Mono and dinuclear half-sandwich platinum group metal complexes bearing pyrazolyl-pyrimidine ligands: Syntheses and structural studies

Syntheses and characterization of mono and dinuclear complexes of platinum group metals bearing benzene-linked bis(pyrazolyl)methane ligands

“…Complexes 13-14 exhibit a strong peak at d = 2.25 for the methyl protons of hexamethylbenzene ligand. In similar case with the Cp* analogues the arene ruthenium complexes also the chemical shifts of the arene ligands of ruthenium does not shifted down filed as compared to other Nbased ligands, this could be due to the geometrical orientation of arene ligands to the benzene-linker [24][25][26][27]. The molecular structure of complexes [{(g 5 -C 5 Me 5 )IrCl} 2 (l-L1)] 2+ ( [7](PF 6 ) 2 ), [{(g 6 -C 6 H 6 )RuCl} 2 (l-L1)] 2+ ( [9](PF 6 ) 2 ) and [{(g 6 -p-i PrC 6 H 4 Me)RuCl} 2 (l-L1)] 2+ ( [11](PF 6 ) 2 ) were determined by single crystal X-ray diffraction analysis.…”

“…The distance between the ruthenium atoms and the centroid of the C 6 [24,40]. The average Ir-C distances of complex 7 is slightly shorter (2.16 Å) than the corresponding Ru-C distances.…”

“…The mononuclear cationic complexes 1-4 exhibit ten distinct resonances assignable to pyrazole or methyl-pyrazole and benzene ring protons of the (L1 or L2) ligand indicating formation of mononuclear complexes. The methylic proton {-CH(Pz)2-} of ligand has shown two singlets at d = 8.29 and 7.78 corresponding to coordinated and uncoordinated to the metal complex indicating Table 1 Crystallographic and structure refinement parameters for complexes [7](PF 6 ) 2 Á2CH 3 CN, [9] other nitrogen-based ligands [21][22][23][24][25][26][27]. Complexes 9 and 10 exhibit a singlet at d = 5.40 and 5.48 for protons of benzene ligands, complexes 11 and 12 exhibits a doublet at d = 1.21 for the protons of the isopropyl methyl groups, a singlet at d = 1.26 for the methyl protons, a septet at d = 2.79 for the proton of the isopropyl group.…”

“…In recent years, we have been carrying out arene ruthenium and Cp* rhodium and iridium complexation reactions with a variety of nitrogen-based ligands [21][22][23][24][25][26][27] including pyrazolyl-pyrimidine, pyrazolyl-pyridazine and pyridyl-pyridazine ligands. All of these ligands after coordination with metal have given five membered chelating complexes; this is the first time that isolated six-membered chelating complexes with 1,4-bis{bis(pyrazolyl)-methyl}benzene (L1) or 1,4-bis{bis(3-methylpyrazolyl)methyl}benzene (L2) (Chart 1) ligands have been isolated with these metal complexes.…”

Development of biradical ligands toward [2×2] molecular grids

“…The bis(pyrazolyl)pyrimidine skeleton was prepared by means of aromatic nucleophilic substitution of 4,6-dichloropyrimidines [18]. 'Nitronyl nitroxides' (2-substituted 4,4,5,5-tetramethyl-4,5-dihydroimidazol-1-yloxyl 3-oxides) [19] and 'imino nitroxides' (2-substituted 4,4,5,5-tetramethyl-4,5-dihydroimidazol-1-yloxyls) [20] were originally developed as isolable organic radical groups by Ullman and co-workers in 1970's.…”