Hydropnictination Reactions of Carbodiimides and Isocyanates with Protonated Heptaphosphide and Heptaarsenide Zintl Ions

By following a similar procedure to that employed for the synthesis of [HP 7 ] 2– ( 1 ), the synthesis and characterization of the hydrogenheptaarsenide dianion [HAs 7 ] 2– ( 2 ) was achieved. Building on previous research that has shown that [HP 7 ] 2– can react with carbodiimides to yield amidine‐functionalized cluster anions [P 7 C(NHR)(NR)] 2– , we have found that the analogous hydroarsination reactions are also possible by reaction of 2 with RC=N=CR to yield [As 7 C(NHR)(NR)] 2– [R = Dipp ( 3 ), i Pr ( 4 ) and Cy ( 5 ); Dipp = 2,6‐diisopropylphenyl]. Furthermore, we also demonstrate that such hydropnictination reactions can be extended to other heteroallenes such as isocyanates (O=C=NAd; Ad = adamantyl) to afford the amide‐derivatized cluster anions [E 7 C(CO)(NHAd)] 2– [E = P ( 6 ) and As ( 7 )]. All new compounds were characterized by multinuclear NMR spectroscopy, elemental analyses and electrospray mass spectrometry. Clusters 2 , 4 , 6 and 7 were also characterized by single‐crystal X‐ray diffraction of [K(18‐crown‐6)] 2 [ 2 ], [K(18‐crown‐6)] 2 [ 4 ], [K(18‐crown‐6)] 2 [ 6 ] · py (py = pyridine) and [K(18‐crown‐6)] 2 [ 7 ] · py. Crystal structures confirming composition and connectivity were also obtained for anions 3 and 5 .