Bis{2-[bis­(2-hy­droxy­eth­yl)amino]­acetato-κ³O,N,O′}zinc(II)

In the crystal structure of the zinc(II) complex of bicine, [Zn(C₆H₁₂NO₄)₂], the deprotonated amino acid O,N,O′-chelates to the metal atom through a carboxyl­ate O atom, a hy­droxy O atom and the N atom, the three atoms occupying fac positions of the distorted octa­hedron surrounding the metal atom. The metal atom lies on a center of inversion. The uncoordinated carboxyl­ate O atom is hydrogen bonded to the hy­droxy groups of adjacent mol­ecules, these two hydrogen bonds leading to the formation of a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.021
• wR factor = 0.062
• Data-to-parameter ratio = 15.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT934_ALERT_3_B Number of (Iobs-Icalc)/SigmaW .gt. 10 Outliers .          2

Alert level C
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Zn1    --  O1      ..       5.21 su
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Zn1    --  O3      ..       5.08 su
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600          2
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600          2

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2
PLAT793_ALERT_4_G The Model has Chirality at N1      (Verify) ....          R
PLAT794_ALERT_5_G Note: Tentative Bond Valency for Zn1     .......       2.05

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

In the crystal structure of the cobalt(II) derivative of bicine, the deprotonated aminoacid N,O,O'-chelates to the metal atom through the nitrogen, carboxyl oxygen and hydroxyl oxygen atoms, the three atoms occupying fac positions of the octahedron (Zhao & Liu, 2010). The present zinc analog (Scheme I, Fig. 1) is isostructural. The double-bond carboxyl oxygen atom is hydrogen-bond acceptor to the coordinated as well as the free hydroxyl unit of adjacent molecules, these two hydrogen bonds leading to the formation of a three-dimensional network (Table 1).

Related literature

For the isostructural cobalt(II) analog, see: Zhao & Liu (2010).

S2. Experimental

N,N-Bis(2-hydroxyethyl)glycine (0.94 g, 5.7 mmol) and zinc carbonate (0.36 g, 2.8 mmol) were heated in a 1:1 water:DMSO mixture (100 ml) for 1 h. The solution was filtered; colorless crystals were obtained upon slow evaporation of the filtrate.

S3. Refinement

Carbon-bound H-atoms were placed in calculated positions (C—H 0.99 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U(C).

The hydroxy H-atoms were located in a difference Fourier map, and were refined with the O–H distance restrained to 0.84±0.01 Å; its temperature factor was refined.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

Fig. 1. Thermal ellipsoid plot (Barbour, 2001) of Zn(C6H12NO4)2 at the 70% probability level; hydrogen atoms are drawn as spheres of arbitrary radius.

Bis{2-[bis(2-hydroxyethyl)amino]acetato- κ³O,N,O'}zinc(II)

Crystal data

[Zn(C6H12NO4)2]	F(000) = 408
Mr = 389.70	Dx = 1.676 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4608 reflections
a = 9.7863 (7) Å	θ = 2.2–28.3°
b = 11.3715 (8) Å	µ = 1.64 mm^−1
c = 7.3462 (5) Å	T = 100 K
β = 109.1495 (8)°	Block, colorless
V = 772.28 (9) Å^3	0.25 × 0.20 × 0.15 mm
Z = 2

Data collection

Bruker SMART APEX diffractometer	1773 independent reflections
Radiation source: fine-focus sealed tube	1634 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.026
ω scans	θmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→12
Tmin = 0.685, Tmax = 0.792	k = −14→14
7174 measured reflections	l = −9→9

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.062	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0283P)^2 + 0.4612P] where P = (Fo^2 + 2Fc^2)/3
1773 reflections	(Δ/σ)max = 0.001
114 parameters	Δρmax = 0.43 e Å^−3
2 restraints	Δρmin = −0.35 e Å^−3

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

	x	y	z	Uiso*/Ueq
Zn1	0.5000	0.5000	0.5000	0.00889 (9)
O1	0.45689 (11)	0.33271 (9)	0.56937 (15)	0.0132 (2)
O2	0.28013 (11)	0.21247 (9)	0.57458 (17)	0.0167 (2)
O3	0.51490 (11)	0.55292 (9)	0.78390 (15)	0.0129 (2)
H3	0.564 (2)	0.6126 (14)	0.831 (3)	0.030 (6)*
O4	0.00548 (11)	0.66106 (11)	0.01696 (15)	0.0160 (2)
H4	−0.0808 (12)	0.678 (2)	−0.009 (3)	0.040 (7)*
N1	0.27253 (13)	0.52389 (11)	0.44766 (18)	0.0095 (2)
C1	0.32624 (16)	0.31061 (13)	0.5430 (2)	0.0116 (3)
C2	0.21180 (15)	0.40649 (12)	0.4649 (2)	0.0114 (3)
H2A	0.1466	0.3821	0.3363	0.014*
H2B	0.1528	0.4130	0.5511	0.014*
C3	0.26823 (16)	0.60594 (13)	0.6035 (2)	0.0128 (3)
H3A	0.1690	0.6082	0.6106	0.015*
H3B	0.2935	0.6862	0.5732	0.015*
C4	0.37309 (16)	0.56760 (14)	0.7966 (2)	0.0141 (3)
H4A	0.3757	0.6275	0.8955	0.017*
H4B	0.3400	0.4925	0.8360	0.017*
C5	0.20539 (15)	0.57679 (13)	0.2541 (2)	0.0114 (3)
H5A	0.2129	0.5197	0.1561	0.014*
H5B	0.2620	0.6472	0.2442	0.014*
C6	0.04786 (16)	0.61242 (13)	0.2055 (2)	0.0131 (3)
H6A	−0.0125	0.5431	0.2091	0.016*
H6B	0.0370	0.6713	0.2990	0.016*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.00708 (13)	0.00885 (13)	0.01018 (13)	−0.00067 (8)	0.00204 (9)	0.00051 (8)
O1	0.0092 (5)	0.0119 (5)	0.0173 (5)	−0.0003 (4)	0.0026 (4)	0.0023 (4)
O2	0.0106 (5)	0.0123 (5)	0.0236 (6)	−0.0021 (4)	0.0008 (4)	0.0057 (4)
O3	0.0102 (5)	0.0136 (5)	0.0133 (5)	−0.0013 (4)	0.0019 (4)	−0.0020 (4)
O4	0.0111 (5)	0.0223 (6)	0.0127 (5)	0.0045 (4)	0.0014 (4)	0.0056 (4)
N1	0.0094 (6)	0.0089 (5)	0.0098 (6)	−0.0002 (4)	0.0026 (5)	0.0004 (4)
C1	0.0120 (7)	0.0118 (6)	0.0100 (6)	0.0003 (5)	0.0021 (5)	0.0005 (5)
C2	0.0091 (7)	0.0114 (6)	0.0131 (7)	−0.0011 (5)	0.0029 (5)	0.0013 (5)
C3	0.0125 (7)	0.0127 (6)	0.0129 (7)	0.0015 (5)	0.0037 (6)	−0.0013 (5)
C4	0.0124 (7)	0.0184 (7)	0.0117 (7)	0.0001 (5)	0.0042 (6)	−0.0013 (6)
C5	0.0092 (7)	0.0133 (7)	0.0109 (7)	0.0007 (5)	0.0021 (5)	0.0016 (5)
C6	0.0106 (7)	0.0151 (7)	0.0118 (7)	0.0022 (5)	0.0012 (5)	0.0016 (5)

Geometric parameters (Å, º)

Zn1—O1	2.0488 (10)	N1—C3	1.4882 (18)
Zn1—O1^i	2.0488 (10)	C1—C2	1.533 (2)
Zn1—O3^i	2.1292 (11)	C2—H2A	0.9900
Zn1—O3	2.1292 (11)	C2—H2B	0.9900
Zn1—N1^i	2.1484 (13)	C3—C4	1.516 (2)
Zn1—N1	2.1484 (13)	C3—H3A	0.9900
O1—C1	1.2542 (18)	C3—H3B	0.9900
O2—C1	1.2537 (18)	C4—H4A	0.9900
O3—C4	1.4308 (18)	C4—H4B	0.9900
O3—H3	0.84 (1)	C5—C6	1.519 (2)
O4—C6	1.4212 (17)	C5—H5A	0.9900
O4—H4	0.83 (1)	C5—H5B	0.9900
N1—C2	1.4836 (18)	C6—H6A	0.9900
N1—C5	1.4839 (18)	C6—H6B	0.9900
O1—Zn1—O1^i	180.0	N1—C2—H2A	108.7
O1—Zn1—O3^i	91.59 (4)	C1—C2—H2A	108.7
O1^i—Zn1—O3^i	88.41 (4)	N1—C2—H2B	108.7
O1—Zn1—O3	88.41 (4)	C1—C2—H2B	108.7
O1^i—Zn1—O3	91.59 (4)	H2A—C2—H2B	107.6
O3^i—Zn1—O3	180.0	N1—C3—C4	110.98 (12)
O1—Zn1—N1^i	97.12 (4)	N1—C3—H3A	109.4
O1^i—Zn1—N1^i	82.88 (4)	C4—C3—H3A	109.4
O3^i—Zn1—N1^i	82.74 (4)	N1—C3—H3B	109.4
O3—Zn1—N1^i	97.26 (4)	C4—C3—H3B	109.4
O1—Zn1—N1	82.88 (4)	H3A—C3—H3B	108.0
O1^i—Zn1—N1	97.12 (4)	O3—C4—C3	110.24 (12)
O3^i—Zn1—N1	97.26 (4)	O3—C4—H4A	109.6
O3—Zn1—N1	82.74 (4)	C3—C4—H4A	109.6
N1^i—Zn1—N1	180.0	O3—C4—H4B	109.6
C1—O1—Zn1	115.48 (9)	C3—C4—H4B	109.6
C4—O3—Zn1	109.91 (8)	H4A—C4—H4B	108.1
C4—O3—H3	108.3 (16)	N1—C5—C6	115.44 (12)
Zn1—O3—H3	118.6 (16)	N1—C5—H5A	108.4
C6—O4—H4	105.4 (17)	C6—C5—H5A	108.4
C2—N1—C5	112.49 (11)	N1—C5—H5B	108.4
C2—N1—C3	112.67 (11)	C6—C5—H5B	108.4
C5—N1—C3	111.57 (11)	H5A—C5—H5B	107.5
C2—N1—Zn1	106.95 (8)	O4—C6—C5	106.39 (12)
C5—N1—Zn1	109.26 (9)	O4—C6—H6A	110.5
C3—N1—Zn1	103.34 (9)	C5—C6—H6A	110.5
O2—C1—O1	124.08 (13)	O4—C6—H6B	110.5
O2—C1—C2	116.06 (13)	C5—C6—H6B	110.5
O1—C1—C2	119.86 (13)	H6A—C6—H6B	108.6
N1—C2—C1	114.08 (12)
O3^i—Zn1—O1—C1	−92.62 (10)	O3^i—Zn1—N1—C3	−157.45 (8)
O3—Zn1—O1—C1	87.38 (10)	O3—Zn1—N1—C3	22.55 (8)
N1^i—Zn1—O1—C1	−175.50 (10)	Zn1—O1—C1—O2	178.78 (12)
N1—Zn1—O1—C1	4.50 (10)	Zn1—O1—C1—C2	−0.37 (17)
O1—Zn1—O3—C4	−78.86 (9)	C5—N1—C2—C1	128.95 (13)
O1^i—Zn1—O3—C4	101.14 (9)	C3—N1—C2—C1	−103.88 (14)
N1^i—Zn1—O3—C4	−175.83 (9)	Zn1—N1—C2—C1	8.99 (14)
N1—Zn1—O3—C4	4.17 (9)	O2—C1—C2—N1	174.38 (12)
O1—Zn1—N1—C2	−7.26 (9)	O1—C1—C2—N1	−6.4 (2)
O1^i—Zn1—N1—C2	172.74 (9)	C2—N1—C3—C4	68.96 (15)
O3^i—Zn1—N1—C2	83.44 (9)	C5—N1—C3—C4	−163.38 (12)
O3—Zn1—N1—C2	−96.56 (9)	Zn1—N1—C3—C4	−46.10 (13)
O1—Zn1—N1—C5	−129.27 (9)	Zn1—O3—C4—C3	−30.45 (14)
O1^i—Zn1—N1—C5	50.73 (9)	N1—C3—C4—O3	53.60 (16)
O3^i—Zn1—N1—C5	−38.57 (9)	C2—N1—C5—C6	68.31 (16)
O3—Zn1—N1—C5	141.43 (9)	C3—N1—C5—C6	−59.44 (16)
O1—Zn1—N1—C3	111.84 (9)	Zn1—N1—C5—C6	−173.08 (10)
O1^i—Zn1—N1—C3	−68.16 (9)	N1—C5—C6—O4	179.67 (11)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O2^ii	0.84 (1)	1.85 (1)	2.651 (2)	161 (2)
O4—H4···O2^iii	0.83 (1)	1.89 (1)	2.715 (2)	178 (3)

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