Thermal analysis of dithiomalonamide complexes

Abstract

Dithiomaionamide [H2A, CH2(CSNH~):I and 2,2-dimethyldithiomalonamide [H2B, C(CH3)2(CSNH:)2] can act as bidentate ligands and form stable, cationic 1:2 complexes with general formula M2(H2L)2X2 [M=Ni 2+, Pd 2+, Pt2+; X=CI, Br, I; H2L=H2A, H2B] in strong acidic medium. An elaborate thermal study is presented, based on results from elemental analyses and vibrational studies (IR and Raman spectroscopy). The H2A complexes start to decompose by releasing two HX molecules whereafter a stable intermediate M(HA)2 is formed. The H2B complexes degrade in a different way; the metal-sulphur bond is broken and the ligand is expelled as a whole. Influences of the metal ion and of the halogenide eounterions are investigated.

Strain-based design, direct macrocyclization, and metal complexation of thiazole-containing calix[3]pyrrole analogues

“…Given the synthetic availability of furan precursor 6, 14 we investigated direct macrocyclization synthesis of 5 using a Hantzsch-type thiazole formation reaction. 15 To our delight, the condensation reaction between 6 and 2,2-dimethylpropanebis(thioamide) (7) 16 in refluxing ethanol gave calix [1]furan[2]thiazole (5) in 60% yield (Scheme 1), along with a double sized macrocycle, calix[2]furan [4]thiazole, in 16% yield (compound 14 in ESI †). The 1 H NMR spectrum of 5 in CDCl 3 showed time-averaged C 2v molecular symmetry, featuring four singlet signals at 6.78, 5.88, 1.93, and 1.63 ppm assignable to thiazole, furan and two different methyl protons, respectively.…”

Strain-Based Design, Direct Macrocyclization, and Metal Complexation of Thiazole-Containing Calix[3]pyrrole Analogues

“…Given synthetic availability of furan precursor 6, [14] we examined direct macrocyclization synthesis of 5 using a Hantzsch-type thiazole formation reaction. [15] To our delight, condensation reaction between 6 and 2,2-dimethylpropanebis(thioamide) (7) [16] in refluxing ethanol gave calix[1]furan[2]thiazole (5) in 60% yield (Scheme 1), along with a double sized macrocycle, calix[2]furan [4]thiazole in 16% yield (see SI). The 1 H NMR spectrum of 5 in CDCl3 showed time-averaged C2v molecular symmetry, featuring four singlet signals at 6.78, 5.88, 1.93, and 1.63 ppm assignable to thiazole, furan and two different methyl protons, respectively.…”