Improved Syntheses of 1, 2‐Disubstituted Ferrocenes. Issue 2 (23rd September 2016)

• Record Type: Journal Article
• Authors: Werner, Georg; Butenschön, Holger
• Other Names: Štěpnička Petr guestEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 2(2017)
• Page Start: 378
• Page End: 387
• Publication Date: 2016-09-23
• Subjects: Ferrocene -- Sandwich complexes -- Iron -- Lithiation -- Halogenation; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201600766
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : 1, 2‐Disubstituted ferrocenes, in particular 1, 2‐dihaloferrocenes, are important starting materials. Herein, we describe significantly improved high‐yielding syntheses of 1, 2‐disubstituted ferrocenes such as 1, 2‐dibromo‐ and 1, 2‐diiodoferrocene as well as 1‐bromo‐2‐iodoferrocene, and 1‐bromo‐2‐fluoroferrocene. DFT calculations show that 1, 2‐dihaloferrocenes do not differ much in their highest occupied molecular orbital (HOMO) energies; however, their lowest unoccupied molecular orbital (LUMO) energies – and thus the HOMO/LUMO gaps – correlate with the sum of the halogen electronegativities. In addition, a synthesis of the rather sensitive 2‐aminoferrocenecarboxylic acid, the ferrocene analogue of anthranilic acid, is presented, which starts from ferrocene‐1, 2‐dicarboxylic acid. However, 2‐aminoferrocenecarboxylic acid rapidly decomposed and thus could not be properly characterized. Ferrocene‐1, 2‐dicarboxylic anhydride serves as the starting material for preliminary photochemical decarbonylation/decarboxylation experiments resulting in 1, 2‐dideuterioferrocene when carried out in [D8 ]toluene. Abstract : New or improved syntheses of useful 1, 2‐disubstituted ferrocenes are presented. These include 1, 2‐homo‐ and 1, 2‐heterodihaloferrocenes as well as ferrocene‐1, 2‐dicarboxylic anhydride, which is a potential precursor for 1, 2‐dehydroferrocene and 2‐aminoferrocenecarboxylic acid.