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Achtfachkoordination von Cadmium(II) und sekundäre Metall—Ligand-Bindungen in [Cd(NO 3 ) 2 (C 12 H 22 N 6 )] und [Cd(C 12 H 22 N 6 ) 2 (BF 4 ) 2 / Eight-Coordination of Cadmium(II) and Secondary Metal —Ligand Bonds in [Cd(NO 3 ) 2 (C 12 H 22 N 6 )] and [Cd(C 12 H 22 N 6 ) 2 (BF 4 ) 2

1988; De Gruyter; Volume: 43; Issue: 12 Linguagem: Inglês

10.1515/znb-1988-1210

1865-7117

Henry Strasdeit, Siegfried Pohl,

Synthesis and Characterization of Heterocyclic Compounds

Abstract [Cd(NO 3 ) 2 (C 12 H 22 N 6 )] (1), [Cd(C 12 H 22 N 6 ) 2 ](BF 4 ) 2 (2), and [Cd(C 12 H 22 N 6 ) 2 ](ClO 4 ) 2 (3) are obtained from methanolic solutions by reaction of 2,5,8,10,13,16-Hexaazapentacyclo[ 8.6.1.125.0918.0l3,7]octadecane (C 12 H 22 N 6 ) with Cd(NO 3 ) 2 -4H 2 O, Cd(BF 4 ) 2 , and Cd(ClO 4 ) 2 · 6H 2 O, respectively. 1 crystallizes in the monoclinic space group C 2 /c with a = 10.346(1), b =18.162(1), c - 10.462(1) Å, β = 112.95(1)°, and Z = 4. 2 is monoclinic, space group P2 1 /n, a = 16.958(1), b = 10.653(1), c = 18.747(1) Å, β= 112,66(1)°, and Z = 4. The X-ray structures of 1 and 2 were refined to R(R w ) = 0.028 (0.029) and 0.060 (0.057), respectively. The compounds contain discrete [Cd(NO 3 ) 2 (C 12 H 22 N 6 )] and [Cd(C 12 H 22 N 6 ) 2 ] 2+ complexes, respectively. The Cd atoms are eight-coordinated with four primary and four longer, secondary metal -ligand bonds. In both complexes the hexaamine has an axially symmetrical configuration and acts as a tetradentate ligand. The N03 ligands are aniso-bidentate. Mean bond lengths are (Cd -N) prim 2.308(3), (Cd-N) sec 2.676(3), (Cd-0) prim 2.331(2), (Cd-0) sec 2.593(3) Å for 1, and (Cd-N) prim 2.374 (ligand 1), 2.438 (ligand 2), (Cd-N) sec 2.746 (ligand 1), 2.702 Å (ligand 2) for2. In water the neutral complex 1 dissociates and behaves as an 1:2 electrolyte. 13 C and 113 Cd NMR data and the conductivity of solutions of 2 or 3 in dimethyl sulfoxide indicate a fast but incomplete exchange of the ligands in [Cd(C 12 H 22 N 6 ) 2 ] 2+ by solvent molecules