An investigation into the photochemical reactions of MCp(CO)4 (Cp = η5-C5H5) and M(η5-C9H7)(CO)4 (η5-C9H7 = indenyl; M = Nb or Ta) with CO, H2 and N2 in solution at room temperature

G. I. Childs, David Grills, S. Gallagher, T. E. Bitterwolf, M. W. George

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Abstract

Time resolved step-scan FTIR spectroscopy (s2-FTIR) has been used to characterise MCp′(CO)3L (Cp′ = Cp or indenyl (η5-C9H7); M = Nb or Ta; L = n-heptane, H2 or N2) in solution at room temperature. TaCp′(CO)4 formed the classical dihydrides, TaCp′(CO)3H2 upon irradiation in n-heptane saturated with H2. However, photolysis of Nb(η5-C9H7)(CO)4 under the same conditions led to the non-classical complex, Nb(η5-C9H7)(CO)32-H2), whereas irradiation of NbCp(CO)4 resulted in both NbCp(CO)3H2 and NbCp(CO)32-H2). Photolysis of MCp′(CO)4 in n-heptane saturated with N2 resulted in formation of MCp′(CO)3(N2) in all cases. No evidence for disubstitution of these complexes was obtained in these s2-FTIR experiments. The rate constants for the reaction of M(η5-C9H7)(CO)3(n-C 7H16) with CO, H2 and N2 have been determined. Comparison of these rate constants with those obtained for the analogous cyclopentadienyl complexes showed that the indenyl complexes are more reactive (ca. 10 times). Additionally, the Nb(η5-C9H7)(CO)3(L) (L = η2-H2 or N2) complexes were found to be less stable (ca. 20-30 times) than NbCp(CO)3(L), and Ta(η5-C9H7)(CO)3(N 2) was more reactive (ca. 25 times) than TaCp(CO)3(N2).

Original languageEnglish
Pages (from-to)1711-1717
Number of pages7
JournalJournal of the Chemical Society, Dalton Transactions
Issue number11
Publication statusPublished - 2001

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Photochemical reactions
Carbon Monoxide
Temperature
Photolysis
Rate constants
Irradiation

ASJC Scopus subject areas

  • Chemistry(all)

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@article{3b1817700843496cbd45d8be00b888be,
title = "An investigation into the photochemical reactions of MCp(CO)4 (Cp = η5-C5H5) and M(η5-C9H7)(CO)4 (η5-C9H7 = indenyl; M = Nb or Ta) with CO, H2 and N2 in solution at room temperature",
abstract = "Time resolved step-scan FTIR spectroscopy (s2-FTIR) has been used to characterise MCp′(CO)3L (Cp′ = Cp or indenyl (η5-C9H7); M = Nb or Ta; L = n-heptane, H2 or N2) in solution at room temperature. TaCp′(CO)4 formed the classical dihydrides, TaCp′(CO)3H2 upon irradiation in n-heptane saturated with H2. However, photolysis of Nb(η5-C9H7)(CO)4 under the same conditions led to the non-classical complex, Nb(η5-C9H7)(CO)3(η 2-H2), whereas irradiation of NbCp(CO)4 resulted in both NbCp(CO)3H2 and NbCp(CO)3(η2-H2). Photolysis of MCp′(CO)4 in n-heptane saturated with N2 resulted in formation of MCp′(CO)3(N2) in all cases. No evidence for disubstitution of these complexes was obtained in these s2-FTIR experiments. The rate constants for the reaction of M(η5-C9H7)(CO)3(n-C 7H16) with CO, H2 and N2 have been determined. Comparison of these rate constants with those obtained for the analogous cyclopentadienyl complexes showed that the indenyl complexes are more reactive (ca. 10 times). Additionally, the Nb(η5-C9H7)(CO)3(L) (L = η2-H2 or N2) complexes were found to be less stable (ca. 20-30 times) than NbCp(CO)3(L), and Ta(η5-C9H7)(CO)3(N 2) was more reactive (ca. 25 times) than TaCp(CO)3(N2).",
author = "Childs, {G. I.} and David Grills and S. Gallagher and Bitterwolf, {T. E.} and George, {M. W.}",
year = "2001",
language = "English",
pages = "1711--1717",
journal = "Dalton Transactions",
issn = "1477-9226",
publisher = "Royal Society of Chemistry",
number = "11",

}

TY - JOUR

T1 - An investigation into the photochemical reactions of MCp(CO)4 (Cp = η5-C5H5) and M(η5-C9H7)(CO)4 (η5-C9H7 = indenyl; M = Nb or Ta) with CO, H2 and N2 in solution at room temperature

AU - Childs, G. I.

AU - Grills, David

AU - Gallagher, S.

AU - Bitterwolf, T. E.

AU - George, M. W.

PY - 2001

Y1 - 2001

N2 - Time resolved step-scan FTIR spectroscopy (s2-FTIR) has been used to characterise MCp′(CO)3L (Cp′ = Cp or indenyl (η5-C9H7); M = Nb or Ta; L = n-heptane, H2 or N2) in solution at room temperature. TaCp′(CO)4 formed the classical dihydrides, TaCp′(CO)3H2 upon irradiation in n-heptane saturated with H2. However, photolysis of Nb(η5-C9H7)(CO)4 under the same conditions led to the non-classical complex, Nb(η5-C9H7)(CO)3(η 2-H2), whereas irradiation of NbCp(CO)4 resulted in both NbCp(CO)3H2 and NbCp(CO)3(η2-H2). Photolysis of MCp′(CO)4 in n-heptane saturated with N2 resulted in formation of MCp′(CO)3(N2) in all cases. No evidence for disubstitution of these complexes was obtained in these s2-FTIR experiments. The rate constants for the reaction of M(η5-C9H7)(CO)3(n-C 7H16) with CO, H2 and N2 have been determined. Comparison of these rate constants with those obtained for the analogous cyclopentadienyl complexes showed that the indenyl complexes are more reactive (ca. 10 times). Additionally, the Nb(η5-C9H7)(CO)3(L) (L = η2-H2 or N2) complexes were found to be less stable (ca. 20-30 times) than NbCp(CO)3(L), and Ta(η5-C9H7)(CO)3(N 2) was more reactive (ca. 25 times) than TaCp(CO)3(N2).

AB - Time resolved step-scan FTIR spectroscopy (s2-FTIR) has been used to characterise MCp′(CO)3L (Cp′ = Cp or indenyl (η5-C9H7); M = Nb or Ta; L = n-heptane, H2 or N2) in solution at room temperature. TaCp′(CO)4 formed the classical dihydrides, TaCp′(CO)3H2 upon irradiation in n-heptane saturated with H2. However, photolysis of Nb(η5-C9H7)(CO)4 under the same conditions led to the non-classical complex, Nb(η5-C9H7)(CO)3(η 2-H2), whereas irradiation of NbCp(CO)4 resulted in both NbCp(CO)3H2 and NbCp(CO)3(η2-H2). Photolysis of MCp′(CO)4 in n-heptane saturated with N2 resulted in formation of MCp′(CO)3(N2) in all cases. No evidence for disubstitution of these complexes was obtained in these s2-FTIR experiments. The rate constants for the reaction of M(η5-C9H7)(CO)3(n-C 7H16) with CO, H2 and N2 have been determined. Comparison of these rate constants with those obtained for the analogous cyclopentadienyl complexes showed that the indenyl complexes are more reactive (ca. 10 times). Additionally, the Nb(η5-C9H7)(CO)3(L) (L = η2-H2 or N2) complexes were found to be less stable (ca. 20-30 times) than NbCp(CO)3(L), and Ta(η5-C9H7)(CO)3(N 2) was more reactive (ca. 25 times) than TaCp(CO)3(N2).

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M3 - Article

SP - 1711

EP - 1717

JO - Dalton Transactions

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