30134-06-6Relevant academic research and scientific papers
Studies of distortional isomers: Spectroscopic evidence that green cis,mer-dichlorotris(dimethylphenylphosphine)oxomolybdenum(iv) is a mixture
Desrochers, Patrick J.,Nebesny, Kenneth W.,LaBarre, Michael J.,Lincoln, Sandra E.,Loehr, Thomas M.,Enemark, John H.
, p. 9193 - 9200 (1991)
The blue (1) and green (2) forms of cis,mer-MoOCl2(PMe2Ph)3 are not distortional isomers. An authentic sample of green 2 has been chromatographically and spectroscopically characterized to be a 65:35 mole fraction mixture of blue cis,mer-MoOCl2(PMe2Ph)3 and yellow mer-MoCl2(PMe2Ph)3 (yellow 3), respectively. Thin-layer chromatography separates green 2 into two individual peaks due to blue 1 and yellow 3. Elemental analysis of green 2 shows a significantly higher percent chlorine relative to blue 1, consistent with the presence of a 0.35 mole fraction of yellow 3 in green 2. Both infrared (500-150 cm-1) and Raman (1625-125 cm-1) spectra of green 2 have distinct features due to contributions from blue 1 and yellow 3. Furthermore, Raman spectra of blue 1 and green 2 indicate a ν(Mo=O) band at 944 ± 1 cm-1 that is conspicuously absent in the spectrum of yellow 3. The 500-MHz 1H NMR spectrum for green 2 shows several resonances characteristic of paramagnetic yellow 3 in the regions +7.5 to +11.5 ppm and -22 to -41 ppm. Visible spectroscopy implies that the color of green 2 is due to the summation of absorptions from blue 1 and yellow 3. X-ray photoelectron spectroscopy (XPS) of the Mo 3d regions resolves the contributions from the Mo(IV) (blue 1) and Mo(III) (yellow 3) species in green 2. Both the visible and XPS results confirm the 65:35 (blue1:yellow 3) molar composition of green 2. The facile cocrystallization of blue 1 and yellow 3 to give green 2 is likely driven by the increased entropy of the green 2 crystals, which decreases the free energy of crystallization. Similar compositional disorder processes are probably responsible for the anomalous bond lengths ascribed to distortional (bond stretch) isomerism in other series of inorganic complexes.
Bond-stretch isomerism in the complexes cis-mer-MoOCl2(PR3)3: A reinvestigation
Yoon, Keum,Parkin, Gerard,Rheingold, Arnold L.
, p. 2210 - 2218 (2007/10/02)
The molecular structures of a series of complexes ds-mer-MoOCl2(PR3)3 (PR3 = PMe3, PMe2Ph) have been investigated by X-ray diffraction methods. The data indicate a large range of apparent Mo=O bond lengths. The apparent lengthening of the Mo=O bond in these complexes is rationalized in terms of compositional disorder with the isostructural trichloride derivative mer-MoCl3(PR3)3. These results suggest that, contrary to the original suggestion (Chatt, J.; Manojlovic-Muir, L.; Muir, K. W. Chem. Commun. 1971, 655-656), there is no evidence for bond-stretch or distortional isomerism for the cis-mer-MoOCl2(PR3)3 system.
Oxo-molybdenum(IV) and -tungsten(IV) complexes with dithio acid ligands. Synthesis and structural investigation of MoO[S2C(PMe3)S-i-Pr-S,S′](S 2CS-i-Pr-S,S′,C)
Carmona, Ernesto,Galindo, Agustín,Guille-Photin, Christian,La?, Richard,Monge, Angeles,Ruiz, Caridad,Sánchez, Luis
, p. 488 - 492 (2008/10/08)
The title compound has been synthesized by the reaction of MoOCl2(PMe3)3 with the potassium salt of the isopropyl thioxanthate ligand, in the presence of CS2. The analogous reactions of the oxo complexes MOCl2(PMe3)3 (M = Mo, W) with this and other thioxanthate ligands -S2CSR (R = i-Pr, t-Bu) afford related products displaying similar IR spectral properties, but only for M = Mo and R = i-Pr have analytically pure crystals been isolated. The formation of the related dimethylphenylphosphine-xanthate complexes MO[S2C(PMe2Ph)O-i-Pr](S2CO-i-Pr) (M = Mo, W) is also reported. The molecular structure of MoO[S2C(PMe3)S-i-Pr](S2CS-i-Pr) has been determined by X-ray studies, which confirm that one of the thioxanthate ligands has suffered a nucleophilic attack of PMe3 on the carbon atom of the CS2 moiety, with formation of the zwitterionic ligand -S2C-(+PMe3)SR, S,S′-bonded to the molybdenum atom, while the other acts as an η3, S,S′,C ligand. The crystals are triclinic, P1, with unit cell constants a = 6.355 (3) A?, b = 12.252 (2) A?, c = 13.061 (2) A?, α = 92.96 (1)°, β = 93.65 (2)°, γ = 85.16 (3)°, and Dcalcd = 1.61 g cm-3 for Z = 2. The structure was refined to an R value of 0.032 by using 3488 independent observed reflections.
