The synthesis of (PNP)Re(N)X (PNP = [2-P(CHMe₂)₂-4-MeC₆H₃]₂N, X = Cl and Me) complexes is described. The methylnitridorhenium complex 3 was found to react differently with CO and isocyanides, leading to the isolation of a Re(V) acyl complex 4 and an isocyanide adduct 6. Two parallel pathways were observed for the reaction of 3 with CO: (1) CO inserts into the Re–Me bond to afford 4, and (2) 3 isomerizes by distortion of the aryl backbone of the PNP ligand to afford the isomer 3′. This is followed by the reaction of 3′ with CO to afford the tricarbonyl complex 5, which was fully characterized. The contrasting reaction of 3 with 2,6-dimethylphenyl isocyanide lends further support for the proposed isomerization pathway. DFT (M06) calculations suggest that insertion of CNR into the Re–Me bond (27.2 kcal mol⁻¹) is inaccessible at room temperature. Instead the substrate adds to the metal center via the most accessible face i.e. syn to the rhenium–nitrido bond, to afford 6. The addition of CO to isomer 3′ is proposed to proceed with a similar mechanism to 2,6-dimethylphenyl isocyanide.

中文翻译：

---

含有PNP配体的 高价氮or（v）配合物：配体柔韧性的影响†

描述了（PNP）Re（N）X（PNP = [2-P（CHMe ₂）₂ -4-MeC ₆ H ₃ ] ₂ N，X = Cl和Me）配合物的合成。发现甲基氮化or络合物3与CO和异氰化物的反应不同，从而导致Re（V）酰基络合物4和异氰化物加合物6的分离。对于3与CO的反应，观察到两个平行的途径：（1）CO插入Re-Me键得到4，（2）3通过PNP配体的芳基骨架变形而异构化，得到异构体3'。随后3'与CO反应得到三羰基配合物5，其已被充分表征。3与2，6-二甲基苯基异氰化物的对比反应为拟议的异构化途径提供了进一步的支持。DFT（M06）的计算表明，在室温下无法将CNR插入Re-Me键（27.2 kcal mol ^-1）。取而代之的是，基材通过最易接近的面（即syn-氮键的同位基）添加到金属中心，得到6。提议将CO加到异构体3'中以与2，6-二甲基苯基异氰化物相似的机理进行。