Improved syntheses of [] and []: Structural characterization of Na[Cp∗MoO3]·5H2O and []

Abstract

Use of aqueous conditions and the ROOH (R = tBu or H) compounds as oxidizing agents affords a simple two-step, one-pot synthetic procedure leading to [Cp à 2 M 2 O 5 ] (M = Mo, W) from [M(CO) 6 ] selectively and in high yields. The hexacarbonyl compounds are converted to Na[Cp * M(CO) 3 ] in refluxing THF, then the mixture is diluted with water (W) or aqueous NaOH (Mo) and directly treated with 6 equiv. of ROOH. Acidification of an aqueous solution of the Na[Cp * MO 3 ] product affords spectroscopically pure [Cp à 2 M 2 O 5 ] in high isolated yields (global yields from [M(CO) 6 ], for R = tBu: Mo, 91%; W, 87%). The X-ray structures of Na[Cp * MoO 3 ] AE 5H 2 O and [Cp à 2 W 2 O 5 ] are also reported.

Rational, Facile Synthesis and Characterization of the Neutral Mixed‐Metal Organometallic Oxides Cp*2MoxW6–xO17 (Cp* = C5Me5, x = 0, 2, 4, 6)

“…Compounds Cp* 2 Mo 2 O 5 and Cp* 2 W 2 O 5 were synthesized according to the literature. [48] Water was deionized, and methanol (Carlo Erba, analytical grade) was used as received. Sodium tungstate dihydrate (Na 2 WO 4 ·2H 2 O) and sodium molybdate dihydrate (Na 2 MoO 4 ·2H 2 O) were purchased from Aldrich and used as received.…”

High oxidation state organomolybdenum and organotungsten chemistry in protic environments

“…In highly aqueous media, the compound self-ionizes to yield [Cp * MoO 2 (H 2 O)] + [Cp * MoO 3 ] − , whereas it maintains its neutral molecular form in organic solvents. Several X-ray diffraction studies of the molecular form have been published [81][82][83], and the structure of the trioxide anion (as the sodium salt) has also been recently reported [96]. A similar ionic dissociation was also demonstrated for the chlorido derivative, Scheme 8 [80].…”

“…compound [ 6 ] is shown in Scheme 5. A short-cut consisting of a three-step, one-pot procedure has recently been reported [96]. This involves the direct oxidation of Na[Cp * M(CO) 3 ], formed in a first step from [M(CO) 6 ] and NaCp * , with tBuOOH in water [96].…”

Aqueous Reduction of [Cp*2W2O5]: Characterization of the Triangular Clusters [Cp*3W3O4(OH)2]2+ and [Cp*3W3O6]+ – Comparison with Molybdenum

“…The starting compound, [Cp* 2 W 2 O 5 ], was prepared as described in the literature. [14] Synthesis 1, 6 mL). The mixture was acidified with CF 3 SO 3 H (10 drops) and stirred under an atmosphere of argon at r.t. for 3 d, during which time it changed from a yellow solution to a green suspension.…”

“…1 H NMR spectroscopic monitoring in MeOD/D 2 O reveals the formation of a single resonance (δ = 2.05 ppm) attributed to [Cp* WO 3 ] - [14] at neutral or basic pH, whereas several other products, yet to be identified, are obtained under strongly acidic conditions (pH 2: resonances at δ = 2.22, 2.19, 2.15).…”