title: Synthetic and structural studies of 1,8-chalcogen naphthalene derivatives.
abstract: Four novel 1,8-disubstituted naphthalene derivatives 4-7 that contain chalcogen atoms occupying the peri positions have been prepared and fully characterised by using X-ray crystallography, multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular distortion due to noncovalent substituent interactions was studied as a function of the bulk of the interacting chalcogen atoms and the size and nature of the alkyl group attached to them. X-ray data for 4-7 was compared to the series of known 1,8-bis(phenylchalcogeno)naphthalenes 1-3, which were themselves prepared from novel synthetic routes. A general increase in the E...E' distance was observed for molecules containing bulkier atoms at the peri positions. The decreased S...S distance from phenyl-1 and ethyl-4 analogues is ascribed to a weaker chalcogen lone pair-lone pair repulsion acting in the ethyl analogue due to the presence of two equatorial S(naphthyl) ring conformations. Two novel peri-substituted naphthalene sulfoxides of 1, Nap(O=SPh)(SPh) 8 and Nap(O=SPh)(2) 9, which contain different valence states of sulfur, were prepared and fully characterised by using X-ray crystallography and multinuclear NMR spectroscopy, IR spectroscopy and MS. Molecular structures were analysed by using naphthalene ring torsions, peri-atom displacement, splay angle magnitude, S...S interactions, aromatic ring orientations and quasi-linear O=S...S arrangements. The axial S(naphthyl) rings in 8 and 9 are unfavourable for S...S contacts due to stronger chalcogen lone pair-lone pair repulsion. Although quasi-linear O=S...S alignments suggest attractive interaction is conceivable, analysis of the B3LYP wavefunctions affords no evidence for direct bonding interactions between the S atoms.
authors.affiliation: School of Chemistry, University of St Andrews, St Andrews, Fife, KY16 9ST UK.
authors.forename: Fergus R
authors.initials: FR
authors.lastname: Knight
authors.forename: Amy L
authors.initials: AL
authors.lastname: Fuller
authors.forename: Michael
authors.initials: M
authors.lastname: Bühl
authors.forename: Alexandra M Z
authors.initials: AM
authors.lastname: Slawin
authors.forename: J Derek
authors.initials: JD
authors.lastname: Woollins
mesh_terms: D018011:Chalcogens / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009281:Naphthalenes / Q000138:chemical synthesis* / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared; D013329:Structure-Activity Relationship; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: C550954:1,8-chalcogen naphthalene; D018011:Chalcogens; D009281:Naphthalenes; D013438:Sulfhydryl Compounds