Supplementary Information for Slow Magnetic Relaxation in an Asymmetrically Coupled Heptanuclear Dysprosium(III)-Nickel(II) Architecture

Soumya Mukherjee a, Biplab Joarder a, Shufang Xue b, Jinkui Tang b, **, Sujit K. Ghosh a, * a Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pashan, Pune-411008, India. E-mail: [email protected] b State Key Laboratory of Rare Earth Resource Utilization, Changchun, Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, China. E-mail: [email protected]

Table of Contents

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Scheme 1: Detailed Synthesis Procedures for Compound 1 S2

Figure S1: Coordination polyhedra present in compound 1 S3

Figure S2: Connection modes of ligand in compound 1 S3

Figure S3: Intermetallic distances in compound 1 S4

Figure S4: Intramolecular π-π interactions present in compound 1 S4

Figure S5: Molecular packing diagram of compound 1 along a axis S5

Figure S6: Molecular packing diagram of compound 1 along b axis S6

Figure S7: Molecular packing diagram of compound 1 along c axis S7

Figure S8: PXRD pattern of compound 1 S8

Figure S9: FTIR Spectra of compound 1 S9

Figure S10: Thermogravimetric analysis data of compound 1 S9

Magnetic measurement and X-ray Crystallography details S10

Crystallographic data table S11

References S12

S1 Scheme 1: Detailed synthesis procedures for Compound 1 :

Materials: All reagents and solvents for synthesis and analysis were commercially available and used as received.

Synthesis:

III II Compound [Dy3 Ni4 (L)6(OH)4(CH3OH)3(CH3CN)(NO3)(OH2)]·(CH3CN)3(CH3OH)2(H2O)2 (1):

Triethylamine (0.056 mL, 0.4 mmol) was added to the ligand H2L (0.2 mmol, 42.6 mg) dissolved in methanol/acetonitrile (10 mL/5mL). The reaction mixture was sonicated for 1 h. Solid dysprosium nitrate hexahydrate (0.1 mmol, 45.6 mg) along with addition of nickel nitrate hexahydrate (0.1 mmol, 29 mg), and the resulting yellow solution was stirred for 1 h. The reaction mixture was left unperturbed to allow the slow evaporation of the solvent. Rod-shaped dark greenish-brown single crystals were obtained after one week. Yield: 46 mg, (53%, based on the metal). Anal. Calcd. (found) for C91 H89 N11 O27 Dy3 Ni4: C, 49.08 (49.06); H, 4.68 (4.59); N, 2.58 (2.61).

Similar reactions were put, replacing dysprosium nitrate with gadolinium nitrate, yttrium nitrate and terbium nitrate respectively. Each of these reactions did not yield any crystals but on nearly complete evaporation of the mother liquor, some precipitation resulted, which were of low- crystalline nature (checked by PXRD). Hence, preparation and consequent study of the series of these analogous lanthanide clusters were not possible.

S2 Figure S1: Coordination polyhedra of the three distorted eight-coordinated Dy-centers shown in yellow color and the three distorted octahedral Ni-centers along with the single distinct square-planar Ni center in one side.

Figure S2: Four different coordination modes of ligand L2- in compound 1.

S3 Figure S3: Intermetallic distances (in Å) shown over the dashed green lines.

Figure S4: Intramolecular π-π interactions (shown by green dashed lines: pi-pi) present in the

Dy3Ni4 units of compound 1.

S4 Figure S5: Molecular packing diagram of compound 1 along a axis.

S5 Figure S6: Molecular packing diagram of compound 1 along b axis.

S6 Figure S7: Molecular packing diagram of compound 1 along c axis.

S7 Figure S8: Simulated (Wine) and as-synthesized (Orange) powder X- ray diffraction (PXRD) patterns of compound 1.

S8 Figure S9: FT-IR spectra of compound 1.

Figure S10: Thermogravimetric analysis data of compound 1.

S9 Magnetic measurement details:

Experimental details:

Magnetic measurements were performed in the temperature range 2–300 K using Quantum Design MPMS-XL SQUID and 1.9–5.0 K using SQUID-VSM magnetometers, respectively. The diamagnetic corrections for the compounds were estimated using Pascal’s constants, and magnetic data were corrected for diamagnetic contributions of the sample holder.

X-ray Crystallography details:

Crystal data for the complex: Single-crystal X-ray data of 1 was collected at 200 K on a Bruker KAPPA APEX II CCD Duo diffractometer (operated at 1500 W power: 50 kV, 30 mA) using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å). Crystal was mounted on nylon CryoLoops (Hampton Research) with Paraton-N (Hampton Research). The data integration and reduction were processed with SAINTS1 software. A multi-scan absorption correction was applied to the collected reflections. The structure was solved by the direct method using SHELXTLS2 and was refined on F2 by full-matrix least squares technique using the SHELXL-97S3 program package within the WINGXS4 programme. All non-hydrogen atoms were refined anisotropically. The structure was examined using the Adsym subroutine of PLATONS5 to assure that no additional symmetry could be applied to the models and also to SQUEEZE the CIF to omit the solvent molecules outside the coordination sphere for improved % R factor, PLATON was used. All the details of X-ray crystallographic data along with bond length and bond angles are included in supporting information. CCDC-941834 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. From the Single-crystal X-ray structure (before performing SQUEEZE operation) and the CHNS analysis, the solvent molecules outside the coordination sphere could be assigned as three molecules of CH3CN (acetonitrile), two molecules of CH3OH (methanol) and two molecules of water, mentioned in the formula for compound 1,

III II [Dy3 Ni4 (L)6(OH)4(CH3OH)3(CH3CN)(NO3)(OH2)]·(CH3CN)3(CH3OH)2 (H2O)2.

S10 Table 1. Crystal data and structure refinement for compound 1. Identification code compound 1

Empirical formula C83 H75 Dy3 N8 Ni4 O23 Formula weight 2274.85 Temperature 200(2) K Wavelength 0.71073 Å Crystal system Triclinic Space group P-1 Unit cell dimensions a = 12.046(3) Å α= 99.017(5)°. b = 14.681(4) Å β= 97.022(5)°. c = 28.195(7) Å γ = 98.134(5)°. Volume 4822(2) Å3 Z 2 Density (calculated) 1.567 Mg/m3 Absorption coefficient 3.127 mm-1 F(000) 2246 Crystal size 0.12 x 0.10 x 0.09 mm3 Theta range for data collection 0.74 to 25.00°. Index ranges -14<=h<=14, -17<=k<=17, -33<=l<=33 Reflections collected 69061 Independent reflections 16994 [R(int) = 0.0529] Completeness to theta = 25.00° 99.9 % Absorption correction Semi-empirical from equivalents Max. and min. transmission 0.7661 and 0.7054 Refinement method Full-matrix least-squares on F2 Data / restraints / parameters 16994 / 8 / 1094 Goodness-of-fit on F2 0.869

Final R indices [I>2sigma(I)] R1 = 0.0403, wR2 = 0.0946

R indices (all data) R1 = 0.0581, wR2 = 0.1015 Largest diff. peak and hole 2.134 and -1.637 e.Å-3

S11 References

[S1] SAINT Plus, (Version 7.03); Bruker AXS Inc.: Madison, WI, 2004.

[S2] G. M. Sheldrick, SHELXTL, Reference Manual: version 5.1: Bruker AXS; Madison, WI, 1997.

[S3] G. M. Sheldrick, Acta Crystallogr. Sect. A, 2008, 112.

[S4] WINGX version 1.80.05 Louis Farrugia, University of Glasgow.

[S5] A. L. Spek, PLATON, A Multipurpose Crystallographic Tool, Utrecht University, Utrecht, The Netherlands, 2005.

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