Observation of Linkage Isomerization in W(CO)₅(2,5-Dihydrofuran)

Abstract

UV photolysis of a cyclohexane solution of W(CO) 6 in the presence of 2,5-dihydrofuran (DHF) yields W(CO) 5 (η 1 (O)-DHF) with a bimolecular rate constant on the order of 10 7 L mol -1 s -1 . Time-resolved IR (TRIR) absorption spectroscopy is used to monitor the consequent intramolecular isomerization to W(CO) 5 (η 2 -(C,C)-DHF), which occurs with a rate constant on the order of 1-10 s -1 at 20-60 °C; activation parameters for the isomerization are determined to be ∆H q ) 17.3 ( 0.3 kcal/mol and ∆S q ) 0.9 ( 0.9 eu.

Ru(0)-Catalyzed C3-Selective Cross-Dimerization of 2,5-Dihydrofuran with Conjugated Dienes

“…There are arguments for the coordination mode of 2 to the transition-metal center. , Although we failed to get spectroscopic evidence for the intermediates in this catalysis, the most feasible coordination mode is a η 2 - C,C ′-2,5-dihydrofuran in the present reaction (intermediate A ). Though it is possible to postulate some rotamers of the 2,5-dihydrofuran fragment in intermediate A , only a single rotamer must be responsible for the oxidative coupling reaction, because we obtained the single diastereomers in the reactions using 3d , g , h .…”

Electron transfer triggered sulfoxide isomerization in ruthenium and osmium complexes

“…Time resolved IR spectroscopy reveals both a solvent dependent and solvent free pathway for CO displacement by the thioether on the picosecond to nanosecond timescale. Similarly, photolysis of M(CO) 6 (M = Cr, Mo, W) in the presence of excess 2,3-or 2,5-dihydrofuran (DHF) yields the O-bonded [M(CO) 5 (DHF)] [68][69][70]. This complex reverts intramolecularly to a 2 -DHF on a slow timescale (10 0 s −1 ).…”

Furans Bound Face‐On: Sequential Loss of CO in the Formation of [W(CO)4(η4‐2,5‐dimethylfuran)]

“…[12] Following their initial formation from [W(CO) 5 (CyH)], these complexes undergo an intramolecular linkage isomerization to yield [W(CO) 5 (h 2 -L)], in which the ligand is bound to the metal by means of its double bond. Although h 2 binding is normally seen in furan complexes, [3] this kind of linkage isomerization cannot account for the behavior of [W(CO) 5 (Me 2 Fur)], since the observed IR spectrum, which contains four C-O stretches, is inconsistent with a [W(CO) 5 L] structure.…”