Real time infrared spectroscopic probe of the reactions of Fe(CO)3 and Fe(CO)4 with Ni in the gas phase

Jiaqiang Wang; Gregory T. Long; Eric Weitz

doi:10.1021/jp003096s

Real time infrared spectroscopic probe of the reactions of Fe(CO)₃ and Fe(CO)₄ with Ni in the gas phase

Jiaqiang Wang^*, Gregory T. Long, Eric Weitz

^*Corresponding author for this work

Chemistry

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

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Abstract

Time-resolved infrared absorption spectroscopy has been used to study the gas-phase reactions of Fe(CO)₃, Fe(CO)₃N₂, and Fe(CO)₄ with N₂, where Fe(CO)₃ is generated by 308 nm laser photolysis of Fe(CO)₅. The heretofore unknown complex Fe(CO)₃(N₂)₂ forms by addition of N₂ to Fe(CO)₃N₂ with a rate constant of (5.4 ± 1.8) × 10^-16 cc molecule^-1 s^-1. This rate constant is much smaller than is typical for the addition of small ligands to coordinately unsaturated metal carbonyls, and data are consistent with this reaction being activated. The bond dissociation energy (BDE) for the loss of a N₂ ligand from Fe(CO)₄N₂ is 17.6 ± 1.8 kcal mol^-1. The activation energy for the loss of N₂ from Fe(CO)₃(N₂)₂ is 14.1 ± 5.2 kcal mol^-1. The kinetics of the system are consistent with a model that involves equilibria between Fe(CO)₃, Fe(CO)₃N₂, and Fe(CO)₃-(N₂)₂ as well as reactions of coordinatively unsaturated species with Fe(CO)₅. Using this kinetic model, an upper limit for the BDE for the Fe-N₂ bond in Fe(CO)₃N₂ has been estimated and the BDE for the Fe-N₂ bond in Fe(CO)₃(N₂)₂ has been determined under the assumption that one of the relevant reactions has a minimal activation energy.

Original language	English (US)
Pages (from-to)	3765-3772
Number of pages	8
Journal	Journal of Physical Chemistry A
Volume	105
Issue number	15
DOIs	https://doi.org/10.1021/jp003096s
State	Published - Apr 19 2001

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Physical and Theoretical Chemistry

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@article{c1da7b8b30d440e58181fb55010efada,

title = "Real time infrared spectroscopic probe of the reactions of Fe(CO)3 and Fe(CO)4 with Ni in the gas phase",

abstract = "Time-resolved infrared absorption spectroscopy has been used to study the gas-phase reactions of Fe(CO)3, Fe(CO)3N2, and Fe(CO)4 with N2, where Fe(CO)3 is generated by 308 nm laser photolysis of Fe(CO)5. The heretofore unknown complex Fe(CO)3(N2)2 forms by addition of N2 to Fe(CO)3N2 with a rate constant of (5.4 ± 1.8) × 10-16 cc molecule-1 s-1. This rate constant is much smaller than is typical for the addition of small ligands to coordinately unsaturated metal carbonyls, and data are consistent with this reaction being activated. The bond dissociation energy (BDE) for the loss of a N2 ligand from Fe(CO)4N2 is 17.6 ± 1.8 kcal mol-1. The activation energy for the loss of N2 from Fe(CO)3(N2)2 is 14.1 ± 5.2 kcal mol-1. The kinetics of the system are consistent with a model that involves equilibria between Fe(CO)3, Fe(CO)3N2, and Fe(CO)3-(N2)2 as well as reactions of coordinatively unsaturated species with Fe(CO)5. Using this kinetic model, an upper limit for the BDE for the Fe-N2 bond in Fe(CO)3N2 has been estimated and the BDE for the Fe-N2 bond in Fe(CO)3(N2)2 has been determined under the assumption that one of the relevant reactions has a minimal activation energy.",

author = "Jiaqiang Wang and Long, {Gregory T.} and Eric Weitz",

year = "2001",

month = apr,

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doi = "10.1021/jp003096s",

language = "English (US)",

volume = "105",

pages = "3765--3772",

journal = "Journal of Physical Chemistry A",

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T1 - Real time infrared spectroscopic probe of the reactions of Fe(CO)3 and Fe(CO)4 with Ni in the gas phase

AU - Wang, Jiaqiang

AU - Long, Gregory T.

AU - Weitz, Eric

PY - 2001/4/19

Y1 - 2001/4/19

N2 - Time-resolved infrared absorption spectroscopy has been used to study the gas-phase reactions of Fe(CO)3, Fe(CO)3N2, and Fe(CO)4 with N2, where Fe(CO)3 is generated by 308 nm laser photolysis of Fe(CO)5. The heretofore unknown complex Fe(CO)3(N2)2 forms by addition of N2 to Fe(CO)3N2 with a rate constant of (5.4 ± 1.8) × 10-16 cc molecule-1 s-1. This rate constant is much smaller than is typical for the addition of small ligands to coordinately unsaturated metal carbonyls, and data are consistent with this reaction being activated. The bond dissociation energy (BDE) for the loss of a N2 ligand from Fe(CO)4N2 is 17.6 ± 1.8 kcal mol-1. The activation energy for the loss of N2 from Fe(CO)3(N2)2 is 14.1 ± 5.2 kcal mol-1. The kinetics of the system are consistent with a model that involves equilibria between Fe(CO)3, Fe(CO)3N2, and Fe(CO)3-(N2)2 as well as reactions of coordinatively unsaturated species with Fe(CO)5. Using this kinetic model, an upper limit for the BDE for the Fe-N2 bond in Fe(CO)3N2 has been estimated and the BDE for the Fe-N2 bond in Fe(CO)3(N2)2 has been determined under the assumption that one of the relevant reactions has a minimal activation energy.

AB - Time-resolved infrared absorption spectroscopy has been used to study the gas-phase reactions of Fe(CO)3, Fe(CO)3N2, and Fe(CO)4 with N2, where Fe(CO)3 is generated by 308 nm laser photolysis of Fe(CO)5. The heretofore unknown complex Fe(CO)3(N2)2 forms by addition of N2 to Fe(CO)3N2 with a rate constant of (5.4 ± 1.8) × 10-16 cc molecule-1 s-1. This rate constant is much smaller than is typical for the addition of small ligands to coordinately unsaturated metal carbonyls, and data are consistent with this reaction being activated. The bond dissociation energy (BDE) for the loss of a N2 ligand from Fe(CO)4N2 is 17.6 ± 1.8 kcal mol-1. The activation energy for the loss of N2 from Fe(CO)3(N2)2 is 14.1 ± 5.2 kcal mol-1. The kinetics of the system are consistent with a model that involves equilibria between Fe(CO)3, Fe(CO)3N2, and Fe(CO)3-(N2)2 as well as reactions of coordinatively unsaturated species with Fe(CO)5. Using this kinetic model, an upper limit for the BDE for the Fe-N2 bond in Fe(CO)3N2 has been estimated and the BDE for the Fe-N2 bond in Fe(CO)3(N2)2 has been determined under the assumption that one of the relevant reactions has a minimal activation energy.

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JF - Journal of Physical Chemistry A

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ER -

Real time infrared spectroscopic probe of the reactions of Fe(CO)₃ and Fe(CO)₄ with Ni in the gas phase

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