The title complex, [Zn
2(C
13H
19N
2O)
2Cl
2]·2C
3H
6O, resides on a crystallographic inversion center. The two Zn
II centers bridged by the phenoxo groups are in pentacoordinated distorted square-pyramidal coordination environments with an intramolecular Zn
Zn distance of 3.175 (3) Å. The mesocyclic ligand takes a boat–chair conformation and an H atom from the 1,5-diazacyclooctane ring effectively blocks the axial coordination site opposite the Cl ligand to form the ZnN
2O
2Cl geometry. The crystal structure is stabilized by a N—H
O hydrogen bond between the amino group and an acetone molecule.
Supporting information
CCDC reference: 170163
The title complex was synthesized by mixing ZnCl2 (27 mg, 0.2 mmol) and HL (44 mg, 0.2 mmol) in acetone-water. The reaction mixture was filtered, and then
colorless single crystals suitable for X-ray diffraction analysis were
obtained by slow evaporation of the solvent [yield 49 mg (65%)]. FT—IR data
(KBr pellet, cm-1): 3439(b), 3290(m), 2923(w), 2843(w),
1705(s), 1593(s), 1568(m), 1484(versus),
1453(s), 1280(versus), 1271(versus), 1127(m),
1016(s), 881(s), 755(s). Analysis calculated for the
title complex: C 50.81, H 6.66, N 7.41%. Found: C 50.68, H 6.81, N 7.22%.
Hydrogen atoms were placed at idealized positions and were allowed to ride on
the parent atom. The Uiso for the hydrogen atoms were set to be
1.2Ueq for the parent atom.
Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP (Bruker, 1998).
Bis[chloro(1-(2-hydroxybenzyl)-1,5-diazacyclooctane) zinc(II) acetone]
top
Crystal data top
[Zn2(C13H19N2O)2Cl2]·2C3H6O | Z = 1 |
Mr = 756.40 | F(000) = 396 |
Triclinic, P1 | Dx = 1.414 Mg m−3 |
a = 8.8173 (14) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.8916 (17) Å | Cell parameters from 3683 reflections |
c = 11.2986 (17) Å | θ = 2.1–25.0° |
α = 115.254 (3)° | µ = 1.54 mm−1 |
β = 99.964 (3)° | T = 293 K |
γ = 106.135 (3)° | Prism, colorless |
V = 888.0 (2) Å3 | 0.30 × 0.15 × 0.10 mm |
Data collection top
BRUKER SMART 1000 diffractometer | 2718 reflections with I > 2.0σ(I) |
ω scans | Rint = 0.017 |
Absorption correction: multi-scan SAINT (Bruker, 1998) and SADABS (Sheldrick, 1996) | θmax = 25.0° |
Tmin = 0.655, Tmax = 0.861 | h = −10→10 |
3735 measured reflections | k = −12→12 |
3129 independent reflections | l = −11→13 |
Refinement top
Refinement on F2 | w = 1/[σ2(Fo2) + (0.0494P)2 + 0.0111P] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.030 | (Δ/σ)max = 0.005 |
wR(F2) = 0.075 | Δρmax = 0.27 e Å−3 |
S = 1.02 | Δρmin = −0.29 e Å−3 |
3129 reflections | Extinction correction: SHELXL |
199 parameters | Extinction coefficient: none |
H-atom parameters constrained | |
Crystal data top
[Zn2(C13H19N2O)2Cl2]·2C3H6O | γ = 106.135 (3)° |
Mr = 756.40 | V = 888.0 (2) Å3 |
Triclinic, P1 | Z = 1 |
a = 8.8173 (14) Å | Mo Kα radiation |
b = 10.8916 (17) Å | µ = 1.54 mm−1 |
c = 11.2986 (17) Å | T = 293 K |
α = 115.254 (3)° | 0.30 × 0.15 × 0.10 mm |
β = 99.964 (3)° | |
Data collection top
BRUKER SMART 1000 diffractometer | 3129 independent reflections |
Absorption correction: multi-scan SAINT (Bruker, 1998) and SADABS (Sheldrick, 1996) | 2718 reflections with I > 2.0σ(I) |
Tmin = 0.655, Tmax = 0.861 | Rint = 0.017 |
3735 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.030 | 199 parameters |
wR(F2) = 0.075 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.27 e Å−3 |
3129 reflections | Δρmin = −0.29 e Å−3 |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Full-MATRIX |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Zn1 | 0.00206 (3) | 0.53107 (3) | 0.15105 (3) | 0.03281 (11) | |
Cl1 | 0.18300 (9) | 0.45530 (9) | 0.24277 (8) | 0.0604 (2) | |
N1 | 0.0064 (2) | 0.7367 (2) | 0.28977 (19) | 0.0358 (4) | |
H1C | 0.0909 | 0.8064 | 0.2887 | 0.043* | |
N2 | −0.2151 (2) | 0.4500 (2) | 0.21253 (19) | 0.0338 (4) | |
O1 | 0.13497 (19) | 0.61957 (17) | 0.04810 (16) | 0.0385 (4) | |
C1 | −0.1490 (3) | 0.7601 (3) | 0.2500 (3) | 0.0452 (6) | |
H1A | −0.1276 | 0.8249 | 0.2114 | 0.054* | |
H1B | −0.1756 | 0.8097 | 0.3331 | 0.054* | |
C2 | −0.3007 (3) | 0.6176 (3) | 0.1446 (3) | 0.0431 (6) | |
H2A | −0.3957 | 0.6431 | 0.1258 | 0.052* | |
H2B | −0.2776 | 0.5744 | 0.0585 | 0.052* | |
C3 | −0.3514 (3) | 0.5010 (3) | 0.1859 (2) | 0.0400 (6) | |
H3A | −0.3811 | 0.5409 | 0.2690 | 0.048* | |
H3B | −0.4498 | 0.4169 | 0.1124 | 0.048* | |
C4 | −0.1454 (3) | 0.4987 (3) | 0.3624 (2) | 0.0448 (6) | |
H4A | −0.0529 | 0.4688 | 0.3757 | 0.054* | |
H4B | −0.2312 | 0.4486 | 0.3883 | 0.054* | |
C5 | −0.0839 (3) | 0.6646 (3) | 0.4583 (2) | 0.0471 (6) | |
H5A | −0.1790 | 0.6922 | 0.4496 | 0.056* | |
H5B | −0.0429 | 0.6861 | 0.5533 | 0.056* | |
C6 | 0.0531 (3) | 0.7618 (3) | 0.4340 (2) | 0.0447 (6) | |
H6A | 0.0794 | 0.8646 | 0.4988 | 0.054* | |
H6B | 0.1534 | 0.7432 | 0.4532 | 0.054* | |
C7 | −0.2738 (3) | 0.2861 (3) | 0.1307 (2) | 0.0405 (6) | |
H7A | −0.3500 | 0.2426 | 0.1677 | 0.049* | |
H7B | −0.1781 | 0.2597 | 0.1422 | 0.049* | |
C8 | 0.2884 (3) | 0.7278 (2) | 0.1034 (2) | 0.0335 (5) | |
C9 | 0.3813 (3) | 0.7947 (3) | 0.2442 (2) | 0.0398 (6) | |
H9A | 0.3370 | 0.7600 | 0.2982 | 0.048* | |
C10 | 0.5366 (3) | 0.9104 (3) | 0.3058 (3) | 0.0439 (6) | |
H10A | 0.5937 | 0.9541 | 0.4002 | 0.053* | |
C11 | 0.6063 (3) | 0.9608 (3) | 0.2262 (3) | 0.0451 (6) | |
H11A | 0.7103 | 1.0391 | 0.2664 | 0.054* | |
C12 | 0.5194 (3) | 0.8930 (3) | 0.0862 (3) | 0.0433 (6) | |
H12A | 0.5684 | 0.9251 | 0.0325 | 0.052* | |
C13 | 0.3613 (3) | 0.7787 (2) | 0.0223 (2) | 0.0351 (5) | |
C14 | 0.4178 (5) | 0.2542 (4) | 0.3898 (5) | 0.1026 (15) | |
H14A | 0.4629 | 0.2777 | 0.4841 | 0.154* | |
H14B | 0.3936 | 0.3346 | 0.3891 | 0.154* | |
H14C | 0.4982 | 0.2382 | 0.3438 | 0.154* | |
C15 | 0.2624 (5) | 0.1190 (3) | 0.3168 (4) | 0.0653 (9) | |
C16 | 0.1757 (7) | 0.0649 (5) | 0.1698 (5) | 0.1132 (16) | |
H16A | 0.0775 | −0.0234 | 0.1339 | 0.170* | |
H16B | 0.2494 | 0.0437 | 0.1178 | 0.170* | |
H16C | 0.1435 | 0.1391 | 0.1619 | 0.170* | |
O2 | 0.2075 (3) | 0.0548 (2) | 0.3747 (3) | 0.0780 (7) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Zn1 | 0.03135 (16) | 0.03404 (17) | 0.02656 (16) | 0.01193 (12) | 0.00601 (11) | 0.01181 (12) |
Cl1 | 0.0504 (4) | 0.0661 (5) | 0.0723 (5) | 0.0329 (4) | 0.0110 (3) | 0.0386 (4) |
N1 | 0.0335 (11) | 0.0322 (10) | 0.0322 (10) | 0.0095 (9) | 0.0055 (8) | 0.0124 (9) |
N2 | 0.0381 (11) | 0.0306 (10) | 0.0266 (10) | 0.0106 (9) | 0.0077 (8) | 0.0124 (8) |
O1 | 0.0312 (9) | 0.0386 (9) | 0.0284 (9) | 0.0032 (7) | 0.0061 (7) | 0.0103 (7) |
C1 | 0.0467 (15) | 0.0364 (13) | 0.0475 (15) | 0.0201 (12) | 0.0089 (12) | 0.0171 (12) |
C2 | 0.0397 (14) | 0.0427 (14) | 0.0409 (14) | 0.0218 (12) | 0.0045 (11) | 0.0160 (12) |
C3 | 0.0311 (12) | 0.0407 (13) | 0.0344 (13) | 0.0111 (11) | 0.0071 (10) | 0.0107 (11) |
C4 | 0.0485 (16) | 0.0497 (15) | 0.0318 (13) | 0.0127 (13) | 0.0108 (11) | 0.0219 (12) |
C5 | 0.0524 (16) | 0.0514 (16) | 0.0239 (12) | 0.0150 (13) | 0.0086 (11) | 0.0127 (12) |
C6 | 0.0439 (15) | 0.0404 (14) | 0.0295 (13) | 0.0125 (12) | 0.0029 (11) | 0.0067 (11) |
C7 | 0.0438 (14) | 0.0335 (13) | 0.0369 (14) | 0.0076 (11) | 0.0079 (11) | 0.0183 (11) |
C8 | 0.0301 (12) | 0.0289 (11) | 0.0325 (12) | 0.0102 (10) | 0.0084 (9) | 0.0097 (10) |
C9 | 0.0359 (13) | 0.0418 (14) | 0.0324 (13) | 0.0125 (11) | 0.0106 (10) | 0.0131 (11) |
C10 | 0.0362 (14) | 0.0418 (14) | 0.0359 (14) | 0.0125 (11) | 0.0041 (11) | 0.0095 (11) |
C11 | 0.0344 (14) | 0.0329 (13) | 0.0470 (16) | 0.0039 (11) | 0.0020 (11) | 0.0126 (12) |
C12 | 0.0424 (15) | 0.0337 (13) | 0.0470 (15) | 0.0084 (11) | 0.0115 (12) | 0.0199 (12) |
C13 | 0.0365 (13) | 0.0274 (11) | 0.0354 (13) | 0.0108 (10) | 0.0075 (10) | 0.0136 (10) |
C14 | 0.083 (3) | 0.080 (3) | 0.153 (4) | 0.028 (2) | 0.064 (3) | 0.058 (3) |
C15 | 0.081 (2) | 0.0511 (18) | 0.087 (2) | 0.0413 (18) | 0.051 (2) | 0.0363 (18) |
C16 | 0.168 (5) | 0.105 (3) | 0.093 (3) | 0.071 (4) | 0.057 (3) | 0.056 (3) |
O2 | 0.0965 (19) | 0.0525 (13) | 0.0791 (16) | 0.0185 (13) | 0.0360 (14) | 0.0324 (13) |
Geometric parameters (Å, º) top
Zn1—O1i | 2.0056 (15) | C4—C5 | 1.522 (4) |
Zn1—N1 | 2.0998 (19) | C5—C6 | 1.519 (4) |
Zn1—O1 | 2.1109 (16) | C7—C13i | 1.509 (3) |
Zn1—N2 | 2.2298 (19) | C8—C9 | 1.400 (3) |
Zn1—Cl1 | 2.2781 (7) | C8—C13 | 1.414 (3) |
N1—C6 | 1.491 (3) | C9—C10 | 1.381 (3) |
N1—C1 | 1.492 (3) | C10—C11 | 1.384 (4) |
N2—C7 | 1.491 (3) | C11—C12 | 1.380 (4) |
N2—C4 | 1.489 (3) | C12—C13 | 1.391 (3) |
N2—C3 | 1.494 (3) | C13—C7i | 1.509 (3) |
O1—C8 | 1.343 (3) | C14—C15 | 1.476 (5) |
O1—Zn1i | 2.0056 (15) | C15—O2 | 1.210 (4) |
C1—C2 | 1.528 (3) | C15—C16 | 1.471 (5) |
C2—C3 | 1.514 (3) | | |
| | | |
O1i—Zn1—N1 | 133.30 (7) | Zn1i—O1—Zn1 | 100.92 (7) |
O1i—Zn1—O1 | 79.08 (7) | N1—C1—C2 | 113.82 (19) |
N1—Zn1—O1 | 92.62 (7) | C3—C2—C1 | 116.4 (2) |
O1i—Zn1—N2 | 89.13 (7) | N2—C3—C2 | 112.45 (19) |
N1—Zn1—N2 | 81.63 (7) | N2—C4—C5 | 113.8 (2) |
O1—Zn1—N2 | 157.62 (7) | C6—C5—C4 | 116.3 (2) |
O1i—Zn1—Cl1 | 111.63 (5) | N1—C6—C5 | 113.4 (2) |
N1—Zn1—Cl1 | 115.04 (6) | N2—C7—C13i | 113.62 (19) |
O1—Zn1—Cl1 | 102.18 (5) | O1—C8—C9 | 120.9 (2) |
N2—Zn1—Cl1 | 99.84 (5) | O1—C8—C13 | 121.4 (2) |
C6—N1—C1 | 112.69 (19) | C9—C8—C13 | 117.8 (2) |
C6—N1—Zn1 | 109.81 (14) | C10—C9—C8 | 122.4 (2) |
C1—N1—Zn1 | 114.51 (14) | C11—C10—C9 | 119.5 (2) |
C7—N2—C4 | 108.39 (18) | C12—C11—C10 | 119.0 (2) |
C7—N2—C3 | 112.05 (18) | C11—C12—C13 | 122.6 (2) |
C4—N2—C3 | 111.66 (18) | C12—C13—C8 | 118.7 (2) |
C7—N2—Zn1 | 103.64 (14) | C12—C13—C7i | 118.9 (2) |
C4—N2—Zn1 | 106.29 (14) | C8—C13—C7i | 122.5 (2) |
C3—N2—Zn1 | 114.28 (14) | O2—C15—C16 | 121.0 (4) |
C8—O1—Zn1i | 130.14 (14) | O2—C15—C14 | 121.7 (4) |
C8—O1—Zn1 | 127.40 (14) | C16—C15—C14 | 117.3 (4) |
Symmetry code: (i) −x, −y+1, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1C···O2ii | 0.91 | 2.28 | 3.038 (3) | 141 |
Symmetry code: (ii) x, y+1, z. |
Experimental details
Crystal data |
Chemical formula | [Zn2(C13H19N2O)2Cl2]·2C3H6O |
Mr | 756.40 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 8.8173 (14), 10.8916 (17), 11.2986 (17) |
α, β, γ (°) | 115.254 (3), 99.964 (3), 106.135 (3) |
V (Å3) | 888.0 (2) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 1.54 |
Crystal size (mm) | 0.30 × 0.15 × 0.10 |
|
Data collection |
Diffractometer | BRUKER SMART 1000 diffractometer |
Absorption correction | Multi-scan SAINT (Bruker, 1998) and SADABS (Sheldrick, 1996) |
Tmin, Tmax | 0.655, 0.861 |
No. of measured, independent and observed [I > 2.0σ(I)] reflections | 3735, 3129, 2718 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.030, 0.075, 1.02 |
No. of reflections | 3129 |
No. of parameters | 199 |
No. of restraints | ? |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.29 |
Selected geometric parameters (Å, º) topZn1—O1i | 2.0056 (15) | Zn1—N2 | 2.2298 (19) |
Zn1—N1 | 2.0998 (19) | Zn1—Cl1 | 2.2781 (7) |
Zn1—O1 | 2.1109 (16) | | |
| | | |
O1i—Zn1—N1 | 133.30 (7) | O1i—Zn1—Cl1 | 111.63 (5) |
O1i—Zn1—O1 | 79.08 (7) | N1—Zn1—Cl1 | 115.04 (6) |
N1—Zn1—O1 | 92.62 (7) | O1—Zn1—Cl1 | 102.18 (5) |
O1i—Zn1—N2 | 89.13 (7) | N2—Zn1—Cl1 | 99.84 (5) |
N1—Zn1—N2 | 81.63 (7) | Zn1i—O1—Zn1 | 100.92 (7) |
O1—Zn1—N2 | 157.62 (7) | | |
Symmetry code: (i) −x, −y+1, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1C···O2ii | .910 | 2.278 | 3.038 (3) | 140.85 |
Symmetry code: (ii) x, y+1, z. |
Zinc, the second most abundant transition metal in biology, functions as the active site of hydrolytic enzymes, such as carboxypetidase and carbonic anhydrase where it is in a hard donor coordination environment of nitrogen and oxygen (Lipscomb & Strater, 1996). There are numerous structural studies on zinc-containing complexes in which the zinc atom generally is found to assume a tetrahedral geometry. Corresponding studies on the less common pentacoordinated zinc complexes are relatively less explored (Yam et al., 2000). Geometries other than that of four coordinate are interesting in view of the possibility of the zinc adopting a as penta-, tri- or perhaps even hexacoordinated structures in the functional states of the biological system (Brand et al., 1996). As most of the zinc complexes with unusual coordination numbers were discovered more by accident than by design or with special ligand systems. The factors governing pentacoordination are still largely unknown (Zhang et al., 1991). \sch
1,5-Diazacyclooctane (DACO) is a typical example of diazamesocycles, which usually shows an interesting `boat/chair' conformation when binding to metal ions, and such a conformation blocks the sixth coordination from the apical site to form a pentacoordination complex (Musker, 1992; Grapperhaus & Darensbourg, 1998). In our ongoing studies of 1,5-diazacyclooctane ligands we have obtained a series of pentacoordinate complexes with a variety of metals: CuII (Bu et al., 2000), CoII (Du, Shang et al., 2000), NiII (Bu et al., 2001) and CdII (Du, Weng et al., 2000). However, the crystal structure of the zinc(II) complexes of DACO ligands are still undetermined. In this paper, we report the crystal structure of a novel phenoxo-bridged binuclear zinc(II) complex with a distorted square-pyramidal ZnN2O2Cl geometry of 1-(2-hydroxybenzyl)-1,5-diazacyclooctane, (I) (Chart I). \sch
The structure of (I) comprises a neutral binuclear entity and an uncoordinated acetone molecule (Fig. 1). Each molecule results from the pairing of two mononuclear units related by a crystallographic center of symmetry. Each ZnII center in this complex is bound by five donor atoms occupying the vertices of a distorted square-pyramidal coordination environment with τ = 0.27 (Addison et al., 1984), which is used to describe the degree of distortion for pentacoordinated complexes (τ = 0 for an ideal square-pyramid, and τ = 1 for an ideal trigonal bipyramid). Two bridging oxygen atoms of the deprotonated pendant phenol groups and two nitrogen donors of the DACO ring of the ligand comprise the basal plane, and each axial coordination site is occupied by a chloride anion. The ZnII ion deviates from the basal mean equatorial plane of the square-pyramid towards the apical Cl1 by ca 0.61 Å.
The two ZnII centers are equivalently bridged by two phenoxo oxygen anions of the parallel phenol rings, which are bound asymmetrically to ZnII at slightly different distances of 2.0056 (15) versus 2.1109 (16) Å, respectively (Table 1). The Zn—O—Zn bridging angle is 100.80 (12)° and the two ZnII centers are separated by 3.175 (3) Å.
The ligand adopts a `boat/chair' conformation and gives rise with each ZnII center to two five-membered chelate rings, which enhance the coordination ability to ZnII. The central methylene C—H group of the boat form in DACO shields the ZnII center with an H2b—Zn1 distance of 2.749 (3) Å, which effectively blocks the sixth coordination position to give this novel pentacoordinated ZnII complex.
In this structure, each amino group of the ligand forms an N—H···O hydrogen bond with an acetone molecule. The N···O separation is 3.038 (3) Å with an H···O separation 2.278 of Å and bond angle of 141°, which are in the normal range of weak interactions (Sasada, 1984).