Synthesis and spectroscopy of an oligophenyl based cruciform with remarkable pi-pi assisted folding.

A facile route has been developed for the preparation of a new family of oligophenyls based on a 2,5,2',5'-tetra-aryl substituted biphenyl structural motif. The cruciform terphenyl dimer 2,5,2',5'-tetra(4-tert-butylphenyl)-1,1'-biphenyl () has been prepared in a two step protocol as a representative of this interesting class of materials. The thermal behaviour of the cruciform was analysed by DSC and shows that forms an amorphous glass when cooled from the isotropic melt.

Hydrogen bonding in 1-carbamoylguanidinium methylphosphonate monohydrate.

The title compound, C(2)H(7)N(4)O(+).CH(4)O(3)P(-).H(2)O, crystallized with one carbamoylguanidinium cation, one methylphosphonate anion and one water molecule in the asymmetric unit.

Preparation and NMR Spectra of Difluoromethylated Silver(I) and Silver(III) Compounds. Structure of [PNP][Ag(CF(2)H)(4)].

The thermally unstable [Ag(CF(2)H)(2)](-) moiety is obtained in solution by reaction of silver(I) salts with Cd(CF(2)H)(2) in DMF/diglyme at -80 degrees C. Oxidation with I(2) leads to the argentate(III) [Ag(CF(2)H)(4)](-), which has been isolated as its PNP salt. According to DSC/TG analysis, the exothermic decomposition of this air-stable salt proceeds in two steps at 121 and 150 degrees C with formal elimination of one and three CFH units, respectively.

Preparation and NMR Spectra of the (Trifluoromethyl)argentates(III) [Ag(CF(3))(n)X(4-n)](-), with X = CN (n = 1-3), CH(3), C&tbd1;CC(6)H(11), Cl, Br (n = 2, 3), and I (n = 3), and of Related Silver(III) Compounds. Structures of [PPh(4)][trans-Ag(CF(3))(2)(CN)(2)] and [PPh(4)][Ag(CF(3))(3)(CH(3))].

Trifluoromethylation of [Ag(CN)(2)](-) with (CF(3))(2)Cd.diglyme yields [Ag(CF(3))(CN)](-). The anion is readily oxidized by bromine to the argentates(III), [Ag(CF(3))(n)(CN)(4-n)](-), n = 1-4.