Spin-transition frameworks based on bistetrazole and triazine ligands Quesada Vilar, Manuel

Spin-transition frameworks based on bistetrazole and triazine ligands

Quesada Vilar, Manuel

Citation

Quesada Vilar, M. (2007, March 29). Spin-transition frameworks based on bistetrazole and

triazine ligands. Retrieved from https://hdl.handle.net/1887/11463

Version: Corrected Publisher’s Version

License: Licence agreement concerning inclusion of doctoral thesis in the

Institutional Repository of the University of Leiden

Downloaded from: https://hdl.handle.net/1887/11463

Note: To cite this publication please use the final published version (if applicable).

2

Spin-Transition Frameworks based on

Bistetrazole and Triazine Ligands

PROEFSCHRIFT

ter verkrijging van de graad van Doctor aan de Universiteit Leiden, op

gezag van de Rector Magnificus prof. mr. P.F. van der Heijden,

volgens besluit van het College voor Promoties te verdedigen op

donderdag 29 maart 2007 klokke 13.45 uur

door

Manuel Quesada Vilar

geboren te Cincinnati, USA in 1978

4

Samenstelling promotiecommissie

Promotor: Prof. Dr. J. Reedijk

Co-promotors: Dr. P. Gamez

Dr. J. G. Haasnoot

Referent: Prof. Dr. L. J. De Jongh

Overige Leden: Prof. Dr. E. Coronado

Dr. P.J. van Koningsbruggen

This work was possible thanks to the CW-NWO and to Magmanet, a Network of

Excellence.

ISBN: 978907867508 2

“Lo último que uno sabe, es por donde empezar.”

Blaise Pascal (1623-1661)

A mis padres y a mi hermano.

6

Contents

Abbreviations 8

Chapter 1 Introduction 9

Chapter 2 Physical techniques and general syntheses. 34 Chapter 3 Effect of substituted alkyl-based spacers on the formation of bistetrazole

spin-transition polymers.

I. [Fe(µ-btzmp)2(btzmp)2](ClO4)2

II. [Fe^II(btzpol)1.8(btzpol-OBF3)1.2](BF4)0.8(H2O)(CH3CN)

54

Chapter 4 Counterion effect on the spin-transition properties of the [Fe(btzx)3]²⁺

cation (btzx = m-xylylene(bis)tetrazole). 81 Chapter 5 Structural considerations on bistetrazole-based spin-transition

compounds.

107

Chapter 6 Coordination dependence of magnetic properties within a family of

related dinuclear [M^II2] complexes of a triazine-based ligand. 127 Chapter 7 Spin-transition studies in a series of triazine-based Fe^II complexes:

variable-temperature structural, thermal, magnetic and spectroscopic studies.

147

Chapter 8 A molecular nanoporous material showing tuneable spin-crossover near

room temperature. 169

Chapter 9 Concluding remarks and perspectives. 187

Samenvatting 197

Summary 201

Resumen 205

Curriculum Vitae 209

List of Publications 210

Acknowledgments 213

8

Abbreviations

SCO, ST Spin Crossover, Spin Transition

LIESST, LITH Light Induced Excited Spin State Trapping, Light Induced Thermal Hysteresis

T½ Transition Temperature

HS, LS ,

γ

HS High Spin, Low Spin, High Spin fraction (

γ

HS = 1-

γ

LS) Dq Cubic ligand Field Splitting

KHL Relaxation Constant (s^-1)

G, H, S Gibbs free energy, enthalpy, entropy (J) NA Avogadro ’s number, 6.022×10²³ (mol^-1)

KB Boltzmann Constant, 1.380658×10^-23JK^-1 (0.69503877 cm^-1 K^-1) β Bohr Magneton, 9.274×10^-24 JT^-1 (4.66864×10^-5 cm^-1 G^-1) g electron gyromagnetic factor (2.002 for a free electron) R gas constant, 8.314472 (J K^-1 mol^-1)

χ, χ

m magnetic susceptibility, molar magnetic susceptibility (cm³ mol^-1) J Isotropic interaction parameter (cm^-1)

D Zero Field Splitting parameter (cm^-1)

TIP Temperature Independent Paramagnetism Cp molar heat capacity at constant pressure (J mol^-1 K^-1) ZFS Zero Field Splitting

∆EQ, IS Quadrupole Splitting and Isomer Shift (mm s^-1) TG Trans-Gauche Conformation

GG Gauche-Gauche Conformation Σ Octahedral Distortion (º) IAP Intrapolymeric Distance (Å) IEP Interpolymeric Distance (Å) Fe-L metal-to-ligand bond length distance (Å) r average value of all Fe−L (Å)

SQUID Superconducting Quantum Interference Device (N)IR near-Infra Red

UV, vis Ultra Violet, Visible

NMR Nuclear Magnetic Resonance DSC Differential Scanning Calorimetry

TGA, DTG Thermal Gravimetric Analysis, Derivative Thermogravimetry ppm parts per million

XRPD, SCXRD X-ray powder diffraction, single crystal x-ray diffraction.

Ligands

ttz tetrazole

btzmp 1,2-bis(tetrazol-1-yl)-1-methylpropane btzpol 1,3-bis(tetrazol-1-yl)-2-propanol btzx m-xylylene(bis)tetrazole

dpyatriz 2,4,6-(dipyridin-2-ylamino)-[1,3,5]-triazine Cl-bdpat 2-chloro[4,6-(dipyridin-2-ylamino)]-[1,3,5]-triazine

(pe-bdpat), ph-bdpat (2-aminopyrene-) 2-phthalimide-4-yl-amino-[4,6-(dipyridin-2- ylamino)]-[1,3,5]-triazine,

amyl, ethyl amyltriazole, ethyltriazole