Thermal dihydrogen elimination from Cp*2Yb(4,5- diazafluorene)

Grégory Nocton; Corwin H. Booth; Laurent Maron; Richard A. Andersen

doi:10.1021/om300876b

Thermal dihydrogen elimination from Cp*₂Yb(4,5- diazafluorene)

Grégory Nocton
, Corwin H. Booth
, Laurent Maron
, Richard A. Andersen

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

Abstract

The reaction of 4,5-diazafluorene with Cp*₂Yb(OEt ₂), where Cp* is pentamethylcyclopentadienyl, affords the isolable adduct Cp*₂Yb(4,5-diazafluorene) (1), which slowly eliminates H₂ to form Cp*₂Yb(4,5-diazafluorenyl) (2); the net reaction is therefore 1 → 2 + H^•. The ytterbium atom in 1 is shown to be intermediate valent by variable-temperature L_III-edge X-ray absorption near-edge (XANES) spectroscopy, consistent with its low effective magnetic moment (μ_eff). The experimental studies are supported by complete active space self-consistent field (CASSCF) calculations, showing that two open-shell singlets lie below the triplet state. The two open-shell singlets are calculated to be multiconfigurational and closely spaced, in agreement with the observed temperature dependence of the XANES and χ data, which are fit to a Boltzmann distribution. A mechanism for dihydrogen formation is proposed on the basis of kinetic and labeling studies to involve the bimetallic complex (Cp*₂Yb)₂(4,5- diazafluorenyl)₂, in which the heterocyclic amine ligands are joined by a carbon-carbon bond at C(9)-C(9′).

Original language	English
Pages (from-to)	1150-1158
Number of pages	9
Journal	Organometallics
Volume	32
Issue number	5
DOIs	https://doi.org/10.1021/om300876b
Publication status	Published - 11 Mar 2013
Externally published	Yes

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@article{e183249e62114a6f9db5f6a24e13ae2c,

title = "Thermal dihydrogen elimination from Cp*2Yb(4,5- diazafluorene)",

abstract = "The reaction of 4,5-diazafluorene with Cp*2Yb(OEt 2), where Cp* is pentamethylcyclopentadienyl, affords the isolable adduct Cp*2Yb(4,5-diazafluorene) (1), which slowly eliminates H2 to form Cp*2Yb(4,5-diazafluorenyl) (2); the net reaction is therefore 1 → 2 + H•. The ytterbium atom in 1 is shown to be intermediate valent by variable-temperature LIII-edge X-ray absorption near-edge (XANES) spectroscopy, consistent with its low effective magnetic moment (μeff). The experimental studies are supported by complete active space self-consistent field (CASSCF) calculations, showing that two open-shell singlets lie below the triplet state. The two open-shell singlets are calculated to be multiconfigurational and closely spaced, in agreement with the observed temperature dependence of the XANES and χ data, which are fit to a Boltzmann distribution. A mechanism for dihydrogen formation is proposed on the basis of kinetic and labeling studies to involve the bimetallic complex (Cp*2Yb)2(4,5- diazafluorenyl)2, in which the heterocyclic amine ligands are joined by a carbon-carbon bond at C(9)-C(9′).",

author = "Gr{\'e}gory Nocton and Booth, \{Corwin H.\} and Laurent Maron and Andersen, \{Richard A.\}",

year = "2013",

month = mar,

day = "11",

doi = "10.1021/om300876b",

language = "English",

volume = "32",

pages = "1150--1158",

journal = "Organometallics",

issn = "0276-7333",

number = "5",

}

TY - JOUR

T1 - Thermal dihydrogen elimination from Cp*2Yb(4,5- diazafluorene)

AU - Nocton, Grégory

AU - Booth, Corwin H.

AU - Maron, Laurent

AU - Andersen, Richard A.

PY - 2013/3/11

Y1 - 2013/3/11

N2 - The reaction of 4,5-diazafluorene with Cp*2Yb(OEt 2), where Cp* is pentamethylcyclopentadienyl, affords the isolable adduct Cp*2Yb(4,5-diazafluorene) (1), which slowly eliminates H2 to form Cp*2Yb(4,5-diazafluorenyl) (2); the net reaction is therefore 1 → 2 + H•. The ytterbium atom in 1 is shown to be intermediate valent by variable-temperature LIII-edge X-ray absorption near-edge (XANES) spectroscopy, consistent with its low effective magnetic moment (μeff). The experimental studies are supported by complete active space self-consistent field (CASSCF) calculations, showing that two open-shell singlets lie below the triplet state. The two open-shell singlets are calculated to be multiconfigurational and closely spaced, in agreement with the observed temperature dependence of the XANES and χ data, which are fit to a Boltzmann distribution. A mechanism for dihydrogen formation is proposed on the basis of kinetic and labeling studies to involve the bimetallic complex (Cp*2Yb)2(4,5- diazafluorenyl)2, in which the heterocyclic amine ligands are joined by a carbon-carbon bond at C(9)-C(9′).

AB - The reaction of 4,5-diazafluorene with Cp*2Yb(OEt 2), where Cp* is pentamethylcyclopentadienyl, affords the isolable adduct Cp*2Yb(4,5-diazafluorene) (1), which slowly eliminates H2 to form Cp*2Yb(4,5-diazafluorenyl) (2); the net reaction is therefore 1 → 2 + H•. The ytterbium atom in 1 is shown to be intermediate valent by variable-temperature LIII-edge X-ray absorption near-edge (XANES) spectroscopy, consistent with its low effective magnetic moment (μeff). The experimental studies are supported by complete active space self-consistent field (CASSCF) calculations, showing that two open-shell singlets lie below the triplet state. The two open-shell singlets are calculated to be multiconfigurational and closely spaced, in agreement with the observed temperature dependence of the XANES and χ data, which are fit to a Boltzmann distribution. A mechanism for dihydrogen formation is proposed on the basis of kinetic and labeling studies to involve the bimetallic complex (Cp*2Yb)2(4,5- diazafluorenyl)2, in which the heterocyclic amine ligands are joined by a carbon-carbon bond at C(9)-C(9′).

U2 - 10.1021/om300876b

DO - 10.1021/om300876b

M3 - Article

AN - SCOPUS:84874912738

SN - 0276-7333

VL - 32

SP - 1150

EP - 1158

JO - Organometallics

JF - Organometallics

IS - 5

ER -

Thermal dihydrogen elimination from Cp*2Yb(4,5- diazafluorene)

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Thermal dihydrogen elimination from Cp*₂Yb(4,5- diazafluorene)