The first examples of azole-triazole Rat ligands, bidentate L4NMeIm(3-(1-methyl-1H-imidazol-4-yl)-5-phenyl-4-(p-tolyl)-4H-1,2,4-triazole) and L4SIm (4-(5-phenyl-4-(p-tolyl)-4H-1,2,4-triazol-3-yl)thiazole), have been prepared, by extension of the general synthesis used to access many examples of azine-triazoles. The tris-L FeII complexes of the azine-triazoles are consistently low spin (LS). As intended, these new azole-triazole ligands provide lower field strengths, resulting in high-spin (HS) [FeII(L4NMeIm)3](BF4)2 (1·4H2O) and spin crossover (SCO) active [FeII(L4SIm)3](BF4)2 (2·0.5H2O). Single-crystal structure determinations revealed that at 100 K 1·solvents is HS whereas 2·solvents is LS. Solid-state variable temperature magnetic studies of air-dried crystals showed that the methylimidazole-triazole complex 1·4H2O remains HS while the thiazole-triazole complex 2·0.5H2O undergoes a two-step gradual SCO (T1/2 approximately 275 and 350 K). Variable-temperature Evans method NMR studies of 2, in five different solvents (CD3NO2, CD3CN, CD3COCD3, CD2Cl2, and CDCl3) gave T1/2 values in a relatively narrow range, 214-259 K. These T1/2 values did not correlate with the solvent polarity index P' (R2 = 0.25) but did correlate with the solvent basicity parameter SB (R2 = 0.90). Variable-temperature UV-vis studies on a golden yellow CH3CN solution of 2, with monitoring of the d-d transition at 530 nm (ε = 39 L mol-1 cm-1 at 293 K) while the solution was heated from 253 to 303 K, showed that the high-spin fraction increased from 0.51 to 0.77. Cyclic voltammetry studies in CH3CN revealed a Fe(III)/Fe(II) redox process that was reversible for 1 and irreversible for 2, with significant tuning of the Epa value: the methylimidazole-triazole complex 1 is significantly easier to oxidize (0.46 V) than the thiazole-triazole complex 2 (0.68 V; both vs 0.01 M Ag/AgNO3).

中文翻译：

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扩展叠氮三唑合成到叠氮三唑减少配体场，导致Tris-L Fe（II）中的自旋交叉。

唑-三唑大鼠配体的第一个例子是双齿L4NMeIm（3-（1-甲基-1H-咪唑-4-基）-5-苯基-4-（对甲苯基）-4H-1,2,4-三唑）和L4SIm（4-（5-苯基-4-（对甲苯基）-4H-1,2,4-三唑-3-基）噻唑）已经制备，通过扩展通用的合成方法获得了许多嗪-三唑的实例。嗪-三唑的tris-L FeII配合物始终是低自旋（LS）。如预期的那样，这些新的唑-三唑配体提供较低的场强，从而产生高旋转（HS）[FeII（L4NMeIm）3]（BF4）2（1·4H2O）和自旋交联（SCO）活性[FeII（L4SIm） 3]（BF4）2（2·0.5H2O）。单晶结构测定表明，在100 K下1·溶剂为HS，而2·溶剂为LS。空气干燥晶体的固态可变温度磁研究表明，甲基咪唑-三唑复合物1·4H2O保持HS，而噻唑-三唑复合物2·0.5H2O经历两步逐步SCO（T1 / 2约为275和350 K ）。在5种不同溶剂（CD3NO2，CD3CN，CD3COCD3，CD2Cl2和CDCl3）中对2进行的变温Evans方法NMR研究表明，T1 / 2值在214-259 K的相对狭窄范围内。这些T1 / 2值不相关溶剂极性指数为P'（R2 = 0.25），但与溶剂碱性参数SB（R2 = 0.90）相关。在2的金黄色CH3CN溶液上进行可变温度UV-vis研究，在溶液从253加热到303 K的同时，在530 nm处监测dd跃迁（在293 K下ε= 39 L mol-1 cm-1） ，表明高旋转分数从0.51增加到0.77。