Search results for "BIP"

Ordering the amorphous – Structures in PBD LED materials

2012

Abstract The class of 2,5 disubstituted-1,3,4-oxadiazoles containing a biphenyl unit on one side is intensively used as electron transport materials to enhance the performance of organic light emitting diodes (OLEDs). In contrast to the ongoing research on these materials insights in their structure-property relationships are still incomplete. To overcome the structural tentativeness and ambiguities the crystal structures of 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, that of the related compound 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole and of 2-(4-biphenylyl)-5-(2,6-dimethylphenyl)-1,3,4-oxadiazole are determined. A comparison with the results of GAUSSIAN03 calculations and…

Phenol Derivatives in Ruthenium-Catalyzed C-H Arylation: A General Synthetic Access to Azole-Based Congested Polyaromatics

2018

Assembly of a planar, tricyclic B4N8 framework with s-indacene structure.

2007

A neutral, formally 16pi-electron, tricyclic tetrahydrazidotetraborane was obtained in a two-step procedure involving self-assembly of a dilithiodiborate with B(4)N(8) framework and subsequent oxidation of the phenylborate moieties to boranes and biphenyl using Fe(II) as an oxidant.

Redox-active crown ethers derived from biphenyl. Electrochemical and spectroscopic study of binding processes with alkali, alkali-earth and mercury s…

1998

Abstract Three new electroactive ligands, 3a, 3b and 3c, that contain the biphenyl frameworks in their structure were prepared. These new ligands presented three interesting characteristics: 1) they exhibited a reversible oxidation, 2) the oxidation induced a conformational change in the crown moiety and 3) they had two different coordination centers, the crown ether and the dimethylamino groups. Electrochemical and spectroscopic studies using alkali, alkali-earth and mercury salts were carried out.

Biphenyl macrolactams in anion complexation. Selective naked-eye fluoride recognition

2004

Two colorimetric anion sensors 1 and 2 allow for the selective differentiation of fluoride in the presence of other anions. Two different types of species have been observed in the complexation process, one of them is a co-ordination complex and the other is a salt generated by ligand deprotonation. The deprotonation reaction induces a conformational change, giving rise to a symmetrical species. This species is responsible for colour development. Ligand 3 has a similar structure and does not give rise to any colour modification due to presence of the dimethylamino groups in the biphenyl moiety. The X-ray structure of ligand 2 is also reported and compared with that of ligand 1, that had bee…

Synthesis of Hydroquinoid C- and O-Biphenyl Disaccharides by Chromium-Templated Benzannulation Reactions

2003

Organometallic monosaccharides 6−10 containing a chromium styrylcarbene skeleton have been synthesized in quantitative yield from O-glycoside methylcarbene complexes 1−5 bearing diisopropylidene-protected glucose, mannose, galactose, or fructose in a trans-selective aldol condensation with benzaldehyde. These compounds undergo a chromium-templated benzannulation upon reaction with ethynyl glucoside to give diastereoisomeric mixtures of Cr(CO)3 complexes. The differences in their thermodynamic stability was exploited in a diastereoselective synthesis of hydroquinoid biphenyl disaccharides 12−16 in 67−88% yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

A polyazacyclophane containing two biphenyl subunits as a versatile cation and anion receptor

2002

Abstract The synthesis, protonation behaviour and coordination capabilities towards Cu 2+ , Zn 2+ and towards the nucleotides ATP and ADP of a cyclophane ditopic receptor 2,6,10,23,27,31-hexaaza[11,11](2,2′)biphenylophane containing two 2,2′-biphenylene spacers linked to the ends of 1,5,9-triazanonane chains are presented.

1978

Cation and anion fluorescent and electrochemical sensors derived from 4,4′-substituted biphenyl

2005

Five new fluorescent macrocyclic ligands derived from biphenyl are described. These new compounds can be used in cation and anion recognition and sensing. Their fluorescent and electrochemical properties are studied and the influence of the biphenyl conformation on these properties is considered. The X-ray single crystal structure of one of the described ligands has been determined.

Polyazapodands Derived from Biphenyl. Study of their Behaviour as Conformationally Regulated Fluorescent Sensors

2004

Eight new polyazapodands containing a 4,4′-substituted biphenyl moiety have been synthesised. Four (7, 8, 9 and 11) are functionalised on positions 4 and 4′ with a nitro group and four (1, 2, 3 and 10) with a dimethylamino substituent. Comparison of the emission behaviour of 1, 2, 3 with that of the reference compounds 10 and tetramthylbenzidine, clearly suggests that a modification in the dihedral angle between the biphenyl rings is an important factor in determining the fluorescent response of the molecule. The fluorescence is pH dependent, due to the formation of intramolecular hydrogen bonds between protonated aliphatic nitrogens and a carbonyl oxygen, which influences the aforementione…