Lanthanide <i>N</i>,<i>N</i>-Dimethylaminodiboranates: Highly Volatile Precursors for the Deposition of Lanthanide-Containing Thin Films

Daly, Scott R.; Kim, Do Young; Yang, Yu; Abelson, John R.; Girolami, Gregory S.

doi:10.1021/ja9098005

Cited by 49 publications

(68 citation statements)

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“…Some derivatives of these compounds also have high coordination numbers, such as the 14-coordinate tetrahydrofuran complex [U(BH 4 ) 4 (thf) 2 ]. This compound extends our recent studies of a new class of chelating borohydride ligands, that is, the aminodiboranates, [23][24][25][26] some of which form highly volatile complexes that are useful as precursors for the chemical vapor deposition of thin films. [16,22] Herein, we report the synthesis, single-crystal X-ray and neutron diffraction studies, and DFT investigations of the first 15-coordinate complex.…”

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confidence: 58%

“…[21] No complex of any kind, however, has been definitively shown to adopt a Werner coordination number higher than 14. [25,26] Reaction of ThCl 4 with four equivalents of sodium N,Ndimethylaminodiboranate, Na(H 3 BNMe 2 BH 3 ), in tetrahydrofuran produced [Th(H 3 BNMe 2 BH 3 ) 4 ] (1), which could be isolated as colorless prisms by crystallization from diethyl ether. DFT calculations suggest that this complex may adopt a 16-coordinate structure in the gas phase.…”

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confidence: 99%

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Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H₃BNMe₂BH₃)₄]

et al. 2010

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Verrückt nach H‐Atomen: Röntgen‐ und Neutronenbeugungsdaten für Einkristalle belegen, dass das Th‐Zentrum in der Titelverbindung 1 (Th orange, B beige, N violett, C schwarz, H blau) Bindungen zu 15 H‐Atomen eingeht. Somit ist 1 der erste kristallographisch charakterisierte Komplex mit einer Werner‐Koordinationszahl von fünfzehn. DFT‐Rechnungen sprechen dafür, dass 1 in der Gasphase eine vollsymmetrische 16‐fach koordinierte Struktur einnimmt.

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Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H₃BNMe₂BH₃)₄]

et al. 2010

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“…59 The divalent and trivalent products can be easily distinguished by their colors. The Eu 2þ complex 1 is off-white, whereas its Eu 3þ analogue is yellow; for ytterbium, the colors are reversed: the Yb 2þ complex 2 is intensely yellow, whereas the Yb 3þ analogue is pale-yellow.…”

Section: Resultsmentioning

confidence: 99%

“…[55][56][57][58] We have previously shown that N, N-dimethylaminodiboranate (DMADB) complexes of trivalent lanthanide are highly volatile and useful as chemical vapor deposition and atomic layer deposition precursors to lanthanide-containing thin films. 59 We now describe the synthesis, characterization, and molecular structures of divalent lanthanide N,N-dimethylaminodiboranates. In several of these reactions, the DMADB ligand serves simultaneously as a ligand and as a reductant.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Structures of Divalent Europium and Ytterbium N,N-Dimethylaminodiboranates

Daly

Girolami

2010

Inorg. Chem.

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Treatment of the trichlorides EuCl(3) and YbCl(3) with Na(H(3)BNMe(2)BH(3)) in tetrahydrofuran (THF) results in a reduction to the corresponding divalent europium and ytterbium N,N-dimethylaminodiboranate (DMADB) complexes Eu(H(3)BNMe(2)BH(3))(2)(THF)(2) (1) and Yb(H(3)BNMe(2)BH(3))(2)(THF)(2) (2), which can be separated from trivalent Ln(H(3)BNMe(2)BH(3))(3)(THF) byproducts by extraction and crystallization from pentane. No other lanthanide trihalides react with Na(H(3)BNMe(2)BH(3)) to afford divalent products. Compounds 1 and 2 can also be prepared from the divalent lanthanide iodides EuI(2) and YbI(2) in higher yield and without the need to separate them from trivalent species. Treatment of 1 and 2 with an excess of 1,2-dimethoxyethane (DME) in pentane affords the new species Eu(H(3)BNMe(2)BH(3))(2)(DME)(2) (3) and Yb(H(3)BNMe(2)BH(3))(2)(DME) (4). Compound 1 is dinuclear: each metal center is bound to two chelating DMADB ligands, one of which also bridges to the other metal. Overall, the coordination geometry about each Eu atom can be described as a distorted pentagonal bipyramid, with five B atoms from the DMADB ligands occupying the equatorial sites and two THF molecules occupying the axial sites. Unlike 1, compound 2 is monomeric owing to the smaller radius of Yb(II) versus Eu(II); the B and O atoms describe a distorted cis octahedron. The Eu(DME) complex 3 is also monomeric; both DMADB ligands and both DME molecules chelate to the metal center. The four B atoms and the four O atoms describe a distorted square antiprism, with the O atoms occupying one square face and the B atoms occupying the other. In addition to X-ray crystallographic studies, IR, NMR, and mass spectrometric data are reported for all four new compounds.

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“…31 Consequently, lanthanide complexes containing DMADB ligands are among the most volatile compounds known for these elements. 32,33 Several M(DMADB) 3 complexes with trivalent lanthanides (all except promethium) and an actinide (uranium) have been reported. 31−33 Because the DMADB ligand can chelate to or bridge between two metal centers, a variety of solid-state structures have been observed depending on the size of the M 3+ ion: the coordination number increases from 12 to 14 as the ionic radius of the metal center becomes larger.…”

Section: ■ Introductionmentioning

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Volatilities of Actinide and Lanthanide N,N-Dimethylaminodiboranate Chemical Vapor Deposition Precursors: A DFT Study

et al. 2012

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N,N-Dimethylaminodiboranate complexes with praseodymium, samarium, erbium, and uranium, which are potential chemical vapor deposition precursors for the deposition of metal boride and oxide thin films, have been investigated by DFT guided by field-ionization mass spectroscopy experiments. The calculations indicate that the volatilities of these complexes are correlated with the M−H bond strengths as determined by Mayer bond order analysis. The geometries of the gas-phase monomeric, dimeric, and trimeric species seen in field-ionization mass spectroscopy experiments were identified using DFT calculations, and the relative stabilities of these oligomers were assessed to understand how the lanthanide aminodiboranates depolymerize to their respective volatile forms during sublimation. ■ INTRODUCTIONLanthanide-containing materials, such as lanthanide oxides and borides, have interesting optical, 1−3 magnetic, 4−6 and electrical 4,7,8 properties that make them useful for technological applications such as capacitors, field effect transistors, displays, thermoelectric devices, light-emitting diodes, and lasers. For many of these applications, defect-free thin films are necessary, and in some cases it is crucial to deposit the films uniformly onto substrates with high aspect ratios. 9 To achieve these results, there is much interest in developing better precursors for the chemical vapor deposition (CVD) and atomic layer deposition (ALD) of lanthanide-containing thin films. 10,11 For transition metals, some of the most volatile compounds known are homoleptic compounds containing the borohydride ligand, BH 4 − , and these have been shown to be useful CVD precursors. 12−20 Homoleptic borohydride compounds of the lanthanides are known but they are not particularly volatile 21−25 because their solid state structures are polymeric. 26−28 By comparison, actinide borohydrides in the +4 oxidation state such as U(BH 4 ) 4 are reasonably volatile despite the fact that some of them are also polymeric in the solid state. 29 Recently, a new class of metal borohydrides has been described that contain the N,N-dimethylaminodiboranate anion, H 3 BNMe 2 BH 3 − (DMADB) (Figure 1). 30−32 DMADB is a polydentate ligand capable of chelating a single metal center or bridging between two metal centers. Compared to the smaller BH 4 − ligand, the DMADB ligand better saturates the coordination sphere of large metals in lower oxidation states. 31 Consequently, lanthanide complexes containing DMADB ligands are among the most volatile compounds known for these elements. 32,33 Figure 1. Ball and stick (left) and schematic (right) structure of the N,N-dimethylaminodiboranate (DMADB) ligand. Color code: Nitrogen in blue, carbon in gray, boron in bronze, and hydrogen in white. Article pubs.acs.org/JPCC

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Lanthanide N,N-Dimethylaminodiboranates: Highly Volatile Precursors for the Deposition of Lanthanide-Containing Thin Films

Cited by 49 publications

References 35 publications

Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H₃BNMe₂BH₃)₄]

Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H₃BNMe₂BH₃)₄]

Synthesis, Characterization, and Structures of Divalent Europium and Ytterbium N,N-Dimethylaminodiboranates

Volatilities of Actinide and Lanthanide N,N-Dimethylaminodiboranate Chemical Vapor Deposition Precursors: A DFT Study

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Lanthanide N,N-Dimethylaminodiboranates: Highly Volatile Precursors for the Deposition of Lanthanide-Containing Thin Films

Cited by 49 publications

References 35 publications

Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H3BNMe2BH3)4]

Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H3BNMe2BH3)4]

Synthesis, Characterization, and Structures of Divalent Europium and Ytterbium N,N-Dimethylaminodiboranates

Volatilities of Actinide and Lanthanide N,N-Dimethylaminodiboranate Chemical Vapor Deposition Precursors: A DFT Study

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Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H₃BNMe₂BH₃)₄]

Synthesis and Properties of a Fifteen‐Coordinate Complex: The Thorium Aminodiboranate [Th(H₃BNMe₂BH₃)₄]