Redox modulation of field-induced tetrathiafulvalene-based single-molecule magnets of dysprosium S. Tiaouinine, J.F. Gonzalez, V. Montigaud, C.A. Mattei, V. Dorcet, L. Kaboub, V. Cherkasov, O. Cador, Boris Le Guennic, L. Ouahab, et al. To cite this version: S. Tiaouinine, J.F. Gonzalez, V. Montigaud, C.A. Mattei, V. Dorcet, et al.. Redox modulation of field- induced tetrathiafulvalene-based single-molecule magnets of dysprosium. Magnetochemistry, MDPI, 2020, 6 (3), pp.1-13. 10.3390/magnetochemistry6030034. hal-03003315 HAL Id: hal-03003315 https://hal.archives-ouvertes.fr/hal-03003315 Submitted on 13 Nov 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. 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Distributed under a Creative Commons Attribution| 4.0 International License magnetochemistry Article Redox Modulation of Field-Induced Tetrathiafulvalene-Based Single-Molecule Magnets of Dysprosium Siham Tiaouinine 1,2, Jessica Flores Gonzalez 1 , Vincent Montigaud 1, Carlo Andrea Mattei 1 , Vincent Dorcet 1, Lakhmici Kaboub 1, Vladimir Cherkasov 3 , Olivier Cador 1, Boris Le Guennic 1 , Lahcène Ouahab 1, Viacheslav Kuropatov 3,* and Fabrice Pointillart 1,* 1 Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)—UMR 6226, F-35000 Rennes, France; [email protected] (S.T.); jessica.fl[email protected] (J.F.G.); [email protected] (V.M.); [email protected] (C.A.M.); [email protected] (V.D.); [email protected] (L.K.); [email protected] (O.C.); [email protected] (B.L.G.); [email protected] (L.O.) 2 Laboratory of Organic Materials and Heterochemistry, University of Tebessa, Rue de Constantine, 12002 Tébessa, Algeria 3 G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, GSP-445, Tropinina str., 49, 603950 Nizhny Novgorod, Russia; [email protected] * Correspondence: [email protected] (V.K.); [email protected] (F.P.) Received: 8 July 2020; Accepted: 31 July 2020; Published: 19 August 2020 Abstract: The complexes [Dy (tta) (H2SQ)] (Dy-H2SQ) and [Dy (tta) (Q)] 2CH Cl (Dy-Q) (tta 2 6 2 6 · 2 2 − = 2-thenoyltrifluoroacetonate) were obtained from the coordination reaction of the Dy(tta) 2H O 3· 2 units with the 2,20-benzene-1,4-diylbis(6-hydroxy-4,7-di-tert-butyl-1,3-benzodithiol-2-ylium-5-olate ligand (H2SQ) and its oxidized form 2,20-cyclohexa-2,5-diene-1,4-diylidenebis(4,7-di-tert-butyl-1,3- benzodithiole-5,6-dione (Q). The chemical oxidation of H2SQ in Q induced an increase in the coordination number from 7 to 8 around the DyIII ions and by consequence a modulation of the field-induced Single-Molecule Magnet behavior. Computational results rationalized the magnetic properties of each of the dinuclear complexes. Keywords: Dysprosium; tetrathiafulvalene; Redox-Modulation; single molecule magnets; ab initio calculations 1. Introduction One of the most promising routes of research in molecular magnetism is the design of lanthanide coordination complexes [1–4]. Such compounds are able to display magnetic bistability even for mononuclear species [5] due to the intrinsic characteristics of the lanthanide ions [6]. Recently, the observation of memory effects at temperatures close to liquid nitrogen [7–10] led to the revival of the use of such coordination systems for potential applications in high-density data storage [11,12]. Other applications could be targeted such as switches and sensors [13] when the magnetic properties can be modulated by chemical transformations. The modulations of Single-Molecule Magnet (SMM) behavior can be achieved via crystal-to-crystal chemical transformations [14–16], solvato-switching [17–19], isomerization-switching [20–24] or redox-switching [25–27]. Indeed, the magnetic properties of the lanthanide ions can be easily changed by structural transformation since they are very sensitive to the symmetry and electronic distribution of their surroundings [28]. The literature shows that structural changes can be induced by the use of redox active ligands [25–27]. Thus, the combination of Magnetochemistry 2020, 6, 34; doi:10.3390/magnetochemistry6030034 www.mdpi.com/journal/magnetochemistry Magnetochemistry 2020, 6, 34 2 of 13 Magnetochemistry 2020, 6, x FOR PEER REVIEW 2 of 13 lanthanideof lanthanide ions ions and and redox-active redox-active ligands ligands seems seems to beto be a right a right way way to designto design SMM SMM with with modulations modulations of theof th magnetice magnetic behavior. behavior. InIn thethe past,past, some some of of us us already already explored explored this this strategy strategy to design to design redox-active redox-active (chiral) (chiral) SMMs [SMMs29,30] and[29,30] luminescent and luminescent SMMs SMMs [31]. [31]. On On one one hand, hand, the the 4,44,4′,7,7′0,7,70-tetra-tert-butyl-2,2-tetra-tert-butyl-2,2′0-bi-1,3-benzo--bi-1,3-benzo- dithiole-5,5dithiole-5,5′,6,6′0,6,60--tetronetetrone [32] [32] andand 2,22,2′0-benzene-1,4-diylbis(6-hydroxy-4,7-di-tert-butyl-1,3--benzene-1,4-diylbis(6-hydroxy-4,7-di-tert-butyl-1,3- benzodithiol-2-ylium-5-olatebenzodithiol-2-ylium-5-olate [33] [33] ligands (H2SQSQ)) (Scheme 1)1) werewere usedused toto bridgebridge magnetic magnetic lanthanidelanthanide unitsunits [[34,35].34,35]. On the other hand, thethe HH22SQ ligand andand itsits oxidizedoxidized formform 2,22,2′0-cyclohexa--cyclohexa- 2,5-diene-1,4-diylidenebis(4,7-di-tert-butyl-1,3-benzodithiole-5,6-dione2,5-diene-1,4-diylidenebis(4,7-di-tert-butyl-1,3-benzodithiole-5,6-dione ( (QQ)) (Scheme (Scheme 1)1) werewere III III III III associated with with Ln(hfac) Ln(hfac)3 3unitsunits (Ln (Ln = Dy= Dy [36][ and36] andYb Yb[37]) [for37 ])modulating for modulating both magnetic both magnetic and photo and- photo-physicalphysical properties. properties. Scheme 1. Oxidation reaction of the H2SQ ligand in Q ligand with their molecular structures. Scheme 1. Oxidation reaction of the H2SQ ligand in Q ligand with their molecular structures. In the present article, we propose to focus our attention on the H2SQ ligand and its oxidized form In the present article, we propose to focus our attention on the H2SQ ligand and its oxidized Q in the coordination reactions with the Dy(tta)3 2H2O units. The replacement of the hfac− ancillary form Q in the coordination reactions with the ·Dy(tta)3·2H2O units. The replacement of the hfac− anions with tta− is known to change the magnetic performances of the target compound [29,38–40]. ancillary anions with tta− is known to change the magnetic performances of the target compound Indeed, the resulting X-ray structures of the dinuclear complexes [Dy2(tta)6(H2SQ)] (Dy-H2SQ) and [29,38–40]. Indeed, the resulting X-ray structures of the dinuclear complexes [Dy2(tta)III6(H2SQ)] (Dy- [Dy2(tta)6(Q)] 2CH2Cl2 (Dy-Q) highlighted new coordination spheres around the Dy compared to H2SQ) and [Dy· 2(tta)6(Q)]·2CH2Cl2 (Dy-Q) highlighted new coordination spheres around the DyIII those observed for their hfac− parents of formula [Dy2(hfac)6(H2SQ)] CH2Cl2 and [Dy2(hfac)6(Q)]) [36] compared to those observed for their hfac− parents of formula· [Dy2(hfac)6(H2SQ)]·CH2Cl2 and leading to the study of new magnetic properties. Then the modulation of the magnetic properties as [Dy2(hfac)6(Q)]) [36] leading to the study of new magnetic properties. Then the modulation of the consequence of the oxidation of the bridging triads was evaluated. magnetic properties as consequence of the oxidation of the bridging triads was evaluated. 2. Results and Discussion 2. Results and Discussion 2.1. X-ray Structures 2.1. X-ray Structures The coordination reaction of the 2,20-benzene-1,4-diylbis(6-hydroxy-4,7-di-tert-butyl-1,3- benzodithiol-2-ylium-5-olateThe coordination reaction of triad the 2,2′ (H-benzene2SQ)-1,4- (Schemediylbis(61-)hydroxy and-4,7-di-tert tris(2--butyl-1,3- III thenoyltrifluoroacetonate)bis(aqueous)Lnbenzodithiol-2-ylium-5-olate triad (Dy(tta)(H2SQ)3 2H2O)(Scheme in CH 2Cl2 1)led toand the formationtris(2- III · ofthenoy the complexltrifluoroacetonate)bis(aqueous)Ln [Dy2(tta)6(H2SQ)] (Dy-H2SQ (Dy(tta)). Prior3·2H oxidation2O) in CH of H2Cl2SQ2 ledinto to Qtheusing formation an excess of the of MnOcomplex, followed [Dy2(tta) by6(H coordination2SQ)] (Dy-H2SQ reaction). Prior with oxidation Dy(tta) of2H H2SQOled into to Q the using [Dy an(tta) excess(Q)] of2CH MnOCl2, 2 3· 2 2 6 · 2 2 (followedDy-Q) complex. by coordination reaction with Dy(tta)3·2H2O led to the [Dy2(tta)6(Q)]·2CH2Cl2 (Dy-Q) complex.[Dy2 (tta)6(H2SQ)] (Dy-H2SQ). Dy-H2SQ crystallized in the monoclinic space group C2/c (Figure1 and Figure[Dy2(tta) S1,6(H Table2SQ)] S1). (Dy- TheH2SQ asymmetric). Dy-H2SQ unit crystallized is composed in the by monoclinic one half ofspace the group [Dy2(tta) C2/c6(H (Figure2SQ)] dinuclear1 and Figure specie. S1, Table Each S1). of theThe two asymmetric terminal unit coordination is composed sites by are one occupied half of the by one[Dy2 Ln(tta)(tta)6(H32SQunit.)] Thedinuclear coordination specie. Each takes of place the two through terminal the C-Ocoordination− group whilesites are the occupied C-OH group by one remains Ln(tta) free.3 unit.