μ-2,3,5,6-Tetra-2-pyridylpyrazine-κN,N,N:κN,N,N-bis-[(methanol-κO)(nitrato-κO,O')(nitrato-κO)cadmium(II)].

The title complex, [Cd(2)(NO(3))(4)(C(24)H(16)N(6))(CH(4)O)(2)], displays a centrosymmetric dinuclear structure, in which the 2,3,5,6-tetra-2-pyridinylpyrazine (tppz) ligand links two Cd ions separated by 7.323 (4) Å. Each Cd(II) center is seven-coordinated by three N-atom donors of tppz in one plane, by two O atoms nearly normal to this plane, and by two O atoms 0.393 (3) and 0.488 (3) Å from that plane. The two Cd(II) ions are above and below the plane of the pyrazine ring of the tppz ligand, oriented with respect to the pyridine rings at dihedral angles of 38.01 (3) and 31.90 (3)°. The dihedral angle between the two pyridine rings is 41.11 (3)°. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules.

Related literature

For related literature, see: Bock et al. (1992 ▶); Carranza et al. (2004 ▶); Goodwin & Lyons (1959 ▶); Graf et al. (1993 ▶, 1997 ▶); Greaves & Stoeckli-Evans (1992 ▶); Hadadzadeh et al. (2006 ▶); Laine et al. (1995 ▶); Sakai & Kurashima (2003 ▶); Yamada et al. (2000 ▶); Zhang et al. (2005 ▶).

Experimental

Crystal data

[Cd2(NO3)4(C24H16N6)(CH4O)2]

M = 925.37

Monoclinic,

a = 9.0777 (12) Å

b = 10.8949 (9) Å

c = 16.690 (2) Å

β = 93.847 (10)°

V = 1646.9 (3) Å3

Z = 2

Mo Kα radiation

μ = 1.38 mm−1

T = 298 (2) K

0.50 × 0.40 × 0.25 mm

Data collection

Stoe IPDSII diffractometer

Absorption correction: numerical (X-SHAPE; Stoe & Cie, 2005 ▶) T min = 0.510, T max = 0.710

4664 measured reflections

4642 independent reflections

4223 reflections with I > 2σ(I)

R int = 0.075

Refinement

R[F 2 > 2σ(F 2)] = 0.062

wR(F 2) = 0.171

S = 1.07

4642 reflections

239 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 1.00 e Å−3

Δρmin = −0.95 e Å−3

Data collection: X-AREA (Stoe & Cie, 2005 ▶); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2005 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808022320/hk2497sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808022320/hk2497Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

[Cd2(NO3)4(C24H16N6)(CH4O)2]	F000 = 916
Mr = 925.37	Dx = 1.866 Mg m−3
Monoclinic, P21/c	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1543 reflections
a = 9.0777 (12) Å	θ = 2.9–29.2º
b = 10.8949 (9) Å	µ = 1.38 mm−1
c = 16.690 (2) Å	T = 298 (2) K
β = 93.847 (10)º	Prism, colorless
V = 1646.9 (3) Å3	0.50 × 0.40 × 0.25 mm
Z = 2

Stoe IPDSII diffractometer	4642 independent reflections
Radiation source: fine-focus sealed tube	4223 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.075
Detector resolution: 0.15 mm pixels mm-1	θmax = 29.8º
T = 298(2) K	θmin = 2.9º
rotation method scans	h = −12→8
Absorption correction: numericalShape of crystal determined optically (X-SHAPE; Stoe & Cie, 2005)	k = −14→10
Tmin = 0.510, Tmax = 0.710	l = −22→19
4664 measured reflections

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)] = 0.062	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.171	w = 1/[σ2(Fo2) + (0.1202P)2 + 2.8103P] where P = (Fo2 + 2Fc2)/3
S = 1.07	(Δ/σ)max = 0.015
4642 reflections	Δρmax = 1.00 e Å−3
239 parameters	Δρmin = −0.95 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

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 > 2sigma(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
Cd1	0.38914 (3)	0.18792 (3)	0.167582 (18)	0.02737 (16)
O1	0.5852 (4)	0.0852 (3)	0.2353 (3)	0.0397 (8)
H1B	0.580 (6)	0.001 (5)	0.233 (3)	0.020 (11)*
O2	0.2968 (5)	0.1892 (3)	0.3010 (3)	0.0391 (9)
O3	0.4556 (4)	0.3323 (3)	0.2788 (2)	0.0359 (8)
O4	0.3358 (5)	0.3363 (5)	0.3875 (3)	0.0502 (10)
O5	0.2209 (6)	0.3467 (5)	0.1596 (3)	0.0541 (10)
O6	0.1241 (9)	0.2195 (8)	0.0768 (8)	0.118 (4)
O7	−0.0039 (8)	0.3728 (10)	0.1114 (5)	0.115 (3)
N1	0.2489 (4)	0.0003 (4)	0.1585 (3)	0.0343 (8)
N2	0.4388 (4)	0.0798 (3)	0.0499 (2)	0.0270 (7)
N3	0.5671 (4)	0.2952 (3)	0.0946 (3)	0.0295 (7)
N4	0.3612 (4)	0.2867 (4)	0.3234 (2)	0.0288 (7)
N5	0.1090 (6)	0.3123 (4)	0.1154 (4)	0.0449 (12)
C1	0.1339 (6)	−0.0214 (5)	0.2045 (4)	0.0440 (12)
H1	0.1363	0.0123	0.2558	0.053*
C2	0.0136 (6)	−0.0917 (6)	0.1781 (4)	0.0482 (14)
H2	−0.0620	−0.1068	0.2117	0.058*
C3	0.0071 (5)	−0.1392 (6)	0.1013 (4)	0.0465 (13)
H3	−0.0750	−0.1838	0.0816	0.056*
C4	0.1251 (5)	−0.1196 (5)	0.0536 (3)	0.0365 (10)
H4	0.1232	−0.1502	0.0016	0.044*
C5	0.2455 (4)	−0.0533 (4)	0.0855 (3)	0.0314 (8)
C6	0.3792 (4)	−0.0321 (4)	0.0401 (3)	0.0264 (8)
C7	0.5546 (4)	0.1162 (4)	0.0106 (3)	0.0258 (7)
C8	0.5956 (4)	0.2482 (4)	0.0224 (3)	0.0279 (8)
C9	0.6505 (5)	0.3192 (4)	−0.0380 (3)	0.0319 (10)
H9	0.6588	0.2868	−0.0890	0.038*
C10	0.6926 (5)	0.4390 (4)	−0.0209 (3)	0.0361 (10)
H10	0.7325	0.4875	−0.0599	0.043*
C11	0.6746 (5)	0.4859 (4)	0.0553 (3)	0.0358 (10)
H11	0.7062	0.5648	0.0689	0.043*
C12	0.6086 (5)	0.4124 (4)	0.1104 (3)	0.0324 (9)
H12	0.5920	0.4451	0.1605	0.039*
C13	0.7367 (7)	0.1300 (6)	0.2397 (5)	0.0525 (14)
H13A	0.7409	0.2093	0.2650	0.063*
H13B	0.7702	0.1366	0.1865	0.063*
H13C	0.7990	0.0738	0.2706	0.063*

	U11	U22	U33	U12	U13	U23
Cd1	0.0283 (2)	0.0260 (2)	0.0286 (2)	0.00137 (9)	0.00796 (15)	−0.00333 (9)
O1	0.0364 (16)	0.0306 (16)	0.052 (2)	0.0038 (13)	0.0046 (16)	0.0021 (15)
O2	0.045 (2)	0.0310 (17)	0.043 (2)	−0.0054 (12)	0.0127 (18)	0.0033 (13)
O3	0.0322 (15)	0.0335 (14)	0.043 (2)	−0.0044 (12)	0.0110 (16)	−0.0079 (14)
O4	0.0327 (17)	0.082 (3)	0.037 (2)	−0.0043 (18)	0.0072 (16)	−0.023 (2)
O5	0.056 (2)	0.056 (2)	0.050 (2)	0.018 (2)	−0.002 (2)	−0.004 (2)
O6	0.090 (5)	0.076 (4)	0.179 (11)	0.014 (4)	−0.058 (6)	−0.043 (6)
O7	0.063 (4)	0.176 (8)	0.107 (6)	0.073 (5)	0.014 (4)	0.038 (6)
N1	0.0264 (16)	0.042 (2)	0.0352 (19)	−0.0026 (14)	0.0116 (16)	−0.0054 (16)
N2	0.0235 (14)	0.0275 (15)	0.0303 (17)	0.0017 (12)	0.0046 (14)	−0.0009 (13)
N3	0.0296 (17)	0.0284 (15)	0.0311 (18)	0.0012 (13)	0.0064 (15)	−0.0029 (14)
N4	0.0234 (15)	0.0354 (16)	0.0279 (17)	−0.0004 (13)	0.0047 (14)	−0.0077 (15)
N5	0.051 (2)	0.091 (3)	0.082 (3)	0.0054 (16)	0.002 (2)	0.015 (2)
C1	0.032 (2)	0.053 (3)	0.050 (3)	−0.005 (2)	0.018 (2)	−0.011 (2)
C2	0.031 (2)	0.055 (3)	0.060 (3)	−0.009 (2)	0.021 (2)	−0.015 (3)
C3	0.028 (2)	0.052 (3)	0.061 (3)	−0.009 (2)	0.012 (2)	−0.013 (3)
C4	0.0243 (17)	0.039 (2)	0.047 (3)	0.0025 (16)	0.0053 (18)	−0.012 (2)
C5	0.0228 (16)	0.036 (2)	0.036 (2)	0.0003 (15)	0.0055 (16)	−0.0057 (18)
C6	0.0229 (16)	0.0293 (18)	0.0275 (18)	0.0006 (13)	0.0050 (15)	−0.0047 (15)
C7	0.0219 (15)	0.0279 (17)	0.0282 (18)	0.0002 (14)	0.0050 (15)	−0.0029 (15)
C8	0.0230 (16)	0.0288 (18)	0.033 (2)	0.0007 (14)	0.0063 (15)	−0.0021 (16)
C9	0.0276 (19)	0.032 (2)	0.037 (2)	−0.0010 (14)	0.0117 (19)	−0.0024 (16)
C10	0.034 (2)	0.032 (2)	0.044 (2)	−0.0045 (17)	0.012 (2)	−0.0003 (19)
C11	0.033 (2)	0.0295 (19)	0.046 (3)	−0.0027 (16)	0.009 (2)	−0.0044 (19)
C12	0.0320 (18)	0.0294 (19)	0.036 (2)	0.0036 (15)	0.0055 (18)	−0.0053 (17)
C13	0.044 (3)	0.051 (3)	0.063 (4)	0.003 (2)	0.008 (3)	0.005 (3)

O1—Cd1	2.330 (4)	C4—H4	0.9300
O1—H1B	0.92 (5)	C5—N1	1.349 (6)
O2—Cd1	2.431 (4)	C5—C6	1.492 (5)
O3—Cd1	2.476 (4)	C6—N2	1.340 (5)
O5—Cd1	2.305 (4)	C6—C7i	1.409 (5)
N1—Cd1	2.407 (4)	C7—N2	1.336 (5)
N2—Cd1	2.359 (4)	C7—C6i	1.409 (5)
N3—Cd1	2.393 (4)	C7—C8	1.495 (6)
N4—O4	1.234 (5)	C8—N3	1.350 (6)
N4—O2	1.257 (5)	C8—C9	1.389 (6)
N4—O3	1.273 (5)	C9—C10	1.385 (6)
N5—O6	1.211 (10)	C9—H9	0.9300
N5—O7	1.217 (7)	C10—C11	1.390 (7)
N5—O5	1.271 (8)	C10—H10	0.9300
C1—N1	1.357 (6)	C11—C12	1.387 (6)
C1—C2	1.382 (8)	C11—H11	0.9300
C1—H1	0.9300	C12—N3	1.352 (6)
C2—C3	1.380 (9)	C12—H12	0.9300
C2—H2	0.9300	C13—O1	1.457 (7)
C3—C4	1.393 (6)	C13—H13A	0.9600
C3—H3	0.9300	C13—H13B	0.9600
C4—C5	1.385 (6)	C13—H13C	0.9600
O5—Cd1—O1	150.47 (16)	N1—C1—C2	122.5 (5)
O5—Cd1—N2	119.29 (16)	N1—C1—H1	118.8
O1—Cd1—N2	88.94 (13)	C2—C1—H1	118.8
O5—Cd1—N3	94.10 (16)	C3—C2—C1	119.2 (5)
O1—Cd1—N3	87.79 (13)	C3—C2—H2	120.4
N2—Cd1—N3	69.31 (13)	C1—C2—H2	120.4
O5—Cd1—N1	106.73 (17)	C2—C3—C4	119.0 (5)
O1—Cd1—N1	90.37 (14)	C2—C3—H3	120.5
N2—Cd1—N1	69.73 (12)	C4—C3—H3	120.5
N3—Cd1—N1	139.02 (13)	C5—C4—C3	118.5 (5)
O5—Cd1—O2	77.34 (15)	C5—C4—H4	120.7
O1—Cd1—O2	81.82 (14)	C3—C4—H4	120.7
N2—Cd1—O2	149.55 (11)	N1—C5—C4	122.8 (4)
N3—Cd1—O2	138.56 (14)	N1—C5—C6	114.9 (4)
N1—Cd1—O2	81.32 (12)	C4—C5—C6	122.2 (4)
O5—Cd1—O3	72.18 (16)	N2—C6—C7i	118.7 (3)
O1—Cd1—O3	78.57 (14)	N2—C6—C5	114.5 (3)
N2—Cd1—O3	152.93 (12)	C7i—C6—C5	126.8 (4)
N3—Cd1—O3	86.13 (13)	N2—C7—C6i	118.9 (4)
N1—Cd1—O3	133.44 (13)	N2—C7—C8	114.7 (3)
O2—Cd1—O3	52.52 (12)	C6i—C7—C8	126.3 (3)
C13—O1—Cd1	123.5 (3)	N3—C8—C9	122.4 (4)
C13—O1—H1B	112 (3)	N3—C8—C7	114.9 (3)
Cd1—O1—H1B	115 (4)	C9—C8—C7	122.6 (4)
N4—O2—Cd1	95.5 (3)	C10—C9—C8	118.9 (5)
N4—O3—Cd1	92.9 (2)	C10—C9—H9	120.6
N5—O5—Cd1	108.2 (4)	C8—C9—H9	120.6
C5—N1—C1	117.6 (4)	C9—C10—C11	119.1 (4)
C5—N1—Cd1	113.9 (3)	C9—C10—H10	120.4
C1—N1—Cd1	122.4 (3)	C11—C10—H10	120.4
C7—N2—C6	122.3 (3)	C12—C11—C10	118.5 (4)
C7—N2—Cd1	117.5 (3)	C12—C11—H11	120.7
C6—N2—Cd1	117.3 (3)	C10—C11—H11	120.7
C8—N3—C12	117.7 (4)	N3—C12—C11	122.8 (4)
C8—N3—Cd1	116.4 (3)	N3—C12—H12	118.6
C12—N3—Cd1	123.4 (3)	C11—C12—H12	118.6
O4—N4—O2	121.2 (4)	O1—C13—H13A	109.5
O4—N4—O3	120.5 (4)	O1—C13—H13B	109.5
O2—N4—O3	118.2 (4)	H13A—C13—H13B	109.5
O6—N5—O7	123.2 (9)	O1—C13—H13C	109.5
O6—N5—O5	116.1 (6)	H13A—C13—H13C	109.5
O7—N5—O5	120.6 (8)	H13B—C13—H13C	109.5
N1—C1—C2—C3	−1.9 (10)	C13—O1—Cd1—N3	19.8 (4)
C1—C2—C3—C4	2.8 (10)	C13—O1—Cd1—N1	158.9 (4)
C2—C3—C4—C5	0.4 (9)	C13—O1—Cd1—O2	−119.9 (4)
C3—C4—C5—N1	−4.9 (8)	C13—O1—Cd1—O3	−66.7 (4)
C3—C4—C5—C6	177.5 (5)	C7—N2—Cd1—O5	94.7 (4)
N1—C5—C6—N2	−36.5 (6)	C6—N2—Cd1—O5	−104.3 (4)
C4—C5—C6—N2	141.4 (5)	C7—N2—Cd1—O1	−76.2 (3)
N1—C5—C6—C7i	143.9 (5)	C6—N2—Cd1—O1	84.8 (3)
C4—C5—C6—C7i	−38.2 (7)	C7—N2—Cd1—N3	11.8 (3)
N2—C7—C8—N3	31.1 (6)	C6—N2—Cd1—N3	172.8 (4)
C6i—C7—C8—N3	−152.5 (4)	C7—N2—Cd1—N1	−167.0 (4)
N2—C7—C8—C9	−145.2 (4)	C6—N2—Cd1—N1	−6.0 (3)
C6i—C7—C8—C9	31.2 (7)	C7—N2—Cd1—O2	−148.0 (3)
N3—C8—C9—C10	7.2 (7)	C6—N2—Cd1—O2	13.0 (5)
C7—C8—C9—C10	−176.8 (5)	C7—N2—Cd1—O3	−14.4 (5)
C8—C9—C10—C11	−2.0 (8)	C6—N2—Cd1—O3	146.6 (3)
C9—C10—C11—C12	−2.9 (8)	C8—N3—Cd1—O5	−114.3 (3)
C10—C11—C12—N3	3.1 (8)	C12—N3—Cd1—O5	47.6 (4)
C4—C5—N1—C1	5.8 (8)	C8—N3—Cd1—O1	95.3 (3)
C6—C5—N1—C1	−176.4 (5)	C12—N3—Cd1—O1	−102.9 (4)
C4—C5—N1—Cd1	−147.4 (4)	C8—N3—Cd1—N2	5.6 (3)
C6—C5—N1—Cd1	30.5 (5)	C12—N3—Cd1—N2	167.4 (4)
C2—C1—N1—C5	−2.4 (9)	C8—N3—Cd1—N1	7.2 (5)
C2—C1—N1—Cd1	148.4 (5)	C12—N3—Cd1—N1	169.1 (4)
C6i—C7—N2—C6	−3.0 (7)	C8—N3—Cd1—O2	170.3 (3)
C8—C7—N2—C6	173.7 (4)	C12—N3—Cd1—O2	−27.9 (5)
C6i—C7—N2—Cd1	157.0 (3)	C8—N3—Cd1—O3	173.9 (3)
C8—C7—N2—Cd1	−26.3 (5)	C12—N3—Cd1—O3	−24.2 (4)
C7i—C6—N2—C7	3.0 (7)	C5—N1—Cd1—O5	102.0 (3)
C5—C6—N2—C7	−176.7 (4)	C1—N1—Cd1—O5	−49.8 (5)
C7i—C6—N2—Cd1	−157.0 (3)	C5—N1—Cd1—O1	−102.5 (3)
C5—C6—N2—Cd1	23.3 (5)	C1—N1—Cd1—O1	105.8 (5)
C9—C8—N3—C12	−7.0 (7)	C5—N1—Cd1—N2	−13.7 (3)
C7—C8—N3—C12	176.7 (4)	C1—N1—Cd1—N2	−165.5 (5)
C9—C8—N3—Cd1	155.9 (4)	C5—N1—Cd1—N3	−15.4 (5)
C7—C8—N3—Cd1	−20.4 (5)	C1—N1—Cd1—N3	−167.2 (4)
C11—C12—N3—C8	1.7 (7)	C5—N1—Cd1—O2	175.9 (4)
C11—C12—N3—Cd1	−159.9 (4)	C1—N1—Cd1—O2	24.1 (5)
O4—N4—O2—Cd1	171.9 (4)	C5—N1—Cd1—O3	−177.0 (3)
O3—N4—O2—Cd1	−9.3 (5)	C1—N1—Cd1—O3	31.3 (5)
O4—N4—O3—Cd1	−172.1 (4)	N4—O2—Cd1—O5	−71.8 (3)
O2—N4—O3—Cd1	9.1 (5)	N4—O2—Cd1—O1	87.1 (3)
O6—N5—O5—Cd1	−12.9 (9)	N4—O2—Cd1—N2	160.8 (3)
O7—N5—O5—Cd1	169.2 (6)	N4—O2—Cd1—N3	9.9 (4)
N5—O5—Cd1—O1	−154.5 (3)	N4—O2—Cd1—N1	178.8 (3)
N5—O5—Cd1—N2	44.2 (4)	N4—O2—Cd1—O3	5.3 (3)
N5—O5—Cd1—N3	112.8 (4)	N4—O3—Cd1—O5	82.3 (3)
N5—O5—Cd1—N1	−31.5 (4)	N4—O3—Cd1—O1	−93.6 (3)
N5—O5—Cd1—O2	−108.3 (4)	N4—O3—Cd1—N2	−157.7 (3)
N5—O5—Cd1—O3	−162.6 (4)	N4—O3—Cd1—N3	177.9 (3)
C13—O1—Cd1—O5	−74.6 (5)	N4—O3—Cd1—N1	−14.1 (4)
C13—O1—Cd1—N2	89.2 (4)	N4—O3—Cd1—O2	−5.2 (3)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1B···O3ii	0.92 (5)	1.87 (5)	2.788 (5)	172

O1—Cd1	2.330 (4)
O2—Cd1	2.431 (4)
O3—Cd1	2.476 (4)
O5—Cd1	2.305 (4)
N1—Cd1	2.407 (4)
N2—Cd1	2.359 (4)
N3—Cd1	2.393 (4)

O5—Cd1—O1	150.47 (16)
O5—Cd1—N2	119.29 (16)
O1—Cd1—N2	88.94 (13)
O5—Cd1—N3	94.10 (16)
O1—Cd1—N3	87.79 (13)
N2—Cd1—N3	69.31 (13)
O5—Cd1—N1	106.73 (17)
O1—Cd1—N1	90.37 (14)
N2—Cd1—N1	69.73 (12)
N3—Cd1—N1	139.02 (13)
O5—Cd1—O2	77.34 (15)
O1—Cd1—O2	81.82 (14)
N2—Cd1—O2	149.55 (11)
N3—Cd1—O2	138.56 (14)
N1—Cd1—O2	81.32 (12)
O5—Cd1—O3	72.18 (16)
O1—Cd1—O3	78.57 (14)
N2—Cd1—O3	152.93 (12)
N3—Cd1—O3	86.13 (13)
N1—Cd1—O3	133.44 (13)
O2—Cd1—O3	52.52 (12)

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1B⋯O3i	0.92 (5)	1.87 (5)	2.788 (5)	172

Symmetry code: (i) .