N,N-Dialkyl-N'-benzoylthioureas, HR(1)R(2)btu, react under single deprotonation and form air-stable chelate complexes with common rhenium or technetium complexes such as (NBu(4))[MOCl(4)] (M = Re, Tc) or [ReOCl(3)(PPh(3))(2)]. Compositions and molecular structures of the products are strongly dependent on the precursors used and the reaction conditions applied. Reactions with [ReOCl(3)(PPh(3))(2)] in CH(2)Cl(2) give complexes of the general formula [ReOCl(2)(R(1)R(2)btu)(PPh(3))] (3), with the benzoyl oxygen atom of the chelating benzoylthiourea being trans to the oxo ligand, and/or Re(III) complexes of the composition [ReCl(2)(R(1)R(2)btu)(PPh(3))(2)] (4) with the PPh(3) ligands in trans positions to each other. In polar solvents such as MeOH, EtOH or acetone, corresponding reactions without addition of a supporting base only result in intractable brown solutions, from which no crystalline complexes could be isolated. The addition of NEt(3), however, allows the isolation of the bis-chelates [ReOCl(R(1)R(2)btu)(2)] (1) in good yields. In this type of complex, one of the chelating R(1)R(2)btu- ligands coordinates equatorially, while the second occupies the position trans to the oxo ligand with its oxygen atom. The latter compounds can also be prepared from (NBu(4))[ReOCl(4)] in MeOH when no base is added, while the addition of NEt(3) results in the formation of [ReO(OMe)(R(1)R(2)btu)(2)] (5) complexes with the methoxo ligand trans to O(2-). Compounds of the type 5 can alternatively be prepared by heating 1 in MeOH with addition of NEt(3). A reversible conversion of 5 into oxo-bridged dimers of the composition [{ReO(R(1)R(1)btu)(2)}(2)O] (6) is observed in water-containing solvents. Starting from (NBu(4))[TcOCl(4)], a series of technetium complexes of the type [TcOCl(R(1)R(2)btu)(2)] (2) could be prepared. The structures of such compounds are similar to those of the rhenium analogues 1. Reduction of 2 with PPh(3) in CH(2)Cl(2) gives Tc(III) complexes of the composition [TcCl(R(1)R(2)btu)(2)(PPh(3))] (7) having the chloro and PPh(3) ligands in cis positions. When this reaction is performed in the presence of excess chelating ligand, the Tc(III) tris-chelates [Tc(R(1)R(2)btu)(3)] (8) are formed.
[ReOCl3(PPh3)2] and [Re(NPh)Br3(PPh3)2] react at room temperature with equivalent amounts of N,N‐dialkyl‐N′‐benzoylthioureas (HR1R2btu) in CH2Cl2 under formation of the rhenium(V) complexes [ReOCl2(R1R1btu)(PPh3)] and [Re(NPh)Br2(R1R2btu)(PPh3)], respectively. The products are structurally analogous with the oxygen atoms of the benzoylthioureas binding in trans positions to the oxo or phenylimido ligands.
Prolonged reaction times result in the reduction of the oxo compound by the released PPh3 and the formation of rhenium(III) complexes of the composition [ReCl2(PPh3)2(R1R2btu)], while such a second reaction path is excluded for the phenylimido compound. Phenylimido species with more than one N,N‐dialkyl‐N′‐benzoylthioureato ligand could not be isolated, even when a large excess of HR1R2btu was used during the reaction.
N-[(Dialkylamino)(thiocarbonyl)]benzimidoyl chlorides react with functionalized amines such as 2-aminophenol, 2-methylaminopyridine, and 2-aminobenzoic acid in clean and high-yield procedures with the formation of the novel tridentate N-[(N'', N''-dialkylamino)(thiocarbonyl)]- N'-substituted benzamidine ligands H2L1, HL2, and H2L3. By starting from (NBu4)[MOCl4] (M = Re, Tc) or [ReOCl3(PPh3)2] and H2L1, a series of oxorhenium(V) and oxotechnetium(V) complexes of the composition [MOCl(L1)] were synthesized and characterized by spectroscopic methods and X-ray crystallography. The monomeric, five-coordinate compounds are air-stable and bind (L1)(2-) tridentate in the equatorial coordination sphere. Dimeric products of the compositions [(ReOCl(L2))2O] and [ReOCl(L3)]2 were isolated during reactions with HL2 and H2L3. While dimerization in [(ReOCl(L2))2O] is established via an oxo bridge, the metal atoms in [ReOCl(L3)]2 are connected by the carboxylic group of the ligand, and the product represents the first example of a high-oxidation state rhenium complex displaying such a bonding feature.
A novel Mn(II)-Gd(III) mixed-metal complex has been synthesized by one-pot reaction in methanolic solution of GdCl3, Mn(CH3OO)2∙4H2O and the organic ligand 2,6-dipicolinoylbis(N,N-diethylthiourea) (H2L) with 1:2:3 molar ratio. The structure of the complex was elucidated by IR spectroscopy, and single crystal X-ray diffraction, while the magnetic properties were studied by SQUID measurements in the temperature range of 10 ÷ 330 K. The complex is comprised of one Gd3+ ion, two Mn2+ cations, and three dianionic ligands {L}2- with the chemical composition of [GdMn2(L)3](PF6). The magnetic interaction between Mn(II) and Gd(III) is weakly ferromagnetic with J = + 0,027 cm-1.
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.