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Two Series of New Volatile Rare‐Earth Metal Tris(guanidinates) and Tris(amidinates)
Author(s) -
Tutacz Peter,
Harmgarth Nicole,
Zörner Florian,
Liebing Phil,
Hilfert Liane,
Engelhardt Felix,
Busse Sabine,
Edelmann Frank T.
Publication year - 2018
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201800393
Subject(s) - homoleptic , chemistry , tris , lanthanide , crystallography , metal , crystal structure , steric effects , molecule , stereochemistry , organic chemistry , ion , biochemistry
Two series of new volatile, homoleptic lanthanide(III) tris(guanidinate) and tris(amidinate) complexes were synthesized and fully characterized. Treatment of anhydrous rare‐earth metal(III) chlorides, Ln Cl 3 , with three equiv. of the aziridine‐derived lithium guanidinate Li[ c ‐C 2 H 4 NC(N i Pr) 2 ] ( 3 ) afforded the new homoleptic tris(guanidinate) complexes [ c ‐C 2 H 4 NC(N i Pr) 2 ] 3 Ln ( 4 ) ( Ln = Sc, Pr, Nd, Sm, Eu, Ho, Tm) in good yields (68–80 %). In a similar manner, the homoleptic tris(amidinate) complexes [ i PrC(N i Pr) 2 ] 3 Ln ( 6 ) Ln = Sc, Ce, Pr, Nd, Tb, Dy, Er, Yb) were prepared from Ln Cl 3 and the all‐ iso propyl‐substituted lithium amidinate Li[ i PrC(N i Pr) 2 ] ( 5 ) in a molar ratio of 1:3. Variable‐temperature 1 H NMR studies of the paramagnetic derivatives 4Pr – 4Tm revealed Curie‐type behavior. 1 H NMR spectroscopic data of complexes 6 indicated severe steric crowding due to the presence of nine iso propyl groups in these molecules. The molecular and crystal structures of eight title compounds ( 4Sc , 4Pr , 4Nd , 4Sm , 4Eu , 4Ho , 4Tm , and 6Er ) were determined through single‐crystal X‐ray diffraction studies. All complexes 4 exhibit similar molecular structures, comprising distorted octahedral molecular structures with small bite angles. Sublimation temperatures of 4 at 0.05 mbar were determined to be in the range between 151 °C ( 4Eu ) and 194 °C ( 4Tm ), whereas the complexes 6 sublime in the temperature range between 140 °C ( 6Sc ) and 180 °C ( 6Ce ), so that the use of these precursors in future ALD or CVD studies appears feasible.