Crystal structures of two novel iron isocyanides from the reaction of 2,6-di-methyl-phenyl isocyanide, CNXyl, with bis-(anthracene)ferrate(-1).

The reaction of the [K(18-crown-6)(thf)2]1+ (thf is tetra-hydro-furan) salt of bis-(anthracene)ferrate(-1), or [Fe(C14H10)2]-, with 2,6-di-methyl-phenyl isocyan-ide (CNX-yl) in thf resulted in the formation of two new iron isocyanide complexes, namely, [(1,2,3,4-η)-anthracene]tris-(2,6-di-methyl-phenyl isocyanide)iron, [Fe(C14H10)(C9H9N)3] or [Fe(1,2,3,4-η-C14H10)(CNX-yl)3], and {5,6-bis-(2,6-di-methyl-anilino)-3-(2,6-di-methyl-phen-yl)-1,2,7-tris-[(2,6-di-methyl-phen-yl)imino]-3-azoniahept-3-ene-1,4,7-triido}tris-(2,6-di-methyl-phenyl isocyanide)iron tetra-hydro-furan disolvate, [Fe(C54H56N6)(C9H9N)3]·2C4H8O or [Fe(C54H56N6)(CNX-yl)3]·2C4H8O, which were characterized by single-crystal X-ray diffraction. The former is likely an inter-mediate along the path to the known homoleptic [Fe(CNX-yl)5], while the latter contains a tridentate ligand that is formed from the 'coupling' of six CNXyl ligands. A third crystal structure from this reaction, (7-methyl-indol-1-ido-κN)(1,4,7,10,13,16-hexa-oxa-cyclo-octa-decane-κ6 O)potassium, [K(C9H8N)(C12H24O6)] or [K(C9H8N)(18-crown-6)], contains a 7-methyl-indol-1-ide anion, in which one CNXyl ligand has shed a proton during its reductive cyclization. © Brennessel and Ellis 2022.