Towards Langmuir-Blodgett films of magnetically interesting materials: solution equilibria in amphiphilic iron(II) complexes of a triazole-containing ligand
Files in This Item:
|Fe_Co_Rdpt_C16anion_Dalton_12Nov09.pdf||1.22 MB||Adobe PDF||Download|
|Title:||Towards Langmuir-Blodgett films of magnetically interesting materials: solution equilibria in amphiphilic iron(II) complexes of a triazole-containing ligand||Authors:||White, Nicholas G.
Feltham, Humphrey L. C.
|Permanent link:||http://hdl.handle.net/10197/3739||Date:||2010||Abstract:||As a first step towards ambiphilic SCO systems where the hydrophobic part of the system is introduced by a non-coordinating anion (i.e. where no modification of the ligands to introduce hydrophobic substituents is required), [FeII(OH2)2(C16SO3)2] and [CoII(OH2)2(C16SO3)2] have been reacted with the triazole-containing ligands adpt and pldpt (C16SO¬3 = hexadecanesulfonate anion, adpt = 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole, pldpt = 4-pyrrolyl-3,5-bis(2-pyridyl)-1,2,4-triazole). In the solid state, HS complexes of the form [FeII(Rdpt)2(C16SO3)2] and [CoII(Rdpt)2(CH3OH)2](C16SO3)2 are observed, even when excess ligand is used (Rdpt = adpt or pldpt). In solution, the cobalt complexes remain in this form as evidenced by colour, Visible/NIR and IR spectroscopy. For the iron complexes, there is an equilibrium in solution between the neutral high-spin form of the complex [FeII(Rdpt)2(C16SO3)2] and the dicationic low-spin form [FeII(Rdpt)3](C16SO3)2. Polar solvents favour the dicationic form, while less polar solvents favour the neutral form (as evidenced by solution colour and solution IR spectroscopy). Visible/NIR spectroscopy and Evans’ method NMR spectroscopy show the equilibrium can be shifted towards the [FeII(Rdpt)3](C16SO3) form by adding additional ligand to the solution. The X-ray crystal structures of [FeII(adpt)2(C16SO3)2] and [CoII(adpt)2(CH3OH)2](C16SO3)2·1.33CH3OH are presented. [FeII(adpt)2(C16SO3)2] has a 2D bilayer structure with alternating layers of polar Fe(adpt)2 centres, and hydrophobic alkyl chains. The complex cations in [CoII(adpt)2(CH3OH)2](C16SO3)2·1.33CH3OH form 1-D columns in the solid state. The capacity of the amphiphilic complexes [FeII(pldpt)2(C16SO3)2] and [FeII(adpt)2(C16SO3)2] to self-assemble has been probed at the air-water interface using Langmuir techniques. The pertinent pressure-area isotherms reveal only a low tendency of the complexes to form films.||Funding Details:||Other funder||Type of material:||Journal Article||Publisher:||RSC Publishing||Copyright (published version):||2010 Royal Society of Chemistry||Keywords:||Iron; Triazoles; Spin crossover; Self assembly||Subject LCSH:||Thin films, Multilayered
|DOI:||10.1039/b923923e||Language:||en||Status of Item:||Peer reviewed|
|Appears in Collections:||Chemistry Research Collection|
Show full item record
This item is available under the Attribution-NonCommercial-NoDerivs 3.0 Ireland. No item may be reproduced for commercial purposes. For other possible restrictions on use please refer to the publisher's URL where this is made available, or to notes contained in the item itself. Other terms may apply.