Spinel Formation from Magnesium Aluminium Double Alkoxides

1986 ◽  
Vol 73 ◽  
Author(s):  
Kenneth Jones ◽  
Thomas J. Davies ◽  
Harold G. Emblem ◽  
Peter Parkes
Keyword(s):  
Nmr Spectroscopy ◽  
General Formula ◽  
Metal Atom ◽  
Vacuum Distillation ◽  
Viscosity Measurements ◽  
Spinel Formation ◽  
Bonding Phase ◽  
Xrd Studies ◽  
Aluminium Alkoxide

ABSTRACTDouble alkoxides of the general formula Mg[Al(OR)4]2 where R is iso-Pr or sec-Bu were prepared by reacting aluminium and magnesium metals together with the alcohol ROH and purified by vacuum distillation. They were characterised by IR, proton and 27Al NMR spectroscopy and MW determination. A magnesium aluminium double alkoxide was also prepared by treating the commercially available aluminium alkoxide ‘Aliso B’ [a mixed aluminium (iso-propoxide)(sec-butoxide)] with magnesium and iso-propanol. Treatment of magnesium aluminium double alkoxides with water and an alkanolamine (preferably triethanolamine) gives a rigid coherent gel. Viscosity measurements and 27Al NMR spectroscopy suggest that the double alkoxide does not break down to its constituents during hydrolysis. The air-dried gel was shown by XRD to convert quantitatively to spinel on firing to 1500°C. The resistance of the double alkoxide moiety to hydrolysis explains the ease of conversion to spinel on firing. The gel has been used to bind alumina and magnesia grain. Gels suitable for binding refractory grain were obtained only when the alkanolamine content corresponded to one alkanolamine group per metal atom. Electron micrographic and XRD studies showed that in fired refractory pieces, the bonding phase was spinel.

THE EFFECT OF FINE ALUMINA TYPE ON COMPOSITION OF IN SITU SPINEL FORMATION IN ALUMINA-MAGNESIA CASTABLES

2011 ◽  
Vol 25 (27) ◽  
pp. 3633-3639
Author(s):  
M. PAGHANDEH ◽  
A. MONSHI ◽  
R. EMADI
Keyword(s):  
Corrosion Resistance ◽  
Lattice Constants ◽  
Spinel Formation ◽  
Reactive Alumina ◽  
Xrd Studies

Three types of low cement castables (LCC) were prepared from 5% reactive alumina ( R 5), 5% calcined alumina ( A 5) and equal proportions of 2.5% (AR). The nest of the composition was fine bauxite (0–1 mm, 57%), coarse bauxite (1–3 mm, 20%), calcined magnesia (5%), secar 71 refractory cemet (7%) and microsilica (1%). By the addition of 5% water, castables were moulded, aged, dried and fired to 1400°C for 2 h. XRD studies showed higher amount of in situ spinel formation in A 5. The lattice constants of spinels in A 5, AR and R 5 were, respectively, 8.0348, 8.0688 and 8.0847 Å. This accounted for respectively alumina rich, stochiometry and magnesia rich spinels. Since calcined alumina is cheaper, produce higher amounts of spinel with the aid of alumina from the aggregate of bauxite and the binder of cement, and alumina rich spinel has better corrosion resistance properties, use of calcined alumina is recommended in LCC.

3,5-Dimethylpyrazolylphosphine molybdenum(0) and tungsten(0) carbonyl complexes

1980 ◽  
Vol 58 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Harry B. Davis ◽  
James K. Hoyano ◽  
Ping Yuen Leung ◽  
Louis K. Peterson ◽  
Brian Wolstenholme
Keyword(s):  
General Formula ◽  
Metal Atom ◽  
Phosphorus Atom ◽  
Phenyl Ring ◽  
Octahedral Geometry ◽  
Phosphine Ligand ◽  
Carbonyl Complexes ◽  
Coordination Sites ◽  
And Tungsten

Complexes with the general formula [LnM(CO)m], where [Formula: see text] x = 0–2, n = 1 or 2, M = Mo(0) or W(0), m = 3 or 4, were prepared by thermal or photolytic methods by the reaction of the appropriate 3,5-dimethylpyrazolyl phosphine ligand with M(CO)6, norbornadienemetaltetracarbonyl [C7H8M(CO)4], cycloheptatrienylmetaltricarbonyl [C7H8M(CO)3], [(Me2N(CH2)3NMe2)M(CO)4], [(CH3CN)2M(CO)4], or [(CH3CN)3M(CO)3]. Structural evidence indicates octahedral geometry about the metal atom centre, and several modes of coordination for the ligands in those complexes isolated and characterized. For x = 2, the ligand [Formula: see text] was monodentate, via phosphorus in [Formula: see text] and bidentate in [Formula: see text] where coordination by P and the 2N site of the pyrazolyl ring yielded four-membered [Formula: see text] metallocycles. For x = 1, the [Formula: see text] ligand was bidentate, via the phosphorus atom and one of the 2N sites of one of the pyrazolyl substituents, thus giving the four-membered [Formula: see text] metallocycle in [Formula: see text] and tridentate in [Formula: see text] where three facial CO's, two 2N atoms of the pyrazolyl rings, and a part of the phenyl ring occupy the six coordination sites. For x = 0, the P(Me2pz)3 ligand was tridentate via the 2N atoms of all three pyrazolyl rings, thus giving tricyclic systems [P(Me2pz)3M(CO)3] (VIII, IX).

Strukturuntersuchungen an Dihalogen(diphosphan)nickel-KompIexen in Lösung mit Differential-Puls-Polarographie / Structure Analysis of Dihalogeno(diphosphine)nickel Complexes in Solution with Differential Puls Polarography

1998 ◽  
Vol 53 (7) ◽  
pp. 694-698 ◽  
Author(s):  
Martin Mutz ◽  
Hans Peter Latscha
Keyword(s):  
Nmr Spectroscopy ◽  
General Formula ◽  
Structure Analysis ◽  
Nickel Complexes ◽  
H Nmr

Abstract The structures of twelve dihalogeno(diphosphine)nickel complexes of the general formula [NiX2(PR′2R′)2] (X = Cl, Br and I; R′ resp. R″ = -C2H5 or -C6H5) were analyzed in solution by differential puls polarography and 1H-NMR spectroscopy as a function of temperature.

Reactions of asymmetric carbodiimides with azoimide

1979 ◽  
Vol 44 (10) ◽  
pp. 2982-2986 ◽  
Author(s):  
Jan Světlík ◽  
Igor Hrušovský ◽  
Augustin Martvoň
Keyword(s):  
Nmr Spectroscopy ◽  
General Formula ◽  
H Nmr ◽  
Basic Nitrogen

Reaction of asymmetric aliphatic-aromatic and diaryl carbodiimides with HN3 leads to 1,5-disubstituted tetrazoles. Carbodiimides of general formula C6H5-N=C=N-R (R = alkyl) from an adduct at C=N bond exclusively at a less basic nitrogen, i.e. near phenyl whereas those with R = aryl afford a 1 : 1 mixture of products. 1H-NMR spectroscopy revealed an aminotetrazole-iminotetrazoline tautomerism of the prepared 1=phenyl-5-alkylaminotetrazoles, which undergo isomerization to 1-alkyl-5-anilinotetrazoles.

Reactions of the Divalent Tin Compounds R2M, R = N(SiMe3)2 or CH(SiMe3)2 with Complexes of the Platinum Group Metals

2003 ◽  
Vol 2003 (2) ◽  
pp. 101-104 ◽  
Author(s):  
Talal A.K. Al-Allaf
Keyword(s):  
Nmr Spectroscopy ◽  
General Formula ◽  
Elemental Analysis ◽  
Platinum Group Metals ◽  
Tin Compounds ◽  
Neutral Ligands ◽  
Platinum Group ◽  
Divalent Tin

The stannylenes R2Sn, (R = N(SiMe3)2 or CH(SiMe3)2) insert into M–X bonds of complexes [MX2L2] to give new complexes of the general formula [MX(SnR2X)L2], (M = Pt, Pd, Ni; X = Cl, N3, NO2; L = PEt3, PBu3, DPPE). They also insert into Pt–Cl bonds of the bridged complexes [{Pt(μ-Cl)Cl(L)}2], to give the new bridged complexes[{Pt(μ-Cl)(SnR2Cl)(L)}2], (R = N(SiMe3)2, L = PEt3, PBu3, PMe2Ph, PPh3), in which the bridge remained uncleaved. In one reaction of the stannylene R2Sn, where R = CH(SiMe3)2, the bridged complex [{Pt(μ-Cl)(SnR2Cl)(PEt3)}2] undergoes cleavage followed by migration of Cl to give [PtCl(SnR2Cl)(η2-SnR2)(PEt3)]. Further, the bridged complex [{Pt(μ-Cl)(SnR2Cl)(PEt3)}2], (R = N(SiMe3)2), with the neutral ligands L’, (L’ = PPh3, pyridine or AsPh3), undergoes bridge cleavage to form the complexes [PtCl(SnR2Cl)(PEt3)(L’)]. The reaction of the stannylene R2Sn, (R = N(SiMe3)2) with the platinum(0) complexes [Pt(C2H4)(PPh3)2] and [Pt(COD)2], COD = 1,5-cyclooctadiene is described. The complexes obtained have been characterised mainly by 31P NMR spectroscopy and elemental analysis.

Arene–manganese and arene–rhenium compounds of formula (arene)M(CO)2(SiCl3)

1997 ◽  
Vol 75 (5) ◽  
pp. 531-535 ◽  
Author(s):  
Valerie M. Hansen ◽  
Jonathan L. Male ◽  
Roland K. Pomeroy
Keyword(s):  
Nmr Spectroscopy ◽  
Metal Atom ◽  
Good Yield ◽  
Free Rotation ◽  
Nmr Spectrum ◽  
Manganese Compound ◽  
Restricted Rotation ◽  
H Nmr ◽  
Arene Ligand ◽  
Derivatives Of

Derivatives of formula (arene)M(CO)2(SiCl3) (M = Mn, Re) have been prepared in moderate to good yield by the reaction of M(CO)5(SiCl3) and the appropriate arene (with heptane in those cases where the arene was a solid) in an evacuated sealed tube at 230–260 °C for 12–24 h, depending on the arene and the metal. Carefully purified reagents were necessary to obtain satisfactory yields. The (η6-1,4-C6H4tBu2)M(CO)2(SiCl3) complexes in solution exhibit free rotation of the arene ring about the metal atom to −120 °C as ascertained by 1H NMR spectroscopy. The manganese compound did show the onset of decoalescence of two of the signals due to the arene ligand in the 13C{1H} NMR spectrum in CD2Cl2, solution below −90 °C. This, however, is interpreted in terms of restricted rotation of the tert-butyl substituent rather than restricted rotation of the arene ring. Keywords: arene, manganese, rhenium, restricted rotation.

Polyphosphate Chain Stability in Magnesia-Polyphosphate Cements

1991 ◽  
Vol 245 ◽  
Author(s):  
E. D. Dimotakis ◽  
W. G. Klemperer ◽  
J. F. Young
Keyword(s):  
Nmr Spectroscopy ◽  
Aqueous Solutions ◽  
General Formula ◽  
Chain Length ◽  
Amorphous Materials ◽  
Room Temperature ◽  
Degree Of Polymerization ◽  
Mas Nmr ◽  
Average Degree ◽  
Cement Pastes

ABSTRACTPolyphosphates of the general formula NanH2PnO3n+1·H2O, n = 6, 15, 70, where n is the average degree of polymerization, have been synthesized and characterized by 31P NMR and HPLC. Aqueous solutions of these polyphosphates react at room temperature with magnesia to form cement pastes that harden to amorphous materials. The compressive strengths and porosities obtained are similar to those of MgO-(NH4)H2P3O10-H2O cements. Although polyphosphate chain length does not have a significant effect on the strength of the cement, 31P MAS-NMR spectroscopy showed that the degree of polyphosphate chain degradation decreases as the average degree of polymerization, n, increases.

SYNTHESIS AND CHARACTERIZATION OF PLATINUM(II/IV) COMPLEXES WITH 2-AMINO-5-METHYL-4-PHENYLTHIAZOLE

2021 ◽  
Author(s):  
Danijela Lj. Stojković ◽  
◽  
Verica V. Jevtić ◽  
Đorđe S. Petrović ◽  
Sandra S. Jovičić Milić ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
General Formula ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Synthesis And Characterization ◽  
1H And 13C Nmr ◽  
Elemental Microanalysis

This paper examines the synthesis of two new complexes of platinum(II/IV) ion, general formula [PtL2]Cl2 and [PtL2]Cl4, where L is 2-amino-5-methyl-4-phenylthiazole. The structures of the above mentioned compounds were determined by elemental microanalysis, infrared, 1H and 13C NMR spectroscopy.

Solid state 13C-NMR spectroscopy and XRD studies of commercial and pyrolytic carbon blacks

Carbon ◽  
2000 ◽  
Vol 38 (9) ◽  
pp. 1279-1287 ◽  
Author(s):  
Hans Darmstadt ◽  
Christian Roy ◽  
Serge Kaliaguine ◽  
Guoying Xu ◽  
Michèle Auger ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Pyrolytic Carbon ◽  
13C Nmr Spectroscopy ◽  
Carbon Blacks ◽  
Xrd Studies ◽  
Solid State 13C Nmr

scholarly journals Spectroscopic properties and antimicrobial activity of dioxomolybdenum(VI) complexes with heterocyclic S,S’-ligands

2012 ◽  
Vol 77 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Sofija Sovilj ◽  
Dragana Mitic ◽  
Branko Drakulic ◽  
Marina Milenkovic
Keyword(s):  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Nmr Spectroscopy ◽  
Spectral Data ◽  
General Formula ◽  
Elemental Analysis ◽  
Spectroscopic Properties ◽  
Octahedral Geometry ◽  
Molecular Structures ◽  
Ir And Nmr Spectroscopy

Five new dioxomolybdenum(VI) complexes of the general formula[MoO2(Rdtc)2], 1-5, where Rdtc-refer to piperidine- (Pipdtc), 4-morpholine-(Morphdtc), 4-thiomorpholine-(Timdtc), piperazine- (Pzdtc) or Nmethylpiperazine- (N-Mepzdtc) dithiocarbamates, respectively, have been prepared. Elemental analysis, conductometric measurements, electronic, IR and NMR spectroscopy have been employed to characterize them. Complexes 1-5 contain a cis-MoO2 group and are of an octahedral geometry. Two dithiocarbamato ions join as bidentates with both the sulphur atoms to the molybdenum atom. The presence of different heteroatom in the piperidin? moiety influences the v(C----N) and v(C----S) vibrations, which decrease in the order of the complexes with: Pipdtc > N-Mepipdtc > Morphdtc > Pzdtc > Timdtc ligands. On the basis of spectral data, molecular structures of complexes 1-5 were optimized on semiempirical molecular-orbital level, and the geometries, as obtained from calculations, described. Antimicrobial activity was tested against nine different laboratory control strains of bacteria and two strains of yeast Candida albicans. All tested strains were sensitive. Complexes bearing heteroatom in position 4 of piperidine moiety are significantly more potent against bacteria tested comparing to corresponding ligands.

Sign in / Sign up

Export Citation Format

Share Document