85398 20200117221620.0 doi 10.1039/c8dt03833c sideral 109588 ART-2018-109588 eng Srinivasan, A. Temperature dependence of the spin state and geometry in tricobalt paddlewheel complexes with halide axial ligands 2018 Access copy available to the general public Unrestricted Trinuclear cobalt paddlewheel complexes, [Co-3(dpa)(4)X-2] (dpa = the anion of 2, 2-dipyridylamine, X = Cl-, Br-, -NCS-, -CN-, (NC)(2)N-), are known to demonstrate a thermally-induced spin-crossover (SCO). Despite a wealth of structural and magnetic information about such complexes, the role of the axial ligand on the characteristic SCO temperature (T-1/2) remains ambiguous. The situation is complicated by the observation that the solid state geometry of the complexes, symmetric or unsymmetric, with respect to the central cobalt ion, also appears to influence the SCO behavior. In order to seek trends in the relationship between the nature of the axial ligand, geometry and magnetic properties, we have prepared the first examples of tricobalt paddlewheel complexes with axial fluorido and iodido ligands, as well as two new chlorido and bromido solvates. Their SCO properties are discussed in the context of an examination of previously reported chlorido and bromido adducts. The main conclusions are: (1) T-1/2 values follow the trend I- < Br- approximate to Cl- < F-; (2) while the molecular geometry is predominantly guided by crystal packing for the Cl-, Br- and I- derivatives, the presence of an axial fluoride may favor a more symmetric core; (3) the magnetic characterization of a second example of an unsymmetric complex supports the observation that they display dramatically lower T-1/2 values than their symmetric analogues; and (4) SCO in crystallographically symmetric compounds apparently occurs without loss of molecular or crystallographic symmetry, while a gradual geometric transformation linking the temperature dependence of quasi-symmetric to unsymmetric in crystallographically unconstrained compounds was found. info:eu-repo/grantAgreement/ES/MINECO/MAT2015-68200-C2-1-P info:eu-repo/grantAgreement/EUR/MOLSPIN-COST/CA15128 info:eu-repo/semantics/openAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 4.052 2018 CHEMISTRY, INORGANIC & NUCLEAR 7 / 45 = 0.156 2018 Q1 T1 1.12 2018 Inorganic Chemistry 2018 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Wang, X.P. Clerac, R. Rouzieres, M. (orcid)0000-0002-0444-996X Falvello, L.R. Universidad de Zaragoza McGrady, J.E. Hillard, E.A. 2010 760 Universidad de Zaragoza Dpto. Química Inorgánica Área Química Inorgánica 47, 46 (2018), 16798-16806 Dalton Trans. Dalton Transactions 1477-9226 586803 http://zaguan.unizar.es/record/85398/files/texto_completo.pdf Postprint 508848 http://zaguan.unizar.es/record/85398/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:85398 articulos driver 2020-01-17-21:53:21 ARTICLE