Amines, donor-acceptor complexes with

Due to its distinctly hydrophobic character, C,5o is also practically insoluble in water. The concentration of a saturated solution is a homeopathic 3 x 10 molT. This value increases upon addition of amines as they may form donor-acceptor complexes with the fullerene. Colloidal solutions with particles measuring 0.22 pm and a concentration of 7 x 10" moll" have been obtained by the aid of ultrasound. Also did the application of complexing host molecules Uke y-cydodextrines lead to a higher solubihty. Surfactants serve to the same purpose. Strictly speaking, however, there are no real solutions in this case, but the fidlerene molecules are located inside of miceUes. 

Eullerene-based donor-acceptor complexes and ion-radical salts with tetrathia-fulvalenes, metalloporphyrins, and cyclic amines as donors 99UK23. 

Blackstock, S. C., J. P. Lorand, and J. K. Kochi. 1987. Charge Transfer Interactions of Amines with Tetrahalomethanes. X-ray Crystal Structures of the Donor-Acceptor Complexes of Quinuclidine and Diazabicyclo-[2.2.2]octane with Carbon Tetrabromide. J. Qrg. Chem. 52,1451. 

The long known132 electron donor-acceptor complexes between tertiary amines and carbon tetrahahdes are simple systems. Thus, l,4-diaza[2,2,2]bicyclooctane (DABCO) or quinuclidine afford solid complexes with carbon tetrabromide142. 

Owing to the presence of the amine and cyanide ligands, known to give rise to specific donor-acceptor interaction with solvents [126-130], an interesting solvatochromic behavior is observed for these species. For complex 1 the spectral changes are dominated by amine interactions with the solvents as shown by the linear correlation of the solvent donor number [131] with the IT band maxima and with the half-wave potential of the ruthenium amine moiety. 

In Sect. 1.3, photoinitiation by means of donor—acceptor complexes was described. In some cases, these complexes may play an important role even without the contribution of light energy. In the presence of aliphatic amines and CCI4, methyl methacrylate is polymerized at temperatures 300 K. In polar solvents (7V,7V-dimethy formamide, dimethylsulphoxide, chloroform), interaction of aliphatic amines as donors with methyl methacrylate as acceptor produces complexes [91] which yield initiating radicals with CC14 [92]... 

Summary Silicon atoms in solid argon react with amines (NR3, R = H, CH3) and phosphine (PH3) to form donor-acceptor complexes, which are stable under matrix conditions. Upon subsequent photochemical excitation, rearrangements take place leading to the corresponding aminosilylenes or to phosphinosilylene (formal insertion products). On further irradiation, additional isomerizations and elimination reactions occur. In matrices containing high concentrations of amines the final products are diaminosilanes. 

I2 with pyridine and quinoline derivatives shows that a reasonably linear correlation exists between log (K equilibrium constant) and pK for donors bearing no orthp-substituents. Sambhi and Khoo have reported their estimates of the magnitude of the contribution of effects other than charge transfer to AH of amine-l2 complexes. The 1 1 and 1 2 adducts of hexamethylenetetramine with I2 have been investigated by X-ray crystallography. Both compounds belong to the class of n-cr donor-acceptor complexes. The I—I distances are 2.830 in the orange 1 1 adduct and 2.791 and 2.771 0.002 A in the red-brown... 

Boron-nitrogen and boron-phosphorous compounds are classical textbook examples of donor-acceptor complexes. The chemical bonds of the Lewis-acid Lewis-base complexes are usually explained in terms of frontier orbital interactions and/or quasiclassical electrostatic attraction in the framework of the Hard and Soft Acid and Base (HSAB) model [73]. We were interested in seeing if the differences between the bond strengths of boron-nitrogen and boron-phosphorous complexes for different boranes, amines and phosphanes can be explained with the EDA method. 

In common with other first-row elements, nitrogen has only four orbitals available for bond formation, and a maximum of four 2c-2e bonds may be formed. However, since formation of three electron-pair bonds completes the octet, N( R)3, and the nitrogen atom then possesses a lone pair of electrons, four 2c-2e bonds can only be formed either (a) by coordination, as in donor-acceptor complexes, e.g., F3B—N(CH3)3, or in amine oxides, e.g. (CH3)3N—6, or (b) by loss of an electron, as in ammonium ions NH, NR 4. This loss of an electron gives a valence-state configuration for nitrogen (as N+) with four unpaired electrons in sp3 hybrid orbitals analogous to that of neutral carbon, while, as noted above, gain of an electron (as in... 

The highest conductivities thus far observed in organic molecules are found among the donor-acceptor complexes. The activation energies for conduction are small, on the order of 0.1 eV ( 2 kcal) or less. Examples are the complexes of aromatic hydrocarbons with iodine and complexes of amines with chloranil or related quinones. The best conductors have a high free-radical content and are usually not of simple stoichiometry. The complex salts of TCNQ ° (I) are the best of the known organic conductors. The... 

The donor-acceptor complexes formed between electron acceptors (such as iodine or tetracyanoethylene) and electron donors (such as aliphatic amines or aromatic hydrocarbons) have, been extensively studied from various points of view -spectroscopic 5 structural and thermodynamic (3). Kinetic investigation has lagged behind, because the reactions are extremely fast and the equilibrium constants small the rate constant of one such reaction had been measured by means of our microwave apparatus (without the recent improvements), at -83 C (U). We have now determined rate constants, in 1-chlorobutane, as solvent for the reactions of zinc tetraphenyl-porphyrin with pyridine and 2-methyl pyridine, which have been well characterised by spectrophotometric methods (5, 6). They are less than the diffusion-controlled value by an order of magnitude. Further investigations are in progress. 

Blackstock, S.C., Lorand, J.P. and Kochi, J.K. (1987) Charge-transfer interactions of amines with tetrahalomethanes. X-ray crystal stmetures of the donor-acceptor complexes of quinucli-dine and diazabicyclo[2.2.2]octane with carbon tetrabromide. J. Org. Chem., 52,1451-1460. 

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