Über die Kristallstrukturen der Cyanokomplexe [Co(NH3)6][Fe(CN)6], [Co(NH3)6]2[Ni(CN)4]3 · 2 H2O und [Cu(en)2][Ni(CN)4]

Abstract

Professor Kurt Dehnicke zum 70. Geburtstag gewidmet Inhaltsu È bersicht. An Einkristallen der drei Titelverbindungen wurden ro È ntgenographische Strukturbestimmungen durchgefu È hrt. [Co(NH 3 ) 6 ][Fe(CN) 6 ] (a = 1098,6(6), c = 1084,6(6) pm, R3, Z = 3) kristallisiert im CsCl-artig aufgebauten [Co(NH 3 ) 6 ][Co(CN) 6 ]-Typ. [Co(NH 3 ) 6 ] 2 [Ni(CN) 4 ] 32 H 2 O (a = 805,7(5), b = 855,7(5), c = 1205,3(7) pm, a = 86,32(3), b = 100,13(3), c = 90,54(3)°, P1, Z = 1) zeigt ein damit verwandtes Kationengitter, dessen eine Lu È cke durch ein Anion und 2 H 2 O besetzt ist, wa È hrend die andere zwei zueinander parallele Anionen im Abstand von Ni . . . Ni: 423,3 pm entha È lt. Fu È r [Cu(en) 2 ][Ni(CN) 4 ] (a = 650,5(3), b = 729,0(3), c = 796,5(4) pm, a = 106,67(2), b = 91,46 (3), c = 106,96(2)°, P1, Z = 1) wurden die Ergebnisse einer fru È her vero È ffentlichten Strukturbestimmung besta È tigt. Die Verbindung ist schwach paramagnetisch und befolgt im Bereich T < 100 K das Curie-Weiss-Gesetz. Die Abstandsverha È ltnisse in den komplexen Ionen der untersuchten Verbindungen (Co±N: 195,7 bzw. 196,4 pm, Ni±C: 186,4 bzw. 186,9 pm) und ihre Wasserstoffbru È cken-Beziehungen werden diskutiert.

Preparation, spectroscopic and magnetic characterization of Cu(cyclam)M(CN)4 complexes exhibiting one-dimensional crystal structures (cyclam = 1,4,8,11-tetraazacyclotetradecane, M = Ni, Pd, Pt)

“…In compounds containing the [Cu(cyclam)] 2? cation studied to date, T values in the range of 0.769 for [Cu(cyclam)][Cu(CN) 4 ]Á H 2 O [30] to 0.807 for K[Cu(cyclam)][Fe(CN) 6 ]Á4H 2 O[14] were observed; Cu(en) 2 Ni(CN) 4 exhibits the T value of 0.785[26]. It is interesting to note that T values of 0.649 and 0.871 (Ni), and 0.653 and 0.862 (Pt) were reported recently for complexes [CuL 2 ][M(CN) 4 ]Á2H 2 O (M = Ni, Pt, L = trans-cyclohexane-(1R,2R)-diamine) with asymmetric axial bonds of which one is extremely long (3.120(8) (Ni) and 3.09(1) Å (Pt)) [31].…”

“…The intra-chain CuÁÁÁCu distance is 9.6471(6) Å . Moreover, in CENC, there is a further weaker hydrogen bonding interaction of the N-HÁÁÁN(:C) type to the nitrogen atom of the cyanido ligand, which is also weakly bound to the Cu(II) central atom, with corresponding geometric parameters of 3.211 Å and 151° [26]. It is interesting to note that in Cu(en) 2 Ni(CN) 4 a 2D magnetic ordering at 0.23 K was observed [8].…”

“…The Jahn-Teller radii for (1), (2), and (3) are 0.597, 0.580, and 0.622 Å [29]. The observed geometric parameters about the Cu(II) central atom are similar to those in Cu(en) 2 Ni(CN) 4 (CENC) [26]. [26] while even lower values of 121.6(2) and 120.64 (15)°were observed in the isostructural Cu(en) 2 Pd(CN) 4 and Cu(en) 2 Pt(CN) 4 complexes, respectively, indicating an ionic contribution to the character of the Cu-N bond [34,35].…”

“…The observed geometric parameters about the Cu(II) central atom are similar to those in Cu(en) 2 Ni(CN) 4 (CENC) [26]. [26] while even lower values of 121.6(2) and 120.64 (15)°were observed in the isostructural Cu(en) 2 Pd(CN) 4 and Cu(en) 2 Pt(CN) 4 complexes, respectively, indicating an ionic contribution to the character of the Cu-N bond [34,35]. These values are comparable to the Cu-N:C angle of 120.1(6)8 found in the simple, structurally prototypical compound Pt(CN) 3 (l-CN)-Cu(NH 3 ) 4 [36].…”

“…The observed absorption bands in all complexes are weakly split, indicating non-equivalency of the cyanido ligands. On the other hand, in the IR spectrum of similar Cu(en) 2 Ni(CN) 4 (en = 1,2-ethanediamine) only one absorption band positioned at 2,120 cm -1 was observed despite the same kind of non-equivalency of the cyanido ligands in the structure of this complex[26]. The coordination of the cyanido ligands to the central Ni(II) atom in (1) and thus formation of Ni-C coordination bonds is suggested by the observed absorption bands at 422 and 409 cm -1 , which are attributed to the d(Ni-CN) vibrations.…”