Odd–even effect in melting properties of 12 alkane-α,ω-diamides

Fusion and solid-to-solid transitions of a homologous series of alkane-α,ω-dinitriles

“…However, the zig-zag trend is rather smoothed for the alkanes since their temperatures of fusion increase less sharply on passing from even to odd terms than from odd to even terms. Higher T fus for even terms were already reported for a number of linear alkyl mono-and bifunctional compounds such as n-alkylamines [11], n-alkane-1-ols [11,51], n-alkanoic acids [9,51], alkane-a,x-dithiols [52], alkane-a,x-dicarboxylic acids [8], alkane-a,x-diamines [16], alkane-a,x-diamides [17] and alkane-a,x-diols [53]. However, an opposite alternation has been described for alkane-1-thiols [6,11] and dialkyl-oxybenzoquinones [54].…”

“…Packing effects have been advanced to explain the alternation [13][14][15][16][17]. However, solid-state structural studies on alkyldinitriles have been hampered by the fact they are liquids or semisolids at ambient temperature.…”

“…The odd and even terms of homologous series of variously terminally substituted linear alkyl compounds are known to behave differently with respect to both their fusion and sublimation thermodynamic properties and other physical and chemical quantities, such as density, molar volume, solubility in various solvents [5][6][7][8][9][10][11]. Correlations with crystal structures and packing patterns have often been invoked for this carbon-number-based alternation [12][13][14][15][16][17].…”

“…the temperatures and enthalpies of solidto-solid and fusion transitions of 11 linear alkyldinitriles as a part of our recent investigations of homologous series of model compounds [16][17][18][19][20][21][22][23][24][25][26][27]. Comparison was made with the literature values for temperatures, and enthalpies and entropies of fusion of both isoelectronic linear alkanes H 3 C-(CH 2 ) n -CH 3 [5,11] and alkane-a,x-diamines H 2 N-(CH 2 ) n -NH 2 [16].…”

Thermochemical studies on five N-thenoylthiocarbamic-O-n-alkylesters

“…These differing ''odd-even'' features of phase transition properties are found in other classes of compounds, e.g. in alkanes [25], 4-n-alkylbenzoic acids [26], alkane-a,x-diamines [27], alkane-a,x-dioles [28], and in alkane-a,x-diamides [29].…”