Cobalt(II) and nickel(II) complexes of some bidentate imidazoline ligands. Stereochemically dependent derealization in the imidazoline rings

Abstract

Tetrahedral and octahedral cobalt(II), and square and octahedral nickel(I1) complexes of 1,2-bis(2'-imidazolin-2'-yl)benzene, 1,2-bis(2'-imidazolin-2'-yl)ethane, and some imidazoline ring methyl substituted ligands are reported. The structures are confirmed by three X-ray structural analyses, magnetism, and electronic and vibrational (conventional and far i.r.) spectroscopy. Both cis and trans octahedral complexes of the type M(ligand)z(NCS)z [M = Co(II), Ni(II)] have been characterized, and none of these exhibit splitting of the v(CN)(NCS) absorption in the i.r. spectrum at room temperature. Low temperature studies reveal splitting of the v(CN) band in the cis isomers. Both 13C and I5N satellite absorption is identified. The delocalization of the double bond in the imidazoline rings in these complexes is discussed in terms of the i.r. and X-ray data.Canadian Journal of Chemistry, 48, 3076 (1970) We report here the metal complexing ability calibrant. The U.V. spectra were recorded with a Cary 14 of some novel bidentate ligands containing spectrometer and molecular weight data with a modified Gallenkamp Model 7665K semi-micro ebulliometer, imidazoline rings.the coordination calibrated with azobenzene and with benzoic acid. Infrachemistry of imidazole and its derivatives has red and far i.r. data were obtained with a Beckman IR 12 been extensively investigated (1, 2), studies of its spectrometer, and magnetic susceptibilities, via the Gouy dihydro derivative are restricted to the chemistry method with an Alpha 4 in. magnet calibrated with of 2,2,-bi-2-imidazoline (3). since the dihydro mercury cobalt tetrathiocyanate. Low temperature electronic and vibrational data were obtained with a Beckman ligand is somewhat simpler than imidazole, being V L T -~ Variable Temperature Cell, with quartz (elecnon-aromatic, it was thought that a study of its tronic), o r NaCl (i.r.) windows. Microanalyses were metal complexing ability might prove rewarding. substituted derivative (4, LME) were synthesized TO 1,3-diiminoisoindoline (6) (7.25 g, 0.05 mole) disby the phosphorus pentasulfide catalyzed reaction solved in boiling absolute ethanol, was added ethyleneof ethylenediamine (or 1,2-propanediamine) with diamine (6.2 g, 0.1 mole) and the mixture refluxed until phthalodinitrile or succinonitrile, a standard evolution of ammonia had ceased. The bulk of the solvent was removed by distillation at reduced pressure until route for the preparation Of imidazolines (4). crystallization occurred. The white crystalline product The ethane derivative LE has been reported (5) (6.1 g, 60% yield) was recrystallized from benzene. T h e but the other ligands were previously unknown. pure product melted at 174-175". Reaction of the parent ligands with cobalt and Method B (Based on (7)) nickel salts in alcohol led to the isolation of a 0-Dicyan~benzene (6.4 g, 0.05 mole), ethylenediamine series of square, tetrahedral, and octahedral (6.2 g, 0.1 mole), and a catalytic amount of phosphorus pentasulfide (20 mg) were mixed together. Upon applicacomp...

Dinuclear cobalt(II) complexes of a polyhydroimidazole ligand. Dinuclear (2:1) non-metallocyclic derivatives and dinuclear (1:1) metallocyclic complexes with a large, unoccupied central cavity

“…The lower energy absorptions in these regions associated with IV confirm the presence of coordinated bromine and suggest a structure similar to that in 111. These spectral bands are typical of pseudo-tetrahedral cobalt(I1) complexes with CoN2X2 chromophores and the absorption energies compare closely with bands observed for analogous, mononuclear complexes involving the ligands 1,2-bis(4,5-dihydroimidazol-2-yl)benzene(LP) and 1,2-bis(benzothiazo1-2-yl)ethane(BBTE), which have very similar donor groups producing equivalent, seven membered chelate rings (8,9). In DMF solution I11 and IV exhibit v3 and v, transitions with almost identical absorption energies.…”

Ti (IV) Complexes of Some Heterocyclic Ligands Synthesis, Characterization and Ethylene Polymerization Activity

“…A review of the literature revealed that 1,2-bis(2-benzothiazolyl)benzene and 1,2-bis(2-benzothiazolyl)ethane are frequently used as ligands and a considerable number of their complexes with late transition metals are reported [1][2][3][4][5][6] . Also, the nickel(II), cobalt(II) and copper(II) coordination chemistry of some tetradentate ligands involving benzothiazole functional groups has been published 7 .…”

“…The ligand 2, 6-bis (2-benzothiazolyl) pyridine9, 10, has been shown to behave as an N-3 donor in its complexes with manganese (II), iron (II) and nickel (II). 2,6-Bis(benzimidazolyl)pyridine 1,[11][12][13][14][15][16][17][18][19][20][21][22][23] , and 2,6-bis (benzoxazolyl)pyridine 24 , derivatives have been reported as ligands for transition metals in order to investigate the complexes for their structures and properties.…”

Bis(benzothiazolyl) titanium, zirconium and vanadium complexes as catalysts for ethylene polymerization

“…Benzothiazole contains a heterocyclic sulfur atom and a pseudo-imidazole functional group. A review of the literature revealed that 1,2-bis(2-benzothiazolyl)benzene and 1,2-bis(2-benzo-thiazolyl)ethane are frequently used as ligands and a considerable number of complexes with late transition metals are reported [7][8][9][10][11][12]. Also, the nickel(II), cobalt(II) and copper(II) coordination chemistry of some tetradentate ligands involving benzothiazole functional groups has been published [13].…”