Di­aqua­bis(N,N-diethyl­nicotin­amide)­bis(2-hydroxy­benzoato)­zinc(II)

The title compound, [Zn(C₇H₅O₃)₂(C₁₀H₁₄N₂O)₂(H₂O)₂], crystallizes as centrosymmetric mononuclear mol­ecules with octahedrally coordinated zinc, all pairs of equivalent ligands being mutually trans. Intramolecular hydrogen bonding links each aqua ligand and the hydroxy group of a 2-hydroxy­benzoate ligand with the uncoordinated carboxyl­ate O atom of the same carboxyl­ate ligand, lengthening this C-O bond so that it has almost the same length as that for the coordinated O atom. Intermolecular hydrogen bonding between aqua ligands and the carbonyl O atoms of N,N-diethyl­nicotin­amide ligands link the mol­ecules together into chains.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.007 Å
• R factor = 0.050
• wR factor = 0.128
• Data-to-parameter ratio = 10.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


 Alert Level B:



THETM_01  Alert B The value of sine(theta_max)/wavelength is less than 0.575
          Calculated sin(theta_max)/wavelength =    0.5556


 0 Alert Level A = Potentially serious problem

 1 Alert Level B = Potential problem

 0 Alert Level C = Please check

---

S1. Comment

The title compound, (I), was prepared as part of a series of studies of the coordination chemistry of the ligand N,N-diethylnicotinamide (DENA). It has a relatively undistorted octahedral coordination geometry for the Zn atom, which lies on an inversion centre, so that all pairs of equivalent ligands lie mutually trans (Fig. 1). A rigorously centrosymmetric structure has been found for all previously reported metal complexes of DENA having a formula [M(OH₂)₂(DENA)₂L₂], where L is any monodentate ligand (Bigoli et al., 1973; Hokelek & Necefoglu, 1997; Hokelek et al., 1997; Melnik et al., 1996; Sergienko et al., 1979, 1980).

The carboxylates act as monodentate ligands, but the near equality of the two C—O bond lengths in each carboxylate group (Table 1) indicate a delocalized bonding arrangement rather than localized single and double bonds. This may be due, in part, to the involvement of the uncoordinated O4 atom as acceptor of two hydrogen bonds. Both of these are intramolecular: one is within the ligand, with the ortho-hydroxy group O5 acting as donor, while the other is between ligands, the donor being an aqua ligand (Table 2). The aqua ligand also acts as donor in an intermolecular hydrogen bond, and pairs of these link molecules together into a chain along the a axis, as shown in Fig. 2.

We have found very similar features, but without the intra-ligand hydrogen bond, in the corresponding complex with 4-nitrobenzoate replacing 2-hydroxybenzoate (Necefoglu et al., 2001).

S2. Experimental

The title compound was prepared by the reaction of 0.01 mol of zinc salicylate and 0.02 mol of diethylnicotinamide in 80 ml water. The mixture was filtered and set aside for crystallization at ambient temperature for several days, giving suitable colourless single crystals.

S3. Refinement

Data were collected at room temperature, because attempts to cool the crystals led to degradation of the crystal quality and the diffraction pattern, possibly as a result of a phase transition. Since this was an early experiment with one of the first commercial CCD diffractometers, operating parameters were not yet optimized; one consequence is the rather low maximum θ, as a result of a crystal-to-detector distance of approximately 6 cm.

H atoms were placed geometrically and refined with a riding model (including free rotation about C—C bonds), and with U_iso constrained to be 1.2 (1.5 for methyl groups) times U_eq of the carrier atom, except for the aqua ligands; for these, the H atoms were refined with the restraint of equal O—H bond lengths and with individual isotropic displacement parameters.

Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and local programs.

Figures

	Fig. 1. The molecular structure of (I) with atom labels and 30% probability ellipsoids for non-H atoms.
	Fig. 2. Two molecules showing intramolecular and intermolecular hydrogen bonds and the unit-cell outline.

Diaquabis(N,N-diethylnicotinamide)bis(2-hydroxybenzoato)zinc(II)

Crystal data

[Zn(C7H5O3)2(C10H14N2O)2(H2O)2]	Z = 1
Mr = 732.09	F(000) = 384
Triclinic, P1	Dx = 1.362 Mg m^−3
a = 7.652 (7) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.903 (6) Å	Cell parameters from 61 reflections
c = 14.664 (16) Å	θ = 1.0–23.5°
α = 97.38 (8)°	µ = 0.75 mm^−1
β = 95.06 (7)°	T = 298 K
γ = 114.22 (6)°	Block, colourless
V = 892.5 (14) Å^3	0.37 × 0.26 × 0.22 mm

Data collection

Bruker SMART 1K CCD diffractometer	2523 independent reflections
Radiation source: sealed tube	2425 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.055
Detector resolution: 8.192 pixels mm^-1	θmax = 23.3°, θmin = 1.4°
ω rotation with narrow frames scans	h = −8→4
Absorption correction: multi-scan (XPREP; Sheldrick, 1997)	k = −9→9
Tmin = 0.75, Tmax = 0.85	l = −15→16
3534 measured reflections

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)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.128	H atoms treated by a mixture of independent and constrained refinement
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0461P)^2 + 1.2437P] where P = (Fo^2 + 2Fc^2)/3
2523 reflections	(Δ/σ)max < 0.001
234 parameters	Δρmax = 0.56 e Å^−3
1 restraint	Δρmin = −0.46 e Å^−3

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

	x	y	z	Uiso*/Ueq
Zn	0.5000	0.5000	0.5000	0.0431 (2)
O1	0.7598 (4)	0.5036 (4)	0.5719 (2)	0.0555 (7)
H1A	0.769 (9)	0.423 (6)	0.587 (4)	0.10 (2)*
H1B	0.767 (9)	0.567 (6)	0.619 (3)	0.10 (2)*
N1	0.6859 (4)	0.7123 (4)	0.4449 (2)	0.0454 (7)
C1	0.6663 (6)	0.8557 (5)	0.4531 (3)	0.0479 (9)
H1	0.5691	0.8641	0.4843	0.057*
C2	0.7837 (6)	0.9916 (5)	0.4174 (3)	0.0539 (10)
H2	0.7661	1.0895	0.4245	0.065*
C3	0.9270 (6)	0.9797 (5)	0.3712 (3)	0.0509 (10)
H3	1.0069	1.0694	0.3459	0.061*
C4	0.9520 (5)	0.8332 (5)	0.3624 (2)	0.0431 (9)
C5	0.8293 (6)	0.7034 (5)	0.4019 (3)	0.0461 (9)
H5	0.8476	0.6060	0.3982	0.055*
C6	1.1174 (6)	0.8132 (5)	0.3234 (3)	0.0476 (9)
O2	1.2340 (4)	0.7879 (4)	0.3756 (2)	0.0630 (8)
N2	1.1388 (5)	0.8276 (5)	0.2346 (2)	0.0580 (9)
C7	1.3127 (8)	0.8214 (6)	0.2019 (4)	0.0772 (15)
H7A	1.4223	0.8808	0.2514	0.093*
H7B	1.3396	0.8800	0.1498	0.093*
C8	1.2965 (11)	0.6483 (8)	0.1722 (5)	0.108 (2)
H8A	1.4202	0.6546	0.1598	0.163*
H8B	1.2022	0.5943	0.1169	0.163*
H8C	1.2568	0.5852	0.2210	0.163*
C9	0.9911 (9)	0.8369 (7)	0.1663 (3)	0.0779 (15)
H9A	1.0563	0.9086	0.1238	0.093*
H9B	0.9190	0.8882	0.1990	0.093*
C10	0.8532 (12)	0.6721 (9)	0.1118 (6)	0.134 (3)
H10A	0.7612	0.6867	0.0691	0.201*
H10B	0.7859	0.6009	0.1532	0.201*
H10C	0.9229	0.6217	0.0776	0.201*
O3	0.5262 (4)	0.3424 (3)	0.38810 (18)	0.0514 (7)
C11	0.4457 (6)	0.3091 (4)	0.3048 (3)	0.0455 (9)
O4	0.2814 (4)	0.3064 (4)	0.2802 (2)	0.0644 (8)
C12	0.5516 (6)	0.2715 (5)	0.2300 (3)	0.0459 (9)
C13	0.4707 (6)	0.2373 (5)	0.1359 (3)	0.0546 (10)
O5	0.3004 (6)	0.2377 (5)	0.1080 (2)	0.0830 (10)
H5A	0.2557	0.2617	0.1536	0.125*
C14	0.5704 (8)	0.2019 (6)	0.0682 (3)	0.0712 (14)
H14	0.5183	0.1805	0.0056	0.085*
C15	0.7453 (9)	0.1982 (7)	0.0927 (4)	0.0820 (15)
H15	0.8100	0.1721	0.0468	0.098*
C16	0.8262 (8)	0.2330 (6)	0.1854 (4)	0.0735 (13)
H16	0.9456	0.2316	0.2020	0.088*
C17	0.7288 (6)	0.2698 (5)	0.2530 (3)	0.0558 (10)
H17	0.7837	0.2938	0.3153	0.067*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.0461 (4)	0.0449 (4)	0.0400 (4)	0.0179 (3)	0.0129 (3)	0.0141 (3)
O1	0.0563 (18)	0.063 (2)	0.0539 (19)	0.0304 (16)	0.0113 (14)	0.0148 (16)
N1	0.0475 (18)	0.0452 (18)	0.0451 (18)	0.0190 (15)	0.0129 (14)	0.0129 (14)
C1	0.052 (2)	0.051 (2)	0.049 (2)	0.0277 (19)	0.0108 (18)	0.0124 (18)
C2	0.067 (3)	0.050 (2)	0.058 (2)	0.035 (2)	0.014 (2)	0.0169 (19)
C3	0.054 (2)	0.050 (2)	0.052 (2)	0.0200 (19)	0.0139 (19)	0.0196 (18)
C4	0.046 (2)	0.044 (2)	0.040 (2)	0.0183 (17)	0.0089 (16)	0.0120 (16)
C5	0.050 (2)	0.043 (2)	0.049 (2)	0.0216 (18)	0.0090 (18)	0.0120 (17)
C6	0.050 (2)	0.043 (2)	0.053 (2)	0.0197 (18)	0.0132 (19)	0.0148 (18)
O2	0.0632 (19)	0.075 (2)	0.0636 (19)	0.0388 (16)	0.0135 (15)	0.0200 (15)
N2	0.068 (2)	0.065 (2)	0.052 (2)	0.0342 (19)	0.0218 (18)	0.0193 (17)
C7	0.093 (4)	0.077 (3)	0.084 (3)	0.046 (3)	0.051 (3)	0.033 (3)
C8	0.143 (6)	0.089 (4)	0.135 (6)	0.072 (4)	0.080 (5)	0.044 (4)
C9	0.107 (4)	0.090 (4)	0.054 (3)	0.054 (3)	0.024 (3)	0.024 (3)
C10	0.131 (7)	0.108 (5)	0.138 (7)	0.036 (5)	−0.027 (5)	0.022 (5)
O3	0.0654 (18)	0.0523 (16)	0.0399 (15)	0.0274 (14)	0.0116 (13)	0.0101 (12)
C11	0.048 (2)	0.0358 (19)	0.050 (2)	0.0137 (17)	0.0138 (18)	0.0106 (16)
O4	0.0568 (19)	0.077 (2)	0.0593 (18)	0.0320 (16)	0.0071 (14)	0.0028 (15)
C12	0.054 (2)	0.040 (2)	0.042 (2)	0.0174 (18)	0.0147 (17)	0.0093 (16)
C13	0.061 (3)	0.054 (2)	0.049 (2)	0.024 (2)	0.008 (2)	0.0092 (19)
O5	0.085 (3)	0.108 (3)	0.060 (2)	0.050 (2)	0.0021 (18)	0.005 (2)
C14	0.097 (4)	0.072 (3)	0.043 (2)	0.034 (3)	0.018 (2)	0.005 (2)
C15	0.097 (4)	0.092 (4)	0.066 (3)	0.047 (3)	0.037 (3)	0.010 (3)
C16	0.071 (3)	0.084 (3)	0.076 (3)	0.042 (3)	0.023 (3)	0.012 (3)
C17	0.060 (3)	0.059 (2)	0.052 (2)	0.028 (2)	0.013 (2)	0.0089 (19)

Geometric parameters (Å, º)

Zn—O1^i	2.153 (4)	C7—H7B	0.970
Zn—O1	2.153 (4)	C8—H8A	0.960
Zn—O3^i	2.098 (3)	C8—H8B	0.960
Zn—O3	2.098 (3)	C8—H8C	0.960
Zn—N1^i	2.153 (4)	C9—C10	1.478 (9)
Zn—N1	2.154 (4)	C9—H9A	0.970
O1—H1A	0.81 (4)	C9—H9B	0.970
O1—H1B	0.81 (4)	C10—H10A	0.960
N1—C1	1.337 (5)	C10—H10B	0.960
N1—C5	1.338 (5)	C10—H10C	0.960
C1—C2	1.378 (6)	C11—O3	1.259 (5)
C1—H1	0.930	C11—O4	1.266 (5)
C2—C3	1.372 (6)	C11—C12	1.502 (6)
C2—H2	0.930	C12—C17	1.375 (6)
C3—C4	1.386 (6)	C12—C13	1.403 (6)
C3—H3	0.930	C13—O5	1.332 (6)
C4—C5	1.389 (5)	C13—C14	1.385 (6)
C4—C6	1.499 (6)	O5—H5A	0.820
C5—H5	0.930	C14—C15	1.369 (8)
C6—O2	1.234 (5)	C14—H14	0.930
C6—N2	1.342 (5)	C15—C16	1.383 (8)
N2—C7	1.473 (6)	C15—H15	0.930
N2—C9	1.478 (6)	C16—C17	1.376 (6)
C7—C8	1.497 (7)	C16—H16	0.930
C7—H7A	0.970	C17—H17	0.930
O3^i—Zn—O3	180.0	N2—C7—H7B	108.6
O3^i—Zn—O1^i	87.07 (14)	C8—C7—H7B	108.6
O3—Zn—O1^i	92.93 (14)	H7A—C7—H7B	107.6
O3^i—Zn—O1	92.93 (14)	C7—C8—H8A	109.5
O3—Zn—O1	87.07 (14)	C7—C8—H8B	109.5
O1^i—Zn—O1	180.0	H8A—C8—H8B	109.5
O3^i—Zn—N1^i	88.81 (14)	C7—C8—H8C	109.5
O3—Zn—N1^i	91.19 (14)	H8A—C8—H8C	109.5
O1^i—Zn—N1^i	87.13 (14)	H8B—C8—H8C	109.5
O1—Zn—N1^i	92.87 (14)	N2—C9—C10	113.6 (5)
O3^i—Zn—N1	91.19 (14)	N2—C9—H9A	108.8
O3—Zn—N1	88.81 (14)	C10—C9—H9A	108.8
O1^i—Zn—N1	92.87 (14)	N2—C9—H9B	108.8
O1—Zn—N1	87.13 (14)	C10—C9—H9B	108.8
N1^i—Zn—N1	180.0	H9A—C9—H9B	107.7
Zn—O1—H1A	125 (5)	C9—C10—H10A	109.5
Zn—O1—H1B	96 (4)	C9—C10—H10B	109.5
H1A—O1—H1B	109 (6)	H10A—C10—H10B	109.5
C1—N1—C5	117.9 (3)	C9—C10—H10C	109.5
C1—N1—Zn	122.6 (3)	H10A—C10—H10C	109.5
C5—N1—Zn	119.5 (3)	H10B—C10—H10C	109.5
N1—C1—C2	122.9 (4)	C11—O3—Zn	127.7 (3)
N1—C1—H1	118.5	O3—C11—O4	124.0 (4)
C2—C1—H1	118.5	O3—C11—C12	118.0 (4)
C3—C2—C1	118.8 (4)	O4—C11—C12	118.1 (4)
C3—C2—H2	120.6	C17—C12—C13	119.2 (4)
C1—C2—H2	120.6	C17—C12—C11	120.4 (4)
C2—C3—C4	119.6 (4)	C13—C12—C11	120.4 (4)
C2—C3—H3	120.2	O5—C13—C14	117.9 (4)
C4—C3—H3	120.2	O5—C13—C12	122.7 (4)
C3—C4—C5	117.8 (4)	C14—C13—C12	119.4 (4)
C3—C4—C6	124.1 (3)	C13—O5—H5A	109.5
C5—C4—C6	117.7 (3)	C15—C14—C13	120.4 (5)
N1—C5—C4	123.0 (4)	C15—C14—H14	119.8
N1—C5—H5	118.5	C13—C14—H14	119.8
C4—C5—H5	118.5	C14—C15—C16	120.4 (5)
O2—C6—N2	121.7 (4)	C14—C15—H15	119.8
O2—C6—C4	118.2 (4)	C16—C15—H15	119.8
N2—C6—C4	120.1 (4)	C17—C16—C15	119.5 (5)
C6—N2—C7	118.0 (4)	C17—C16—H16	120.3
C6—N2—C9	123.6 (4)	C15—C16—H16	120.3
C7—N2—C9	118.3 (4)	C12—C17—C16	121.1 (4)
N2—C7—C8	114.5 (5)	C12—C17—H17	119.4
N2—C7—H7A	108.6	C16—C17—H17	119.4
C8—C7—H7A	108.6

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
O1—H1A···O2^ii	0.81 (4)	2.01 (4)	2.817 (5)	175 (6)
O1—H1B···O4^i	0.81 (4)	1.90 (4)	2.698 (5)	166 (6)
O5—H5A···O4	0.82	1.82	2.551 (5)	147

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