diazadiphosphacyclotetradecine ((1S,4S,9R,10R)-1b) were prepared by condensing the new, enantiomerically pure synthon 2,2′-((1S ,1′S )-ethane-1,2-diylbis(phenylphosphinediyl))dibenzaldehyde ((S,S)-8), prepared in six steps from (2R,4S,5R)-3,4-dimethyl-2,5-diphenyl-1,3,2-oxazaphospholidine-2-borane (3)), with (1S,2S)-cyclohexane-1,2-diamine and (1R,2R)-1,2diphenylethane-1,2-diamine under high-dilution conditions. The opposite enantiomers of the diamines gave oligomeric products. The stereospecificity of the macrocyclization reaction is explained by conformational analysis based on the X-ray structures of (1S,4S,9S,10S)-1a and (1S,4S,9R,10R)-1b. The corresponding diamino macrocycles (1S,4S,9S,10S)-2a and (1S,4S,9R,10R)-2b were prepared by reduction of the imine moiety of (1S,4S,9S,10S)-1a and (1S,4S,9R,10R)-1b, respectively. Macrocycles (1S,4S,9S,10S)-1a, (1S,4S,9R,10R)-1b, and (1S,4S,9S,10S)-2a react with [Fe(OH 2 ) 6 ](BF 4 ) 2 in acetonitrile to give the corresponding stable, diamagnetic bis(acetonitrile) complexes [Fe(MeCN) 2 ( 1)](BF 4 ) 2 (9a and 9b) and [Fe(MeCN) 2 (2a)]-(BF 4 ) 2 (10a). Complex 9a exists as a 3:1 mixture of trans and Λ-cis-β isomers, whereas 9b and 10a adopt the Λ-cis-β configuration exclusively. The bis(acetonitrile) complexes are versatile precursors and were used to prepare the bromocarbonyl analogues [FeBr(CO)(1)]BPh 4 (11a and 11b).

Starting from N-trifluoromethyl benzimidazole (1), a series of N-trifluoromethyl benzimidazolium salts 2a–f·HA have been prepared and fully characterized. These were engaged in the formation of [Ir­(CO)2(NHC)­Cl], [Rh­(COD)­(NHC)­Cl], [Se­(NHC)], and [Au­(NHC)­Cl] derivatives. IR analysis of [Ir­(CO)2(NHC)­Cl] complexes revealed that the trifluoromethyl substituent on nitrogen significantly decreases the σ-donating ability of the carbene carbon. On the other hand, the π-acceptor property of these novel ligands is enhanced. Examination of the 77Se NMR resonance of [Se­(NHC)] adducts and the redox potentials of [Rh­(NHC)­(COD)­Cl] complexes further supports this assumption. In addition, the efficiency of these new N-trifluoromethyl NHC ligands was investigated in π-acidic Au­(I)-catalyzed hydroalkoxylation of cyclohexene. The gold complexes bearing NHCs 2a and 2c–e compete with [Au­(PPh3)­Cl] in terms of catalytic activity.

The crystal structures of different perfluoroorganyl iodanes are described, including those of four new benziodoxole derivatives with RF = n‐C3F7, n‐C4F9, n‐C8F17, and C6F5. In all of the compounds, the iodine atom shows significant Lewis acidity, and the fourth coordination site is readily filled by secondary bonding interactions to produce square‐planar coordination. Although this geometry is a good model for benziodoxoles, benziodoxolone derivatives tend to aggregate further through additional weak I···O or I···aryl contacts. The different interactions lead to the formation of various assemblies with different dimensions in the solid state. The protonation of the reagents results in the formation of entirely different supramolecular structures, which are supported by hydrogen bonding. The structural features of the reagents in the solid state reflect well their behavior in solution, and the I–C(RF) bond is influenced by the coordination of Lewis basic solvents to the iodine atom and by hydrogen bonding with protic solvents. These solvent effects are more pronounced for reagents containing the trifluoromethyl fragment than for derivatives with longer RF chains.

SummaryThe synthesis of 5-nitro-1-(trifluoromethyl)-3H-1λ3,2-benziodaoxol-3-one (3), a hypervalent-iodine-based electrophilic trifluoromethylating reagent, is described. Whereas considerations based on cyclic voltammetry and X-ray structural properties would predict an inferior reactivity when compared to the non-nitrated derivative 2, 19F NMR kinetic studies showed that this new derivative is almost one order of magnitude more reactive. Furthermore, differential scanning calorimetry measurements indicated that, in addition, it is also safer to handle.

This mild TCICA/KF oxidative fluorination approach provides controllable access to aryl-IF2 and aryl-IF4 compounds, thus allowing detailed structural studies.