Zur Kristallchemie der Oxopalladate

Abstract

Im Übersichtsbeitrag wird die Kristallchemie der Oxopalladate systematisiert. Für die Ordnung wird der Grad der Vernetzung planarer Polygone herangezogen. Ausgehend von zueinander isolierten PdO4‐Polygonen steigt der Vernetzungsgrad über [PdO3]‐ und [PdO2]‐Ketten, quadratische [Pd4O8]‐Röhren zu planaren [PdO2]‐Netzen. In die dritte Dimension gehen aus planaren PdO4‐Polygonen aufgebaute gewellte Netze, endlich breite Gerüste und geschlossene dreidimensionale Vernetzungen. Bemerkenswert ist die Ausbildung von zueinander isolierten Pd6O12‐Ringen und Käfigstrukturen (Tl+Pd12O24‐Makropolyeder) aus drei sich kreuzenden Pd4(Lücke)4O16‐Ringen. In Kombination mit lone pair (LP) aktiven Elementen werden die planaren PdO4‐Polygone zu einem PdO4LP2‐Oktaeder ergänzt. Pd4+ in oktaedrischer Sauerstoffkoordination entspricht der Erwartung. Ungewöhnlich ist jedoch tetraedrisch koordiniertes Pd4+, oktaedrisch und trigonal prismatisch koordiniertes Pd2+, insbesondere aber gemischtvalentes Pd2, 5+ und Palladium mit der Valenz Pd3+. Metallreiche Verbindungen neigen zur Clusterbildung.

Homoleptic imidazolate frameworks 3∞[Sr1−xEux(Im)2]—hybrid materials with efficient and tuneable luminescence

“…16 Detailed description on the Experimental of 1-3 is found in the ESIz including the results of IR and CHN-analysis. z The trivalent oxidation state is stable for Eu (E 0 Ln II/III = 0.35 V).…”

“…The problem is overcome by activation of the metals by electride formation in liquid NH 3 . 16,18 The metals equally dissolve under formation of ammine complexes [M(NH 3 ) x ] 2+ 18 and solvated electrons identified by a dark blue solution. Upon removal of ammonia the metals are reformed as very small metal particles that fairly improve the mixing for the subsequent reaction with imidazole.…”

“…(1) are obtained by reactions of the metals europium and strontium together with a melt of the ligand 1H-imidazole in excellent yields up to 90%.y Solvent free reaction conditions avoid co-coordination of solvent molecules and drive the system towards homoleptic products. 16 Strontium and europium form isotypic compounds that allow complete mixing throughout all molar ratios as the two ions Sr 2+ and Eu 2+ have almost identical ionic radii. 17 Also the monometallic frameworks (1) were prepared, corroborated by single crystal X-ray and powder diffraction.…”

Palladium(IV) in an Oxoanionic Environment: The XeF2 Assisted Synthesis of [Pd(S2O7)3]2−

“…[4] Oxygen should also be a suitable oxidant for the preparation of tetravalent palladium compounds and, indeed, a number of complex oxides are known which have been obtained in most cases from high-pressure reactions. [5] Interestingly, according to recent investigations the binary oxide PdO 2 , which was reported to be accessible at high oxygen pressure with a rutile type of structure, [6] is not stable under ambient conditions. [7] Two 10À .…”

Influence of the Formation of Ternary Oxide of Pd and Na Supported on Alumina Catalysts for the Room Temperature Hydrodechlorination of Chlorobenzene

“…The formation of Na 2 Pd 3 O 4 is seen only in the case of PdNa-4 and PdNa-5 catalysts. The formation of ternary oxides of Pd and Na has also been reported in the literature [30,31]. Wilhelm [32] reported the formation of Na 2 Pd 3 O 4 species in Na-Pd-O system.…”