Jörg Harloff

Tetracyanido(difluorido)phosphates M+[PF2(CN)4]−†

The systematic study of the reaction of M[PF6 ] salts and Me3 SiCN led to a synthetic method for the synthesis and isolation of a series of salts containing the unprecedented [PF2 (CN)4 ](-) ion in good yields. The reaction temperature, pressure, and stoichiometry were optimized. The crystal structures of M[PF2 (CN)4 ] (M=[nBu4 N](+) , Ag(+) , K(+) , Li(+) , H5 O2 (+) ) were determined. X-ray crystallography showed the exclusive formation of the cis isomer in accord with (31) P and (19) F solution NMR spectroscopy data. Starting with the K[PF2 (CN)4 ] the room temperature ionic liquid EMIm[PF2 (CN)4 ] was prepared exhibiting a rather low viscosity.

Molecular E(CN)3 (E=Sb, Bi) Species Synthesized from Ionic Liquids as Solvates.

The heavy pnictogen tricyanides, E(CN)3 (E=Sb, Bi), were synthesized from EF3 and Me3 SiCN in ionic liquids, for example, 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIm][OTf]), which prevents the oligomerization of the molecular E(CN)3 species by formation of [BMIm][E(CN)3 (OTf)] salts in solution. Recrystallization of [BMIm][E(CN)3 (OTf)] from THF led to the isolation and full characterization of the molecular species E(CN)3 ⋅2 THF.

Lewis Acid Catalyzed Synthesis of Cyanidophosphates.

Salts containing new cyanido(fluorido)phosphate anions of the general formula [PF6-n(CN)n](-) (n=1-4) were synthesized by a very mild Lewis-acid-catalyzed synthetic protocol and fully characterized. All [PF6-n(CN)n](-) (n=1-4) salts could be isolated on a preparative scale. It was also possible to detect the [PF(CN)5](-) but not the [P(CN)6](-) anion. The best results with respect to purity, yield, and low cost were obtained when the F(-)/CN(-) substitution reactions were carried out in ionic liquids.

Arsenic‐Mediated C−C Coupling of Cyanides Leading to Cyanido Arsazolide [AsC4N4]−

The chemistry of arsenic cyanides has been investigated and is found to be completely different to the chemistry of the heavier analogs antimony and bismuth as well as phosphorus. The reaction of As(CN)3 with cyanide salts resulted in the formation of an unknown cyanido arsazolide heterocycle, which represents a structure isomer of the desired [As(CN)4 ]- . The structure, bonding, and formation of this unusual heterocycle is discussed featuring an arsenic mediated C-C coupling of cyanides. [AsC4 N4 ]- salts with different counterions such as [PPh4 ]+ , [PPN]+ =[Ph3 P-N-PPh3 ]+ , Ag+ , and [BMIm]+ are reported with [BMIm][AsC4 N4 ] being a low-temperature ionic liquid (Tm =-62 °C).