Communication Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX
pubs.acs.org/IC
Lanthanide Tetranuclear Cage and Mononuclear Cocrystalline Nitronyl Nitroxide Complex with Single-Molecule-Magnet Behavior Peng Yun Chen,†,‡ Ming Ze Wu,†,‡ Ting Li,†,‡ Xiu Juan Shi,†,‡ Li Tian,*,†,‡ and Zhong Yi Liu*,†,‡ †
Tianjin Key Laboratory of Structure and Performance for Functional Molecules, ‡Key Laboratory of Inorganic−Organic Hybrid Functional Materials Chemistry, Ministry of Education, College of Chemistry, Tianjin Normal University, Tianjin 300387, P. R. China
Downloaded via UNIV OF NEW ENGLAND on September 27, 2018 at 21:03:24 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
S Supporting Information *
comparatively rare because of the difficulty in furthering magnetic coupling between the orbital of the bridging ligand and the 4f orbital of the LnIII ions. Recently, 4f complexes containing organic radicals have attracted a lot of interest because many of these 4f complexes have been observed to display SMM behavior, owing to the Ising anisotropy of the 4f ions and the strong magnetic coupling interaction between the 4f ions and organic radicals.13,58−63 Long and his colleagues demonstrated that the radical-bridged dinuclear LnIII systems have contributed a few of the best SMMs, with the highest blocking temperature of 20 K.64−67 Although the radical ligand is impactful for engendering an intensive direct-exchange interaction with the free single electrons of the 4f ion, control of more than two of the polynuclear clusters employing this highly reactive unit is extraordinarily challenging. The radical ligand with substitution of a thiophene ring coordinated with rare-earth metal seems to easily give singlechain magnets (SCMs). Until now, only two one-dimensional radical-lanthanide chains ([Dy(hfac)3(NITThienPh)]n and [Tb3(hfac)9(NIT-2thien)3]n) containing a thiophene ring have been reported,68,69 and both of them exhibit magnetic blocking. Motivated to obtain high-performance SCMs, we choose the benzothiophene radical (NITPhThio) as the ligand to react with Dy(hfac)3. Although we did not obtain the expected single-chain compound, the most fascinating thing is that we synthesized the first tetranuclear cage and mononuclear mixed DyIII-radical complex [Dy4(hfac)8(IMPhThio)2(OH)4][Dy(hfac)3(NITPhThio)2] (2) based on the mononuclear [Dy(hfac)3(NITPhThio)2] (1) and Dy(hfac)3·2H2O [hfac = hexafluoroacetylacetone; NITPhThio = (2-(benzo[d]thiophen2-yl)-4,4,5,5-tetramethylimidazolin-1-oxyl-3-oxide; IMPhThio = 2-(benzo[d]thiophen-2-yl)-4,4,5,5-tetramethylimidazolin-1oxyl; Scheme 1]. Complex 1 is a trispin complex that contains a central DyIII ion and two terminal NITPhThio ligands; it exhibits paramagnetic character above 2 K. Complex 2 shows a field-induced slow relaxation of magnetization behavior. The structure conversion from mononuclear 1 to polymeric cage 2 and the magnetic transformation from paramagnetic 1 to SMM 2 demonstrate effective ways to obtain novel molecular-based magnetic materials. Evaporation of the filtrate obtained by adding the CH2Cl2 solution of NITPhThio to the n-heptane solution of Dy(hfac)3· 2H2O formed dark-blue crystals of complex 1. The reaction of 1
ABSTRACT: The first tetranuclear metallacage and mononuclear cocrystalline DyIII-radical complex was synthesized and characterized. The metallacage in [Dy4(hfac)8(IMPhThio)2(OH)4][Dy(hfac)3(NITPhThio)2] consists of Dy(hfac)2+ groups bridged by OH− and the IMPhThio radical. Field-induced single-molecule-magnet behavior was observed in the nitronyl nitroxide radical-bridged polynuclear complex.
R
ecently, the research on polynuclear transition-metal and lanthanide clusters has attracted much attention, owing to the aesthetically novel structures that some complexes exhibit1−4 the latent applications in catalysis,5,6 magnetic materials7−10 and the luminescent materials.11,12 In particular, the most successful achievement in this area was the discovery of single-molecule magnets (SMMs), which exhibit slow magnetic relaxation behavior at the cryogenic temperature. Since the seminal discovery of SMM behavior in the transition-metal cluster Mn12Ac,7 polymetallic clusters containing transitionmetal ions were mainly being investigated for SMM behavior,11,13,14 and very recently 3d/4f heterometallic complexes15−19 and, subsequently, pure 4f complexes10−25 have been regarded as more appropriate for constructing SMMs. The incentive for mixing 3d and 4f ions into a single-molecule aggregate is to obtain high ground-state spin via the introduction of 3d ions and, at the same time, to achieve a large magnetic anisotropy by the inclusion of 4f ions, whereas a distinct advantage of the 4f-based SMMs is that they can achieve the goal of high-performance SMMS, owing to the large unquenched orbital angular momentum in the ground state and the related huge Ising-type magnetic anisotropy.26 The two parameters are the key factors in engendering much higher effective energy barriers. Ishikawa and his colleagues reported the first SMMs based on the lanthanide ion in 2003, which opened a new chapter in modern magnetism.20 Among the lanthanide metal ions, the DyIII ion has undoubtedly given the largest quantity of pure 4f SMMs, owing to the intrinsic large magnetic moment with a Kramers doublet ground state of 6H15/2 and the strong Ising-type magnetic anisotropy.12 Until now, various mononuclear, 26−33 dinuclear, 34−39 trinuclear, 40−42 tetranuclear,37,43−47 and polynuclear48−56 dysprosium-based SMMs have been reported, among which the highest effective energy barrier of a Dy5 pyramid cluster was up to 528 K.57 However, polynuclear SMMs based on pure lanthanide metal ions are © XXXX American Chemical Society
Received: July 10, 2018
A
DOI: 10.1021/acs.inorgchem.8b01923 Inorg. Chem. XXXX, XXX, XXX−XXX
Communication
Inorganic Chemistry
tetrahedron, looking like two caps of the cage (Figure S6). This is the first example for LnIII-radical systems with the tetrahedron cage configuration. Another interesting phenomenon is that the redox reaction involved the reduction of the radical NITPhThio to the radical IMPhThio (Figure S6). This phenomena has been reported in transition-metal-radical complexes71−74 but has never been reported in LnIII-radical systems. At present, the mechanistic details of the deoxygenation pathway are uncertain, and it is predicted that the presence of n-heptane and Dy(hfac)3· 2H2O catalyzes the deoxygenation process. On the basis of refs 71−74, C2H5OH, Cu2+, Co2+, and Mn2+ can also catalyze the deoxygenation process. The temperature dependence of the magnetic susceptibilities for 1 is studied and exhibited in Figure S7. The observed roomtemperature χMT value is 15.06 cm3·K·mol−1, which is close to the calculated values of 14.92 cm3·K·mol−1 for an uncoupled system of one DyIII ion and two radicals. with a decrease of the temperature, the χMT value of 1 almost remains constant until 90 K and then decreases rapidly to a minimum of 10.66 cm3·K· mol−1 at 2.0 K. The data in the range of 2−300 K obey the Curie−Weiss law [χM = C/(T − θ)], with C = 15.14 cm3·K· mol−1 and θ = −1.97 K. Complex 2 exhibits a room-temperature χMT value of 71.45 cm3·K·mol−1, somewhat lower than the theoretical value of 72.30 cm3·K·mol−1 for five magnetically isolated DyIII ions (6H15/2 and g = 4/3) and four NO radicals (S = 1 /2 and g = 2) (Figure S7). Upon cooling, the χMT value decreases slowly until 12 K and then decays rapidly to a minimum of 51.24 cm3·K·mol−1 at 2 K. The decrease of the χMT value in the high-temperature region can be attributed to depopulation of the LnIII MJ states and/or antiferromagnetic coupling between spin carriers. In the whole temperature range, the 1/χM versus T curve follows the Curie−Weiss law with Curie constant C = 71.33 cm3·K·mol−1 and Weiss constant θ = −1.88 K. The alternating-current (ac) susceptibility measurement was measured under a 0 or 5000 Oe direct-current (dc) field with different frequencies to probe the dynamic magnetic behaviors for both 1 and 2. Complex 1 displays a paramagnetic property (Figures S8 and S9), thus indicating no obvious slow relaxation of magnetization behavior. For complex 2, the out-of-phase susceptibility shows obvious frequency-dependent signals (Figure S11), but the maxima for χ″ are not found under zero dc field. The dynamic behavior for 2 suggests that the magnetization relaxation process may be very fast because of the quantum tunneling mechanical process in lanthanide SMMs within the lowest energy doublet. It is generally known that the use of a static magnetic field always effectively suppresses the QTM. Thus, a dc field of 5000 Oe was exerted to explore the ac magnetic susceptibility for complex 2; both temperature and frequency dependencies of the ac susceptibility were carried out, and well-resolved peaks emerged for the out-of-phase signals (Figures 1 and S12). On the basis of the temperature-dependent signals, the relaxation process obeys the Arrhenius law τ = τ0 exp(Ueff/kBT), where τ0 is a preexponential factor, τ−1 = 2πν (ν is extracted from the peak frequency of χ″), and Ueff is the effective anisotropy energy barrier. The plot of ln τ versus T−1 shows a linear dependence (Figure S13), which indicates that the relaxation process follows a thermally activated Orbach mechanism with an energy gap Ueff/kB of 32 K and a preexponential τ0 of 2.96 × 10−9 s, which falls in the range of SMMs.58−69 On the basis of the frequency dependencies of the ac susceptibility measurements, Cole−Cole plots in the form of χ′′ versus χ′ with approximate semicircular shapes have been
Scheme 1. Synthetic Route for Complexes 1 and 2
with equimolar [Dy(hfac)3·2H2O] in heptane/dichloromethane gave crystals of 2. Both of the compounds were characterized by single-crystal X-ray diffraction analyses (Table S1). Complex 1 crystallizes in the monoclinic P21/c space group with Z = 4, and it has a structure very similar to those of the reported terbium or gadolinium complexes.70 In 1, each [Dy(hfac)3(NITPhThio)2] unit shows a mononuclear trispin structure, with the central DyIII ion existing in a DyO8 coordination sphere. As depicted in Scheme 1 and Figure S3, the DyIII ion is surrounded by two NO groups from two NITPhThio radical ligands and three bischelate hfac−. The two Dy−Orad bond lengths are 2.346(3) and 2.361(3) Å, respectively, and the Dy−O(hfac) distances range from 2.336(2) to 2.386(3) Å. The N−O bond lengths in 1 [1.305(4) and 1.308(4) Å] are close to the typical bond lengths in the free nitronyl nitroxides.68,69 When the D2d symmetry is applied to the central ions, the CSM method gives the minimum offset value from the ideal model with S = 0.094 (Figure S3 and Table S2). The molecular structure of 2 belongs to the triclinic P1̅ space group and consists of one mononuclear [DyO8] motif and a tetranuclear [Dy4O4] cage, and all of the five DyIII ions are eight-coordinated and display a distorted triangular dodecahedron geometry (Figure S5 and Table S2). The coordination environments of Dy1, Dy2, Dy3, and Dy4 are basically the same; Dy1 as an example is described in detail. The Dy1 center is coordinated by two bischelate hfac− anions, one μ2-NO (O1) group from the radical ligand, and three μ3-OH− (O19, O20, and O21) bridges. Although Dy5 has a different coordination environment from the above four DyIII centers, it has the same coordination environment as the DyIII ions in complex 1. In 2, the Dy−O(hfac) distances range from 2.291(8) to 2.398(8) Å, the Dy−Orad bond lengths are in the range of 2.404(7)− 2.467(6) Å, and the four μ3-OH− groups connect to the DyIII ions at four vertices, with the Dy−O bond distances ranging from 2.315(8) to 2.390(7) Å. The two N−O bond lengths in 2 [1.378(13) and 1.384(12) Å] are a little longer than that in 1, which is consistent with the literature.71 The prominent structural feature in 2 is the tetranuclear cage [Dy4O4] core, which exists as a tetrahedron configuration connected by four μ3-OH− anions (Figure S6). At the same time, every radical oxygen atom (O1 and O2) coordinates to two DyIII ions of the B
DOI: 10.1021/acs.inorgchem.8b01923 Inorg. Chem. XXXX, XXX, XXX−XXX
Inorganic Chemistry
■
achieved (Figure S13). The data have been fitted on the generalized Debye model, and the distribution coefficient α value has been 0.50−0.15 (between 2 and 4 K). Compared to the mononuclear complex 1, the spin dynamics of the polynuclear metallacage 2 have been improved obviously. This result is associated with the different structual features. For complex 2, the radical oxygen atoms (O1 and O2) as bridges in the tetrahedron cage increase the magnetic interactions of the spin carries. The magnetic coupling resulting from radical bridges typically improves the SMM behavior.75 In conclusion, the first tetranuclear metallacage and mononuclear cocrystalline lanthanide-radical complex 2 is reported. Field-induced SMM behavior was discovered in the radical-bridged polynuclear complex 2. The successful synthesis of this metallacage compound illustrates the possibility of the constructing higher-nuclearity 4f complexes with superior SMM properties by a novel construction strategy using perfomed LnNit complexes as metalloligands.
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.8b01923. Detailed experimental procedures, crystallographic data, and additional structural and magnetic data for complexes 1 and 2 (PDF) Accession Codes
CCDC 1843735−1843736 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
[email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
■
REFERENCES
(1) Bürgstein, M. R.; Gamer, M. T.; Roesky, P. W. Nitrophenolate as a building block for lanthanide chains, layers, and clusters. J. Am. Chem. Soc. 2004, 126, 5213−5218. (2) Kong, X. J.; Wu, Y.; Long, L. S.; Zheng, L. S.; Zheng, Z. A Chiral 60-Metal Sodalite Cage Featuring 24 Vertex-Sharing [Er4(mu3-OH)4] Cubanes. J. Am. Chem. Soc. 2009, 131, 6918−6919. (3) Malaestean, I. L.; Ellern, A.; Baca, S.; Kogerler, P. Cerium oxide nanoclusters: commensurate with concepts of polyoxometalate chemistry? Chem. Commun. 2012, 48, 1499−1501. (4) Wang, R.; Zheng, Z.; Jin, T.; Staples, R. J. Coordination chemistry of lanthanides at ″high″ pH: Synthesis and structure of the pentadecanuclear complex of europium(III) with tyrosine. Angew. Chem., Int. Ed. 1999, 38, 1813−1815. (5) Pohlki, F.; Doye, S. The catalytic hydroamination of alkynes. Chem. Soc. Rev. 2003, 32, 104−114. (6) Edelmann, F. T. Lanthanide amidinates and guanidinates: from laboratory curiosities to efficient homogeneous catalysts and precursors for rare-earth oxide thin films. Chem. Soc. Rev. 2009, 38, 2253−2268. (7) Sessoli, R.; Gatteschi, D.; Caneschi, A.; Novak, M. A. Magnetic bistability in a metal-ion cluster. Nature 1993, 365, 141−143. (8) Romanelli, M.; Kumar, G. A.; Emge, T. J.; Riman, R. E.; Brennan, J. G. Intense near-IR emission from nanoscale lanthanoid fluoride clusters. Angew. Chem., Int. Ed. 2008, 47, 6049−6051. (9) Wang, R.; Song, D.; Wang, S. Toward constructing nanoscale hydroxo-lanthanide clusters: syntheses and characterizations of novel tetradecanuclear hydroxo-lanthanide clusters. Chem. Commun. 2002, 37, 368−369. (10) Eliseeva, S. V.; Bünzli, J. C. G. Lanthanide luminescence for functional materials and bio-sciences. Chem. Soc. Rev. 2010, 39, 189− 227. (11) Sorace, L.; Benelli, C.; Gatteschi, D. Lanthanides in molecular magnetism: old tools in a new field. Chem. Soc. Rev. 2011, 40, 3092− 3104. (12) Woodruff, D. N.; Winpenny, R. E. P.; Layfield, R. A. SingleMolecule Magnetism in Tetrametallic Terbium and Dysprosium Thiolate Cages. Chem. Rev. 2013, 113, 5110−5148. (13) Poneti, G.; Bernot, K.; Bogani, L.; Caneschi, A.; Sessoli, R.; Wernsdorfer, W.; Gatteschi, D. A rational approach to the modulation of the dynamics of the magnetisation in a dysprosium-nitronylnitroxide radical complex. Chem. Commun. 2007, 43, 1807−1809. (14) Lin, P. H.; Burchell, T. J.; Ungur, L.; Chibotaru, L. F.; Wernsdorfer, W.; Murugesu, M. A Polynuclear Lanthanide SingleMolecule Magnet with a Record Anisotropic Barrier. Angew. Chem., Int. Ed. 2009, 48, 9489−9492. (15) Osa, S.; Kido, T.; Matsumoto, N.; Re, N.; Pochaba, A.; Mrozinski, J. A tetranuclear 3d-4f single molecule magnet: [(CuLTbIII)LII(hfac)2]2. J. Am. Chem. Soc. 2004, 126, 420−421. (16) Mishra, A.; Wernsdorfer, W.; Abboud, K. A.; Christou, G. Initial observation of magnetization hysteresis and quantum tunneling in mixed manganese-Lanthanide single-molecule magnets. J. Am. Chem. Soc. 2004, 126, 15648−15649. (17) Cao, F.; Wang, S.; Li, D.; Zeng, S.; Niu, M.; Song, Y.; Dou, J. Family of mixed 3d-4f dimeric 14-metallacrown-5 compounds: syntheses, structures, and magnetic properties. Inorg. Chem. 2013, 52, 10747−10755. (18) Langley, S. K.; Wielechowski, D. P.; Vieru, V.; Chilton, N. F.; Moubaraki, B.; Chibotaru, L. F.; Murray, K. S. The first 4d/4f singlemolecule magnet containing a {(Ru2Dy2III)DyIII} core. Chem. Commun. 2015, 51, 2044−2047. (19) Li, M.; Lan, Y.; Ako, A. M.; Wernsdorfer, W.; Anson, C. E.; Buth, G.; Powell, A. K.; Wang, Z.; Gao, S. A Family of 3d-4f Octa-Nuclear [Mn4IIILn4III] Wheels (Ln = Sm, Gd, Tb, Dy, Ho, Er, and Y): Synthesis, Structure, and Magnetism. Inorg. Chem. 2010, 49, 11587−11594. (20) Ishikawa, N.; Sugita, M.; Ishikawa, T.; Koshihara, S. Y.; Kaizu, Y. Lanthanide double-decker complexes functioning as magnets at the single-molecular level. J. Am. Chem. Soc. 2003, 125, 8694−8695. (21) Hewitt, I. J.; Tang, J.; Madhu, N. T.; Anson, C. E.; Lan, Y.; Luzon, J.; Etienne, M.; Sessoli, R.; Powell, A. K. Coupling Dy-3 Triangles
Figure 1. Temperature dependence of the in-phase (left) and out-ofphase (right) components of the ac magnetic susceptibility for complex 2 under a 5000 Oe dc field.
■
Communication
AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected] (L.T.). *E-mail:
[email protected] (Z.Y.L.). ORCID
Li Tian: 0000-0003-1121-8331 Notes
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS This work was financially supported by the National Natural Science Foundation of China (Grant 21371133). C
DOI: 10.1021/acs.inorgchem.8b01923 Inorg. Chem. XXXX, XXX, XXX−XXX
Communication
Inorganic Chemistry Enhances Their Slow Magnetic Relaxation. Angew. Chem., Int. Ed. 2010, 49, 6352−6356. (22) Jiang, S. D.; Wang, B. W.; Sun, H. L.; Wang, Z. M.; Gao, S. An Organometallic Single-Ion Magnet. J. Am. Chem. Soc. 2011, 133, 4730− 4733. (23) Vincent, R.; Klyatskaya, S.; Ruben, M.; Wernsdorfer, W.; Balestro, F. Electronic read-out of a single nuclear spin using a molecular spin transistor. Nature 2012, 488, 357−360. (24) Blagg, R. J.; Ungur, L.; Tuna, F.; Speak, J.; Comar, P.; Collison, D.; Wernsdorfer, W.; McInnes, E. J. L.; Chibotaru, L. F.; Winpenny, R. E. P. Magnetic relaxation pathways in lanthanide single-molecule magnets. Nat. Chem. 2013, 5, 673−678. (25) Thiele, S.; Balestro, F.; Ballou, R.; Klyatskaya, S.; Ruben, M.; Wernsdorfer, W. Electrically driven nuclear spin resonance in singlemolecule magnets. Science 2014, 344, 1135−1138. (26) Chen, Y. C.; Liu, J. L.; Ungur, L.; Liu, J.; Li, Q. W.; Wang, L. F.; Ni, Z. P.; Chibotaru, L. F.; Chen, X. M.; Tong, M. L. SymmetrySupported Magnetic Blocking at 20 K in Pentagonal Bipyramidal Dy(III) Single-Ion Magnets. J. Am. Chem. Soc. 2016, 138, 2829−2837. (27) Aldamen, M. A.; Clemente-Juan, J. M.; Coronado, E.; MartiGastaldo, C.; Gaita-Arino, A. Mononuclear lanthanide single-molecule magnets based on polyoxometalates. J. Am. Chem. Soc. 2008, 130, 8874−8875. (28) Aravena, D.; Ruiz, E. Shedding light on the single-molecule magnet behavior of mononuclear DyIII complexes. Inorg. Chem. 2013, 52, 13770−13778. (29) Zhang, P.; Zhang, L.; Wang, C.; Xue, S.; Lin, S. Y.; Tang, J. Equatorially coordinated lanthanide single ion magnets. J. Am. Chem. Soc. 2014, 136, 4484−4487. (30) Ungur, L.; Le Roy, J. J.; Korobkov, I.; Murugesu, M.; Chibotaru, L. F. Fine-tuning the local symmetry to attain record blocking temperature and magnetic remanence in a single-ion magnet. Angew. Chem., Int. Ed. 2014, 53, 4413−4417. (31) Upadhyay, A.; Singh, S. K.; Das, C.; Mondol, R.; Langley, S. K.; Murray, K. S.; Rajaraman, G.; Shanmugam, M. Enhancing the effective energy barrier of a Dy(III) SMM using a bridged diamagnetic Zn(II) ion. Chem. Commun. 2014, 50, 8838−8841. (32) Zhu, J.; Wang, C.; Luan, F.; Liu, T.; Yan, P.; Li, G. Local coordination geometry perturbed beta-diketone dysprosium single-ion magnets. Inorg. Chem. 2014, 53, 8895−8901. (33) Liu, J.; Chen, Y. C.; Liu, J. L.; Vieru, V.; Ungur, L.; Jia, J. H.; Chibotaru, L. F.; Lan, Y. H.; Wernsdorfer, W.; Gao, S.; Chen, X. M.; Tong, M. L. A Stable Pentagonal Bipyramidal Dy(III) Single-Ion Magnet with a Record Magnetization Reversal Barrier over 1000 K. J. Am. Chem. Soc. 2016, 138, 5441−5450. (34) Guo, Y. N.; Xu, G. F.; Wernsdorfer, W.; Ungur, L.; Guo, Y.; Tang, J. K.; Zhang, H. J.; Chibotaru, L. F.; Powell, A. K. Strong Axiality and Ising Exchange Interaction Suppress Zero-Field Tunneling of Magnetization of an Asymmetric Dy2 Single-Molecule Magnet. J. Am. Chem. Soc. 2011, 133, 11948−11951. (35) Zhang, P.; Zhang, L.; Lin, S. Y.; Xue, S.; Tang, J. K. Modulating Magnetic Dynamics of Dy2 System through the Coordination Geometry and Magnetic Interaction. Inorg. Chem. 2013, 52, 4587− 4592. (36) Katoh, K.; Asano, R.; Miura, A.; Horii, Y.; Morita, T.; Breedlove, B. K.; Yamashita, M. Effect of f-f interactions on quantum tunnelling of the magnetization: mono- and dinuclear Dy(III) phthalocyaninato triple-decker single-molecule magnets with the same octacoordination environment. Dalton Trans 2014, 43, 7716−7725. (37) Zhang, X. J.; Vieru, V.; Feng, X. W.; Liu, J. L.; Zhang, Z. J.; Na, B.; Shi, W.; Wang, B. W.; Powell, A. K.; Chibotaru, L. F.; Gao, S.; Cheng, P.; Long, J. R. Influence of Guest Exchange on the Magnetization Dynamics of Dilanthanide Single-Molecule-Magnet Nodes within a Metal-Organic Framework. Angew. Chem., Int. Ed. 2015, 54, 9861− 9865. (38) Huang, W.; Shen, F. X.; Wu, S. Q.; Liu, L.; Wu, D. Y.; Zheng, Z.; Xu, J.; Zhang, M.; Huang, X. C.; Jiang, J.; Pan, F. F.; Li, Y.; Zhu, K.; Sato, O. Metallogrid single-molecule magnet: solvent-induced nuclearity
transformation and magnetic hysteresis at 16 K. Inorg. Chem. 2016, 55, 5476−5484. (39) Wang, W. M.; Wang, S. Y.; Zhang, H. X.; Shen, H. Y.; Zou, J. Y.; Gao, H. L.; Cui, J. Z.; Zhao, B. Modulating single-molecule magnet behaviour of phenoxo-O bridged lanthanide(III) dinuclear complexes by using different β-diketonate coligands. Inorg. Chem. Front. 2016, 3, 133−141. (40) Tang, J. H. I.; Hewitt, I.; Madhu, N. T.; Chastanet, G.; Wernsdorfer, W.; Anson, C. E.; Benelli, C.; Sessoli, R.; Powell, A. K. Dysprosium triangles showing single-molecule magnet behavior of thermally excited spin states. Angew. Chem., Int. Ed. 2006, 45, 1729− 1733. (41) Andrews, P. C.; Deacon, G. B.; Frank, R.; Fraser, B. H.; Junk, P. C.; MacLellan, J. G.; Massi, M.; Moubaraki, B.; Murray, K. S.; Silberstein, M. Formation of HoIII trinuclear clusters and GdIII monodimensional polymers induced by ortho and para regioisomers of pyridyl-functionalised β-diketones: synthesis, structure, and magnetic properties. Eur. J. Inorg. Chem. 2009, 2009, 744−751. (42) Xue, S.; Zhao, L.; Guo, Y. N.; Zhang, P.; Tang, J. K. The use of a versatile o-vanilloyl hydrazone ligand to prepare SMM-like Dy3 molecular cluster pair. Chem. Commun. 2012, 48, 8946−8948. (43) Abbas, G.; Lan, Y.; Kostakis, G. E.; Wernsdorfer, W.; Anson, C. E.; Powell, A. K. Series of isostructural planar lanthanide complexes [Ln4III(μ3-OH)2(mdeaH)2(piv)8] with single molecule magnet behavior for the Dy4 analogue. Inorg. Chem. 2010, 49, 8067−8072. (44) Lin, S. Y.; Zhao, L.; Ke, H.; Guo, Y. N.; Tang, J. K.; Guo, Y.; Dou, J. Steric hindrances create a discrete linear Dy4 complex exhibiting SMM behavior. Dalton Trans 2012, 41, 3248−3252. (45) Chandrasekhar, V.; Das, S.; Dey, A.; Hossain, S.; Sutter, J. P. Tetranuclear lanthanide (III) complexes containing dimeric subunits: single-molecule magnet behavior for the Dy4 analogue. Inorg. Chem. 2013, 52, 11956−11965. (46) Chandrasekhar, V.; Hossain, S.; Das, S.; Biswas, S.; Sutter, J. P. Rhombus-shaped tetranuclear [Ln4] complexes [Ln = Dy(III) and Ho(III)]: synthesis, structure, and SMM behavior. Inorg. Chem. 2013, 52, 6346−6353. (47) Wang, W. M.; Kang, X. M.; Shen, H. Y.; Wu, Z. L.; Gao, H. L.; Cui, J. Z. Modulating single-molecule magnet behavior towards multiple magnetic relaxation processes through structural variation in Dy4 clusters. Inorg. Chem. Front. 2018, 5, 1876−1885. (48) Sharples, J. W.; Zheng, Y. Z.; Tuna, F.; McInnes, E. J. L.; Collison, D. Lanthanide discs chill well and relax slowly. Chem. Commun. 2011, 47, 7650−7652. (49) Blagg, R. J.; Muryn, C. A.; McInnes, E. J. L.; Tuna, F.; Winpenny, R. E. P. Single pyramid magnets: Dy5 pyramids with slow magnetic relaxation to 40 K. Angew. Chem., Int. Ed. 2011, 50, 6530−6533. (50) Lin, S. Y.; Wernsdorfer, W.; Ungur, L.; Powell, A. K.; Guo, Y. N.; Tang, J.; Zhao, L.; Chibotaru, L. F.; Zhang, H. J. Coupling Dy3 triangles to maximize the toroidal moment. Angew. Chem., Int. Ed. 2012, 51, 12767−12771. (51) Das, S.; Hossain, S.; Dey, A.; Biswas, S.; Sutter, J. P.; Chandrasekhar, V. Molecular magnets based on homometallic hexanuclear lanthanide(III) complexes. Inorg. Chem. 2014, 53, 5020− 5028. (52) Wang, G. J.; Wei, Y. Q.; Wu, K. C. Goblet-shaped pentanuclear lanthanide clusters assembled with a cyclen derivative ligand exhibiting slow magnetic relaxation. Dalton Trans 2016, 45, 12734−12738. (53) Zhang, H. F.; Liu, R.; Zhang, J.; Li, Y. H.; Liu, W.; Dong, Y. P. Five rare μ4-O-centered Ln6 clusters with single-molecule magnet behavior for Dy6. Chem. - Asian J. 2017, 12, 507−514. (54) Li, X. L.; Wu, J. F.; Tang, J. K.; Le Guennic, B.; Shi, W.; Cheng, P. A planar triangular Dy3+Dy3 single-molecule magnet with a toroidal magnetic moment. Chem. Commun. 2016, 52, 9570−9573. (55) Li, X. L.; Wu, J. F.; Zhao, L.; Shi, W.; Cheng, P.; Tang, J. K. Endto-end azido-pinned interlocking lanthanide squares. Chem. Commun. 2017, 53, 3026−3029. (56) Bala, S.; Bishwas, M. S.; Pramanik, B.; Khanra, S.; Fromm, K. M.; Poddar, P.; Mondal, R. Construction of Polynuclear Lanthanide (Ln = DyIII, TbIII, and NdIII) Cage Complexes Using Pyridine−PyrazoleD
DOI: 10.1021/acs.inorgchem.8b01923 Inorg. Chem. XXXX, XXX, XXX−XXX
Communication
Inorganic Chemistry Based Ligands: Versatile Molecular Topologies and SMM Behavior. Inorg. Chem. 2015, 54, 8197−8206. (57) Ganivet, C. R.; Ballesteros, B.; de la Torre, G.; Clemente-Juan, J. M.; Coronado, E.; Torres, T. Influence of peripheral substitution on the magnetic behavior of single-ion magnets based on homo- and heteroleptic TbIII bis(phthalocyaninate). Chem. - Eur. J. 2013, 19, 1457−1465. (58) Gatteschi, D.; Sessoli, R. Quantum tunneling of magnetization and related phenomena in molecular materials. Angew. Chem., Int. Ed. 2003, 42, 268−297. (59) Wang, X. L.; Li, L. C.; Liao, D. Z. Slow magnetic relaxation in lanthanide complexes with chelating nitronyl nitroxide radical. Inorg. Chem. 2010, 49, 4735−4737. (60) Han, T.; Shi, W.; Zhang, X. P.; Li, L. L.; Cheng, P. A family of binuclear dysprosium(III) radical compounds with magnetic relaxation in ON and OFF states. Inorg. Chem. 2012, 51, 13009−13016. (61) Woodruff, D. N.; Winpenny, R. E. P.; Layfield, R. A. Lanthanide single-molecule magnets. Chem. Rev. 2013, 113, 5110−5148. (62) Hu, P.; Wang, X. F.; Ma, Y.; Wang, Q. L.; Li, L. C.; Liao, D. Z. A new family of Ln-radical chains (Ln = Nd, Sm, Gd, Tb and Dy). Synthesis, structure, and magnetic properties. Dalton Trans 2014, 43, 2234−2243. (63) Demir, S.; Jeon, I. R.; Long, J. R.; Harris, T. D. Radical ligandcontaining single-molecule magnets. Coord. Chem. Rev. 2015, 289-290, 149−176. (64) Rinehart, J. D.; Fang, M.; Evans, W. J.; Long, J. R. A N23- radicalbridged terbium complex exhibiting magnetic hysteresis at 14 K. J. Am. Chem. Soc. 2011, 133, 14236−14239. (65) Rinehart, J. D.; Fang, M.; Evans, W. J.; Long, J. R. Strong exchange and magnetic blocking in N-2(3-)-radical-bridged lanthanide complexes. Nat. Chem. 2011, 3, 538−542. (66) Demir, S.; Zadrozny, J. M.; Nippe, M.; Long, J. R. Exchange coupling and magnetic blocking in bipyrimidyl radical-bridged dilanthanide complexes. J. Am. Chem. Soc. 2012, 134, 18546−18549. (67) Demir, S.; Gonzalez, M. I.; Darago, L. E.; Evans, W. J.; Long, J. R. Giant coercivity and high magnetic blocking temperatures for N-2(3-) radical-bridged dilanthanide complexes upon ligand dissociation. Nat. Commun. 2017, 8, 2144−2152. (68) Liu, R. N.; Ma, Y.; Yang, P. P.; Song, X. Y.; Xu, G. F.; Tang, J. K.; Li, L. C.; Liao, D. Z.; Yan, S. P. Dynamic magnetic behavior and magnetic ordering in one-dimensional Tb-nitronyl nitroxide radical chain. Dalton Trans 2010, 39, 3321−3325. (69) Han, T.; Shi, W.; Niu, Z.; Na, B.; Cheng, P. Magnetic blocking from exchange interactions: slow relaxation of the magnetization and hysteresis loop observed in a dysprosium-nitronyl nitroxide chain compound with an antiferromagnetic ground state. Chem. - Eur. J. 2013, 19, 994−1001. (70) Li, L. L.; Liu, S.; Zhang, Y.; Xu, N.; Cheng, P. Two new mononuclear tri-spin lanthanide-nitronyl nitroxide radical complexes: syntheses, structure and magnetic properties. Inorg. Chem. Commun. 2015, 57, 51−53. (71) Ogita, M.; Yamamoto, Y.; Suzuki, T.; Kaizaki, S. Syntheses, structures, and spectroscopic properties of cobalt(III) complexes containing 3- or 4-pyridyl-substituted nitronyl and imino nitroxide ligands. Eur. J. Inorg. Chem. 2002, 2002, 886−894. (72) Volodarsky, L. B.; Reznikov, V. A.; Ovcharenko, V. I. Synthetic Chemistry of Stable Nitroxides; CRC Press: Boca Raton, FL, 1994. (73) Furui, T.; Suzuki, S.; Kozaki, M.; Shiomi, D.; Sato, K.; Takui, T.; Okada, K.; Tretyakov, E. V.; Tolstikov, S. E.; Romanenko, G. V.; Ovcharenko, V. I. Preparation and Magnetic Properties of MetalComplexes from N-t-Butyl-N-oxidanyl-2-amino-(nitronyl nitroxide). Inorg. Chem. 2014, 53, 802−809. (74) Zhou, S. Y.; Li, T.; Li, X.; Sun, Y. Q.; Wang, Q. L.; Liao, D. Z.; Tian, L. Syntheses, structures, and magnetic characterizations of five Mn(II) and Co(II) complexes based on 2,6-Pyridyl-substituted nitronyl and imino nitroxide radical. Inorg. Chim. Acta 2016, 444, 131−140.
(75) Guo, F. S.; Layfield, R. A. Strong direct exchange coupling and single-molecule magnetism in indigo-bridged lanthanide dimmers. Chem. Commun. 2017, 53, 3130−3133.
E
DOI: 10.1021/acs.inorgchem.8b01923 Inorg. Chem. XXXX, XXX, XXX−XXX
