Mixed amido/imido/guanidinato complexes of niobium: Potential precursors for MOCVD of niobium nitride thin films

Arne Baunemann; Daniela Bekermann; Tobias B. Thiede; Harish Parala; Manuela Winter; Christian Gemel; Roland A. Fischer

doi:10.1039/b719688a

Mixed amido/imido/guanidinato complexes of niobium: Potential precursors for MOCVD of niobium nitride thin films

Arne Baunemann, Daniela Bekermann, Tobias B. Thiede, Harish Parala, Manuela Winter, Christian Gemel, Roland A. Fischer

Max-Planck-lnstitut für Kohlenforschung

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Abstract

Novel mixed amido/imido/guanidinato complexes of niobium are reported. The complexes were synthesized by insertion of two equivalents of di-isopropylcarbodiimide (i-Pr-cdi) or bis-cyclohexylcarbodiimide (Cy-cdi) respectively, into the niobium-amido bonds of [Nb(NR₂) ₃(N-t-Bu)] (1, R = Me; 2, R = Et) starting out from [NbCl ₃(N-t-Bu)(py)₂] and the respective LiNR₂ reagent (py = pyridine). Four representative examples of these mixed ligand amido/imido/guanidinato compounds were synthesized and were characterized by ¹H-NMR, ¹³C-NMR, ¹⁵N-NMR, CHN-analysis, mass spectrometry and infra-red spectroscopy. The molecular structures of [Nb(NR ₂){η²-(i-Pr-N)₂C(NR₂)} ₂(N-t-Bu)] (3, R = Me; 4, R = Et) in the solid state were determined by single-crystal X-ray diffraction studies and are discussed together with the molecular structure of the starting compound [Nb(NMe₂) ₃(N-t-Bu)] (1). The thermal properties of the new compounds depend on the substitution at the guanidinato ligand. Complexes of i-Pr-cdi are significantly more volatile than complexes of Cy-cdi as revealed by thermogravimetric analysis. Preliminary experiments using 3 as a single-molecule source for metal-organic chemical vapour deposition (MOCVD) in the absence of ammonia indicate the formation of the stoichiometric, and surprisingly carbon-free, cubic niobium nitride phase.

Original language	English
Pages (from-to)	3715-3722
Number of pages	8
Journal	Dalton Transactions
Issue number	28
DOIs	https://doi.org/10.1039/b719688a
State	Published - 2008
Externally published	Yes

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title = "Mixed amido/imido/guanidinato complexes of niobium: Potential precursors for MOCVD of niobium nitride thin films",

abstract = "Novel mixed amido/imido/guanidinato complexes of niobium are reported. The complexes were synthesized by insertion of two equivalents of di-isopropylcarbodiimide (i-Pr-cdi) or bis-cyclohexylcarbodiimide (Cy-cdi) respectively, into the niobium-amido bonds of [Nb(NR2) 3(N-t-Bu)] (1, R = Me; 2, R = Et) starting out from [NbCl 3(N-t-Bu)(py)2] and the respective LiNR2 reagent (py = pyridine). Four representative examples of these mixed ligand amido/imido/guanidinato compounds were synthesized and were characterized by 1H-NMR, 13C-NMR, 15N-NMR, CHN-analysis, mass spectrometry and infra-red spectroscopy. The molecular structures of [Nb(NR 2){η2-(i-Pr-N)2C(NR2)} 2(N-t-Bu)] (3, R = Me; 4, R = Et) in the solid state were determined by single-crystal X-ray diffraction studies and are discussed together with the molecular structure of the starting compound [Nb(NMe2) 3(N-t-Bu)] (1). The thermal properties of the new compounds depend on the substitution at the guanidinato ligand. Complexes of i-Pr-cdi are significantly more volatile than complexes of Cy-cdi as revealed by thermogravimetric analysis. Preliminary experiments using 3 as a single-molecule source for metal-organic chemical vapour deposition (MOCVD) in the absence of ammonia indicate the formation of the stoichiometric, and surprisingly carbon-free, cubic niobium nitride phase.",

author = "Arne Baunemann and Daniela Bekermann and Thiede, {Tobias B.} and Harish Parala and Manuela Winter and Christian Gemel and Fischer, {Roland A.}",

year = "2008",

doi = "10.1039/b719688a",

language = "English",

pages = "3715--3722",

journal = "Dalton Transactions",

issn = "1477-9226",

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T1 - Mixed amido/imido/guanidinato complexes of niobium

T2 - Potential precursors for MOCVD of niobium nitride thin films

AU - Baunemann, Arne

AU - Bekermann, Daniela

AU - Thiede, Tobias B.

AU - Parala, Harish

AU - Winter, Manuela

AU - Gemel, Christian

AU - Fischer, Roland A.

PY - 2008

Y1 - 2008

N2 - Novel mixed amido/imido/guanidinato complexes of niobium are reported. The complexes were synthesized by insertion of two equivalents of di-isopropylcarbodiimide (i-Pr-cdi) or bis-cyclohexylcarbodiimide (Cy-cdi) respectively, into the niobium-amido bonds of [Nb(NR2) 3(N-t-Bu)] (1, R = Me; 2, R = Et) starting out from [NbCl 3(N-t-Bu)(py)2] and the respective LiNR2 reagent (py = pyridine). Four representative examples of these mixed ligand amido/imido/guanidinato compounds were synthesized and were characterized by 1H-NMR, 13C-NMR, 15N-NMR, CHN-analysis, mass spectrometry and infra-red spectroscopy. The molecular structures of [Nb(NR 2){η2-(i-Pr-N)2C(NR2)} 2(N-t-Bu)] (3, R = Me; 4, R = Et) in the solid state were determined by single-crystal X-ray diffraction studies and are discussed together with the molecular structure of the starting compound [Nb(NMe2) 3(N-t-Bu)] (1). The thermal properties of the new compounds depend on the substitution at the guanidinato ligand. Complexes of i-Pr-cdi are significantly more volatile than complexes of Cy-cdi as revealed by thermogravimetric analysis. Preliminary experiments using 3 as a single-molecule source for metal-organic chemical vapour deposition (MOCVD) in the absence of ammonia indicate the formation of the stoichiometric, and surprisingly carbon-free, cubic niobium nitride phase.

AB - Novel mixed amido/imido/guanidinato complexes of niobium are reported. The complexes were synthesized by insertion of two equivalents of di-isopropylcarbodiimide (i-Pr-cdi) or bis-cyclohexylcarbodiimide (Cy-cdi) respectively, into the niobium-amido bonds of [Nb(NR2) 3(N-t-Bu)] (1, R = Me; 2, R = Et) starting out from [NbCl 3(N-t-Bu)(py)2] and the respective LiNR2 reagent (py = pyridine). Four representative examples of these mixed ligand amido/imido/guanidinato compounds were synthesized and were characterized by 1H-NMR, 13C-NMR, 15N-NMR, CHN-analysis, mass spectrometry and infra-red spectroscopy. The molecular structures of [Nb(NR 2){η2-(i-Pr-N)2C(NR2)} 2(N-t-Bu)] (3, R = Me; 4, R = Et) in the solid state were determined by single-crystal X-ray diffraction studies and are discussed together with the molecular structure of the starting compound [Nb(NMe2) 3(N-t-Bu)] (1). The thermal properties of the new compounds depend on the substitution at the guanidinato ligand. Complexes of i-Pr-cdi are significantly more volatile than complexes of Cy-cdi as revealed by thermogravimetric analysis. Preliminary experiments using 3 as a single-molecule source for metal-organic chemical vapour deposition (MOCVD) in the absence of ammonia indicate the formation of the stoichiometric, and surprisingly carbon-free, cubic niobium nitride phase.

UR - http://www.scopus.com/inward/record.url?scp=46949100282&partnerID=8YFLogxK

U2 - 10.1039/b719688a

DO - 10.1039/b719688a

M3 - Article

AN - SCOPUS:46949100282

SN - 1477-9226

SP - 3715

EP - 3722

JO - Dalton Transactions

JF - Dalton Transactions

IS - 28

ER -

Mixed amido/imido/guanidinato complexes of niobium: Potential precursors for MOCVD of niobium nitride thin films

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