Journalartikel

Autorenliste: Müller-Buschbaum, K; Quitmann, CC

Jahr der Veröffentlichung: 2006

Seiten: 2678-2687

Zeitschrift: Inorganic Chemistry

Bandnummer: 45

Heftnummer: 6

ISSN: 0020-1669

DOI Link: https://doi.org/10.1021/ic0514795

Verlag: American Chemical Society

Abstract: 
Homoleptic dimeric dipyridylamide complexes of the rare earth elements are obtained by solvent-free oxidation reactions of the metals with melts of 2,2‘-dipyridylamine. As the thermal stabilities of the ligand as well as the amide complexes are limiting factors in these high-temperature syntheses, several different metal activation procedures have been investigated:  the formation of Ln amalgams and dissolution of the metals in liquid ammonia as well as coupling to microwaves. For comparison with a solvent that shows low solubility of the metals and products, reactions in 1,2,3,4-tetrahydroquinoline were also carried out. For all lanthanides and group 3 metals used homoleptic dimers of the formula [Ln2(Dpa)6], Ln = Ce (1), Nd (2), Sm (3), Ho (4), Er (5), Tm (6), Yb (7), and Sc (8) and Dpa- = (C5H4N)2N-, were obtained, all containing trivalent rare earth ions with a distorted square antiprismatic nitrogen coordination. Due to the large differences in the ionic radii of the metal ions, two different structure types are found that crystallize in the space groups P21/c and P21/n with the border of the two types being between Tm and Yb. The orientations of two 1,3/1,3-double chelating and linking dipyridylamide ligands (Dpa- = (C5H4N)2N-) result in different overall orientations of the dimers and thus two structure types. All compounds were identified by single-crystal X-ray analysis. Mid-IR, far IR, and Raman spectroscopy, microanalyses, and simultaneous DTA/TG as well as mass spectrometry regarding their thermal behavior were also carried out to characterize the products. Crystal data for the two types follow. Ce (1):  P21/n; T = 170(2) K; a = 1063.0(1), b = 1536.0(1), c = 1652.0(2) pm; β = 101.60(1)°; V = 2642.2(3) × 106 pm3; R1 for Fo > 4σ(Fo) = 0.046, wR2 = 0.120. Sc (8):  P21/c; T = 170(2) K; a = 1073.0(1), b = 1506.2(2), c = 1619.8(2) pm; β = 103.16(9)°; V = 2548.9(5) × 106 pm3; R1 for Fo > 4σ(Fo) = 0.038, wR2 = 0.091.

Harvard-Zitierstil: Müller-Buschbaum, K. and Quitmann, C. (2006) Homoleptic rare earth dipyridylamides [Ln(2)(N(NC5H4)(2))(6)], Ln = Ce, Nd, Sm, Ho, Er, Tm, Yb, and Sc: Metal oxidation by the amine melt and in 1,2,3,4-tetrahydroquinoline with the focus of different metal activation by amalgams, liquid ammonia, and microwaves, Inorganic Chemistry, 45(6), pp. 2678-2687. https://doi.org/10.1021/ic0514795

APA-Zitierstil: Müller-Buschbaum, K., & Quitmann, C. (2006). Homoleptic rare earth dipyridylamides [Ln(2)(N(NC5H4)(2))(6)], Ln = Ce, Nd, Sm, Ho, Er, Tm, Yb, and Sc: Metal oxidation by the amine melt and in 1,2,3,4-tetrahydroquinoline with the focus of different metal activation by amalgams, liquid ammonia, and microwaves. Inorganic Chemistry. 45(6), 2678-2687. https://doi.org/10.1021/ic0514795