Sterically encumbered iron(II) thiolate complexes: Synthesis and structure of trigonal planar [Fe(SR)3]- (R = 2,4,6-t-Bu3C6H2) and Mössbauer spectra of two- and three-coordinate complexes

Frederick M. MacDonnell, Karin Ruhlandt, Jeffrey J. Ellison, R. H. Holm, Philip P. Power

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Abstract

The synthesis and structural characterization of three compounds containing three-coordinate Fe(II) and stabilized by sterically encumbered thiolate ligands are reported. Reaction of [Fe2(SC6H2-2,4,6-t-Bu3)4] (3) with LiSC6H2-2,4,6-t-Bu3 in ether/THF/hexane afforded [Li(THF)2(5)]·0.5C6H14 (5 = [Fe(SC6H2-2,4,6-t-Bu3)3] -). Addition of Ph4PCl to a reaction mixture in toluene followed by recrystallization of the product from acetonitrile yielded (Ph4P)[5]·2MeCN·C7H8. The compound [Fe3(SC6H2-2,4,6-t-Pr3) 4(N(SiMe3)2)2] was prepared by the reaction of [Fe(N(SiMe3)2)2] (6) with the thiol in toluene. [Li(THF)2(5)]·0.5C6H14 crystallizes in monoclinic space group P21/c with a = 9.809(2) Å, b = 22.507(5) Å, c = 29.553(5) Å, β = 95.72(2)°, and Z = 4 (130 K). (Ph4P)-[5]·2MeCN·C7H8 was obtained in monoclinic space group P21 with a = 17.538(5) Å, b = 14.912(4) Å, c = 17.608(5) Å, β = 115.71(3)°, and Z = 2 (143 K). These compounds contain the first example of mononuclear Fe(II) in a close approach to a trigonal planar [5] or a distorted trigonal planar [Li(THF)2(5)] sulfur coordination environment. In the Ph4P salt, [5] exhibits the mean values Fe-S = 2.274(9) Å and S-Fe-S = 120(3)°, while in [Li(THF)2(S)] the Li+ ion bridges two sulfur atoms, causing a lengthening (0.06-0.07 Å) of the Fe-S bridged bond lengths and constriction of the bridged S-Fe-S angle (92.2(1)°). Compound 6 crystallizes in P21/c with a = 14.521(5) Å, b = 41.60(2) Å, c = 14.241(4) Å, β = 100.42(2)°, and Z = 4 (130 K). The structure has a linear Fe32-SR)4 fragment with an almost linear Fe3 array involving the central Fe(II) atom in a severely distorted tetrahedral environment; the terminal Fe(II) atoms are three-coordinate and planar with terminal N(SiMe3)2 ligands. Complex 5 expands the family of homoleptic molecular Fe(II) thiolates to five structural types; complexes 5 and 6 with two previously reported species of the type [Fe2(SR)4] constitute the known examples of three-coordinate FeII with partial or complete sulfur ligation. The zero-field Mössbauer spectra of examples of the five types of homoleptic Fe(II) thiolates are reported together with several tetrahedral complexes having FeII-S/SR coordination in order to determine what structural distinctions could be made from isomer shifts and quadrupole splittings. From the limited data set, it is tentatively concluded that trigonal planar FeII(SR)3 can be distinguished from tetrahedral FeII(SR)4 and FeII-S/SR units on the basis of its smaller quadrupole splitting (0.81 mm/s for 5 at 4.2-100 K).

Original languageEnglish (US)
Pages (from-to)1815-1822
Number of pages8
JournalInorganic Chemistry
Volume34
Issue number7
StatePublished - 1995
Externally publishedYes

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Sulfur
sulfur
Iron
Toluene
iron
Atoms
toluene
synthesis
quadrupoles
Ligands
atoms
ligands
Bond length
Hexanes
linear arrays
Sulfhydryl Compounds
thiols
Isomers
Ether
acetonitrile

ASJC Scopus subject areas

  • Inorganic Chemistry

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Sterically encumbered iron(II) thiolate complexes : Synthesis and structure of trigonal planar [Fe(SR)3]- (R = 2,4,6-t-Bu3C6H2) and Mössbauer spectra of two- and three-coordinate complexes. / MacDonnell, Frederick M.; Ruhlandt, Karin; Ellison, Jeffrey J.; Holm, R. H.; Power, Philip P.

In: Inorganic Chemistry, Vol. 34, No. 7, 1995, p. 1815-1822.

Research output: Contribution to journalArticle

@article{fb19a980928d4480932cae35cdb9d223,
title = "Sterically encumbered iron(II) thiolate complexes: Synthesis and structure of trigonal planar [Fe(SR)3]- (R = 2,4,6-t-Bu3C6H2) and M{\"o}ssbauer spectra of two- and three-coordinate complexes",
abstract = "The synthesis and structural characterization of three compounds containing three-coordinate Fe(II) and stabilized by sterically encumbered thiolate ligands are reported. Reaction of [Fe2(SC6H2-2,4,6-t-Bu3)4] (3) with LiSC6H2-2,4,6-t-Bu3 in ether/THF/hexane afforded [Li(THF)2(5)]·0.5C6H14 (5 = [Fe(SC6H2-2,4,6-t-Bu3)3] -). Addition of Ph4PCl to a reaction mixture in toluene followed by recrystallization of the product from acetonitrile yielded (Ph4P)[5]·2MeCN·C7H8. The compound [Fe3(SC6H2-2,4,6-t-Pr3) 4(N(SiMe3)2)2] was prepared by the reaction of [Fe(N(SiMe3)2)2] (6) with the thiol in toluene. [Li(THF)2(5)]·0.5C6H14 crystallizes in monoclinic space group P21/c with a = 9.809(2) {\AA}, b = 22.507(5) {\AA}, c = 29.553(5) {\AA}, β = 95.72(2)°, and Z = 4 (130 K). (Ph4P)-[5]·2MeCN·C7H8 was obtained in monoclinic space group P21 with a = 17.538(5) {\AA}, b = 14.912(4) {\AA}, c = 17.608(5) {\AA}, β = 115.71(3)°, and Z = 2 (143 K). These compounds contain the first example of mononuclear Fe(II) in a close approach to a trigonal planar [5] or a distorted trigonal planar [Li(THF)2(5)] sulfur coordination environment. In the Ph4P salt, [5] exhibits the mean values Fe-S = 2.274(9) {\AA} and S-Fe-S = 120(3)°, while in [Li(THF)2(S)] the Li+ ion bridges two sulfur atoms, causing a lengthening (0.06-0.07 {\AA}) of the Fe-S bridged bond lengths and constriction of the bridged S-Fe-S angle (92.2(1)°). Compound 6 crystallizes in P21/c with a = 14.521(5) {\AA}, b = 41.60(2) {\AA}, c = 14.241(4) {\AA}, β = 100.42(2)°, and Z = 4 (130 K). The structure has a linear Fe3(μ2-SR)4 fragment with an almost linear Fe3 array involving the central Fe(II) atom in a severely distorted tetrahedral environment; the terminal Fe(II) atoms are three-coordinate and planar with terminal N(SiMe3)2 ligands. Complex 5 expands the family of homoleptic molecular Fe(II) thiolates to five structural types; complexes 5 and 6 with two previously reported species of the type [Fe2(SR)4] constitute the known examples of three-coordinate FeII with partial or complete sulfur ligation. The zero-field M{\"o}ssbauer spectra of examples of the five types of homoleptic Fe(II) thiolates are reported together with several tetrahedral complexes having FeII-S/SR coordination in order to determine what structural distinctions could be made from isomer shifts and quadrupole splittings. From the limited data set, it is tentatively concluded that trigonal planar FeII(SR)3 can be distinguished from tetrahedral FeII(SR)4 and FeII-S/SR units on the basis of its smaller quadrupole splitting (0.81 mm/s for 5 at 4.2-100 K).",
author = "MacDonnell, {Frederick M.} and Karin Ruhlandt and Ellison, {Jeffrey J.} and Holm, {R. H.} and Power, {Philip P.}",
year = "1995",
language = "English (US)",
volume = "34",
pages = "1815--1822",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "7",

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TY - JOUR

T1 - Sterically encumbered iron(II) thiolate complexes

T2 - Synthesis and structure of trigonal planar [Fe(SR)3]- (R = 2,4,6-t-Bu3C6H2) and Mössbauer spectra of two- and three-coordinate complexes

AU - MacDonnell, Frederick M.

AU - Ruhlandt, Karin

AU - Ellison, Jeffrey J.

AU - Holm, R. H.

AU - Power, Philip P.

PY - 1995

Y1 - 1995

N2 - The synthesis and structural characterization of three compounds containing three-coordinate Fe(II) and stabilized by sterically encumbered thiolate ligands are reported. Reaction of [Fe2(SC6H2-2,4,6-t-Bu3)4] (3) with LiSC6H2-2,4,6-t-Bu3 in ether/THF/hexane afforded [Li(THF)2(5)]·0.5C6H14 (5 = [Fe(SC6H2-2,4,6-t-Bu3)3] -). Addition of Ph4PCl to a reaction mixture in toluene followed by recrystallization of the product from acetonitrile yielded (Ph4P)[5]·2MeCN·C7H8. The compound [Fe3(SC6H2-2,4,6-t-Pr3) 4(N(SiMe3)2)2] was prepared by the reaction of [Fe(N(SiMe3)2)2] (6) with the thiol in toluene. [Li(THF)2(5)]·0.5C6H14 crystallizes in monoclinic space group P21/c with a = 9.809(2) Å, b = 22.507(5) Å, c = 29.553(5) Å, β = 95.72(2)°, and Z = 4 (130 K). (Ph4P)-[5]·2MeCN·C7H8 was obtained in monoclinic space group P21 with a = 17.538(5) Å, b = 14.912(4) Å, c = 17.608(5) Å, β = 115.71(3)°, and Z = 2 (143 K). These compounds contain the first example of mononuclear Fe(II) in a close approach to a trigonal planar [5] or a distorted trigonal planar [Li(THF)2(5)] sulfur coordination environment. In the Ph4P salt, [5] exhibits the mean values Fe-S = 2.274(9) Å and S-Fe-S = 120(3)°, while in [Li(THF)2(S)] the Li+ ion bridges two sulfur atoms, causing a lengthening (0.06-0.07 Å) of the Fe-S bridged bond lengths and constriction of the bridged S-Fe-S angle (92.2(1)°). Compound 6 crystallizes in P21/c with a = 14.521(5) Å, b = 41.60(2) Å, c = 14.241(4) Å, β = 100.42(2)°, and Z = 4 (130 K). The structure has a linear Fe3(μ2-SR)4 fragment with an almost linear Fe3 array involving the central Fe(II) atom in a severely distorted tetrahedral environment; the terminal Fe(II) atoms are three-coordinate and planar with terminal N(SiMe3)2 ligands. Complex 5 expands the family of homoleptic molecular Fe(II) thiolates to five structural types; complexes 5 and 6 with two previously reported species of the type [Fe2(SR)4] constitute the known examples of three-coordinate FeII with partial or complete sulfur ligation. The zero-field Mössbauer spectra of examples of the five types of homoleptic Fe(II) thiolates are reported together with several tetrahedral complexes having FeII-S/SR coordination in order to determine what structural distinctions could be made from isomer shifts and quadrupole splittings. From the limited data set, it is tentatively concluded that trigonal planar FeII(SR)3 can be distinguished from tetrahedral FeII(SR)4 and FeII-S/SR units on the basis of its smaller quadrupole splitting (0.81 mm/s for 5 at 4.2-100 K).

AB - The synthesis and structural characterization of three compounds containing three-coordinate Fe(II) and stabilized by sterically encumbered thiolate ligands are reported. Reaction of [Fe2(SC6H2-2,4,6-t-Bu3)4] (3) with LiSC6H2-2,4,6-t-Bu3 in ether/THF/hexane afforded [Li(THF)2(5)]·0.5C6H14 (5 = [Fe(SC6H2-2,4,6-t-Bu3)3] -). Addition of Ph4PCl to a reaction mixture in toluene followed by recrystallization of the product from acetonitrile yielded (Ph4P)[5]·2MeCN·C7H8. The compound [Fe3(SC6H2-2,4,6-t-Pr3) 4(N(SiMe3)2)2] was prepared by the reaction of [Fe(N(SiMe3)2)2] (6) with the thiol in toluene. [Li(THF)2(5)]·0.5C6H14 crystallizes in monoclinic space group P21/c with a = 9.809(2) Å, b = 22.507(5) Å, c = 29.553(5) Å, β = 95.72(2)°, and Z = 4 (130 K). (Ph4P)-[5]·2MeCN·C7H8 was obtained in monoclinic space group P21 with a = 17.538(5) Å, b = 14.912(4) Å, c = 17.608(5) Å, β = 115.71(3)°, and Z = 2 (143 K). These compounds contain the first example of mononuclear Fe(II) in a close approach to a trigonal planar [5] or a distorted trigonal planar [Li(THF)2(5)] sulfur coordination environment. In the Ph4P salt, [5] exhibits the mean values Fe-S = 2.274(9) Å and S-Fe-S = 120(3)°, while in [Li(THF)2(S)] the Li+ ion bridges two sulfur atoms, causing a lengthening (0.06-0.07 Å) of the Fe-S bridged bond lengths and constriction of the bridged S-Fe-S angle (92.2(1)°). Compound 6 crystallizes in P21/c with a = 14.521(5) Å, b = 41.60(2) Å, c = 14.241(4) Å, β = 100.42(2)°, and Z = 4 (130 K). The structure has a linear Fe3(μ2-SR)4 fragment with an almost linear Fe3 array involving the central Fe(II) atom in a severely distorted tetrahedral environment; the terminal Fe(II) atoms are three-coordinate and planar with terminal N(SiMe3)2 ligands. Complex 5 expands the family of homoleptic molecular Fe(II) thiolates to five structural types; complexes 5 and 6 with two previously reported species of the type [Fe2(SR)4] constitute the known examples of three-coordinate FeII with partial or complete sulfur ligation. The zero-field Mössbauer spectra of examples of the five types of homoleptic Fe(II) thiolates are reported together with several tetrahedral complexes having FeII-S/SR coordination in order to determine what structural distinctions could be made from isomer shifts and quadrupole splittings. From the limited data set, it is tentatively concluded that trigonal planar FeII(SR)3 can be distinguished from tetrahedral FeII(SR)4 and FeII-S/SR units on the basis of its smaller quadrupole splitting (0.81 mm/s for 5 at 4.2-100 K).

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