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The functionalization of (R,R)-S,S′-di-tert-butylferrocene-1,1′-disulfoxide by deprotolithiation-electrophilic trapping sequences was studied towards polysubstituted, enantiopure derivatives for which the properties were determined. While the 2,2′-disubstituted ferrocene derivatives were obtained as expected, subsequent functionalization of the 2,2′-di(phenylthio) and 2,2′-bis(trimethylsilyl) derivatives occurred primarily at the 4- or 4,4′-positions. This unusual regioselectivity was discussed in detail in light of pKa values and structural data. The less sterically hindered 2,2′-difluorinated derivative yielded the expected 1,1′,2,2′,3,3′-hexasubstituted ferrocenes by the deprotometallation-trapping sequence. Further functionalization proved possible, leading to early examples of 1,1′,2,2′,3,3′,4,4′-octa, nona and even decasubstituted ferrocenes. Some of the newly prepared ferrocene-1,1′-disulfoxides were tested as ligands for enantioselective catalysis and their electrochemical properties were investigated. [ABSTRACT FROM AUTHOR]

1-(5-Amino-3-azapentyl)tetrazole dihydrochloride (HL·2HCl) was prepared by heterocyclization of diethylenetriamine with triethyl orthoformate and sodium azide followed by treatment with potassium carbonate and hydrochloric acid. The reaction of CuCl2, HL·2HCl and triethylamine (NEt3) in a molar ratio of 1 : 1 : 3 in water was found to generate a novel organometallic tetrazole derivative Cu2L2Cl2. This compound is present as a binuclear centrosymmetric molecular complex, in which C-deprotonated tetrazole L acts as a chelating ligand via the two amino N and tetrazole ring C coordination sites and the two copper atoms are linked together through two tetrazole ring N4–C5 bridges. This complex is the first organocopper tetrazole derivative. When the molar ratio of the reagents in the abovementioned reaction was changed to 1 : 2 : 2, the complex Cu(HL)2Cl2 was formed along with Cu2L2Cl2. Pure Cu(HL)2Cl2 was isolated after reaction of the reagents in a molar ratio of 1 : 3 : 6. The complex Cu(HL)2Cl2 is present as a mononuclear molecular complex, with a chelating coordination mode of HL via the two amino N atoms only. Both complexes as well as HL·2HCl were characterized by single-crystal X-ray analysis. [ABSTRACT FROM AUTHOR]

1-(5-Amino-3-azapentyl)tetrazole dihydrochloride (HL·2HCl) was prepared by heterocyclization of diethylenetriamine with triethyl orthoformate and sodium azide followed by treatment with potassium carbonate and hydrochloric acid. The reaction of CuCl2, HL·2HCl and triethylamine (NEt3) in a molar ratio of 1 : 1 : 3 in water was found to generate a novel organometallic tetrazole derivative Cu2L2Cl2. This compound is present as a binuclear centrosymmetric molecular complex, in which C-deprotonated tetrazole L acts as a chelating ligand via the two amino N and tetrazole ring C coordination sites and the two copper atoms are linked together through two tetrazole ring N4–C5 bridges. This complex is the first organocopper tetrazole derivative. When the molar ratio of the reagents in the abovementioned reaction was changed to 1 : 2 : 2, the complex Cu(HL)2Cl2 was formed along with Cu2L2Cl2. Pure Cu(HL)2Cl2 was isolated after reaction of the reagents in a molar ratio of 1 : 3 : 6. The complex Cu(HL)2Cl2 is present as a mononuclear molecular complex, with a chelating coordination mode of HL via the two amino N atoms only. Both complexes as well as HL·2HCl were characterized by single-crystal X-ray analysis. [ABSTRACT FROM AUTHOR]

1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2]4+ (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N4-coordination, and two ligands L providing two tetrazole ring N3,N4 bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions. Complex 2 includes a linear trinuclear complex cation [Cu3L6(H2O)6]6+ (the S6 symmetry point group), in which neighbouring copper(ii) cations are linked by three ligands L via tetrazole ring N3,N4 bridges; central and terminal metal ions show octahedral CuN6 and CuN3O3 coordination cores, respectively. The temperature-dependent magnetic susceptibility measurements of complex 2 revealed that the copper(ii) ions were weakly ferromagnetically coupled showing a coupling constant J of 2.2 cm−1 {H = −2J(S1S2 + S2S3)}. The quantum-chemical investigation of the electronic structure and basicity of ligand L was carried out. [ABSTRACT FROM AUTHOR]

The functionalization of ( R , R )- S , S '-di- tert -butylferrocene-1,1'-disulfoxide by deprotolithiation-electrophilic trapping sequences was studied towards polysubstituted, enantiopure derivatives for which the properties were determined. While the 2,2'-disubstituted ferrocene derivatives were obtained as expected, subsequent functionalization of the 2,2'-di(phenylthio) and 2,2'-bis(trimethylsilyl) derivatives occurred primarily at the 4- or 4,4'-positions. This unusual regioselectivity was discussed in detail in light of p K a values and structural data. The less sterically hindered 2,2'-difluorinated derivative yielded the expected 1,1',2,2',3,3'-hexasubstituted ferrocenes by the deprotometallation-trapping sequence. Further functionalization proved possible, leading to early examples of 1,1',2,2',3,3',4,4'-octa, nona and even decasubstituted ferrocenes. Some of the newly prepared ferrocene-1,1'-disulfoxides were tested as ligands for enantioselective catalysis and their electrochemical properties were investigated.

1-(5-Amino-3-azapentyl)tetrazole dihydrochloride (HL·2HCl) was prepared by heterocyclization of diethylenetriamine with triethyl orthoformate and sodium azide followed by treatment with potassium carbonate and hydrochloric acid. The reaction of CuCl2, HL·2HCl and triethylamine (NEt3) in a molar ratio of 1 : 1 : 3 in water was found to generate a novel organometallic tetrazole derivative Cu2L2Cl2. This compound is present as a binuclear centrosymmetric molecular complex, in which C-deprotonated tetrazole L acts as a chelating ligand via the two amino N and tetrazole ring C coordination sites and the two copper atoms are linked together through two tetrazole ring N(4)-C(5) bridges. This complex is the first organocopper tetrazole derivative. When the molar ratio of the reagents in the abovementioned reaction was changed to 1 : 2 : 2, the complex Cu(HL)2Cl2 was formed along with Cu2L2Cl2. Pure Cu(HL)2Cl2 was isolated after reaction of the reagents in a molar ratio of 1 : 3 : 6. The complex Cu(HL)2Cl2 is present as a mononuclear molecular complex, with a chelating coordination mode of HL via the two amino N atoms only. Both complexes as well as HL·2HCl were characterized by single-crystal X-ray analysis.

1-(tert-Butyl)-1H-tetrazole (L) reacts with copper(ii) tetrafluoroborate hexahydrate to give the complexes [Cu2L8(H2O)2](BF4)4 (1) or [Cu3L6(H2O)6](BF4)6 (2) depending on the reaction conditions. These complexes, as well as compound L, were characterized using single crystal X-ray analysis. Complex 1 was found to comprise a dinuclear complex cation [Cu2L8(H2O)2](4+) (the Ci symmetry point group), with six tetrazole ligands L showing monodentate N(4)-coordination, and two ligands L providing two tetrazole ring N(3),N(4) bridges between the copper(ii) cations; water molecules complete the distorted octahedral coordination of the metal ions. Complex 2 includes a linear trinuclear complex cation [Cu3L6(H2O)6](6+) (the S6 symmetry point group), in which neighbouring copper(ii) cations are linked by three ligands L via tetrazole ring N(3),N(4) bridges; central and terminal metal ions show octahedral CuN6 and CuN3O3 coordination cores, respectively. The temperature-dependent magnetic susceptibility measurements of complex 2 revealed that the copper(ii) ions were weakly ferromagnetically coupled showing a coupling constant J of 2.2 cm(-1) {H = -2J(S1S2 + S2S3)}. The quantum-chemical investigation of the electronic structure and basicity of ligand L was carried out.

For the first time, a representative of the 2,5-disubstituted tetrazoles, namely, 2-tert-butyl-5-(2-pyridyl)-2H-tetrazole (L), has been found to participate in oxidative dissolution of copper powder in homometalic systems Cu0–L–NH4X–DMSO (X = Cl, SCN, ClO4) and heterobimetallic ones Cu0–Mn(OAc)2–L–NH4OAc–Solv (Solv = DMSO, DMF), providing the formation of molecular homometallic complexes [CuL2Cl2] (1), [CuL2(SCN)2] (2), and [CuL2(H2O)](ClO4)2 (3), heterobimetallic complex [Cu2MnL2(OAc)6] (4) from DMF solution and its mixture with complex [Cu2MnL2(OAc)6]·2DMSO (5) from DMSO solution. Free ligand L and complexes 1–4 were characterized by elemental analysis, IR spectroscopy, thermal and X-ray single crystal analyses, whereas complex 5 was characterized by X-ray analysis only. Compounds 1–3 are mononuclear complexes, with chelating coordination mode of L via the tetrazole ring N4 and pyridine ring N7 atoms. Heterobimetallic complexes 4 and 5 possess trinuclear structures, with a linear Cu–Mn–Cu arrangement of the metal atoms, linked by the acetate anions; each copper(II) atom is decorated by a chelating unit of L via the tetrazole ring N1 and pyridine ring N7 atoms in complex 4, and via the N4, N7 atoms in complex 5. Temperature-dependent magnetic susceptibility measurements of complex 4 revealed a weak antiferromagnetic coupling between the paramagnetic copper(II) and manganese(II) ions (J = −2.5 cm(−1), g(Cu) = 2.25 and g(Mn) = 2.01), with magnetic exchange through the acetato bridges.

2-Aryl-1,2,3-triazoles were synthesized by cyclization of the corresponding glyoxal arylosazones, generated from commercial arylhydrazines. The deproto-metallation of 2-phenyl-1,2,3-triazole was attempted using different 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal (Zn, Cd, Cu, Co, Fe) combinations, giving results in the case of Zn, Cd, and Cu. The lithium-zinc combination was next selected to apply the deprotonation-iodination sequence to all the 2-aryl-1,2,3-triazoles synthesized. The results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method.

A series of N-aryl and N-heteroaryl pyrazoles have been deproto-metallated using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination. Mono-, di-, and tri-iodides have been obtained after subsequent trapping with iodine, depending on the substrate and on the quantity of base used. The results have been discussed in the light of the CH acidities of the substrates, determined both in the gas phase and in THF solution using the DFT B3LYP method.