Metal-coordinated distibene and dibismuthene dications – isoelectronic analogues of butadiene dications

Abstract

We report the synthesis and solid-state structures of DMAP-coordinated ([L(DMAP)GaPn]2[OTf]2; Pn = Sb 3, Bi 4) and base-free dipnictene dications ([LGaPn]2[BArFx]2, Pn = Sb: x = 24, 5a; 20, 5b;...

From Neutral Diarsenes to Diarsene Radical Ions and Diarsene Dications

“…MeOTf was found to attack the electron lone‐pair of the Ga‐bonded methoxy group, resulting in the elimination of dimethyl ether (DME) and formation of the triflate‐substituted neutral diarsene [L(TfO)GaAs] 2 ( 5 , Scheme 3). A similar reaction has been reported for L(Me 2 N)Ga‐substituted distibenes, but no excess of MeOTf was required since DME is less nucleophilic than NMe 3 [19] . The reactions of diarsene 4 with either one or two equivalents of Me NHC at ambient temperature occurred with rapid formation of the carbene‐coordinated neutral diarsene L(MeO)GaAsAs( Me NHC)Ga(OMe)L ( 6 ) as was demonstrated by in situ 1 H NMR spectroscopy.…”

“…A similar reaction has been reported for L(Me 2 N)Ga-substituted distibenes, but no excess of MeOTf was required since DME is less nucleophilic than NMe 3 . [19] The reactions of diarsene 4 with either one or two equivalents of Me NHC at ambient temperature occurred with rapid formation of the carbene-coordinated neutral diarsene L(MeO)GaAsAs( Me NHC)Ga(OMe)L (6) as was demonstrated by in situ 1 H NMR spectroscopy. In contrast, the reaction with the second equivalent of Me NHC at 55 °C for several days resulted in the cleavage of the AsÀ As bond and formation of the NHC-coordinated arsinidene L(MeO)-GaAs Me NHC (7, Figure S40).…”

“…Supporting Information Available: Detailed synthetic procedures and analytical data of 1-11: 1 H, 13 C, 19 ) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.…”

“…They can be further oxidized to the corresponding closed‐shell dications [17,18] . In addition, we have recently reported the synthesis of distibene ( VIII ) and dibismuthene ( IX ) dications, which together with dipnictene dications coordinated by anionic carbenes ((WCA‐IDipp) 2 Pn 2 , Pn=P−Bi, WCA=B(C 6 F 5 ) 3 , IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) represent rare examples of structurally characterized dipnictene dications [19,20] …”

“…represent rare examples of structurally characterized dipnictene dications. [19,20] We are generally interested in the synthesis and reactivity of unsaturated heavy dipnictenes [21][22][23] and metallapnictenes of group 13 metals [24,25,26] containing PnÀ Pn and PnÀ M double bonds. Unfortunately, L(X)Ga-substituted diarsenes have only been accessible in low yields via oxidative addition reactions of AsX 3 (X = halide, alkoxide, amide) with two equivalents of LGa, [27] thus preventing them from detailed reactivity studies.…”