[Sm₆O₄(cbz)₁₀(thf)₆]·2C₇H₈: A Polynuclear Samarium Oxo Cluster Obtained from Carbazole-Driven Oxidation of Samarium Nanoparticles

Abstract

Zerovalent samarium nanoparticles (1.7 ± 0.2 nm in size) are used as the starting material to prepare single crystals of the novel polynuclear samarium oxo cluster [Sm6O4(cbz)10(thf)6]·2C7H8. The reaction is performed by oxidation with carbazole (CbzH) in tetrahydrofuran (THF) at 50 °C with subsequent crystallization in toluene (C7H8). The oxo cluster contains noncharged molecular units with a central Sm6O4 core. Single-crystal structure analysis and infrared spectroscopy confirm the oxidation of CbzH with the formation of (cbz)−. Polynuclear carbazole complexes are generally rare and here prepared using metal nanoparticles as a reactive starting material for the first time. The reaction with CbzH as a sterically demanding ligand exemplarily shows the feasibility of rare-earth-metal nanoparticles for obtaining new compounds with complex composition and structure.

Hydride Abstraction from a BH4– Anion in a Carbazolyl Lanthanum Boranate

“…Furthermore, the borohydride complex 3 was also characterized in solution by NMR spectroscopy. However, only the proton and carbon shifts for the flanking aryl groups are observable in the 1 H and 13 spectrum shows the expected three signals for the different boron species. The chemical shift of the boranate BH 4 moiety changes slightly, and the resonance of the amidoborane (−8.1 ppm) appears as a very broad singlet, whereas for the hydridoborate (−24.7 ppm, 1 J BH = 74.5 Hz) a doublet is observed.…”

“…The formation of borane results in a N−BH 3 moiety with a bond distance N1−B1 of 1.584(10) Å, which is comparable to other covalent bond lengths in similar complexes. 40 The synthesized heteroleptic complexes 1, 2, and 3 were characterized by 1 H, 13 C{ 1 H}, and 11 B NMR spectroscopy. and C 4,5 protons of the carbazole backbone were observed as doublets at 7.74 and 8.27 ppm, respectively.…”

“…Carbazole as a closely related N-containing scaffold shows similar behavior. For instance, the parent carbazole (Cbz) shows typically s coordination, i.e., in Trifonov’s [Dy(Cbz) 2 py 4 ] + (Scheme , A , py = pyridine) or Feldmann’s complex [Sm 6 O 4 (Cbz) 10 (THF) 6 ] . In contrast, the 1,3,6,8-tetra- tert -butylcarbazolyl ligand acts as exclusive p ligand ( B , C ). − In many instances, tridentate pincer ligands have been constructed from the carbazole scaffold by means of substitution at positions 1 and 8, and some of them have been applied in lanthanide chemistry as well, for instance with tetrazoles ( D ), oxazoles ( E ), , carbenes, and phosphines. − …”