η3-Allyl molybdenum dithiophosphate and dithiophosphinate complexes with uni- and bidentate nitrogen donor ligands. X-ray structure of [Mo2(η3-C3H5)2(CO)4{S2P(OEt)2}2(μ-NH2NH2)]

Synthesis of Molybdenum Dicarbonyl Complexes Bearing Tethered Homoallylic Amines and Sulfides

“…The X-ray structures obtained for complexes 8 (Figure ) and 14 (Figure ), which both contain a coordinating heteroatom moiety as part of the tridentate π-allyl ligand, show identical arrangements of ligands around the molybdenum atom as the related (π-allyl)dicarbonylmolybdenum complexes bearing a bidentate ligand reported by Miguel. , The open face of the allyl moiety is directed toward the two carbonyls, as has been found in other (π-allyl)dicarbonylmolybdenum complexes and refined using full-matrix least-squares on F 2 .…”

Coupling of η3-Allyl and Alkyne in Molybdenum Carbonyl Complexes

“…The compounds were identified by the (M − MeCN) + peaks, which showed the typical isotopic pattern of molybdenum. The spectroscopic features of 1c,d are similar to those found for the complexes containing unsubstituted allyls 1a,b , and accordingly, it has been assumed for them the same structure, which was supported by the structural determination of the hydrazine derivative [{Mo(η 3 -C 3 H 5 )(CO) 2 {S 2 P(OEt) 2 }} 2 (μ-NH 2 NH 2 )] …”

“…In contrast, complexes 1a,b , bearing unsubstituted allyl, exhibit only one signal for the two carbonyls. The same occurs with other related complexes although, according to X-ray crystallography, they contain two inequivalent carbonyl ligands in the solid. , A trigonal-twist process has been invoked to account for the equilibration of the two inequivalent CO groups in the NMR time scale. This process consists of the rotation of the triangular face formed by two CO's and one allyl ligand, this being a structural feature commonly found in η 3 -allyl dicarbonyl complexes .…”

“…In such cases, the attack of the allyl on the carbonyl group of the aldehyde is favored by the easy conversion of the allyl from η 3 to η 1 , which is easily observed by 1 H NMR spectroscopy. However, no indication of η 3 to η 1 - transformation of the allyl is observed for complexes 1a,b , even when treated with good donors such as pyridine …”

“…Compounds with Unsubstituted Allyl Ligands. The reaction of the η 3 -allyl acetonitrile dicarbonyl complexes 1a,b with DMAD in dichloromethane produces a solution which, after chromatography, yields tricarbonyl compounds 2a,b as orange oils.…”