CoIII(S2CNR2)3 (R = Et, cyclohexyl) complexes were electrochemically oxidised by one-electron in CH2Cl2 containing Bu4NPF6 as the supporting electrolyte. Voltammetric, EPR and UV-VIS-NIR spectroscopic data indicated that the cation complexes, [CoIV(S2CNR2)3]+, formed by oxidation of the parent CoIII compounds were stable for at least several hours at low temperatures (T
= 233 K), although instability was evident at higher temperatures and/or longer times. EPR spectroscopic data obtained by in situ electrogeneration of the oxidised species at low temperatures indicated that the unpaired electron largely resided on the metal centre, thereby confirming a formally CoIV state. The UV-VIS-NIR spectra of the [CoIV(S2CNR2)3]+
complexes showed a new set of low energy and moderate intensity series of bands at ν
= 9600, 13300 and 15500 cm−1 (ε
= 700–1500 L cm−1 mol−1) which were interpreted as ligand-to-metal charge transfer excitations to the unfilled t2g orbital. The EPR spectra of [CoIV(S2CNR2)3]+ (g//
≈ 2.65 and g⊥
≈ 1.90) required low temperatures to be detected (T < ca. 50 K) and displayed a high degree of anisotropy consistent with a distorted octahedral structure.
CoIII(S2CNR2)3(R = Et,环己基)配合物在含有 Bu4NPF6 作为支撑电解质的
CH2Cl2 中被一电子电
化学氧化。伏安法、EPR 和紫外-可见-近红外光谱数据表明,母体 CoIII 化合物氧化形成的阳离子配合物 [CoIV(S2CNR2)3]+ 在低温(T = 233 K)条件下至少能稳定几个小时,但在较高温度和/或较长时间条件下则明显不稳定。通过在低温下对氧化物进行原位电生成而获得的 EPR 光谱数据表明,未配对的电子主要停留在
金属中心,从而确认了正式的 CoIV 状态。CoIV(S2CNR2)3]+ 复合物的紫外-可见-近红外光谱在 ν = 9600、13300 和 15500 cm-1 (ε = 700-1500 L cm-1 mol-1)处显示了一组新的低能量、中等强度的带,这组带被解释为
配体对未填充 t2g 轨道的
金属电荷转移激发。CoIV(S2CNR2)3]+(g// ≈ 2.65 和 g⊥ ≈ 1.90)的 EPR 光谱需要在低温下才能检测到(T < 约 50 K),并显示出与扭曲的八面体结构相一致的高度各向异性。