Neutral, Anionic, and Paramagnetic 1,3,2-Diazaberyllacyles Derived from Reduced 1,4-Diazabutadienes

Albert Paparo; Stephen P. Best; K. Yuvaraj; Cameron Jones

doi:10.1021/acs.organomet.0c00017

Neutral, Anionic, and Paramagnetic 1,3,2-Diazaberyllacyles Derived from Reduced 1,4-Diazabutadienes

Albert Paparo, Stephen P. Best, K. Yuvaraj, Cameron Jones

School of Chemistry

Research output: Contribution to journal › Article › Research › peer-review

11 Citations (Scopus)

Abstract

A series of neutral, bulky diazabutadienediyl-substituted beryllacycles [Be(^DipDAB)(L)] (^DipDAB = [(DipNCH)₂]^2-, Dip = 2,6-diisopropylphenyl; L = OEt₂, THF,:C(RNCH)₂; R = Me (TMC), Prⁱ (IPriMe)) have been prepared and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The preparation of similar complexes bearing the smaller tert-butyl-substituted diazabutadienediyl ligand ([(Bu^tNCH)₂]^2-, viz. ^ButDAB) was attempted but gave rise to complex product mixtures, several components of which were isolated in trace yields. This phase of the study did, however, lead to the preparation of the homoleptic beryllium diradical complex [Be(^ButDAB^•)₂], which was characterized by X-ray crystallography and EPR spectroscopy. In efforts to access Be^I-Be^I-bonded dianions, [(^DipDAB)Be-Be(^DipDAB)]^2-, reductions of [Be(^DipDAB)(L)] were pursued, but these instead afforded largely intractable product mixtures. Treating ethereal solutions of [Be(^DipDAB)(OEt₂)] with lithium alkyls afforded highly reactive, heterocyclic beryllate salts, [Li(OEt₂)_2,1][Be(^DipDAB)R] (R = Me, Buⁿ). Subsequent treatment of [Li(OEt₂)][Be(^DipDAB)Buⁿ] with either N,N,N′,N′-tetramethylethylenediamine (tmeda) or N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (pmdeta) led to the formation of [Li(tmeda)₂][Be(^DipDAB)Buⁿ] and [Li(pmdeta)][Be(^DipDAB)Buⁿ]. Reactions between two of the heterocyclic beryllate salts and [BeX₂(OEt₂)₂] (X = Br, I) did not lead to clean salt metathesis reactions but gave mixtures of many products, several of which were isolated in very low yields. While the noninnocent nature of the diazabutadienediyl ligands of [Be(^DipDAB)(L)], and the [Be(^DipDAB)R]^- anions, hampered explorations of their further reactivity, these heterocycles hold promise as synthons for beryllium coordination chemistry.

Original language	English
Pages (from-to)	4208-4213
Number of pages	6
Journal	Organometallics
Volume	39
Issue number	23
DOIs	https://doi.org/10.1021/acs.organomet.0c00017
Publication status	Published - 14 Dec 2020

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10.1021/acs.organomet.0c00017

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@article{0b11e4536a094fb59fd10ff94df636f5,

title = "Neutral, Anionic, and Paramagnetic 1,3,2-Diazaberyllacyles Derived from Reduced 1,4-Diazabutadienes",

abstract = "A series of neutral, bulky diazabutadienediyl-substituted beryllacycles [Be(DipDAB)(L)] (DipDAB = [(DipNCH)2]2-, Dip = 2,6-diisopropylphenyl; L = OEt2, THF,:C(RNCH)2; R = Me (TMC), Pri (IPriMe)) have been prepared and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The preparation of similar complexes bearing the smaller tert-butyl-substituted diazabutadienediyl ligand ([(ButNCH)2]2-, viz. ButDAB) was attempted but gave rise to complex product mixtures, several components of which were isolated in trace yields. This phase of the study did, however, lead to the preparation of the homoleptic beryllium diradical complex [Be(ButDAB•)2], which was characterized by X-ray crystallography and EPR spectroscopy. In efforts to access BeI-BeI-bonded dianions, [(DipDAB)Be-Be(DipDAB)]2-, reductions of [Be(DipDAB)(L)] were pursued, but these instead afforded largely intractable product mixtures. Treating ethereal solutions of [Be(DipDAB)(OEt2)] with lithium alkyls afforded highly reactive, heterocyclic beryllate salts, [Li(OEt2)2,1][Be(DipDAB)R] (R = Me, Bun). Subsequent treatment of [Li(OEt2)][Be(DipDAB)Bun] with either N,N,N′,N′-tetramethylethylenediamine (tmeda) or N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (pmdeta) led to the formation of [Li(tmeda)2][Be(DipDAB)Bun] and [Li(pmdeta)][Be(DipDAB)Bun]. Reactions between two of the heterocyclic beryllate salts and [BeX2(OEt2)2] (X = Br, I) did not lead to clean salt metathesis reactions but gave mixtures of many products, several of which were isolated in very low yields. While the noninnocent nature of the diazabutadienediyl ligands of [Be(DipDAB)(L)], and the [Be(DipDAB)R]- anions, hampered explorations of their further reactivity, these heterocycles hold promise as synthons for beryllium coordination chemistry.",

author = "Albert Paparo and Best, {Stephen P.} and K. Yuvaraj and Cameron Jones",

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doi = "10.1021/acs.organomet.0c00017",

language = "English",

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T1 - Neutral, Anionic, and Paramagnetic 1,3,2-Diazaberyllacyles Derived from Reduced 1,4-Diazabutadienes

AU - Paparo, Albert

AU - Best, Stephen P.

AU - Yuvaraj, K.

AU - Jones, Cameron

PY - 2020/12/14

Y1 - 2020/12/14

N2 - A series of neutral, bulky diazabutadienediyl-substituted beryllacycles [Be(DipDAB)(L)] (DipDAB = [(DipNCH)2]2-, Dip = 2,6-diisopropylphenyl; L = OEt2, THF,:C(RNCH)2; R = Me (TMC), Pri (IPriMe)) have been prepared and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The preparation of similar complexes bearing the smaller tert-butyl-substituted diazabutadienediyl ligand ([(ButNCH)2]2-, viz. ButDAB) was attempted but gave rise to complex product mixtures, several components of which were isolated in trace yields. This phase of the study did, however, lead to the preparation of the homoleptic beryllium diradical complex [Be(ButDAB•)2], which was characterized by X-ray crystallography and EPR spectroscopy. In efforts to access BeI-BeI-bonded dianions, [(DipDAB)Be-Be(DipDAB)]2-, reductions of [Be(DipDAB)(L)] were pursued, but these instead afforded largely intractable product mixtures. Treating ethereal solutions of [Be(DipDAB)(OEt2)] with lithium alkyls afforded highly reactive, heterocyclic beryllate salts, [Li(OEt2)2,1][Be(DipDAB)R] (R = Me, Bun). Subsequent treatment of [Li(OEt2)][Be(DipDAB)Bun] with either N,N,N′,N′-tetramethylethylenediamine (tmeda) or N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (pmdeta) led to the formation of [Li(tmeda)2][Be(DipDAB)Bun] and [Li(pmdeta)][Be(DipDAB)Bun]. Reactions between two of the heterocyclic beryllate salts and [BeX2(OEt2)2] (X = Br, I) did not lead to clean salt metathesis reactions but gave mixtures of many products, several of which were isolated in very low yields. While the noninnocent nature of the diazabutadienediyl ligands of [Be(DipDAB)(L)], and the [Be(DipDAB)R]- anions, hampered explorations of their further reactivity, these heterocycles hold promise as synthons for beryllium coordination chemistry.

AB - A series of neutral, bulky diazabutadienediyl-substituted beryllacycles [Be(DipDAB)(L)] (DipDAB = [(DipNCH)2]2-, Dip = 2,6-diisopropylphenyl; L = OEt2, THF,:C(RNCH)2; R = Me (TMC), Pri (IPriMe)) have been prepared and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The preparation of similar complexes bearing the smaller tert-butyl-substituted diazabutadienediyl ligand ([(ButNCH)2]2-, viz. ButDAB) was attempted but gave rise to complex product mixtures, several components of which were isolated in trace yields. This phase of the study did, however, lead to the preparation of the homoleptic beryllium diradical complex [Be(ButDAB•)2], which was characterized by X-ray crystallography and EPR spectroscopy. In efforts to access BeI-BeI-bonded dianions, [(DipDAB)Be-Be(DipDAB)]2-, reductions of [Be(DipDAB)(L)] were pursued, but these instead afforded largely intractable product mixtures. Treating ethereal solutions of [Be(DipDAB)(OEt2)] with lithium alkyls afforded highly reactive, heterocyclic beryllate salts, [Li(OEt2)2,1][Be(DipDAB)R] (R = Me, Bun). Subsequent treatment of [Li(OEt2)][Be(DipDAB)Bun] with either N,N,N′,N′-tetramethylethylenediamine (tmeda) or N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (pmdeta) led to the formation of [Li(tmeda)2][Be(DipDAB)Bun] and [Li(pmdeta)][Be(DipDAB)Bun]. Reactions between two of the heterocyclic beryllate salts and [BeX2(OEt2)2] (X = Br, I) did not lead to clean salt metathesis reactions but gave mixtures of many products, several of which were isolated in very low yields. While the noninnocent nature of the diazabutadienediyl ligands of [Be(DipDAB)(L)], and the [Be(DipDAB)R]- anions, hampered explorations of their further reactivity, these heterocycles hold promise as synthons for beryllium coordination chemistry.

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U2 - 10.1021/acs.organomet.0c00017

DO - 10.1021/acs.organomet.0c00017

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VL - 39

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JO - Organometallics

JF - Organometallics

SN - 0276-7333

IS - 23

ER -

Neutral, Anionic, and Paramagnetic 1,3,2-Diazaberyllacyles Derived from Reduced 1,4-Diazabutadienes

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Neutral, Anionic, and Paramagnetic 1,3,2-Diazaberyllacyles Derived from Reduced 1,4-Diazabutadienes

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