Supporting Information

© Wiley-VCH 2008

69451 Weinheim, Germany

S1

Small Anion, Big Task: Polyoxometalate Supercluster Assembly Mediated by a Single PO4

3–

Xikui Fang and Paul Kögerler* X-ray Crystallographic Structure Determination:

Suitable crystals were coated with Paratone N oil, suspended on a small fiber loop, and placed in a cooled nitrogen stream at 173(2) K on a Bruker D8 SMART APEX CCD sealed-tube diffractometer with graphite-monochromated Mo Kα (0.71073 Å) radiation. A sphere of data was measured using a series of combinations of φ and ω scans with 30 s frame exposures and 0.3° frame widths. The final cell parameters were determined from least-squares refinement on 6587 reflections. Data collection, indexing, and initial cell refinements were all handled using SMART software.[1] Frame integration and final cell refinements were carried out using SAINT software.[2] The SADABS program was used to carry out absorption corrections.[3] The structure was solved using Direct Methods and difference Fourier techniques (SHELXTL, V6.12).[4] All metal and phosphorus atoms were refined anisotropically, except for some of the disordered countercations (K+ and Na+). Scattering factors and anomalous dispersion corrections were taken from the International Tables for X-ray Crystallography.[5] Structure solution, refinement and generation of the crystallographic information file were performed by using SHELXTL, V6.12 software.[4] Not all of the cationic counterions and the lattice water molecules could be located due to disorder. Therefore, thermogravimetric and elemental analysis were used to determine the number of water molecules and countercations, instead. Physical Measurements and Calculations:

Infrared spectra (KBr pellets) were collected on a Bruker Tensor 27 instrument. Atmosphere compensation (CO2 and H2O) and baseline corrections (rubberband method) were carried out after spectrum collections. The 31P NMR spectrum (0.15 mM in D2O) was collected on a Varian VXR-400 MHz instrument. UV absorption measurements were performed on a Shimadzu UV-1650PC spectrometer. Quartz cuvettes with optical path lengths of 1 cm were used. Elemental analysis results (ICP-OES) were obtained from Zentralabteilung für Chemische Analysen (ZCH), Forschungszentrum Jülich, D-52425 Jülich, Germany.

Polycrystalline samples of K36Na111·106H2O were used magnetic properties measurements. The dc magnetic susceptibility was measured at 0.1 Tesla in the temperature range 2 – 290 K using a SQUID magnetometer (MPMS-5, Quantum Design) and corrected for diamagnetic contributions (estimated both from tabulated constants and measurements on diamagnetic polyoxotungstate precursors, χdia(K36Na111·106H2O) = –2.03 × 10–3 emu mol–1). Best-fitting parameters (J, giso) were obtained using a modified version of the MAGPACK program package[6] that employs a Levenberg-Marquardt least-squares minimization mechanism for a predefined range of variables.

For determination of the oxidation states of metal centers and the protonation states of oxygen sites, bond valence sum (BVS) calculations were carried out using the method of I. D. Brown (I. D. Brown, D. Altermatt, Acta Crystallogr. Sect. B 1985, 41, 244). The ro values were taken from the literature for calculations performed on Mn,[7] Ce[8] and O[6–9] (Table S2). [1] SMART Version 5.628, 2003, Bruker AXS, Inc., Analytical X-ray Systems, 5465 East Cheryl Parkway, Madison WI

53711-5373. [2] SAINT Version 6.36A, 2002, Bruker AXS, Inc., Analytical X-ray Systems, 5465 East Cheryl Parkway, Madison WI

53711-5373. [3] SADABS Version 2.08, 2003, George Sheldrick, University of Göttingen. [4] SHELXTL 6.12, 2002, Bruker AXS, Inc., Analytical X-ray Systems, 5465 East Cheryl Parkway, Madison WI 53711-5373. [5] A. J. C. Wilson (ed), International Tables for X-ray Crystallography, Volume C. Kynoch, Academic Publishers, Dordrecht,

1992, Tables 6.61.1.4 (pp. 500−502) and 4.2.6.8 (pp. 219−222). [6] J. J. Borrás-Almenar, J. M. Clemente-Juan, E. Coronado and B. S. Tsukerblat, J. Comput. Chem., 2001, 22, 985. [7] W. Liu, H. H. Thorp, Inorg. Chem. 1993, 32, 4102. [8] P. L. Roulhac, G. J. Palenik, Inorg. Chem. 2003, 42, 118. [9] N. E. Brese, M. O’Keeffe, Acta Crystallogr. Sect. B 1991, 47, 192.

S2

Figure S1. 31P NMR spectrum of a solution of K36Na111·106H2O in D2O (0.15 mM).

Figure S2. IR spectra (KBr pellet) of K36Na111·106H2O and 2.

S3

Figure S3. Structural comparison of the {Ce3Mn2} cluster cores in 2 (left) and 1 (right) showing the distortion associated with ligand exchange. The idealized local symmetries are D3h and C2 for the Ce3Mn2 cores in 2 and 1, respectively.

* Distance and angle data of 2 from: A. J. Tasiopoulos, P. L. Milligan, Jr., K. A. Abboud, T. A. O’Brien, G. Christou, Inorg. Chem. 2007, 46, 9678. Table S1. Selected interatomic distances and bond angles for the {Ce3Mn2} core in 2 and the dimeric units of 1. See Figure S3 for the numbering. (The Ce, Mn and O sites in Figure S3 are re-numbered for the convenience of comparison and their numbering is different from that used in the crystallographic information files.)

1 Distance (Å) 2* dimer A dimer B/B’ Mn1···Ce1 3.220 3.423 3.501 Mn1···Ce2 3.232 3.074 3.033 Mn1···Ce3 3.228 3.630 3.569 Mn2···Ce1 3.228 3.423 3.485 Mn2···Ce2 3.201 3.630 3.519 Mn2···Ce3 3.223 3.074 3.072 Ce1···Ce2 3.753 4.083 3.991 Ce1···Ce3 3.742 4.083 4.082 Ce2···Ce3 3.749 3.835 3.838 Mn1···Mn2 4.775 4.943 4.936

1 Angle (º) 2* dimer A dimer B/B’ Mn1–O1–Ce1 101.0 115.8 117.1 Mn1–O1–Ce2 101.8 93.7 92.6 Mn1–O2–Ce2 101.5 93.3 92.4 Mn1–O2–Ce3 101.2 126.9 123.0 Mn1–O3–Ce3 101.9 87.5 89.5 Mn1–O3–Ce1 101.4 92.9 90.8 Mn2–O4–Ce1 101.7 92.9 91.8 Mn2–O4–Ce2 101.4 87.5 88.7 Mn2–O5–Ce2 101.9 126.9 124.3 Mn2–O5–Ce3 101.3 93.3 90.0 Mn2–O6–Ce3 101.9 93.7 91.2 Mn2–O6–Ce1 102.2 115.8 123.0 Mn1–O7–Ce2 87.1 89.3 Mn2–O8–Ce3 87.1 86.0

S4

Table S2. Bond valence sum (BVS) analysis for metal centers of the {Ce3Mn2} cores and selected oxygen sites of polyoxoanion complex 1. The assigned oxidation states and protonated states are highlighted in bold and shaded. (Dimer A and dimer B/B’ are of opposite configuration. Dimer A resides on a C2 axis while B/B’ has no crystallographically imposed symmetry.)

BVS[6]

Mn(II) Mn(III) Mn(IV) Mn1 4.39 4.02 4.22 Mn2 4.19 3.86 4.03 Mn3 4.17 3.81 4.00

BVS[7]

Ce(III) Ce(IV) a-Ce1 4.79 4.15 b-Ce2 4.32 3.74 b-Ce3 4.45 3.86 b-Ce4 4.61 4.00 a-Ce5 4.64 4.02

Oxygen atom BVS[6–8]

Assigned protonation state

Dimer A μ4-O50 1.88 O μ3-O169 1.66 O μ2-O170 1.00 OH μ3-O171 1.49 O Dimer B μ4-O106 1.98 O or dimer B’ μ4-O162 1.86 O μ3-O174 1.68 O μ3-O175 1.73 O μ2-O176 0.99 OH μ3-O177 1.99 O μ3-O178 1.91 O μ2-O179 1.05 OH Inter-dimer μ2-O147 1.97 O bridging μ2-O172 1.75 O and others μ2-O173 1.93 O μ2-O180 0.79 OH μ2-O181 1.07 OH μ-O1W 0.28 OH2

dimer A dimer B/B’

mirror

Λ Δ

S5

Figure S4. A wireframe representation of K36Na111·106H2O illustrating the intramolecular hydrogen bonding interactions between the dimeric building blocks. D···A distances (Å): O1W···O53, 2.595; O1W···O171, 2.823; O179···O93, 2.747; O1W’···O53’, 2.595; O1W’···O171’, 2.823; O179’···O93’, 2.747 Å.

Figure S5. TGA and simultaneous DTA diagrams of K36Na111·106H2O (10 K/min, 60 ml N2/min).

S6

Figure S6. UV spectra of K36Na111·106H2O and 2 in H2O. The concentrations are 1.97×10–6 mol/L and 2.25×10–5 mol/L for K36Na111·106H2O and 2, respectively.

Figure S7. Packing diagram of K36Na111·106H2O visualized along the crystallographic b (left) and c axis (right), highlighting the dimension of the unit cell. The countercations and the solvent H2O molecules have been omitted for clarity. The polyoxoanions are tightly packed in the crystal lattice and no intermediate pores or channels are observed.