Premium
Mixed Amido/Imido/Guanidinato Complexes of Tantalum: Effects of Ligand Substitution on Thermal Properties
Author(s) -
Baunemann Arne,
Winter Manuela,
Csapek Karoly,
Gemel Christian,
Fischer Roland A.
Publication year - 2006
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200600653
Subject(s) - chemistry , tantalum , isopropyl , amide , thermal decomposition , ligand (biochemistry) , nuclear magnetic resonance spectroscopy , stereochemistry , medicinal chemistry , crystal structure , crystallography , organic chemistry , biochemistry , receptor
Abstract Mixed amido/imido/guanidinato tantalum complexes [Ta(NR 1 R 2 ){C(NR 1 R 2 )(NR 3 ) 2 } 2 (NR 4 )] [R 1 ,R 2 = methyl, ethyl; R 3 = cyclohexyl (cy), isopropyl; R 4 = tert ‐butyl, n ‐propyl] have been synthesized by the insertion of carbodiimides into tantalum–amide bonds. All compounds have been characterized by means of NMR spectroscopy, mass spectrometry, and CHN analysis. Additionally, single crystal structures of five compounds ( 4 : R 1 = Me, R 2 = Et, R 3 = i Pr, R 4 = t Bu; 5 : R 1 , R 2 = Et, R 3 = i Pr, R 4 = t Bu; 6 : R 1 , R 2 = Me, R 3 = cy, R 4 = t Bu; 8 : R 1 , R 2 = Et, R 3 = cy, R 4 = t Bu; 9 : R 1 , R 2 = Et, R 3 = i Pr, R 4 = n Pr) have been determined and relevant structural issues are discussed. The thermal properties of all complexes have been investigated by TGA/DTA measurements. Thus, complexes originating from diisopropylcarbodiimide ( i Pr‐cdi) are significantly more volatile than complexes derived from dicyclohexylcarbodiimide (cy‐cdi). In contrast, variations of R 1 , R 2 , and R 4 have only a small impact on the thermal behavior of the complexes. Finally, selected compounds have been pyrolyzed at 600 °C, and the decomposition products studied by GC‐MS and 1 H NMR spectroscopy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)