113 research outputs found
Embracing ligands. A synthetic strategy towards new nitrogen-thioether multidentate ligands and characterization of the cobalt(III) complexes
The synthesis of the hexadentate ligand 2,2,9,9-tetra(methyleneamine)-4,7-dithiadecane (EtN(4)S(2)amp) is reported. The ligand is of a type in which bifurcations of the chain occur at atoms other than donor atoms. The cobalt(III) complex [Co(EtN(4)S(2)amp)](3+) (1) was isolated and characterized. The synthetic methodology also results in a number of by-products, notably 2,9,9-tris(methyleneamine)-9-methylenehydroxy-4,7-dithiadecane (Et(HO)N(3)S(2)amp) and an eleven-membered pendant arm macrocyclic ligand 6,10-dimethyl-6,10-bis(methyleneamine)-1,4-dithia-8-azaacycloundec-7- ene (dmatue). The complexes [Co(Et(HO)N(3)S(2)amp)](3+) (2), in which the alcohol is coordinated to the metal ion, and [Co(dmatue)Cl](2+) (4) were isolated and characterized. Et(HO)N(3)S(2)amp also undergoes complexation with cobalt(III) to produce two isomers endo-[Co(Et(HO) N(3)S(2)amp)Cl](2+) (endo-3) and exo-[Co(Et(HO) N(3)S(2)amp)Cl](2+) (exo-3), both with an uncoordinated alcohol group. endo- 3 has the alcohol positioned cis, and exo-3 trans, to the sixth metal coordination site. Reaction of 1 with isobutyraldehyde, paraformaldehyde and base in dimethylformamide results in the encapsulated complex [Co(1,5,5,9,13,13-hexamethyl-18,21-dithia-3,7,11,15-tetraazabicyclo[7.7.6]docosa- 3,14-diene)](ClO4)(3) . 2H(2)O ([Co(Me(6)docosadieneN(4)S(2))](3+) ( 5). All complexes have been characterized by single crystal X-ray study. The low-temperature (11 K) absorption spectrum of 1 has been measured in Nafion films with spin-allowed (1)A(1g) --> T-1(1g) and (1)A(1g) --> T-1(2g) and spin forbidden (1)A(1g) --> T-3(1g) and (1)A(1g) --> T-3(2g) bands observed. The octahedral ligand-field parameters were determined (10Dq = 22570 cm(-1), B = 551 cm(-1); C = 3500 cm(-1)). For 5 10Dq and B were determined (20580 cm(-1); 516 cm(-1), respectively) and compared with those for similar expanded cavity complexes [Co(Me(8)tricosatrieneN(6))](3+) and [Co(Me(5)tricosatrieneN(6))](3+)
ChemInform Abstract: Alkyl Hydroperoxide Oxidation of Alkanes and Alkenes with a Highly Active Mn Catalyst.
ChemInform Abstract: STRUCTURAL CHARACTERIZATION OF A NOVEL PLATINUM(IV) COMPLEX PRODUCED BY DEPROTONATION OF COORDINATED AMINO GROUPS OF THE RIGID LIGAND CIS,CIS-1,3,5-TRIAMINOCYCLOHEXANE
ChemInform Abstract: MODELL FUER DIE CIRCULARDICHROISMUS-STOERUNGEN, DIE BEI IONENPAARBILDUNG ZWISCHEN TRIS-(DIAMIN)-METALLCHELATEN UND GEWISSEN POLYOXYANIONEN AUFTRETEN
ChemInform Abstract: NUCLEAR MAGNETIC RESONANCE STUDIES OF CONFIGURATION AND LIGAND CONFORMATION IN PARAMAGNETIC OCTAHEDRAL COMPLEXES OF NICKEL(II) PART 9, 1,3-DIAMINE CHELATES
ChemInform Abstract: Assembly of High-Valent Oxomanganese Clusters in Aqueous Solution. Redox Equilibrium of Water-Stable Mn3O4+ 4 and Mn2O3+ 2 Complexes.
ChemInform Abstract: CONFORMATIONS OF (1,3-DIAMINE)PLATINUM(II) CHELATES AS STUDIED BY CARBON-13 AND PROTON NMR SPECTROSCOPY
NUCLEAR MAGNETIC RESONANCE STUDIES OF CONFIGURATION AND LIGAND CONFORMATION IN PARAMAGNETIC OCTAHEDRAL COMPLEXES OF NICKEL(II) VIII. Tridentate Ligands Containing Oxygen Donors
The Infra-red Spectra of Complexes with Planar Dithio Oxamides. Part II: The Pd(LH2) 2X2 Complexes
- …