Evaluation of attractive interactions in the second coordination sphere of iron complexes containing pendant amines

Qian Liao; Tianbiao Liu; Samantha I. Johnson; Christina M. Klug; Eric S. Wiedner; R. Morris Bullock; Daniel L. Dubois

doi:10.1039/c9dt00708c

Evaluation of attractive interactions in the second coordination sphere of iron complexes containing pendant amines

Qian Liao, Tianbiao Liu, Samantha I. Johnson, Christina M. Klug, Eric S. Wiedner, R. Morris Bullock, Daniel L. Dubois

Pacific Northwest National Laboratory

Research output: Contribution to journal › Article

2 Citations (Scopus)

Abstract

The interactions between pendant amines in the second coordination sphere and ligands in the first coordination sphere are important for understanding the structures and reactivity of complexes containing P ^R ₂ N ^R′ ₂ ligands, which have been shown to be highly active H ₂ oxidation/production catalysts. A series of [Fe(P ^Ph ₂ N ^Bn ₂ ) ₂ (X)(Y)] ⁿ⁺ complexes have been prepared and structurally characterized. These complexes have two different ligands with which the pendant amines of the diphosphine ligand can interact. The solid state structure of cis-Fe(P ^Ph ₂ N ^Bn ₂ ) ₂ Cl ₂ reveals that the six-membered rings adjacent to the P atoms are in a boat confirmation, resulting in close N⋯P distances that suggests the P atoms have a greater affinity for the lone pair of electrons on the N atom than chloride ligands. Similarly, boat conformations are observed for both rings adjacent to the hydride ligands of trans-[HFe(P ^Ph ₂ N ^Bn ₂ ) ₂ (CH ₃ CN)] ⁺ and trans-HFe(P ^Ph ₂ N ^Bn ₂ ) ₂ Cl, resulting in short N⋯H distances. Spectroscopic and computational studies of trans-[HFe(P ^Ph ₂ N ^Bn ₂ ) ₂ (CO)] ⁺ , trans-[HFe(P ^Ph ₂ N ^Bn ₂ )(P ^Ph ₂ N ^Bn ₂ H)(CO)] ²⁺ , and trans-[HFe(P ^Ph ₂ N ^Bn ₂ ) ₂ (H ₂ )] ⁺ indicate the complexes are more stable when the pendant amines in boat conformations are adjacent to the hydride ligand. These data suggest an attractor ordering of H ^- > CO > H ₂ > PR ₃ > Cl ^- ∼ CH ₃ CN.

Original language	English
Pages (from-to)	4867-4878
Number of pages	12
Journal	Dalton Transactions
Volume	48
Issue number	15
DOIs	https://doi.org/10.1039/c9dt00708c
Publication status	Published - Jan 1 2019

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ASJC Scopus subject areas

Inorganic Chemistry

Cite this

Liao, Q., Liu, T., Johnson, S. I., Klug, C. M., Wiedner, E. S., Morris Bullock, R., & Dubois, D. L. (2019). Evaluation of attractive interactions in the second coordination sphere of iron complexes containing pendant amines. Dalton Transactions, 48(15), 4867-4878. https://doi.org/10.1039/c9dt00708c

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title = "Evaluation of attractive interactions in the second coordination sphere of iron complexes containing pendant amines",

abstract = " The interactions between pendant amines in the second coordination sphere and ligands in the first coordination sphere are important for understanding the structures and reactivity of complexes containing P R 2 N R′ 2 ligands, which have been shown to be highly active H 2 oxidation/production catalysts. A series of [Fe(P Ph 2 N Bn 2 ) 2 (X)(Y)] n+ complexes have been prepared and structurally characterized. These complexes have two different ligands with which the pendant amines of the diphosphine ligand can interact. The solid state structure of cis-Fe(P Ph 2 N Bn 2 ) 2 Cl 2 reveals that the six-membered rings adjacent to the P atoms are in a boat confirmation, resulting in close N⋯P distances that suggests the P atoms have a greater affinity for the lone pair of electrons on the N atom than chloride ligands. Similarly, boat conformations are observed for both rings adjacent to the hydride ligands of trans-[HFe(P Ph 2 N Bn 2 ) 2 (CH 3 CN)] + and trans-HFe(P Ph 2 N Bn 2 ) 2 Cl, resulting in short N⋯H distances. Spectroscopic and computational studies of trans-[HFe(P Ph 2 N Bn 2 ) 2 (CO)] + , trans-[HFe(P Ph 2 N Bn 2 )(P Ph 2 N Bn 2 H)(CO)] 2+ , and trans-[HFe(P Ph 2 N Bn 2 ) 2 (H 2 )] + indicate the complexes are more stable when the pendant amines in boat conformations are adjacent to the hydride ligand. These data suggest an attractor ordering of H - > CO > H 2 > PR 3 > Cl - ∼ CH 3 CN. ",

author = "Qian Liao and Tianbiao Liu and Johnson, {Samantha I.} and Klug, {Christina M.} and Wiedner, {Eric S.} and {Morris Bullock}, R. and Dubois, {Daniel L.}",

year = "2019",

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doi = "10.1039/c9dt00708c",

language = "English",

volume = "48",

pages = "4867--4878",

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T1 - Evaluation of attractive interactions in the second coordination sphere of iron complexes containing pendant amines

AU - Liao, Qian

AU - Liu, Tianbiao

AU - Johnson, Samantha I.

AU - Klug, Christina M.

AU - Wiedner, Eric S.

AU - Morris Bullock, R.

AU - Dubois, Daniel L.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - The interactions between pendant amines in the second coordination sphere and ligands in the first coordination sphere are important for understanding the structures and reactivity of complexes containing P R 2 N R′ 2 ligands, which have been shown to be highly active H 2 oxidation/production catalysts. A series of [Fe(P Ph 2 N Bn 2 ) 2 (X)(Y)] n+ complexes have been prepared and structurally characterized. These complexes have two different ligands with which the pendant amines of the diphosphine ligand can interact. The solid state structure of cis-Fe(P Ph 2 N Bn 2 ) 2 Cl 2 reveals that the six-membered rings adjacent to the P atoms are in a boat confirmation, resulting in close N⋯P distances that suggests the P atoms have a greater affinity for the lone pair of electrons on the N atom than chloride ligands. Similarly, boat conformations are observed for both rings adjacent to the hydride ligands of trans-[HFe(P Ph 2 N Bn 2 ) 2 (CH 3 CN)] + and trans-HFe(P Ph 2 N Bn 2 ) 2 Cl, resulting in short N⋯H distances. Spectroscopic and computational studies of trans-[HFe(P Ph 2 N Bn 2 ) 2 (CO)] + , trans-[HFe(P Ph 2 N Bn 2 )(P Ph 2 N Bn 2 H)(CO)] 2+ , and trans-[HFe(P Ph 2 N Bn 2 ) 2 (H 2 )] + indicate the complexes are more stable when the pendant amines in boat conformations are adjacent to the hydride ligand. These data suggest an attractor ordering of H - > CO > H 2 > PR 3 > Cl - ∼ CH 3 CN.

AB - The interactions between pendant amines in the second coordination sphere and ligands in the first coordination sphere are important for understanding the structures and reactivity of complexes containing P R 2 N R′ 2 ligands, which have been shown to be highly active H 2 oxidation/production catalysts. A series of [Fe(P Ph 2 N Bn 2 ) 2 (X)(Y)] n+ complexes have been prepared and structurally characterized. These complexes have two different ligands with which the pendant amines of the diphosphine ligand can interact. The solid state structure of cis-Fe(P Ph 2 N Bn 2 ) 2 Cl 2 reveals that the six-membered rings adjacent to the P atoms are in a boat confirmation, resulting in close N⋯P distances that suggests the P atoms have a greater affinity for the lone pair of electrons on the N atom than chloride ligands. Similarly, boat conformations are observed for both rings adjacent to the hydride ligands of trans-[HFe(P Ph 2 N Bn 2 ) 2 (CH 3 CN)] + and trans-HFe(P Ph 2 N Bn 2 ) 2 Cl, resulting in short N⋯H distances. Spectroscopic and computational studies of trans-[HFe(P Ph 2 N Bn 2 ) 2 (CO)] + , trans-[HFe(P Ph 2 N Bn 2 )(P Ph 2 N Bn 2 H)(CO)] 2+ , and trans-[HFe(P Ph 2 N Bn 2 ) 2 (H 2 )] + indicate the complexes are more stable when the pendant amines in boat conformations are adjacent to the hydride ligand. These data suggest an attractor ordering of H - > CO > H 2 > PR 3 > Cl - ∼ CH 3 CN.

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U2 - 10.1039/c9dt00708c

DO - 10.1039/c9dt00708c

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SP - 4867

EP - 4878

JO - Dalton Transactions

JF - Dalton Transactions

SN - 1477-9226

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10.1039/c9dt00708c