Molecular orbital studies on brominated diphenyl ethers. Part II—reactivity and quantitative structure–activity (property) relationships

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants and are increasingly turning up in the environment. Their structural similarities to polychlorinated biphenyls and thyroid hormones suggest they may be a risk to human health. The present study examines the reactivity of brominated diphenyl ethers (BDEs) on the basis of the electronic structures as calculated by semiempirical AM1 self-consistent field molecular orbital (SCF-MO) method. Frontier orbital energies were used to elucidate the reactivity of BDEs in electrophilic, nucleophilic and photolytic reactions. From an examination of the frontier electron densities, the regioselectivity, or orientation, of metabolic…

Molecular orbital studies on brominated diphenyl ethers. Part I—conformational properties

Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants and quantities in the environment are on the rise. Because they are structurally related to polychlorinated biphenyls and also to thyroid hormones, there is serious concern that PBDEs may pose a danger to human health. Knowledge of their conformational properties is key to assessing their environmental fate and risk. The conformational properties of PBDEs were investigated by quantum chemical methods including semiempirical self-consistent field molecular orbital (SCF-MO), ab initio SCF-MO and density functional theory (DFT). Conformational analyses of model congeners 2,2',4,6'-tetrabromodiphenyl ether and 2…

1H and13C NMR spectroscopy of brominated diphenyl ethers. A multiple linear regression analysis

The 1H and 13C NMR chemical shifts and 1H, 1H coupling constants of 27 brominated diphenyl ethers are reported. The increment models for the bromine substituent effects on the 1H and 13C NMR chemical shifts were constructed based on a multiple linear regression analysis. In addition to the single substituent effects, two particle increments and corrective terms for conformational effects are included in these models in order to obtain a reliable prediction of chemical shifts. Copyright © 2000 John Wiley & Sons, Ltd.

4-Bromophenyl 2,3,4,5,6-pentabromophenyl ether

The title compound, C12H4Br6O, belongs to a group of flame retardants known as polybrominated di­phenyl ethers (PBDE). Intermolecular Br⋯Br contacts in the bc plane give a sheet-like character to the structure of the title compound.

Phenyl 2,4,6-tribromophenyl ether

The title compound, C12H7Br3O, is the third well characterized of a total of 209 different brominated di­phenyl ethers. The bromine-substituted rings pack in the crystal in a common plane with the same ring from symmetry-related neighbouring mol­ecules. The short Br⋯Br contact distance [3.519 (2) A], together with a pair of considerably longer Br⋯Br contact distances [3.966 (2) A], may be part of a model describing this packing.

2,4-Dibromophenyl 2,6-dibromophenyl ether

The title compound, C12H6Br4O, is the fourth well characterized of a total of potentially 209 different brominated di­phenyl ethers. Salient intermolecular interactions are between ether O and aromatic C atoms, and between a bromine substituent and the aromatic ring system.

4-Bromophenyl 2,4-dibromophenyl ether

The title compound, C12H7Br3O, belongs to a group of flame retardants known as polybrominated di­phenyl ethers (PBDE). Salient features of the packing of the title compound are infinite intermolecular Br⋯Br contact chains along the b direction.

Ab initio study of halogenated diphenyl ethers. NMR chemical shift prediction

4-Bromophenyl 2,6-dibromophenyl ether

The title compound, C12H7Br3O, is an example of a compound related to some important flame retardants, e.g. decabromodi­phenyl ether. Salient intermolecular interactions are the short contacts between the bromine substituents and the C atoms of the aromatic ring system. The mol­ecules make up chains through these short Br⋯C contacts; these chains pack into sheets parallel to the ab plane, and copies of these sheets pack on to each other along the c axis in a tweed-like pattern.

2,3,4,5,6-Pentabromophenyl phenyl ether

The title compound, C12H5Br5O, belongs to a group of flame retardants known as polybrominated di­phenyl ethers (PBDE). Salient features of the packing are stabilization due to intermolecular Br⋯Br contacts in the ab plane and aromatic intermolecular contacts along the c direction.

CCDC 189413: Experimental Crystal Structure Determination

Related Article: L.Eriksson, Jiwei Hu|2002|Acta Crystallogr.,Sect.E:Struct.Rep.Online|58|o696|doi:10.1107/S1600536802008693

CCDC 198974: Experimental Crystal Structure Determination

Related Article: L.Eriksson, Jiwei Hu|2002|Acta Crystallogr.,Sect.E:Struct.Rep.Online|58|o1147|doi:10.1107/S1600536802016926

CCDC 182613: Experimental Crystal Structure Determination

Related Article: J.Eriksson, L.Eriksson, Jiwei Hu|2002|Acta Crystallogr.,Sect.E:Struct.Rep.Online|58|o263|doi:10.1107/S1600536802002301

CCDC 175356: Experimental Crystal Structure Determination

Related Article: L.Eriksson, Jiwei Hu|2001|Acta Crystallogr.,Sect.E:Struct.Rep.Online|57|o930|doi:10.1107/S1600536801014702

CCDC 182646: Experimental Crystal Structure Determination

Related Article: J.Eriksson, L.Eriksson, Jiwei Hu|2002|Acta Crystallogr.,Sect.E:Struct.Rep.Online|58|o347|doi:10.1107/S1600536802002738

CCDC 189917: Experimental Crystal Structure Determination

Related Article: L.Eriksson, Jiwei Hu|2002|Acta Crystallogr.,Sect.E:Struct.Rep.Online|58|o794|doi:10.1107/S1600536802010942