Diethyl Ether Solution Research Articles

Rare examples of five-co-ordinate manganese(II) complexes containing monodentate ligands. Crystal structures of [MnBr2(PEt3)] and [Mnl2(PMeEt2)], and their reaction with dioxygen

The five-co-ordinate trigonal-bipyramidal complexes [MnBr2(PEt3)] and [Mnl2(PMeEt2)] have been prepared and their crystal structures determined. Both complexes contain polymeric (MnX2)n chains with a single phosphine co-ordinated at each trigonal-bipyramidal centre. The complexes absorb one mole of O2 per mole of complex in diethyl ether solution at –30 °C.

Electron paramagnetic resonance of the interaction of semiquinone, Na+ion pairs with phosphatidylcholine in ethereal solvents

The solubilization of sodium salts of 1,4-benzosemiquinone (BQ˙–), 1,4-naphthosemiquinone (NQ˙–), 2,3,5,6-tetramethylbenzosemiquinone (DQ˙–), 2-methyl-1,4-naphthosemiquinone (MNQ˙–), 2,6-di-tert-butyl-1,4-benzosemiquinone (DTBQ˙–) and 9,10-anthrasemiquinone (AQ˙–) in 1,2-dimethoxyethane (DME) and diethyl ether (DEE), in the presence and absence of egg yolk phosphatidylcholine (PC), under very dry conditions, has been studied utilizing electron paramagnetic resonance (EPR) spectroscopy. EPR spectra corresponding to both the ion pair and the ‘free’ ion species were observed simultaneously for NQ˙–, DQ˙– and MNQ˙– in the presence of small quantities of PC in DME. Weighted-average EPR spectra were observed for DTBQ˙– and AQ˙– in DME, evidenced by the monotonic variation of their corresponding g values or proton coupling constants as a function of added PC. Binding constants of the sodium semiquinone salts to PC were determined for both DME and DEE solutions. Binding constants of the solvated sodium–semiquinone ion pairs of PC were also determined for DME solutions. The roles of the solvent and PC in solvating the sodium–semiquinone ion pairs are strongly interrelated. Addition of methyl or tert-butyl groups and extension of the π cloud to both the BQ˙– and NQ˙– structures decreases the solvated sodium–semiquinone binding to PC in DME implying that solubilization occurs preferentially at the charged sites of the PC molecules.

Reaction of trialkylboranes with sodium diethyldihydroaluminate in the presence of 1,4-diazabicyclo[2.2.2]octane. a convenient, general method for preparation of sodium trialkylborohydrides

Trialkylboranes in tetrahydrofuran (THF) or diethyl ether (EE) solutions, including those with exceptionally large steric requirements, react readily with toluene solutions of sodium diethyldihydroaluminate in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) to yield the corresponding sodium trialkylborohydrides and diethylaluminum hydride. The diethylaluminum hydride precipitates from solution as its DABCO adduct, with the use of EE as solvent facilitating the separation. This reaction constitutes a convenient, general method for preparing sodium trialkylborohydrides.

Dalton communications. Synthesis and characterization of [Li(OEt2)3][Co2(SC6H2Pri 3-2,4,6)5]: a compound with a face-sharing ditetrahedral structure

The reaction of Li(SC6H2Pri3-2,4,6) with CoCl2 in diethyl ether solution affords [Li(OEt2)3][Co2(SC6H2Pri3-2,4,6)5] which features an anion that has a unique face-sharing structure composed of two CoS4 tetrahedra.

Behavior of Triphenylethylene Dianion in Diethyl Ether Solution

Abstract The temperature-dependent 13C NMR spectra have been observed for triphenylethylene dianion in diethyl ether. The analyses of spectral changes with temperatures reveal that the geminal phenyl rotations have differential rates and that the rotations are affected by rotational motion about the ethylenic Cα-Cα′ bond in the solution.

Tri- and tetra-meric copper(I) amides {Cu[N(SiMePh2)2]}3 and {Cu[N(SiMe2Ph)2]}4

The compounds {Cu[N(SiMePh2)2]}31 and {Cu[N(SiMe2Ph)2]}42 have been synthesised by the reaction of CuBr with the appropriate lithium silylamide in diethyl ether solution. Both were characterized by X-ray crystallography, 1H NMR and IR spectroscopy, and elemental analysis. They represent the first copper silylamides to be completely characterized by X-ray crystallography. Compound 1 has a very rare trimeric structure with the metals disposed in a triangular fashion and bridged by amide ligands. The less-crowded derivative 2 has an amide-bridged tetrameric structure and an almost square-planar arrangement of four coppers. The bridging amides are displaced from the Cu4 plane such that the Cu4N4 core possesses a butterfly structure. In 1 the Cu ⋯ Cu and Cu–N distances average 2.481(8) and 1.976(8)A and the corresponding distances in 2 are 2.69(3) and 1.936(6)A. Crystal data: 1, orthorhombic, space group Pbca, a= 29.421(8), b= 18.630(4), c= 29.971(8)A, Z= 8, R= 0.069 for 4239 [I > 3σ(I)] data; 2, triclinic, space group P, a= 15.365(3), b= 15.420(3), c= 17.797(3)A, α= 67.58(1), β= 64.28(1), γ= 66.95(1)°, Z= 2, R= 0.050 for 10 999 [I > 2σ(I)] data.

The reactions of bis(η-cyclopentadienyl)dihydridomolybdenum and -tungsten with diorganylmagnesium reagents

The compounds (C 5H 5) 2MH 2 (M  MO, W) do not react with (C 5H 5) 2Mg or (C 5Me 5) 2Mg. The reaction of (C 5H 5) 2MoH 2 with (CH 3) 2Mg in the presence of tmeda, (CH 3) 2NCH 2CH 2N(CH 3) 2, has been monitored by 1H NMR spectroscopy and yields Mg[Mo(H)(C 5H 5) 2) 2] 2(tmeda). A similar compound, Mg[Mo(H)(C 5H 5) 2] 2(Et 2O) 2, is formed from (C 5H 5) 2MoH 2 and (CH 3) 2Mg or [C 5H 5MgCH 3(Et 2O)] 2 in diethyl ether solution when no tmeda is present. These results are discussed in terms of ligand redistribution equilibria. (C 5H 5) 2WH 2 reacts too slowly with (CH 3) 2Mg for products to be isolated.

Tungsten(VI) complexes with bidentate coordination of the catecholate monoanion. Synthesis of [W(O)Cl 3(O,HOC 6H 4)·O(C 2H 5) 2] and synthesis and crystal structure of [W(O)Cl(O 2C 6H 4)(O,HOC 6H 4)·O(C 2H 5) 2

Monomeric tungsten complexes with catechol coordinated bidentately as the monoanion [1,2-O,OHC 6H 4] − have been prepared by reacting WOCl 4 with catechol in diethyl ether solution. One equivalent of catechol leads to the formation of [W(O)Cl 3(O, HOC 6H 4)·O(C 2H 5) 2], while two equivalents of catechol leads to the formation of [W(O)Cl(O 2C 6H 4)(O,HOC 6H 4)·O(C 2H 5)2], for which the crystal structure has been determined. In the complex the tungsten atom is octahedrally coordinated to one oxo ligand [ d(WO) = 1.65(2) Å], one chloro ligand [ d(WCl) = 2.325(7) Å] and one chelating catecholate dianion, [1,2-O 2C 6H 4] 2− [ d(WO) = 1.91(1) Å and 1.95(1) Å], in a plane almost perpendicular to the tungsten-oxo bond. A chelating catechol monoanion, [1,2-O,OHC 6H 4] −, with the negatively charged oxygen atom [ d(WO) = 1.89(1) Å] trans to a catecholate oxygen atom and the hydroxy oxygen atom trans to the oxo ligand [ d(WO) = 2.35(2) Å], completes the inner coordination sphere. A diethyl ether molecule is strongly hydrogen-bonded to the hydroxy group with a short distance of 2.51(2) Å between the ether oxygen atom and the hydroxy oxygen atom.

Determination of methylmercury in human blood using capillary gas chromatography and selected-ion monitoring

A capillary gas chromatographic method, using selected-ion monitoring in the electron-impact mode, was developed for the analysis of methylmercury (MeHg) in human blood. The samples, spiked with the internal standard propylmercury bromide (PropHgBr), were, after addition of sodium bromide and cupric sulfate, extracted with toluene. The organic phase was extracted with an ethanol—water solution of sodium thiosulfate. After addition of sodium bromide solution, the ethanol—water phase was extracted with toluene. Methylated derivatives (MeHgCH 2Br and PropHgCH 2Br) were formed by the addition of a diethyl ether solution of diazomethane. The chromatographic properties of the derivatives were much better than those of the non-methylated compounds. The m/z 215 fragment of MeHgCH 2Br and the molecular ion m/z 338 of PropHgCH 2Br were monitored. The calibration graphs, with a linear correlation coefficient of 0.992 ( n = 12) in the 1–5 μg/l concentration range, passed through the origin. The detection limit for MeHg in human blood was ca. 0.5 μg/l. Analysis of spiked blood samples at concentrations of about 2 and 10 μg/l gave a relative standard deviation of 4.2 and 5.5%, respectively ( n = 10).

13C, 6Li and 7Li NMR T1 and T1ρ study of ion‐pair dynamics and structure of lithium fluorenide

AbstractThe rate of interconversion between tight and loose ion pairs of lithium fluorenide in 2‐methyltetrahydrofuran was determined from 7Li relaxation in the rotating frame. The rate constant for the tight to loose ion‐pair interconversion at −60°C is 2.3 × 104 s−1 and for the reverse process 2.6 × 103 s−1. The 13C relaxation times (T1) of the fluorenyl anion, adjusted for viscosity changes, do not change significantly with the ion‐pair structure. The electric quadrupole relaxation contribution to the 7Li T1 was derived from 6Li and 7Li T1 measurements. Lower limits of 7Li quadrupole splitting constants (QSCs) were obtained from the 7Li quadrupolar and the 13C dipole‐dipole relaxation times. The QSC values are in the range 37–200 kHz and appear to reflect changes in the ion‐pair structure, with a low value corresponding to a solvent‐separated ion pair. The higher value for the contact ion pair is in agreement with a structure where the anion disrupts the symmetrical coordination of solvent molecules around the cation. A decreased QSC and a shortened 13C T1 at high temperature for the diethyl ether solution may be caused by aggregation.

Structural studies of organometallic compounds in solution: II. Magnesium bromide and iodide in diethyl ether and tetrahydrofuran; an extended X-ray absorption fine structure (EXAFS) and large angle X-ray scattering (LAXS) study

The structures of the magnesium iodide complexes formed in concentrated diethyl ether and tetrahydrofuran solutions have been determined by the large angle X-ray scattering (LAXS) technique. Those of the more dilute solutions of magnesium bromide in diethyl ether and tetrahydrofuran solutions have been determined by the extended X-ray absorption fine structure (EXAFS) method. The investigation of the MgI 2 diethyl ether solution was carried out at 44°C since this solution crystallizes at about 30°C. This solution is probably best considered a melt, the structure of which can be regarded as a close-packing of iodide ions with magnesium ions occupying some of the holes. The coordination around a specific magnesium ion depends on whether it occupies a tetrahedral or an octahedral hole. The average MgI bond distance is 2.75 Å. Solvated MgI + is the dominating complex in MgI 2tetrahydrofuran solution. Magnesium is probably six-coordinate in this complex, and the MgI bond distance is 2.52(5) Å. The MgBr bond distance is 2.49 and 2.66 Å in diethyl ether and tetrahydrofuran, respectively.

Structural studies of organometallic compounds in solution: IV. An extended X-ray absorption fine structure (EXAFS) and large angle X-ray scattering (LAXS) study of organomagnesium bromides in diethyl ether

Phenylmagnesium bromide in diethyl ether solution has been studied by large angle X-ray scattering (LAXS) and extended X-ray absorption fine structure, EXAFS, techniques. The reagent is present as both dimeric and monomeric complexes in this solvent, with magnesium octahedrally coordinated in both cases. The MgBr bond distance is 2.56(2) Å and the BrBr bond distance in the dimeric complex is 3.62(3) Å. The local structure around bromine in methyl- and ethyl-magnesium bromides has also been determined in diethyl ether solution by EXAFS. Data for the Br K edge were collected for solutions in the concentration range 0.1–1.0 M. For all the solutions the MgBr bond distance was found to be the same, 2.54 Å, within the limits of error. No other interaction was observed.

Structural studies of organometallic compounds in solution: III. A large angle scattering (LAXS) study of organomagnesium iodides in diethyl ether

Structures of methyl-, ethyl- and phenyl-magnesium iodides have been determined in diethyl ether solution by the large angle X-ray scattering (LAXS) technique. Solutions in the concentration range 0.9–2.7 M have been studied. The Grignard reagents are present as solvated monomeric and dimeric species. Magnesium coordinates an iodide ion, an alkyl or aryl group, and four diethyl ether molecules octahedrally in the monomeric complex. In the dimeric complex each magnesium is octahedrally coordinated by two bridging iodide ions, an alkyl or aryl group, and three solvent molecules. The distribution of monomeric and dimeric species in the different solutions is given by a dimerisation constant, K di = [(RMgX) 2][RMgX] −2, which is in the range 0.2–0.8 M −1. The MgI bond distance is between 2.74 and 2.81 Å.

The formation and reactions of some new functionally substituted derivatives of (η 5-cyclopentadienyl dicarbonylnitrosylchromium (cynichrodene)

The reaction between cynichrodenoic acid, (η 5-C 5H 4COOH)Cr(CO) 2NO ( 6) and phosphorus pentachloride produces cynichrodenoyl chloride ( II) in high yield. Subsequent reaction of 11 with sodium azide affords cynichrodenoyl azide ( 12), which undergoes Curtius rearrangement to form cynichrodenyl isocyanate ( 13). Subsequent hydrolysis of isocyanate 13 in aqueous KOH solution yields aminocyanichrodene ( 14). Azide 12 also undergoes Curtius rearrangement in the presence of benzyl alcohol to produce benzyl N-cynichrodenylcarbamate ( 15). Reactions of acid chloride 11 with ammonia, dimethylamine or aniline lead to the corresponding carboxamides ( 16–18). Amide 16 is readily dehydrated to produce cynichrodenecarbonitrile ( 19). Reactions of acid chloride 11 with either benzyl alcohol or hydroxymethylferrocene generate the corresponding esters ( 20–21), whereas treatment of a tetrahydrofuran solution of 11 with pyridine affords cynichrodenecarboxylic anhydride ( 22 in low yield. Reactions of acetylcynichrodene ( 2) with organolithium reagents, leading to both carbonyl addition and condensation products, have been investigated. Treatment of 2 with lithium diisopropylamide in diethyl ether solution produces the self-condensation product 1,3-dicynichrodenyl-but-2-en-1-one ( 24). Acetyl derivative 2 and benzaldehyde also undergo Claisen-Schmidt condensation in the presence of lithium diisopropylamide to afford cinnamoylcynichrodene ( 27).

Reduction of WCl 6 by allyltrimethylsilane. A convenient method to prepare WCl 5(OEt 2) and some other derivatives of WCl 5

WCl 6 was reacted with excess allyltrimethylsilane in diethyl ether solution at low temperature. The main product in the reaction was shown to be WCl 5(OEt 2) which was isolated as black—green air- and moisture-sensitive crystals. WCl 5(OEt 2) was reacted with different Lewis bases, e.g. pyridine and 9-fluorenone to yield the new compounds WCl 5 (pyridine) and WCl 5(9-fluorenone). The latter most likely being an oxygen bonded complex.

Reaction of 1-{(pentamethylcyclopentadienyl)(dicarbonyl)ferrio}-2-(2,4,6-tri-tert-butylphenyl)diphosphene with 1,2,4-triazoline-3,5-diones: formations and structures of the first 1,2-diaza-3,4-diphosphetidines and E,E-1,7-dioxa-4,5,10,11-tetraaza-3,4,8,9-tetraphosphacyclododeca-5,11-diene

Reaction of [(η5-C5Me5)(CO)2Fe–PP–MeS*]1(Mes*= 2,4,6-But3C6H2) with 1,2,4-triazoline-3,5-diones [[graphic omitted](O)]2(a: R = Ph; b: R = 4-EtOC6H4) in benzene at ambient temperature affords the first 1,2-diaza-3,4-diphosphetidines as part of the bicyclic compounds 4, whereas in diethyl ether solution the twelve-membered macrocycle 5 is obtained.

Synthesis and X-ray crystal structure of the rhenium(VII)tert-butylimido compound, [Re(NBut)2(η1-C5H5)]2(µ-C5H4)(µ-O)

The interaction of NaC5H5 in tetrahydrofuran with a diethyl ether solution of Re(NBut)3Cl gives rise to a compound [Re(NBut)2(η1-C5H5)]2(µ-C5H4)(µ-O) that has fluxional η1-C5H5 groups, non-equivalent ButN groups and a unique bridging C5H4 group; the structure has been elucidated by X-ray crystallography.

2H/1H Isotope Shifts for 6Li‐NMR: First Experimental Detection and Applications to Structural Problems in the Field of Organolithium Compounds

AbstractDeuterium‐induced isotope effects on 6Li chemical shifts, transmitted over two bonds, 2Δ(6Li)(2H/1H), have been measured for the first time for methyllithium and the system methyllithium/lithium iodide. The observed shifts are to low field and range from 15 to 20 ppb per CD3 group. The multiplicity and intensity distribution of the 6Li signals resulting for mixtures of CH3‐ and CD3‐containing samples in the limit of slow inter‐ as well as intra‐aggregate exchange yield information about the size of the various clusters present in diethylether solution. It is expected that these isotope shifts can facilitate structural investigations of organolithium compounds. In some cases, the results of such measurements are expected to be less ambiguous then the conclusions based on multiplets that arise from scalar 13C,6Li spin‐spin coupling.

Monomer-bound ion pairs in the stereoregular polymerization of propylene oxide by the Pruitt-Baggett catalyst

The Pruitt-Baggett adduct (PBA) ( MW = 438 g mol −1) that formed from the reaction of FeCl 3 with propylene oxide (PO) was hydrolysed in diethyl ether (ether) solutions at different r = H 2 O Fe molar ratios. The hydrolysates ( PBH r ), which were insoluble in ether, could be converted into catalytically active form ( PBC r ) by a thermal treatment. PBC r (r < 1) was soluble in etheric solvents and in pyridine. These solutions, in contrast to PBA and PBH r , were electrical conductors. Profound differences in the electrical conductivity of PBC r was observed by varying the hydrolysis ratio r. The observed conductivity decayed and finally vanished with a kinetically second-order process. This is explained by the free ions, formed from PBC 0.67 ( MW = 4400 g mol −1), being bound together with an ether (or PO) molecule to yield ether- (or PO-) bound ion pairs (PBCB). PBC 0.67 and the electrical conductivity of its freshly prepared solutions could be retrieved by ‘driving off’ (by drying under vacuum at 40°C) the ‘binding molecule’ (ether or PO) from PBCB. In contrast to this system, the electrical conductivity of solutions of PBC 0.20 (which shows inferior catalytic activity) did not change with ageing.

Synthesis and reactivity of dimethylindium derivatives: molecular and electronic structure of bis(μ-diethylamido)-tetramethyldi-indium(III)

Me 2InCl reacts with LiNEt 2 in diethyl ether solution to give the easily sublimable compound [Me 2InNEt 2] 2 whose UV photoelectron spectra are reported and discussed in combination with its molecular and crystal structure, in particular as regards the InN interactions within the dimeric molecule. Reactions of [Me 2InNEt 2] 2 with moderately acidic agents such as R 2PH lead to cleavage of the InNEt 2 bond and formation of Me 2InPR 2 (R = Et, C 6H 5).