Synthesis and protonation reactions of nitrosyl complexes [M2Cp (μ-κ:η5 -C5H4)(μ-PR2)(CO)(NO)2] to give κ:η-NO-bridged derivatives (M = Mo, W
The title compounds were prepared upon reaction of BAr’4 − salts of the known cations [M2Cp2(μ-PR2) (CO)2(NO)2] + (M = Mo, W; R = Cy, t Bu; Ar’ = 3,5-C6H3(CF3)2), with commercial Me3NO⋅2H2O in fluorobenzene solution at 273 K, this promoting decarbonylation and cyclopentadienyl deprotonation to yield...
| Autores: | , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2024 |
| País: | España |
| Recursos: | Universidad de Oviedo (UNIOVI) |
| Repositorio: | RUO. Repositorio Institucional de la Universidad de Oviedo |
| Idioma: | inglés |
| OAI Identifier: | oai:digibuo.uniovi.es:10651/79514 |
| Acesso em linha: | https://hdl.handle.net/10651/79514 https://dx.doi.org/10.1016/j.jorganchem.2024.123475 |
| Access Level: | acceso abierto |
| Resumo: | The title compounds were prepared upon reaction of BAr’4 − salts of the known cations [M2Cp2(μ-PR2) (CO)2(NO)2] + (M = Mo, W; R = Cy, t Bu; Ar’ = 3,5-C6H3(CF3)2), with commercial Me3NO⋅2H2O in fluorobenzene solution at 273 K, this promoting decarbonylation and cyclopentadienyl deprotonation to yield complexes with cyclopentadienylidene ligands bridging the metal centres (W− W = 2.9917(5) Å when R = Cy). The use of dichloromethane as solvent, however, triggered a competitive chloride abstraction reaction by the Mo compounds that yielded the chloride complexes [Mo2Cp2Cl(μ-PR2)(CO)(NO)2], specifically formed with an anti disposition of the Cp ligands relative to the Mo2P plane, and cis positioning of carbonyl and chloride ligands relative to the P atom (Mo− Cl = 2.336(4) Å when R = t Bu). Protonation of the cyclopentadienylidene-bridged complexes with [H(OEt2)2](BAr’4) yielded the BAr’4 − salts of the dicyclopentadienyl cations [M2Cp2(μ-κ:η-NO) (μ-PR2)(CO)(NO)]+ (Mo− Mo = 3.1027(2) Å when R = t Bu; W− W = 3.0446(7) Å when R = Cy), which display bridging nitrosyl ligands in the rare linear end-on:side-on coordination mode, and are kinetic rather than thermodynamic products, according to density functional theory calculations. When using HBF4⋅OEt2 as protonation reagent on the Pt Bu2-bridged complexes, however, coordination of the external anion (in the κ1 -mode) also takes place, to yield the tetrafluoroborate complexes [M2Cp2(κ1 -BF4)(μ-Pt Bu2)(CO)(NO)2] as unique (Mo) or major (W) products. Methylation of the same cyclopentadienylidene complexes with [Me3O](BF4) was only observed for the tungsten cation, and took place specifically at the O atom of one nitrosyl ligand to give [W2Cp(μ-κ:η5 -C5H4) (NOMe)(μ-Pt Bu2)(CO)(NO)](BF4), a complex displaying a linear methoxyimido ligand (W− N = 1.746(4) Å; W− N− O = 163.5(4)o ). |
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