Parahydrogen derived illumination of pyridine based coordination products obtained from reactions involving rhodium phosphine complexes

Rongrong Zhou; Juan A. Aguilar; Adrian Charlton; Simon B. Duckett; Paul I P Elliott; Rathika Kandiah

doi:10.1039/b508149a

Parahydrogen derived illumination of pyridine based coordination products obtained from reactions involving rhodium phosphine complexes

Rongrong Zhou, Juan A. Aguilar, Adrian Charlton, Simon B. Duckett, Paul I P Elliott, Rathika Kandiah

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

13 Citations (Scopus)

Abstract

The reactions of RhCl(PBz₃)₃ with H₂ and pyridine or 4-methylpyridine yield RhCl(H)₂(PBz₃) ₂(py) and RhCl(H)₂(PBz₃)₂(4-Me-py), respectively. These species undergo hydride site exchange via the loss of the pyridyl donor and formation of RhCl(H)₂(PBz₃)₂ which contains equivalent hydride ligands; for the py system the activation free energy, ΔG₃₀₀,^‡ is 57.4 ± 0.1 kJ mol^-1 while for 4-Me-py the value is 59.6 ± 0.3 kJ mol ^-1. These products only showed parahydrogen enhancement in the corresponding hydride resonances when a sacrificial substrate was added to promote hydrogen cycling. When RhCl(PPh₃)₃ was used as the precursor similar observations were made, while when RhCl(PCy ₃)₂(C₂H₄) was examined, H ₂ addition led to the formation of the binuclear complex (H) ₂Rh(PCy₃)₂(μ-Cl)₂Rh(H) ₂(PCy₃)₂ which was differentiated from RhCl(H)₂(PCy₃)₂ on the basis of the similarity in diffusion coefficient (5.5 × 10^-9 m² s ^-1) to that of (H)₂Rh(PPh₃) ₂(μ-Cl)₂Rh(PPh₃)₂ (5.3 × 10^-9 m² s^-1). The detection of RhCl(H) ₂(PCy₃)₂(py) was facilitated when pyridine was added to a solution of RhCl(PCy₃)₂(C₂H ₄) before the introduction of H₂. During these reactions trace amounts of the double substitution products, RhCl(H) ₂(phosphine)(py)₂, were also detected.

Original language	English
Pages (from-to)	3773-3779
Number of pages	7
Journal	Dalton Transactions
Issue number	23
Early online date	8 Sept 2005
DOIs	https://doi.org/10.1039/b508149a
Publication status	Published - 7 Dec 2005
Externally published	Yes

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@article{4515934e06ca4886846d00af7fb91ab6,

title = "Parahydrogen derived illumination of pyridine based coordination products obtained from reactions involving rhodium phosphine complexes",

abstract = "The reactions of RhCl(PBz3)3 with H2 and pyridine or 4-methylpyridine yield RhCl(H)2(PBz3) 2(py) and RhCl(H)2(PBz3)2(4-Me-py), respectively. These species undergo hydride site exchange via the loss of the pyridyl donor and formation of RhCl(H)2(PBz3)2 which contains equivalent hydride ligands; for the py system the activation free energy, ΔG300,‡ is 57.4 ± 0.1 kJ mol-1 while for 4-Me-py the value is 59.6 ± 0.3 kJ mol -1. These products only showed parahydrogen enhancement in the corresponding hydride resonances when a sacrificial substrate was added to promote hydrogen cycling. When RhCl(PPh3)3 was used as the precursor similar observations were made, while when RhCl(PCy 3)2(C2H4) was examined, H 2 addition led to the formation of the binuclear complex (H) 2Rh(PCy3)2(μ-Cl)2Rh(H) 2(PCy3)2 which was differentiated from RhCl(H)2(PCy3)2 on the basis of the similarity in diffusion coefficient (5.5 × 10-9 m2 s -1) to that of (H)2Rh(PPh3) 2(μ-Cl)2Rh(PPh3)2 (5.3 × 10-9 m2 s-1). The detection of RhCl(H) 2(PCy3)2(py) was facilitated when pyridine was added to a solution of RhCl(PCy3)2(C2H 4) before the introduction of H2. During these reactions trace amounts of the double substitution products, RhCl(H) 2(phosphine)(py)2, were also detected.",

author = "Rongrong Zhou and Aguilar, \{Juan A.\} and Adrian Charlton and Duckett, \{Simon B.\} and Elliott, \{Paul I P\} and Rathika Kandiah",

year = "2005",

month = dec,

day = "7",

doi = "10.1039/b508149a",

language = "English",

pages = "3773--3779",

journal = "Dalton Transactions",

issn = "1477-9226",

publisher = "Royal Society of Chemistry",

number = "23",

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TY - JOUR

T1 - Parahydrogen derived illumination of pyridine based coordination products obtained from reactions involving rhodium phosphine complexes

AU - Zhou, Rongrong

AU - Aguilar, Juan A.

AU - Charlton, Adrian

AU - Duckett, Simon B.

AU - Elliott, Paul I P

AU - Kandiah, Rathika

PY - 2005/12/7

Y1 - 2005/12/7

N2 - The reactions of RhCl(PBz3)3 with H2 and pyridine or 4-methylpyridine yield RhCl(H)2(PBz3) 2(py) and RhCl(H)2(PBz3)2(4-Me-py), respectively. These species undergo hydride site exchange via the loss of the pyridyl donor and formation of RhCl(H)2(PBz3)2 which contains equivalent hydride ligands; for the py system the activation free energy, ΔG300,‡ is 57.4 ± 0.1 kJ mol-1 while for 4-Me-py the value is 59.6 ± 0.3 kJ mol -1. These products only showed parahydrogen enhancement in the corresponding hydride resonances when a sacrificial substrate was added to promote hydrogen cycling. When RhCl(PPh3)3 was used as the precursor similar observations were made, while when RhCl(PCy 3)2(C2H4) was examined, H 2 addition led to the formation of the binuclear complex (H) 2Rh(PCy3)2(μ-Cl)2Rh(H) 2(PCy3)2 which was differentiated from RhCl(H)2(PCy3)2 on the basis of the similarity in diffusion coefficient (5.5 × 10-9 m2 s -1) to that of (H)2Rh(PPh3) 2(μ-Cl)2Rh(PPh3)2 (5.3 × 10-9 m2 s-1). The detection of RhCl(H) 2(PCy3)2(py) was facilitated when pyridine was added to a solution of RhCl(PCy3)2(C2H 4) before the introduction of H2. During these reactions trace amounts of the double substitution products, RhCl(H) 2(phosphine)(py)2, were also detected.

AB - The reactions of RhCl(PBz3)3 with H2 and pyridine or 4-methylpyridine yield RhCl(H)2(PBz3) 2(py) and RhCl(H)2(PBz3)2(4-Me-py), respectively. These species undergo hydride site exchange via the loss of the pyridyl donor and formation of RhCl(H)2(PBz3)2 which contains equivalent hydride ligands; for the py system the activation free energy, ΔG300,‡ is 57.4 ± 0.1 kJ mol-1 while for 4-Me-py the value is 59.6 ± 0.3 kJ mol -1. These products only showed parahydrogen enhancement in the corresponding hydride resonances when a sacrificial substrate was added to promote hydrogen cycling. When RhCl(PPh3)3 was used as the precursor similar observations were made, while when RhCl(PCy 3)2(C2H4) was examined, H 2 addition led to the formation of the binuclear complex (H) 2Rh(PCy3)2(μ-Cl)2Rh(H) 2(PCy3)2 which was differentiated from RhCl(H)2(PCy3)2 on the basis of the similarity in diffusion coefficient (5.5 × 10-9 m2 s -1) to that of (H)2Rh(PPh3) 2(μ-Cl)2Rh(PPh3)2 (5.3 × 10-9 m2 s-1). The detection of RhCl(H) 2(PCy3)2(py) was facilitated when pyridine was added to a solution of RhCl(PCy3)2(C2H 4) before the introduction of H2. During these reactions trace amounts of the double substitution products, RhCl(H) 2(phosphine)(py)2, were also detected.

UR - https://www.scopus.com/pages/publications/29144443871

UR - http://pubs.rsc.org/en/journals/journalissues/dt#!recentarticles

U2 - 10.1039/b508149a

DO - 10.1039/b508149a

M3 - Article

AN - SCOPUS:29144443871

SN - 1477-9226

SP - 3773

EP - 3779

JO - Dalton Transactions

JF - Dalton Transactions

IS - 23

ER -

Parahydrogen derived illumination of pyridine based coordination products obtained from reactions involving rhodium phosphine complexes

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