Electronic Supporting Information For Structural and reactivity insights into covalently linked Cu(I) complex- Anderson polyoxometalates

Transcription

1 Electronic Supplementary Material (ESI) for Dalton Transactions. This journal is The Royal Society of Chemistry 2017 Electronic Supporting Information For Structural and reactivity insights into covalently linked Cu(I) complex- Anderson polyoxometalates 1. Instrumentation X-ray diffraction: Single-crystal X-ray diffraction studies were performed on an Agilent SuperNova CCD Single-crystal X-ray diffractometer or on a Bruker D8 Quest diffractometer equipped with a graphite monochromator using Mo Kα radiation (wavelength λ(mo Kα ) = Å). UV-Vis spectroscopy: UV-Vis spectroscopy was performed on a Varian Cary 50 spectrophotometer or JASCO V-670 spectrophotometer. All systems were used with standard cuvettes (d = 10.0 mm). Elemental analysis: CHN analysis was performed on a Elementar vario MICRO cube. Electrochemistry: DC cyclic voltammetry (CV) experiments were performed using a CH Instruments CHI 620E electrochemical workstation equipped with a standard three-electrode arrangement: working electrode: glassy carbon electrode (d = 1.6 mm), quasi reference electrode: Ag wire (in a glass frit containing electrolyte solution), counter electrode: Pt wire. All potentials are referenced relative to the ferrocene/ferrocenium external standard. CV experiments were performed in dry DMF using n Bu 4 NPF 6 as supporting electrolyte. All solutions were purged with argon for at least 3 min to remove O 2 and kept under a slight positive Ar pressure while performing the experiment. General remarks: All chemicals were purchased from Sigma Aldrich, ABCR or ACROS and were of reagent grade. The chemicals were used without further purification unless stated otherwise. ( n Bu 4 N) 3 [MMo 6 O 18 ((OCH 2 ) 3 CNCH(C 11 H 9 N 2 ) 2 ] (M = Mn 3+, Fe 3+ or Co 3+ ) was synthesized according to published procedure S1.

2 2. Synthetic section 2.1. Synthesis of ( n Bu 4 N)[MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu)) 2 ] x 3 CH 3 CN (1) First ( n Bu 4 N) 3 [MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 11 H 9 N 2 ) 2 ] (= {MnMo 6 -bpy 2 }, 10 mg, 4.46 µmol, 1 eq.) was dissolved in 2 ml acetonitrile (MeCN) giving a clear orange solution. Then, bis[(2- diphenylphosphino)phenyl] ether (= POP, 4.8 mg, 8.91 µmol, 2 eq.) and [Cu(NCCH 3 ) 4 ]BF 4 (2.8 mg, 8.9 µmol, 2 eq.) were dissolved in 2 ml dry acetonitrile at 50 C under inert atmosphere, leading to the in situ formation of the Cu(POP) ligand. The Cu(POP) solution was added to the {MnMo 6 -bpy 2 } solution whereby a colour intensification to orange was observed (see Fig. S1). The reaction mixture was stirred for 30 min at 50 C and centrifuged to remove precipitation. Yellow block crystals suitable for single crystal X-ray diffraction were obtained by slow evaporation of acetonitrile. Yield: 10.3 mg (3.52 µmol, 79 % based on Mo). Elemental analysis in wt.-% for C 126 H 129 N 10 MnMo 6 O 26 P 4 Cu 2 (calcd.): C (49.12), H 4.48 (4.22), N 4.49 (4.55) Synthesis of ( n Bu 4 N)[FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x DMF (2) First ( n Bu 4 N) 3 [FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 11 H 9 N 2 ) 2 ] (={FeMo 6 -bpy 2 }, 10 mg, 4.46 µmol, 1 eq.) was dissolved in 2 ml MeCN giving a clear pink solution. Then, bis[(2-diphenylphosphino)phenyl] ether (= POP, 4.8 mg, 8.91 µmol, 2 eq.) and [Cu(NCCH 3 ) 4 ]BF 4 (2.8 mg, 8.9 µmol, 2 eq.) were dissolved in 2 ml dry acetonitrile at 50 C under inert atmosphere, giving in situ formation of the Cu(POP) ligand. The Cu(POP) solution was added to the {FeMo 6 -bpy 2 } solution whereby a colour change from pink to yellow was observed (see Fig. S1). The reaction mixture was stirred for 30 min at 50 C and centrifuged to remove precipitation. Yellow block crystals suitable for single crystal X-ray diffraction were obtained by recrystallization from N,N-dimethylformamide (DMF) and diffusion of ethyl acetate into the solution. Yield: 4.9 mg (1.67 µmol, 38 % based on Mo). Elemental analysis in wt.-% for C 123 H 131 N 8 FeMo 6 O 27 P 4 Cu 2 (calcd.): C (48.66), H 4.31 (4.35), N 3.57 (3.69) Synthesis of ( n Bu 4 N)[CoMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] (3) First ( n Bu 4 N) 3 [CoMo 6 O 18 ((OCH 2 ) 3 CNCH(C 11 H 9 N 2 ) 2 ] (={CoMo 6 -bpy 2 }, 10 mg, 4.45 µmol, 1 eq.) was dissolved in 2 ml MeCN giving a clear teal solution. Then, bis[(2-diphenylphosphino)phenyl] ether (= POP, 4.8 mg, 8.91 µmol, 2 eq.) and [Cu(NCCH 3 ) 4 ]BF 4 (2.8 mg, 8.9 µmol, 2 eq.) were dissolved in 2 ml dry acetonitrile at 50 C under inert atmosphere, leading to the in situ formation of the Cu(POP) ligand. The Cu(POP) solution was added to the {CoMo 6 -bpy 2 } solution whereby a colour change from teal to green was observed (see Fig. S1). The reaction mixture was stirred for 30 min at 50 C and centrifuged to remove precipitation. Green block crystals suitable for single crystal X-ray diffraction were obtained

3 by recrystallization from N,N-dimethylformamide (DMF) and diffusion of ethyl acetate into the solution. Single crystal XRD study of 3 did not provide enough reflections to refine the structure satisfactorily. However, it was established without any doubt by unit cell measurement that the overall structure of compound 3 is identical to that of 1 and 2. Yield: 7.6 mg (2.60 µmol, 58 % based on Mo). Elemental analysis in wt.-% for C 120 H 124 N 7 FeMo 6 O 26 P 4 Cu 2 (calcd.): C (49.13), H 4.32 (4.26), N 3.39 (3.34). Figure S1. Photographs of the bipyridine-functionalized precursors {MnMo 6 -bpy 2 }, {FeMo 6 -bpy 2 } and {CoMo 6 - bpy 2 } in MeCN solution before addition of the POP ligand (top) and compounds 1, 2 and 3, displaying the colour change due to coordination of the POP ligand (bottom).

4 3. UV-Vis spectrometry 3.1. Absorption spectrum of ( n Bu 4 N)[MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x 3 CH 3 CN (1) Figure S2: UV-Vis absorption spectrum of 1 (2.5 x 10-5 M) in DMF showing very strong absorption in the near UV with λ max = 300 nm (ε 300nm = L mol -1 cm -1 ) attributed to π-π * intra-bipyridine transition and weaker absorption band in the visible with λ max = 388 nm (ε 388nm = 4302 L mol -1 cm -1 ) related to Cu(I) to bipyridyl MLCT Absorption spectrum of ( n Bu 4 N)[FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x DMF (2) Figure S3: UV-Vis absorption spectrum of 2 (2.5 x 10-5 M) in DMF showing very strong absorption in the near UV with λ max = 300 nm (ε 300nm = L mol -1 cm -1 ) attributed to π-π * intra-bipyridine transition and weaker absorption band in the visible with λ max = 380 nm (ε 380nm = 6224 L mol -1 cm -1 ) related to Cu(I) to bipyridyl MLCT.

5 3.3. Absorption spectrum of ( n Bu 4 N)[CoMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] (3) Figure S4: UV-Vis absorption spectrum of 3 (2.5 x 10-5 M) in DMF showing very strong absorption in the near UV attributed to π-π * intra-bipyridine transition, however this absorption peak cannot be resolved as it is believed to be superimposed by stronger POM-based O M LMCT bands and weaker absorption band in the visible with λ max = 388 nm (ε 388nm = 6675 L mol -1 cm -1 ) related to Cu(I) to bipyridyl MLCTs Photochemical stability of 1 Figure S5: Time-dependent UV-Vis absorption spectra of 1 (0.1 mm) in MeCN while irradiated (λ max = 470 nm, LED) over a period of 7 h, showing no spectral changes, thus highlighting the solution stability of 1 in MeCN.

6 4. Cyclic voltammertry 4.1. Cyclic voltammogram of ( n Bu 4 N)[MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x 3 CH 3 CN (1) Figure S6: Cyclic voltammogram of 1 (1 mm) in dry DMF with 0.1 M n Bu 4 NPF 6 as electrolyte Cyclic voltammogram of of ( n Bu 4 N)[FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x DMF (2) Figure S7: Cyclic voltammogram of 2 (1 mm) in dry DMF with 0.1 M n Bu 4 NPF 6 as electrolyte.

7 4.3. Cyclic voltammogram of of ( n Bu 4 N)[CoMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] (3) Figure S8: Cyclic voltammogram of 3 (1 mm) in dry DMF with 0.1 M n Bu 4 NPF 6 as electrolyte Cyclic voltammogram of [Cu(C 36 H 28 P 2 O)(C 12 H 10 N 2 O)]BF 4 = [Cu(POP)(mbpy)] + Figure S9: Cyclic voltammogram of [Cu(POP)(mbpy)] + (1 mm) in dry DMF with 0.1 M n Bu 4 NPF 6 as electrolyte.

8 5. Crystallographic section Suitable single crystals were mounted onto a microloop TM using Fomblin oil. X-ray diffraction intensity data were measured at 150 K on an Agilent SuperNova CCD or a Bruker D8 Quest diffractometer [λ(mo-k α ) = Å] equipped with a graphite monochromator. Structure solution and refinement was carried out using the SHELX-2013 package via OLEX2. Corrections for incident and diffracted beam absorption effects were applied using semi-empirical methods. Structures were solved by a combination of direct methods and difference Fourier syntheses and refined against F 2 by the full-matrix least-squares technique. The geometry and anisotropic refinement of the solvent, counter ion and ligand molecules was restrained using AFIX, SIMU and DELU. Crystallographic data can be obtained free of charge from CCDC Crystallographic data and structure refinement for ( n Bu 4 N)[MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x 3 CH 3 CN (1) Due to structural disorder on the tetrabutylammonium cation, no protons could be assigned. The metal oxo framework was refined without restraints. To account for diffuse solvent in the lattice, the SQUEEZE routine using PLATON was employed. The solvent accessible voids ( Å 3, e - ) contain approx. 15 acetonitrile molecules. Table 1 Crystallographic data for 1 ( n Bu 4 N)[MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x 3 CH 3 CN. Identification code CCDC Empirical formula C 126 H 129 Cu 2 MnMo 6 N 10 O 26 P 4 Formula weight Temperature/K (10) Crystal system triclinic Space group P-1 a/å (4) b/å (3) c/å (4) α/ (14) β/ (16) γ/ (18) Volume/Å (3) Z 2 ρ calc g/cm μ/mm F(000) Crystal size/mm Radiation CuKα (λ = ) 2Θ range for data collection/ 6.1 to Index ranges -22 h 21, -24 k 19, -24 l 31 Reflections collected 62000

9 Independent reflections [R int = , R sigma = ] Data/restraints/parameters 31719/478/1632 Goodness-of-fit on F Final R indexes [I>=2σ (I)] R 1 = , wr 2 = Final R indexes [all data] R 1 = , wr 2 = Largest diff. peak/hole / e Å /-0.84 Figure S10: ORTEP representation of the crystal structure of 1 ( n Bu 4 N)[MnMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x 3 CH 3 CN.

10 5.2. Crystallographic data and structure refinement for ( n Bu 4 N)[FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x DMF (2) C4, C123 and O27 were refined only isotropically due to structural disorder. The metal oxo framework was refined without restraints. To account for diffuse solvent in the lattice, the solvent mask routine implemented in OLEX2 was employed. The solvent accessible voids ( Å 3, 549 e - ) contain approx. 3 ethyl acetate and 10 DMF molecules. Table 2 Crystallographic data for 2 ( n Bu 4 N)[FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x DMF Identification code CCDC Empirical formula C 123 H 131 Cu 2 FeMo 6 N 8 O 27 P 4 Formula weight Temperature/K Crystal system triclinic Space group P-1 a/å (10) b/å (12) c/å (12) α/ (2) β/ (2) γ/ (3) Volume/Å (8) Z 2 ρ calc g/cm μ/mm F(000) Crystal size/mm Radiation MoKα (λ = ) 2Θ range for data collection/ to Index ranges -21 h 21, -26 k 26, -29 l 29 Reflections collected Independent reflections [R int = , R sigma = ] Data/restraints/parameters 33407/258/1512 Goodness-of-fit on F Final R indexes [I>=2σ (I)] R 1 = , wr 2 = Final R indexes [all data] R 1 = , wr 2 = Largest diff. peak/hole / e Å /-1.01

11 Figure S11: ORTEP representation of the crystal structure of 2 ( n Bu 4 N)[FeMo 6 O 18 ((OCH 2 ) 3 CNCH(C 47 H 37 N 2 P 2 OCu) 2 ] x DMF.

12 10. Literature references cited in SI S1 S. Schönweiz, S. A. Rommel, J. Kübel, M. Micheel, B. Dietzek, S. Rau and C. Streb, Chem. - A Eur. J., 2016, 22,