Adducts of rhodium(II) tetraacetate with some nitrogenous organic ligands: application of natural abundance 15N and 13C CPMAS NMR spectroscopy.
Adducts of rhodium(II) tetraacetate with some nitrogenous organic ligands: 1-azabicyclo[2,2,2]octane 1, 1,2-diazabicyclo[2,2,2]octane 2, pyrazine 3, pyrimidine 4, [1,3,5]triazine 5 and 1,3,5,7-tetraazatricyclo[3,3,1,1(3,7)]decane 6 have been investigated by means of natural abundance (13)C and (15)N CPMAS nuclear magnetic resonance (NMR) spectroscopy. 1-Azabicyclo[2,2,2]octane 1 having one nitrogen atom in the molecule produces either the 1:1 or 1:2-adduct depending on the reagent molar ratio; some features of its (13)C CPMAS NMR spectra suggest the dimeric structure of the 1:1-adduct. Multifunctional ligands having more than one nitrogen atom in a molecule yield the adducts insoluble in common organic solvents. Elemental analysis and NMR experiments have revealed that 1,2-diazabicyclo[2,2,2]octane, pyrazine, pyrimidine and [1,3,5]triazine produced adducts in the form of 1:1 polymeric chains. 1,3,5,7-tetraazatricyclo[3,3,1,1(3,7)]decane yields the adduct containing ligand and metal salt in the molar ratio of 3:4. The (15)N chemical shift change caused by the Rh-N bond formation (Deltadelta parameter) varies from ca. -9 ppm for aliphatic ligands to ca. -40 ppm for heteroaromatic species. The NMR findings have been supported by theoretical calculation (density functional calculation (DFT), LanLD2Z//B3LYB level) of molecular geometry, energy and chemical shieldings.
Jaźwiński
Jarosław
J
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa, Poland. jarjazw@icho.edu.pl
Kamieński
Bohdan
B
D000085:Acetates / Q000737:chemistry*; D002247:Carbon Isotopes / Q000737:chemistry*; D003198:Computer Simulation; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D017672:Nitrogen Compounds / Q000737:chemistry*; D009587:Nitrogen Isotopes / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*
D000085:Acetates; D002247:Carbon Isotopes; D008024:Ligands; D017672:Nitrogen Compounds; D009587:Nitrogen Isotopes; D012238:Rhodium