ABSTRACT
The bis(ß-diketone) o-pbaH(2) (o-phenylenebis(acetylacetone), 1) reacts readily with Cu(2+). Although this reaction was expected to yield a trimeric product (2) on geometric grounds, the binuclear complex Cu(2)(o-pba)(2) (3) is obtained instead. Materials containing Cu(2)(o-pba)(2) adopt a variety of colors, depending on the solvents used in preparation: dark green (microcrystalline, 3a), golden-brown (ansolvous, 3b), green-brown (CHCl(3)-C(6)H(6) solvate, 4), dark blue (nitrobenzene solvate, 5), or violet (toluene solvate, 6). Complexes 5 and 6 contain 1D chains of Cu(2)(o-pba)(2) molecules joined by weak Cu···O interactions. Crystalline adducts [Cu(2)(o-pba)(2)L](n) (7 and 8) containing 1D polymeric chains are also obtained upon reaction of 3 with bridging ligands (L = 1,2-bis(4-pyridyl)ethane or 4,4'-bipyridine, respectively). All of the new metal complexes except for 3a have been characterized by X-ray analysis.
Subject(s)
Coordination Complexes/chemistry , Copper/chemistry , Color , Coordination Complexes/chemical synthesis , Crystallography, X-Ray , Dimerization , Models, MolecularABSTRACT
A new family of 14-electron, four-coordinate iron(II) complexes of the general formula [Tp(tBu,Me)FeX] (Tp(tBu,Me) is the sterically hindered hydrotris(3-tert-butyl-5-methyl-pyrazolyl) borate ligand and X=Cl (1), Br, I) were synthesized by salt metathesis of FeX(2) with Tp(tBu,Me)K. The related fluoride complex was prepared by reaction of 1 with AgBF(4). Chloride 1 proved to be a good precursor for ligand substitution reactions, generating a series of four-coordinate iron(II) complexes with carbon, oxygen, and sulphur ligands. All of these complexes were fully characterized by conventional spectroscopic methods and most were characterized by single-crystal X-ray crystallographic analysis. Magnetic measurements for all complexes agreed with a high-spin (d(6), S=2) electronic configuration. The halide series enabled the estimation of the covalent radius of iron in these complexes as 1.24 Å.
