Untitled

Abstract

Pyridyl bis(N(4)-substituted thiosemicarbazones), in which the substituents replacing the NH 2 group on the thiosemicarbazone moieties are piperidyl, H 2 Plpip; hexamethyleneiminyl, H 2 Plhexim; diethylamino, H 2 Pl4DE; and dipropylamino, H 2 Pl4DP, have been synthesized. These bis(thiosemicarbazones) and their nickel(II) complexes have been characterized with IR, electronic, mass, and 1 H and 13 C NMR spectra. Crystal structures have been solved for H 2 Plpip and all four nickel(II) complexes. H 2 Plpip does not possess hydrogen bonding between the thiosemicarbazone moieties, but is in the Z isomeric form with intramolecular hydrogen bonding from both thiosemicarbazone moieties to pyridine nitrogen atoms. The nickel(II) complexes possess square-planar N 2 S 2 (i. e., imine nitrogen and thiolato sulfur atoms) centers and the two pyridine ring nitrogen atoms are not coordinated.

Bonding and structure trends of thiosemicarbazone derivatives of metals—An overview

“…The common coordination modes are XXI and XXII depending on the participation of the central ring connecting the two arms [33][34][35].…”

“…A series of bis-thiosemicarbazone complexes, [NiL] 163-174 are shown in Chart 22 [33,217,[227][228][229][230][231][232][233]. Bis-ligands are dinegative after deprotonation of the -N 2 H group, and bind in a variety of modes.…”

Structural and Spectral Studies of Palladium (II) Complexes of Pyridil bis{3-Piperidyl-, bis{Hexamethyleneiminyl-, bis{N(4)-Diethyl- and bis{N(4)-Dipropylthiosemicarbazone}

“…1), as was found for pyridil bis{3-piperidylthiosemicarbazone), HoPlpip [4]. It should be noted that intramolecular hydrogen bonding be tween the thiosemicarbazone moieties does occur for FbPgpip, 1-phenylglyoxal Z?/s(3-piperidylthiosemicarbazone} [11].…”

“…Since ^«(thiosemicarbazones) are no more effec tive than heterocyclic N(4)-substituted thiosemicar bazones [3], we have turned to the synthesis and characterization of pyridil ^«(thiosemicarbazones) and their metal complexes, thereby combining the two functions. The spectral data and crystal struc tures of pyridil bis {3-piperidylthiosemicarbazone} and four nickel(II) complexes of pyridil b«(thiosemicarbazones) have recently been reported [4]. A similar report on the copper(II) complexes has been communicated [5], and here we present a study of the palladium(II) complexes, which includes the crystal structures of pyridil fr«(3-hexamethyleneiminylthiosemicarbazone), HbPlhexim, and two of its palladium(II) complexes.…”

“…Colors, partial elemental analyses of palladium(II) complexes of pyridil &/s(thiosemicarbazones). The method of preparation of the pyridil £>«{thio semicarbazones} was presented in an earlier communica tion [4], The palladium(II) complexes were prepared by boiling a pyridil bis(thiosemicarbazone) under reflux with potassium tetrachloropalladate(II) in a 1:1 molar ratio in 96% EtOH for 4 -5 h. The solutions were cooled, filtered and washed with i-PrOH. The yields of complexes ranged from a low of 65.0% for [Pd(Plhexim)]H20 to a high of 90.9% for [Pd2(P14DP)Cl2.…”