Preparation and characterization of Cr(III), Mn(II), Fe(II), Co(II) and Ni(II) complexes of a hexaazadithiophenolate macrocycle.
The ligating properties of the 24-membered macrocyclic dinucleating hexaazadithiophenolate ligand (L(Me))2- towards the transition metal ions Cr(II), Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) have been examined. It is demonstrated that this ligand forms an isostructural series of bioctahedral [(L(Me))M(II)2(OAc)]+ complexes with Mn(II) (2), Fe(II) (3), Co(II) (4), Ni(II) (5) and Zn(II) (6). The reaction of (L(Me))2- with two equivalents of CrCl2 and NaOAc followed by air-oxidation produced the complex [(L(Me))Cr(III)H2(OAc)]2+ (1), which is the first example for a mononuclear complex of (L(Me))2-. Complexes 2-6 contain a central N3M(II)(mu-SR)2(mu-OAc)M(II)N3 core with an exogenous acetate bridge. The Cr(III) ion in is bonded to three N and two S atoms of (L(Me))2- and an O atom of a monodentate acetate coligand. In 2-6 there is a consistent decrease in the deviations of the bond angles from the ideal octahedral values such that the coordination polyhedra in the dinickel complex 5 are more regular than in the dimanganese compound 2. The temperature dependent magnetic susceptibility measurements reveal the magnetic exchange interactions in the [(L(Me))M(II)2(OAc)]+ cations to be relatively weak. Intramolecular antiferromagnetic exchange interactions are present in the Mn(II)2, Fe(II)2 and Co(II)2 complexes where J = -5.1, -10.6 and approximately -2.0 cm(-1) (H = -2JS1S2). In contrast, in the dinickel complex 5 a ferromagnetic exchange interaction is present with J = +6.4 cm(-1). An explanation for this difference is qualitatively discussed in terms of the bonding differences.
Laboratoire de Chimie Inorganique et Matérieux Moléculaires, Université Pierre et Marie Curie 6, case courier 42, F-75005, Paris, France.
Yves
Y
Journaux
Thorsten
T
Glaser
Gunther
G
Steinfeld
Vasile
V
Lozan
Berthold
B
Kersting
D018360:Crystallography, X-Ray; D004563:Electrochemistry; D008024:Ligands; D047028:Macrocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D008280:Magnetics; D019216:Metals, Heavy / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature
D008024:Ligands; D047028:Macrocyclic Compounds; D019216:Metals, Heavy; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds