A photochemical route to ferrocenyl-substituted ferrapyrrolinone complexes

Abstract

In the presence of iron pentacarbonyl, photochemical reaction between phenylisocyanate and ferrocenylacetylene results in ferrapyrrolinone complex [Fe2(CO)6(μ2-η3-FcC═C(H)C(O)NPh)] (1) and maleimide 3-ferrocenyl-1-phenyl-1H-pyrrole-2,5-dione (2). Under similar experimental conditions, ferrocenyl−/phenyl-substituted butadiyne primarily shows the activation of only one C☰C bond and results in ferrapyrrolinone complexes [Fe2(CO)6(μ2-η3-FcC═C(C☰CR)C(O)NPh)] (3, R = Fc; 3a, R = Ph), maleimides 3-ferrocenyl-1-phenyl-4-(ferrocenylethynyl)-1H–pyrrole-2,5-dione (5) and 3-ferrocenyl-1-phenyl-4-(phenylethynyl)-1H–pyrrole-2,5-dione (5a) and [Fe2(CO)6(μ2-η3-FcC═C(R)C(O)NPh)] (4; R = 3-ferrocenyl-1-phenyl-1H-pyrrole-2,5-dione). Compound 4 consists of ferrapyrrolinone and a maleimide unit, formed by the activation of both C☰C bonds of diferrocenylbutadiyne. Activation of both C☰C bonds in a substituted butadiyne is a rare observation. Formation of the ferrapyrrolinone compounds is an advance over the earlier reported methods which generally use internal alkynes and involve prior synthesis of other clusters. Copyright © 2017 John Wiley & Sons, Ltd.