Hexaaqua­zinc(II) bis­(6-hydroxy­pyridine-3-carboxyl­ate)

The Zn atom in the title compound, [Zn(H₂O)₆](C₆H₄NO₃)₂, lies on a special position of 2/m site symmetry in an octa­hedron made up of water mol­ecules. The anion is disordered across a mirror plane. The cation inter­acts with the anion indirectly through hydrogen bonds to form a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](n-O) = 0.003 Å
• Disorder in main residue
• R factor = 0.038
• wR factor = 0.107
• Data-to-parameter ratio = 8.8

checkCIF/PLATON results

No syntax errors found



Alert level A
ABSTM02_ALERT_3_A  The ratio of expected to reported Tmax/Tmin(RR') is < 0.50
            Tmin and Tmax reported:      0.211     0.716
            Tmin' and Tmax expected:      0.593     0.699
            RR' =      0.347
            Please check that your absorption correction is appropriate.

Author Response: The ratio is given by SADABS; SADABS does more than correcting for absorption. This ratio is used rather than the ratio given by SHELXL,

 which calculates it on the basis of \m and the crystal size only.

PLAT061_ALERT_3_A Tmax/Tmin Range Test RR' too Large .............       0.34

Author Response: Same as the above.

Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low .......       0.95
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        Zn1
PLAT301_ALERT_3_B Main Residue  Disorder .........................      29.00 Perc.

Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.98
PLAT088_ALERT_3_C Poor Data / Parameter Ratio ....................       8.78
PLAT152_ALERT_1_C Supplied and Calc Volume s.u. Inconsistent .....          ?
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.24
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........          4
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Rat
              O1W  -H1W1    1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.85(4), Rep   0.850(10) ......       4.00 su-Rat
              O2W  -H2W1    1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.85(4), Rep   0.850(10) ......       4.00 su-Rat
              O2W  -H2W2    1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.840(10) ......       3.00 su-Rat
              O1W  -H1#     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(4), Rep   0.850(10) ......       4.00 su-Rat
              O2W  -H3#     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(4), Rep   0.850(10) ......       4.00 su-Rat
              O2W  -H3#     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(4), Rep   0.850(10) ......       4.00 su-Rat
              O2W  -H4#     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.85(4), Rep   0.850(10) ......       4.00 su-Rat
              O2W  -H4#     1.555   1.555
PLAT736_ALERT_1_C H...A   Calc     1.82(3), Rep   1.820(10) ......       3.00 su-Rat
              H1#  -O1      1.555   1.555
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.13 Ratio

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

  11 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
   5 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion

---

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997; program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXL97.

Hexaaquazinc(II) bis(6-hydroxypyridine-3-carboxylate)

Crystal data

[Zn(H2O)6](C6H4NO3)2	F(000) = 464
Mr = 449.67	Dx = 1.732 Mg m^−3
Monoclinic, C2/m	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2y	Cell parameters from 1640 reflections
a = 11.568 (1) Å	θ = 2.7–27.5°
b = 9.780 (1) Å	µ = 1.49 mm^−1
c = 7.6255 (7) Å	T = 295 K
β = 91.286 (3)°	Block, colorless
V = 862.5 (1) Å^3	0.34 × 0.31 × 0.24 mm
Z = 2

Data collection

Bruker APEX area-detector diffractometer	992 independent reflections
Radiation source: fine-focus sealed tube	979 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
φ and ω scans	θmax = 27.5°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 2002)	h = −14→14
Tmin = 0.211, Tmax = 0.716	k = −12→12
2428 measured reflections	l = −7→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)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0522P)^2 + 1.9207P] where P = (Fo^2 + 2Fc^2)/3
992 reflections	(Δ/σ)max = 0.001
113 parameters	Δρmax = 0.40 e Å^−3
14 restraints	Δρmin = −0.35 e Å^−3

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Zn1	0.5000	0.5000	0.5000	0.0281 (2)
O1	0.8316 (2)	0.6129 (2)	0.6581 (4)	0.049 (1)
O2	1.3227 (3)	0.5770 (5)	0.9709 (6)	0.040 (1)	0.50
O1w	0.6268 (2)	0.6445 (3)	0.4993 (4)	0.062 (1)
O2w	0.4892 (3)	0.5000	0.2219 (5)	0.071 (1)
N1	1.1457 (4)	0.6547 (5)	0.8857 (6)	0.037 (1)	0.50
C1	1.0372 (5)	0.6393 (7)	0.8162 (6)	0.036 (2)	0.50
C2	1.0003 (4)	0.512 (1)	0.7603 (6)	0.034 (1)	0.50
C3	1.0758 (5)	0.4031 (7)	0.7774 (8)	0.036 (1)	0.50
C4	1.1856 (5)	0.4191 (7)	0.8486 (9)	0.036 (1)	0.50
C5	1.2229 (5)	0.5494 (6)	0.9041 (8)	0.032 (1)	0.50
C6	0.8783 (3)	0.5000	0.6860 (5)	0.031 (1)
H2o	1.3265	0.6617	0.9951	0.048*	0.50
H1w1	0.690 (2)	0.628 (3)	0.552 (5)	0.06 (1)*
H1w2	0.627 (3)	0.720 (2)	0.447 (4)	0.04 (1)*
H2w1	0.428 (3)	0.5000	0.159 (6)	0.07 (2)*
H2w2	0.548 (3)	0.5000	0.158 (6)	0.09 (2)*
H1	0.9880	0.7143	0.8062	0.043*	0.50
H3	1.0520	0.3168	0.7399	0.043*	0.50
H4	1.2348	0.3442	0.8598	0.043*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0195 (3)	0.0290 (3)	0.0355 (4)	0.000	−0.0043 (2)	0.000
O1	0.043 (1)	0.032 (1)	0.071 (2)	0.001 (1)	−0.023 (1)	0.010 (1)
O2	0.025 (2)	0.047 (2)	0.048 (2)	−0.001 (2)	−0.010 (2)	−0.004 (2)
O1w	0.031 (1)	0.043 (1)	0.109 (2)	−0.013 (1)	−0.029 (1)	0.034 (1)
O2w	0.034 (2)	0.145 (4)	0.033 (2)	0.000	−0.007 (1)	0.000
N1	0.028 (2)	0.033 (3)	0.049 (3)	0.000 (2)	−0.016 (2)	0.000 (2)
C1	0.027 (3)	0.032 (3)	0.048 (4)	0.001 (2)	−0.012 (3)	0.002 (3)
C2	0.026 (2)	0.043 (4)	0.032 (2)	0.007 (5)	−0.006 (2)	0.006 (4)
C3	0.031 (4)	0.031 (3)	0.045 (4)	0.003 (3)	−0.006 (3)	−0.007 (3)
C4	0.027 (3)	0.029 (3)	0.052 (4)	0.002 (3)	−0.005 (3)	−0.006 (3)
C5	0.023 (3)	0.033 (3)	0.040 (4)	0.006 (2)	−0.005 (2)	0.001 (2)
C6	0.027 (2)	0.032 (2)	0.034 (2)	0.000	−0.0083 (15)	0.000

Geometric parameters (Å, º)

Zn1—O1w	2.037 (2)	C3—C4	1.379 (7)
Zn1—O1w^i	2.037 (2)	C4—C5	1.408 (7)
Zn1—O1w^ii	2.037 (2)	C6—O1^iii	1.246 (3)
Zn1—O1w^iii	2.037 (2)	C6—C2^iii	1.513 (6)
Zn1—O2w	2.121 (4)	O2—H2o	0.85
Zn1—O2w^ii	2.121 (4)	O1w—H1w1	0.84 (1)
O1—C6	1.246 (3)	O1w—H1w2	0.84 (1)
O2—C5	1.280 (7)	O2w—H2w1	0.85 (1)
N1—C1	1.360 (6)	O2w—H2w2	0.85 (1)
N1—C5	1.368 (6)	C1—H1	0.93
C1—C2	1.383 (9)	C3—H3	0.93
C2—C3	1.380 (8)	C4—H4	0.93
C2—C6	1.513 (6)
O1w—Zn1—O1w^i	92.1 (2)	O1^iii—C6—C2^iii	113.2 (4)
O1w—Zn1—O1w^ii	180	O1—C6—C2^iii	121.9 (4)
O1w—Zn1—O1w^iii	87.9 (2)	O1^iii—C6—C2	121.9 (4)
O1w—Zn1—O2w	91.4 (1)	O1—C6—C2	113.2 (4)
O1w—Zn1—O2w^ii	88.7 (1)	Zn1—O1w—H1w1	119 (2)
O2w—Zn1—O2w^ii	180	Zn1—O1w—H1w2	129 (2)
C1—N1—C5	123.5 (6)	H1w1—O1w—H1w2	112 (2)
N1—C1—C2	119.7 (6)	Zn1—O2w—H2w1	126 (4)
C3—C2—C1	118.4 (5)	Zn1—O2w—H2w2	123 (4)
C3—C2—C6	124.1 (7)	H2w1—O2w—H2w2	110 (2)
C1—C2—C6	117.5 (7)	N1—C1—H1	120.2
C4—C3—C2	121.7 (6)	C2—C1—H1	120.2
C3—C4—C5	119.6 (6)	C4—C3—H3	119.2
O2—C5—N1	117.6 (5)	C2—C3—H3	119.2
O2—C5—C4	125.3 (5)	C3—C4—H4	120.2
N1—C5—C4	117.1 (5)	C5—C4—H4	120.2
O1^iii—C6—O1	124.9 (3)
C5—N1—C1—C2	0.2 (3)	C3—C4—C5—O2	−179.5 (5)
N1—C1—C2—C3	0.0 (3)	C3—C4—C5—N1	0.8 (7)
N1—C1—C2—C6	179.3 (4)	C3—C2—C6—O1^iii	10.6 (6)
C1—C2—C3—C4	0.2 (6)	C1—C2—C6—O1^iii	−168.6 (4)
C6—C2—C3—C4	−179.0 (5)	C3—C2—C6—O1	−169.8 (4)
C2—C3—C4—C5	−0.6 (7)	C1—C2—C6—O1	11.0 (5)
C1—N1—C5—O2	179.7 (4)	C3—C2—C6—C2^iii	10.4 (4)
C1—N1—C5—C4	−0.6 (5)	C1—C2—C6—C2^iii	−168.8 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1w—H1w1···O1	0.84 (1)	1.82 (1)	2.655 (3)	174 (3)
O1w—H1w2···O1^iv	0.84 (1)	1.89 (1)	2.706 (3)	166 (3)
O2w—H2w1···O2^v	0.85 (1)	2.01 (2)	2.788 (5)	153 (3)
O2w—H2w1···O2^v	0.85 (1)	2.01 (2)	2.788 (5)	153 (3)
O2w—H2w2···O2^vi	0.85 (1)	1.96 (1)	2.758 (6)	157 (1)
O2w—H2w2···O2^vii	0.85 (1)	1.96 (1)	2.758 (6)	157 (1)
O2—H2o···N1^viii	0.85	2.03	2.86 (1)	165

Symmetry codes: (iv) −x+3/2, −y+3/2, −z+1; (v) x−1, y, z−1; (vi) −x+2, −y+1, −z+1; (vii) −x+2, y, −z+1; (viii) −x+5/2, −y+3/2, −z+2.