Unexpected reactions of NHC*—Cu(I) and —Ag(I) bromides with potassium thio- or seleno­cyanate

The reactions of N-heterocyclic carbene Cu(I) and Ag(I) halides with potassium thio- or seleno­cyanate gave unexpected products. The attempted substitution reaction of bromido­(1,3-dibenzyl-4,5-di­phenyl­imidazol-2-yl­idene)silver (NHC*—Ag—Br) with KSCN yielded bis­[bis­(1,3-dibenzyl-4,5-di­phenyl­imidazol-2-yl­idene)silver(I)] tris­(thio­cyanato)­argentate(I) diethyl ether disolvate, [Ag(C(29)H(24)N(2))(2)][Ag(NCS)(3)]·2C(4)H(10)O or [NHC*(2)Ag](2)[Ag(SCN)(3)]·2Et(2)O, (1), while reaction with KSeCN led to bis­(μ-1,3-dibenzyl-4,5-diphenyl-2-seleno­imidazole-κ(2) Se:Se)bis­[bromido­(1,3-dibenzyl-4,5-diphenyl-2-seleno­imid­azole-κSe)silver(I)] di­chloro­methane hexa­solvate, [Ag(2)Br(2)(C(29)H(24)N(2)Se)(4)]·6CH(2)Cl(2) or (NHC*Se)(4)Ag(2)Br(2)·6CH(2)Cl(2), (2), via oxidation of the NHC* fragment to 2-seleno­imidazole. This oxidation was observed again in the reaction of NHC*—Cu—Br with KSeCN, yielding catena-poly[[[(1,3-dibenzyl-4,5-diphenyl-2-seleno­imidazole-κSe)copper(I)]-μ-cyanido-κ(2) C:N] aceto­nitrile monosolvate], {[Cu(CN)(C(29)H(24)N(2)Se)]·C(2)H(3)N}(n) or NHC*Se—CuCN·CH(3)CN, (3). Compound (1) represents an organic/inorganic salt with Ag(I) in a linear coordination in each of the two cations and in a trigonal coordination in the anion, accompanied by diethyl ether solvent mol­ecules. The tri-blade boomerang-shaped complex anion [Ag(SCN)(3)](2−) present in (1) is characterized by X-ray diffraction for the first time. Compound (2) comprises an isolated centrosymmetric mol­ecule with Ag(I) in a distorted tetra­hedral BrSe(3) coordination, together with di­chloro­methane solvent mol­ecules. Compound (3) exhibits a linear polymeric (1) (∞)[Cu—C≡N—Cu—] chain structure with a seleno­imidazole moiety additionally coordinating to each Cu(I) atom, and completed by aceto­nitrile solvent mol­ecules. Electron densities associated with an additional ether solvent mol­ecule in (1) and two additional di­chloro­methane solvent mol­ecules in (2) were removed with the SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9–18] in PLATON.