The Reaction of Diethylzinc on Acetoxime

Menard, David F.; Aston, J. G.

doi:10.1021/ja01322a044

Cited by 8 publications

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“…The rate constants were 4.2X10-3 and 2.8 X sec-I respectively. With these facts in mind more accurate experiments were carried out a t the extremes hydroxyl cannot be accounted for by a bimolecular reaction of ethylzinc hydroxide with itself as in equation [4].…”

Section: Infrared Studiesmentioning

confidence: 99%

Mechanisms of the Reactions of Diethylzinc With Isopropanol and Water

Herold¹,

Aggarwal²,

Neff³

1963

Can. J. Chem.

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Reactions of diethyl~inc with isopropanol and water were studied by means of infrared absorption and gas evolution. The former method was found to be more reliable. Ethylzinc isopropoxide, formed from diethylzinc and isopropanol, was shown to be stable in the presence of excess isopropanol. The reaction of diethylzinc with water was found to proceed in a twostep manner, the product of the first being ethylzinc hydroxide. The decomposition of ethylzinc hydroxide was found to be first order with respect to itself and independent of diethylzinc.The reaction of zinc alkyls with compounds containing active hydrogens has been used in the past for qualitative and quantitative estimation of active hydrogen concentrations (1, 2). Generallj-, such procedures have been carried out with an excess of metal alkyl and little attention has been paid to the zinc-containing reaction products. Haurowitz noted that in 111any cases reaction of zinc alkjils with organic coinpouilds containing active hydrogens is not complete. Specifically in the case of benzyl alcohol only 60% of the expected ethane is evolved. Tolkatschev (3) and RIenard and Aston (4) In the studies reported herein, we have: (1) shown that ethylzinc isopropoxide formed from diethylzinc and isopropanol is stable in the presence of excess isopropanol in heptane solution; (2) shown that ethylzinc hydroxide is formed as an intermediate in the reaction of diethylzinc and water in ether solution; and (3) worked out the kinetics of the disappearance of ethylzinc hydroxide in the presence of various concentrations of diethylzinc in dimethoxyethane (glyn~e) solution. Two methods were used to study this latter reaction, namely, measurements of (1) the change in infrared absorption intensity a t 2.9 p (hydroxyl) and (2) ethane gas evolution as a function of time. However, these two methods give rate curves which are quite different. Since a lag in the evolution of ethane appeared to be the reason for this discrepancy, the kinetic a~lalj~sis was based on the infrared results. The initial portions of the gas evolution rate curves were nevertheless useful in obtaining an indication of the activation energy of the process. 'Presented at

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Section: Infrared Studiesmentioning

confidence: 99%

Mechanisms of the Reactions of Diethylzinc With Isopropanol and Water

Herold¹,

Aggarwal²,

Neff³

1963

Can. J. Chem.

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“…The synthesis of 1 − 9 was accomplished through examining derivations of one of the oldest known class of organometallic reactions: ethane elimination via reaction of diethyl zinc with various ratios of guanidine and alcohol . The reaction of 4 and 3 equiv of H-TMG with 3 equiv of diethyl zinc, (Et) 2 Zn, was performed.…”

Section: Introductionmentioning

confidence: 99%

“…The synthesis of 1-9 was accomplished through examining derivations of one of the oldest known class of organometallic reactions: ethane elimination via reaction of diethyl zinc with various ratios of guanidine and alcohol. 9 The reaction of 4 and 3 equiv of H-TMG with 3 equiv of diethyl zinc, (Et) 2 Zn, was performed. Products isolated from each reaction were found to be the novel trinuclear [Zn 3 (µ-TMG) 4 (Et) 2 ] (1) and [EtZn(µ-TMG)] 3 (2), respectively (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Structure, and Reactivity of Alkylzinc Complexes Stabilized with 1,1,3,3-Tetramethylguanidine

2007

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The synthesis and structural characterization of several novel alkylzinc guanidinate, alkoxide, and aryloxide complexes are reported. 1,1,3,3-Tetramethylguanidine, H-TMG, was successfully reacted with (Et)2Zn in a 4:3 and a 1:1 ratio to yield the corresponding linear [Zn3(μ-TMG)4(Et)2] (1) and cyclic [Zn(μ-TMG)(Et)]3 (2) complexes. Further investigations have shown 2 to react with alcohols, HOR, to form complexes with the general formula [Zn(Et)(OR)(H-TMG)] n , where OR = OCH2C(CH3)3 {ONep, n = 2 (3)}, OC6H3(CMe3)2-2,6 {DBP, n = 1 (4)}, and OC6H2Bu t 2-2,6-Me-4 {DBP-4-Me, n = 1 (5)}. The addition of (Et)2Zn to a solution of 4 yielded the unusual [Zn2(μ-TMG)(μ-DBP)(Et)2] (6). Complex 5 readily reacts with the alcohol, HOR‘, yielding dinuclear compounds with the formula [Zn(μ-OR‘)(DBP-4-Me)(H-TMG)]2, where OR‘ = OCH3 (OMe, 7) and OCH2CH3 (OEt, 8). Additionally, compound 4 was reacted with EtOH, yielding a complex with the formula [Zn(μ-OEt)(DBP)(H-TMG)]2 (9). The utility of compound 8 for use as a catalyst in the ring-opening polymerization of rac-lactide was additionally investigated. Compounds 1 − 9 were characterized by single-crystal X-ray diffraction. The bulk powders for all complexes were found to be in agreement with the crystal structures based on elemental analyses, FT-IR spectroscopy, and 1H and 13C NMR studies. The polymer was characterized by multi-nuclear NMR spectroscopy and MALDI-TOF mass spectrometry.

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“…On the basis of the above results, we propose the following nucleation and growth pathway (Figure ): the reaction of diethyl zinc with stearic acid in ODE leads to the formation of zinc stearate. , In fact, the synthesis of zinc stearate involves the reaction of a low reactivity zinc precursor (like ZnO or ZnS) with stearic acid at relatively low temperatures (160 °C). , In addition, it is well known from the literature that the reaction of zinc alkyls with compounds containing active hydrogens produces ethane. − Ethane forms by the reaction of hydrogen from stearic acid with the ethyl group from diethyl zinc. Ethane is then removed during the degassing procedure before injection into the microfluidic reactor.…”

Section: Resultsmentioning

confidence: 92%

Mechanistic Insights and Controlled Synthesis of Radioluminescent ZnSe Quantum Dots Using a Microfluidic Reactor

Guidelli

Lignos²,

Yoo³

et al. 2018

Chem. Mater.

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We describe the controlled colloidal synthesis and characterization of ZnSe quantum dots using a continuous-flow microfluidic reactor. A systematic investigation of the synthetic route reveals a possible two-stage pathway for ZnSe nanocrystal formation. The first stage corresponds to the formation of zinc selenide nuclei at low temperatures (160 °C), followed by the growth of ZnSe nanocrystals at higher temperatures (340 °C). The quantum dots exhibit sharp exciton absorption, with tunable emission spectra between 370 and 430 nm. The photoluminescence of ZnSe nanocrystals is characterized by narrow emission linewidths of 14–21 nm. For the first time, we report luminescent emission from ZnSe nanocrystals upon X-ray excitation, revealing that radioluminescence emission is associated to confined excitons, and that the radioluminescence intensity is a linear function of the fluence/dose rate of X-rays. The precise control of the synthesis of particles with uniform sizes and excellent optical properties associated with the microfluidic synthesis opens a new avenue for the controlled production of heavy-metal-free luminescent and radioluminescent nanocrystals in flow.

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The Reaction of Diethylzinc on Acetoxime

Cited by 8 publications

References 0 publications

Mechanisms of the Reactions of Diethylzinc With Isopropanol and Water

Mechanisms of the Reactions of Diethylzinc With Isopropanol and Water

Synthesis, Structure, and Reactivity of Alkylzinc Complexes Stabilized with 1,1,3,3-Tetramethylguanidine

Mechanistic Insights and Controlled Synthesis of Radioluminescent ZnSe Quantum Dots Using a Microfluidic Reactor

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