sol = 甲醇、乙醇、正丙醇、异丙醇、丙酮和乙腈）中的溶剂效应。在[Fe(qsal-I)]OTf·甲醇和[Fe(qsal-I)]OTf·乙醇中，SCO是突然发生的（在失去甲醇后），在[Fe(qsal-I)]OTf·正丙醇（Tc = 199 K）和[Fe(qsal-I)]OTf·异丙醇（Tc = 251 K）中是逐渐发生的，而在[Fe(qsal-I)]OTf·丙酮和[Fe(qsal-I)]OTf·乙腈中，即使到350 K也是不完全的。在[Fe(qsal-I)]OTf中，SCO发生在Tc↓ = 225 K和Tc↑ = 234 K（Δ = 9 K），而老化的[Fe(qsal-I)]OTf·乙腈样品表现出异常宽的80 K滞后（Tc↓ = 139 K和Tc↑ = 219 K）。相比之下，新鲜的[Fe(qsal-I)]OTf·丙酮样品表现出阶梯状SCO，滞后范围为2至42 K。变温粉末X射线衍射（VT-PXRD）研究表明，在冷却至180 K以下时会形成一个新相α，同时还有少量的低自旋（LS）相β。α相和高自旋（HS）相γ在Tc↓ = 180 K和Tc↑ = 215 K发生自旋转变，α相表现出两步SCO。除[Fe(qsal-I)]OTf·乙腈外，对两种自旋态的结构研究表明，阳离子通过广泛的π-π相互作用连接形成一维链。平行四重芳基包围（P4AE）和I···X（X = I、O、π）相互作用的组合形成了紧密堆积的三维超分子网络。这项研究强调，虽然溶剂可能只导致很小的结构变化，但SCO特性可能会受到显著影响。
