Magnetic, electrochemical and spectroscopic properties of iron(III) amine-bis(phenolate) halide complexes.

Eight new iron(III) amine-bis(phenolate) complexes are reported. The reaction of anhydrous FeX(3) salts (where X = Cl or Br) with the diprotonated tripodal tetradentate ligands 2-tetrahydrofurfurylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H(2)L1, 2-tetrahydrofurfurylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenol), H(2)L2, and 2-methoxyethylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H(2)L3, 2-methoxyethylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenol), H(2)L4 produces the trigonal bipyramidal iron(III) complexes, L1FeCl (1a), L1FeBr (1b), L2FeCl (2a), L2FeBr (2b), L3FeCl (3a), L3FeBr (3b), L4FeCl (4a), and L4FeBr (4b). All complexes have been characterized using electronic absorption spectroscopy, cyclic voltammetry and room temperature magnetic measurements. Variable temperature magnetic data were acquired for complexes 2b, 3a and 4b. Variable temperature Mössbauer spectra were obtained for 2b, 3a and 4b. Single crystal X-ray molecular structures have been determined for proligand H(2)L4 and complexes 1b, 2b, and 4b.

Formation and X-ray Structures of PCP Ligand Based Platinum(II) and Palladium(II) Macrocycles.

The coordination behavior prior to C-M bond formation of the chelating aromatic PCP substrate DPPMH (3; DPPMH = 1,3-bis((diphenylphosphino)methylene)mesitylene) has been studied in order to determine the factors which control the complex formation of such ligands. Reacting 3 with (RCN)(2)MCl(2) (R = Me, Ph; M = Pd, Pt) and (COD)PtX(2) (X = Cl, Me; COD = 1,5-cyclooctadiene) resulted in the formation of several 8- and 16-membered mono- and binuclear palladium(II) and platinum(II) macrocycles: trans-[(DPPMH)PdCl(2)](2) (5), trans-[(DPPMH)PtCl(2)](2) (6), cis-(DPPMH)PtCl(2) (7), cis-(DPPMH)PtMe(2) (8), and cis-[(DPPMH)PtMe(2)](2) (9). Compounds 5-9 were fully characterized using NMR, FAB-MS, FD-MS, elemental analysis, and X-ray crystallography. Thermolysis of the bimetallic trans-[(DPPMH)PtCl(2)](2) (6) results in the formation of the monomeric cis-(DPPMH)PtCl(2) (7). The product formation depends on the neutral- (nitriles or COD) and anionic ligands (Cl and CH(3)) of the metal precursor. The molecular structures of trans-[(DPPMH)PdCl(2)](2) (5) and cis-[(DPPMH)PtMe(2)](2) (9) have been determined by complete single-crystal diffraction studies. Crystal data for 5: monoclinic, space group P2(1)/n with a = 14.547(3) Å, b = 17.431(4) Å, c = 27.839 (5) Å, beta = 99.56(2) degrees, V = 6961(3) Å(3), and Z = 4. The structure converged to R = 0.048 and R(w) = 0.049. Crystal data for 9: monoclinic, space group P2(1)/n with a = 19.187(4) Å, b = 19.189(4) Å c = 20.705(2) Å, beta = 103.41(3) degrees, V = 7415(3) Å(3), and Z = 4. The structure refinement converged to R = 0.0977 and R(w) = 0.2212.