Synthesis and Characterization of Copper(II) Complexes of a 14‐Membered cis‐N₂S₂ Dibenzo Macrocycle and of Its Bis‐acetato and Bis(methylpyridyl) Derivatives

Abstract

The synthesis and characterization of seven copper coordina-hibit very similar overall structures in the cationic part. The tion compounds with the 14-membered macrocyclic cis-NzS2 macrocyclic ring of the ligand is folded along an N...S axis, dibenzo ligand 6,?,13,14,15,16,17,18-octahydrodibenzo[e,m]-the octahedral geometry is strongly Jahn-Teller distorted, L3.The structural, spectral, EPR, and electrochemical properties of these compounds will be compared with complexes described as possible models of N2S2 coordination environments at the active sites of "blue" copper(I1) proteins [*]. Results and DiscussionThe hexadentate ligands H2L2 and L3 were prepared in moderate yields by one-step reactions from the preformed macrocycle L1 and a-bromoacetic acid (H2L2) or 2-[@-tolylsulfonyl)methyl]pyridine (L3). According to the IR spectrum H2L2 exists in a zwitterionic state: one of the tertiary amine functions is protonated and one of the carboxyl groups deprotonated. The other carboxyl group forms a strong intermolecular hydrogen bond to the carboxylate group of a neighboring ligand molecule as is shown by the high background infrared absorption in the range from 1800 to 600 cm-' with a maximum at 1400The preparation of the copper(I1) complexes 1 and 3-7 was straightforward by using the appropriate inorganic components. All the complexes are stable in air and readily soluble in water. The copper(1) compound [CuL'IBr . MeCN (2) is air-sensitive.

New FeII and CuII Complexes Bearing Azathia Macrocycles – Catalyst Precursors for Mild Peroxidative Oxidation of Cyclohexane and 1‐Phenylethanol

“…The packing pattern of 2 is dominated by intermolecular O2 ··· O2 i [3.034(2) Å, (i) 1 – x , 1 – y , 1 – z ] and O5 ··· O5 ii [2.977(3) Å, (ii) 1 – x , 1 – y , – z ] short contacts between adjacent triflate moieties, giving rise to houndstooth‐like supramolecular 1D chains (Figure 2). In general, the bonding parameters in 2 (Table 1) are comparable to those encountered in Cu II complexes with related N 2 S 2 ligands 8…”

“…To prepare the new iron and copper complexes with macrocyclic azathia ligands, we have selected the 14‐membered N 2 S 2 macrocycles L 1 and L 2 (Scheme ), as their application in coordination chemistry is still limited 3,6–8. For comparative purposes, we have also synthesized a new nine‐membered NS 2 macrocycle L 3 bearing a pendant 2‐methylpyridyl arm, which can also act as a tetradentate N 2 S 2 ‐donor ligand.…”

“…Aiming at studying the coordination chemistry of Fe II and Cu II with azathia macrocycles, we have concentrated on the 14‐membered N 2 S 2 macrocycle [6] L 1 and its recently reported7 N , N ′‐dimethyl derivative L 2 (Scheme ) as their use in the synthesis of iron and copper complexes remains poorly explored 3,8. Another aim of this work was the functionalization of a nine‐membered NS 2 macrocycle (7‐aza‐1,4‐dithiacyclononane) with a pendant pyridyl arm (2‐methylpyridyl) to obtain a new potentially tetradentate N 2 S 2 ‐donor ligand L 3 , and to probe its complexation with Fe II and Cu II .…”

Copper complexes as a source of redox active MRI contrast agents

“…Although both alcohol groups are found above the plane of the ligand and are protonated, only one of the hydroxyl groups coordinates. The structures of the corresponding ethanol, acetate thioether adducts remain unclear at this time but we would predict that they are also five coordinate in the solid state (Funkemeier & Mattes 1993;Bentfeld et al 1995;Mattes et al 2004). …”

Liganden mit N/S-Donorsets in der Münzmetallchemie: Modellkomplexe für Methanobactin und multinukleare, lumineszierende Pyrazolat-Komplexe

“…[42] I. Blauen Kupferproteinen verwendet werden. [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] Einige von ihnen sind mit dem Koordinationsmotiv des Methanobactins vergleichbar. Pyridin-Substituenten können hierbei als struktureller Ersatz der Oxazolon-Substituenten betrachtet werden.…”