From Polyhalides to Polypseudohalides: Chemistry Based on Cyanogen Bromide

Abstract

Pseudohalogens are defined as molecular entities that resemble the halogens in their chemistry.W hile our understanding of polyhalogen chemistry has increased over the last years,r esearcho np olypseudohalogen compounds is lacking. The pseudohalogen BrCN possesses ah ighly pronounced s-hole at the bromine side of the molecule,i nducing strong halogen bonding.T his allows the synthesis and characterization of new polypseudohalogen anions,a ss hown by the single-crystal X-rayd iffraction of [PNP][Br(BrCN)] and [PNP][Br(BrCN) 3 ]. Both the nearly linear anion [Br-(BrCN)] À and the distorted pyramidal anion [Br(BrCN) 3 ] À were characterized by Raman spectroscopya nd quantumchemical calculations.The behavior of the polypseudohalogen compounds in solution and as room-temperature ionic liquids (RT-ILs) using the [NBu 4 ] + cation was studied by 13 Cand 15 N NMR spectroscopy. These types of ILs are capable of dissolving elemental gold and offer themselves as promising compounds in metal recycling.

Salts of HCN‐Cyanide Aggregates: [CN(HCN)2]− and [CN(HCN)3]−

“…The group of Fehlhammer isolated [M‐CN⋅⋅⋅H⋅⋅⋅NC‐M] − complexes (M=Cr(CO) 5 ) from the reaction of [Ph 4 As][Cr(CN)(CO) 5 ] and [Cr(CO) 5 CNH] . More recently, Riedel and co‐workers reported the isolation of pseudohalogen halides of the type [Br(BrCN)] − and [Br(BrCN) 3 ] − . As we had recently been studying the stabilization of HCN dimers by strong Lewis acids, we investigated the reaction of Lewis bases such as CN − and HCN to isolate salts containing HCN‐cyanide aggregates of the type [CN(HCN) n ] − ( n= 1, 2, 3 …).…”

Chalcogen Bonding of SO2 and s‐Block Metal Iodides Near Room Temperature: A Remarkable Structural Diversity

“…As the presented SO 2 ‐chemistry is mainly characterized as an interaction of a nucleophile with an electrophile, this chemistry is highly related to the recent research of polyhalides or polypseudohalides in general , . So do the one‐dimensional chains compare well with zig‐zag shaped [X 8 ] 2– (X = Cl, Br, I) or [I(Br 4 )] –[54] anions, tetragonal shaped architectures compare well with the [Cl(I 2 ) 4 ] –[55] or [I 5 Br 2 ] –[56] anion and iodosulfite [ISO 2 ] – is most likely analogous to the simple trihalides [X 3 ] – (X = Cl, Br, I), , and also mixed (pseudo‐)halides such as [Br(BrCN)] – (arbitrarily chosen) . The non‐planar aggregate [I 2 (SO 2 ) 5 ] 2– is highly related to for example [Cl 12 ] 2– which represents a non‐planar building‐block of a three‐dimensional network in [NMe 3 Ph] 2 [Cl 12 ] …”

“…[49,50] So do the one-dimensional chains compare well with zig-zag shaped [X 8 ] 2-(X = Cl, Br, I) [51][52][53] or [I(Br 4 )] - [54] anions, tetragonal shaped architectures compare well with the [Cl(I 2 ) 4 ] - [55] or [I 5 Br 2 ] - [56] anion and iodosulfite [ISO 2 ]is most likely analogous to the simple trihalides [X 3 ] -(X = Cl, Br, I) [52,57,58] and also mixed (pseudo-)halides such as [Br(BrCN)] -(arbitrarily chosen). [59] The non-planar aggregate [I 2 (SO 2 ) 5 ] 2is highly related to for example [Cl 12 ] 2which represents a nonplanar building-block of a three-dimensional network in [NMe 3 Ph] 2 [Cl 12 ]. [60] These are just a few parallels but they demonstrate that the structural motifs which are obtained in a lewis acid-base chemistry including halides and SO 2 has the potential to form various species in the form of [X m (SO 2 ) n ] mas it is well-known for polyhalides or poly-pseudohalides such as…”

Salze von HCN‐Cyanid‐Aggregaten: [CN(HCN)2]− und [CN(HCN)3]−

“…[62] Die Gruppe von Fehlhammer isolierte [M- [63] Erst kürzlich berichtete die Gruppe von Riedel über die Isolierung von Pseudohalogen-Halogeniden des Typs [Br(BrCN)] À und [Br(BrCN) 3 ] À . [64] Da wir in jüngster Zeit die Stabilisierung von HCN-Dimeren durch starke Lewis-Säuren beobachtet haben, untersuchten wir anschließend die Reaktion zwischen Lewis-Basen wie CN À und HCN, um Salze mit HCN-Cyanid-Aggregaten des Typs [CN(HCN) n ] À (n = 1, 2, 3 …) zu isolieren. Die grçßten Probleme bei der Verwendung von reinem polarem HCN (l) (m = 2.98 D) [65] sind seine hohe Toxizität (180-270 ppm sind tçdlich), [66] der niedrige Siedepunkt (Sdp.…”

“…Die Gruppe von Fehlhammer isolierte [M‐CN⋅⋅⋅H⋅⋅⋅NC‐M] − ‐Komplexe (M=Cr(CO) 5 ) durch Reaktion von [Ph 4 As][Cr(CN)(CO) 5 ] mit [Cr(CO) 5 CNH] . Erst kürzlich berichtete die Gruppe von Riedel über die Isolierung von Pseudohalogen‐Halogeniden des Typs [Br(BrCN)] − und [Br(BrCN) 3 ] − . Da wir in jüngster Zeit die Stabilisierung von HCN‐Dimeren durch starke Lewis‐Säuren beobachtet haben, untersuchten wir anschließend die Reaktion zwischen Lewis‐Basen wie CN − und HCN, um Salze mit HCN‐Cyanid‐Aggregaten des Typs [CN(HCN) n ] − ( n= 1, 2, 3 …) zu isolieren.…”