Synthesis and Structural Diversity of Barium (<i>N</i>,<i>N</i>-Dimethylamino)diboranates

Daly, Scott R.; Bellott, Brian J.; Nesbit, Mark A.; Girolami, Gregory S.

doi:10.1021/ic2016879

Cited by 19 publications

(42 citation statements)

References 79 publications

(119 reference statements)

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“…The chemical shifts of δ 2.09 and 2.10 for the NMe 2 protons in 1 and 7 in d 6 -DMSO, respectively, agree with those measured for other DMADB compounds in the same solvent: δ 2.09 for Ba(DMADB) 2 (tmeda) 41 and δ 2.10 for [Ba(15-crown-5) 2 ]-[DMADB] 2 . 41 In contrast, in d 6 -benzene the chemical shifts of the NMe 2 resonances of 3−6 all lie between δ 2.50 and 2.64, or about 0.5 ppm downfield of the shifts seen in d 6 -DMSO.…”

Section: ■ Results and Discussionsupporting

confidence: 81%

“…The pattern of bands in the IR spectrum of the 12-crown-4 complex 7 is rather different from that seen in the spectra of the other Sr compounds, as might be expected from the presence of a noncoordinating DMADB anion in 7 but not in the other compounds. The highest frequency bands seen for 7 at 2345 and 2338 cm −1 agree with the expectation that the terminal B−H stretches of noncoordinated DMADB ions should be red-shifted in comparison to the terminal B−H stretches of covalently bound DMADB molecules; 41 The 1 H and 11 B NMR spectra of 1−7 are generally similar to those observed for analogous calcium 39 and barium 41 compounds. The spectra of 1 and 7 were acquired in d 6 -DMSO due to the low solubilities of these compounds in noncoordinating solvents, whereas the NMR spectra of 3−6 were acquired in d 6 -benzene.…”

Section: ■ Results and Discussionsupporting

confidence: 74%

“…For all four compounds the 1 H NMR line shape of the BH 3 groups is a 1:1:1:1 quartet with a 1 J BH coupling constant to the 11 B nucleus (I = 3/2) of between 90 and 92 Hz. It is difficult to compare these shifts with those of other divalent metal DMADB compounds 39,41,44,45 due to the large influence of the nature of the metal center on the chemical shift.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…40 In contrast, Ba(H 3 BNMe 2 BH 3 ) 2 and its adducts did not show any appreciable volatility up to 200 °C at 10 −2 Torr. 41 Here we report the synthesis and characterization of strontium compounds bearing the N,N-dimethylaminodiboranate anion. As we will show, several of these compounds can be sublimed with high yields under relatively mild conditions and thus are potentially useful as precursors for the CVD of strontiumcontaining thin films.…”

Section: ■ Introductionmentioning

confidence: 99%

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Synthesis and Characterization of Strontium N,N-Dimethylaminodiboranates as Possible Chemical Vapor Deposition Precursors

Dunbar

Girolami

2020

Inorg. Chem.

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The reaction of SrBr 2 with 2 equiv of sodium N,N-dimethylaminodiboranate (DMADB; Na(H 3 BNMe 2 BH 3 )) in Et 2 O at 0 °C followed by crystallization and drying under vacuum gives the unsolvated strontium compound Sr(H 3 BNMe 2 BH 3 ) 2 (1). Before the vacuumdrying step, the colorless crystals obtained by crystallization consist of the diethyl ether adduct Sr(H 3 BNMe 2 BH 3 ) 2 (Et 2 O) 2 (2). If the reaction of SrBr 2 with 2 equiv of Na(H 3 BNMe 2 BH 3 ) is carried out in the more strongly coordinating solvent thf, the solvate Sr(H 3 BNMe 2 BH 3 ) 2 (thf) 3 (3) is obtained. Treating the thf adduct 3 with 1,2-dimethoxyethane (dme), bis(2-methoxyethyl) ether (diglyme), or N,N,N′,N′-tetramethylethylenediamine (tmeda) in thf affords the new compounds Sr(H 3 BNMe 2 BH 3 ) 2 (dme) 2 (4), Sr(H 3 BNMe 2 BH 3 ) 2 (diglyme) (5), and Sr(H 3 BNMe 2 BH 3 ) 2 (tmeda) (6), respectively, in greater than 60% yields. Treatment of 3 with 2 equiv of the crown ether 12crown-4 affords the charge-separated salt [Sr(H 3 BNMe 2 BH 3 )(12-crown-4) 2 ][H 3 BNMe 2 BH 3 ] (7). Crystal structures of all the Lewis base adducts are described. Compounds 2−6 all possess chelating κ 2 -BH 3 NMe 2 BH 3 -κ 2 groups, in which two hydrogen atoms on each boron center are bound to strontium. Compound 6 is dinuclear because each metal atom is also coordinated to one hydrogen atom on a BH 3 NMe 2 BH 3 − ligand that chelates to the neighboring metal center. Compound 7 possesses an unusual κ 1 -BH 3 NMe 2 BH 3 − group owing to the near-complete encapsulation of the Sr atom by two 12-crown-4 molecules; the other BH 3 NMe 2 BH 3 − anion is a charge-separated counterion. When they are heated, the diglyme and tmeda compounds 5 and 6 melt without decomposition and can be sublimed readily under reduced pressure (1 Torr) at 120 °C. The diglyme and tmeda adducts are some of the most volatile strontium compounds known and are promising candidates as CVD precursors for the growth of strontium-containing thin films.

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Section: ■ Results and Discussionsupporting

confidence: 81%

Section: ■ Results and Discussionsupporting

confidence: 74%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Synthesis and Characterization of Strontium N,N-Dimethylaminodiboranates as Possible Chemical Vapor Deposition Precursors

Dunbar

Girolami

2020

Inorg. Chem.

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“…111,112 Hydrocarbon-soluble b-diketiminato model systems for the calcium-amidoborane-ammine system have also been prepared while a series of barium (N,N-dimethylamino)diboranates has also been described. 113,114 Several calcium bis(tetraethylaluminate) complexes with N-donor ligands have been reported. 115 Alkali and alkaline earth metals have been found to be efficiently activated in aromatic hydrocarbons or substituted 1,3-dienes to produce well-defined mononuclear diene complexes of calcium, strontium, and barium.…”

Section: Group 16 Donorsmentioning

confidence: 99%

Alkaline and alkaline earth metals

Hill

2013

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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N‐Heterocyclic Carbene‐Assisted Reversible Migratory Coupling of Aminoborane at Magnesium

et al. 2022

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A combined synthetic and theoretical investigation of N-heterocyclic carbene (NHC) adducts of magnesium amidoboranes is presented, which involves a rare example of reversible migratory insertion within a normal valent s-block element. The reaction of (NHC)Mg(N(SiMe 3 ) 2 ) 2 (1) and dimethylamine borane yields the tris(amide) adduct (NHCÀ BN)Mg(NMe 2 BH 3 )(N(SiMe 3 ) 2 ) (2; NHCÀ BN = NHCÀ BH 2 NMe 2 ). In addition to Me 2 N=BH 2 capture at the NHC CÀ Mg bond, mechanistic investigations suggest the likelihood of aminoborane migratory insertion from an RMg(NMe 2 BH 2 NMe 2 BH 3 ) intermediate. To elucidate these processes, the carbene complexes (NHC)Mg(NMe 2 BH 3 ) 2 ( 8) and (NHC)Mg(NMe 2 BH 2 NMe 2 BH 3 ) 2 (9) were synthesized, and a dynamic migration of Me 2 N=BH 2 between MgÀ N and NHC CÀ Mg bonds was observed in 9. This unusual reversible migratory insertion is presumably induced by dissimilar charge localization in the À {NMe 2 BH 2 NMe 2 BH 3 } anion, as well as the capacity of NHCs to reversibly capture Me 2 N=BH 2 in the presence of Lewis acidic magnesium species.

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Synthesis and Structural Diversity of Barium (N,N-Dimethylamino)diboranates

Cited by 19 publications

References 79 publications

Synthesis and Characterization of Strontium N,N-Dimethylaminodiboranates as Possible Chemical Vapor Deposition Precursors

Synthesis and Characterization of Strontium N,N-Dimethylaminodiboranates as Possible Chemical Vapor Deposition Precursors

Alkaline and alkaline earth metals

N‐Heterocyclic Carbene‐Assisted Reversible Migratory Coupling of Aminoborane at Magnesium

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