Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801014775/ci6057sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801014775/ci6057Isup2.hkl |
CCDC reference: 175327
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.004 Å
- R factor = 0.028
- wR factor = 0.075
- Data-to-parameter ratio = 15.9
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Colourless single crystals of (I) were grown as transparent needles from a saturated water–acetone mixture containing sarcosine and zinc chloride in stoichiometric ratio.
The H atoms were placed in calculated positions and were allowed to ride on their respective parent atoms using SHELXL97 (Sheldrick, 1997) defaults.
Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: CAD-4 Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 1999); software used to prepare material for publication: SHELXL97.
[ZnCl2(C6H14N2O4)] | Dx = 1.736 Mg m−3 Dm = 1.74 Mg m−3 Dm measured by floatation in a mixture of carbon tetrachloride and bromoform |
Mr = 314.46 | Cu Kα radiation, λ = 1.54180 Å |
Orthorhombic, Pbca | Cell parameters from 25 reflections |
a = 14.191 (2) Å | θ = 15–27° |
b = 10.655 (1) Å | µ = 6.94 mm−1 |
c = 15.917 (2) Å | T = 293 K |
V = 2406.5 (4) Å3 | Needle, colorless |
Z = 8 | 0.16 × 0.12 × 0.10 mm |
F(000) = 1280 |
Enraf-Nonius CAD-4 diffractometer | 2004 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.000 |
Graphite monochromator | θmax = 67.9°, θmin = 5.6° |
ω–2θ scans | h = 0→16 |
Absorption correction: ψ scan (North et al., 1968) | k = 0→12 |
Tmin = 0.400, Tmax = 0.503 | l = 0→19 |
2182 measured reflections | 2 standard reflections every 200 reflections |
2182 independent reflections | intensity decay: 0.1% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.028 | H-atom parameters constrained |
wR(F2) = 0.075 | w = 1/[σ2(Fo2) + (0.0299P)2 + 2.1069P] where P = (Fo2 + 2Fc2)/3 |
S = 1.18 | (Δ/σ)max = 0.001 |
2182 reflections | Δρmax = 0.28 e Å−3 |
137 parameters | Δρmin = −0.43 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.00071 (4) |
[ZnCl2(C6H14N2O4)] | V = 2406.5 (4) Å3 |
Mr = 314.46 | Z = 8 |
Orthorhombic, Pbca | Cu Kα radiation |
a = 14.191 (2) Å | µ = 6.94 mm−1 |
b = 10.655 (1) Å | T = 293 K |
c = 15.917 (2) Å | 0.16 × 0.12 × 0.10 mm |
Enraf-Nonius CAD-4 diffractometer | 2004 reflections with I > 2σ(I) |
Absorption correction: ψ scan (North et al., 1968) | Rint = 0.000 |
Tmin = 0.400, Tmax = 0.503 | 2 standard reflections every 200 reflections |
2182 measured reflections | intensity decay: 0.1% |
2182 independent reflections |
R[F2 > 2σ(F2)] = 0.028 | 0 restraints |
wR(F2) = 0.075 | H-atom parameters constrained |
S = 1.18 | Δρmax = 0.28 e Å−3 |
2182 reflections | Δρmin = −0.43 e Å−3 |
137 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Zn1 | 0.91616 (2) | 0.26684 (3) | 0.374714 (18) | 0.02767 (13) | |
Cl1 | 0.82235 (4) | 0.23686 (7) | 0.26065 (4) | 0.04149 (18) | |
Cl2 | 0.85109 (5) | 0.21851 (6) | 0.50017 (4) | 0.04106 (18) | |
O1A | 0.96149 (12) | 0.43918 (17) | 0.36814 (12) | 0.0407 (5) | |
O1B | 1.02354 (12) | 0.15641 (18) | 0.34808 (11) | 0.0386 (4) | |
O2A | 0.81985 (13) | 0.51561 (19) | 0.40136 (14) | 0.0474 (5) | |
O2B | 1.10244 (14) | 0.1897 (2) | 0.46595 (12) | 0.0502 (5) | |
N1A | 0.86855 (15) | 0.75410 (19) | 0.36977 (12) | 0.0324 (5) | |
H1A1 | 0.8531 | 0.7594 | 0.4245 | 0.039* | |
H1A2 | 0.8165 | 0.7310 | 0.3414 | 0.039* | |
N1B | 1.24257 (13) | 0.0311 (2) | 0.42703 (13) | 0.0322 (5) | |
H1B1 | 1.2600 | 0.1064 | 0.4473 | 0.039* | |
H1B2 | 1.2212 | −0.0151 | 0.4704 | 0.039* | |
C1A | 0.90174 (17) | 0.5272 (2) | 0.37881 (14) | 0.0303 (5) | |
C1B | 1.09122 (16) | 0.1399 (2) | 0.39819 (14) | 0.0277 (5) | |
C2A | 0.94081 (17) | 0.6563 (2) | 0.35948 (16) | 0.0323 (5) | |
H2A1 | 0.9933 | 0.6737 | 0.3967 | 0.039* | |
H2A2 | 0.9642 | 0.6578 | 0.3022 | 0.039* | |
C2B | 1.16529 (17) | 0.0490 (3) | 0.36588 (15) | 0.0322 (5) | |
H2B1 | 1.1359 | −0.0314 | 0.3543 | 0.039* | |
H2B2 | 1.1911 | 0.0807 | 0.3136 | 0.039* | |
C3A | 0.8985 (2) | 0.8799 (3) | 0.3400 (2) | 0.0554 (8) | |
H3A1 | 0.8482 | 0.9389 | 0.3486 | 0.083* | |
H3A2 | 0.9135 | 0.8758 | 0.2813 | 0.083* | |
H3A3 | 0.9530 | 0.9065 | 0.3709 | 0.083* | |
C3B | 1.32584 (18) | −0.0316 (3) | 0.39022 (18) | 0.0448 (7) | |
H3B1 | 1.3737 | −0.0405 | 0.4324 | 0.067* | |
H3B2 | 1.3498 | 0.0180 | 0.3446 | 0.067* | |
H3B3 | 1.3081 | −0.1130 | 0.3697 | 0.067* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Zn1 | 0.01822 (19) | 0.0360 (2) | 0.0288 (2) | 0.00084 (12) | 0.00124 (11) | −0.00157 (13) |
Cl1 | 0.0290 (3) | 0.0618 (4) | 0.0337 (3) | 0.0001 (3) | −0.0053 (2) | −0.0061 (3) |
Cl2 | 0.0417 (3) | 0.0462 (4) | 0.0353 (3) | −0.0046 (3) | 0.0121 (3) | 0.0024 (3) |
O1A | 0.0235 (9) | 0.0372 (10) | 0.0614 (12) | −0.0007 (8) | 0.0015 (8) | −0.0009 (9) |
O1B | 0.0285 (9) | 0.0559 (11) | 0.0314 (9) | 0.0152 (9) | −0.0047 (7) | −0.0046 (8) |
O2A | 0.0295 (9) | 0.0469 (11) | 0.0658 (13) | −0.0015 (8) | 0.0147 (9) | 0.0044 (10) |
O2B | 0.0392 (10) | 0.0691 (14) | 0.0423 (11) | 0.0155 (10) | −0.0106 (9) | −0.0204 (10) |
N1A | 0.0285 (11) | 0.0370 (11) | 0.0318 (11) | −0.0016 (9) | −0.0017 (8) | −0.0007 (9) |
N1B | 0.0213 (9) | 0.0401 (11) | 0.0352 (11) | 0.0056 (9) | 0.0004 (8) | 0.0007 (9) |
C1A | 0.0257 (12) | 0.0403 (14) | 0.0249 (12) | −0.0039 (10) | −0.0008 (9) | −0.0016 (10) |
C1B | 0.0213 (11) | 0.0359 (12) | 0.0259 (11) | −0.0018 (10) | 0.0014 (9) | 0.0021 (10) |
C2A | 0.0254 (12) | 0.0374 (13) | 0.0340 (12) | −0.0033 (11) | 0.0011 (10) | −0.0012 (11) |
C2B | 0.0242 (12) | 0.0431 (14) | 0.0294 (12) | 0.0057 (11) | −0.0012 (9) | −0.0012 (10) |
C3A | 0.0547 (18) | 0.0411 (16) | 0.070 (2) | −0.0005 (14) | 0.0015 (17) | 0.0141 (15) |
C3B | 0.0243 (13) | 0.0592 (18) | 0.0509 (16) | 0.0142 (12) | 0.0065 (12) | 0.0070 (14) |
Zn1—O1A | 1.9484 (19) | N1B—H1B1 | 0.90 |
Zn1—O1B | 1.9713 (17) | N1B—H1B2 | 0.90 |
Zn1—Cl2 | 2.2595 (7) | C1A—C2A | 1.514 (3) |
Zn1—Cl1 | 2.2739 (7) | C1B—C2B | 1.519 (3) |
O1A—C1A | 1.276 (3) | C2A—H2A1 | 0.97 |
O1B—C1B | 1.261 (3) | C2A—H2A2 | 0.97 |
O2A—C1A | 1.223 (3) | C2B—H2B1 | 0.97 |
O2B—C1B | 1.213 (3) | C2B—H2B2 | 0.97 |
N1A—C2A | 1.471 (3) | C3A—H3A1 | 0.96 |
N1A—C3A | 1.484 (3) | C3A—H3A2 | 0.96 |
N1A—H1A1 | 0.90 | C3A—H3A3 | 0.96 |
N1A—H1A2 | 0.90 | C3B—H3B1 | 0.96 |
N1B—C3B | 1.478 (3) | C3B—H3B2 | 0.96 |
N1B—C2B | 1.479 (3) | C3B—H3B3 | 0.96 |
O1A—Zn1—O1B | 107.20 (8) | O1B—C1B—C2B | 113.7 (2) |
O1A—Zn1—Cl2 | 113.40 (6) | N1A—C2A—C1A | 111.4 (2) |
O1B—Zn1—Cl2 | 111.71 (6) | N1A—C2A—H2A1 | 109.3 |
O1A—Zn1—Cl1 | 106.43 (6) | C1A—C2A—H2A1 | 109.3 |
O1B—Zn1—Cl1 | 101.36 (5) | N1A—C2A—H2A2 | 109.3 |
Cl2—Zn1—Cl1 | 115.74 (3) | C1A—C2A—H2A2 | 109.3 |
C1A—O1A—Zn1 | 117.80 (16) | H2A1—C2A—H2A2 | 108.0 |
C1B—O1B—Zn1 | 122.43 (16) | N1B—C2B—C1B | 111.88 (19) |
C2A—N1A—C3A | 113.9 (2) | N1B—C2B—H2B1 | 109.2 |
C2A—N1A—H1A1 | 108.8 | C1B—C2B—H2B1 | 109.2 |
C3A—N1A—H1A1 | 108.8 | N1B—C2B—H2B2 | 109.2 |
C2A—N1A—H1A2 | 108.8 | C1B—C2B—H2B2 | 109.2 |
C3A—N1A—H1A2 | 108.8 | H2B1—C2B—H2B2 | 107.9 |
H1A1—N1A—H1A2 | 107.7 | N1A—C3A—H3A1 | 109.5 |
C3B—N1B—C2B | 112.97 (19) | N1A—C3A—H3A2 | 109.5 |
C3B—N1B—H1B1 | 109.0 | H3A1—C3A—H3A2 | 109.5 |
C2B—N1B—H1B1 | 109.0 | N1A—C3A—H3A3 | 109.5 |
C3B—N1B—H1B2 | 109.0 | H3A1—C3A—H3A3 | 109.5 |
C2B—N1B—H1B2 | 109.0 | H3A2—C3A—H3A3 | 109.5 |
H1B1—N1B—H1B2 | 107.8 | N1B—C3B—H3B1 | 109.5 |
O2A—C1A—O1A | 126.6 (2) | N1B—C3B—H3B2 | 109.5 |
O2A—C1A—C2A | 120.0 (2) | H3B1—C3B—H3B2 | 109.5 |
O1A—C1A—C2A | 113.4 (2) | N1B—C3B—H3B3 | 109.5 |
O2B—C1B—O1B | 127.0 (2) | H3B1—C3B—H3B3 | 109.5 |
O2B—C1B—C2B | 119.3 (2) | H3B2—C3B—H3B3 | 109.5 |
O1B—Zn1—O1A—C1A | 176.31 (17) | Zn1—O1B—C1B—O2B | −2.6 (4) |
Cl2—Zn1—O1A—C1A | −59.92 (18) | Zn1—O1B—C1B—C2B | 178.76 (16) |
Cl1—Zn1—O1A—C1A | 68.47 (18) | C3A—N1A—C2A—C1A | −171.6 (2) |
O1A—Zn1—O1B—C1B | 72.3 (2) | O2A—C1A—C2A—N1A | −1.3 (3) |
Cl2—Zn1—O1B—C1B | −52.5 (2) | O1A—C1A—C2A—N1A | 178.0 (2) |
Cl1—Zn1—O1B—C1B | −176.30 (18) | C3B—N1B—C2B—C1B | −166.3 (2) |
Zn1—O1A—C1A—O2A | 8.0 (3) | O2B—C1B—C2B—N1B | 2.1 (3) |
Zn1—O1A—C1A—C2A | −171.24 (15) | O1B—C1B—C2B—N1B | −179.2 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1A1···O2Bi | 0.90 | 1.93 | 2.714 (3) | 144 |
N1A—H1A2···Cl1ii | 0.90 | 2.35 | 3.223 (2) | 163 |
N1B—H1B1···Cl2iii | 0.90 | 2.42 | 3.291 (2) | 164 |
N1B—H1B2···Cl2iv | 0.90 | 2.44 | 3.191 (2) | 141 |
N1B—H1B2···O2Aiii | 0.90 | 2.48 | 2.985 (3) | 116 |
C2A—H2A2···O1Bv | 0.97 | 2.40 | 3.342 (3) | 164 |
C2B—H2B2···Cl1vi | 0.97 | 2.76 | 3.610 (3) | 146 |
C3A—H3A1···O2Aii | 0.96 | 2.66 | 3.555 (4) | 156 |
Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) −x+3/2, y+1/2, z; (iii) x+1/2, −y+1/2, −z+1; (iv) −x+2, −y, −z+1; (v) −x+2, y+1/2, −z+1/2; (vi) x+1/2, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [ZnCl2(C6H14N2O4)] |
Mr | 314.46 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 293 |
a, b, c (Å) | 14.191 (2), 10.655 (1), 15.917 (2) |
V (Å3) | 2406.5 (4) |
Z | 8 |
Radiation type | Cu Kα |
µ (mm−1) | 6.94 |
Crystal size (mm) | 0.16 × 0.12 × 0.10 |
Data collection | |
Diffractometer | Enraf-Nonius CAD-4 diffractometer |
Absorption correction | ψ scan (North et al., 1968) |
Tmin, Tmax | 0.400, 0.503 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2182, 2182, 2004 |
Rint | 0.000 |
(sin θ/λ)max (Å−1) | 0.601 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.028, 0.075, 1.18 |
No. of reflections | 2182 |
No. of parameters | 137 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.28, −0.43 |
Computer programs: CAD-4 Software (Enraf-Nonius, 1989), CAD-4 Software, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), PLATON (Spek, 1999), SHELXL97.
Zn1—O1A | 1.9484 (19) | O2B—C1B | 1.213 (3) |
Zn1—O1B | 1.9713 (17) | N1A—C2A | 1.471 (3) |
Zn1—Cl2 | 2.2595 (7) | N1A—C3A | 1.484 (3) |
Zn1—Cl1 | 2.2739 (7) | N1B—C3B | 1.478 (3) |
O1A—C1A | 1.276 (3) | N1B—C2B | 1.479 (3) |
O1B—C1B | 1.261 (3) | C1A—C2A | 1.514 (3) |
O2A—C1A | 1.223 (3) | C1B—C2B | 1.519 (3) |
O1A—Zn1—O1B | 107.20 (8) | O2A—C1A—O1A | 126.6 (2) |
O1A—Zn1—Cl2 | 113.40 (6) | O2A—C1A—C2A | 120.0 (2) |
O1B—Zn1—Cl2 | 111.71 (6) | O1A—C1A—C2A | 113.4 (2) |
O1A—Zn1—Cl1 | 106.43 (6) | O2B—C1B—O1B | 127.0 (2) |
O1B—Zn1—Cl1 | 101.36 (5) | O2B—C1B—C2B | 119.3 (2) |
Cl2—Zn1—Cl1 | 115.74 (3) | O1B—C1B—C2B | 113.7 (2) |
C2A—N1A—C3A | 113.9 (2) | N1A—C2A—C1A | 111.4 (2) |
C3B—N1B—C2B | 112.97 (19) | N1B—C2B—C1B | 111.88 (19) |
C3A—N1A—C2A—C1A | −171.6 (2) | C3B—N1B—C2B—C1B | −166.3 (2) |
O2A—C1A—C2A—N1A | −1.3 (3) | O2B—C1B—C2B—N1B | 2.1 (3) |
O1A—C1A—C2A—N1A | 178.0 (2) | O1B—C1B—C2B—N1B | −179.2 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1A1···O2Bi | 0.90 | 1.93 | 2.714 (3) | 144.3 |
N1A—H1A2···Cl1ii | 0.90 | 2.35 | 3.223 (2) | 162.5 |
N1B—H1B1···Cl2iii | 0.90 | 2.42 | 3.291 (2) | 163.5 |
N1B—H1B2···Cl2iv | 0.90 | 2.44 | 3.191 (2) | 140.7 |
N1B—H1B2···O2Aiii | 0.90 | 2.48 | 2.985 (3) | 116.3 |
C2A—H2A2···O1Bv | 0.97 | 2.40 | 3.342 (3) | 164.1 |
C2B—H2B2···Cl1vi | 0.97 | 2.76 | 3.610 (3) | 146.2 |
C3A—H3A1···O2Aii | 0.96 | 2.66 | 3.555 (4) | 155.9 |
Symmetry codes: (i) −x+2, −y+1, −z+1; (ii) −x+3/2, y+1/2, z; (iii) x+1/2, −y+1/2, −z+1; (iv) −x+2, −y, −z+1; (v) −x+2, y+1/2, −z+1/2; (vi) x+1/2, y, −z+1/2. |
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Sarcosine (N-methylglycine, CH3NH2+CH2COO-), an intermediate in the metabolism of choline, occurs naturally in large amounts in starfish and sea urchins. The crystal structure of sarcosine itself was previously determined in our laboratory (Mostad & Natarajan, 1989). Zinc–amino acid complexes are interesting as zinc is known to compete successfully with cadmium for protein binding sites. Zinc also plays an important biological role in the formation of a structural motif called zinc fingers which are characteristic of certain proteins that bind to DNA. Recently, the crystal structure of a complex of sarcosine with zinc chloride, namely trichloro(sarcosinio)zinc(II) monohydrate (Krishnakumar et al., 2001), in which the amino acid exhibits an unusual cationic form, was reported. The present work reports the crystal structure of a complex, (I), of sarcosine with zinc chloride where the amino acid adopts the usually expected zwitterionic form. The crystal structures of complexes of ZnCl2 with glycine (Hariharan et al., 1989), L-proline (Yukawa et al., 1985) and L-histidine (Foster et al., 1993) have already been reported.
In Fig. 1, the molecular structure and atom-numbering scheme adopted by (I) are shown. Both the sarcosine molecules in the asymmetric unit exist as zwitterions each with a positively charged amino group and a negatively charged carboxylate group. However, the C1—O1 and C1—O2 bond lengths in molecule A [1.276 (3) and 1.223 (3) Å, respectively] and molecule B [1.261 (3) and 1.213 (3) Å, respectively] show significant deviations from those usually exhibited by a zwitterion. The larger value observed in the C1—O1 bond lengths may be due to the fact that both the O1 atoms of molecule A and B participate in the coordination environment around the metal. The angle between the planes formed by the atoms of the two sarcosine molecules coordinating to Zn is 81.5 (1)°.
Zinc is known to have both tetrahedral and octahedral coordination in crystal structures (Cingi et al., 1972). In the present structure, zinc has a distorted tetrahedral environment with two Cl atoms and two carboxyl O atoms, one each from the two crystallographically independent sarcosine molecules in the asymmetric unit. The angles around the Zn atom range from 101.36 (5) to 115.74 (3)°. The coordination environment around Zn in trichloro(sarcosinio)zinc(II) monohydrate, however, is different since it involves three chlorines and one of the carboxyl O atoms.
Head-to-tail hydrogen bonds between the amino acid molecules, in addition to N—H···Cl, C—H···O and C—H···Cl hydrogen bonds, stabilize the three-dimensional network of the molecules. The crystal structure of (I) does not bear any relation either to that of trichloro(sarcosinio)zinc(II) monohydrate or to those of sarcosine cadmium chloride (Krishnakumar et al., 1996) and sarcosine barium chloride tetrahydrate (Krishnakumar & Natarajan, 1995). However, the unit-cell parameters of (I) and those of sarcosine barium chloride tetrahydrate bear an interesting relationship as b and c axes in them are very nearly equal and the cell length a in (I) is twice that of the other.