Synthesis, Structure, Magnetic Properties and Phase Diagram of a

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Synthesis, Structure, Magnetic Properties and Phase Diagram of a

    # Supplementary Material (ESI) for Chemical Communications # This journal is ? The Royal Society of Chemistry 2003

    Supporting Information

    for the manuscript

    From metal to ligand electroactivity in nickel(II) oxamato complexes


    aaaaaXavier Ottenwaelder, Rafael Ruiz-García, Geneviève Blondin, Rosa Carasco, Joan Cano,

    baaDoris Lexa, Yves Journaux and Ally Aukauloo*

a Laboratoire de Chimie Inorganique, UMR 8613, Université Paris-Sud, 91405 Orsay (France) b Laboratoire de Bioénergétique et Ingénierie des Protéines, 31 chemin Joseph Aiguier,

    13402 Marseille Cedex 20 (France).


Syntheses of ligands S2

    Syntheses of complexes S4

    Electrochemistry S4

     Fig S2: Cyclovoltammograms

    UV-Vis-NIR S6

     Fig S3: UV-Vis of the Ni(II) complexes 14.

    oxox Fig S4 and Table S2: UV-Vis-NIR of the oxidized complexes 14.

    References S7


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    Synthesis of ligands: All ligands were isolated as their diethyl esters, noted EtH-XL. The proligand 222123with X = H and compounds 4,5-dinitroveratrole and 4,5-diamino-1,2-dinitrobenzene have already been described.

    XXXXHNNH22,X = NO2X = NOH, Me2

    , Pd/CHClOEt2


    88?0 %OOEtEtOOOOEtEtOO

    (CHO)AcOHClOEt2nDMFNaBHCN70 %378 %OO


    H, Pd/C2




    XXĞXXĞ2 1) 4 OH2+2) Ni+2 PPh43) 2 PPhCl4

    OOOONHHNNN58?2 %Ni



X = Me, NO: To a solution of the corresponding 4,5-disubstitued o-phenylenediamine (10 mmol) in 2

    THF (100 mL) was added ethyl oxalyl chloride (2.7 mL, 24 mmol). The mixture was then refluxed for

    30 min, filtered to remove any insoluble material and evaporated to dryness. Addition of water to the

    resulting oil gave a solid that was filtered off, well washed with water and diethyl ether, and finally dried

    under vacuum. If necessary, this solid was then purified by flash-chromatography over silica with a

    dichloromethane methanol (9:1) eluant. X = Me (white solid, 2.96 g, 88%): CHNO (336.4): 1620261calcd. C, 57.14; H, 5.99; N, 8.33; found: C, 56.98; H, 5.87; N, 8.28. H NMR (CDCl): ; = 1.39 (t, 3

    6H, CH of ethyl), 2.22 (s, 6H, CH on the benzene ring), 4.37 (q, 4H, CH), 7.33 (s, 2H, aromatic), 33219.19 (s, 2H, NH). IR (KBr): = 3263 (NH), 1732, 1712 and 1672 cm (C=O). X = NO (light brown 2

    solid, 3.58 g, 90%): CHNO (398.3): calcd. C, 42.22; H, 3.54; N, 14.07; found: C, 41.78; H, 3.49; 1414410


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    1N, 13.70. H NMR (CDCl): ; = 1,42 (t, 6H, CH), 4.43 (q, 4H, CH), 8.42 (s, 2H, aromatic), 9.63 (s, 33212H, NH). IR (KBr): = 3293 (NH), 1753, 1737, 1712 and 1696 cm (C=O), 1527 (broad, NO). 2

    X = OMe:

    a) diamine. This synthesis has been carried out under inert atmosphere. A suspension of 4,5-

    2dinitroveratrole (5.1 g, 22.4 mmol) and 10% Pd / C (500 mg) in methanol (200 mL) was stirred overnight under a high presure atmosphere of dihydrogen (40 bar). The mixture was then filtered over celite and well washed with methanol until the filtrate was colorless. After removal of the solvent,

    1colorless crystals of 4,5-diaminoveratrole covered by a deep green oxidation product were collected. H

    NMR (degased [D]DMSO): ; = 3.57 (s, 6H, CH), 4.09 (s, 4H, NH), 6.25 (s, 2H). IR: 3417, 3352 632

    and 3222 (NH).

    b) Proligand. This solid material was then dissolved in DMF (100 mL) and excess ethyl oxalyl chloride (7 mL, 60 mmol) was added. The brown solution was stirred at 90?C for 15 min and diisopropylethylamine (11 mL, 63 mmol) was added. After further 15 min at 90?C, the solution was cooled and filtered under air. After removal of the solvent and addition of water, a light brown precipitate formed which was filtered off. This solid was then purified by flash-chromatography over silica eluted with a dichloromethane methanol (5:1) mixture. The light-yellow solution was collected

    and evaporated to dryness. The white, slightly orange solid was collected with pentane and dried under vacuum (6.4 g, 78%). CHNO (368.4): calcd. C, 52.17; H, 5.47; N, 7.61; found: C, 52.29; H, 16202815.49; N, 7.57 H NMR (CDCl): ; = 1.40 (t, 6H, CH), 3.85 (s, 6H, OCH), 4.39 (q, 4H, CH), 7.11 33321(s, 2H, aromatic H), 9.16 (s, 2H, NH) IR (KBr): = 3328 and 3266 (NH), 1748, 1731 and 1688 cm


    X = NH: A suspension of solid EtH-(NO)L (3.43 g, 8.6 mmol) and 10% Pd / C (350 mg) in 22222

    methanol (200 mL) was stirred overnight under a 40 bar atmosphere of dihydrogen. The mixture was then filtered over Celite and copiously washed with methanol. The solution was then evaporated to give a yellow solid that was collected with diethyl ether and conserved under vacuum (2.71 g, 93%).

    1CHNO (338.3): calcd. C, 49.70; H, 5.36; N, 16.56; found: C, 49.46; H, 5.39; N, 16.66 H NMR 1418466(DMSO-d): ; = 1.28 (t, 6H, CH), 4.26 (q, 4H, CH), ), 4.73 (s, 2H, NH), 6.65 (s, 2H, aromatic), 9.95 3221(s, 2H, NH) IR (KBr): = 3231, 3361 and 3434 (NH), 1690, 1724 and 1761 cm (C=O).

    4X = NMe: To a suspension of paraformaldehyde (1.33 g, 44 mmol) in glacial acetic acid (45 mL) 2

    under inert atmosphere was added solid EtH-(NH)L (1.50 g, 4.4 mmol). Then, solid sodium 2222

    cyanoborohydride (1.4 g, 22 mmol) was added portionwise to the stirred mixture. The suspension was degased and left for 15 h under stirring. The solution was then filtered and evaporated to dryness, resulting in a yellow oil to which were added successfully dichloromethane (50 mL) and water (50 mL). After several extractions, the combined yellow organic layers were washed three times with water and dried over anhydrous sodium sulfate. Evaporation to dryness yielded a yellow oil which was flash-chromatographied over silica eluted with dichloromethanemethanol (2-5% in MeOH). The desired

    product was precipitated with pentane from a solution in the minimum amount of dichloromethane. This yellow solid was then dried under vacuum (1.22 g, 70%). CHNO (394.4): calcd. C, 54.81; H, 18264616.64; N, 14.20; found: C, 54.82; H, 6.47; N, 14.24. H NMR (CDCl): ; = 1.40 (t, 6H, CH of ethyl), 33


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2.75 (s, 12H, N(CH)), 4.39 (q, 4H, CH), 6.99 (s, 2H, aromatic), 9.15 (s, 2H, NH). IR (KBr): = 32213254 (NH), 1737 and 1690 cm (C=O).

    4Synthesis of nickel (II) complexes: The nickel (II) complexes of XL ligands have been obtained by 2

    2+reaction of the tetraethylester EtH-XL with Ni in basic aqueous media, and isolated as their 222

    tetraphenylphosphonium salts by extraction in dichloromethane. For X = OMe and NMe, the synthesis 2

    has been realized under inert atmosphere. To a suspension of EtH-XL (2.0 mmol) in water (20 mL) 222

    was added an solid sodium hydroxyde (340 mg, 8.5 mmol). After stirring at room temperature until

    .complete dissolution (5 min), an aqueous solution (20 mL) of Ni(NO)6HO (582 mg, 2.0 mmol) was 322

    slowly added dropwise. The orange complex was then extracted several times with dichloromethane and tetraphenylphosphonium chloride (1.5 g, 4.0 mmol) added in several portions. The combined organic layers were washed 5 times with water, filtered through a paper and evaporated to dryness. The orange oil was dissolved in a minimum amount of acetonitrile and precipitation was carried out with acetone. The orange powder was then collected, well washed with acetone and dried under vacuum. Yields and physical characterisations are reported in Table S1.

Table S1. Physico-chemical characterisations of the complexes 14.

    [b]1[c][d] Elemental analysis found (calcd.) IR HNMR UVVis

    [a]111 n MW Yield %C %H %N %P (C=O) / cm ; / ppm / nm ( /

    0 985.6 70% 70.13 (70.68) 4.44 (4.50) 2.91 (2.84) 6.10 (6.28) 1628, 1651, 1667 7.99 356 (8900) 1

    0 1013.7 66% 70.17 (71.09) 4.76 (4.77) 2.88 (2.76) 6.04 (6.11) 1620, 1648, 1665 7.82, 1.97 356 (8970) 2

    0 1045.7 58% 68.13 (68.92) 4.79 (4.63) 2.87 (2.68) 5.86 (5.92) 1619, 1638, 1661 7.77, 3.68 362 (9790 3

    2 1107.8 66% 67.74 (67.22) 5.28 (5.28) 4.86 (5.06) 5.21 (5.59) 1619, 1640, 1661 7.34, 2.61 365 (11510) 4

    [a] Number of crystallisation water molecules. [b] in KBr. [c] Protons of the dianionic moiety only. [d] CHCl, 20?C. [e] 1 also presents 22

    11a broad band between 460 and 600 nm ( ? 6000 /

    General: All reagents were obtained from commercial sources and used as received. For electrochemical and oxidation reactions, dichloromethane was distilled over CaH under N prior to use. 22

    Elemental analyses were performed by the Microanalytical Service of ICSN (CNRS). NMR spectra were recorded on AC200 and AC250 spectrometers (Bruker). IR spectra were carried out on a Spectrum 1000 FT-IR spectrophotometer (Perkin Elmer). UV-Vis-NIR spectra have been realised on a Cary 5E (Varian, 200-1500 nm). EPR measurements were performed at 100 K on a ER 200 E (Bruker) and Elexys 500 (Bruker) at X-band.

    Electrochemistry: Electrochemical measurements were performed on a PAR 273A (EG&G) equipment. All experiences were carried out under an argon atmosphere. The supporting salt was NBuPF, 46

    recristallized twice from ethyl acetate / heptane, dried under vacuum and kept at 110?C. NBuClO has 44

    also been used without any noticeable differences in the voltammograms.

    For cyclovoltametric studies, the working electrode was a Pt disk, the counter electrode was a Pt

    2wire, and the reference was a AgClO (10 M in CHCN) || Ag electrode. After all measurements 43+ferrocene (Fc) was added as internal reference. The potential of Fc/Fc couple was taken to +460 mV vs


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    5SCE. The reversibility of the first oxidation process is evidenced by the dependence of peak currents with the square-root of the scan rate.

    For electrolysis, the preparating electrode was a Pt grid and the same reference electrode was used. The counter electrode was isolated from the solution with a fritted glass. As the electrooxidised solutions were not very stable, electrolyses were performed at 30?C. No significant deviations of the

    potentials were observed between +20?C and 30?C (+20 to +30 mV on cooling). For each complex,

    coulometric measurements confirmed the 1e nature of the oxidation, and cyclic voltammograms ran on

    the electrooxidised solutions showed a reversible reduction wave at the same potential measured on the

    initial solution. This confirms the presence of a complex deficient by 1e and that no chemical

    modification has accompanied the electron transfer reaction. The 1e nature of the process was also

    assessed by titration with a monoacetylferrocenium solution of know concentration. After electrolysis, EPR tubes were filled under argon and rapidly cooled in liquid nitrogen. UV-Vis-NIR spectra of the oxidized species were recorded at 30?C and are consistent with those, more precise,

    measured by direct spectroelectrolysis. The apparatus for spectroelectrolysis experiments is described

    6elsewhere. It consists of a 0.5 mm quartz UV-Vis-NIR cell surmonted by a glass compartment. The working electrode was a 3 cm 0.7 cm 0.3 mm Pt grid with a wire covered with teflon to avoid

    electrolysis elsewhere than in the quartz window. The reference and the counter electrodes are located on the top of the cell. The entire solution was under argon, and the cell was cooled to 30?C by a home-

    made cryostat. Clean isosbestic evolution is observed in all cases and the quantitative (>98%) recovery of the initial electronic spectra after reduction of the oxidised solutions indicates the reversible nature of the electron transfer within the experimental conditions (over 2 hours).

Fig. S2 Cyclovoltammograms of 4 to 1 (from left to right); 1 mM in CHCl, 0.1 M NBuPF, Pt, 20?C, 22461100 mV.s.

    NMeOMeMeHX =2

    5 A

    i / A


    E / V vs SCE


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    oxoxFig. S3 Electronic spectra of the initial (-------) and electrooxidised (——) solutions for 1/14/4; CHCl, 30?C, 0.1 M NBuPF. 2246

    12000)4 (NMe2

    100003 (OMe)


    60002 (Me)1 (H)Ğ1Ğ1 / M.cm4000




     / nm


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     oxoxFig. S4 Electronic spectra of the initial (-------) and electrooxidised (——) solutions for 1/14/4; CHCl, 30?C, 0.1 M NBuPF. 2246

    10000oxox1/1: X = H2/2: X = Me



    Ğ1Ğ14000 /




     / nm / nm


    oxox: X = OMe4/4: X = MeN3/3210000



    Ğ1Ğ1 / M.cm4000



     / nm / nm oxox[a]Table S2. Electronic spectra of complexes 1 to 4 for > 600 nm.

    11Complex / nm ( / max

    ox668 (sh) 735 (1980) 845 (sh) 969 br (6270) 3

    ox674 (sh) 757 (1540) 870 (sh) 1014 br (6710) 4

    ox688 (920) 765 (sh) 863 br (3920) 993 br (5820) 5

    ox 872 br (6120) ? 1000 (sh) 6

    [a] CHCl, 0.1 M NBuPF, 30?C. 2246


    1 H. O. Stumpf, Y. Pei, O. Kahn, J. Sletten and J. P. Renard J. Am. Chem. Soc. 1993, 115, 6738. 2 T. Collins, R. Powell, C. Slebodnick and E. Uffelman J. Am. Chem. Soc. 1991, 113, 8419. 3 G. Cheeseman J. Chem. Soc. 1962, 1170.

    4 G. Gribble and C. Nutaitis Synthesis 1987, 709.

    5 N. Connelly and W. Geiger Chem. Rev. 1996, 96, 877.


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6 C. Gueutin and D. Lexa Electroanalysis 1996, 8, 1029.


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