Acetonitrile ligand

Table 4 shows the NMR coalescence temperatures for this process for a number of ligands. In addition to this data it was shown that the exchange rates for the ligands acetonitrile, dimethylsulfoxide, anddiphenyl-... 

Reinhoudt et al. [174] reported the self-assembly of an AB2 type of monomer 83 with two Pd centers. Labile coordinating ligand, acetonitrile, when removed by heating from a solution of nitromethane in vacuo initiated an intramolecular coordination of benzylnitrile group with the tridentate Pd-centers leading to a hyperbranched structure. Coordination of the benzylnitrile group was moni-... 

The complexes [lr(COD)(NCMe)(PR3)]BF4 (PR3 = P Pr3, PMe3), which are closely related to Crabtree s catalyst, also contain mixed ligands, very basic phosphines, P Pr3 or PMe3, and a nitrogen donor ligand, acetonitrile. These mixed-ligand pair combinations have been shown to be very useful for spectroscopic observations and have provided detailed information on the mechanism of reactions performed by those complexes [9, 10]. 

The work of Hyatt on cyclotriveratrylene—derived octopus molecules contrasts with this. Of course, these species have the advantage of ligand directionality absent in the benzene-derived octopus molecules. Except for the shortest-armed of the species (i.e., n = 1), all of the complexing agents (i.e., n = 2—4) were capable of complexing alkali metal cations. Synthesis of these species was accomplished as indicated below in Eq. (7.7). These variations of the original octopus molecules were also shown to catalyze the reaction between benzyl chloride and potassium acetate in acetonitrile solution and to effect the Wittig reaction between benzaldehyde and benzyltriphenylphos-phonium chloride. 

Apart from TiO and the lower halides already mentioned, the chemistry of these metals in oxidation states lower than 3 is not well established. Addition compounds of the type [TiCl2L2] can be formed with difficulty with ligands such as dimethylformamide and acetonitrile, but their magnetic properties suggest that they also are polymeric with appreciable metal-metal bonding. However, the electronic spectra of Ti in TiCl2/AlCl3 melts and also of Ti incorporated in NaCl crystals (prepared by... 

Combination of nickel bromide (or nickel acetylacetonate) and A. A -dibutylnorephcdrinc catalyzed the enantioselective conjugate addition of dialkylzincs to a./Tunsaturated ketones to afford optically active //-substituted ketones in up to ca. 50% ee53. Use of the nickel(II) bipyridyl-chiral ligand complex in acetonitrile/toluenc as an in situ prepared catalyst system afforded the //-substituted ketones 2, from aryl-substituted enones 1, in up to 90% ee54. 

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... 

The free ligands were obtained by visible photolysis in acetonitrile and were characterized by elemental analyses and H- and 13C-NMR spectroscopies. Low-temperature reduction in ESR tubes also provided the green Fe1 19e complexes which gave the characteristic 3g values typical of the rhombic distortion of Fe1 [77],... 

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