Cu(i) and Ag(i) complexes of 7,10-bis-N-heterocycle-diazafluoranthenes: programmed molecular grids?†
Reactions of 7,10-disubstituted diazafluoranthene derivatives with three different silver(I) salts AgX (X = [PF6]−, [SbF6]−, [CB11HCl11]−) and [Cu(CH3CN)4]PF6 afforded complexes exhibiting five different motifs. The crystal structures of the free ligands and nine new complexes from this series of reactions are reported. The use of 2,5-di-tert-butyl-7,10-di(pyridin-2-yl)-8,9-diazafluoranthene as a ligand leads to the formation of the tetranuclear compounds [Ag4(C32H30N4)4][PF6]4·3C6H6·4MeCN, [Ag4(C32H30N4)4][SbF6]4·4C5H12 and [Cu4(C32H30N4)4][PF6]4·8C3H6O, which exhibit “propeller” and saddle-type geometry, respectively, as well as a dinuclear complex [Ag2(C32H30N4)2][CHB11Cl11]2·4C6H4Cl2·CH2Cl2. The reactions involving the less sterically hindered 2,5-di-tert-butyl-7,10-di-(pyrimidin-2-yl)-8,9-diazafluoranthene and 2,5-di-tert-butyl-7,10-di(thiazol-2-yl)-8,9-diazafluoranthene afforded crystals of the dinuclear complexes [Ag2(C30H28N6)2][PF6]2·0.5CH2Cl2·0.5C6H5Cl·0.5C6H12, [Ag2(C30H28N6)2][SbF6]2·C3H6O·0.5C6H14·0.5C6H6, the polymeric species [Ag2(C28H26N4S2)2]n·2n[PF6]n·nC3H6O and the tetranuclear compounds [Cu4(C26H25N4S2)4][PF6]4·2CHCl3·2C3H6O and [Cu4(C30H28N6)4][PF6]4·2.17H2O, which possess saddle and grid-like architectures, respectively. Conformational analysis of the free ligands showed that they exhibit N–C–C–N torsion angles ranging from syn clinal (58°) to fully anti-periplanar conformations; the syn clinal conformation dominates in the complexes. The relative energies of the possible structural conformations of the synthesized ligands, as well as of oxazole disubstituted diazafluoranthenes, were calculated using density functional theory at the B97D/Def2-TZVPP level of theory.