[μ-N,N′-Bis(2-aminoethyl)ethane-1,2-diamine-κ4 N 1,N 1′:N 2,N 2′]bis{[N,N′-bis(2-aminoethyl)ethane-1,2-diamine-κ4 N,N′,N′′,N′′′]cadmium} tetrakis(perchlorate)

The centrosymmetric dinuclear cadmium title complex, [Cd2(C6H18N4)3](ClO4)4, was obtained by the reaction of N,N′-bis(2-aminoethyl)ethane-1,2-diamine (trien) with Cd(NO3)2·4H2O and sodium perchlorate in methanol. The CdII cation is coordinated by four N atoms of a non-bridging trien ligand and by two N atoms of a bridging trien ligand in a slightly distorted octahedral coordination geometry. The bridging ligand shares another two N atoms with a neighboring symmetry-equivalent CdII cation. The structure displays C—H⋯O and N—H⋯O hydrogen bonding. The perchlorate anion is disordered over two sets of sites in a 0.854 (7): 0.146 (7) ratio.

The centrosymmetric dinuclear cadmium title complex, [Cd 2 (C 6 H 18 N 4 ) 3 ](ClO 4 ) 4 , was obtained by the reaction of N,N 0 -bis(2-aminoethyl)ethane-1,2-diamine (trien) with Cd(NO 3 ) 2 Á4H 2 O and sodium perchlorate in methanol. The Cd II cation is coordinated by four N atoms of a non-bridging trien ligand and by two N atoms of a bridging trien ligand in a slightly distorted octahedral coordination geometry. The bridging ligand shares another two N atoms with a neighboring symmetry-equivalent Cd II cation. The structure displays C-HÁ Á ÁO and N-HÁ Á ÁO hydrogen bonding. The perchlorate anion is disordered over two sets of sites in a 0.854 (7): 0.146 (7) ratio.
The molecular structure of the title complex is shown in Fig. 1. The cadmium(II) centers are six-coordinate by four nitrogen atoms of the non-bridging tetradentate (trien) ligand and two nitrogen atoms of the bridging trien ligand, with a substantial departure from an ideal octahedral geometry [cisoid angles: 73.97 (8)-114.67 (9)°; transoid angles: 141.95 (1)-159.20 (6)°] ( Table 1). The distance between the two cadmium(II) centers of the dinuclear complex is 7.735 Å, which is longer than the corresponding distance in dinickel(II) complex (7.497 Å) of the same ligand (Cai et al. 2001b) due to larger radius of cadmium. Cadmium atoms in the dinuclear complex are related by a 2 fold symmetry operation. Bond distance of Cd-N(trien) are in the range of 2.62 (3)-2.90 (3) Å (Table 1). The structure exhibits disorder of one of the perchlorate anions in two positions with refined occupancy 0.854 (7) and 0.146 (7) for the major and minor componet,respectively. The disorder was described using the rigid body approach. In the title complex the C-H···O and N-H···O hydrogen bonds have been found between the amine nitrogen/carbon donors and perchlorate acceptors ( Fig.2), (Table 2).
Methanol was then carefully added to fill both arms, the tube sealed and the ligand-containing arm immersed in a bath at 333 K, while the other was left at ambient temperature. After one week, colorless crystals were collected in the cooler arm. Then they were filtered off, washed with acetone and diethylether, and air dried. Yield: (53%).

Refinement
All hydrogen atoms were discernible in difference Fourier maps and could be refined to reasonable geometry. According to common practice H atoms bonded to C were kept in ideal positions with C-H = 0.96 Å while positions of other H atoms were refined freely. In both cases U iso (H) was set to 1.2U eq (C,N). Disorder of perchlorate anion was refined using rigid body refinement, with occupancy ratio 0.85:0.15.

Figure 1
The molecular structure of the title compound with 50% probability displacement ellipsoids.