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Quantitative Structure-Activity Relationships (QSARs) are derived to predict oral toxicity data of aliphatic amines and anilines for rats. LD,,-values from the RTECS data base are correlated to l-octanol/water partition coefficient (logPo,), fragment-values and electronic properties. Toxicity data of aliphatic monoamines are sufficiently described by a bilinear logPo,-dependent equation, consideration of polyamines requires a fragment-descriptor reflecting the polyfunctionality .-. Toxicity data of anilines are best predicted by a combination of electronic, steric and hydrophobic parameters.As recently demonstrated for hydroxy-compounds [ 121, unsaturated and aromatic compounds fail to fit the corresponding logPo,-dependent model of saturated aliphatic compounds [5]. Predictive power of logPo, is much less for phenols than for aliphatic alcohols [ 121. Further descriptors are required due to varying modes of action.In this study, aliphatic and aromatic amino-compounds are investigated in order to show whether there also is a difference in the predictive power of logP,, for aliphatic amines and anilines .The validity of the developed models is compared with known QSARs.2 Data and Methods Abbreviations and Symbols: QSAR, LD50,

The refined 1H NMR method (AUS concept, CCl4) provided association constants K and approximate complex shifts IK for complexes of nitroaromatics A with aromatic hydrocarbons D. 5-Nitrofurfural (1) and benzene (B) or toluene (T) form syn-1B or syn-1T, respectively; a proton dependence of K indicates about 10% anti complexes. The dimer T2 of T additionally yields some 1T2 since IK values are 29-34% higher than for 1B. With naphthalene (N) or phenanthrene all protons of 1 provide the same K. Picrylacetone (2) and B form 2B and at least one 2BB adduct; published parameters of 2B and 2BB are inconsistent. 2 and N or M (1,3,5-trimethylbenzene) form only 1:1 complexes. All results are in accord with CH2COMe standing perpendicular to picryl. 2,4-Dinitrophenylacetone (3) in a rather flat conformation coordinates with a single stacking N centred over C-6; 3 yields two isomeric stacking complexes 3B and at least one edge-on 3B complex. 2-Chloro-5-nitropyridine (5) forms stacking complexes under repulsion of D by the ring N. In contrast to 1 and 4-nitrobenzaldehyde (6) 1,4-dinitrobenzene (7) and T form only a 1:1 complex that is stabilized by dipole-dipole attraction. Equal and unequal shielding of proton pairs (ortho or meta) in complexes of type 6B is discussed.

The complexation equilibria (solvent CCl4) of fervenulin (F) with benzene (B), naphthalene (N), phenanthrene (P), and fluoranthene (FA) have been investigated (1H‐NMR relative shifts, external reference, AUS correction). The (approximate) complexation shifts Icpt/K indicate a face‐to‐face topology of the complexes that can reasonably be explained by dispersion and Coulomb forces. The increase in the formation constants K from 0.178 (F‐B) to 3.41 l/mol (F‐FA) can be correlated with the size of the contact interfaces.