Diaqua­malonato(1,10-phenanthro­line)­zinc(II)

In the crystal structure of the title complex, [Zn(C₃H₂O₄)(C₁₂H₈N₂)(H₂O)₂], the Zn^II atom displays a distorted octa­hedral geometry, being coordinated by two N atoms from the 1,10-phenanthroline ligand, two O atoms from different carboxyl­ate groups of the chelating malonate dianion and two O atoms of cis water mol­ecules. The complex mol­ecules are linked to form a three-dimensional supramolecular array by both hydrogen-bonding inter­actions between coordinated water molecules and the uncoordinated carboxyl­ate O atoms of neighboring mol­ecules, and aromatic [pi]-[pi] stacking inter­actions between neighboring phenanthroline rings.

S1. Comment

There has been considerable interest in the design and synthesis of transition metal complexes with carboxylate ligands in coordination chemistry, as a result of the fact that this type of complex has potential application in molecular-based magnets, catalysis, supramolecular chemistry and biological systems (Li et al., 2002; Shi et al., 2000; Devereux et al., 2000). As an important dicarboxylate ligand, the malonate dianion may acts in a chelating bidentate manner and adopt different carboxylate bridging coordination modes, such as syn/syn, syn/anti and anti/anti (Li et al., 1997; Lightfoot et al.,1999; Lis et al., 1979; Muro et al., 1998). Zn^II complexes with the malonate ligand have potential applications in modified metalloenzymes and in precursor systems for Zn-containing ceramic materials. Serval structures of Zn^II complexes with malonate (mal) have been reported, viz. {Na₂[Zn(mal)₂·2H₂O}_n (Lin et al., 2003), Zn₂(mal)₂(pym)(H₂O)]_n.nH₂O (pym is pyrimidine; Delgado et al., 2003) and [Zn₂(H₂O)₂(mal)₂(C₄H₄N₂)] (Zhang et al., 2003). These structures were all found to be polymeric, with the malonate ligands serving as bridges. To the best of our knowledge, no mononuclear Zn^II complexes with the malonate ligand in which malonate acts as a dicarboxylate chelating ligand have been reported. We report here the crystal structure of one such complex, diaquamalonato(1,10-phenanthroline)zinc(II), (I), with a dicaboxylate chelating malonate ligand.

The molecular structure of (I), shown in Fig. 1, consists of discrete monomers. A malonate dianion chelates the Zn^II atom through two O atoms from different carboxylate groups. The Zn^II atom is also coordinated by the two 1,10-phenanthroline N atoms and two O atoms of two cis water molecules. Each malonate ligand forms a six-membered chelate ring with one Zn^II ion in a boat-type configuration; the malonate ligand acts only as a chelating ligand and does not act as a bridge between metal atoms. The carboxylate chelating coordination mode is similar to those of [Mn(mal)(bipy)(H₂O)₂] (bipy is 2,2'-bipyridine; Sain et al., 2003) and [Mn(mal)(phen)(H₂O)₂] (phen is 1,10-phenanthroline; Zhang et al.,2004). The Zn^II atom exhibits a distorted octahedral coordination sphere with the bond angles ranging from 166.21 (6) to 172.07 (6)° for trans angles and from 77.05 (6) to 99.19 (6)° for the other bond angles (Table 1). The Zn—O(carboxylate) bond distances are 2.0618 (13) and 2.0646 (15) Å. In [Zn₂(H₂O)₂(mal)₂(C₄H₄N₂)] (Zhang et al., 2003), the corresponding Zn—O(carboxylate) bond distances are 2.085 (2) and 2.082 (3) Å; the difference is probably due to the effect of the chelating coordination in (I). The Zn—O(water) distances of 2.1152 (17) and 2.1364 (16) Å are comparable to those found in [Zn₂(mal)₂(pym)(H₂O)]_n.nH₂O [2.175 (4) Å; Delgado et al., 2003]. The Zn—N bond lengths are 2.1601 (17) and 2.1745 (17) Å, somewhat longer than in [Zn(male)(H₂O)(phen)]_n [2.1295 (17) and 2.1741 (19) Å; male is maleate; Li et al., 2005].

As shown in Fig. 2, the molecular packing of (I) exhibits a three-dimensional supramolecular structure in which both hydrogen-bonding and π–π stacking interactions play an important role. The complex molecules are linked to one another through hydrogen bonds between coordinated water molecules and the uncoordinated carboxylate O atoms of neighboring molecules to form layers in the crystal structure (Table 2). Neighboring layers are linked to each other through π–π stacking interactions between the phen rings of adjacent molecules, characterized by interplanar distances in the range 3.446 (14) to 3.542 (14) Å.

S2. Experimental

ZnO (0.162 g, 2 mmol) was added slowly to an aqueous solution (15 ml) of malonic acid (0.104 g, 1 mmol). The reaction mixture was stirred for one hour at 353 K, and then an ethanol solution (5 ml) of 1,10-phenanthroline (0.198 g, 1 mmol) was added with continuous stirring. After half an hour, the reaction mixture was cooled to room temperature and filtered. Colorless single crystals were obtained from the filtrate after two weeks.

S3. Refinement

The water H atoms were located in a difference Fourier map and their positional parameters were refined freely [or with O—H distances restrained to 0.XX (s.u.) Å?]; their U_iso(H) values were fixed at 0.063 Ų. The remaining H atoms were positioned geometrically and allowed to ride on their parent atoms with C—H bond lengths of 0.93 or 0.97 Å [U_iso(H) = 1.2U_eq(C)].

Computing details

Data collection: SMART (Bruker, 2000); cell refinement: SMART; data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of (I), showing displacement ellipsoids at the 35% probability level.
	Fig. 2. A view of part of the infinite two-dimensional supramolecular structure of complex (I), showing hydrogen-bonding interactions (dashed lines) in the ab plane (phen moieties are not shown for clarity).
	Fig. 3. The molecular packing of (I), with hydrogen bonds shown as dashed lines (H atoms without H-bonding interacting are not shown).

Diaquamalonato(1,10-phenanthroline)zinc(II)

Crystal data

[Zn(C3H2O4)(C12H8N2)(H2O)2]	F(000) = 784
Mr = 383.65	Dx = 1.712 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P2ybc	Cell parameters from 3676 reflections
a = 10.3369 (11) Å	θ = 0.0–0.0°
b = 9.6662 (10) Å	µ = 1.69 mm^−1
c = 15.4737 (16) Å	T = 292 K
β = 105.720 (2)°	Prism, colorless
V = 1488.3 (3) Å^3	0.27 × 0.20 × 0.18 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	3237 independent reflections
Radiation source: fine-focus sealed tube	2572 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.063
φ and ω scans	θmax = 27.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2000)	h = −13→11
Tmin = 0.659, Tmax = 0.751	k = −12→12
10345 measured reflections	l = −16→19

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)] = 0.033	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.071	H atoms treated by a mixture of independent and constrained refinement
S = 0.95	w = 1/[σ^2(Fo^2) + (0.0343P)^2] where P = (Fo^2 + 2Fc^2)/3
3237 reflections	(Δ/σ)max = 0.001
229 parameters	Δρmax = 0.34 e Å^−3
4 restraints	Δρmin = −0.35 e Å^−3

Special details

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.

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

	x	y	z	Uiso*/Ueq
Zn1	0.65669 (2)	0.39602 (2)	0.231105 (16)	0.02812 (9)
N1	0.85172 (17)	0.30751 (18)	0.29292 (12)	0.0325 (4)
N2	0.77262 (18)	0.57322 (17)	0.29610 (12)	0.0318 (4)
O1	0.58103 (15)	0.20512 (13)	0.18325 (9)	0.0325 (3)
O2	0.45738 (19)	0.07241 (16)	0.07647 (11)	0.0542 (5)
O3	0.69264 (15)	0.43374 (14)	0.10833 (10)	0.0354 (4)
O4	0.67092 (16)	0.38067 (14)	−0.03373 (10)	0.0364 (4)
O5	0.47378 (17)	0.51175 (16)	0.19912 (11)	0.0369 (4)
O6	0.59419 (18)	0.34566 (16)	0.34661 (11)	0.0412 (4)
C1	0.8894 (2)	0.1768 (2)	0.29118 (16)	0.0407 (6)
H1	0.8277	0.1135	0.2582	0.049*
C2	1.0172 (3)	0.1296 (2)	0.33640 (18)	0.0475 (6)
H2	1.0393	0.0367	0.3342	0.057*
C3	1.1088 (3)	0.2207 (3)	0.38359 (17)	0.0516 (7)
H3	1.1948	0.1908	0.4134	0.062*
C4	1.0738 (2)	0.3609 (3)	0.38763 (16)	0.0435 (6)
C5	1.1630 (3)	0.4627 (3)	0.43670 (18)	0.0579 (8)
H5A	1.2509	0.4382	0.4662	0.069*
C6	1.1225 (3)	0.5936 (3)	0.44109 (18)	0.0565 (8)
H6A	1.1822	0.6576	0.4752	0.068*
C7	0.9892 (3)	0.6375 (2)	0.39439 (16)	0.0429 (6)
C8	0.9427 (3)	0.7729 (3)	0.39614 (18)	0.0544 (7)
H8	0.9983	0.8402	0.4301	0.065*
C9	0.8159 (3)	0.8056 (2)	0.34798 (19)	0.0537 (7)
H9	0.7843	0.8956	0.3484	0.064*
C11	0.8991 (2)	0.5405 (2)	0.34368 (14)	0.0315 (5)
C12	0.9429 (2)	0.3990 (2)	0.34160 (14)	0.0322 (5)
C15	0.5161 (2)	0.1810 (2)	0.10202 (14)	0.0302 (5)
C14	0.5049 (2)	0.2940 (2)	0.03250 (14)	0.0320 (5)
H14A	0.4365	0.3590	0.0389	0.038*
H14B	0.4735	0.2524	−0.0265	0.038*
C13	0.6321 (2)	0.37496 (18)	0.03583 (14)	0.0283 (5)
C10	0.7332 (2)	0.7033 (2)	0.29772 (17)	0.0419 (6)
H10	0.6472	0.7275	0.2641	0.050*
H5B	0.455 (3)	0.561 (3)	0.2392 (18)	0.063*
H5C	0.443 (3)	0.545 (3)	0.1521 (17)	0.063*
H6B	0.619 (3)	0.281 (3)	0.3766 (18)	0.063*
H6C	0.579 (3)	0.416 (2)	0.3707 (19)	0.063*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.03131 (16)	0.02779 (13)	0.02259 (15)	−0.00289 (10)	0.00273 (10)	−0.00065 (10)
N1	0.0352 (11)	0.0347 (10)	0.0265 (10)	0.0030 (8)	0.0067 (8)	−0.0020 (8)
N2	0.0328 (11)	0.0322 (9)	0.0310 (11)	−0.0033 (7)	0.0097 (8)	−0.0003 (8)
O1	0.0413 (9)	0.0293 (7)	0.0235 (8)	−0.0075 (6)	0.0031 (7)	−0.0003 (6)
O2	0.0757 (14)	0.0423 (9)	0.0377 (10)	−0.0285 (8)	0.0036 (9)	−0.0031 (7)
O3	0.0437 (10)	0.0373 (8)	0.0245 (8)	−0.0135 (7)	0.0081 (7)	−0.0022 (6)
O4	0.0448 (10)	0.0409 (8)	0.0243 (8)	−0.0040 (7)	0.0105 (7)	0.0015 (6)
O5	0.0421 (10)	0.0398 (9)	0.0247 (9)	0.0103 (7)	0.0018 (8)	−0.0001 (7)
O6	0.0637 (12)	0.0314 (8)	0.0314 (10)	0.0054 (8)	0.0176 (8)	0.0038 (7)
C1	0.0486 (15)	0.0373 (13)	0.0356 (14)	0.0054 (11)	0.0104 (11)	0.0013 (10)
C2	0.0529 (17)	0.0465 (14)	0.0457 (16)	0.0177 (12)	0.0181 (13)	0.0099 (12)
C3	0.0375 (15)	0.0722 (18)	0.0448 (16)	0.0168 (13)	0.0106 (12)	0.0183 (14)
C4	0.0331 (14)	0.0605 (15)	0.0343 (14)	−0.0005 (11)	0.0049 (11)	0.0063 (11)
C5	0.0339 (15)	0.081 (2)	0.0483 (17)	−0.0087 (14)	−0.0062 (13)	0.0114 (15)
C6	0.0438 (16)	0.0748 (19)	0.0409 (16)	−0.0271 (14)	−0.0054 (12)	0.0019 (14)
C7	0.0449 (15)	0.0490 (14)	0.0321 (14)	−0.0167 (11)	0.0058 (11)	−0.0025 (11)
C8	0.068 (2)	0.0445 (14)	0.0498 (17)	−0.0267 (13)	0.0142 (15)	−0.0112 (12)
C9	0.0669 (19)	0.0307 (12)	0.0674 (19)	−0.0090 (12)	0.0246 (16)	−0.0058 (12)
C11	0.0333 (13)	0.0387 (11)	0.0224 (11)	−0.0078 (10)	0.0072 (10)	−0.0002 (9)
C12	0.0312 (12)	0.0426 (12)	0.0222 (11)	−0.0008 (10)	0.0062 (9)	0.0009 (9)
C15	0.0314 (12)	0.0308 (11)	0.0289 (12)	−0.0026 (9)	0.0088 (9)	−0.0014 (9)
C14	0.0303 (12)	0.0375 (11)	0.0237 (11)	−0.0010 (9)	0.0001 (9)	−0.0009 (9)
C13	0.0330 (12)	0.0241 (10)	0.0258 (12)	0.0039 (8)	0.0048 (9)	0.0049 (8)
C10	0.0422 (14)	0.0360 (12)	0.0502 (16)	−0.0018 (10)	0.0171 (12)	−0.0004 (11)

Geometric parameters (Å, º)

Zn1—O1	2.0618 (13)	C2—H2	0.9300
Zn1—O3	2.0646 (15)	C3—C4	1.408 (3)
Zn1—O6	2.1152 (17)	C3—H3	0.9300
Zn1—O5	2.1364 (16)	C4—C12	1.397 (3)
Zn1—N1	2.1601 (17)	C4—C5	1.420 (4)
Zn1—N2	2.1745 (17)	C5—C6	1.340 (4)
N1—C1	1.325 (3)	C5—H5A	0.9300
N1—C12	1.362 (3)	C6—C7	1.436 (4)
N2—C10	1.324 (3)	C6—H6A	0.9300
N2—C11	1.353 (3)	C7—C8	1.397 (3)
O1—C15	1.276 (2)	C7—C11	1.402 (3)
O2—C15	1.224 (2)	C8—C9	1.358 (4)
O3—C13	1.262 (2)	C8—H8	0.9300
O4—C13	1.248 (3)	C9—C10	1.398 (3)
O5—H5B	0.85 (2)	C9—H9	0.9300
O5—H5C	0.78 (2)	C11—C12	1.443 (3)
O6—H6B	0.78 (2)	C15—C14	1.515 (3)
O6—H6C	0.81 (2)	C14—C13	1.518 (3)
C1—C2	1.393 (3)	C14—H14A	0.9700
C1—H1	0.9300	C14—H14B	0.9700
C2—C3	1.353 (4)	C10—H10	0.9300
O1—Zn1—O3	88.45 (6)	C12—C4—C5	119.2 (2)
O1—Zn1—O6	85.67 (6)	C3—C4—C5	123.6 (2)
O3—Zn1—O6	172.07 (6)	C6—C5—C4	121.0 (2)
O1—Zn1—O5	99.19 (6)	C6—C5—H5A	119.5
O3—Zn1—O5	93.61 (6)	C4—C5—H5A	119.5
O6—Zn1—O5	82.10 (7)	C5—C6—C7	121.6 (2)
O1—Zn1—N1	91.27 (6)	C5—C6—H6A	119.2
O3—Zn1—N1	95.64 (6)	C7—C6—H6A	119.2
O6—Zn1—N1	89.82 (7)	C8—C7—C11	117.2 (2)
O5—Zn1—N1	166.21 (6)	C8—C7—C6	123.7 (2)
O1—Zn1—N2	168.23 (6)	C11—C7—C6	119.0 (2)
O3—Zn1—N2	94.15 (6)	C9—C8—C7	119.6 (2)
O6—Zn1—N2	92.68 (7)	C9—C8—H8	120.2
O5—Zn1—N2	92.11 (6)	C7—C8—H8	120.2
N1—Zn1—N2	77.05 (6)	C8—C9—C10	119.7 (2)
C1—N1—C12	117.87 (19)	C8—C9—H9	120.2
C1—N1—Zn1	127.83 (15)	C10—C9—H9	120.2
C12—N1—Zn1	114.26 (14)	N2—C11—C7	123.0 (2)
C10—N2—C11	117.97 (19)	N2—C11—C12	118.20 (18)
C10—N2—Zn1	128.53 (16)	C7—C11—C12	118.8 (2)
C11—N2—Zn1	113.42 (13)	N1—C12—C4	122.7 (2)
C15—O1—Zn1	124.35 (12)	N1—C12—C11	116.95 (19)
C13—O3—Zn1	124.66 (13)	C4—C12—C11	120.3 (2)
Zn1—O5—H5B	119.5 (19)	O2—C15—O1	123.87 (19)
Zn1—O5—H5C	123 (2)	O2—C15—C14	116.95 (19)
H5B—O5—H5C	110 (3)	O1—C15—C14	119.13 (17)
Zn1—O6—H6B	124 (2)	C15—C14—C13	116.62 (17)
Zn1—O6—H6C	110 (2)	C15—C14—H14A	108.1
H6B—O6—H6C	118 (3)	C13—C14—H14A	108.1
N1—C1—C2	123.1 (2)	C15—C14—H14B	108.1
N1—C1—H1	118.4	C13—C14—H14B	108.1
C2—C1—H1	118.4	H14A—C14—H14B	107.3
C3—C2—C1	119.2 (2)	O4—C13—O3	123.3 (2)
C3—C2—H2	120.4	O4—C13—C14	118.13 (18)
C1—C2—H2	120.4	O3—C13—C14	118.59 (19)
C2—C3—C4	120.0 (2)	N2—C10—C9	122.5 (2)
C2—C3—H3	120.0	N2—C10—H10	118.7
C4—C3—H3	120.0	C9—C10—H10	118.8
C12—C4—C3	117.2 (2)
O1—Zn1—N1—C1	1.33 (19)	C4—C5—C6—C7	−1.9 (5)
O3—Zn1—N1—C1	−87.24 (19)	C5—C6—C7—C8	−179.4 (3)
O6—Zn1—N1—C1	86.99 (19)	C5—C6—C7—C11	0.6 (4)
O5—Zn1—N1—C1	140.9 (3)	C11—C7—C8—C9	−1.6 (4)
N2—Zn1—N1—C1	179.8 (2)	C6—C7—C8—C9	178.3 (3)
O1—Zn1—N1—C12	−176.14 (15)	C7—C8—C9—C10	0.4 (4)
O3—Zn1—N1—C12	95.29 (15)	C10—N2—C11—C7	0.2 (3)
O6—Zn1—N1—C12	−90.48 (16)	Zn1—N2—C11—C7	−176.91 (18)
O5—Zn1—N1—C12	−36.6 (4)	C10—N2—C11—C12	−179.5 (2)
N2—Zn1—N1—C12	2.31 (15)	Zn1—N2—C11—C12	3.4 (2)
O1—Zn1—N2—C10	−172.2 (3)	C8—C7—C11—N2	1.3 (4)
O3—Zn1—N2—C10	85.4 (2)	C6—C7—C11—N2	−178.6 (2)
O6—Zn1—N2—C10	−90.5 (2)	C8—C7—C11—C12	−178.9 (2)
O5—Zn1—N2—C10	−8.4 (2)	C6—C7—C11—C12	1.1 (3)
N1—Zn1—N2—C10	−179.7 (2)	C1—N1—C12—C4	1.3 (3)
O1—Zn1—N2—C11	4.6 (4)	Zn1—N1—C12—C4	179.01 (18)
O3—Zn1—N2—C11	−97.86 (15)	C1—N1—C12—C11	−179.1 (2)
O6—Zn1—N2—C11	86.18 (15)	Zn1—N1—C12—C11	−1.3 (3)
O5—Zn1—N2—C11	168.37 (15)	C3—C4—C12—N1	−1.3 (4)
N1—Zn1—N2—C11	−3.01 (14)	C5—C4—C12—N1	179.8 (2)
O3—Zn1—O1—C15	−34.34 (16)	C3—C4—C12—C11	179.1 (2)
O6—Zn1—O1—C15	140.33 (17)	C5—C4—C12—C11	0.2 (4)
O5—Zn1—O1—C15	59.06 (17)	N2—C11—C12—N1	−1.4 (3)
N1—Zn1—O1—C15	−129.95 (17)	C7—C11—C12—N1	178.9 (2)
N2—Zn1—O1—C15	−137.3 (3)	N2—C11—C12—C4	178.2 (2)
O1—Zn1—O3—C13	23.27 (16)	C7—C11—C12—C4	−1.5 (3)
O6—Zn1—O3—C13	−18.9 (5)	Zn1—O1—C15—O2	−170.56 (18)
O5—Zn1—O3—C13	−75.84 (17)	Zn1—O1—C15—C14	6.8 (3)
N1—Zn1—O3—C13	114.40 (17)	O2—C15—C14—C13	−138.8 (2)
N2—Zn1—O3—C13	−168.22 (16)	O1—C15—C14—C13	43.7 (3)
C12—N1—C1—C2	−0.2 (3)	Zn1—O3—C13—O4	−166.87 (14)
Zn1—N1—C1—C2	−177.55 (18)	Zn1—O3—C13—C14	13.6 (3)
N1—C1—C2—C3	−0.9 (4)	C15—C14—C13—O4	125.0 (2)
C1—C2—C3—C4	0.9 (4)	C15—C14—C13—O3	−55.5 (3)
C2—C3—C4—C12	0.1 (4)	C11—N2—C10—C9	−1.5 (3)
C2—C3—C4—C5	179.0 (3)	Zn1—N2—C10—C9	175.11 (18)
C12—C4—C5—C6	1.5 (4)	C8—C9—C10—N2	1.2 (4)
C3—C4—C5—C6	−177.3 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5B···O1^i	0.85 (2)	1.94 (2)	2.772 (2)	168 (3)
O6—H6B···O4^ii	0.78 (2)	2.06 (2)	2.837 (2)	173 (3)
O5—H5C···O4^iii	0.78 (2)	2.02 (2)	2.792 (2)	169 (3)
O6—H6C···O2^i	0.81 (2)	1.81 (2)	2.617 (2)	179 (3)

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