We have synthesized and characterized five copper(I) complexes with unsymmetrically substituted thiourea ligands. These include two coordination polymers, [Cu(S tu NH)Br] n and [Cu(S tu(Py) NH)Br] n , two dinuclear complexes, [Cu 2 (S tu NH) 4 Br 2 ] and [Cu 2 (S tu(Py) NH) 2 Br 2 (MeCN) 2 ], and one hexanuclear complex, [Cu 6 (S tu N) 6 ]. The Cu atoms of the coordination polymers are connected through alternating thione and bromide bridges and the dimeric structures through thione bridges. The thionebridged structures show similarities with the biologically highly [a] 1266 Scheme 2. Reaction scheme leading to the copper(I) complexes C1-C5. The ratios in parentheses refer to ligand/metal ratio.
Cu–S heteroadamantanes are of great interest owing to their relevance to bioproteins. New copper(I) thiolate compounds with additional N‐donor functions from phenanthroline ligands have been synthesised. These complexes feature heteroadamantane cage structures with minor deviations in their construction and, therefore, a strong structural relationship. Furthermore, a decanuclear copper–sulfur cluster complex was isolated and shows known structural motifs arranged in a new fashion. Metallothioneins are natural counterparts to these complexes due to their thiolate‐rich and polynuclear d10 character. In addition to the structural characterisation, theoretical studies with a triple‐zeta basis set have been performed to further understand the building patterns of the reported complexes and their relevance to copper‐rich metalloproteins. This includes a Wiberg bond analysis and a full orbital analysis of selected heteroadamantanes to highlight the bonding interactions that connect the copper–sulfur skeletons.
The possibility to form hydrogen bonds with different motifs is an interesting aspect of the chemistry of thioureas especially regarding catalysis. We present nine new thioureas with different unsymmetric substitution patterns involving aromatic and aliphatic substituents including the structural characterization of four of them. Herein, three different hydrogen bond patterns could be realized. Moreover, DFT calculations were performed to investigate the strength of the hydrogen * Prof. Dr. S. Herres-Pawlis E-Mail: sonja.herres-pawlis@ac.rwth-aachen.de [a] 660 bonds. Hereby, we show that we can selectively address different hydrogen bonding motifs by the choice of substituents. This enables a correlation of the molecular structure and the bonding motifs. Additionally, by natural resonance theory, we show that the contribution of the thiolate resonance form dominates the electronic structure, which is important for coordination chemistry.
The electrochemical synthesis is an underestimated synthesis protocol, which can lead to unexpected results. We obtained an unusual CuI complex salt with a pentanuclear anion and a heptanuclear cation. The anion [Cu5(StBu)6]– features a trigonal prism coordination motif with a twisted arrangement. The cation [Cu7(StBu)6(bipy)3]+ is structurally almost identical to the anion and shares therefore basic building principles. These Cu–S skeletons with additional N donor functions in the cation have relevance to biological copper proteins. Besides structural discussion and analysis, a theoretical study was performed to determine stabilizing effects. This is accomplished by means of DFT with a triple‐zeta basis set and the TPSSh functional in order to highlight bonding interactions and to understand d10–d10 interactions, which are assigned a major stabilizing part. This is realized through Wiberg bond analysis and frontier orbital analysis of both ions.
The reaction of Cu(I) bisguanidine complexes with nitric oxide and the formation of intermediate species were monitored via UV-vis spectroscopy at low temperature, with the occurrence of characteristic absorption bands. The origin of the emerging species and their character were substantiated by electron paramagnetic resonance (EPR) measurements and density functional theory (DFT) studies showing a delocalized {CuNO} 11 radical species. Furthermore, this system was transferred to the SuperFocus mixer setup, which allows rapid mixing and the determination of decay constants at ambient temperatures of the thermally sensitive species. However, these experiments demonstrated the limits of these systems, such as the NO saturation in organic solvents and a preferably precise temperature control within the SuperFocus mixer, which should be addressed in the future.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.