Synthesis and Magnetic Characterization of Fe(III)-Based 9-Metallacrown-3. Complexes Which Exhibit Magnetorefrigerant Properties

Transcription

1 SUPPORTING INFORMATION Synthesis and Magnetic Characterization of Fe(III)-Based 9-Metallacrown-3 Complexes Which Exhibit Magnetorefrigerant Properties Chun Y. Chow, Régis Guillot, Eric Rivière, Jeff W. Kampf, Talal Mallah,*, Vincent L. Pecoraro*, Department of Chemistry, University of Michigan, Ann Arbor, MI, 48108, USA Institut de Chemie Moléculaire et des Matériaux d Orsay, CNRS, Université de Paris Sud 11, Orsay Cedex, France

2 Table S1. Crystallographic Details for 1-OBz and 2. 1-OBz 2 mol formula Fe 4 C 45 H 39 N 3 O 18 Fe 8 C H N 6 O fw (g/mol) cryst syst/ space group R-3 R-3 T (K) 85(2) K 100(1) wavelength (Å) a (Å) (20) (9) b (Å) (20) (9) c (Å) (3) (16) α (deg) β (deg) γ (deg) V (Å 3 ) (2) 58691(3) Z 6 18 density, ρ (g/cm 3 ) abs coeff, µ (mm -1 ) F(000) θ range for data collection (deg) to to limiting indices -22 h 2-22 k l h k l 76 reflns collected/ unique 82010/ /13499 completeness to θ (%) no. of data/ restraints/ params 4218/9/ /17/752 goodness of fit on F final R indices R1 a = R1 a = [I > 2σ(I)] WR2 b = WR2 b = R1 a = R1 a = R indices (all data) WR2 b = WR2 b = R1 = Σ( F o F c )/Σ F o. b wr2 = [Σ[w(F 2 o F 2 c ) 2 ]/Σ[w(F ) 2 ]] 1/2 ; w = 1/[σ 2 (F 2 o ) + (mp) 2 + np]; p = [max(f 2 o,0) + 2F 2 c ]/3 (m and n are constants); σ = [Σ[w(F 2 o F 2 c ) 2 ]/(n p)] 1/2. Table S2. Summary of molecular weights obtained by analysis of CHN and TGA data. Compound MW (g/mol) 1-OAc OBz a b c d

3 Figure S1. Experimental PXRD pattern of 1-OAc (black) and simulated pattern (red). Figure S2. Packing diagram of 1-OAc. Hydrogens, coordinating and lattice solvents have been omitted for clarity.

4 Figure S3. PXRD pattern of 1-OBz (black) and simulated pattern (red). Figure S4. Overlaid crystal structures of 1-OAc (blue) and 1-OBz (red). Molecules were tethered at the Fe III sites.

5 Figure S5. Crystal packing of 1-OBz. A pair of adjacent intermolecular dimers. Blue dashed line is the central Fe III central Fe III distance. Green dashed line represents face-to-face π-π stacking. Figure S6. π-π interactions between adjacent intermolecular dimers of 1-OBz. For clarity the phenyl groups engaging in π-interactions are in bold.

6 Figure S7. Possible intermolecular π-π interactions in 2. For each molecule, there exists several potential edge-to-face and face-to-face interactions with neighboring molecules between the aromatic groups from the shi 3- and isopthalate bridging ligands (bolded). Figure S8. Packing diagram of 2 along the c-axis. Solvent channels are ca. 15 Å in diameter.

7 Figure S9. PXRD patterns of compound 2a. Simulated pattern (red), pattern of a fresh sample immersed in mineral oil (black) and an air dried sample (blue).

8 Figure S10. Energy Diagram for the spin states of the Fe 4 9-MC-3 system plotted as E/ J 1 vs. J 2 /J 1. More negative E/ J 1 values are lower in energy. The vertical green dashed line represents the J 2 /J 1 ratio for 1- OAc and the vertical orange dashed line represents the J 2 /J 1 ratio for 1-OBz. The vertical blue dashed line represents the J 2 /J 1 ratio for 2a. The ideal J 2 /J 1 ratio of is represented by the vertical black dasheddotted line.

9 Figure S11. χ m vs. T plot for 1-OBz at a temperature range of 2 to 50 K. Figure S12. M/Nµ B vs. field at temperatures between 3 and 20 K for 1-OAc (open circles), with simulated data (solid lines)

10 Figure S13. M/Nµ B vs. field at temperatures between 2 and 20 K (left) and the temperature-dependent magnetic entropy change for 2a. Figure S14. M/Nµ B vs. field at temperatures between 2 and 20 K (left) and the temperature-dependent magnetic entropy change for 2b.

11 Figure S15. M/Nµ B vs. field at temperatures between 2 and 20 K (left) and the temperaturedependent magnetic entropy change for 2c. Figure S16. M/Nµ B vs. field at temperatures between 2 and 20 K (left) and the temperature-dependent magnetic entropy change for 2d.

12 Estimation of the Molecular Weight of 1-OAc, 1-OBz, 2a, 2b, 2c and 2d A combination of TGA, elemental analysis and PXRD was used to determine the molecular weights of the Fe III complexes. Each compound was analyzed by TGA; the thermolysis of each compound gave a reddish-brown powder that was determined by PXRD (below) to be α-fe 2 O 3 (Hematite). The molecular weight can be determined by TGA through back calculation using the equation: MW = A possible formula was also determined through elemental analysis results. The average MW from the TGA and elemental analysis was used for treating the magnetic data. PXRD patterns for the resultant TGA product of 1-OAc (red), 1-OBz (blue) and 2 (green) and hematite (simulated, black).

13 Compound 1-OAc Elemental analysis results were: C, 33.47; H, 4.60; N, A potential formula derived from the CHN analysis is [Fe 4 (shi 3- ) 3 (acetate - ) 3 (MeOH) 3 ] MeOH 7H 2 O (Fe 4 C 31 H 51 N 3 O 26 ), which gives a MW of g/mol MW back calculated from the TGA is: g/mol The average MW determined is: g/mol TGA trace of 1-OAc.

14 Compound 1-OBz Elemental analysis results were: C, 44.86; H, 4.12; N, A potential formula derived from the CHN analysis is [Fe 4 (shi 3- ) 3 (benzoate - ) 3 (MeOH) 3 ] MeOH 4H 2 O (Fe 4 C 46 H 51 N 3 O 23 ), which gives a MW of g/mol MW back calculated from the TGA is: g/mol The average MW determined is: g/mol TGA trace of 1-OBz.

15 Compound 2a Elemental analysis results were: C, 33.59; H, 4.06; N, A potential formula derived from the CHN analysis is [Fe 8 (shi 3- ) 6 (isopthalate - ) 3 (H 2 O) 6 ] 24H 2 O (Fe 8 C 66 H 96 N 6 O 60 ), which gives a MW of g/mol MW back calculated from the TGA is: g/mol The average MW determined is: g/mol TGA trace of 2a.

16 Compound 2b Elemental analysis results were: C, 39.47; H, 3.25; N, 3.91 A potential formula derived from the CHN analysis is [Fe 8 (shi 3- ) 6 (isopthalate - ) 3 (H 2 O) 6 ] 4H 2 O 2EtOH (Fe 8 C 70 H 70 N 6 O 42 ), which gives a MW of g/mol MW back calculated from the TGA is: g/mol The average MW determined is: g/mol TGA trace of 2b.

17 Compound 2c Elemental analysis results were: C, 39.53; H, 2.81; N, A potential formula derived from the CHN analysis is [Fe 8 (shi 3- ) 6 (isopthalate - ) 3 (H 2 O) 6 ] 4H 2 O EtOH (Fe 8 C 68 H 62 N 6 O 41 ), which gives a MW of g/mol MW back calculated from the TGA is: g/mol The average MW determined is: g/mol TGA trace of 2c.

18 Compound 2d Elemental analysis results were: C, 33.47; H, 4.60; N, A potential formula derived from the CHN analysis [Fe 8 (shi 3- ) 6 (isopthalate - ) 3 (H 2 O) 6 ] H 2 O (Fe 8 C 66 H 50 N 6 O 37 ), which gives a MW of g/mol MW back calculated from the TGA is: g/mol The average MW determined is: g/mol TGA Trace of 2d.