A new isomer of molybdenum(IV) chloride

Improved Preparations of Molybdenum Coordination Compounds from Tetrachlorobis(diethyl ether)molybdenum(IV)

“…Heating the isolated [MoCl 4 (OEt 2 ) 2 ] solid under vacuum leads to the complete loss of the ether ligands at a relatively low temperature, leaving amorphous (by X-ray powder diffraction) MoCl 4 . [24] The observed magnetic moment of 1.6 µ B for our amorphous MoCl 4 does not compare with any of those reported for the three crystalline phases (i.e. Samples of ether-free MoCl 4 have been obtained by operating at temperatures up to 130°C.…”

“…Darkening of the solid already occurs at about 55°C, while at 80°C the powder is totally black. 0.85 µ B for α-MoCl 4 , [21] 2.31Ϫ2.54 µ B for β-MoCl 4 , [22] and 1.91 µ B for γ-MoCl 4 [24] ), although it is closest to that of the γ phase. This procedure is considerably more practical and time efficient than the literature preparations (see below) and leads to a more chemically reactive material.…”

“…Samples of ether-free MoCl 4 have been obtained by operating at temperatures up to 130°C. [24] On the other hand, the γ phase was shown to transform at ca. Scheme 2 Three different crystalline forms of MoCl 4 have been described in the literature, namely α-MoCl 4 , [21] β-MoCl 4 , [22,23] and γ-MoCl 4 .…”

Improved Preparations of Molybdenum Coordination Compounds from Tetrachlorobis(diethyl ether)molybdenum(IV)

“…Three different crystalline forms of MoCl 4 have been described in the literature, namely α‐MoCl 4 ,21 β‐MoCl 4 ,22,23 and γ‐MoCl 4 24. The α form was obtained from MoCl 5 by reflux with tetrachloroethylene in carbon tetrachloride; a reflux time shorter than two days is said to leave unchanged pentachloride 21.…”

“…The α form was obtained from MoCl 5 by reflux with tetrachloroethylene in carbon tetrachloride; a reflux time shorter than two days is said to leave unchanged pentachloride 21. The β form was obtained by comproportionation of MoCl 5 and MoCl 3 in a temperature gradient,22 while the γ form was prepared by heating a mixture of MoO 2 and carbon with a nitrogen stream saturated with CCl 4 vapors 24. The observed magnetic moment of 1.6 µ B for our amorphous MoCl 4 does not compare with any of those reported for the three crystalline phases (i.e.…”