Reactions of dichloro[2-(dimethylaminomethyl)phenyl-C1,N ]gold(III), [Au(damp-C1,N )Cl2], with heterocyclic thiols. Evidence for Au–N bond cleavage and protonation of the dimethylamino group

Abstract

Dichloro[2-(dimethylaminomethyl)phenyl-C 1 ,N]gold(), [Au(damp-C 1 ,N)Cl 2 ], reacts with 2-mercapto-1,3thiazoline (HSthiaz), 2-mercaptopyridine (HSpy), sodium 1-methylmercaptotetrazolate (NaSmetetraz), 4-methyl-3-mercapto-1,2,4-triazole (HSmetriaz) or 6-mercaptopurine (HSpur) under cleavage of the Au᎐N bond and protonation of the dimethylamino group. Compounds of general formulae [Au(Hdamp-C 1 )Cl(HL) 2 ] 2ϩ (HL = HSthiaz or HSpy), [Au(Hdamp-C 1 )Cl(L)] (L = Spur Ϫ ) or [Au(Hdamp-C 1 )(L) 3 ] (L = Smetetraz Ϫ ) have been isolated and characterized. The reaction with HSmetriaz leads to a rapid reduction of the metal and the formation of the gold() complex [Au(HSmetriaz) 2 ] ϩ . The crystal structures of [Au(Hdamp-C 1 )Cl(HSthiaz) 2 ]Cl 2 ؒMe 2 CO, [Au(Hdamp-C 1 )Cl(HSpy) 2 ]ؒH 2 O, [Au(Hdamp-C 1 )(Smetetraz) 3 ] and [Au(Hdamp-C 1 )Cl(Spur)]Cl have been elucidated showing the gold atoms in distorted square-planar co-ordination environments. Generally, one or more hydrogen atoms of the heterocyclic ligands and/or the NMe 2 H ϩ group form hydrogen bonds in the solid-state structures. The reaction of Na[AuCl 4 ] with Na(Smetetraz) and [NEt 4 ]Br yields bright red crystals of [NEt 4 ][Au(Smetetraz) 4 ], the first structurally characterized gold() complex with four monodentate thiolate ligands. The structure of the complex shows well separated [Au(Smetetraz) 4 ] Ϫ anions with Au᎐S distances of 2.354(4) Å. Square-planar gold() complexes containing 2-(dimethylaminomethyl)phenyl-C 1 ,N, (damp-C 1 ,N) Ϫ , have been known since 1984. 1 Key compounds are the dichloro and diacetato complexes [Au(damp-C 1 ,N)Cl 2 ] (1a) and [Au(damp-C 1 ,N )-(CH 3 CO 2 ) 2 ] 1 (1b) which recently have been studied by structural analysis 2 showing distorted square-planar co-ordination spheres for the gold atoms. During ligand exchange reactions the chloro or acetato ligands are preferably replaced. 2-9 Only a few examples are reported where the Au᎐N bond is cleaved. 9 However, to our knowledge, protonation of the liberated N(CH 3 ) 2 group has not yet been observed for gold compounds.

Technetium Complexes with 2-Mercapto-methyltetrazolate

“…The Tc±N(10) bond of 1.612 (8) is short which is often observed for five-coordinate complexes [2]. The observed C±S bond lengths between 1.70 and 1.77 A Ê are in a similar range to those found in gold(III) complexes with the same ligand where also thiolate coordination has been found [5]. Each two neighbouring ± Smetetraz ligands have their methyl groups above and below the S 4 plane, preventing the four-fold crystallographic axis found in 4 ], can be prepared by the reaction of (Bu 4 N) [TcOCl 4 ] with the sodium salt of the ligand.…”

Functional models of [Fe—S] nitrosyl proteins

“…109 Triazole and tetrazolethiols possess a broad spectrum of antimicrobial and fungicidal properties, block the formation of ribosomes and DNA, and inhibit ribofla vin biosynthesis. [110][111][112][113] It is known that pyridine 2 thiol (2) serves as a potent antimetabolite of pyrimidine bases of nucleic acids. Its pharmacological action is analogous to that of 6 thioguanine and 6 mercaptopurine, which are used in clinical practice for the treatment of acute leukemia.…”

Metal derivatives of tetrazoles

“…Compound 181 exhibits an antitumour activity; therefore, studies of the ligand exchange in this complex and the biological activities of the products obtained arouse considerable interest. 313,317 The replacement of chloride ions in complex 181 by successive treatment with diphenylthiocarbazone and 5-mercapto-1-methyltetrazolate anion to give mixed-ligand complex has been carried out. 317 The 5-mercapto-1-methyltetrazolate anion also reacts as a monodentate ligand to form technetium(III) and (V) complexes 183 ± 185.…”