title: Ammonothermal Synthesis, Crystal Structure, and Properties of the Ytterbium(II) and Ytterbium(III) Amides and the First Two Rare-Earth-Metal Guanidinates, YbC(NH)3 and Yb(CN3H4)3.
abstract: We report the oxidation-controlled synthesis of the ytterbium amides Yb(NH2)2 and Yb(NH2)3 and the first rare-earth-metal guanidinates YbC(NH)3 and Yb(CN3H4)3 from liquid ammonia. For Yb(NH2)2, we present experimental atomic displacement parameters from powder X-ray diffraction (PXRD) and density functional theory (DFT)-derived hydrogen positions for the first time. For Yb(NH2)3, the indexing proposal based on PXRD arrives at R3̅, a = 6.2477(2) Å, c = 17.132(1) Å, V = 579.15(4) Å(3), and Z = 6. The oxidation-controlled synthesis was also applied to make the first rare-earth guanidinates, namely, the doubly deprotonated YbC(NH)3 and the singly deprotonated Yb(CN3H4)3. YbC(NH)3 is isostructural with SrC(NH)3, as derived from PXRD (P63/m, a = 5.2596(2) Å, c = 6.6704(2) Å, V = 159.81(1) Å(3), and Z = 2). Yb(CN3H4)3 crystallizes in a structure derived from the [ReO3] type, as studied by powder neutron diffraction (Pn3̅, a = 13.5307(3) Å, V = 2477.22(8) Å(3), and Z = 8 at 10 K). Electrostatic and hydrogen-bonding interactions cooperate to stabilize the structure with wide and empty channels. The IR spectra of the guanidinates are compared with DFT-calculated phonon spectra to identify the vibrational modes. SQUID magnetometry shows that Yb(CN3H4)3 is a paramagnet with isolated Yb(3+) (4f(13)) ions. A CONDON 2.0 fit was used to extract all relevant parameters.
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Arno L
authors.initials: AL
authors.lastname: Görne
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: George
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: van Leusen
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Dück
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Jacobs
authors.affiliation: Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, Outstation at Spallation Neutron Source (SNS), and Chemical and Engineering Materials Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Naveen Kumar
authors.initials: NK
authors.lastname: Chogondahalli Muniraju
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University , Landoltweg 1, 52056 Aachen, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Dronskowski