title: Diamondoid Structure in a Metal-Organic Framework of Fe4 Single-Molecule Magnets.
abstract: A 3D metal-organic framework (MOF) having single-molecule magnet (SMM) linkers was prepared in crystalline form by using a tetrairon(III) complex functionalised with two divergent pyridyl groups, namely [Fe4 (pPy)2 (dpm)6 ] (1; H3 pPy=2-(hydroxymethyl)-2-(pyridin-4-yl)propane-1,3-diol, Hdpm=dipivaloylmethane). Reaction of 1 with silver(I) perchlorate afforded {[Fe4 (pPy)2 (dpm)6 ]2 Ag}ClO4 (2), which crystallises in a cubic face-centred lattice and exhibits two interlocked diamondoid networks. In 2, the SMMs act as linear ditopic synthons, and silver(I) ions as tetrahedral nodes coordinated by four pyridyl nitrogen atoms. The magnetic properties of 1 (S=5 and D≈-0.4 cm(-1) in the ground spin state) are largely preserved in 2, which shows slow magnetic relaxation with an anisotropy barrier of Ueff /kB =11.46(10) K in zero field and 14.25(8) K in an applied field of 1 kOe. However, crystal symmetry triggers highly noncollinear magnetic anisotropy contributions oriented at 109.47° from each other along the threefold axes of AgN4 tetrahedra, a unique scenario fully confirmed by a single-crystal cantilever torque magnetometry investigation. Magnetisation curves down to 0.03 K demonstrated the occurrence of a wide hysteresis loop when the magnetic field was swept along one of the four Ag-N bonds. By symmetry, the crystalline compound can then be persistently magnetised parallel or antiparallel to the four main diagonals of the unit cell, although the crystals have no overall second-order anisotropy.
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia & INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy. luca.rigamonti@unimore.it.
authors.forename: Luca
authors.identifier: http://orcid.org/0000-0002-9875-9765
authors.initials: L
authors.lastname: Rigamonti
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia & INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy.|Department of Chemistry, University of Warwick, Gibbet Hill, Coventry, CV4 7AL, UK.
authors.forename: Carri
authors.initials: C
authors.lastname: Cotton
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia & INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy.|Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, via G. Campi 213/a, 41125, Modena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Nava
authors.affiliation: TU Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Anorganische Chemie, Chemnitz, 09107, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Lang
authors.affiliation: TU Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Anorganische Chemie, Chemnitz, 09107, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Rüffer
authors.affiliation: Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze & INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino (FI), Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Perfetti
authors.affiliation: Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze & INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino (FI), Italy.
authors.forename: Lorenzo
authors.identifier: http://orcid.org/0000-0003-4785-1331
authors.initials: L
authors.lastname: Sorace
authors.affiliation: Laboratoire National des Champs Magnétiques Intenses (LNCMI), CNRS, 25 Avenue des Martyrs, BP 166, 38042, Grenoble CEDEX 9, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Barra
authors.affiliation: Institut Néel, CNRS, 25 Avenue des Martyrs, BP 166, 38042, Grenoble Cedex 9, France.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Lan
authors.affiliation: Institut Néel, CNRS, 25 Avenue des Martyrs, BP 166, 38042, Grenoble Cedex 9, France.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wernsdorfer
authors.affiliation: Laboratory of Molecular Magnetism (LAMM), Dipartimento di Chimica 'Ugo Schiff', Università degli Studi di Firenze & INSTM RU of Firenze, via della Lastruccia 3-13, 50019, Sesto Fiorentino (FI), Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Sessoli
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia & INSTM RU of Modena and Reggio Emilia, via G. Campi 103, 41125, Modena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cornia
keywords: cluster compounds; iron; magnetic properties; metal-organic frameworks; torque magnetometry