Synthesis and characterization of nickel(II) complexes of 14-membered hexaaza macrocyclic ligands “3,10-dialkyl-dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane” produced by the in situ one-pot template reaction of formaldehyde and 1,2-phenylenediamine with

New square-planar Ni(II) complexes of 14-membered hexaaza macrocyclic ligands {dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane, [Ni(Bzo2[14]aneN6)](ClO4)2 (1); 3,10-dimethyl-, [Ni(Me2Bzo2[14]aneN6)](ClO4)2 (2); 3,10-diethyl-, [Ni(Et2Bzo2[14]aneN6)](ClO4)2 (3); 3,10-dibutyl-, [Ni(Bu2Bzo2[14]aneN6)](ClO4)2 (4); 3,10-dibenzyl-, dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane [Ni((benzyl)2Bzo2[14]aneN6)](ClO4)2 (5); [Ni(Bzo2[14]aneN6)](PF6)2 (6); [Ni(Me2Bzo2[14]aneN6)](PF6)2 (7); [Ni(Et2Bzo2[14]aneN6)](PF6)2 (8); [Ni(Bu2Bzo2[14]aneN6)](PF6)2 (9); [Ni((benzyl)2Bzo2[14]aneN6)](PF6)2 (10); [Ni(Bzo2[14]aneN6)Cl2] (11); [Ni(Me2Bzo2[14]aneN6)Cl2] (12); [Ni(Et2Bzo2[14]aneN6)Cl2] (13); [Ni(Bu2Bzo2[14]aneN6)Cl2](14); [Ni((benzyl)2Bzo2[14]aneN6)Cl2] (15); [Ni(Bzo2[14]aneN6)(NCS)2] (16); [Ni(Me2Bzo2[14]aneN6)(NCS)2] (17); [Ni(Et2Bzo2[14]aneN6)(NCS)2] (18); [Ni(Bu2Bzo2[14]aneN6)(NCS)2] (19); [Ni((benzyl)2Bzo2[14]aneN6)(NCS)2] (20)} have been prepared by the in situ one-pot template synthesis (IOPTS) of formaldehyde and 1,2-phenylenediamine with alkyl amine or benzyl amine in the presence of the nickel(II) ion. The complexes of the hexaaza macrocycle have been characterized by elemental analyses, IR, FAB, UV–Vis and 1H NMR spectroscopy, conductometric and magnetic measurements. The nickel(II) complexes {[Ni(R2Bzo2[14]aneN6)](ClO4)2 (1–5) and [Ni(R2Bzo2[14]aneN6)](PF6)2 (6–10)} have square-planar coordination geometry in the solid state and in nitromethane. The spectra of all complexes show that the four secondary nitrogen atoms are coordinated to the nickel(II) ion. Synthesis, characterization and solution behavior of the nickel(II) complexes of hexaaza macrocycle (1–6) are reported. The stereochemistry around the metal ions in the {[Ni(R2Bzo2[14]aneN6)(NCS)2] and “[Ni(R2Bzo2[14]aneN6)Cl2]}” complexes is octahedral.

Graphical abstractNew square-planar Ni(II) complexes of 14-membered hexaaza macrocyclic ligands “dibenzo-3,5,9,10,12,14-hexaazacyclotetradecane, [Ni(R2Bzo2[14]aneN6)]2+ (R = H, Me, Et, Bu, Benzyl)” have been prepared by the in situ one-pot template synthesis (IOPTS) of formaldehyde and 1,2-phenylenediamine with alkyl amine or benzyl amine in the presence of the nickel(II) ion. The complexes of the hexaaza macrocycles have been characterized by elemental analyses, IR, FAB, UV–Vis and 1H NMR spectroscopy, conductometric and magnetic measurements. The spectra of all the complexes show that the four secondary nitrogen atoms are coordinated to the nickel(II) ion.Figure optionsDownload full-size imageDownload as PowerPoint slide