Synthesis and structural characterization of the isomers of (1-phosphino-?3-pentenyl)tricarbonylmanganese
Por:
Paz-Sandoval M.A., Juárez Saavedra P., Zúñiga Villarreal N., Rosales Hoz M.J., Joseph-Nathan P., Ernst R.D., Arif A.M.
Publicada:
1 ene 1992
Resumen:
Diphenylphosphine reacts with ?5-pentadienyltricarbonylmanganese (1) to give isomers Mn[P-(Ph)2CH2-?3-CHCHCHCH 3](CO)3 (2) and Mn[P(Ph)2CH2CH2-?3-CHCHCH 2](CO)3 (3). In both cases, phosphorus is added stereoselectively to the terminal carbon atom. Single-crystal X-ray diffraction studies of 2 and 3 confirm the unprecedented formation of the novel [1-(diphenylphosphino)-?3-pentenyl]tricarbonylmanganese complexes in which the phosphahexenyl ligand is bonded to the manganese center through an ?3 interaction and also by phosphorus coordination affording six- and seven-membered "pseudo"-ring structures. Crystals of 2 are orthorhombic, space group Pna21 with a = 8.844 (1) Å, b = 16.806 (2) Å, c = 12.629 (1) Å, and Z = 4. The structure was refined to discrepancy indices of R = 0.0596 and Rw = 0.0602 for 1468 reflections having I > 3?(I). Crystals of 3 are monoclinic, space group P21/a, with a = 10.630 (7) Å, b = 11.979 (8) Å, c = 14.27 (1) Å, ? = 92.32 (6)°, and Z = 4. The structure was refined to discrepancy indices of R = 0.0641 and Rw = 0.0712 for 1735 reflections having I > 3?(I). The two complexes have distorted-octahedral geometries with important differences both in lengths within the phosphino-?3-pentenyl systems and for the bonding parameters of the manganese ions. The metal carbonyl distances also show significant differences from one complex to the other. Monitoring of the reaction by IR and NMR (31P, 1H) spectroscopy showed that the addition of PHPh2 to 1 proceeds by initial conversion to 2 and subsequent formation of 3, with no evidence for preliminary interaction at either the manganese center or one of the CO carbon atoms. The reactions of cis-MnBr(CO)4PHPh2 (7a) and fac-MnBr-(CO)3(PHPh2)2 (8a) with C5H7SnBu3 to initially afford compound 2, are also discussed. The crystal of 7a is monoclinic, space group P21/c with a = 11.325 (5) Å, b = 10.342 (3) Å, c = 14.813 (5) Å, ? = 95.08 (3)°, and Z = 4. The structure was refined to values of R = 0.0495 and Rw = 0.0540 for 2001 reflections with I > 3?(I). The complex has a pseudooctahedral geometry with the bromine and diphenylphosphine ligands cis to each other. © 1992 American Chemical Society.
Filiaciones:
Departamento de Quimica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado 14-740, D.F. 07000, México, Mexico
Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
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