Thermisches Verhalten und Thermochromie von Übergangsmetallkomplexen pyridylsubstituierter Sulfonamide

Thermal Behavior and Thermochromism of Transition Metal Complexes of Pyridyl Substituted Sulfonamides The thermal behavior of 1,2-complexes of nickel(II), copper(II) and cobalt(II) with pyridyl substituted sulfonamides (N1NHSO₂PhH, N2NHSO₂PhH, N3NHSO₂PhH and N1SO₂NHPhH) is studied between 20° and 600°C by TG, DTG, and DTA and more precisely characterized by identification of volatile decomposition products. In general the thermal decomposition starts by the reaction of one of the ligands with coordinated water or with the water vapor of air. Undecomposed N1NHSO₂PhH and N3NHSO₂PhH pass over to the vapor-phase, in the other cases the elimination is connected with a hydrolytic cleavage of the ligand. The thermal decomposition of Ni(N1NSO₂PhH)₂(NH₃)₂ is initiated by a transamidation. A study of Ni(N1NSO₂PhH)₂ demonstrates the influence of reaction conditions on the course of thermal decomposition. As far as milligram amounts are used, hydrolysis by the water vapor of air is dominating; but sulfur dioxide is eliminated when working in a preperative scale. The thermochromism of Ni(N2NSO₂PhMe)₂(H₂O)₂ goes back to the reversible transition of coordination water to lattice water. This is the first example of isomerism of the Lifschitz-type in the field of neutral chelates.