Verdazyl radicals as oligopyridine mimics: structures and magnetic properties of M(II) complexes of 1,5-dimethyl-3-(2,2'-bipyridin-6-yl)-6-oxoverdazyl (M = Mn, Ni, Cu, Zn).

The verdazyl radical 1,5-dimethyl-3-(2,2'-bipyridin-6-yl)-6-oxoverdazyl (3) was prepared, and its homoleptic metal complexes M(3)(2)(2+).2X(-) (5, M = Mn(II); 6, M = Ni(II); 7, M = Cu(II); 8, M = Zn(II); X = ClO(4), PF(6)) were characterized by single-crystal X-ray diffraction and variable-temperature magnetic susceptibility measurements. Relevant crystallographic parameters are as follows: 5, monoclinic space group Pna2(1), a = 18.

Effective aromaticity of tricarbonylchromiumbenzene, about 25 enhanced over that of benzene: structural evidence from a complexed benzannulene.

The tricarbonylchromium complex of 2,7-di-tert-butyl-trans-12c,12d-dimethylbenzo[e]dihydropyrene is prepared in 65% yield from the parent annulene. Analysis of the (1)H NMR spectrum leads to coupling constant data and Günther's "Q" value data which unequivocally indicate that the tricarbonylchromiumbenzene moiety behaves like an aromatic system of greater bond fixing ability, aromaticity, than benzene itself; this analysis is supported by X-ray structural data and by the rotational position of the tricarbonyl podal. Analysis of chemical shift data indicates that the tricarbonylchromium benzene moiety has about 25% enhanced "aromaticity" over that of benzene.

Synthesis and coordination chemistry of a water-soluble verdazyl radical. structures and magnetic properties of M(H2O)2(vdCO2)(2).2H2O (M = Co, Ni; vdCO2 = 1,5-dimethyl-6-oxo-verdazyl-3-carboxylate).

The synthesis of a verdazyl radical with a carboxylate substituent renders the radical highly soluble in water, thereby permitting the aqueous synthesis of Ni(II) and Co(II) verdazyl complexes which have been structurally and magnetically characterized.

Synthesis and structure of a new macrotricyclic ligand that encapsulates lithium and transition metal ions.

A new macrotricyclic ligand, L3 with an N4S2 donor set that encapsulates lithium and transition metal ions has been synthesized from the tetraazamacrocycle cyclam.