Synthesis and characterization of Co and Ni complexes stabilized by keto- and acetamide-derived P,O-type phosphine ligands
作者:Magno Agostinho、Vitor Rosa、Teresa Avilés、Richard Welter、Pierre Braunstein
DOI:10.1039/b814284j
日期:——
The coordination properties of the β-keto phosphine ligands R2PCH2C(O)Ph (HL11, R = i-Pr; HL22, R = Ph), of the new acetamide-derived phosphine ligand (i-Pr)2PNHC(O)Me (HL33) and of Ph2PNHC(O)Me (HL44) have been examined towards Ni(II) complexes. Comparisons are made between systems in which the PCH2 function of the ketophosphine has been replaced with an isoelectronic PNH group in amide-derived ligands, or the PCH functionality of phosphinoenolates with a PN group in phosphinoiminolate complexes. Furthermore, ligands HL22 and HL44 reacted with [(η5-C5H5)CoI2(CO)] to afford the phosphine mono-adducts [(η5-C5H5)CoI2Ph2PCH2C(O)Ph}] (1) and [(η5-C5H5)CoI2Ph2PNHC(O)Me}] (3), respectively, which upon reaction with excess NEt3 yielded the phosphinoenolate complex [(η5-C5H5)CoIPh2PCHC(O)Ph}] (2) and the phosphinoiminolate complex [(η5-C5H5)CoIPh2PNC(O)Me}] (4), respectively. The complexes cis-[Ni(i-Pr)2PNC(O)Me}2] (6) and cis-[NiPh2PNC(O)Me}2] (7) were obtained similarly from NiCl2 and HL3 and HL4, respectively, in the presence of a base. The phosphinoenolate complex [Ni(i-Pr)2PCHC(O)Ph}2] (5) exists in ethanol as a mixture of the cis and trans isomers, in contrast to cis-[Ni(Ph2PCHC(O)Ph}2], and the solid-state structure of the trans isomer of 5 was established by X-ray diffraction. The structures of the ligand HL3 and of the complexes 1, 3 in 3·3/2CH2Cl2, 4, 6 and 7 have also been determined by X-ray diffraction and are compared with those of related complexes. Complexes 4, 6 and 7 contain a five-membered heteroatomic metallocyclic moiety, which is constituted by five different chemical elements. The structural consequences of the steric bulk of the P substituents and of the electronic characteristics of the P,O chelates are discussed.
新型乙酰胺衍生膦配体 (i-Pr)2PNHC(O)Me 的 β-酮基膦配体 R2PCH2C(O)Ph (HL11, R = i-Pr; HL22, R = Ph) 的配位特性 ( HL33) 和 Ph2PNHC(O)Me (HL44) 已针对 Ni(II) 配合物进行了研究。对其中酮膦的 PCH2 官能团被酰胺衍生配体中的等电子 PNH 基团取代的系统,或膦烯醇化物的 PCH 官能团与亚氨基膦配合物中的 PN 基团取代的系统进行了比较。此外,配体 HL22 和 HL44 与 [(η5-C5H5)CoI2(CO)] 反应,得到膦单加合物 [(η5-C5H5)CoI2Ph2PCH2C(O)Ph}] (1) 和 [(η5-C5H5) )CoI2Ph2PNHC(O)Me}] (3),分别与过量的 NEt3 反应生成膦基烯醇盐络合物 [(η5-C5H5)CoIPh2PCHC(O)Ph}] (2) 和膦亚氨基盐络合物 [(分别为 η5-C5H5)CoIPh2PNC(O)Me}] (4)。配合物 cis-[Ni(i-Pr)2PNC(O)Me}2] (6) 和 cis-[NiPh2PNC(O)Me}2] (7) 类似地由 NiCl2 和 HL3 和 HL4 获得,分别在存在碱基的情况下。膦烯醇盐络合物 [Ni(i-Pr)2PCHC(O)Ph}2] (5) 以顺式和反式异构体的混合物形式存在于乙醇中,与 cis-[Ni(Ph2PCHC(O)Ph}) 不同2],通过X射线衍射建立了5的反式异构体的固态结构,还确定了配体HL3和3·3/2CH2Cl2中配合物1、3、4、6和7的结构。通过 X 射线衍射测定,并与相关配合物 4、6 和 7 的配合物进行了比较,该配合物包含由五种不同化学元素组成的五元杂原子金属环部分。讨论了 P,O 螯合物的取代基和电子特性。