2 research outputs found

    Molybdenum 1,4-Diazabuta-1,3-diene Tricarbonyl Solvento Complexes Revisited: From Solvatochromism to Attractive Ligand–Ligand Interaction

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    Various complexes of the types [Mo­(DAD)­(CO)<sub>3</sub>L] (L = CO, MeCN, MeOH, THF, DMSO, DMF, Me<sub>2</sub>CO, EtOAc, THT, Im<sup>H</sup>, Im<sup>1</sup>, <i>t</i>BuNC, <i>n</i>Bu<sub>3</sub>P), (ER<sub>4</sub>)­[Mo­(DAD)­(CO)<sub>3</sub>X] (ER<sub>4</sub> = NEt<sub>4</sub><sup>+</sup>; X<sup>–</sup> = Cl<sup>–</sup>, Br<sup>–</sup>, I<sup>–</sup>, NCS<sup>–</sup>, CN<sup>–</sup> and ER<sub>4</sub><sup>+</sup> = PPh<sub>4</sub><sup>+</sup>; X<sup>–</sup> = N<sub>3</sub><sup>–</sup>), and (ER<sub>4</sub>)­[{Mo­(DAD)­(CO)<sub>3</sub>}<sub>2</sub>(μ-X)] (ER<sub>4</sub><sup>+</sup> = NEt<sub>4</sub><sup>+</sup>; X<sup>–</sup> = CN<sup>–</sup>, OAc<sup>–</sup> and ER<sub>4</sub><sup>+</sup> = PPh<sub>4</sub><sup>+</sup>; X<sup>–</sup> = N<sub>3</sub><sup>–</sup>; DAD = <i>N</i>,<i>N</i>′-bis­(2,6-dimethylphenyl)­butane-2,3-diimine) were prepared by ligand exchange from cycloheptatriene molybdenum tricarbonyl. A total of 19 crystal structures were determined, including unprecedented structural characterization of molybdenum(0) coordination by dimethyl sulfoxide (DMSO), methanol, ethyl acetate (EtOAc), acetone, and <i>N</i>,<i>N</i>-dimethylformamide (DMF). Correlation of <sup>13</sup>C NMR shifts with the complex geometry suggests a direct ligand–ligand interaction between DAD and O-bonded coligands with CO and SO double bonds, such as EtOAc, Me<sub>2</sub>CO, DMF, and DMSO. Unexpectedly, the solvatochromic properties of these tricarbonyl complexes [Mo­(DAD)­(CO)<sub>3</sub>L] are unfavorable for the determination of Kamlet–Taft parameters of the corresponding solvent L. Contrastingly, the UV/vis absorption of [Mo­(DAD)­(CO)<sub>4</sub>] is strongly correlated with the Kamlet–Taft parameter π*, which is shown for 22 solvents, including seven room temperature ionic liquids

    Molybdenum 1,4-Diazabuta-1,3-diene Tricarbonyl Solvento Complexes Revisited: From Solvatochromism to Attractive Ligand–Ligand Interaction

    No full text
    Various complexes of the types [Mo­(DAD)­(CO)<sub>3</sub>L] (L = CO, MeCN, MeOH, THF, DMSO, DMF, Me<sub>2</sub>CO, EtOAc, THT, Im<sup>H</sup>, Im<sup>1</sup>, <i>t</i>BuNC, <i>n</i>Bu<sub>3</sub>P), (ER<sub>4</sub>)­[Mo­(DAD)­(CO)<sub>3</sub>X] (ER<sub>4</sub> = NEt<sub>4</sub><sup>+</sup>; X<sup>–</sup> = Cl<sup>–</sup>, Br<sup>–</sup>, I<sup>–</sup>, NCS<sup>–</sup>, CN<sup>–</sup> and ER<sub>4</sub><sup>+</sup> = PPh<sub>4</sub><sup>+</sup>; X<sup>–</sup> = N<sub>3</sub><sup>–</sup>), and (ER<sub>4</sub>)­[{Mo­(DAD)­(CO)<sub>3</sub>}<sub>2</sub>(μ-X)] (ER<sub>4</sub><sup>+</sup> = NEt<sub>4</sub><sup>+</sup>; X<sup>–</sup> = CN<sup>–</sup>, OAc<sup>–</sup> and ER<sub>4</sub><sup>+</sup> = PPh<sub>4</sub><sup>+</sup>; X<sup>–</sup> = N<sub>3</sub><sup>–</sup>; DAD = <i>N</i>,<i>N</i>′-bis­(2,6-dimethylphenyl)­butane-2,3-diimine) were prepared by ligand exchange from cycloheptatriene molybdenum tricarbonyl. A total of 19 crystal structures were determined, including unprecedented structural characterization of molybdenum(0) coordination by dimethyl sulfoxide (DMSO), methanol, ethyl acetate (EtOAc), acetone, and <i>N</i>,<i>N</i>-dimethylformamide (DMF). Correlation of <sup>13</sup>C NMR shifts with the complex geometry suggests a direct ligand–ligand interaction between DAD and O-bonded coligands with CO and SO double bonds, such as EtOAc, Me<sub>2</sub>CO, DMF, and DMSO. Unexpectedly, the solvatochromic properties of these tricarbonyl complexes [Mo­(DAD)­(CO)<sub>3</sub>L] are unfavorable for the determination of Kamlet–Taft parameters of the corresponding solvent L. Contrastingly, the UV/vis absorption of [Mo­(DAD)­(CO)<sub>4</sub>] is strongly correlated with the Kamlet–Taft parameter π*, which is shown for 22 solvents, including seven room temperature ionic liquids
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