Magnetization Dynamics Changes of Dysprosium(III) Single-Ion

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Magnetization Dynamics Changes of Dysprosium(III) Single-Ion Magnets Associated with Guest Molecules Sheng Zhang,†,§ Hongshan Ke,† Lin Sun,† Xin Li,† Quan Shi,‡ Gang Xie,† Qing Wei,† Desuo Yang,§ Wenyuan Wang,† and Sanping Chen*,† †

Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi’an, Shaanxi 710069, China ‡ Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China § College of Chemistry and Chemical Engineering, Baoji University of Arts and Sciences, Baoji 721013, China S Supporting Information *

ABSTRACT: Two Dy(III) single-ion magnets with a trigonal dodecahedron (D2d) for 1 and an approximately squareantiprismatic (SAP, D4d) N2O6 coordination environment for 2, formulated as [Dy(Phen)(tfmb)3] (1) and [Dy(Phen)(tfmb)3]·0.5(1,4-dioxane) (2) (tfmb = 4,4,4-trifluoro-1-(4methylphenyl)-1,3-butanedione, Phen = 1,10-phenanthroline), were obtained. Therein, complex 1 was transformed to 2 in 1,4dioxane solution. Structural analysis shows that complexes 1 and 2 have differing local symmetry of Dy(III) ions. Magnetic studies indicate that the barrier heights (ΔE/kB) of 1 and 2 are 63.56 and 102.82 K under zero dc field as well as 118.50 and 164.55 K under 1200 Oe dc field, respectively. Based on the frequency dependencies of the ac susceptibilities, the effective barriers (ΔE/kB) and the pre-exponential factors (τ0) are 67.05 K and 4.57 × 10−6 s for 1 and 95.88 K and 2.39 × 10−7 s for 2 under zero dc field. The present work illustrates that guest-determined notable structure change results in different barrier heights.

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INTRODUCTION Since the first observation with slow magnetic relaxation of the sandwich complex [N(C4H9)4]+[LnPc2]− (Ln = Tb, Dy) in 2003,1 mononuclear single-molecule magnets (SMMs), commonly called single-ion magnets (SIMs), have received considerable attention because the relatively simple mononuclear system with an excellent model is convenient for understanding magneto-structural correlation, such as singleion anisotropy, dipolar spin−spin interactions, and so on.2,3 As the ideal candidates, lanthanide ions with intrinsic strong spin− orbit coupling and large magnetic anisotropy2d,4,5 have been gradually recognized and employed for preparing SIMs with phthalocyanine,1,6 polyoxometalate,7 β-diketone,8 macrocyclic Schiff base ligand,9 or other unusual aromatic ligands.10 As reported,3 the ligand field of an axial symmetry, of which the point groups are symbolized as D4d, D2d, D5h, D∞h, S8 (I4), D6d, D5h, C3v, and so on, is given different priorities to lanthanide SIM construction. In the case of a similar configuration with the same symmetry, the magnetization dynamics of SIMs could be regulated with the changes of ligand field (LF). Coincidentally, a series of β-diketonate-based square-antiprismatic (SAP, D4d) SIMs were reported by the S. Gao and J. Tang groups, respectively. The results indicate that the different capping ligands effectively affect the anisotropy barriers.8e−h No doubt, © XXXX American Chemical Society

for lanthanide ions, the single-ion magnetic anisotropy is particularly sensitive to subtle changes of the ligand field or the local geometrical symmetry.2 Additionally, in the referenced SMMs or SMM-MOFs,11,12 the effective energy barrier could also be affected through introducing fast quantum tunneling of the magnetization resulted from hyperfine couplings, dipolar spin−spin interactions, or transverse internal fields. Recently, Gao et al. reported a lanthanide MOF featuring binuclear Dy2 SMMs, in which the exchange of guest molecules within the pores has an great influence on the magnetization relaxation dynamics.12 In detail, the slight structural changes based on the exchange of guest molecules result in different dipole−dipole interactions, finally impacting on the relaxation rate of incoherent quantum tunneling to obtain hugely different effective relaxation barriers. To sum up, to find a feasible strategy to regulate and control the single-ion magnetic anisotropy or dipolar spin−spin interactions in SIMs would always be a active direction for understanding magneto-structural correlation in depth and developing magnetic materials with high anisotropic energy barrier (Ueff) and blocking temperature (TB). Herein, a kind of Received: December 28, 2015

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DOI: 10.1021/acs.inorgchem.5b02971 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry β-diketonate ligand, 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (tfmb) and the lanthanide ion, Dy(III) ion, become our first choice based on the following reasons: (1) The classical β-diketonate ligands usually coordinate with metal ions in bidentate chelating modes in SMMs, which the suitable ligand field is beneficial for discussing the magnetic anisotropy.8 (2) The Dy(III) ion has a large angular moment with a Kramers ground state of 6H15/2 and is assumed to have a large Ising-type magnetic anisotropy.13 In addition, with the introduction of a capping ligand, the metal ions would be apt to exhibit Ising-type ground states with a local symmetry of D4d or D2d, which is a yearning configuration to behave as a SIM and is sensitive to the subtle changes of the ligand field.4,8,14 Fortunately, a mononuclear complex, [Dy(Phen)(tfmb)3] (1) (Phen = 1,10-phenanthroline), was obtained through solution reaction. Furthermore, complex 1 was transformed to [Dy(Phen)(tfmb)3]·0.5(1,4-dioxane) (2) in 1,4-dioxane. Complex 1 has a trigonal dodecahedron (D2d) configuration of Dy(III) ions, while complex 2 shows an approximately squareantiprismatic (SAP) N2O6 coordination environment of Dy(III) ions. The uncoordinated 1,4-dioxane molecules exist in 2. Unexpectedly, magnetic susceptibility measurements indicate that the slight structural changes induced by guest solvents produce drastically different effective relaxation barriers.

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diffractometer equipped with graphite-monochromatized Mo Kα radiation (λ = 0.710 73 Å) using ω and φ scan mode. The data integration and reduction were processed with SAINT software. Absorption correction based on multiscan was performed using the SADABS program.15 The structures were solved by the direct method using SHELXTL and refined by means of full-matrix least-squares procedures on F2 with the SHELXL-97 program.16 All non-hydrogen atoms were refined anisotropically. Other details of crystal data, data collection parameters, and refinement statistics are given in Table 1. The selected bond lengths and angles are listed in Table S1.

Table 1. Crystal Data and Structure Refinement Details for Complexes 1 and 2 empirical formula formula weight temperature (K) crystal system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V (Å3) Z F(000) goodness of fit on F̂2 final R indices [I > 2σ(I)]

EXPERIMENTAL SECTION

Materials and Instrumentation. Commercially available reagents were used as received. Fourier transform infrared (FT-IR) spectra were recorded in the range 400−4000 cm−1 using KBr pellets on an EQUINOX55 FT/IR spectrophotometer. Elemental analysis (C, H, N) was implemented on a Perkin-Elmer 2400 CHN elemental analyzer. The phase purity of the bulk or polycrystalline samples was confirmed by powder X-ray diffraction (PXRD) measurements executed on a Rigaku RU200 diffractometer at 60 kV, 300 mA, and Cu Kα radiation (λ = 1.5406 Å), with a scan speed of 5° min−1 and a step size of 0.02° in 2θ. Magnetic measurements were performed in the temperature range 1.9−300 K, using a Quantum Design MPMSXL-7 SQUID magnetometer on polycrystalline samples. The diamagnetic corrections for the complexes were estimated using Pascal’s constants. The details about the magnetic measurements have been recorded in the Supporting Information. Synthesis of Complex [Dy(Phen)(tfmb)3] (1). Dy(NO3)3·6H2O (0.25 mmol), Phen (0.1 mmol), and Et3N (0.10 mmol) were added to a methanol solution (10 mL). Furthermore, a methanol solution (10 mL) of 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione (0.3 mmol) was added with stirring about 30 min. The above solution was filtered and left unperturbed at room temperature. Finally, colorless block crystals were obtained after several days. Yield: 65% (based on the Dy(III) salt). Anal. Calcd for C45H32DyF9N2O6: C, 52.42; H, 3.11; N, 2.72. Found: C, 53.77; H, 3.32; N, 2.53. IR (KBr): 3077 (w), 1645 (s), 1623 (m), 1553 (s), 1564 (m), 1453 (w), 1401 (m), 1334 (w), 1299 (s), 1168 (m), 1111 (s), 1043 (w), 1009 (m), 923 (m), 833 (m), 801 (w), 775 (w), 722 (w), 677 (w), 611(m), 575 (w), 487 (m), 439 cm−1 (w). Synthesis of [Dy(Phen)(tfmb)3]·0.5C4H8O2 (2). The crystals of complex [Dy(Phen)(tfmb)3] (1) were immersed in an 1,4-dioxane solution (15 mL) at room temperature, and these crystals suffered a dissolution−precipitation process. Finally, pink block crystals were obtained after several days. Anal. Calcd for C47H36DyF9N2O7: C, 52.50; H, 3.35; N, 2.61. Found: C, 52.38; H, 3.52; N, 2.82. IR (KBr): 3092 (w), 1621 (s), 1589 (s), 1567 (s), 1533 (s), 1462 (m), 1401 (m), 1343 (w), 1302 (m), 1166 (m), 1145 (m), 1054 (w), 1022 (m), 921 (w), 846 (m), 766 (m), 755 (w), 732 (w), 681 (m), 587 (m), 572 (m), 481 (w), 443 (w), 409 (m) cm−1. X-ray Single-Crystal Diffraction Analysis. The single crystal Xray experiment was performed on a Rigaku SCX mini CCD

R indices (all data) CCDC

1

2

C45H32DyF9N2O6 1030.23 296(2) triclinic P1̅ 10.5725(17) 12.565(2) 18.395(3) 85.084(3) 75.023(3) 65.326(3) 2144.4(6) 2 1022 1.284 R1 = 0.0992 wR2 = 0.2218 R1 = 0.1261 wR2 = 0.2521 1430880

C47H36DyF9N2O7 1074.28 296(2) triclinic P1̅ 10.6972(16) 11.3656(16) 18.687(3) 81.692(2) 86.181(2) 84.660(3) 2235.1(6) 2 1070 1.068 R1 = 0.0558 wR2 = 0.1394 R1 = 0.0782 wR2 = 0.1654 1430879

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RESULTS AND DISCUSSION Description of the Structures. Complexes 1 and 2 are crystallized in the triclinic space group P1.̅ 1 and 2 have N2O6 coordination environment. Each Dy(III) ion is surrounded by three negative tfmb ions and a neutral capping ligand (Phen), as shown in Figure 1. Differently, half a free 1,4-dioxane molecule crystallizes in 2. Additionally, for 1 and 2, there is an appreciable variation in the b axis, which would be the origin of the different types of packing. The Dy−O distances are from 2.269 to 2.526 Å in 1 and from 2.307 to 2.340 Å in 2. Additionally, the Dy−N distances are 2.526 and 2.550 Å in 1 as well as 2.547 and 2.558 Å in 2. Through using the SHAPE 2.1 software, the configurations of DyIII ions in 1 and 2 were calculated (Table S2), indicating that complexes 1 and 2 belong to a trigonal dodecahedron (D2d) and an approximately squareantiprismatic (SAP, D4d) configuration, respectively.17 The α angles vary from 48.655 to 62.288° for 2 (Table S3). For 1, the neutral molecules are assisted by weak π−π stacking between the parallel interlayer (Figure S1), and the centroid distance is 3.767 Å, belonging to a slipped stacking and leading to the Dy···Dy distance of 9.193 Å. In 2, the neutral molecules are connected by weak C(171)−H(117)···O(7) interactions, leading to the Dy···Dy distance of 18.853 Å (Table S4 and Figure S2). The crystal packing also exists in many similar works. In [Dy(acac)3(dppn)]·C2H5OH (acac = acetylacetone, dppn = benzo[i]dipyrido-[3,2-a:2′,3′-c]phenazine),8j the crystal packing shows a one-dimensional (1D) supramolecular tape B


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Inorganic Chemistry

Figure 1. Coordination environments of Dy(III) ion in 1 (right) and 2 (left).

Figure 2. Temperature dependence of the χMT product at 1000 Oe for complexes 1 (left) and 2 (right). Inset: M vs H/T plots at 2.0, 3.0, and 5.0 K for complexes 1 (left) and 2 (right).

Figure 3. Temperature dependence of in-phase (χ′) and out-of-phase (χ″) ac susceptibilities for 1 under zero dc field.

Magnetic Properties. Under an applied magnetic field of 1000 Oe, direct-current (dc) magnetic susceptibility data of 1 and 2 were measured in the 2−300 K temperature range (Figure 2). The values of χMT of 1 and 2 are 14.16 and 14.24 cm3 mol−1 K at room temperature, respectively. The values are close to the expected value of a paramagnetic Dy(III) ion (6H15/2, S = 5/2, L = 5, J = 15/2, g = 4/3).13 As the temperature is lowered, the χMT values for complexes 1 and 2 start to decrease tardily from 300 to 100 K. Furthermore, the curves degrade rapidly and achieve minimum values of 9.63 cm3 mol−1 K for 1 and 9.24 cm3 mol−1 K for 2 at 2 K. These thermal behaviors could arise from the thermal depopulation of the Dy(III) Stark sublevels or weak antiferromagnetic interactions between molecules.4,13,17−19 The field dependence of the magnetization of 1 and 2 was measured at 2, 3, and 5 K, as shown in the insets of Figure 2. At 2 K, the magnetization measurements of 1 and 2 increase with a relatively rapid speed for weak fields. Furthermore, the curves of 1 and 2 increase with linear form up to the values of 6.24 and

connected through π−π stacking with centroid-to-centroid distances of 3.383 and 3.603 Å, resulting from the stacking dppn ligands with a parallel fashion. As shown in Table S5, the shortest Dy···Dy distance in 1 is slightly longer than those in [Dy(acac)3(dppn)]·C2H5OH (7.407 Å), [Dy(dppz)(acac)3]· CH3OH (7.34 Å), [Dy(Phen)(acac)3] (8.83 Å), and [Dy(dpq)(acac)3] (8.243 Å). For [Dy(TFI)3(Phen)]·0.02CHCl3 (TFI = 2-(2,2,2-trifluoroethyl)-1-indone, Phen = 1,10-phenanthroline),8k the adjacent molecules are connected through weak C−H···F interactions and π−π stacking between TFI and Phen with centroid-to-centroid distances of 3.756 and 3.612 Å. Meanwhile, the different types of weak interactions lead to Dy···Dy distances of 10.431 and 10.651 Å, respectively. For [Dy(acac)3(H2O)2],8g the neutral molecules are linked by hydrogen bonds. The Dy···Dy distances are 5.956 and 6.136 Å. The different types of weak interactions between the neutral molecules would result in different dipole−dipole interactions, finally influencing the magnetic behaviors. C


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Inorganic Chemistry

Figure 4. Temperature dependence of in-phase (χ′) and out-of-phase (χ″) ac susceptibilities for 2 under zero dc field.

Figure 5. Frequency dependence of in-phase (χ′) and out-of-phase (χ″) ac susceptibilities for 1 under zero dc field.

Figure 6. Frequency dependence of in-phase (χ′) and out-of-phase (χ″) ac susceptibilities for 2 under zero dc field.

magnetization. On cooling, χ′ and χ″ increase again below 8 K. The appearances of the characteristic in 1 and 2 reveal the onset of pure quantum tunneling, which is commonly observed in other lanthanide SMMs or SIMs.6−10 The relaxation time τ data of complexes 1 and 2 derived from the χ″ peaks follow the Arrhenius law [τ = τ0 exp(ΔE/kBT)] (τ = relaxation time; τ0 = pre-exponential factor; ΔE = energy gap). The pre-exponential factor (τ0) and the effective barrier (ΔE/kB) are 4.48 × 10−6 s and 63.56 K for 1 and 1.19 × 10−7 s and ΔE/kB = 102.82 K for 2 (Figure S6), respectively. The obtained anisotropic energy barriers and the relaxation times are similar to those reported for Dy-based complexes.3,6−10,13 To probe the feasibility of lowering the relaxation probability via the quantum pathway, under an applied dc field of 1200 Oe, the ac susceptibilities were further measured (Figures S7 and S8). At this dc field, ac susceptibility measurements were performed in the range 2−25 K and at frequencies of 1, 33, 300, 500, 800, and 999 Hz for 1. Those for 2 were measured in the range 2−20 K and at frequencies of 1, 10, 33, 100, 300, 499, 801, 997, 1302, and 1488 Hz. The results indicate that both in-phase (χ′) and outof-phase (χ″) susceptibilities come down in the low-temper-

5.74 Nβ at 70 kOe, respectively. The expected saturation value of 10 Nβ is not achieved.20 Additionally, based on the M vs H/ T data, all the curves show nonsuperposition on a single master curve. The phenomenon corresponds to significant magnetic anisotropy and/or low-lying excited states.13a,19,20 The observations of butterfly shaped hysteresis loops at 2 K for 1 and 2 through the M vs H data (Supporting Information, Figures S4 and S5) suggest fast zero-field relaxation between the two ground states. At 5 K, 1 affords a weak butterfly shaped hysteresis loop. However, the hysteresis effects are not observed for 1 and 2 above 5 K. For 1, under an oscillating field of 3.5 Oe, the zero-field alternating-current (ac) susceptibility experiments were determined in the range 2−25 K. The frequencies selected were 1, 33, 100, 300, 500, 800, and 1000 Hz in 1. However, for 2, zerofield ac susceptibilities were measured in the range 2−18 K. The frequencies employed were 100, 300, 499, 801, 997, 1302, and 1488 Hz in 2. At a relatively high temperature range, the inphase (χ′) and out-of-phase (χ″) susceptibilities in 1 and 2 show significant temperature dependence peaks (Figures 3 and 4). The characteristic clearly indicates the slow relaxation of D


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Inorganic Chemistry

Figure 7. Cole−Cole plots for 1 (left, 3−30 K) and 2 (right, 2−25 K) using the ac susceptibility data shown in Figures 5 and 6. The solid lines are to guide the eye.

doubly degenerate sublevels (formally corresponding to large Jz values of ±11/2 or ±13/2 for dysprosium8h) is inclined to be affected through the degree of longitudinal compression or elongation under the same ground-state condition. Compared with the ideal SAP configuration and reported references with the local symmetry of D4d, different deviations can be observed, especially for α angles, and may finally result in different values of the effective barriers (Table S5). Magnetic analyses indicate that 2 possesses a higher energy barrier than 1. The difference above may be attributed to the different local symmetry and the bond distances resulting in different ligand fields in 1 (D2d) and 2 (D4d). A similar phenomenon was observed by Gao et al.8c In their work, they reported two mononuclear Dy(III) complexes, showing different local symmetries of Dy(III) ions (D2d and D4d, respectively). The energy barrier of complex-D4d (130.42 K) is much higher than that of complex-D2d (35.09 K). Obviously, the local symmetry of Dy(III) ions has a great effect on magnetic behaviors. Furthermore, the calculation analysis indicates that the ground states are |MJ = ±15/2⟩ with |MJ = ±1/2⟩ as the first excited state for complex-D2d and |MJ = ±15/ 2⟩ with |MJ = ±3/2⟩ as the first excited state for complex-D4d. The results reveal typical Ising-type splitting in 1 and 2. Meanwhile, the explanation above is responsible for the different slow relaxation behaviors of 1 and 2. The disparity of quantum tunneling rates can be noticed in 1 and 2. Probably this slight but absolutely important difference for the respective structures influences the nature of high order transverse anisotropy. In other words, the magnitude of Ueff does not only depend on the local symmetry of the Dy(III) ion but also, and most importantly, depends on the existence of an axial crystal field around the Dy(III) ion, which can be obtained by increasing the electron density of the donor atoms near the axial axis. Additionally, for 1, the neutral molecules are connected by hydrogen bonds with a Dy···Dy distance of 9.193 Å (Figure S1). For 2, the neutral molecules are assisted by weak π−π stacking with a Dy···Dy distance of 18.853 Å (Figure S2). The dipole−dipole interaction could influence the magnetic behavior (the quantum tunneling), which has been corroborated by many cases.8f,g Herein, the different types of weak interactions between the neutral molecules lead to different dipole−dipole interactions, which also have an influence on the magnetization dynamics of 1 and 2.12 It is the rare example that guest molecules change the magnetization dynamics and then energy barriers for SIMs.

ature range. The relaxation probability via the quantum pathway has been obviously weakened or even disappears below 8 K. The magnetization relaxation times τ derived from the temperature-dependence measurements are plotted as a function of 1/T in Figure 4. Through modeling the behavior with Arrhenius plots for high temperature data, the preexponential factor (τ0) and the effective barrier (ΔE/kB) were obtained as 1.5 × 10−7 s and 118.50 K for 1 and 2.0 × 10−9 s and 164.55 K for 2 (Figure S9). Additionally, the dynamics of the magnetization of 1 and 2 were further studied. The frequency dependencies of the alternating-current (ac) susceptibility were measured under zero dc field (Figures 5 and 6). The in-phase (χ′) and out-ofphase (χ″) signals of 1 and 2 show frequency dependencies. Meanwhile, the slow relaxation of the magnetization in 1 and 2 was observed. Obviously, with increasing temperature, the peaks of the out-of-phase ac susceptibility (χ″) in 1 gradually shift from low frequency to high frequency. The peaks of 2 gradually shift from middle frequency to high frequency. The magnetization relaxation time (τ) has been estimated (Figure S10) depending on the frequency dependencies of the ac susceptibility. Finally, based on the Arrhenius law, the preexponential factor (τ0) and the effective barrier (ΔE/kB) are 4.57 × 10−6 s and 67.05 K for 1 and 2.39 × 10−7 s and 95.88 K for 2. The values are consistent with the front values extracted from the temperature-dependent data. It is worth noting that ln τ values of 1 and 2 become weakly dependent on 1/T with decreasing temperature. The characteristic reveals a crossover from a thermally activated Orbach mechanism that is predominant at high temperature to a Raman process.12,18 Cole−Cole plots of χ″ vs χ′ (Figure 7) from 3 to 19 K for 1 show an evolution from asymmetrical arcs to semicircular profiles. These curves were fitted to a generalized Debye model. For 2, Cole−Cole plots show ideal semicircular profiles from 2 to 16 K. α parameters below 0.21 (Figure S11 and Table S6) for 1 and below 0.31 for 2 (Figure S12 and Table S7) indicate a narrow distribution of relaxation time.21,22 The dynamics of the magnetization reveal significant differences in 1 and 2, indicating the influence of the guest molecules on differing relaxation mechanisms. Comparison and Discussion of Sources of the Magnetic Variations. From a structural view, Dy(III) ions in 1 and 2 show a trigonal dodecahedron (D2d) and an approximately square-antiprismatic (SAP) N2O6 coordination environment, respectively. The Dy−O distances and the Dy−N distances show different values for 1 and 2. As is known, for the SAP environment, the energy difference between the lowest E


Inorganic Chemistry

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CONCLUSION A mononuclear complex, [Dy(Phen)(tfmb)3] (1) (tfmb = 4,4,4-trifluoro-1-(4-methylphenyl)-1,3-butanedione, Phen = 1,10-phenanthroline), was synthesized. In 1,4-dioxane solution, 1 was transformed to [Dy(Phen)(tfmb)3]·0.5(1,4-dioxane) (2). The coordination geometry of Dy(III) ions in 1 can be best described as a trigonal dodecahedron (D2d). The Dy(III) ions in 2 show an approximately square-antiprismatic (SAP, D4d) N2O6 coordination environment. Guest 1,4-dioxane molecules are observed in 2. The different types of weak interactions exist in 1 (π−π stacking) and 2 (hydrogen bonds), respectively, leading to the different distances of Dy···Dy and further influence the dipolar spin−spin interactions. The temperaturedependent out-of-phase ac susceptibility peaks are observed in the absence of a static dc field, resulting in the pre-exponential factor τ0 = 4.48 × 10−6 s and the effective barrier ΔE/kB = 63.56 K for 1 and τ0 = 1.19 × 10−7 s and ΔE/kB = 102.82 K for 2 based on Arrhenius fitting. It is interesting that the quantum tunneling of the magnetization was suppressed when one optimum dc field (1200 Oe) was applied with the preexponential factor τ0 = 1.5 × 10−7 s and the effective barrier ΔE/kB = 118.50 K for 1 and τ0 = 2.0 × 10−9 s and ΔE/kB = 164.55 K for 2. Under zero dc field, the measurements of the frequency dependencies of the alternating-current (ac) susceptibility show the pre-exponential factor τ0 = 4.57 × 10−6 s and the effective barrier ΔE/kB = 67.05 K for 1 and τ0 = 2.39 × 10−7 s and ΔE/kB = 95.88 K for 2, respectively. Magnetic susceptibility measurements reveal that the subtle structural changes associated with guest solvent yield a drastically different effective relaxation barrier. This work offers a new example to change the magnetization dynamics and further understand magneto-structural correlation for Dy(III) SIMs.

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REFERENCES

(1) Ishikawa, N.; Sugita, M.; Ishikawa, T.; Koshihara, S.; Kaizu, Y. J. Am. Chem. Soc. 2003, 125, 8694−8695. (2) (a) Fortea-Pérez, F. R.; Vallejo, J.; Julve, M.; Lloret, F.; De Munno, G.; Armentano, D.; Pardo, E. Inorg. Chem. 2013, 52, 4777− 4779. (b) Vallejo, J.; Pascual-Á lvarez, A.; Cano, J.; Castro, I.; Julve, M.; Lloret, F.; Krzystek, J.; De Munno, G.; Armentano, D.; Wernsdorfer, W.; Ruiz-García, R.; Pardo, E. Angew. Chem., Int. Ed. 2013, 52 (52), 14075−14079. (c) Jeon, I. R.; Clérac, R. Dalton Trans. 2012, 41, 9569−9586. (d) Sun, W. B.; Yan, P. F.; Jiang, S. D.; Wang, B. W.; Zhang, Y. Q.; Li, H. F.; Chen, P.; Wang, Z. M.; Gao, S. Chem. Sci. 2016, 7, 684−691. (3) Huang, X. C.; Zhang, M.; Wu, D. Y.; Shao, D.; Zhao, X. H.; Huang, W.; Wang, X. Y. Dalton Trans. 2015, 44, 20834−20838. (4) (a) Rinehart, J. D.; Long, J. R. Chem. Sci. 2011, 2, 2078−2085. (b) Wang, W. M.; Wang, S. Y.; Zhang, H. X.; Shen, H. Y.; Zou, J. Y.; Gao, H. L.; Cui, J. Z.; Zhao, B. Inorg. Chem. Front. 2016, 3, 133−141. (5) Skomski, R. Simple Models of Magnetism; Oxford University Press: Oxford, 2008. (6) Ishikawa, N.; Sugita, M.; Ishikawa, T.; Koshihara, S. Y.; Kaizu, Y. J. Phys. Chem. B 2004, 108, 11265−11271. (7) (a) AlDamen, M. A.; Clemente-Juan, J. M.; Coronado, E.; MartíGastaldo, C.; Gaita-Ariño, A. J. Am. Chem. Soc. 2008, 130, 8874−8875. (b) AlDamen, M. A.; Cardona-Serra, S.; Clemente-Juan, J. M.; Coronado, E.; Gaita-Ariño, A.; Martí-Gastaldo, C.; Luis, F.; Montero, O. Inorg. Chem. 2009, 48, 3467−3479. (8) (a) Li, D. P.; Wang, T. W.; Li, C. H.; Liu, D. S.; Li, Y. Z.; You, X. Z. Chem. Commun. 2010, 46, 2929−2931. (b) Dong, Y. P.; Yan, P. F.; Zou, X. Y.; Li, G. M. Inorg. Chem. Front. 2015, 2, 827−836. (c) Tong, Y. Z.; Gao, C.; Wang, Q. L.; Wang, B. W.; Gao, S.; Cheng, P.; Liao, D. Z. Dalton Trans. 2015, 44, 9020−9026. (d) Dong, Y. P.; Yan, P. F.; Zou, X. Y.; Liu, T. Q.; Li, G. M. J. Mater. Chem. C 2015, 3, 4407− 4415. (e) Chen, G. J.; Gao, C. Y.; Tian, J. L.; Tang, J. K.; Gu, W.; Liu, X.; Yan, S. P.; Liao, D. Z.; Cheng, P. Dalton Trans. 2011, 40, 5579− 5583. (f) Bi, Y.; Guo, Y. N.; Zhao, L.; Guo, Y.; Lin, S. Y.; Jiang, S. D.; Tang, J. K.; Wang, B. W.; Gao, S. Chem. - Eur. J. 2011, 17, 12476− 12481. (g) Jiang, S. D.; Wang, B. W.; Su, G.; Wang, Z. M.; Gao, S. Angew. Chem., Int. Ed. 2010, 49, 7448−7451. (h) Chen, G. J.; Guo, Y. N.; Tian, J. L.; Tang, J. K.; Gu, W.; Liu, X.; Yan, S. P.; Cheng, P.; Liao, D. Z. Chem. - Eur. J. 2012, 18, 2484−2487. (i) Wang, C.; Lin, S. Y.; Wu, J. F.; Yuan, S. W.; Tang, J. K. Dalton Trans. 2015, 44, 4648−4654. (j) Chen, G. J.; Zhou, Y.; Jin, G. X.; Dong, Y. B. Dalton Trans. 2014, 43, 16659−16665. (k) Zhu, J.; Wang, C. Z.; Luan, F.; Liu, T. Q.; Yan, P. F.; Li, G. M. Inorg. Chem. 2014, 53, 8895−8901. (9) (a) Yamashita, A.; Watanabe, A.; Akine, S.; Nabeshima, T.; Nakano, M.; Yamamura, T.; Kajiwara, T. Angew. Chem. 2011, 123, 4102−4105. (b) Feltham, H. L. C.; Lan, Y.; Klöwer, F.; Ungur, L.; Chibotaru, L. F.; Powell, A. K.; Brooker, S. Chem. - Eur. J. 2011, 17, 4362−4365. (10) Jiang, S. D.; Wang, B. W.; Sun, H. L.; Wang, Z. M.; Gao, S. J. Am. Chem. Soc. 2011, 133, 4730−4733. (11) (a) Gatteschi, D.; Sessoli, R. Angew. Chem., Int. Ed. 2003, 42, 268−297. (b) Ishikawa, N.; Sugita, M.; Wernsdorfer, W. J. Am. Chem. Soc. 2005, 127, 3650−3651. (c) Ishikawa, N.; Sugita, M.; Wernsdorfer, W. Angew. Chem., Int. Ed. 2005, 44, 2931−2935. (d) Gao, F.; Yang, F. L.; Zhu, G. Z.; Zhao, Y. Dalton Trans. 2015, 44, 20232−20241. (e) Vallejo, J.; Fortea-Pérez, F. R.; Pardo, E.; Benmansour, S.; Castro, I.; Krzystek, J.; Armentano, D.; Cano, J. Chem. Sci. 2016, 7, 2286− 2293. (12) 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. Angew. Chem., Int. Ed. 2015, 54, 9861−9865. (13) (a) Tang, J. K.; Hewitt, I.; Madhu, N. T.; Chastanet, G.; Wernsdorfer, W.; Anson, C. E.; Benelli, C.; Sessoli, R.; Powell, A. K. Angew. Chem., Int. Ed. 2006, 45, 1729−1733. (b) Guo, Y. N.; Xu, G. F.; Gamez, P.; Zhao, L.; Lin, S. Y.; Deng, R.; Tang, K. J.; Zhang, H. J. J. Am. Chem. Soc. 2010, 132, 8538−8539. (c) Zhang, S.; Ke, H. S.; Liu, X. Y.; Wei, Q.; Xie, G.; Chen, S. P. Chem. Commun. 2015, 51, 15188− 15191. (d) Wang, Y. X.; Shi, W.; Li, H.; Song, Y.; Fang, L.; Lan, Y. H.;

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.5b02971. Crystallographic data for the structures reported in this article have been deposited in the Cambridge Crystallographic Data Center with CCDC reference numbers 1430880 and 1430879 for complexes 1 and 2, respectively. Magnetization data and PXRD patterns (PDF) X-ray crystallographic file for C45H32DyF9N2O6 (CIF) X-ray crystallographic file C47H36DyF9N2O7 (CIF)

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AUTHOR INFORMATION

Corresponding Author

*Tel.: +86-029-81535026. Fax: +86-029-81535026. E-mail: [email protected]. Author Contributions

S.Z. and H.K. contributed equally to this work. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS We gratefully acknowledge financial support from the National Natural Science Foundation of China (Grants 21373162, 21463020, 21073142, and 21173168) and the Natural Science Foundation of Shanxi Province (Grants 11JS110, 2013JM2002, and SJ08B09). F


Article

Inorganic Chemistry Powell, A. K.; Wernsdorfer, W.; Ungur, L.; Chibotaru, L. F.; Shen, M. R.; Cheng, P. Chem. Sci. 2012, 3, 3366−3370. (e) Guo, Y. N.; Xu, G. F.; Wernsdorfer, W.; Ungur, L.; Guo, Y. N.; Tang, J. K.; Zhang, H. J.; Chibotaru, L. F.; Powell, A. K. J. Am. Chem. Soc. 2011, 133, 11948− 11951. (f) Zhang, P.; Zhang, L.; Wang, C.; Xue, S. F.; Lin, S. Y.; Tang, J. K. J. Am. Chem. Soc. 2014, 136, 4484−4487. (g) Guo, Y. N.; Ungur, L.; Granroth, G. E.; Powell, A. K.; Wu, C. J.; Nagler, S. E.; Tang, J. K.; Chibotaru, L. F.; Cui, D. M. Sci. Rep. 2014, 4, 5471−5477. (h) Zhang, P.; Guo, Y. N.; Tang, J. K. Coord. Chem. Rev. 2013, 257, 1728−1763. (i) Ungur, L.; Lin, S. Y.; Tang, J. K.; Chibotaru, L. F. Chem. Soc. Rev. 2014, 43, 6894−6905. (14) (a) Murugesu, M. Nat. Chem. 2012, 4, 347−348. (b) Baldovi, J. J.; Cardona-Serra, S.; Clemente-Juan, J. M.; Coronado, E.; Gaita-Arino, A.; Palii, A. Inorg. Chem. 2012, 51, 12565−12574. (c) Guo, Y. N.; Xu, G. F.; Guo, N. Y.; Tang, J. K. Dalton Trans. 2011, 40, 9953−9963. (15) Sheldrick, G. M. SADABS, Program for Empirical Absorption Correction; University of Göttingen, Göttingen, Germany, 1996. (16) Sheldrick, G. M. SHELXTL; Bruker Analytical X-ray Instruments, Inc.: Madison, WI, 1998. (17) Ke, H. S.; Zhang, S.; Li, X.; Wei, Q.; Xie, G.; Wang, W. Y.; Chen, S. P. Dalton Trans. 2015, 44, 21025−21031. (18) (a) Zhang, L.; Zhang, P.; Zhao, L.; Lin, S. Y.; Xue, S. F.; Tang, J. K.; Liu, Z. L. Eur. J. Inorg. Chem. 2013, 2013, 1351−1357. (b) Joarder, B.; Chaudhari, A. K.; Rogez, G.; Ghosh, S. K. Dalton Trans. 2012, 41, 7695−7699. (19) Liang, L.; Peng, G.; Li, G. Z.; Lan, Y. H.; Powell, A. K.; Deng, H. Dalton Trans. 2012, 41, 5816−5823. (20) Osa, S.; Kido, T.; Matsumoto, N.; Re, N.; Pochaba, A.; Mrozinski, J. J. Am. Chem. Soc. 2004, 126, 420−421. (21) Zhang, H. X.; Lin, S. Y.; Xue, S. F.; Wang, C.; Tang, J. K. Dalton Trans. 2014, 43, 6262−6268. (22) (a) Suzuki, K.; Sato, R.; Mizuno, N. Chem. Sci. 2013, 4, 596− 600. (b) Cole, K. S.; Cole, R. H. J. Chem. Phys. 1941, 9, 341−351.

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