Four isomers of 3,5-dibutyl-1H-1,2,4-triazole (3,5-R2tzH, R = butyl (nBu), isobutyl (iBu), secondary butyl (sBu), and tertiary butyl (tBu)) have been synthesized by condensation of the corresponding organic acids and hydrazine, followed by a deamination reaction. Their binary silver complexes have been prepared and structurally characterized by X-ray diffraction. [Ag(3,5-nBu2tz)]n and [Ag(3,5-iBu2tz)]n exhibit 3D structures of cds and dia topologies, respectively, while [Ag(3,5-sBu2tz)]n displays a 2D sql net and [Ag(3,5-tBu2tz)]4 is a 0D tetranuclear complex. Having the same empirical formula, these four binary silver triazolates are true isomers, differing in their linkage and triazole coordination modes. This work represents an interesting case in which ligand isomerism is manifested in the structures of the corresponding metal complexes.

synthesis of urea contributed greatly to the theory of isomerism, as the empirical chemical formulas for urea and ammonium cyanate are identical (see Wöhler The history of chemistry represents a time span from ancient history to the present. By 1000 BC, civilizations used technologies that would eventually form the basis of the various branches of chemistry. Examples include the discovery of fire, extracting metals from ores, making pottery and glazes, fermenting beer and wine, extracting chemicals from plants for medicine and perfume, rendering fat i Avogadro's hypothesis began to gain broad appeal among chemists only after his compatriot and fellow scientist Stanislao Cannizzaro demonstrated its value in 1858, two years after Avogadro's death. Cannizzaro's chemical interests had originally centered on natural products and on reactions of aromatic compounds; in 1853 he discovered that when benzaldehyde is treated with concentrated base, both benzoic acid and benzyl alcohol are produced—a phenomenon known today as the Cannizzaro reaction. In his 1858 pamphlet, Cannizzaro showed that a complete return to the ideas of Avogadro could be used to construct a consistent and robust theoretical structure that fit nearly all of the available empirical evidence. For instance, he pointed to evidence that suggested that not all elementary gases consist of two atoms per molecule—some were monatomic, most were diatomic, and a few were even more complex. Another point of contention had been the formulas for compounds of the alkali metals (such as sodium) and the alkaline earth metals (such as calcium), which, in view of their striking chemical analogies, most chemists had wanted to assign to the same formula type. Cannizzaro argued that placing these metals in different categories had the beneficial result of eliminating certain anomalies when using their physical properties to deduce atomic weights. Unfortunately, Cannizzaro's pamphlet was published initially only in Italian and had little immediate impact. The real breakthrough came with an international chemical congress held in the German town of Karlsruhe in September…

(optical isomerism ); or (2) both chemical and physical properties may be different when the configuration is determined by the disposition of the atoms or