Iron(II) Complexes of Dimethyltriazacyclophane

Wei-Tsung Less; Matthias Zeller; David Upp; Yuliya Politanska; Doug Steinman; Talal Al-Assil; Daniel P Becker

doi:10.1107/S2053229618015255

Iron(II) Complexes of Dimethyltriazacyclophane

Wei-Tsung Less, Matthias Zeller, David Upp, Yuliya Politanska, Doug Steinman, Talal Al-Assil, Daniel P Becker

Department of Chemistry and Biochemistry

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

Abstract

Treatment of the ortho -triazacyclophane 1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-triene [(C 6 H 5 ) 3 (NH)(NCH 3 ) 2 , L1 ] with Fe[N(SiMe 3 ) 2 ] 2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C 20 H 18 N 3 ) 4 ] or Fe 2 ( L1 ) 4 ( 9 ). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κ N 7 )bis(tetrahydrofuran-κ O )iron(II), [Fe(C 20 H 18 N 3 ) 2 (C 4 H 8 O) 2 ] or ( L1 ) 2 Fe(THF) 2 ( 10 ). The reaction is reversible and 10 reverts in vacuo to diiron complex 9 . In the structures of both 9 and 10 , the monoanionic triazacyclophane ligand L1 − is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ 3 -coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1 − ligands are bound in either a η 2 -chelating fashion through the amide and one amine donor (for one of the four ligands of 9 ), or solely through their amide N atoms in an even simpler monodentate η 1 -coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long FeFe distance of 2.912&emsp14;(1)&emsp14;Å observed in the solid state.

Original language	American English
Journal	Chemistry: Faculty Publications and Other Works
Volume	C
Issue number	74
DOIs	https://doi.org/10.1107/S2053229618015255
State	Published - Jan 1 2018

Keywords

benzo-fused TACN
diiron complex
ipso interaction
DFT calculation
azacyclophane
crystal structure
computational chemistry

Disciplines

Chemistry

Access to Document

10.1107/S2053229618015255License: Unspecified

Iron(II) Complexes of Di methyl tri aza cyclo phaneFinal published version, 928 KBLicense: Unspecified

Cite this

@article{af0ed0f5a7514eaab08bc665e1556d2d,

title = "Iron(II) Complexes of Dimethyltriazacyclophane",

abstract = " Treatment of the ortho -triazacyclophane 1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-triene [(C 6 H 5 ) 3 (NH)(NCH 3 ) 2 , L1 ] with Fe[N(SiMe 3 ) 2 ] 2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C 20 H 18 N 3 ) 4 ] or Fe 2 ( L1 ) 4 ( 9 ). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κ N 7 )bis(tetrahydrofuran-κ O )iron(II), [Fe(C 20 H 18 N 3 ) 2 (C 4 H 8 O) 2 ] or ( L1 ) 2 Fe(THF) 2 ( 10 ). The reaction is reversible and 10 reverts in vacuo to diiron complex 9 . In the structures of both 9 and 10 , the monoanionic triazacyclophane ligand L1 − is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ 3 -coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1 − ligands are bound in either a η 2 -chelating fashion through the amide and one amine donor (for one of the four ligands of 9 ), or solely through their amide N atoms in an even simpler monodentate η 1 -coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long FeFe distance of 2.912&emsp14;(1)&emsp14;Å observed in the solid state.",

keywords = "benzo-fused TACN, diiron complex, ipso interaction, DFT calculation, azacyclophane, crystal structure, computational chemistry",

author = "Wei-Tsung Less and Matthias Zeller and David Upp and Yuliya Politanska and Doug Steinman and Talal Al-Assil and Becker, {Daniel P}",

year = "2018",

month = jan,

day = "1",

doi = "10.1107/S2053229618015255",

language = "American English",

volume = "C",

journal = "Chemistry: Faculty Publications and Other Works",

number = "74",

}

TY - JOUR

T1 - Iron(II) Complexes of Dimethyltriazacyclophane

AU - Less, Wei-Tsung

AU - Zeller, Matthias

AU - Upp, David

AU - Politanska, Yuliya

AU - Steinman, Doug

AU - Al-Assil, Talal

AU - Becker, Daniel P

PY - 2018/1/1

Y1 - 2018/1/1

N2 - Treatment of the ortho -triazacyclophane 1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-triene [(C 6 H 5 ) 3 (NH)(NCH 3 ) 2 , L1 ] with Fe[N(SiMe 3 ) 2 ] 2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C 20 H 18 N 3 ) 4 ] or Fe 2 ( L1 ) 4 ( 9 ). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κ N 7 )bis(tetrahydrofuran-κ O )iron(II), [Fe(C 20 H 18 N 3 ) 2 (C 4 H 8 O) 2 ] or ( L1 ) 2 Fe(THF) 2 ( 10 ). The reaction is reversible and 10 reverts in vacuo to diiron complex 9 . In the structures of both 9 and 10 , the monoanionic triazacyclophane ligand L1 − is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ 3 -coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1 − ligands are bound in either a η 2 -chelating fashion through the amide and one amine donor (for one of the four ligands of 9 ), or solely through their amide N atoms in an even simpler monodentate η 1 -coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long FeFe distance of 2.912&emsp14;(1)&emsp14;Å observed in the solid state.

AB - Treatment of the ortho -triazacyclophane 1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-triene [(C 6 H 5 ) 3 (NH)(NCH 3 ) 2 , L1 ] with Fe[N(SiMe 3 ) 2 ] 2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C 20 H 18 N 3 ) 4 ] or Fe 2 ( L1 ) 4 ( 9 ). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[ b , e , h ][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κ N 7 )bis(tetrahydrofuran-κ O )iron(II), [Fe(C 20 H 18 N 3 ) 2 (C 4 H 8 O) 2 ] or ( L1 ) 2 Fe(THF) 2 ( 10 ). The reaction is reversible and 10 reverts in vacuo to diiron complex 9 . In the structures of both 9 and 10 , the monoanionic triazacyclophane ligand L1 − is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ 3 -coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1 − ligands are bound in either a η 2 -chelating fashion through the amide and one amine donor (for one of the four ligands of 9 ), or solely through their amide N atoms in an even simpler monodentate η 1 -coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long FeFe distance of 2.912&emsp14;(1)&emsp14;Å observed in the solid state.

KW - benzo-fused TACN

KW - diiron complex

KW - ipso interaction

KW - DFT calculation

KW - azacyclophane

KW - crystal structure

KW - computational chemistry

UR - https://ecommons.luc.edu/chemistry_facpubs/92

U2 - 10.1107/S2053229618015255

DO - 10.1107/S2053229618015255

M3 - Article

VL - C

JO - Chemistry: Faculty Publications and Other Works

JF - Chemistry: Faculty Publications and Other Works

IS - 74

ER -

Iron(II) Complexes of Dimethyltriazacyclophane

Abstract

Keywords

Disciplines

Access to Document

Other files and links

Cite this