Aromatic ligand

It has been observed that the best neutral cation carriers have the synclinal arrangement of binding atoms in the backbone (see 7.2). Syntheses of both an aliphatic and aromatic ligand are shown below in Eqs. (7.12) and (7.13). 

Macrocyclic ligands such as crown ethers have been widely used for metal ion extraction, the basis for metal ion selectivity being the structure and cavity size of the crown ether. The hydrophobicity of the ligand can be adjusted by attachment of alkyl or aromatic ligands to the crown. Impressive results have been obtained with dicyclohexano-18-crown-6 as an extractant for Sr in [RMIM][(CF3S02)2N] IL/aque-... 

The reaction was extended to PhCH2X (X = Cl or Br) which gives the hexa(phenyl-ethyl)benzene complex. The new free aromatic ligand is easily disengaged by photolysis in acetonitrile [76a] Eq. (20). This line of research is now offering us the perspective of making new discotic liquid crystals using suitably substituted... 

L = neutral monodentate ligand L-L = neutral bidentate ligand X = halide ligand Ar = aromatic ligand Cp = cyclopentadiene. 

Scheme 1.23 Test reaction with P-phosphino sulfoxide and Af-diphenylphosphano nitrogen-containing five-membered aromatic ligands.

Planar coordination compounds with aromatic ligands, especially those having extended 7r-systems, show 7r-7r interactions in the solid state. The ligands shown in Figure 8 form complexes with silver(I) which have a supramolecular structure through 7r-7r interactions.586-596... 

The models considered in this section refer to catalytic systems for which the polymerization reaction occurs by primary insertion of the 1-alkene and neither chirality of coordination of the aromatic ligands nor chirality at the... 

H. Tanaka, S. Tokito, Y. Taga, and A. Okada, Novel metal-chelate emitting materials based on polycyclic aromatic ligands for electroluminescent devices, J. Mater. Chem., 8 1999-2003 (1998). 

Figure 13. Transition states for propene insertion into the Zr-isobutyl bond of the racemic-dimethylsilyl-bis-l-indenyl zirconocene with a (RJt) coordination of the aromatic ligand. C2 is the overall symmetry of the metallocene, while re and si is the chirality of coordination of the propene molecule in the transition states of parts a and b, respectively.

Ligand-centred (LC) transitions between bonding and antibonding ligand-centred MOs. These transitions are expected for aromatic ligands with extended n- and it -orbitals. 

In conclusion, structures containing polyiodide anions, with cationic aromatic ligands as counter parts of formulae [(L)(HL+)] (I ) are known to be synthesized by the treatment of the appropriate amide with HI [26-28], In contrast, the complexes with PYOH, in the present case, were formed by the direct reaction of 2-hydroxypyridine with di-iodine in a molar ratio of 2 1 and 1 2. This is a redox reaction, where 2-hydroxy-pyridine firstly is oxidized to pyridinone-2 radical cation. In the case of 2-hydroxy-pyridine however, peroxide structures are not formed like disulphides in the case of PYSH. Polyiodide anions are simultaneously produced in this case This should be a consequence of redox differences between -SH and OH groups and may be proven a useful pathway for the synthesis of polyiodide materials. 

S.3.2.2. Lithium Borates with Aromatic Ligands. A new class of lithium salts was developed... 

S.3.2.3. Lithium Borates with Nonaromatic Ligands. The presence of aromatic ligands in Barthel s salts was believed to be responsible for the high melting points and basicity of the borate anions, which in turn translate into moderate or poor solubilities and ion conductivities as well as low anodic stabilities. To avoid use of these bulky aromatic substituents, Xu and Angell synthesized a series of borate anions that are chelated by various alkyl-based bidentate ligands, which serve as electron-withdrawing moieties by the presence of fluorine or carbonyl functionalities. Table 13 lists the... 

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