Crystal Engineering of Multifunctional Molecule-Based Materials – CREMM

Following the identification of the different goals of this project, the work program can be accordingly decomposed into four main tasks:

Task 1: Syntheses of novel magnetic complexes
(i) Toward SMM behaviour (Bucharest)
(ii) Toward MCE behaviour (Bucharest)
(iii) Toward photomagnetic behaviour (Bucharest)
(iv) Toward conducting behaviour: TTF with coordination ability (Angers)

Task 2: Elaboration of conducting materials
(i) With SCO behaviour (Angers)
(ii) With SMM behaviour (Rennes/Angers)

Task 3: Advanced physical properties of the materials
(i) Evaluation of SMM and MCE behaviour (Bordeaux/Bucharest)
(ii) Optical and photomagnetic properties (Bordeaux)
(iii) Association of conductivity with SMM or SCO behaviour (Rennes/Angers)

Task 4: Project coordination and High-Level Classes
(i) Project coordination
(ii) High-Level Classes

On Task 1, the collaboration between Bucarest and Bordeaux concentrated on bimetallic CoII–LnIII systems as well as 2D structures obtained in CoII–FeIII et FeII–CoIII systems with pentadentate ligands. This topic has been recently reviewed (Chem. Soc. Rev. 2016). Besides an original linker [Ru(valen)(CN)2]– has been successfully associated with rare earth cations.

On Task 2, the introduction of spin cross-over or photomagnetic systems concerned a large variety of complexes prepared in Bucarest and investigated in Bordeaux for their magnetic properties, with encouraging results on CoII complexes. Besides, the association of SCO systems through halogen bonding, performed in Rennes, was not successful and has been interrupted.

Task 3 is dedicated to the introduction of counter–ions bringing a metallic conductivity to the system. The group of Angers has accordingly prepared tetrathiafulvalene carboxylates anions, further associated with bimetallic cations prepared in Bucarest. The latter were also associated with dithiolene complexes (Rennes)

This project has demonstrated the outstanding interest of polymetallic complexes with bi- or tricompartimental ligands developed in Bucarest for the elaboration of original multifunctional magnetic systems. The collaboration between the four groups has been strongly strengthened, and has allowed for the start of several new projects.

The project has led to the co-publication of around 10 scientific articles in the best journals (J. Am. Chem. Soc. , Inorg. Chem., Dalton Trans., …). Besides, it has been the occasion to organize in Romania two major events, (i) a School dedicated to Molecular Magnetism, in April 2014 in Bucarest (20h classes for 25 participants), and (ii) a Scientific Symposium during 4 days in May 2016 in Sinaia, with 20 invited and contributed talks, among them J.-M. Lehn (Université de Strasbourg) and three invited speakers not belonging to the ANR project, i.e. Dr. J.-P. Sutter (LCC Toulouse), Pr. M Almeida (University Lisbon) and Dr. D. Luneau (Université de Lyon).

Multi-partner publications:

1. C. Maxim, D. G. Branzea, C. Tiseanu, M. Rouzie`res, R. Cle´rac,, M. Andruh, N. Avarvari
Inorg. Chem. 2014, 53, 2708-2717

2. A. Dogaru, C. Pichon, R. Ababei, D. Mitcov, C. Maxim, L. Toupet, C. Mathonière, R. Clérac, M. Andruh
Polyhedron 2014, 75, 146–152

3. M. Atzori, L. Marchiò, R. Clérac, A. Serpe, P. Deplano, N. Avarvari, M. L. Mercuri
Cryst. Growth Des. 2014, 14, 5938-5948

4. G. Marinescu,; C. Maxim, R. Clérac, M. Andruh
Inorg. Chem. 2015, 54, 5621-5623

5. L. Stoicescu, C. Maxim, M. Rouzières, M. Hillebrand, R. Clérac, M. Andruh
Polyhedron 2015, 92, 111-116

6. A. Dogaru, P. Dechambenoit, S. Shova, M. Andruh,
Rev. Roum. Chim. 2015, 60, 371

7. M. Atzori, F. Pop, P. Auban-Senzier, R. Cle´rac, E. Canadell, M. L. Mercuri et N. Avarvari
Inorg. Chem. 2015, 54, 3643-3653.

8. D. Visinescu, M. G. Alexandru, A. M. Madalan, I.-R. Jeon, C. Mathonière, R. Clérac, M. Andruh,
Dalton Trans. 2016, 45, 7642-7649

9. D. G. Branzea, F. Pop, P. Auban-Senzier, R. Clérac, P. Alemany, E. Canadell, et N. Avarvari
J. Am. Chem. Soc. 2016, 138, 6838-6851.

The current project entitled "Crystal Engineering of Multifunctional Molecule-Based Materials" addresses fundamental issues for the understanding of important questions faced today by researchers in Molecular Magnetism, particularly toward the control and the manipulation of magnetic coupling on the one hand, magnetic anisotropy on the other hand. Their combined role will be particularly investigated here in a variety of coordination complexes developed in Bucharest, which exhibit Single Molecule Magnet (SMM), Single Chain Magnet (SCM), Magneto-Caloric Effect (MCE) or PhotoMagnetic properties, together with their introduction in molecular conductors. Our collaborative consortium associates one research group in Bucharest (M. Andruh), and one research group in Bordeaux (R. Clérac, C. Mathonière), both with a strong experience in molecular magnetism and coordination chemistry of classical (S > ½), anisotropic spins, together with two research groups in Rennes (M. Fourmigué) and Angers (N. Avarvari), with a strong background in molecular conductors and quantum (S = ½) spin systems, and crystal engineering strategies. The Bucharest group is internationally recognized for the preparation of very original magnetic coordination compounds. This project is devoted to adding new functions to these compounds as magnet-like behaviour, photomagnetic or conducting properties. The three French partners offer complementary expertise along these lines to develop these series of complexes designed and prepared in Bucharest.