White, Nicholas G. Feltham, Humphrey L. C. Gandolfi, Claudio Albrecht, Martin Brooker, Sally 2010-03-02 As a first step towards amphiphilic spin crossover (SCO) systems where the hydrophobic part of the system is introduced by a non-coordinating anion (<i>i.e.</i> where no modification of the ligands to introduce hydrophobic substituents is required), [Fe^II(OH₂)₂(C₁₆SO₃)₂] and [Co^II(OH₂)₂(C₁₆SO₃)₂] have been prepared and reacted with the triazole-containing ligands <strong>adpt</strong> and <strong>pldpt</strong> (C₁₆SO₃ = hexadecanesulfonate anion, <strong>adpt</strong> = 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole, <strong>pldpt</strong> = 4-pyrrolyl-3,5-bis(2-pyridyl)-1,2,4-triazole). In the solid state, two HS complexes of the form [Fe^II(<strong>Rdpt</strong>)₂(C₁₆SO₃)₂] and two of the form [Co^II(<strong>Rdpt</strong>)₂(CH₃OH)₂](C₁₆SO₃)₂ are obtained, even when a six-fold excess of ligand is used (<strong>Rdpt</strong> = <strong>adpt</strong> or <strong>pldpt</strong>). 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 [Fe^II(<strong>Rdpt</strong>)₂(C₁₆SO₃)₂] and the dicationic low-spin <i>tris</i> form [Fe^II(<strong>Rdpt</strong>)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 [Fe^II(<strong>Rdpt</strong>)₃](C₁₆SO₃)₂ form by adding additional ligand to the solution. The X-ray crystal structures of [Fe^II(<strong>adpt</strong>)₂(C₁₆SO₃)₂] and [Co^II(<strong>adpt</strong>)₂(CH₃OH)₂](C₁₆SO₃)₂·1.33CH₃OH are presented. [Fe^II(<strong>adpt</strong>)₂(C₁₆SO₃)₂] has a 2D bilayer structure with alternating layers of polar Fe(<strong>adpt</strong>)₂ centres, and hydrophobic alkyl chains. The complex cations in [Co^II(<strong>adpt</strong>)₂(CH₃OH)₂](C₁₆SO₃)₂·1.33CH₃OH form 1-D columns in the solid state. The capacity of the amphiphilic complexes [Fe^II(<strong>pldpt</strong>)₂(C₁₆SO₃)₂] and [Fe^II(<strong>adpt</strong>)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. application/pdf https://folia.unifr.ch/global/documents/301567 https://folia.unifr.ch/documents/301567/files/gan_tlb.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1039/b923923e info:eu-repo/semantics/openAccess License undefined Dalton Transactions. - 2010, vol. 39, p. 3751-3758 info:eu-repo/classification/udc/54 Towards Langmuir–Blodgett films of magnetically interesting materials: solution equilibria in amphiphilic iron(II) complexes of a triazole-containing ligand http://purl.org/coar/resource_type/c_6501