• Jayaratna, Naleen B.
• Lewis, Justin Cody
• Xie, Ming
• Arachchilage, Harshani J.
• Xue, Jia
• Nadir, Shamila
• Norman, Richard E.

Abstract

<jats:sec><jats:title>Abstract</jats:title><jats:p>[Fe(TPA)Cl<jats:sub>2</jats:sub>](ClO<jats:sub>4</jats:sub>), where TPA is tris-(2-pyridylmethyl)amine, crystallizes in the orthorhombic space group P2<jats:sub>1</jats:sub>2<jats:sub>1</jats:sub>2<jats:sub>1</jats:sub> with Z = 4, a = 8.6264(10) Å, b = 15.459(3) Å, and c = 16.008(3) Å. The structure was determined at 110 K from 4333 reflections (3520 observed) with R = 0.041 (R<jats:sub>w</jats:sub> = 0.082). The iron is pseudo-octahedral with the two chloride ions <jats:italic>cis</jats:italic>. The Fe-Cl bond <jats:italic>trans</jats:italic> to the tertiary amine is shorter. [{Fe(TPA)Cl}<jats:sub>2</jats:sub>O](ClO<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> exhibits two polymorphic monoclinic forms, and the monohydrate also crystallizes in a monoclinic form. For the P2<jats:sub>1</jats:sub>/c polymorph, Z = 2, a = 10.839(2) Å, b = 15.956(3) Å, c = 12.416(2) Å, β = 107.024(10)°, and the structure was determined at 95 K from 6514 reflections (3974 observed) with R = 0.052 (R<jats:sub>w</jats:sub> = 0.099). For the C2/c polymorph, Z = 4, a = 20.5023(17) Å, b = 15.2711(13) Å, c = 16.1069(11) Å, β = 124.465(4)°, and the structure was determined at 161 K from 6250 reflections (3130 observed) with R = 0.0632 (R<jats:sub>w</jats:sub> = 0.1229). For the hydrate, P2<jats:sub>1</jats:sub>/n, Z = 4, a = 16.201(2) Å, b = 16.980(3), c = 16.451(3), β = 112.234(5)°, and the structure was determined at 100 K from 12,745 reflections (6600 observed) with R = 0.097 (R<jats:sub>w</jats:sub> = 0.190). In each of the [{Fe(TPA)Cl}<jats:sub>2</jats:sub>O]<jats:sup>2+</jats:sup> units, each iron is pseudo-octahedral with the chloride and oxide ions <jats:italic>cis</jats:italic>. The oxide bridge is linear, and the two chlorides are <jats:italic>anti</jats:italic>. The Fe-N distance for the pyridyl ring <jats:italic>trans</jats:italic> to the oxide bridge is quite long due to the <jats:italic>trans</jats:italic> influence of the oxide.</jats:p></jats:sec><jats:sec><jats:title>Graphic Abstract</jats:title><jats:p>The X-ray structures of [Fe(TPA)Cl<jats:sub>2</jats:sub>](ClO<jats:sub>4</jats:sub>), where TPA is tris-(2-pyridylmethyl)amine, and three polymorphs of dimeric [{Fe(TPA)Cl}<jats:sub>2</jats:sub>O](ClO<jats:sub>4</jats:sub>)<jats:sub>2</jats:sub> are presented and discussed. </jats:p></jats:sec>

Topics

• impedance spectroscopy
• iron
• size-exclusion chromatography
• amine
• chemical ionisation
• space group