Square Planar Nickel(II) Complexes with Halogenated o‐Diiminobenzosemiquinonato Ligation: Synthesis, Characterization, and Redox Property. Issue 12 (4th November 2013)

• Record Type: Journal Article
• Authors: Zuo, Wansheng; Zhang, Long; Xie, Meihua; Deng, Liang
• Is Part Of: Chinese journal of chemistry. Volume 31:Issue 12(2013:Dec.)
• Page Start: 1473
• Page End: 1482
• Publication Date: 2013-11-04
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cjoc.201300664
• Languages: English
• ISSNs: 1001-604X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Seven square planar bis(<italic>o</italic>‐diiminobenzosemiquinonato)nickel(II) complexes, [Ni(<italic>o</italic>‐C<sub>6</sub>H<sub>4</sub>(NH)(NAr))<sub>2</sub>] (Ar=Mes, <bold>1</bold>; <italic>p</italic>‐F‐C<sub>6</sub>H<sub>4</sub>, <bold>2</bold>; <italic>p</italic>‐Cl‐C<sub>6</sub>H<sub>4</sub>, <bold>3</bold>), [Ni(<italic>o</italic>‐4, 5‐F<sub>2</sub>‐C<sub>6</sub>H<sub>2</sub>(NH)(NPh))<sub>2</sub>] (<bold>4</bold>), and [Ni(<italic>o</italic>‐4, 5‐Cl<sub>2</sub>‐C<sub>6</sub>H<sub>2</sub>(NH)(NAr))<sub>2</sub>] (Ar=Ph, <bold>5</bold>; 2, 6‐F<sub>2</sub>‐C<sub>6</sub>H<sub>3</sub>, <bold>6</bold>; 2, 6‐Cl<sub>2</sub>‐C<sub>6</sub>H<sub>3</sub>, <bold>7</bold>), have been synthesized and characterized by <sup>1</sup>H NMR, <sup>13</sup>C NMR, <sup>19</sup>F NMR, IR, UV‐Vis‐NIR, elemental analyses, HRMS, as well as single‐crystal X‐ray diffraction studies (<bold>1</bold> and <bold>7</bold>). The cyclic voltammograms of these complexes exhibit two reversible redox processes of [Ni<bold>L</bold><sub>2</sub>]<sup>0/1−</sup> and [Ni<bold>L</bold><sub>2</sub>]<sup>1−/2−</sup>, and one irreversible process of [Ni<bold>L</bold><sub>2</sub>]<sup>0/2+</sup>. Substituent effects on the redox properties of these complexes, in addition with those of the known complexes [Ni(<italic>o</italic>‐C<sub>6</sub>H<sub>4</sub>(NH)(NPh))<sub>2</sub>] (<bold>8</bold>) and [Ni(<italic>o</italic>‐3, 5‐Bu<sup><italic>t</italic></sup><sub>2</sub>‐C<sub>6</sub>H<sub>2</sub>(NH)<sub>2</sub>)<sub>2</sub>] (<bold>9</bold>), are identified by comparing the half‐wave potentials of the reduction waves, as <bold>1</bold>≈<bold>9</bold><<bold>8</bold>≈<bold>2</bold><<bold>3</bold><<bold>4</bold><<bold>5</bold><<bold>7</bold><<bold>6</bold>, reflecting the ease of reduction of [Ni<bold>L</bold><sub>2</sub>] parallels the electron‐donating and ‐withdrawing ability of the substituent group. Reduction of <bold>1</bold> with one or two equivalents of sodium metal in THF has led to the isolation of [Na(THF)<sub>3</sub>][<bold>1</bold>] and [Na(THF)<sub>3</sub>]<sub>2</sub>[<bold>1</bold>]. The structure data of these two complexes revealed by low‐temperature X‐ray crystallography suggest their corresponding electronic structures of [Ni<sup>II</sup>(<sup>1</sup><bold>L</bold><sup>·1−</sup>)(<sup>1</sup><bold>L</bold><sup>2−</sup>)]<sup>1−</sup> and [Ni<sup>II</sup>(<sup>1</sup><bold>L</bold><sup>2−</sup>)<sup>2</sup>]<sup>2−</sup>, which are in line with those of [<bold>9</bold>]<sup><italic>n</italic></sup> (<italic>n</italic>=1−, 2−) suggested by spectroelectrochemical study.</p> </abstract>