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Interaction between Anions and Molybdenum Allyl Dicarbonyl Complexes of 1,4,7‐Trithiacyclononane
Author(s) -
Morales Dolores,
Puerto Marcos,
del Río Ignacio,
Pérez Julio,
López Ramón
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201201327
Subject(s) - chemistry , thioether , steric effects , allyl bromide , medicinal chemistry , ligand (biochemistry) , molybdenum , adduct , substituent , iodide , octahedron , bromide , crystallography , stereochemistry , crystal structure , inorganic chemistry , organic chemistry , biochemistry , receptor
Abstract The labile complex [MoCl(η 3 ‐methallyl)(CO) 2 (NCMe) 2 ] reacts with the ligand 1,4,7‐trithiacyclononane ([9]aneS 3 ) and the salt NaBAr′ 4 to afford [Mo(η 3 ‐methallyl)(CO) 2 ([9]aneS 3 )][BAr′ 4 ] ( 1⋅BAr′ 4 ). An analogous reaction of [MoBr(η 3 ‐allyl)(CO) 2 (NCMe) 2 ] yields [Mo(η 3 ‐allyl)(CO) 2 ([9]aneS 3 )][BAr′ 4 ] ( 2⋅BAr′ 4 ). The new compounds 1⋅BAr′ 4 and 2⋅BAr′ 4 were characterized by IR and NMR spectroscopic analysis and X‐ray diffraction studies. Both compounds feature the cyclic thioether [9]aneS 3 coordinated as a tridentate ligand to the molybdenum center. The allyl ligand in 2⋅BAr′ 4 is aligned with the middle of the OC‐Mo‐CO angle, which is acute. Both of these features are typical of most pseudo‐octahedral allyl dicarbonyl molybdenum complexes. In contrast, the allyl group is rotated in 1⋅BAr′ 4 , which is attributed to steric hindrance between the methyl substituent and the ligated thioether, and the OC‐Mo‐CO angle is obtuse. Compound 1⋅BAr′ 4 undergoes rapid substitution of [9]aneS 3 by either chloride and fluoride ions in dichloromethane, and the products include the known species [{Mo(η 3 ‐methallyl)(CO) 2 } 2 (μ‐Cl) 3 ] − and a structurally similar new anionic complex with two fluoro and one hydroxo bridging ligands, respectively. Stable supramolecular adducts were formed in the reactions of 1⋅BAr′ 4 and 2⋅BAr 4 with bromide, iodide, hydrogensulfate, and methanesulfonate compounds. The binding constants of these adducts in dichloromethane were calculated from 1 H NMR spectroscopic titration data, and the solid‐state structures of the 1⋅Br , 1⋅HSO 4 , 1⋅I , and 2⋅I adducts were determined by X‐ray diffraction studies. The surprising slightly higher stability of the iodide adduct relative to that of bromide was investigated theoretically, with the results pointing to an effect of the differential solvation of the halide ions.