Hexaazamacrocyclic nickel and copper complexes and their reactivity with tetracyanoquinodimethane.
The hexaazamacrocycle 1,4,7,10,13,16-hexaazacyclooctadecane, [18]ane-N6, forms mono- and dinuclear derivatives with copper chloride depending on the reaction stoichiometries and times. The mononuclear derivative, [Cu([18]ane-N6)]Cl2.H2O, presents the macrocycle wrapped around the metal atom in a distorted octahedral coordinative environment, while the dinuclear derivative, [Cu2([18]ane-N6)Cl2]Cl2.4H2O, is formed by a central Cu2Cl2 core surrounded by an almost planar macrocycle. The crystal structure of both derivatives is stabilized by a network of hydrogen bonds involving the amine macrocyclic groups, the chloride anions, and the crystallization water molecules. The copper atoms in the dinuclear derivative show a strong antiferromagnetic coupling, as expected for the crystal structure parameters. A mononuclear nickel derivative has also been obtained from nickel nitrate by following the same synthetic procedure. These compounds react with TCNQ salts with formation of two types of derivatives, [M([18]ane-N6)](TCNQ)2 and [M([18]ane-N6)](TCNQ)4, depending on the use of radical-anionic or mixed-valence TCNQ salts in the reaction. The crystal structures of the nickel derivatives show that the former derivatives are built up by macrocyclic metal cations surrounded by dimeric dianions (TCNQ)22-, either isolated or stacked along the crystal. The derivative with four TCNQ units/formula consists of alternated chains of metallomacrocyclic cations and stacked TCNQ anions. The crystal parameters suggest that every TCNQ holds approximately 0.5 electrons and overlaps with a neighboring unit to form dimeric monoanions, (TCNQ)2-.
Ballester
Loreto
L
Departamento de Química InorgAnica I, Facultad de Ciencias Químicas, Universidad Complutense, 28040-Madrid, Spain.
Gutiérrez
Angel
A
Perpiñán
M Felisa
MF
Sánchez
Ana E
AE
Fonari
Marina
M
Gdaniec
Maria
M
D001372:Aza Compounds / Q000138:chemical synthesis*; D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D003500:Cyclization; D004574:Electromagnetic Fields; D007202:Indicators and Reagents; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared
D001372:Aza Compounds; D007202:Indicators and Reagents; D009570:Nitriles; C013703:tetracyanoquinodimethane; D003300:Copper; D009532:Nickel