Ein ferromagnetisches Carbodiimid: Cr₂(NCN)₃

Abstract

Strukturell gleich, magnetisch anders: Chrom(III)‐carbodiimid, das erste ferromagnetische Carbodiimid, wurde aus CrCl3 und ZnNCN synthetisiert und röntgenographisch charakterisiert. Trotz isostrukturellen Verhaltens zum antiferromagnetischen Cr2O3 weist Cr2(NCN)3 auf der Basis von SQUID‐Messungen und korrelierter DFT einen ferromagnetischen Grundzustand auf. Bei tiefen Temperaturen zeigt die Phase eine etwas größere Magnetisierung als Maghemit.

Reaction of an Osmium(VI) Nitrido Complex with Cyanide: Formation and Reactivity of an Osmium(III) Hydrogen Cyanamide Complex

“…Since the X-ray data of 3 show serious disorder on the osmium atom, a derivative, (PPh 4 ) 2 2 ] (3*), was also prepared for structural comparison. These compounds have also been characterized by 1 H NMR, IR, and UV/Vis spectroscopy; ESI-MS; and elemental analysis. In the 1 H NMR spectra of 3 and 3* (CD 3 CN), the imine À CH=N À resonance near d = 9 ppm (9.12 and 9.02 ppm in 1 and 2, respectively) is absent and is replaced by a new singlet at d = 7.27 and 7.29 ppm, respectively ( Figure S2 in the Supporting Information).…”

“…Although there are a number of transition-metal complexes of these ligands; [1][2][3][4][5][6][7][8][9] usually only structural, vibrational spectroscopy, and magnetic properties were studied, with little emphasis on the reactivity of the coordinated ligands. Cyanamide has been found to be a substrate of Mo-and V-nitrogenases; it can be reduced by these enzymes to CH 4 , CH 3 NH 2 , and NH 3 .…”

Ammonothermal Synthesis of Alkali‐Alkaline Earth Metal and Alkali‐Rare Earth Metal Carbodiimides: K5–xMx(CN2)2+x(HCN2)1–x(M= Sr, Eu) and Na4.32Sr0.68(CN2)2.68(HCN2)0.32

“…[28][29] The other observed bands are typical for carbodiimides (660 cm -1 : δ vibration, 1946 cm -1 : ν as vibration, above 3000 cm -1 : combination vibrations: ν as + 2δ and ν s + ν as ). [27] (6) 104.96 (9) The FT-IR spectra of K 4.40 Eu 0.60 (CN 2 ) 2.60 (HCN 2 ) 0.40 ( Figure S1 and Table S1, Supporting Information) show analog vibrational bands as explained for K 4.16 Sr 0.84 (CN 2 ) 2.84 (HCN 2 ) 0. 16 .…”

“…The crystal structure was determined by powder X-ray diffraction and refined by the Rietveld method [Na 4.32 and Na 2 CN 2 were prepared by reactions of Li 2 C 2 with Li 3 N and NaNH 2 with NaHCN 2 at elevated temperatures. [5,6] ZnCN 2 , which is used as starting material for syntheses of manganese and chromium carbodiimides by metathesis reaction, was prepared by reaction of ZnSO 4 and Na 2 CN 2 in aqueous solution and subsequent sintering at 843 K. [7][8][9] Besides the already mentioned alkali, alkaline earth, and transition metal carbodiimides, there are also rare earth metal carbodiimides like Eu(CN 2 ) 3 , synthesized by reaction of Eu 3 N 2 , NaN 3 , and carbon, and RE 2 (CN 2 ) 3 (RE = Yb, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er), produced by metathesis of Li 2 CN 2 with the corresponding rare earth metal chlorides at temperatures between 723 and 873 K. [10][11][12] Moreover, there are many other compounds containing the [NCN] 2-unit. [13][14][15] In 2012 Niewa et al illustrated that the ammonothermal technique, besides the common usage for crystal growth of GaN and synthesis of imides, amides and nitrides, is a promising method for the preparation of carbodiimides as well.…”

Festkörperchemie 2010

“…Dieses magnetische Verhalten wurde experimentell und durch quantenchemische Rechnungen nachgewiesen. Die Elektronenstruktur von grünem Cr2(NCN)3 ähnelt stark der des Cr2O3 und zeigt die Charakteristika sowohl eines Ladungstransfer‐ als auch eines Mott‐Hubbard‐Isolators 1…”