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The syntheses of alkyl and aryl-substituted tetrakis(amino)phenylphosphonium compounds of type (RNH)4-n (C6H5)nPX, where R = n-C3H7 (1), i-C4H9 (2), n-C4H9 (3), s-C4H9 (4), n-C6H13 (5), c-C6H11 (6), C6H5CH2 (7) and C6H5 (8), and where X = Br, and (C6H5)4B, are described. These compounds have been characterized by elemental analysis, melting point and 1H and 31P NMR spectroscopy. Solubility characteristics in water and organic solvents are given for several derivatives within each series. It has been found that as the number of phenyl substituents on the phosphorus increases, so does the solubility in most solvents investigated. The mild conditions used to synthesize a tetraphenylborate derivative from the corresponding phosphonium bromide indicates the relative ease with which these phosphonium compounds undergo metathesis reactions. Hydrolysis reactions undergone by several partially substituted intermediates, as well as unreacted starting materials have been found to cause lower reaction yields...

The synthesis of tetrakis(alkyl/arylamino)phosphonium compounds of type (RNH)4PX, where R = n-C3H7 (1), i-C3H7 (2), n-C4H9 (3), s-C4H9 (4), n-C5H11 (5), n-C6H13 (6), c-C6H11 (7), n-C7H15 (8), C6H5CH2 (9) and C6H5 (10), and where X = Cl, Br, I and ClO4, is described. These compounds have been characterized by elemental analysis, melting point and 1H and 31P NMR spectroscopy. Solubility characteristics in water and organic solvents are given for the chlorides, which have been found in general less soluble than the corresponding perchlorates. Metathesis reactions of the (RNH)4PCl compounds are shown to proceed with relative ease and have provided an adequate method for the conversion of the chlorides to bromides, iodides and perchlorates. Hydrolysis reactions for compounds 3, 9 and 10 have been studied and compared. Their relative stability toward base hydrolysis is demonstrated by the conditions used and the isolated intermediates identified, consistent with the postulated base hydrolysis scheme. N...

A general discussion of electronegativity and electronegativity equalization is presented as background for the concept of charge capacity; the latter is the ability of an atom to absorb or yield electronic charge. We have discussed charge capacity in relation to a variety of atomic and molecular properties, e.g. atomic polarizabilities and outer shell properties, electron affinities, dipole moments, electronic density distributions, dissociation energies, electrostatic potentials, spectroscopic measurements, acidities, etc. Significant increases in charge capacity and decreases in electronegativity in going from the first to subsequent rows of the periodic table are important in explaining (especially for columns IV–VII) the discontinuities in many physical and chemical properties that occur between these rows. It is demonstrated that both intrinsic electronegativities and charge capacities must be considered in order to understand the redistribution that occurs when atoms interact to form molecules. We discuss many seemingly anomalous observations of chemical behavior that are explained quite readily when both of these factors are taken into account.

The crystal structure of trans-bis(8-aminoquinoline)aquazinc(II) tetrachlorozincate(II), [Zn(C9H8)2H2O, ZnCl4], monoclinic C2/c, a = 11.234, b = 10.8527, c = 19.025 A, β = 108.43°, Z = 4, has been determined with X-ray (MoKα) diffractometer data. The structure was solved by direct methods and refined with full-matrix least-squares to R = 0.041. The cation and anion lie on a crystallographic dyad. The anion has the expected tetrahedral configuration. The structure of the cation is roughly halfway between the limiting trigonal bipyramid and square pyramid five-coordinate geometries. The structure is rationalized on the basis of the bite of the 8-aminoquinoline, and the electronegativities of the two nitrogen atoms and water oxygen atom.

Mathematical models of mimicry are attempts to simplify the complexity of real mimetic situations with only a few parameters. As such, they cannot be expected to mirror reality accurately. Nevertheless, they have stimulated much further thought, the collection of further field data, experimental testing in the laboratory, and further elaboration of the mathematical models. The succession of models has seen increasing preciseness of definition, increased scope of applicability, and increased accuracy in the depiction of mimetic situations. Their prediction of ecological and evolutionary relationships has been quite valuable. Even when mathematical models have been shown to be deficient, they have proven to have heuristic value in stimulating thought and discussion. The quarter of a century since they were first proposed has seen no diminution in the vigor of the work on these models, and we can expect this situation to continue.

The apparent conflict between the empirical HSAB rule and Pauling's Electronegativity Equation is examined and discussed in terms of more recent (Mulliken-Jaffe) electronegativity theory. It is concluded that no basic conflict exists but that Pauling's concept of “ionic resonance energy” neglects the variation in bond length from molecule to molecule, an error that is not serious in calculating electronegativities from bond energies but which is emphasized when applied to the prediction of enthalpies of HSAB reactions.

Hard and soft acid-base interactions are investigated from the point of view of various factors contributing to the total bond energy. A method of estimating the total energy as the sum of three contributing energies is proposed. The three energies are the Madelung energy, derived from a coulombic model; the covalent energy, related to Pauling's geometric mean but allowing for loss of overlap with increasing ionicity; the electronegativity energy, the energy resulting from transfer of electron density from a less electronegative element to a more electronegative element. The latter is estimated from Mulliken-Jaffe electronegativies. The results correlate quite well (r = 0·98) with experimental enthalpies of atomization. It is concluded that hard-hard interactions contain considerable covalent bonding as well as Madelung energies. Fajans' rules and covalency, the “anomalous” bond energies of sodium and magnesium compounds, and the validity of the principle of electronegativity equalization are discussed.

The ecology and life history of Desmognathus ochrophaeus inhabiting wet rock faces at high elevations near Highlands, North Carolina, were studied. Comparisons were made with rock-face populations in Great Smoky Mountains National Park and with woodland populations at Rabun Bald, Scaly Mountain, and Blue Valley in the Blue Ridge Mountains. The reproductive cycle in rock-face populations is annual; spawning occurs mostly in July and August, and females begin to emerge from brooding as early as late August. The new spermatogenic cycle begins in May and June. Animals on rock faces average 40-45 cm in movements between successive captures and appear to have a limited range. Animals displaced to the base of the rock face and higher on the rock face can return to their home range. Population density is high (up to 25 individuals/M2), diurnal activity is nearly as high as nocturnal activity (correlated with subdued body colors), and at least a moderate level of activity occurs during warm winter periods. Animals mature at 2 years of age as in woodland populations, but at a smaller size, and grow more slowly thereafter. Small body size is not due to paucity of food on the rock faces. The high population densities on the wet rock faces indicate that they are highly favorable habitats for D. ochrophaeus. Differences between rock-face and forest-floor populations are attributable to modified selective pressures in the two different ecological settings. Variation among rock-face populations is attributed to the intensity of selection for small body size and cryptic coloration, the size of the rock face, and variation among forestfloor populations from which they were derived. Since rock-face populations are linked genetically to surrounding forest-floor populations of D. ochrophaeus, they cannot be considered examples of taxonomic variation, but rather of ecotypic variation.

The effect of size upon the strength of hard and soft acid-base interactions is examined and it is concluded that hard-hard interactions are especially stabilized by small size that favors enhanced Madelung and covalent bonding energies. For the ionic species studied, the soft-soft interaction appears to be a negative one, i.e. it is imposed by the tendency of hard species to associate with each other. The homopolar bond energy may be related quite accurately (r = 0·975) to the bond length as EH = 132·5−37·1 r (EH = energy in kcal/mole; e = bond length in Angstroms). Consideration of lone pair repulsions allows even better prediction of homopolar bond energy as a function of bond length.

Atomic charges have been calculated by a simple model involving partition of total molecular bonding energy into “ionic” and “covalent” components. These charges agree well with those obtained by Politzer's electron-count method of assigning charge but not with charges obtained by populational analysis. It is argued that Politzer's definition of charge is closer to the intuitive use of the word “charge” by chemists than is that based on populational analysis. Further examples of the importance of consideration of valence state electronegativities and charge capacities are discussed.

Over one hundred years ago, Bates (1862) proposed that palatable prey should gain an advantage if they resembled and were mistaken for less palatable prey by predators. Seventeen years later, Muller (1889) proposed that a mutual advantage accrued to aposematic prey that converged in pattern to reduce predator error. Several recent workers (Huheey, 1961; Brower and Brower, 1964; Brower et al., 1970; Pough et al., 1973) have discussed the idea, first suggested by Dixey (1908) and clarified by Darlington (1938) and Fisher (1958), that there is no sharp dividing line between classical Batesian mimicry in which an innocuous mimic resembles a noxious model, and Miillerian mimicry in which two or more noxious models resemble each other. All cases in which two models, M1 and M2, do not have identical noxiousness will lie on a spectrum between the two limiting extremes of classical Batesian mimicry (noxiousness of M2 = 0) and classical Miillerian mimicry (noxiousness of M2 = noxiousness of M1). There has been some discussion of the evolution of Batesian and Miillerian mimicry in terms of this spectrum, but little of a quantitative nature has been attempted. Although the idea of a continuity of possibilities from Batesian mimicry at one extreme to Miillerian mimicry at the other is not a radical concept, surprisingly it does lead to several seeming contradictions. There are a number of tenets of mimicry theory that have been developed over the years (Carpenter, 1937; Sheppard, 1958; Wickler, 1968). In quite a large number of cases, the tenets for Batesian mimicry are diametrically opposed to those for Millerian mimicry (see Fisher (1958, p. 166) for, a concise and vivid description). The existence of a Batesian-Miullerian spectrum suggests that the supposed differences between the two be re-examined. Since the development of a mathematical model to describe Batesian mimicry (Huheey, 1964) has led to considerable work and interesting conclusions (Brower et al., 1970; Pough et al., 1973; Estabrook and Jesperson, 1975; Huheey, in ms.; Bobisud and Potratz, 1976; S. Arnold, Univ. of Chicago, pers. comm.), a similar study of Miillerian mimicry should prove useful.

A comparison is made between the electronegativities of ``quark atoms'' as predicted by a recent article, and those suggested by traditional chemical methods. It is shown that the neglect of valence-state considerations for the ionization energies and electron affinities produces serious errors in calculating electronegativities by the Mulliken method. As analyses of the values for ``normal atoms'' show such disparities, it is likely that the new numbers are in error.

Pseudotriton ruber and P. montanus possess a proteinaceous skin toxin of mol. wt greater than 200,000. In terms of toxicity and amount present in the skin, pseudotritontoxin is comparable to tetrodotoxin, the other toxin in North American salamanders. The pharmacological action of pseudotritontoxin on mice includes the distinctive symptoms of hyperextension of hind legs and lower back, extreme irritability, severe hypothermia, quiescence, prolonged debility, and coma, with time-to-death of an ld 50 dosage from 12 to 48 hr. Larger doses cause an increase in severity symptoms with convulsions and death occurring at 1 hr or more. In contrast, lethal doses in young chickens cause convulsions and death in a few minutes. The concentration of toxin is greatest in the back skin, being five times that of belly skin, 35 times that of the gut, 18 times that of the liver, and 17 times that of the ovaries. Pseudotritontoxin is the first toxin to be identified in the Plethodontidae, the largest family of salamanders with over 200 known species. It is unusual in being one of the few amphibian poisons of high mol. wt. It also necessitates a re-examination of the mimetic relationships among the red eft, Notophthalmus viridescens , the red salamander, P. ruber , the midland mud salamander, P. montanus diastictus , and the spring salamander, Gyrinophilus porphyriticus . The best interpretation of this mimicry seems to be that of a Mullerian complex with a spectrum of unpalatability among the species.

The origin of right-handedness as the predominant chirality in humans seems to be related to the tendency of human (and presumably prehuman) mothers to hold infants on the left side. The latter practice has previously been ascribed to imprinting and the soothing sound of the mother's heartbeat on the infant. Given the practice of holding the child in this manner, dextral mothers will be more skillful at manipulation of objects and selectively favored.

The purpose of this review is to provide a current analysis of warning coloration and mimicry to accompany the other discussions in this volume of the chemical ecology of insects. Recent literature in this area includes a chapter devoted principally to the chemical aspects of mimetic and aposematic associations (Eisner, 1970) and two excellent chapters on mimicry provided by Ford (1975) in his book on ecological genetics. The only recent book on mimicry available in English (Wickler, 1968) provides an introduction to many aspects of the subject but sometimes goes rather far afield. Pasteur (1972) has written a useful little book, but it is not readily available in this country. Rettenmeyer (1970) and Turner (1977) have written thorough reviews of insect mimicry and butterfly mimicry, respectively, and the reader is referred to those articles for the earlier discussions. The present review attempts to place mimicry in the ecological and evolutionary context of the chemical ecology of insects. Most of the examples discussed in this chapter will be from that group, but since the primary purpose is to develop the principles, selective forces, limitations, and results of mimicry, examples from other animals will also be included where they provide relevant insights. The extremely interesting topic of plant mimicry has been completely omitted (Wiens, 1978). The literature is reviewed through the first half of 1983, but some references have reluctantly been omitted because of space considerations.

The relation between 119Sn Mossbauer shifts and atomic parameters such as Mulliken valence state electronegativities is discussed. It is concluded that group electronegativities, per se, are not directly related to isomer shifts and the presence or absence of pi bonding must be considered.