Carbonyl halides of the Group VI transition metals. XIV. Substitution derivatives of the trihalotetracarbonylmolybdenum(II) anions

1969 ◽  
Vol 22 (5) ◽  
pp. 905 ◽  
Author(s):  
JA Bowden ◽  
R Colton
Keyword(s):  
Transition Metals ◽  
Ammonium Salts ◽  
Group Vi ◽  
Complete Series ◽  
First Time ◽  
Derivatives Of

The complete series of substituted halocarbonyl anions [Mo(CO)3RPh3X3]- (where R is P, Sb, As; X is Cl, Br) have been characterized as their tetraethyl-ammonium salts. Each substituted anion has been prepared by two distinct methods and all of the compounds can exist as two isomers. Except for the α-isomer of [Mo(CO)3PPh3Br3]- these complexes are reported for the first time.

Carbonyl halides of the Group VI transition metals. XI. Dithiocyanatocarbonyl derivatives of molybdenum and tungsten(II)

1968 ◽  
Vol 21 (6) ◽  
pp. 1435 ◽  
Author(s):  
R Colton ◽  
GR Scollary
Keyword(s):  
Transition Metal ◽  
Transition Metals ◽  
Ammonium Chloride ◽  
Pure State ◽  
Ammonium Thiocyanate ◽  
Donor Ligands ◽  
Group Vi ◽  
Derivatives Of ◽  
And Tungsten

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.

scholarly journals Synthetic Derivatives of Natural Alkaloid Harmine

2016 ◽  
Vol 11 (3) ◽  
pp. 199
Author(s):  
N.M. Ismagulova ◽  
Zh.S. Nurmaganbetov ◽  
A.Zh. Turmukhambetov ◽  
T.S. Seitembetov ◽  
S.M. Adekenov
Keyword(s):  
Indole Alkaloid ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Peganum Harmala ◽  
Underground Part ◽  
X Ray ◽  
Natural Alkaloid ◽  
First Time ◽  
Synthetic Derivatives ◽  
Derivatives Of

The indole alkaloid harmine was extracted from underground part of <em>Peganum harmala L.</em> With the purpose of obtaining the new biological active derivatives on base of alkaloid harmine the chemical modification was carried out. The p-toluolsulfochlorid, p-toluolsulfoacid, hydrochloric, sulfuric, nitric acids, dioxide selenium and phthalic anhydride have been chosen as modifiers. For the first time quaternary ammonium salts, derivatives of N-oxide and N (2)-oxyharminiumphthalate harmine are synthesized. The structure of the synthesized compounds is determined by methods of the spectral analysis and X-ray analysis. Antimicrobic and phagocytosis stimulating activities of isolated alkaloids and their derivatives are investigated.

Carbonyl halides of the Group VI transition metals. VIII. Paramagnetic and diamagnetic dicarbonyl derivatives of molybdenum(II)

1968 ◽  
Vol 21 (5) ◽  
pp. 1155 ◽  
Author(s):  
R Colton ◽  
CJ Rix
Keyword(s):  
Electron Spin Resonance ◽  
Transition Metals ◽  
General Formula ◽  
Electron Spin ◽  
Group Vi ◽  
Spin Resonance ◽  
Derivatives Of

Complexes of the general formula Mo(CO)2L2X2 (L = pyridine (py), 2,2'- dipyridyl (dipy), 1,l0-phenanthroline (phen); X = Cl, Br) have been isolated. The pyrldine derivatives are yellow monomeric compounds which are paramagnetic, but the complexes with dipy and phen contain diamagnetic seven-coordinate cations and are correctly formulated as [Mo(CO)2L2X]+X-. Conductance, infrared, magnetic, and electron spin resonance studies have been carried out.

Substituted carbonyl derivatives of the Group VI transition metals. I. Complexes with Bis(diphenylarsino)methane

1971 ◽  
Vol 24 (12) ◽  
pp. 2461 ◽  
Author(s):  
R Colton ◽  
CJ Rix
Keyword(s):  
Transition Metals ◽  
X Ray Diffraction ◽  
Monodentate Ligand ◽  
Group Vi ◽  
X Ray ◽  
Carbonyl Derivatives ◽  
Physical Measurements ◽  
Novel Structure ◽  
Derivatives Of ◽  
Mode Of Coordination

The reactions of the potentially bidentate ditertiary arsine ligand bis-(diphenylarsino)methane, dam, with the hexacarbonyls of the Group VI transition metals have been investigated. N.m.r, spectroscopy has been used to determine the mode of coordination of the ligand. In the compounds M(CO)5(dam), M(CO)4(dam)2, and M(CO)3(dam)3 [M = Cr, Mo, W], dam is acting as a monodentate ligand, but in M(CO)4(dam) it is acting as a normal chelate coordinating to the metal through both arsenic atoms. In the cases of molybdenum and chromium, only, a further type of complex M(CO)2(dam) has been isolated. The results of N.M.R., infrared, and mass spectrometry, together with other physical measurements, can only be explained on the assumption that the ligand was coordinated to the metal by an arene π-linkage and by one arsenic atom. This novel structure has been confirmed by a single crystal X-ray diffraction study on the chromium compound.

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. VII. Nitrosyl halide derivatives of molybdenum and tungsten(II)

1968 ◽  
Vol 21 (5) ◽  
pp. 1149 ◽  
Author(s):  
MW Anker ◽  
R Colton ◽  
IB Tomkins
Keyword(s):  
Nitric Oxide ◽  
Transition Metals ◽  
New Method ◽  
Natural Explanation ◽  
Group Vi ◽  
New Feature ◽  
Derivatives Of ◽  
And Tungsten

The previously reported dihalodinitrosylbis(triphenylphosphine)molybdenum and tungsten(11) type complexes, M(NO)2L2X2 (M = Mo, W; L = PPh3, AsPh3, SbPh3; X = Cl, Br), have been prepared by a new method involving the action of nitric oxide on the corresponding tricarbonyl derivatives. The new feature of this method is that, unlike the previous methods, it is not stereospecific, and in some cases all three possible cis isomers are formed. The identification of the various isomers has given a natural explanation of the apparently anomalous order of π-bonding effects in these complexes previously reported by Cotton and Johnson.

scholarly journals Carbonyl halides of the Group VI transition metals. II. Derivatives of molybdenum tetracarbonyl dibromide

1966 ◽  
Vol 19 (8) ◽  
pp. 1519 ◽  
Author(s):  
R Colton ◽  
IB Tomkins
Keyword(s):  
Transition Metals ◽  
Group Vi ◽  
Derivatives Of

Carbonyl halides of the Group VI transition metals. XVIII. Bis(diphenylphosphino)methane derivatives of iodocarbonyls of molybdenum

1970 ◽  
Vol 23 (2) ◽  
pp. 223 ◽  
Author(s):  
R Colton ◽  
JJ Howard
Keyword(s):  
Transition Metals ◽  
Isomeric Form ◽  
Group Vi ◽  
New Type ◽  
Derivatives Of

Bis(diphenylphosphino)methane, dpm, reacts with hexacarbonylmolybdenum to give Mo(CO)4 dpm and subsequently trans-Mo(CO)2(dpm)2. Oxidation of the tetracarbonyl derivative with iodine yielded Mo(CO)3(dpm)I2; reaction of this complex with further dpm gave Mo(CO)2(dpm)2I2. As with the corresponding tungsten system there are two isomers of Mo(CO)2(dpm)2I2 and three isomeric forms of Mo(CO)2(dpm)2I2 which can be obtained by this method of synthesis, all of which have been isolated and characterized individually. trans- Mo(CO)2(dpm)2 reacts with iodine to give a fourth isomeric form of the iododicarbonyl complex, trans- [Mo(CO)2(dpm)2]I2 which is a new type of halocarbonyl complex of molybdenum(11).

scholarly journals Base-free enantioselective SN2 alkylation of 2-oxindoles via bifunctional phase-transfer catalysis

2021 ◽  
Vol 17 ◽  
pp. 2287-2294
Author(s):  
Mili Litvajova ◽  
Emiliano Sorrentino ◽  
Brendan Twamley ◽  
Stephen J Connon
Keyword(s):  
Hydrogen Bond ◽  
Ad Hoc ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
Quaternary Ammonium Salts ◽  
Enantioselective Synthesis ◽  
Ammonium Salts ◽  
Synthetic Utility ◽  
First Time ◽  
Derivatives Of

N-Protected oxindole derivatives of unprecedented malleability bearing ester moieties at C-3 have been shown to participate in enantioselective phase-transfer-catalysed alkylations promoted by ad-hoc designed quaternary ammonium salts derived from quinine bearing hydrogen-bond donating substituents. For the first time in such phase-transfer-catalysed enolate alkylations, the reactions were carried out under base-free conditions. It was found that urea-based catalysts outperformed squaramide derivatives, and that the installation of a chlorine atom adjacent to the catalyst’s quinoline moiety aided in avoiding selectivity-reducing complications related to the production of HBr in these processes. The influence of steric and electronic factors from both the perspective of the nucleophile and electrophile were investigated and levels of enantiocontrol up to 90% ee obtained. The synthetic utility of the methodology was demonstrated via the concise enantioselective synthesis of a potent CRTH2 receptor antagonist.

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