Search results for "CRYSTALLOGRAPHY"
showing 10 items of 18525 documents
Melting point, molecular symmetry and aggregation of tetrachlorobenzene isomers: the role of halogen bonding
2018
Tetrachlorobenzenes represent one of the best known, but not yet fully understood, group of isomers of the structure–melting point relationship. The differences in melting temperatures of these structurally related compounds were rationalized in terms of the hierarchy and nature of formed noncovalent interactions, and the molecular aggregation that is influenced by molecular symmetry. The highest melting point is associated with the highly symmetric 1,2,4,5-tetrachlorobenzene isomer. The structures of less symmetrical 1,2,3,4-tetrachlorobenzene and 1,2,3,5-tetrachlorobenzene, determined at 270 and 90 K, show a distinct pattern of halogen bonds, characterized by the different numbers and typ…
CCDC 874635: Experimental Crystal Structure Determination
2013
Related Article: K.Mack, A.W.von Leupoldt, C.Forster, M.Ezhevskaya, D.Hinderberger, K.W.Klinkhammer, K.Heinze|2012|Inorg.Chem.|51|7851|doi:10.1021/ic300929g
CCDC 874634: Experimental Crystal Structure Determination
2013
Related Article: K.Mack, A.W.von Leupoldt, C.Forster, M.Ezhevskaya, D.Hinderberger, K.W.Klinkhammer, K.Heinze|2012|Inorg.Chem.|51|7851|doi:10.1021/ic300929g
CCDC 650418: Experimental Crystal Structure Determination
2003
Related Article: Y.Jacquot, B.Refouvelet, O.Blacque, M.M.Kubicki, A.Xicluna|2001|C.R.Acad.Sci.,Ser.IIc:Chim.|4|375|doi:10.1016/S1387-1609(01)01243-9
CCDC 635391: Experimental Crystal Structure Determination
2009
Related Article: S.Bredeau, E.Ortega, G.Delmas, P.Richard, R.Frohlich, B.Donnadieu, G.Kehr, N.Pirio, G.Erker, P.Meunier|2009|Organometallics|28|181|doi:10.1021/om800512u
Phosphorus-Chalcogen Ring Expansion and Metal Coordination
2017
The reactivity of 4-membered (RPCh)2 rings (Ch = S, Se) that contain phosphorus in the +3 oxidation state is reported. These compounds undergo ring expansion to (RPCh)3 with the addition of a Lewis base. The 6-membered rings were found to be more stable than the 4-membered precursors, and the mechanism of their formation was investigated experimentally and by density functional theory calculations. The computational work identified two plausible mechanisms involving a phosphinidene chalcogenide intermediate, either as a free species or stabilized by a suitable base. Both the 4- and 6-membered rings were found to react with coinage metals, giving the same products: (RPCh)3 rings bound to the…
Zn2+ and Cu2+ complexes of a fluorescent scorpiand-type oxadiazole azamacrocyclic ligand: crystal structures, solution studies and optical properties
2020
A ligand comprised of a macrocyclic pyridinophane core having a pendant arm containing a secondary amine group linked through a methylene spacer to a pyridyl–oxadiazole–phenyl (PyPD) fluorescent system has been prepared (L). The crystal structures of [ZnL](ClO4)2 and [CuL](ClO4)2 show that M2+ is coordinated to all the nitrogen atoms of the macrocyclic core, the secondary amine of the pendant arm and the nitrogen atom of the pyridine group of the fluorescent moiety, the latter bond being clearly weaker than the one with the pyridine of the macrocycle. Solution studies showed the formation of a highly stable Cu2+ complex with 1 : 1 stoichiometry, whereas with Zn2+ least stable complexes were…
Heads or Tails? Sandwich-Type Metallocomplexes of Hexakis(2,3-di-O-methyl)-α-cyclodextrin
2020
Native and synthetically modified cyclodextrins (CDs) are useful building blocks in construction of large coordination complexes and porous materials with various applications. Sandwich-type complexes (STCs) are one of the important groups in this area. Usually, coordination of secondary hydroxyls or the “head” portal of native CD molecules to a notional multinuclear ring of metal cations leads to formation of head-to-head STCs. Our study introduces a new CD-ligand, hexakis(2,3-di-O-methyl)-α-cyclodextrin, which enables formation of intriguing head-to-head, but also novel tail-to-tail STCs. Homometallic silver-based head-to-head STCs, AgPF6-STC and AgClO4-STC, were obtained by coordination …
CCDC 2149627: Experimental Crystal Structure Determination
2022
Related Article: Adrian Laviós, Amparo Sanz-Marco, Carlos Vila, M. Carmen Muñoz, José R. Pedro, Gonzalo Blay|2022|Org.Lett.|24|2149|doi:10.1021/acs.orglett.2c00427
CCDC 985005: Experimental Crystal Structure Determination
2014
Related Article: Frank Bohland, Irina Erlin, Lukas Platte, Maike Schröder, Dieter Schollmeyer, Udo Nubbemeyer|2014|Eur.J.Org.Chem.|2014|6272|doi:10.1002/ejoc.201402720