Controllable access to P-functional [3]ferrocenophane and [4]ferrocenophane frameworksElectronic supplementary information (ESI) available: Representation of NMR spectra of 2a,c, 3a, 4b,c, 5b,c, 6c, crystallographic data, electrochemical measurements, computed energies and atomic coordinates. Data of single crystal X-ray analyses and cif-files: CCDC 1587521 (5b), 1587522 (5c), 1587523 (3a), 1587524 (6c), 1587525 (4c), 1587526 (2c) and 1587527 (4b). For ESI and crystallographic data in CIF or oth

• Main Authors: Weller, Stefan, Schlindwein, Simon H, Feil, Christoph M, Kelemen, Zsolt, Buzsáki, Dániel, Nyulászi, László, Isenberg, Stefan, Pietschnig, Rudolf, Nieger, Martin, Gudat, Dietrich
• Format: Journal Article
• Published: 07.05.2019
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c9dt00892f

Condensation of secondary 1,1′-diaminoferrocenes with phosphorus trihalides (PCl 3 or PBr 3 ) yielded either P-halo-1,3-diaza-2-phospha[3]ferrocenophanes or 1,1′-diaminoferrocenediyl-bis(dichlorophosphines), respectively. The latter provide controlled access to both [3]- and [4]ferrocene frameworks. Thus, reductive coupling with magnesium gave diaza-diphospha[4]ferrocenophane-annelated tetraphosphetanes, while a reaction with LiNMe 2 produced a P-chloro-diazaphospha[3]ferrocenophane. Condensation of diaminoferrocenes and aminodichlorophosphines were mostly unselective, but afforded in one case a 3-amino[3]ferrocenophane. All reaction products were characterised by spectroscopic and single-crystal XRD studies. DFT studies indicate that the product selectivity in the reactions studied depends on a combination of kinetic and thermodynamic effects, which correlate subtly with the steric bulk of the N -substituents. Cyclic voltammetry measurements revealed that the ferrocenophanes can undergo multiple oxidation events, the first of which may according to DFT studies be located in both the ferrocene and aminophosphine units. The quantum chemical studies provided also insight into stereochemical aspects like ring strain in the ferrocenophane units. Condensation of 1,1′-diaminoferrocenes with PCl 3 gives access to P-halo-diazaphospha-[3]ferrocenophanes and [4]ferrocenophane-annelated tetraphosphetanes, which can undergo multiple oxidation in both ferrocene and aminophosphine units.