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Article Cite This: Inorg. Chem. XXXX, XXX, XXX−XXX

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Thorium(IV) and Uranium(IV) Complexes with Cucurbit[5]uril Yingjie Zhang,*,† Mohan Bhadbhade,§ Maxim Avdeev,† Jason R. Price,‡ Inna Karatchevtseva,† Qing Li,⊥ Zhu Tao,⊥ and Gang Wei# †

Australian Nuclear Science and Technology Organization, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia Mark Wainwright Analytical Centre, University of New South Wales, Kensington, NSW 2052, Australia ‡ Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia ⊥ Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province, Guizhou University, Guiyang, Guizhou 550025, P. R. China # CSIRO Manufacturing, PO Box 218, Lindfield, NSW 2070, Australia

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S Supporting Information *

ABSTRACT: Tetravalent thorium and uranium complexes with cucurbit[5]uril (Q[5]) were investigated with eight new complexes being synthesized and structurally characterized. [Th(Q[5])(OH)(H2O)2]6·18NO3·nH2O (1) has a hexagonal nanowheel structure with each of the six Th4+ ions being capcoordinated by a Q[5] and monodentate-coordinated to the nearby Q[5]. [Th(Q[5])(HCOO)(H2O)4][Th(NO3)5(H2O)2]2[Th(NO3)3(HCOO)(H2O)2]0.5·NO3·nH2O (2) has a heteroleptic mononuclear structure with a Th4+ ion cap-coordinated on one side of the Q[5] portal and monodentate-coordinated to a formate anion inside the Q[5] cavity. [KTh1.5(Q[5])Cl(NO3)3][Th(NO3)5(H2O)2]·2NO3·2.5H2O (3) has a heterometallic structure with both Th4+ and K+ ions each occupying one side of the two Q[5] portals forming a capsule. [CsTh(Q[5])Cl(NO3)2(H2O)3]·2NO3·nH2O (4) has a heterometallic 1D polymeric structure with both Th4+ and Cs+ ions each occupying one side of the two Q[5] portals, forming monomers which are linked together by sharing two water molecules and one carbonyl oxygen atom between Th4+ and Cs+ ions. [Th(Q[5])Cl(H2O)][CdCl3][CdCl4]·0.5HCl·4H2O (5), [Th(Q[5])Cl(H2O)][Ru2OCl9(H2O)]·0.5HCl·9.5H2O (6), [Th(Q[5])Cl(H2O)][IrCl6]1.5·3H2O (7), and [U(Q[5])Cl(H2O)][ZnCl3(H2O)][(ZnCl4)]·8H2O (8) have similar 1D polymeric structures with Th4+/U4+ ions cap-coordinated on one side of a Q[5] and bidentate coordinated to the nearby Q[5]. The transition metal chlorides act as anions for charge compensation as well as structure inducers via cation−anion interactions forming various anion patterns around the 1D polymers. Actinide contraction has been observed in the early actinide series.

1. INTRODUCTION

closely arranged portal carbonyl oxygen atoms which can often form stable metal complexes through metal cap coordination by all five oxygen atoms.5a Despite the recent advances on the structure chemistry of uranyl(VI) [(UO2)2+] ion with Q[5− 8],6 tetravalent actinide ion complexes with Q[n] have been much less studied with only two discrete structures reported so far, both for Q[6] with thorium (Th4+) ion,7 one with two Th4+ ions on each side of the portals of Q[6] making it a dinuclear Th4+ complex,7a and the other with only second shell interactions between hydrated Th4+ species and Q[6].7b To the best of our knowledge, no other tetravalent actinide ions or any other structure type of Th4+ ion with Q[n] has been reported. Literature survey clearly demonstrated that the structural chemistry of Q[n] with tetravalent actinide ions is in need of developing, which was the prime motivation for us to take on the current work. Herein, we report the first systematic

The cucurbit[n]urils (Q[n]s) each contain a rigid hydrophobic macrocyclic cavity accessible via the two identical opposite portals rimmed with carbonyl groups.1 The pumpkin-shaped structures can incorporate suitable guest molecules via host− guest and noncovalent interactions in their central cavities for catalysis reactions and selective molecular recognitions.2 Their complexes with alkali and alkaline earth metal ions have been well-documented,3 while complexes with selected transition metal ions are also available.4 In the past decade, the coordination chemistry of Q[n] with lanthanide(III) (Ln3+) ions has been extensively studied,5 greatly inspired by the fact that Q[n] can form slightly different structures with Ln3+ ions, suggesting the potential of using Q[n] for lanthanide separations.5k Contrary to larger Q[n]s with rich host−guest chemistries, Q[5] as the smallest member of Q[n] family has relatively smaller portal size which reduces the possibility of forming host−guest complexes. However, Q[5] offers two sets of five © XXXX American Chemical Society

Received: May 17, 2018

A

DOI: 10.1021/acs.inorgchem.8b01347 Inorg. Chem. XXXX, XXX, XXX−XXX

Article

Inorganic Chemistry study on the structures of eight Q[5] complexes with Th4+/U4+ ions via direct complexation and supramolecular assembly in neutral or acidic aqueous solutions. The successful preparation of similar polymeric Th4+ and U4+ complexes with Q[5] also provides the opportunity to compare directly the coordination of Q[5] to tetravalent actinides in the early actinide series.

474s, 438m, 406m, 364m, 282s, 262vs, 208m, 180m, 131m. UV−vis (solid state λmax, nm): 210s, 227s, 298w, 372vw, 455vw. 2.1.6. Synthesis of [Th(Q[5])Cl(H2O)][Ru2OCl9(H2O)]·0.5HCl· 9.5H2O (6). Q[5]·12H2O (20 mg, 0.02 mmol) was dissolved in 5.0 mL HCl solution (6 M) in a 20 mL glass vial followed by adding 0.2 mL of thorium nitrate solution (0.5 M) and ruthenium chloride (20 mg, 0.1 mmol) in 5.0 mL HCl solution (6 M). Dark brown crystalline product of 6 was formed after slow evaporation with ∼75% yield (28 mg) based on Q[5]. Elemental analysis (%) (calcd, found) for C30H53.5N20O22.5Cl10.5Ru2Th: C (19.36, 19.27), H (2.90, 3.08), N (15.05, 15.16). FTIR (cm−1): 1758s, 1732w, 1704s, 1685w, 1647s, 1512vs, 1454m, 1414m, 1384vs, 1333vs, 1291m, 1237s, 1191vs, 1142m, 957vs, 810vs, 794s, 761s, 686m. UV−vis (solid state λmax, nm): 252w, 359s, 475s, 734s. 2.1.7. Synthesis of [Th(Q[5])Cl(H2O)][IrCl6]1.5·3H2O (7). Q[5]· 12H2O (20 mg, 0.02 mmol) was dissolved in 5.0 mL of HCl solution (6 M) in a 20 mL glass vial followed by adding 0.2 mL of thorium nitrate solution (0.5 M) and iridium chloride (30 mg, 0.1 mmol) in 4.0 mL of HCl solution (6 M). Dark brown crystalline product of 7 was formed after slow evaporation for a few weeks with very low yield. Limited characterizations have been done, including SEM-EDS, UV− vis, PXRD, FTIR, and single crystal X-ray diffraction. FTIR (cm−1): 1758s, 1732w, 1704s, 1685w, 1647s, 1512vs, 1454m, 1414m, 1384vs, 1333vs, 1291m, 1237s, 1191vs, 1142m, 957vs, 810vs, 794s, 761s, 686m. UV−vis (solid state λmax, nm): 230s, 315w, 380s, 460s, 620w. 2.1.8. Synthesis of [U(Q[5])Cl(H2O)][ZnCl3(H2O)][(ZnCl4)]·8H2O (8). Q[5]·12H2O (20 mg, 0.02 mmol) was dissolved in 5.0 mL of HCl solution (6 M) in a 20 mL glass vial followed by adding 0.2 mL of uranyl nitrate solution (0.5 M). Zinc metal (∼500 mg) was added, allowing the reduction reaction for 5 min. Clear light pink solution was obtained after Zn metal was removed, and the glass vial was sealed with paraffin film. Light gray colored crystals of 8 was obtained from the solution after a few days with ∼84% yield (∼28 mg) based on Q[5]. Elemental analysis (%) (calcd, found) for C30H50N20O20Cl8Zn2U: C (21.66, 21.52), H (3.03, 3.18), N (16.84, 16.75). Raman (514 nm laser, cm−1): 1756s, 1666m, 1646m, 1414s, 1398m, 1374s, 1318w, 1263w, 1199m, 1129w, 1026w, 1008w, 963w, 928w, 891w, 838vs, 793w, 752s, 675w, 649w, 472s, 437w, 364w, 284vs, 242m, 180s. UV−vis−NIR (solid state, λmax, nm): 230s, 285w, 315w, 365s, 430s, 465s, 552w, 638w, 655w, 675w. 2.2. Single Crystal and Powder X-ray Diffraction Studies. Single crystal data for 1−7 were collected on the MX beamlines at the Australian Synchrotron at 100 K using an energy equivalent to Mo Kα radiation (17.446 Kev, λ = 0.71074 Å). Data collection was controlled using the BlueIce software package.9 Data indexing and integration were conducted using the program XDS.10 Single crystal data for 8 was collected on a Bruker kappa-II CCD diffractometer at 150 K by using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å). Symmetry related absorption corrections using the program SADABS were applied, and the data were corrected for Lorentz and polarization effects using Bruker APEX2 software.11 All structures were solved by direct methods using SHELXT12 and refined with SHELXL-201413 via Olex2 interface.14 The structure refinements were difficult due to some anion and lattice water disorders. In general, nonhydrogen atoms were refined with anisotropic displacement parameters with some exceptions in instances of disorders. Hydrogen atoms attached to carbon and water molecules with full occupancies were generally placed in calculated positions and refined using a riding model. Potential hydrogen bonds were calculated using PLATON.15 Powder X-ray diffraction (PXRD) data were collected at room temperature using a Bruker D8 Focus diffractometer equipped with Cu Kα (λ = 1.5418 Å) radiation. Data were collected in the angle interval 2θ = 5−50° with a step size of 0.02°. 2.3. Scanning Electron Microscopy (SEM)/Energy-Dispersive X-ray Spectroscopy (EDS). A Zeiss Ultra Plus SEM (Carl Zeiss NTS GmbH, Oberkochen, Germany) operating at 15 kV equipped with an Oxford Instruments X-Max 80 mm2 SDD X-ray microanalysis system was used to check the crystal morphologies and determine the presence of key elements.

2. EXPERIMENTAL SECTION Caution! Thorium nitrate tetrahydrate [Th(NO3)4·4H2O] and uranyl nitrate hexahydrate [UO2(NO3)2·6H2O] contain natural thorium and uranium. Their compounds are radioactive, and standard precautions for handling these hazardous materials must be followed. 2.1. Materials and Synthesis. Thorium nitrate tetrahydrate [Th(NO3)4·4H2O] and uranyl nitrate hexahydrate [UO2(NO3)2· 6H2O] were from International Bioanalytical Industries, Inc. The Q[5] (C30H30N20O10) was prepared as reported.8 Other chemicals in reagent grade were from Sigma-Aldrich and used without further purification. 2.1.1. Synthesis of [Th(Q[5])(OH)(H2O)2]6·18NO3·nH2O (1). Q[5]· 12H2O (10 mg, 0.01 mmol), 0.1 mL of thorium nitrate solution (0.5 M), and 4 mL of deionized (DI) water were added in a 20 mL glass vial. Colorless large crystals of 1 were formed after evaporation for 3 weeks when the solution is nearly dry with a very low yield, allowing only limited characterizations including SEM-EDS, Raman, and single crystal X-ray diffraction. Raman (514 nm laser, cm−1): 1754w, 1659w, 1500w, 1418m, 1376m, 1327w, 1259w, 1190w, 1125w, 1041vs, 961w, 889m, 835s, 754s, 651w, 466m, 365w, 245m. 2.1.2. Synthesis of [Th(Q[5])(HCOO)(H2O)4][Th(NO3)5(H2O)2]2[Th(NO3)3(HCOO) (H2O)2]0.5·NO3·nH2O (2). Q[5]·12H2O (10 mg, 0.01 mmol), 0.1 mL of thorium nitrate solution (0.5 M), 0.5 mL formic acid, and 4 mL of DI water were added in a 20 mL glass vial. Colorless fine crystalline product of 2 was formed after evaporation for 3 weeks with a low yield, allowing only limited characterizations, including SEM-EDS, Raman and single crystal X-ray diffraction. Raman (514 nm laser, cm−1): 1768w, 1617w, 1554m, 1417m, 1377m, 1320w, 1199w, 1125w, 1036vs, 960w, 890m, 1102w, 835s, 750s, 709w, 681w, 469m, 364w, 284w, 246m. 2.1.3. Synthesis of [KTh1.5(Q[5])Cl(NO3)3][Th(NO3)5(H2O)2]·2NO3· 2.5H2O (3). Q[5]·12H2O (10 mg, 0.01 mmol), 0.1 mL of thorium nitrate solution (0.5 M), 0.1 mL potassium nitrate solution (0.5 M), and 0.5 mL HCl solution (6 M) were added in a 20 mL glass vial with 5.0 mL of DI water. The colorless solution was allowed to evaporate. White crystalline product of 3 was obtained after several weeks with a low yield. Limited characterizations were done, including SEM-EDS, Raman, and single crystal X-ray diffraction. Raman (514 nm laser, cm−1): 1766w, 1623w, 1546w, 1498w, 1416w, 1379w, 1358w, 1196w, 1048vs, 890w, 834m, 754w, 714w, 469w, 271w. 2.1.4. Synthesis of [CsTh(Q[5])Cl(NO3)2(H2O)3]·2NO3·nH2O (4). Q[5]·12H2O (10 mg, 0.01 mmol), 0.1 mL of thorium nitrate solution (0.5 M), 0.1 mL of cesium nitrate solution (0.5 M), and 0.5 mL of HCl solution (6 M) were added in a 20 mL glass vial with 5.0 mL of DI water. White crystalline product of 4 was obtained after several weeks with a low yield. Only limited characterizations were done including SEM-EDS, Raman, and single crystal X-ray diffraction. Raman (514 nm laser, cm−1): 1755w, 1720w, 1543w, 1504w, 1419m, 1381w, 1333w, 1263w, 1213w, 1195w, 1124w, 1142vs, 961w, 990w, 834s, 788w, 750s, 713w, 619w, 470m, 437w, 366w, 283m, 245m. 2.1.5. Synthesis of [Th(Q[5])Cl(H2O)][CdCl3][CdCl4]·0.5HCl·4H2O (5). Q[5]·12H2O (20 mg, 0.02 mmol) was dissolved in 5.0 mL of HCl solution (6 M) in a 20 mL glass vial followed by adding 0.2 mL of thorium nitrate solution (0.5 M) and cadmium nitrate tetrahydrate (32 mg, 0.1 mmol) in 5 mL HCl solution (6 M). White crystalline product of 5 was formed after a few days with ∼68% yield (23 mg) based on Q[5]. Elemental analysis (%) (calcd, found) for C30H38.5N20O15Cl8.5Cd2Th: C (21.48, 21.25), H (2.31, 2.46), N (16.70, 16.52). Raman (514 nm laser, cm−1): 1760w, 1693w, 1672w, 1649w, 1466w, 1425s, 1375s, 1334w, 1319w, 1270w, 1210m, 1196m, 1136w, 960m, 928w, 893s, 839vs, 792w, 750s, 692w, 674w, 622w, B


Article

Inorganic Chemistry Table 1. Crystal Data and Refinement Details for Complexes 1−8 complex

1

2

3

4

formula formula weight crystal system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) volume (Å3) Z/μ (mm−1) min./max. θ (o) dcalcd (g cm−3) GOF final R1a [I > 2σ(I)] final wR2b [I > 2σ(I)] complex

C90H106N60O43Th3 3412.46 triclinic P1̅ 18.310(4) 19.060(4) 22.000(4) 98.39(3) 96.86(3) 92.50(3) 7527(3) 2/3.047 0.943/25.000 1.506 1.042 0.0504 0.1285 5

C63H70N55.5O85Th4.5 4008.92 triclinic P1̅ 13.620(3) 15.910(3) 18.260(4) 76.56(3) 89.22(3) 67.94(3) 3554.8(15) 1/4.814 1.597/25.999 1.873 1.032 0.0604 0.1662 6

C30H36N29.5O47.50ClKTh2.5 2224.53 triclinic P1̅ 13.535(3) 15.788(3) 18.398(4) 74.92(3) 88.98(3) 69.20(3) 3536.4(15) 2/5.470 2.059/30.067 2.089 1.032 0.0557 0.1652 7

C30H32N27.25O38.75ClCsTh2 2026.77 monoclinic P21/n 13.503(3) 25.605(5) 17.237(3) 90 92.14(3) 90 5955(2) 4/5.764 1.425/24.999 2.260 1.037 0.0651 0.1685 8

formula formula weight crystal system space group a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) volume (Å3) Z/μ (mm−1) min./max. θ (o) dcalcd (g cm−3) GOF final R1a [I > 2σ(I)] final wR2b [I > 2σ(I)]

C30H37N20O15Cl8.5Cd2Th 1675.96 monoclinic P21/c 13.893(3) 24.155(5) 16.853(3) 90 112.74(3) 90 5216(2) 4/4.169 1.799/30.080 2.134 1.058 0.0491 0.1286

C30H38N20O22.5Cl11Ru2Th 1846.93 monoclinic P21/c 13.478(3) 24.648(5) 17.151(3) 90 93.44(3) 90 5687(2) 4/3.741 1.448/24.999 2.157 1.049 0.0387 0.0987

C30H30N20O14Cl10Ir1.5Th 1769.58 monoclinic P21/m 14.755(3) 25.037(5) 16.976(3) 90 94.59(3) 90 6251(2) 4/6.056 1.385/27.927 1.880 1.085 0.0870 0.2461

C30H46N20O20Cl8.25Zn2U 1660.10 monoclinic P21/n 13.8321(11) 16.7980(11) 23.3946(18) 90 93.109(5) 90 5427.8(7) 4/4.349 2.577/25.000 2.032 1.023 0.0438 0.0987

R1 = ∑∥Fo| − |Fc∥/|Fo|. bwR2 = (∑[w(F02 − Fc2)2]/∑[w(F02)2])1/2.

a

2.4. Raman and IR Spectroscopy. Raman spectra were recorded on a Renishaw inVia spectrometer equipped with a 514 nm excitation Ar laser in the range of 2000−100 cm−1 with a spectral resolution of ∼1.7 cm−1. Fourier transfer infrared (FTIR) data were obtained on a Nicolet Nexus 8700 FTIR spectrophotometer. The samples were grounded to powders and diluted in dried KBr and pressed into pellets for acquisition of the IR spectra. The spectra were collected by averaging 1024 scans in the 4000−650 cm−1 range with a nominal resolution of 4 cm−1. 2.5. UV−Vis Absorption Spectroscopy. Absorption spectra were collected on an Agilent Cary 5000 spectrophotometer equipped with a Labsphere Biconical Accessory. Spectra were referenced to that of a Labsphere certified standard (Spectralon) and transformed into Kubelka−Munk units, F(R) = (1 − R)2/2R.16 2.6. Magnetic Susceptibility. Magnetic susceptibility data for complex 8 were collected using a PPMS9 magnetometer (Quantum Design) calibrated against a standard palladium sample. Zero-field cooled DC susceptibility was measured under the field of 1000 Oe in the range 2−300 K. The data were corrected for diamagnetism using the Pascal’s constants.

approach are 1) Q[n]s are very stable in acidic solutions; 2) HCl will aid the formation of various transition metal chloride species to facilitate the crystallization of Q[n] complexes with Ln3+ ions via cation−anion interactions. Although there is no report of any Q[5] complex with Th4+/U4+ ions in the literature, two Q[6] complexes with Th4+ ions had been previously synthesized, a dinuclear complex7a formed by the reaction of Q[6] with ThCl4 in 1 M HCl solution and a Q[6] complex via second-shell interactions7b with [Th(NO3)(H2O)8]3+ species formed under hydrothermal conditions at 180 °C. Instead, a synthesis strategy with a broader scope (reactions in both neutral and acidic solutions as well as the addition of either alkali or transition metal ions) has been adopted in the current study in the pursuit for the Q[5] complexes with Th4+/U4+ ions. The reaction of Q[5] with thorium nitrate in DI water leads to the formation of complex 1. The same reaction in a dilute formic acid solution leads to the formation of complex 2, while the reactions in 6 M HCl solution with the addition of either K+/Cs+ ions facilitate the formations of heterometallic complexes 3 and 4 or CdCl2/ RuCl3/IrCl3 as structure inducers to form complexes 5−7. In addition, the in situ reduction of (UO2)2+ to U4+ ions with Zn metal in a 6 M HCl solution containing Q[5] leads to the

3. RESULTS AND DISCUSSION 3.1. Synthesis Strategy. In general, the synthesis of Q[n] complexes with Ln3+ ions is dominated by the direct reactions in HCl solutions.5 Two obvious reasons attributed to this C


Article

Inorganic Chemistry Table 2. Bond Lengths (Å) of Metal Coordination Environments for Complexes 1−4 complex 1 Th1−O1 Th1−O2W Th1−O4 Th2−O4W Th2−O10 Th2−O13 Th3−O7W Th3−O18 Th3−O28

2.516(5) 2.505(4) 2.524(5) 2.116(4) 2.573(4) 2.564(4) 2.137(4) 2.567(4) 2.499(5)

Th1−O1W Th1−O3 Th1−O5 Th2−O5W Th2−O11 Th2−O14 Th3−O8W Th3−O26 Th3−O29

2.119(4) 2.508(5) 2.561(4) 2.489(5) 2.515(5) 2.521(5) 2.516(5) 2.549(5) 2.476(5)

Th1−O2 Th1−O3W Th1−O21 Th2−O6W Th2−O12 Th2−O15 Th3−O9W Th3−O27 Th3−O30

2.505(5) 2.457(5) 2.552(4) 2.464(5) 2.530(5) 2.504(5) 2.456(5) 2.543(6) 2.511(5)

2.297(6) 2.455(7) 2.491(6) 3.028(7)

Th1−O1W Th1−O6 Th1−O9

2.500(7) 2.531(6) 2.521(6)

2.509(5) 2.469(6) 2.512(5) 3.027(6) 2.520(12) 2.580(15) 2.619(12) 2.567(13) 2.751(8) 2.734(8)

Th1−O1W Th1−O3 Th1−O11 Th3−O7W Th3−O30 Th3−O35 Th3−O39 K1−O3W K1−O7 K1−O10

2.514(6) 2.506(6) 2.611(5) 2.437(16) 2.589(15) 2.584(14) 2.608(12) 2.844(10) 2.732(6) 2.806(6)

2.552(11) 2.613(9) 2.568(10) 2.447(14) 2.424(8) 2.432(7) 2.524(7) 3.144(8) 3.189(12) 3.068(7) 3.416(7)

Th1−O1C Th1−O1W Th1−O2C Th1−O3W Th2−O5W Th2−O7 Th2−O10 Cs1−O3 Cs1−O4 Cs1−O5W

2.523(14) 2.399(13) 2.566(11) 2.52(3) 2.504(7) 2.471(7) 2.466(7) 2.984(7) 2.914(7) 3.225(8)

complex 2 Th1−O1A Th1−O2A Th1−O7 Th1−O10

2.572(6) 2.614(7) 2.523(6) 2.535(7)

Th1−O1AA Th1−O2W Th1−O8 Th1−N1A complex 3

Th1−Cl1 Th1−O2 Th1−O4 Th1−O12 Th3−O8AW Th3−O32 Th3−O36 Th3−O41 K1−O4W K1−O8 K1−O31

2.782(2) 2.464(5) 2.501(6) 2.586(6) 2.532(17) 2.585(12) 2.626(13) 2.565(12) 2.99(2) 2.754(7) 3.012(14)

Th1−O1 Th1−O2W Th1−O5 Th1− N21 Th3−O29 Th3−O33 Th3−O38 Th3−O42 K1−O6 K1−O9

Th1−O1A Th1−O1D Th1−O2A Th1−O2D Th2−Cl1 Th2−O6 Th2−O8 Cs1−O1 Cs1−O3E Cs1−O4W Cs1−O3AA

2.554(11) 2.57(3) 2.589(12) 2.57(3) 2.759(3) 2.519(7) 2.460(7) 3.361(8) 3.149(9) 3.434(10) 3.106(8)

Th1−O1B Th1− O1E Th1−O2B Th1−O2W Th2−O4W Th2−O6W Th2−O9 Cs1−O2 Cs1−O3I Cs1−O5 Cs1−O9

complex 4

formation of complex 8. Consequently, eight solid complexes have been successfully isolated and structurally investigated. 3.2. Crystal Structure Descriptions. The crystal data and structural refinement details for complexes 1−8 are summarized in Table 1, selected bond lengths and angles are listed in Tables 2 and 3, and the potential hydrogen bonds are listed in Table S1, Supporting Information. The direct reaction of thorium nitrate with Q[5] in DI water leads to the formation of complex 1 with a unique hexagonal nanowheel structure (Figure 1). Each Th4+ ion is 9-fold coordinated with a cap coordination to one Q[5] and monodentate coordination to another [2.499(5)−2.567(4) Å for Th−O(CO)], together with two coordinated water molecules [2.456(5)−2.516(5) Å for Th−O(H2O)] and one hydroxyl group [2.116(4)− 2.137(4) Å for Th−O(OH)] internally coordinated inside the Q[5] cavity. The hexagonal nanowheel has the nearly perfect shape with Th−Th distances ranging from 9.670(6) to 9.700(6) Å and Th−Th−Th angles from 119.37° to 120.33° (Figure 1c), very close to the ideal value of 120°. The size of the hexagonal nanowheel is ∼30.295(6) Å [∼3.03(1) nm] measured by the distance from the most separated H atoms on

the hexagonal nanowheel (Figure S1a, Supporting Information). Both coordinated and lattice water molecules are hydrogen bonding to the carbonyl O atoms of the Q[5] ligands (Figure S1b, Table S1, Supporting Information), and the hexagonal nanowheels are packed along the crystallographic b-axis (Figure S1c, Supporting Information). The reaction of thorium nitrate with Q[5] in a dilute formic acid solution leads to the formation of a discrete complex 2 (Figure 2). It has a mononuclear structure with one Th4+ ion cap-coordinated by the five carbonyl O atoms on one side of the Q[5] portal, together with two water molecules and a bidentate nitrate anion externally coordinated and a monodentate formate anion internally coordinated inside the Q[5] cavity, making a 10-fold coordination geometry for the Th4+ center. [Th(NO3)5(H2O)2]− and disordered Th4+ nitrate species are found in the crystal lattice for charge balancing. The 10 Th−O bonds vary significantly, from the shortest 2.298(6) Å for Th−O(HCOO), to 2.454(7)−2.499(7) Å for Th−O(H2O), 2.492(6)−2.535(7) Å for Th−O(CO), to the longest 2.572(6)−2.615(7) Å for Th−O(NO3) bonds. Hydrogen bonds among coordinated nitrate, water, and carbonyl O D


Article

Inorganic Chemistry Table 3. Bond Lengths (Å) of Metal Coordination Environments for Complexes 5−8 complex 5 Th1−Cl1 Th1−O2 Th1−O8 Cd1−Cl2 Cd1−Cl5 Cd2−Cl6 Cd2−Cl9A Cd2−Cl0A

2.7577(13) 2.394(4) 2.454(4) 2.4740(14) 2.4611(16) 2.4349(17) 2.512(4) 2.280(4)

Th1−O1 Th1−O6 Th1−O9 Cd1−Cl3 Cd2−Cl6 Cd2−Cl7A Cd2−Cl9A′

2.440(3) 2.465(4) 2.488(3) 2.4450(13) 2.4351(15) 2.426(3) 2.653(5)

Th1−O1W Th1−O7 Th1−O10 Cd1−Cl4 Cd2−Cl7A Cd2−Cl8A Cd2−Cl7B

2.406(4) 2.494(4) 2.463(4) 2.4634(12) 2.424(3) 2.570(4) 2.516(5)

2.408(4) 2.471(4) 2.462(4) 2.3276(17) 1.785(4) 2.3430(18) 2.3849(16)

Th1−O1W Th1−O7 Th1−O10 Ru1−Cl4 Ru1−O12 Ru2−Cl8 Ru2−O11

2.434(4) 2.488(4) 2.490(3) 2.3226(17) 2.146(4) 2.3215(18) 1.782(4)

2.419(10) 2.459(11) 2.411(18) 2.476(13) 2.337(4) 2.314(5) 2.312(5)

Th1−O1W Th1−O12 Th2−O4 Th2−O7 Ir1−Cl5 Ir1−Cl8 Ir2−Cl11

2.426(15) 2.512(14) 2.456(9) 2.412(9) 2.315(4) 2.337(5) 2.332(6)

U1−O1W U1−O7 U1−O10 Zn1−Cl3 Zn2−Cl6

2.380(5) 2.399(5) 2.450(5) 2.283(2) 2.257(2)

complex 6 Th1−Cl1 Th1−O2 Th1−O8 Ru1−Cl2 Ru1−Cl5 Ru2−Cl6 Ru2−Cl9

2.7588(15) 2.461(4) 2.439(3) 2.3875(16) 2.3489(16) 2.3744(17) 2.3357(16)

Th1−O1 Th1−O6 Th1−O9 Ru1−Cl3 Ru1−O11 Ru2−Cl7 Ru2−Cl10

Th1−Cl2 Th1−O10 Th2−Cl1 Th2−O5 Ir1−Cl3 Ir1−Cl6 Ir2−Cl9

2.729(5) 2.464(9) 2.735(5) 2.450(9) 2.336(4) 2.343(4) 2.333(4)

Th1−O1 Th1−O11 Th2−O2W Th2−O6 Ir1−Cl4 Ir1−Cl7 Ir2−Cl10

complex 7

complex 8 U1−Cl8 U1−O2 U1−O8 Zn1−Cl1 Zn1−Cl4 Zn2−Cl7

2.6919(17) 2.375(5) 2.452(5) 2.268(2) 2.264(2) 2.229(2)

U1−O1 U1−O6 U1−O9 Zn1−Cl2 Zn2−Cl5 Zn2−O3W

2.385(5) 2.463(5) 2.430(5) 2.244(2) 2.269(3) 2.001(6) average

bond length (Å)

complex 5

complex 6

complex 7

complexes 5−7

complex 8

Th/U−Cl Th/U−O(CO) Th/U−O(H2O)

2.758(1) 2.472(3) 2.42(2)

2.759(1) 2.461(4) 2.431(4)

2.732(5) 2.451(14) 2.42(2)

2.749(5) 2.461(14) 2.424(4)

2.692(2) 2.424(4) 2.379(4)

Figure 1. Structure of complex 1: stick view (a), ball space-fill view (b), and ball (Th)-stick view (c) showing a hexagonal nanowheel. Color code: Th in light blue, C in gray, N in blue, and O in red. Hydrogen atoms are omitted for clarity.

has not been observed before for Q[5] complexes with Ln3+ ions.5a The introduction of K+ ions in the reaction mixture of thorium nitrate and Q[5] in a HCl solution leads to the formation of a heterometallic (Th−K) discrete complex 3 (Figure 3). Both Th4+ and K+ ions each occupy one side of the two Q[5] portals, forming a Th-Q[5]-K capsule with a

atoms from Q[5] lead the discrete structure into a hydrogen bonded 1D polymer (Figure S2, Table S1, Supporting Information). The discrete molecules are packed in layers together with Th4+ nitrate species in the crystal lattice (Figure S2, Supporting Information). A formate anion was included inside the Q[5] monodentately bonding to the Th4+ ion, which E


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Inorganic Chemistry

with two water molecules [2.844(10)−2.99(2) Å for K− O(H2O) bonding] and a bridging nitrate [3.012(14) Å for the K−O(NO3) bond] from a [Th(NO3)5(H2O)2]− anion. A NdQ[5]-K5s heterometallic bicapped complex with a nitrato ligand included in Q[5] bridging Nd3+ and K+ ions internally was previously reported. However, complex 3 has a totally different topology, with a Cl− anion included in Q[5] bonding to the Th4+ ion and a [Th(NO3)5(H2O)2]− anion coordinated to the K+ ion. The hydrogen bonding between coordinated water molecules and nitrate units leads to the formation of double heterometallic capsules (Figure 3b; Table S1, Supporting Information). The discrete capsules are closely packed in the crystal lattice (Figure S3, Supporting Information). The addition of Cs+ instead of K+ ions in a 6 M HCl solution containing Q[5] and thorium nitrate leads to the formation of a heterometallic (Th−Cs) 1D polymer 4 (Figure 4). Similar to complex 3, both Th4+ and Cs+ ions each occupy one side of the two Q[5] portals forming Th-Q[5]-Cs monomers (Figure 4) which are linked together by sharing two water molecules and one carbonyl oxygen atom between Th4+ and Cs+ ions from the nearby monomers, forming a 1D polymer (Figure 4b). The Th4+ ion is cap-coordinated to the five carbonyl O atoms [2.460(7)−2.524(7) Å for Th−O(CO) bonds] on one side, with three coordinated water molecules [2.424(7)−2.504(7) Å for Th−O(H2O) bonds] externally and an included Cl− [2.759(3) Å for Th−Cl bond] internally, making a 9-fold coordination geometry for the Th4+ center. The Cs+ ion, in an 11-fold coordination geometry, is capcoordinated by the opposite five carbonyl O atoms [2.915(7)− 3.361(8) Å for Cs−O(CO) bonds] with three coordinated water molecules [3.225(8)−3.434(10) Å for Cs−O(H2O) bonds], a monodentate nitrate [3.189(12) Å for Cs− O(NO3)], a bridging nitrate [3.149(9) Å for Cs−O(NO3) bond] from a [Th(NO3)5(H2O)2]− anion, and a carbonyl O atom (O9) from a nearby Q[5]. The bicapped monomers with coordinated [Th(NO3)5(H2O)2]− anions are connected through sharing two water molecules (O4W and O5W) and one carbonyl O (O9) between Th4+ and Cs+ ions with Th−Cs distance of 4.602(9) Å. The hydrogen bonds between coordinated water molecules and monodentate nitrate units lead the 1D polymers into 2D layers (Figure 4c; Table S1, Supporting Information) which are closely packed in the crystal lattice (Figure S4, Supporting Information). With transition metal chlorides as structure inducers, three 1D polymers (Th-Q[5]-Cd (complex 5), Th-Q[5]-Ru (complex 6), and Th-Q[5]-Ir (complex 7) (Figure 5)) have been isolated from 6 M HCl solutions. The 1D polymers in complexes 5−7 are similar, with the Th4+ ion cap-coordinated by five carbonyl O atoms and a Cl− anion inclusion on one side of a Q[5] molecule, two carbonyl O atoms on the other side from a nearby Q[5] molecule, and a coordinated water molecule with hydrogen bonding to two carbonyl O atoms (Figure S5), making a 9-fold coordination geometry for the Th4+ center. The coordinated water molecules inside Q[5] are hydrogen bonded to the two carbonyl O atoms (Figure S5, Supporting Information). The transition metal chlorides act as anions for charge compensation as well as structure inducers via cation−anion interactions, forming various anion patterns around the 1D polymers: undulating layers for complex 5 (Figure 5d; Figure S6a, Supporting Information), hexagonal honeycomb for complex 6 (Figure 5e; Figure S6b, Supporting

Figure 2. Structure of complex 2: The molecule contains a Th-Q[5]HCOO unit together with thorium nitrate hydrate species and nitrate anions (lattice water molecules and hydrogen atoms are omitted for clarity). Color code: Th in light blue sphere, C in gray, N in blue, and O in red sticks.

Figure 3. Structure of complex 3: a heterometallic (Th−K) Q[5] capsule with a [Th(NO3)5(H2O)2]− anion monodentate coordinated to the K+ ion (a) and two heterometallic capsules are linked together via hydrogen bonds between coordinated water and nitrate (b). Color code: Th in light blue, K in purple, Cl in green spheres, C in gray, N in blue, and O in red sticks.

[Th(NO3)5(H2O)2]− anion coordinated to the K+ ion via a bridging nitrate anion. The Th4+ ion is cap-coordinated to the five carbonyl O atoms [2.465(5)−2.511(4) Å for Th−O(CO) bonds], together with two water molecules [2.473(5) to 2.506(5) Å for Th−O(H2O) bonds], a bidentate nitrate [2.583(5)−2.606(5) Å for Th−O(NO3) bonds] externally, and a Cl− internally coordinated inside the Q[5] [2.782(2) Å for Th−Cl bond], making a 10-fold coordination geometry for the Th4+ center. The K+ ion, in an 8-fold coordination geometry, is cap-coordinated by the opposite five carbonyl O atoms [2.731(5)−2.807(5) Å for K−O(CO) bonds] together F


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Inorganic Chemistry

Figure 4. Structure of complex 4: a monomeric unit (a), the 1D polymer formation (b) (nitrate anions, lattice water molecules and hydrogen atoms are omitted for clarity), and a 2D layer formed by hydrogen bonds (blue dotted lines) between coordinated water and monodentate nitrate units (c). Color code: Th in light blue, Cs in purple, Cl in green and bridging O in orange spheres, C in gray, N in blue, and O in red sticks.

Figure 5. Structures of complexes 5−7: Th coordination environments and crystal packing views along the 1D polymers in complex 5 (a and d), complex 6 (b and e), and complex 7 (c and f).

double caps, Ln-Q[5]-K (Ln = Ce, Nd, Sm, Gd,);5r,s (5) heterometallic tetranuclear, two Pr-Q[5] units bridged by two Ca2+ ions;5s (6) 1D polymers, (Ln-Q[5])n (Ln = Yb,5r Ce,5l and La5c) with Q[5] molecules linked by Ln3+ ions in two carbonyl O atom bonding mode from both sides. However, some new structural features were identified in the current study for tetravalent actinide (Th4+/U4+) complexes with Q[5], e.g. a hexagonal nanowheel complex (1), a heteroleptic complex (2), a heterometallic complex (3), and two types of 1D polymers (4 and 5−8). Complex 1 has a unique hexagonal nanowheel structure. It is reasonable to assume that [Th(Q[5])(OH)]3+ species with cap coordination formed initially in solution are further self-assembled via monodentate coordination to the nearby species to form such a complex structure. In the literature, Th4+ ions coordinated with water molecules and bridged with hydroxyl or oxo- groups are quite common. However, oxo- or hydroxyl terminal coordination to Th4+ ion is rather rare with reported Th−OH distance of 2.10(3) Å and ThO distance of 1.928(9) Å.17 The average Th−O(OH) distance in complex 1 [2.124(4) Å] is consistent

Information), and polygonal for complex 7 (Figure 5f; Figure S6c, Supporting Information). In addition, the reduction of uranyl nitrate in situ with the presence of zinc metal in a HCl solution containing Q[5] leads to the formation of a 1D polymer U-Q[5]-Zn (complex 8) (Figure 6). Similar to the Th4+ ion coordination environments in complexes 5−7, the U4+ ion in complex 8 has a 9-fold coordination environment: a Q[5] cap coordination with a Cl− inclusion on one side and a water molecule and a bidentate Q[5] on the other side (Figure 6b). The coordinated water molecules inside the 1D polymer are hydrogen bonded to the carbonyl O atoms (Figure 6b). The hydrated zinc chloride anion species arranged in hexagonal honeycomb around the 1D polymers (Figure 6c; Figure S6d, Supporting Information). 3.3. Structure Discussion. Several types of Q[5] complexes with Ln3+ ions were previously identified, e.g. (1) homodinuclear with double caps, La-Q[5]-La;5n (2) homodinuclear with one cap and one side bonded by two carbonyl O atoms, Ln-Q[5]-Ln (Ln = La, Pr, Gd, and Nd);5o−q (3) homotrinuclear, Ln-Q[5]-Ln-Q[5]-Ln;5m (4) heterometallic G


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Inorganic Chemistry

Both CdCl2 and ZnCl2 were previously used as effective structure inducers for Q[n] complexes with Ln3+ ions.5 They were found to be also effective structure inducers for Th4+/U4+ ions in this work. In addition, RuCl3 and IrCl3 have been attempted and RuCl3 has been demonstrated to be a good structure inducer for Q[5] complexes with Th4+ ions. As Ru3+ ion can be oxidized to Ru4+ ion under the reaction conditions, a variety of Ru-containing anion species can assist the crystallization of the targeted 1D polymer in HCl solutions. 3.4. Magnetic Property. To probe the characters of magnetic interactions between the U4+ (5f 2) metal centers in complex 8, we collected variable temperature DC magnetic susceptibility data. The results (Figure 7) indicate that above

Figure 6. Structure of complex 8: Uranium coordination environment (a), hydrogen bonding (blue dotted lines) inside the 1D polymer (b), and crystal packing view along the crystallographic b-axis (c). Color code: U in yellow, Zn in gray and Cl in green spheres, C in gray, N in blue, and O in red sticks.

with the reported value for terminal hydroxyl coordination. Complex 2 has a 1:1 (Th:Q[5]) structure with Th4+ ion capcoordinated and a formate anion included in Q[5], representing a new heteroleptic mononuclear structure type. Complex 3 has a double capped heterometallic Th-Q[5]-K capsule with a [Th(NO3)5(H2O)2]− anion coordinated to the K+ ion, leading to a heterometallic complex. Complex 4 has a 1D polymeric structure built up with double capped heterometallic Th-Q[5]-Cs capsules linked together by two carbonyl O atoms bridging and sharing water molecules with an additional [Th(NO3)5(H2O)2]− anion coordinated to the Cs+ ion. The presence of additional [Th(NO3)5(H2O)2]− anions in either crystal lattice or bonded to the alkali metal ions in the Th-Q[5] system are the main structural features observed in complexes 2−4. Complexes 5−8 have the similar 1D polymeric structures, with cap coordination on one side and two coordinated carbonyl O atoms from the opposite direction. Such a mode of polymer connectivity for Th4+ and U4+ ions is unique due to their larger cation sizes and has not been observed for their Ln3+ counterparts. This is consistent with the early observation in which cap coordination of Q[5] was mainly found for early Ln3+ ions with relatively larger ionic radii.5a It is of interest to compare them and explore the subtle metal coordination differences. In fact, the 1D polymers in complexes 5−8 have several similarities: all (1) crystallize in monoclinic space group (Table 1) and (2) possess same 1D polymer connectivity. However, they also show some differences: (1) different anions and anion arrangements (Figure S5), leading to (2) slightly different cell parameters, and (3) relatively shorter U−O [2.424(4) Å for O(CO) and 2.379(4) Å for O(H2O)] and U−Cl [2.692(2) Å] bond lengths in complex 8 compared to the average Th−O [2.461(14) Å for O(CO) and 2.424(4) Å for O(H2O)] and Th−Cl [2.749(5) Å] bond lengths in complexes 5−7 (Table 3), reflecting the actinide contraction for the tetravalent ions in the early actinide series.

Figure 7. DC magnetic susceptibility (χ) (black line), inverse of χ corrected for diamagnetism (blue), Curie−Weiss fit (red), and χT product (inset) as a function of temperature for complex 8.

∼200 K the material behaves as a paramagnet with the data obeying the Curie−Weiss law. The linear fit in the range 200− 300 K yields the Weiss temperature very close to zero, 2.8(7) K, and the effective magnetic moment of 2.0(1) μB, a value falling within the range reported for other U4+ complexes.18 On further cooling, the material demonstrates antiferromagnetic correlations, as evidenced by decreasing μT product value (inset in Figure 7), however, without developing long-range magnetic order down to the lowest measurement temperature of 2 K. 3.5. Further Characterizations. The eight complexes were subjected to further structural and spectroscopic investigations. SEM-EDS examination of complexes 1−8 confirmed the crystal morphologies and the presence of key elements (Figure S7, Supporting Information). PXRD patterns (complexes 5−7) confirmed that the single crystals leading to the structure solutions in the crystallographic studies represent the bulk materials (Figure S8, Supporting Information). In general, the lack of diffraction data at 2θ > 30° is consistent with the extensive disorders of solvent molecules in the crystal lattice. 3.6. Vibrational Spectroscopy. Raman spectroscopy was successfully used to study the systematic trend of vibration modes in a series of Q[n]s.19a−d For Q[5], three major signature vibrations have been observed experimentally and confirmed with simulations: 452 cm−1 (s) [σ(N−C−N)], 826 cm−1 (vs) [δ(C−N−C) + ρ(CH2)], and 881 cm−1 (m) [β(C− N−C) + τ(N−C−C−N) + ν(C−C)]. Besides, Fourier transform infrared (FTIR) spectroscopy has also been used to investigate Q[5] and its complexes.19e The FTIR spectra for H


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Inorganic Chemistry

thorium nitrate with Q[5] in DI water leads to the formation of a unique hexagonal nanowheel via self-assembly of [Th(Q[5])(OH)]3+ species in solution. It has also been demonstrated that a variety of discrete complexes can be formed in acidic solutions, although 1D polymers are dominating in the presence of transition metal chlorides as the structure inducers because the coordination of Q[5] with tetravalent actinide ions occurs at the both sides of the portals with little chance of coordinating sideways. In fact, cap coordination by five carbonyl O atoms on one side of Q[5] is common for Th4+/U4+ ions due to their relatively larger cation sizes compared to their lanthanide counterparts. It is anticipated that other types of polymeric structures could also be possible by introducing second linker ligand or a proper second metal ion in the supramolecular assembly. The latter could lead to various heterometallic systems, evidenced by the formation of a polymeric complex 4 with the addition of Cs+ ions in the reaction system. In addition, the in situ reduction of (UO2)2+ to U4+ ions in HCl solution has been proven to be useful in the preparation of U4+ complexes and paves the way for further U4+ work with other Q[n] ligands.

complexes 6 and 7 (Raman not successful) shown in Figure S9, Supporting Information, are very similar to the FTIR spectrum of pure Q[5].19e However, the typical ν(CO) vibrations at 1733 cm−1 arising from the carbonyl stretch at the Q[5] portal splits into several peaks in the range of 1757 to 1647 cm−1. Such an extensive peak splitting for ν(CO) vibrations suggests that several different carbonyl environments are present due to the coordination of Q[5] to Th4+ ions, namely, cap-coordinated by five carbonyl O atoms on one side of a Q[5] molecule and two carbonyl O atoms on the other side, consistent with their crystal structures described above. Raman spectra for complexes 1−5 and 8 (Figure S10, Supporting Information) show typical Q[5] vibration modes of σ(N−C−N) and δ(C−N−C) in the regions 466−475 and 834−838 cm−1, respectively.19 It can be noted that both vibrational modes have slightly shifted to higher wavenumbers upon coordination to Th4+/U4+ ions, from 452 cm−1 to 466− 475 cm−1 for σ(N−C−N) and from 826 cm−1 to 834−838 cm−1 for the δ(C−N−C) band, respectively. This shift to higher wavenumbers indicates a formation of shorter (and stronger) bonds in the coordinated complexes in comparison to free Q[5] molecules, suggesting more inelastic Q[5] unit upon coordinating to Th4+/U4+ ions. In addition, νas(NO3) vibrations at around ∼1500 cm−1 have been observed for complexes 1−4, consistent with the presence of nitrate anions in these complexes. Detailed IR and Raman assignments for complexes 1−8 are available in Tables S2−4, Supporting Information. 3.7. Electronic Absorption Spectroscopy. The electronic structures of complexes 5−8 were further investigated through optical absorption spectroscopy in the UV−vis region. In principle, a Th4+ ion with 5f 0 configuration gives no f−f transitions. Thus, the electronic structures of compounds with Th4+ ions are mainly dominated by the ligands and their interactions with Th4+ ions. However, compounds with U4+ ions (5f 2 configuration) will show some weak f−f transition bands together with the contributions from the ligands. The UV−vis absorption spectra of complexes 5−8 are shown in Figure S11, Supporting Information. Ligand charge transfer (LC) of Q[5] contributes to the strong absorption bands in the far UV region, e.g. bands at 210 and 227 nm for complex 5, at 252 nm for complex 6, and at 230 nm for both complexes 7 and 8. As no d−d transition for Cd2+ ion (full shell 3d10 configuration) is possible, only very weak metal-to-ligand charge-transfer (MLCT) band for Th-Q[5] at 298 nm can be detected for complex 5. Similar reason for complex 8, no d−d transition for Zn2+ ion is possible. Thus, only weak MLCT at 285 nm and some weak f−f transition bands for U4+ (f 2) at 552, 638, 655, and 675 nm are present for complex 8.20 However, absorption bands corresponding to spin-allowed d− d transitions for Ru4+ ions (complex 6) and Ir4+ ions (complex 7) are obvious at 734 and 620 nm, respectively.21 In addition, MLCT bands are also found at around 359−380 and 460−475 nm for complexes 6−8.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.8b01347. Additional crystal structure figures, results on SEM-EDS, PXRD, Raman, FTIR, UV−vis, and hydrogen bonds (PDF) Accession Codes

CCDC 1478691−1478697 and 1843743 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, by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Yingjie Zhang: 0000-0001-6321-4696 Maxim Avdeev: 0000-0003-2366-5809 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS We would like to thank the Nuclear Materials Development and Characterization platform at ANSTO for facility access to synthesize and characterize the materials. The crystallographic data for complexes 1−7 were collected on the MX beamlines at the Australian Synchrotron, a part of ANSTO.

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4. CONCLUSIONS In summary, a series of eight Q[5] complexes with Th4+/U4+ ions exhibiting a variety of discrete and polymeric structures was synthesized by direct reactions and supramolecular assembly in either neutral or acidic aqueous solutions. This work accounts for the first systematic study on the Q[n] complexes with tetravalent actinide ions. The reaction of

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