title: 9-Anthracenyl-substituted pyridyl enones revisited: photoisomerism in ligands and silver(I) complexes.
abstract: In solution, (E) to (Z)-isomerism is facile both in 3-(9-anthracenyl)-1-(pyridin-4-yl)propenone, 2, and in its silver(I) complex [Ag(2)(2)](+). The crystal structures of (E)-2, (Z)-2 and [Ag{(E)-2}(2)][SbF(6)] are presented, and the roles of edge-to-face and face-to-face π-interactions in the lattice are discussed. Solution NMR spectroscopic data suggest that the driving force for (E) to (Z) isomerization is intramolecular π-stacking of the pyridine and anthracene domains. The reversed enone 3-(9-anthracenyl)-1-(pyridin-4-yl)propen-3-one, (E)-3, and the silver(I) complex [Ag{(E)-3}(2)][SbF(6)] have been prepared and characterized, including a single crystal X-ray determination of the latter. Surprisingly, no π-stacking between anthracene or pyridine domains is observed in the solid state, and the crystal packing is dominated by Ag···F, CH(anthracene)···π-pyridine and CH···F interactions. In contrast to (E)-2 and [Ag{(E)-2}(2)](+), neither (E)-3 nor [Ag{(E)-3}(2)](+) undergoes photoisomerization in solution.
authors.affiliation: Department of Chemistry, University of Basel, Spitalstrassse 51, CH-4056 Basel, Switzerland. edwin.constable@unibas.ch
authors.forename: Edwin C
authors.initials: EC
authors.lastname: Constable
authors.forename: Guoqi
authors.initials: G
authors.lastname: Zhang
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Housecroft
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Zampese
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000873:Anthracenes / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010782:Photolysis; D011725:Pyridines / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D000873:Anthracenes; D007659:Ketones; D008024:Ligands; D009942:Organometallic Compounds; D011725:Pyridines; D012834:Silver; C034020:anthracene; C023666:pyridine