The constitution of a number of 2-(iminomethyl)benzenethiols and 2- (iminomethyl)-4-nitrobenzene-thiols has been studied by 1H N.M.R. spectroscopy. A zwitterionic imminium structure is suggested for all the compounds studied except for the 4'-methoxyphenylimine derivative which exists in the thiol form.

The synthesis of a number of cobalt(11) and cobalt(111) complexes of bi-and tetra-dentate N-substituted o-mercaptobenzaldimines is reported. The Co" bidentate complexes are spin-free and the tetradentate are spin-paired. 2,2'-[Ethylenebis(nitrilomethylidyne)]bis(benzenethiolato-S,N)cobalt(11) (Co-(mben)) does not behave as an oxygen carrier at room temperature, in contradistinction to Co(sa1en). The complex is easily oxidized in the presence of water to [C~(mben)(H~O)~]' ions. A synthetic route to the complexes through the aldehydato complex C~( m b )~ is described which avoids condensation of the aldimines to cyclic nonanes.

The X-band e.s.r, spectrum of a copper(n) Schiff-base complex, 2,2'-[ethylenebis(nitrilomethylidyne)]-bis(benzenethio1ato-S,N)copper(11) (Cuimben)), has been determined in frozen toluene-chloroform solutions. The complicated lineshape has been simulated by a computer program incorporating symmetry around the copper lower than axial, together with a nitrogen hyperfine pattern calculated for two cis nitrogen atoms. The e m . parameters are compared with those obtained for two other thio Schiff-base chelates and with those for the salicylaldimine analogue, Cu(sa1en). Metal-ligand covalency parameters estimated from the e.s.r. parameters are discussed briefly.

Die Reaktion zwischen dem Aldehyd (I) und prim. Aminen (II) führt zur Gleichgewichtsmischung von‐(III) und (IV).

Der Cu‐Komplex (Ia) wird dargestellt durch Reaktion von Cu(II)‐acetat mit einer Mischung von Mercaptobenzaldehyd und Ethylendiamin in Ethanol.