3‐Rhoda‐1, 2‐diazacyclopentanes: A Series of Novel Metallacycle Complexes Derived From CN Functionalization of Ethylene. Issue 41 (28th August 2014)

• Record Type: Journal Article
• Authors: Drover, Marcus W.; Beh, Daniel W.; Kennepohl, Pierre; Love, Jennifer A.
• Is Part Of: Chemistry. Volume 20:Issue 41(2014)
• Page Start: 13345
• Page End: 13355
• Publication Date: 2014-08-28
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201403682
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Rh‐containing metallacycles, [(TPA)Rh<sup>III</sup>(κ<sup>2</sup>‐(<italic>C</italic>, <italic>N</italic>)‐CH<sub>2</sub>CH<sub>2</sub>(NR)<sub>2</sub>‐]Cl; TPA=<italic>N</italic>, <italic>N</italic>, <italic>N, N</italic>‐tris(2‐pyridylmethyl)amine have been accessed through treatment of the Rh<sup>I</sup> ethylene complex, [(TPA)Rh(η<sup>2</sup><italic>‐</italic>CH<sub>2</sub>CH<sub>2</sub>)]Cl ([<bold>1</bold>]Cl) with substituted diazenes. We show this methodology to be tolerant of electron‐deficient azo compounds including azo diesters (RCO<sub>2</sub>NNCO<sub>2</sub>R; R=Et [<bold>3</bold>]Cl, R=<italic>i</italic>Pr [<bold>4</bold>]Cl, R=<italic>t</italic>Bu [<bold>5</bold>]Cl, and R=Bn [<bold>6</bold>]Cl) and a cyclic azo diamide: 4‐phenyl‐1, 2, 4‐triazole‐3, 5‐dione (PTAD), [<bold>7</bold>]Cl. The latter complex features two <italic>ortho</italic>‐fused ring systems and constitutes the first 3‐rhoda‐1, 2‐diazabicyclo[3.3.0]octane. Preliminary evidence suggests that these complexes result from N–N coordination followed by insertion of ethylene into a [Rh]N bond. In terms of reactivity, [<bold>3</bold>]Cl and [<bold>4</bold>]Cl successfully undergo ring‐opening using <italic>p</italic>‐toluenesulfonic acid, affording the Rh chlorides, [(TPA)Rh<sup>III</sup>(Cl)(κ<sup>1</sup>‐(<italic>C</italic>)‐CH<sub>2</sub>CH<sub>2</sub>(NCO<sub>2</sub>R)(NHCO<sub>2</sub>R)]OTs; [<bold>13</bold>]OTs and [<bold>14</bold>]OTs. Deprotection of [<bold>5</bold>]Cl using trifluoroacetic acid was also found to give an ethyl substituted, end‐on coordinated diazene [(TPA)Rh<sup>III</sup>(κ<sup>2</sup>‐(<italic>C, N</italic>)‐CH<sub>2</sub>CH<sub>2</sub>(NH)<sub>2</sub>‐]<sup>+</sup> [<bold>16</bold>]Cl, a hitherto unreported motif. Treatment of [<bold>16</bold>]Cl with acetyl chloride resulted in the bisacetylated adduct [(TPA)Rh<sup>III</sup>(κ<sup>2</sup>‐(<italic>C, N</italic>)‐CH<sub>2</sub>CH<sub>2</sub>(NAc)<sub>2</sub>‐]<sup>+</sup>, [<bold>17</bold>]Cl. Treatment of [<bold>1</bold>]Cl with AcNNAc did not give the RhN insertion product, but instead the N, O‐chelated complex [(TPA)Rh<sup>I</sup><bold>(</bold>κ<sup>2</sup>‐(<italic>O, N</italic>)‐CH<sub>3</sub>(CO)(NH)(NC(CH<sub>3</sub>)(OCHCH<sub>2</sub>))]Cl [<bold>23</bold>]Cl, presumably through insertion of ethylene into a [Rh]O bond.</p> </abstract>