Triaqua­(1,4,7-triaza­cyclo­nonane-κ3 N 1,N 4,N 7)nickel(II) bromide nitrate

Changchun Wen; Jianqi Lu; Zhong Zhang

doi:10.1107/S160053681001620X

. 2010 May 8;66(Pt 6):m624–m625. doi: 10.1107/S160053681001620X

Triaqua(1,4,7-triazacyclononane-κ³ N ¹,N ⁴,N ⁷)nickel(II) bromide nitrate

Changchun Wen ^a, Jianqi Lu ^a, Zhong Zhang ^a,^*

PMCID: PMC2979567 PMID: 21579281

Abstract

In the title half-sandwich compound, [Ni(C₆H₁₅N₃)(H₂O)₃]Br(NO₃), the central Ni^II ion, lying on a threefold rotation axis, is six-coordinated by three amine N atoms from the face-capping triaza macrocycle and three water O atoms in a slightly distorted octahedral geometry. In the crystal, O—H⋯O hydrogen bonding and weak O—H⋯Br interactions associate the Ni^II cations and the counter-ions into a three-dimensional supramolecular network.

Related literature

For the preparation of 1,4,7-triazacyclononane trihydrobromide, see: Koyama & Yoshino (1972 ▶). For the applications of metal complexes containing 1,4,7-triazacyclononane as small-molecule models of metalloenzymes and metalloproteins and as molecule-based magnets, see: Berseth et al. (2000 ▶); Chaudhury et al. (1985 ▶); Cheng et al. (2004 ▶); Deal et al. (1996 ▶); Hegg & Burstyn (1995 ▶); Hegg et al. (1997 ▶); Lin et al. (2001 ▶); Poganiuch et al. (1991 ▶); Williams et al. (1999 ▶). For related Ni^II complexes with 1,4,7-triazacyclononane, see: Bencini et al. (1990 ▶); Stranger et al. (1992 ▶); Wang et al. (2003 ▶, 2005 ▶); Zompa & Margulis (1978 ▶).

Experimental

Crystal data

[Ni(C₆H₁₅N₃)(H₂O)₃]Br(NO₃)
M _r = 383.89
Cubic,
a = 11.300 (1) Å
V = 1442.9 (3) Å³
Z = 4
Mo Kα radiation
μ = 4.14 mm⁻¹
T = 298 K
0.29 × 0.27 × 0.18 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1998 ▶) T _min = 0.320, T _max = 0.480
15223 measured reflections
1110 independent reflections
985 reflections with I > 2σ(I)
R _int = 0.080

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.072
S = 1.03
1110 reflections
61 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.47 e Å⁻³
Absolute structure: Flack (1983 ▶), 475 Friedel pairs
Flack parameter: 0.01 (3)

Data collection: APEX2 (Bruker, 2002 ▶); cell refinement: SAINT (Bruker, 2002 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681001620X/pb2027sup1.cif

e-66-0m624-sup1.cif^{(14.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053681001620X/pb2027Isup2.hkl

e-66-0m624-Isup2.hkl^{(55.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H4A⋯O2ⁱ	0.84 (4)	1.95 (5)	2.776 (5)	162 (4)
O1—H4B⋯Br1ⁱⁱ	0.85 (5)	2.48 (5)	3.312 (3)	167 (4)

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors are grateful for financial support from the Guangxi Science Foundation (grant No. 0832023) and the Scientific Research Foundation of Guangxi Normal University.

supplementary crystallographic information

Comment

The coordination chemistry of 1,4,7–triazacyclononane (TACN) has been extensively studied for its applications in the simulation of metalloenzymes and metalloproteins (Chaudhury et al., 1985; Deal et al., 1996; Hegg & Burstyn, 1995; Hegg et al., 1997; Lin et al., 2001; Williams et al., 1999) as well as in constructing molecule–based magnetic materials (Berseth et al., 2000; Cheng et al., 2004; Poganiuch et al., 1991). In general, TACN ligand can form stable sandwich complexes with many transition metals (Stranger et al., 1992; Zompa & Margulis, 1978) or functions as a terminal chelator for the assembly of binuclear/polynuclear species and coordination polymers supported by bridging ligands (Bencini et al., 1990; Wang et al., 2005; Wang et al., 2003). In this paper, a half–sandwich type Ni^II complex with TACN has been synthesized and characterized.

In the selected crystal, the title compound (I) crystallizes in a chiral space group P2₁3 and Flack parameter of 0.01 (3) indicates that a spontaneous resolution has been achieved during crystallization. As depicted in Fig. 1, the Ni^II center in the complex cation lies on a three–fold rotation axis and three amine N atoms from facially coordinated TACN and three water molecules complete the slightly distorted octahedral arrangement. Upon coordination, three five–membered Ni—N—C—C—N chelating rings subtended at metal center adopt (λλλ) conformation, which is the source of the chirality of the crystal. Ni—N [2.091 (3) Å] and Ni—O [2.089 (3) Å] bond lengths are both in the normal ranges, meanwhile N—Ni—N bond angle is smaller than that of O—Ni—O due to the small size of TACN ring. Counter–ions NO₃^- and Br^- interconnect neighbouring cations by O—H···O hydrogen bond and O—H···Br^- weak interaction (Table 1) into three–dimensional supramolecular network (Fig. 2).

Experimental

1,4,7–Triazacyclononane trihydrobromide (TACN^.3HBr) was prepared by following a modified published method (Koyama & Yoshino, 1972).

To a solution of 0.074 g (0.02 mmol) of TACN^.3HBr in water (10 ml), 0.1 M NaOH was added to adjust the pH to 6. Then aqueous solution (5 ml) of 0.058 g (0.02 mmol) of Ni(NO₃)₂^.6H₂0 was added and the resulting mixture was stirred under reflux for 6 h. After cooling, the mixture was filtered, and the filtrate was allowed to standing at ambient temperature. Plate–like green single crystals suitable for X–ray crystallographic analysis were collected by slow evaporation of the filtrate within two months.