scholarly journals Carbonyl halides of the Group VI transition metals. XXII. Reaction of Halopentacarbonyl-chromium, -molybdenum, and -tungsten(0) anions with carbon monoxide

1971 ◽  
Vol 24 (4) ◽  
pp. 881 ◽  
Author(s):  
JA Bowden ◽  
R Colton
1970 ◽  
Vol 23 (3) ◽  
pp. 441 ◽  
Author(s):  
R Colton ◽  
CJ Rix

Complexes of the general formulae M(CO)3(dam)I2, M(CO)3(dam)2I2, and M(CO)2(dam)2I2 have been prepared and characterized [M = Mo, W; dam = bis(diphenylarsino)methane]. All of the compounds are diamagnetic and non-electrolytes in acetone solution. The tungsten derivatives were prepared by direct interaction of dam with diiodotetracarbonyltungsten(11), but the molybdenum analogues were obtained by iodine oxidation of the zero-valent complex Mo(CO)4(dam)2 whose preparation is reported for the first time in this paper. The bis(dam)tricarbonyl complexes, M(C0)3(dam)2I2, are unstable in solution giving M(CO)2(dam)I2 and free dam in equilibrium with undissociated complex. The bis(dam)tricarbonyl complexes also readily lose carbon monoxide, especially in the case of molybdenum, to give M(CO)z(dam)2I2. These dicarbonyl complexes readily absorb carbon monoxide to re-form the tricarbonyl complexes to give a reversible carbon monoxide carrying system. Overall, these systems may be represented by the general equations : M(CO)3(dam)I2 + dam ↔ M(CO)3(dam)2I2 + CO These equilibria have been studied using both infrared and nuclear magnetic resonance techniques.


1968 ◽  
Vol 21 (6) ◽  
pp. 1435 ◽  
Author(s):  
R Colton ◽  
GR Scollary

Reaction of ammonium thiocyanate with dihalocarbonyls of molybdenum and tungsten(11) leads to the elimination of ammonium chloride and the formation of a dithiocyanatocarbonyl complex of the transition metal. Although the thiocyanatocarbonyls themselves have not been isolated in a pure state, a number of substituted derivatives with phosphorus donor ligands have been prepared and characterized. In general these complexes are less stable than the corresponding carbonyl halide derivatives.


1969 ◽  
Vol 22 (7) ◽  
pp. 1341 ◽  
Author(s):  
MW Anker ◽  
R Colton ◽  
CJ Rix ◽  
IB Tomkins

Compounds of the general formulae M(CO)3(dpe)X2, [M(CO)2(dpe)1.5X2]2, and M(CO)2(dpe)2X2 have been prepared and characterized (M = Mo, W; dpe = bis- (1,2-diphenylphosphino)ethane; X = Cl, Br, I). All of the compounds are diamagnetic and most of them are non-electrolytes. However, conductivity measurements indicate that, for the iodo derivatives only, the bis(dpe) compounds should be formulated as 1 : 1 electrolytes, [M(CO)2(dpe)2I]I. ��� For the iodo series of compounds only, there is a complex series of reversible reactions including a new type of carbon monoxide carrying system. In addition, the dimeric dpe derivatives are cleaved by carbon monoxide at room temperature and pressure to give equal quantities of [M(CO)2(dpe)2I]I and M(CO)3(dpe)I2.


1968 ◽  
Vol 21 (11) ◽  
pp. 2657 ◽  
Author(s):  
JA Bowden ◽  
R Colton

Dibromotetracarbonylmolybdenum, Mo(CO)4Br2, and the dihalotetracarbonyltungsten compounds, W(CO)4X2 (where X = Cl, Br), have been isolated and characterized. These highly reactive compounds are all diamagnetic. The trihalotetracarbonyl anions [M(CO)4X3]- (M = Mo, W) have been isolated as their tetraethylammonium salts from the parent halocarbonyls. These yellow diamagnetic compounds are the first tetracarbonyl derivatives to be prepared from the parent halocarbonyls.


1968 ◽  
Vol 21 (5) ◽  
pp. 1159 ◽  
Author(s):  
MW Anker ◽  
R Colton ◽  
IB Tomkins

Complexes of the types MX2(CO)3(dam)2 and MX2(CO)2(dam)2 [M = Mo, W; X = Cl, Br; dam = bis(diphenylarsino)methane] have been prepared and characterized. The compounds are all non-electrolytes; in the tricarbonyls both of the potentially bidentate arsenic ligands are in fact acting only as monodentates, but in the dicarbonyls there is mixed coordination with one ligand monodentate and the other bidentate. The dicarbonyl complexes absorb carbon monoxide in solution at room temperature and pressure, a metal-arsenic bond of the bidentate ligand is broken, and the corresponding tricarbonyl compound is produced. The reaction is readily reversible; thus the system is an example of a carbon monoxide carrier.


1969 ◽  
Vol 22 (12) ◽  
pp. 2535 ◽  
Author(s):  
R Colton ◽  
CJ Rix

Compounds of the general formulae W(CO)3dpmI2 and W(CO)2(dpm)2I2 [dpm = bis(diphenylphosphino)methane] have been prepared by direct interaction of the ligand with diiodotetracarbonyltungsten(II). However, this apparently simple system is complicated by the existence of two isomers of the tricarbonyl complex and three isomeric forms of the dicarbonyl. The various isomers have been separated and characterized individually and the interconversions between all the complexes have been investigated. The overall reaction scheme contains a partial carbon monoxide carrying system and an example of an unusual type of isomerism: �������������������� W(CO)2(dpm)2I2 → [W(CO)2(dpm)2I]I that is, isomerism of a molecular species to an ionic species.


1971 ◽  
Vol 24 (11) ◽  
pp. 2223 ◽  
Author(s):  
MW Anker ◽  
R Colton

Complexes of the general formulae Mo(CO)3(dae)X2 and [Mo(CO)2(dae)1.5X2]2 [X = Cl, Br, I; dae = 1,2-bis(diphenylarsino)ethane] have been prepared and characterized. The chloro- and bromo-tricarbonyl species exist in two isomeric forms. All of the dae-bridged dimeric complexes can be cleaved by carbon monoxide, to reform the corresponding tricarbonyl, and by excess dae to give soluble dicarbonyl compounds which are thought to be of the type Mo(CO)2(dae)2X2. Unfortunately, the equilibria �������������� [Mo(CO)2(dae)1.5X2]2+dae ↔ 2Mo(CO)2(dae)2X2 are very labile, and all attempts to isolate the bis(dae) complexes in a pure form resulted in the precipitation of the sparingly soluble dimeric species. ��� Comparison of the complexes derived from the halocarbonyls with dae and other ditertiary phosphines and arsines shows that, as the halogen is varied, the changes in the relative stabilities of the complexes obtained within each ligand series are all explicable on the basis of a self-consistent steric argument, but comparison of the complexes of dae and its diphosphine analogue, dpe, suggests that electronic effects become significant on changing from arsenic to phosphorus donor atoms.


1968 ◽  
Vol 21 (1) ◽  
pp. 15 ◽  
Author(s):  
R Colton ◽  
GR Scollary ◽  
IB Tomkins

The blue compounds MX2(CO)2(Ph3P)2 (M = Mo and W, X = Cl and Br) have been shown to absorb carbon monoxide very readily indeed to form the corresponding tricarbonyls, and as reported earlier, the tricarbonyls may be easily converted into the dicarbonyls. The dicarbonyl is therefore a carbon monoxide carrier. The compounds Mo(CO)3 dtc2 and Mo(CO)2 dtc2 (dtc = diethyldithiocarbamate) also represent a carbon monoxide carrying system, but in this case both compounds are rather unstable. The compounds MoX2(CO)2 btp2 (btp = N-n-butylthiopicolinamide; X = Cl, Br) have been prepared by direct interaction of the ligand and the appropriate halocarbonyl. Although these compounds are believed to be monomeric they do not absorb carbon monoxide.


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