A cyclic bis[2]catenane metallacage

Catenated cages represent chemistry’s challenging synthetic targets because a three-dimensional assembly is necessary for their formation. Herein, a cyclic bis[2]catenane is constructed through the coordination-driven self-assembly of the interlocked bis-metallacage, by the 90° Pt(II) heteroligation of the endo-functionalized double-bridged tweezer bearing pyridyl moieties and the tetra-carboxylated linker. NMR spectrometry, X-ray crystallography and mass spectrometry confirm the formation of a cyclic bis[2]catenane with “∞”-shaped topology via a 14-component self-assembly. Particularly, reversibly responsive transformation between the bis[2]catenane and the bis-metallacage can be realized by guest exchange, concentration effect and solvent effect. This work represents a novel example of a cyclic cage-based [2]catenane oligomer.


Supplementary Methods
All reagents were commercially available and used as supplied without further purification. Deuterated solvents were purchased from Cambridge Isotope Laboratory (Andover, MA). Compound 1 1 , 4 2 ， p-Terphenyl-3,3'',5,5''-tetracarboxylic acid 3 ， 1-iodo-3,5-dimethoxy-benzene 4 was prepared according to the published procedures. 1 H NMR, 13 C NMR NMR spectra were recorded on a Varian Inova 400 MHz spectrometer and JEOL JNM-ECZ400SL NMR spectrometer. 31 P{ 1 H} NMR spectra were recorded on a Varian Unity 300 MHz spectrometer and JEOL JNM-ECZ400SL NMR spectrometer. DOSY spectra were recorded on a Varian Inova 500 MHz spectrometer and Bruker AVANCE III HD 500MHz spectrometer. COSY spectra were recorded on a Bruker AVANCE III HD 600MHz spectrometer. 1 H and 13 C NMR chemical shifts are reported relative to residual solvent signals, and 31 P{1H} NMR chemical shifts are referenced to an external unlocked sample of 85% H 3 PO 4 (δ = 0.0). Mass spectra were recorded on a Micromass Quattro II triple-quadrupole mass spectrometer using electrospray ionization with a MassLynx operating system. The single crystals data were collected on an Oxford Diffraction Xcalibur Atlas Gemini captra.
Supplementary Figure 1. The synthesis of 4-(3,5-dimethoxyphenyl)-pyridine. Synthesis of 4-(3,5-dimethoxyphenyl)-pyridine. 1-iodo-3,5-dimethoxy-benzene (2.64 g, 10 mmol), 4-Pyridineboronic acid (1.48 g, 12 mmol), CsF (3 g) and tetrakis(triphenylphosphine)palladium(0) (300 mg) were mixed in a 250 mL flask connected to a condenser. The flask was degassed under vacuum for 2 h, and then 100 mL of degassed 1,4-dioxane were added to the flask. The reaction mixture was heated to reflux under nitrogen atmosphere for 48 h. After removal of the organic solvent under vacuum, the residue was washed with water and extracted with CH 2 Cl 2 three times. Combined organic layers were dried over MgSO 4 and filtered. The solvent was removed and the crude product was purified by column chromatography on silica gel (ethyl acetate/hexane: 1/5) to give 1.25 g 4-(3,5-dimethoxyphenyl)-pyridine as a white solid. Yield: 58%. The 1 H NMR spectrum of 4-(3,5-dimethoxyphenyl)-pyridine is shown in Supplementary Figure 2      Crystal Structure Determination and refinements (For 3, NaOTf ⊂ 6 and 7). Single-crystal X-ray diffraction data was collected on a Nonius KappaCCD diffractometer equipped with Mo K-alpha radiation (λ = 0.71073 Å) and a BRUKER APEXII CCD. Throughout data collection, the crystal was cooled with an Oxford Cryosystem. The APEX3 software suite was used to manage data collection, reduction (SAINT V8.38A1), and absorption correction by the Multi-scan method (SADABS), structure determination via direct methods (SHLEXT) and model refinement (SHELXL). All non-hydrogen atoms were refined anisotropically though many atoms required anisotropic displacement parameter restraints. All hydrogen atoms were refined with isotropic displacement coefficients and their positions ideally constrained. Figure 28. Centroid-centroid distance and N···N distance (Å) of two benzene-pyridine arms from tweezer 3 in solid state (hydrogen atoms are omitted). Supplementary Figure 30. Multiple C-H· · · N hydrogen bonds between H atoms from aromatic rings and N atoms from naphthyridyl groups of 7 in solid state: C-H· · · N distances (Å).

Supplementary
The diffraction limit was found to be 1.5 Å and the data was trimmed accordingly Non-Solvent Resd Ueq(max)/Ueq(min) Range Disordered moieties remained unmodelled due to the low data/parameter ratio.
MainMol' Ueq as Compared to neighbours Disordered moieties remained unmodelled due to the low data/parameter ratio. Crystal Structure Determination and refinements (for 10). Single crystals of 10 were obtained by slow diffusion of n-hexane into an acetone solution of 10. Single-crystal X-ray diffraction data was collected on a Nonius KappaCCD diffractometer equipped with Mo K-alpha radiation (λ = 0.71073 Å) and a BRUKER APEXII CCD. Throughout data collection, the crystal was cooled with an Oxford Cryosystem. The crystal structure was solved and refined against all F 2 values using the SHELX and Olex 2 suite of programmes 5,6 . Crystals of bis [2]catenane presented a diffraction resolution of 1.5 Å. Only the platinium atoms were refined anisotropically. The rest of the atoms were refined isotropically due to a poor reflexions/parameters ratio. Hydrogen atoms were not placed in the calculated positions. The phenyl, napthyridyl and pyridyl groups were restrained to have idealized geometries using SHELX AFIX commands. The C-O distances in the carboxylate groups, P-C distances and C-C distances in PEt 3 groups were restrained using SHELX DFIX commands. The atomic displacement parameters (adp) of the ligands have been restrained using SHELX DELU, SIMU and REGU commands.

Supplementary
Single crystal of bis [2]catenane presents large voids filled with a lot of scattered electron density. Solvent mask protocol inside Olex 2 software was used to account for the void electron density corresponding to the disordered OTfanions and solvent molecules placed in the intermolecular space in the crystal structure.
A large number of A-alerts and B-alerts were found due to poor resolution (1.5 Å). Rigid Body was used to solve the structure of the bis [2]catenane. Different moieties of the bis [2]catenane were restrained to have idealized geometries and allowed to refine their position and orientation. Concentration of 6 (mM) in acetone-d 6 Percentage of

Solvents
Percentage of 9 Percentage of 10 Acetone-d 6 /CD 2 Cl 2 (v/v, 100/0) 5.1 94.9 Acetone-d 6  Where A is the chemical shift change of 6, A ∞ is the chemical shift change when the NaOTf is completely complexed, [H] 0 is the fixed initial concentration of the 6, and [G] 0 is the initial concentration of NaOTf. The association constants (K a ) was calculated by using the nonlinear curve-fitting method ( Supplementary Figures 59 and 60).