Binding, Release and Functionalization of Intact Pnictogen Tetrahedra Coordinated to Dicopper Complexes

The bridging MeCN ligand in the dicopper(I) complexes [(DPFN)Cu(2)(μ,η(1) : η(1)‐MeCN)][X](2) (X=weakly coordinating anion, NTf(2) (1 a), FAl[OC(6)F(10)(C(6)F(5))](3) (1 b), Al[OC(CF(3))(3)](4) (1 c)) was replaced by white phosphorus (P(4)) or yellow arsenic (As(4)) to yield [(DPFN)Cu(2)(μ,η(2) : η(2)‐E(4))][X](2) (E=P (2 a–c), As (3 a–c)). The molecular structures in the solid state reveal novel coordination modes for E(4) tetrahedra bonded to coinage metal ions. Experimental data and quantum chemical computations provide information concerning perturbations to the bonding in coordinated E(4) tetrahedra. Reactions with N‐heterocyclic carbenes (NHCs) led to replacement of the E(4) tetrahedra with release of P(4) or As(4) and formation of [(DPFN)Cu(2)(μ,η(1) : η(1)‐(Me)NHC)][X](2) (4 a,b) or to an opening of one E−E bond leading to an unusual E(4) butterfly structural motif in [(DPFN)Cu(2)(μ,η(1) : η(1)‐E(4) (Dipp)NHC)][X](2) (E=P (5 a,b), E=As (6)). With a cyclic alkyl amino carbene ((Et)CAAC), cleavage of two As−As bonds was observed to give two isomers of [(DPFN)Cu(2)(μ,η(2) : η(2)‐As(4) (Et)CAAC)][X](2) (7 a,b) with an unusual As(4)‐triangle+1 unit.