Carbonyl halides of the Group VI transition metals. IX. Complexes with Bis(diphenylarsino)methane: Some further carbon monoxide carriers

1968 ◽  
Vol 21 (5) ◽  
pp. 1159 ◽  
Author(s):  
MW Anker ◽  
R Colton ◽  
IB Tomkins
Keyword(s):  
Carbon Monoxide ◽  
Transition Metals ◽  
Room Temperature ◽  
Bidentate Ligand ◽  
The Other ◽  
Group Vi ◽  
Mixed Coordination ◽  
Temperature And Pressure

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.

Carbony1 halides of the Group VI transition metals. XV. Complexes with Bis(1,2-diphenylphosphino)ethane

1969 ◽  
Vol 22 (7) ◽  
pp. 1341 ◽  
Author(s):  
MW Anker ◽  
R Colton ◽  
CJ Rix ◽  
IB Tomkins
Keyword(s):  
Carbon Monoxide ◽  
Transition Metals ◽  
Room Temperature ◽  
Conductivity Measurements ◽  
Group Vi ◽  
Complex Series ◽  
Reversible Reactions ◽  
New Type ◽  
Temperature And Pressure

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.

ARSENIDES OF THE TRANSITION METALS: II. THE NICKEL ARSENIDES

1957 ◽  
Vol 35 (10) ◽  
pp. 1205-1215 ◽  
Author(s):  
R. D. Heyding ◽  
L. D. Calvert
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Transition Metals ◽  
Stability Region ◽  
Room Temperature ◽  
Metastable Phase ◽  
The Other ◽  
Incongruent Melting ◽  
Diffraction Patterns ◽  
The Stability

Alloys of nickel and arsenic containing up to 60% As by weight have been studied by means of room temperature and high temperature Debye-Scherrer diagrams. Three compounds have been identified: Ni5As2, Ni12−xAs8 (maucherite), and NiAs (niccolite). The first of these is homogeneous from Ni5As2 to Ni4.8A2 at room temperature, and to Ni4.6As2 above 250 °C., while the latter is homogeneous from NiAs to Ni0.95As. Contrary to expectations the stability region of the compound Ni12−xAs8 is very narrow, and occurs at Ni11As8 rather than at Ni3As2. Evidence is presented in support of Hansen's contention that this compound has an incongruent melting point. Alloys in the region corresponding to Ni4.6As2 undergo two transitions below 200 °C, one of which is martensitic and produces a metastable phase, while the other is believed to result in the formation of a new compound, as yet unidentified. The diffraction patterns are discussed in some detail.

Carbonyl halides of the Group VI transition metals. XVI. Reactions of Bis(diphenylphosphino)methane with Diiodotetracarbonyltungsten(II)

1969 ◽  
Vol 22 (12) ◽  
pp. 2535 ◽  
Author(s):  
R Colton ◽  
CJ Rix
Keyword(s):  
Carbon Monoxide ◽  
Transition Metals ◽  
Molecular Species ◽  
Direct Interaction ◽  
Ionic Species ◽  
Reaction Scheme ◽  
Simple System ◽  
Tricarbonyl Complex ◽  
Group Vi ◽  
Unusual Type

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.

Carbonyl halides of the Group VI transition metals. XXIV. 1,2-Bis(diphenylarsino)ethane complexes of the molybdenum(II) halocarbonyls

1971 ◽  
Vol 24 (11) ◽  
pp. 2223 ◽  
Author(s):  
MW Anker ◽  
R Colton
Keyword(s):  
Carbon Monoxide ◽  
Transition Metals ◽  
Pure Form ◽  
Species Comparison ◽  
Electronic Effects ◽  
Group Vi ◽  
Dicarbonyl Compounds ◽  
Relative Stabilities ◽  
Dimeric Complexes ◽  
Self Consistent

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.

Carbonyl halides of the Group VI transition metals. V. Carbon monoxide carriers and some sulphur and nitrogen derivatives of molybdenum halocarbonyls

1968 ◽  
Vol 21 (1) ◽  
pp. 15 ◽  
Author(s):  
R Colton ◽  
GR Scollary ◽  
IB Tomkins
Keyword(s):  
Carbon Monoxide ◽  
Transition Metals ◽  
Direct Interaction ◽  
Group Vi ◽  
Derivatives Of

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.

Carbonyl halides of the Group VI transition metals. XIII. Diiodotetracarbonyls of molybdenum and tungsten and some of their derivatives

1969 ◽  
Vol 22 (2) ◽  
pp. 305 ◽  
Author(s):  
R Colton ◽  
CJ Rix
Keyword(s):  
Carbon Monoxide ◽  
Room Temperature ◽  
Direct Interaction ◽  
Radiation Reaction ◽  
Donor Ligands ◽  
Group Vi ◽  
Dicarbonyl Compound ◽  
Molybdenum Compound ◽  
First Time ◽  
And Tungsten

Diiodotetracarbonyls of molybdenum and tungsten(II) have been prepared for the first time by the direct interaction of the parent hexacarbonyls with iodine at room temperature under the influence of ultraviolet radiation. Reaction of the iodocarbonyls with donor ligands such as triphenylphosphine, triphenylarsine, and triphenylstibine generally gives neutral substitution products, but the reaction between the molybdenum compound and triphenylphosphine yielded the previously reported triphenylphosphonium salt of the triiodotricarbonyl(triphenylphosphine)-molybdate(II) ion. ��� Diiodotricarbonylbis(triphenylphosphine)tungsten(II) loses carbon monoxide on heating under vacuum to give the corresponding blue dicarbonyl compound. The dicarbonyl dissolved in dichloromethane readily absorbs carbon monoxide to reform the tricarbonyl and the compounds therefore represent a further carbon monoxide carrying system. ��

Carbonyl halides of the Group VI transition metals. XIX. Iodocarbonyl complexes of molybdenum and tungsten with Bis(diphenylarsino)methane

1970 ◽  
Vol 23 (3) ◽  
pp. 441 ◽  
Author(s):  
R Colton ◽  
CJ Rix
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Carbon Monoxide ◽  
Magnetic Resonance ◽  
Transition Metals ◽  
Direct Interaction ◽  
Acetone Solution ◽  
Group Vi ◽  
First Time ◽  
And Tungsten ◽  
Nuclear Magnetic

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.

Substituted carbonyl derivatives of the Group VI transition metals. IV. Reactions of some arene-metal tricarbonyls with Triaryl-phosphine and -arsine ligands

1973 ◽  
Vol 26 (3) ◽  
pp. 655 ◽  
Author(s):  
JA Bowden ◽  
R Colton ◽  
CJ Commons
Keyword(s):  
Carbon Monoxide ◽  
Solid State ◽  
Transition Metals ◽  
Steric Effects ◽  
Group Vi ◽  
Decomposition Products ◽  
Carbonyl Derivatives ◽  
Derivatives Of

The reactions of triphenylphosphine and triphenylarsine with (π- arene)M(CO)3 (M = Cr, Mo, W) to yield fac-M(CO)3(RPh3)3 (R = P, As) have been reexamined. Anomalies in the earlier literature have been resolved by the isolation of two solid state forms of each complex and by a study of the decomposition products of these compounds. Tricarbonyl complexes of tritolyl-phosphines and -arsines are also reported and their behaviour suggests steric effects initiate decomposition. In addition, a number of (π-arene)M(CO)3 compounds were shown to react with carbon monoxide to form M(CO)6.

ESEM - A multipurpose surface Electron Microscope

1986 ◽  
Vol 44 ◽  
pp. 632-633 ◽  
Author(s):  
G.D. Danilatos
Keyword(s):  
Electron Microscope ◽  
Room Temperature ◽  
Environmental Scanning ◽  
Gas Composition ◽  
Saturated Water Vapor ◽  
Surface Electron ◽  
Current State ◽  
Saturated Water ◽  
New Type ◽  
Temperature And Pressure

Over recent years a new type of electron microscope - the environmental scanning electron microscope (ESEM) - has been developed for the examination of specimen surfaces in the presence of gases. A detailed series of reports on the system has appeared elsewhere. A review summary of the current state and potential of the system is presented here.The gas composition, temperature and pressure can be varied in the specimen chamber of the ESEM. With air, the pressure can be up to one atmosphere (about 1000 mbar). Environments with fully saturated water vapor only at room temperature (20-30 mbar) can be easily maintained whilst liquid water or other solutions, together with uncoated specimens, can be imaged routinely during various applications.

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