Rerefinement of (μ-1,7,11,17-tetraoxa-2,6,12,16-tetra­aza­cyclo­ei­cosane-κ⁴N¹,N¹⁷:N⁷,N¹¹)­bis­[di­chlorozinc(II)]

This rerefinement of the title compound, [Zn₂Cl₄(C₁₂H₂₈­N₄O₄)], based on the original intensity data, differs from the original only in the exchange of the NH and O moieties of the oxa­aza-macrocycle, resulting in a dramatic improvement in the R factors and the anisotropic displacement parameters associated with the N and O atoms. The tetrahedral coordination of Zn involves Cl at 2.2144 (6) and 2.2279 (6) Å, but now N rather than O at 2.0563 (18) and 2.0934 (17) Å, in keeping with the usual arrangement for zinc complexes of this type. The revised model permits satisfactory N—H...Cl hydrogen bonds which the original did not. A crystallographic twofold axis passes through the centroid of the mol­ecule perpendicular to its least-squares plane.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.031
• wR factor = 0.084
• Data-to-parameter ratio = 20.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level A:



DIFF_020  Alert A _diffrn_standards_interval_count and
          _diffrn_standards_interval_time are missing. Number of measurements
          between standards or time (min) between standards.


 1 Alert Level A = Potentially serious problem

 0 Alert Level B = Potential problem

 0 Alert Level C = Please check

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Computing details

Data collection: MADNES (Pflugrath & Messerschmidt, 1989); cell refinement: MADNES; data reduction: ABSMAD (Karaulov, 1992); program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

(µ-1,7,11,17-tetraoxa-2,6,12,16-tetraazacycloeicosane- κ⁴N¹,N¹⁷:N⁷,N¹¹)bis[dichlorozinc(II)]

Crystal data

[Zn2Cl4(C12H28N4O4)]	Dx = 1.727 Mg m^−3
Mr = 564.92	Melting point: 428 (dec.) K
Monoclinic, I2/a	Mo Kα radiation, λ = 0.71073 Å
a = 16.4925 (4) Å	Cell parameters from 12531 reflections
b = 7.2697 (2) Å	θ = 2.6–27.5°
c = 19.2129 (6) Å	µ = 2.72 mm^−1
β = 109.4120 (18)°	T = 150 K
V = 2172.59 (10) Å^3	Block, colourless
Z = 4	0.20 × 0.15 × 0.15 mm
F(000) = 1152

Data collection

Delft Instruments FAST diffractometer	2470 independent reflections
Radiation source: fine-focus sealed tube	2096 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.043
φ scans	θmax = 27.5°, θmin = 2.6°
Absorption correction: part of the refinement model (ΔF) (DIFABS; Walker & Stuart, 1983)	h = −20→21
Tmin = 0.589, Tmax = 0.665	k = −8→9
12531 measured reflections	l = −24→20

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.031	H-atom parameters constrained
wR(F^2) = 0.084	w = 1/[σ^2(Fo^2) + (0.0469P)^2 + 1.0443P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max = 0.001
2470 reflections	Δρmax = 0.47 e Å^−3
119 parameters	Δρmin = −0.48 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: heavy-atom method	Extinction coefficient: 0.0027 (3)

Special details

Experimental. General cell determination and refinement and data collection strategy given by Darr et al., (1993). [Darr, J·A, Drake, S·R., Hursthouse, M·B. & Malik, K·M·A. (1993). Inorg. Chem. 32, 5704–5708.]

In this particular case the intensity data was collected and indexed on the basis of a primitive triclinic cell and reindexed with the row-wise transformation matrix 0 - 1 1; -1 0 0; 1 - 1 -1 for conformity with the I-centred monoclinic cell used in the solution and refinement of the structure.

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. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Anisotropic displacement parameters refined for all non-H atoms. H atoms in calculated positions and refined with a riding model.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Zn1	0.138184 (15)	0.89385 (3)	0.285513 (14)	0.03322 (13)
Cl1	0.14071 (4)	0.59248 (7)	0.26963 (3)	0.03897 (16)
Cl2	0.09477 (4)	1.06026 (9)	0.18231 (3)	0.04809 (18)
O1	0.05409 (10)	0.9352 (2)	0.41059 (9)	0.0401 (4)
O2	0.28973 (9)	0.8821 (2)	0.41422 (9)	0.0365 (4)
N1	0.06264 (11)	1.0067 (2)	0.34338 (10)	0.0337 (4)
H1	0.0070	1.0094	0.3097	0.040*
N2	0.25399 (11)	1.0002 (3)	0.35086 (10)	0.0349 (4)
H2	0.2912	0.9978	0.3236	0.042*
C1	0.08938 (15)	0.7196 (3)	0.50694 (13)	0.0413 (5)
H1A	0.0274	0.6962	0.4971	0.050*
H1B	0.1205	0.6034	0.5252	0.050*
C2	0.10231 (14)	0.7704 (3)	0.43507 (13)	0.0348 (5)
H2A	0.1640	0.7915	0.4428	0.042*
H2B	0.0811	0.6710	0.3983	0.042*
C3	0.08763 (14)	1.2010 (3)	0.35820 (14)	0.0404 (5)
H3A	0.0488	1.2610	0.3810	0.048*
H3B	0.0806	1.2641	0.3109	0.048*
C4	0.17960 (15)	1.2230 (3)	0.40880 (15)	0.0418 (5)
H4A	0.1895	1.1360	0.4504	0.050*
H4B	0.1864	1.3489	0.4296	0.050*
C5	0.24924 (14)	1.1920 (3)	0.37434 (15)	0.0419 (5)
H5A	0.2382	1.2738	0.3310	0.050*
H5B	0.3055	1.2268	0.4105	0.050*
C6	0.38077 (14)	0.8625 (4)	0.43278 (13)	0.0403 (5)
H6A	0.4096	0.9815	0.4502	0.048*
H6B	0.3951	0.8231	0.3889	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.03275 (18)	0.03814 (19)	0.02704 (19)	0.00302 (9)	0.00759 (12)	0.00176 (9)
Cl1	0.0438 (3)	0.0369 (3)	0.0375 (3)	0.0023 (2)	0.0151 (3)	0.0007 (2)
Cl2	0.0454 (3)	0.0618 (4)	0.0335 (3)	0.0024 (3)	0.0084 (3)	0.0151 (3)
O1	0.0423 (9)	0.0496 (9)	0.0355 (9)	0.0061 (7)	0.0223 (8)	0.0074 (7)
O2	0.0255 (7)	0.0502 (9)	0.0325 (9)	0.0048 (6)	0.0077 (6)	0.0129 (6)
N1	0.0296 (9)	0.0405 (10)	0.0303 (10)	0.0039 (7)	0.0093 (7)	0.0059 (8)
N2	0.0280 (9)	0.0472 (11)	0.0294 (10)	0.0044 (8)	0.0095 (7)	0.0085 (8)
C1	0.0382 (12)	0.0504 (13)	0.0329 (13)	−0.0150 (10)	0.0088 (10)	0.0029 (10)
C2	0.0342 (11)	0.0362 (11)	0.0339 (12)	−0.0032 (8)	0.0112 (9)	−0.0004 (9)
C3	0.0386 (12)	0.0388 (12)	0.0455 (14)	0.0085 (9)	0.0162 (11)	0.0049 (10)
C4	0.0412 (13)	0.0368 (12)	0.0453 (14)	−0.0006 (9)	0.0114 (11)	−0.0031 (10)
C5	0.0345 (11)	0.0390 (12)	0.0501 (15)	−0.0042 (9)	0.0114 (11)	0.0071 (11)
C6	0.0265 (11)	0.0638 (14)	0.0316 (13)	0.0076 (10)	0.0109 (9)	0.0039 (10)

Geometric parameters (Å, º)

Zn1—N2	2.0563 (18)	C1—H1B	0.990
Zn1—N1	2.0934 (17)	C2—H2A	0.990
Zn1—Cl1	2.2144 (6)	C2—H2B	0.990
Zn1—Cl2	2.2279 (6)	C3—C4	1.514 (3)
O1—C2	1.429 (3)	C3—H3A	0.990
O1—N1	1.442 (2)	C3—H3B	0.990
O2—C6	1.430 (3)	C4—C5	1.521 (3)
O2—N2	1.446 (2)	C4—H4A	0.990
N1—C3	1.472 (3)	C4—H4B	0.990
N1—H1	0.930	C5—H5A	0.990
N2—C5	1.475 (3)	C5—H5B	0.990
N2—H2	0.930	C6—C1^i	1.511 (3)
C1—C6^i	1.511 (3)	C6—H6A	0.990
C1—C2	1.511 (3)	C6—H6B	0.990
C1—H1A	0.990
N2—Zn1—N1	97.14 (7)	C1—C2—H2A	110.6
N2—Zn1—Cl1	113.58 (5)	O1—C2—H2B	110.6
N1—Zn1—Cl1	120.18 (5)	C1—C2—H2B	110.6
N2—Zn1—Cl2	107.32 (5)	H2A—C2—H2B	108.7
N1—Zn1—Cl2	100.83 (5)	N1—C3—C4	112.45 (17)
Cl1—Zn1—Cl2	115.45 (3)	N1—C3—H3A	109.1
C2—O1—N1	112.82 (15)	C4—C3—H3A	109.1
C6—O2—N2	111.67 (15)	N1—C3—H3B	109.1
O1—N1—C3	106.09 (16)	C4—C3—H3B	109.1
O1—N1—Zn1	125.94 (12)	H3A—C3—H3B	107.8
C3—N1—Zn1	107.51 (12)	C3—C4—C5	116.4 (2)
O1—N1—H1	105.2	C3—C4—H4A	108.2
C3—N1—H1	105.2	C5—C4—H4A	108.2
Zn1—N1—H1	105.2	C3—C4—H4B	108.2
O2—N2—C5	110.62 (17)	C5—C4—H4B	108.2
O2—N2—Zn1	109.07 (11)	H4A—C4—H4B	107.3
C5—N2—Zn1	114.14 (13)	N2—C5—C4	113.43 (17)
O2—N2—H2	107.6	N2—C5—H5A	108.9
C5—N2—H2	107.6	C4—C5—H5A	108.9
Zn1—N2—H2	107.6	N2—C5—H5B	108.9
C6^i—C1—C2	115.06 (18)	C4—C5—H5B	108.9
C6^i—C1—H1A	108.5	H5A—C5—H5B	107.7
C2—C1—H1A	108.5	O2—C6—C1^i	107.87 (18)
C6^i—C1—H1B	108.5	O2—C6—H6A	110.1
C2—C1—H1B	108.5	C1^i—C6—H6A	110.1
H1A—C1—H1B	107.5	O2—C6—H6B	110.1
O1—C2—C1	105.86 (17)	C1^i—C6—H6B	110.1
O1—C2—H2A	110.6	H6A—C6—H6B	108.4
C2—O1—N1—C3	−127.89 (18)	N1—Zn1—N2—C5	−40.83 (15)
C2—O1—N1—Zn1	−1.3 (2)	Cl1—Zn1—N2—C5	−168.24 (13)
N2—Zn1—N1—O1	−80.20 (17)	Cl2—Zn1—N2—C5	62.90 (15)
Cl1—Zn1—N1—O1	42.43 (18)	N1—O1—C2—C1	177.58 (17)
Cl2—Zn1—N1—O1	170.56 (15)	C6^i—C1—C2—O1	−60.0 (3)
N2—Zn1—N1—C3	45.79 (14)	O1—N1—C3—C4	72.5 (2)
Cl1—Zn1—N1—C3	168.42 (12)	Zn1—N1—C3—C4	−64.5 (2)
Cl2—Zn1—N1—C3	−63.45 (13)	N1—C3—C4—C5	76.5 (2)
C6—O2—N2—C5	−93.0 (2)	O2—N2—C5—C4	−72.2 (2)
C6—O2—N2—Zn1	140.65 (15)	Zn1—N2—C5—C4	51.3 (2)
N1—Zn1—N2—O2	83.45 (12)	C3—C4—C5—N2	−66.4 (3)
Cl1—Zn1—N2—O2	−43.96 (13)	N2—O2—C6—C1^i	−173.15 (18)
Cl2—Zn1—N2—O2	−172.81 (10)	C2—C1—C6^i—O2^i	−63.7 (3)

Symmetry code: (i) −x+1/2, y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Cl1^ii	0.93	2.48	3.3926 (19)	166
N2—H2···Cl1^iii	0.93	2.50	3.3914 (18)	161

Symmetry codes: (ii) −x, y+1/2, −z+1/2; (iii) −x+1/2, −y+3/2, −z+1/2.