Crystal structure and Hirshfeld surface analysis of one-dimensional copper(II) coordination polymer incorporating succinate and tetra­methyl­ethylene­diamine ligands

The title compound, {[Cu(succ)(tmeda)]·4H₂O}_n, consists of one-dimensional polymeric chains in which the central metal atom is coordinated in a distorted square-planar geometry by one oxygen atom each from two succ ligands and two TMEDA ligand nitro­gen atoms.

Key indicators

Structure: I

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.003 Å
• Disorder in main residue
• R factor = 0.034
• wR factor = 0.091
• Data-to-parameter ratio = 14.7

checkCIF/PLATON results

No syntax errors found



Datablock: I


Alert level B
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Cu1      --O2       .       13.9 s.u.

Alert level C
PLAT193_ALERT_1_C Cell and Diffraction Temperatures Differ by ....          3 Degree
PLAT220_ALERT_2_C NonSolvent Resd 1  C   Ueq(max) / Ueq(min) Range        3.5 Ratio
PLAT241_ALERT_2_C High   'MainMol' Ueq as Compared to Neighbors of         O2 Check
PLAT242_ALERT_2_C Low    'MainMol' Ueq as Compared to Neighbors of         N1 Check
PLAT242_ALERT_2_C Low    'MainMol' Ueq as Compared to Neighbors of         N2 Check
PLAT260_ALERT_2_C Large Average Ueq of Residue Including        O5      0.101 Check
PLAT260_ALERT_2_C Large Average Ueq of Residue Including        O7      0.101 Check
PLAT906_ALERT_3_C Large K Value in the Analysis of Variance ......      4.380 Check
PLAT978_ALERT_2_C Number C-C Bonds with Positive Residual Density.          0 Info

Alert level G
PLAT002_ALERT_2_G Number of Distance or Angle Restraints on AtSite         12 Note
PLAT004_ALERT_5_G Polymeric Structure Found with Maximum Dimension          1 Info
PLAT063_ALERT_4_G Crystal Size Possibly too Large for Beam Size ..       0.61 mm
PLAT172_ALERT_4_G The CIF-Embedded .res File Contains DFIX Records         10 Report
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Cu1      --O1       .        6.2 s.u.
PLAT232_ALERT_2_G Hirshfeld Test Diff (M-X)  Cu1      --O4_a     .        6.5 s.u.
PLAT301_ALERT_3_G Main Residue  Disorder ..............(Resd  1  )        12% Note
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          4 Note
PLAT802_ALERT_4_G CIF Input Record(s) with more than 80 Characters          5 Info
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............         10 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   1 ALERT level B = A potentially serious problem, consider carefully
   9 ALERT level C = Check. Ensure it is not caused by an omission or oversight
  10 ALERT level G = General information/check it is not something unexpected

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
  11 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

---

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA (Stoe & Cie, 2002); data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXT2017/1 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

catena-Poly[[[(N,N,N',N'-tetramethylethylenediamine-κ²N,N')copper(II)]-µ-succinato-κ²O¹:O⁴] tetrahydrate]

Crystal data

[Cu(C4H4O4)(C6H16N2)]·4H2O	F(000) = 780
Mr = 367.88	Dx = 1.403 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 7.1195 (4) Å	Cell parameters from 19036 reflections
b = 12.3172 (6) Å	θ = 1.7–29.9°
c = 19.8590 (12) Å	µ = 1.29 mm^−1
β = 91.160 (5)°	T = 296 K
V = 1741.12 (17) Å^3	Stick, blue
Z = 4	0.61 × 0.33 × 0.17 mm

Data collection

Stoe IPDS 2 diffractometer	2864 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	Rint = 0.033
rotation method scans	θmax = 26.0°, θmin = 2.0°
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	h = −8→8
Tmin = 0.645, Tmax = 0.810	k = −14→15
12278 measured reflections	l = −24→24
3427 independent reflections

Refinement

Refinement on F^2	10 restraints
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.034	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.091	w = 1/[σ^2(Fo^2) + (0.056P)^2 + 0.2662P] where P = (Fo^2 + 2Fc^2)/3
S = 1.04	(Δ/σ)max = 0.001
3427 reflections	Δρmax = 0.28 e Å^−3
233 parameters	Δρmin = −0.26 e Å^−3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cu1	0.21554 (4)	0.28617 (2)	0.62467 (2)	0.03940 (11)
O1	0.3640 (2)	0.41083 (14)	0.59461 (8)	0.0471 (4)
O2	0.5331 (3)	0.34615 (16)	0.67869 (10)	0.0581 (5)
O3	1.0718 (2)	0.38395 (14)	0.68503 (8)	0.0457 (4)
O4	0.9260 (3)	0.37395 (14)	0.58714 (8)	0.0512 (4)
O7	0.6289 (4)	0.3189 (3)	0.81373 (13)	0.1013 (10)
H7A	0.604 (7)	0.321 (5)	0.7735 (10)	0.152*
H7B	0.535 (4)	0.302 (4)	0.834 (2)	0.152*
O8	0.9959 (4)	0.3821 (3)	0.82634 (12)	0.0839 (7)
H8C	1.023 (7)	0.387 (4)	0.7861 (12)	0.126*
H8D	0.892 (4)	0.353 (4)	0.826 (3)	0.126*
N1	0.1142 (4)	0.14824 (18)	0.66575 (12)	0.0592 (6)
N2	0.3026 (3)	0.19183 (18)	0.54703 (11)	0.0545 (5)
C1	0.2261 (7)	0.1220 (4)	0.7259 (2)	0.1078 (15)
H1A	0.356188	0.117338	0.714512	0.129*	0.495 (18)
H1B	0.210105	0.177807	0.759095	0.129*	0.495 (18)
H1C	0.185516	0.053701	0.743793	0.129*	0.495 (18)
H1D	0.145018	0.115226	0.763755	0.129*	0.505 (18)
H1E	0.291101	0.054757	0.719171	0.129*	0.505 (18)
H1F	0.315690	0.178863	0.734474	0.129*	0.505 (18)
C2	−0.0839 (5)	0.1548 (3)	0.6849 (3)	0.1029 (15)
H2A	−0.160188	0.172027	0.645981	0.124*	0.505 (18)
H2B	−0.122672	0.086297	0.703029	0.124*	0.505 (18)
H2C	−0.098082	0.210404	0.718331	0.124*	0.505 (18)
H2D	−0.093773	0.140458	0.732246	0.124*	0.495 (18)
H2E	−0.131289	0.226188	0.675199	0.124*	0.495 (18)
H2F	−0.155879	0.102082	0.659896	0.124*	0.495 (18)
C3	0.086 (3)	0.0712 (12)	0.6087 (8)	0.085 (4)	0.495 (18)
H3A	−0.018047	0.093743	0.579712	0.102*	0.495 (18)
H3B	0.062106	−0.001667	0.624964	0.102*	0.495 (18)
C3A	0.179 (2)	0.0582 (10)	0.6193 (8)	0.077 (3)	0.505 (18)
H3AA	0.302001	0.033292	0.633975	0.093*	0.505 (18)
H3AB	0.092507	−0.002668	0.622077	0.093*	0.505 (18)
C4	0.276 (3)	0.0761 (8)	0.5704 (6)	0.079 (3)	0.495 (18)
H4A	0.378964	0.054535	0.600078	0.095*	0.495 (18)
H4B	0.271645	0.027282	0.532075	0.095*	0.495 (18)
C4A	0.187 (2)	0.0950 (11)	0.5496 (7)	0.087 (4)	0.505 (18)
H4AA	0.239477	0.038474	0.521768	0.105*	0.505 (18)
H4AB	0.060916	0.111090	0.532601	0.105*	0.505 (18)
C5	0.2202 (9)	0.2343 (5)	0.4859 (2)	0.144 (3)
H5A	0.086425	0.238681	0.490305	0.173*	0.495 (18)
H5B	0.269870	0.305336	0.477526	0.173*	0.495 (18)
H5C	0.249344	0.187114	0.449077	0.173*	0.495 (18)
H5D	0.317334	0.248739	0.454300	0.173*	0.505 (18)
H5E	0.133889	0.182085	0.467080	0.173*	0.505 (18)
H5F	0.154415	0.300307	0.495528	0.173*	0.505 (18)
C6	0.5040 (6)	0.1852 (4)	0.5403 (3)	0.1154 (17)
H6A	0.559369	0.156878	0.581131	0.138*	0.505 (18)
H6B	0.533023	0.138122	0.503435	0.138*	0.505 (18)
H6C	0.553549	0.256345	0.531883	0.138*	0.505 (18)
H6D	0.537925	0.210685	0.496501	0.138*	0.495 (18)
H6E	0.564271	0.229441	0.574198	0.138*	0.495 (18)
H6F	0.543745	0.111219	0.545750	0.138*	0.495 (18)
C7	0.5046 (3)	0.41647 (19)	0.63531 (12)	0.0424 (5)
C8	0.6324 (4)	0.51218 (19)	0.62714 (14)	0.0484 (6)
H8A	0.566631	0.577064	0.641138	0.058*
H8B	0.659682	0.520189	0.579733	0.058*
C9	0.8161 (4)	0.5050 (2)	0.66639 (14)	0.0510 (6)
H9A	0.882166	0.573443	0.662250	0.061*
H9B	0.789224	0.494519	0.713636	0.061*
C10	0.9432 (3)	0.41491 (19)	0.64394 (12)	0.0409 (5)
O5	0.7915 (5)	0.3966 (2)	0.45643 (13)	0.1012 (10)
H5G	0.751 (8)	0.454 (3)	0.443 (3)	0.152*
H5H	0.827 (8)	0.399 (5)	0.4946 (13)	0.152*
O6	0.8144 (4)	0.2050 (2)	0.39169 (17)	0.0906 (8)
H6G	0.801 (7)	0.263 (3)	0.411 (2)	0.136*
H6H	0.715 (5)	0.197 (4)	0.369 (2)	0.136*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.03491 (16)	0.04272 (17)	0.04064 (16)	0.00251 (12)	0.00232 (10)	0.00379 (11)
O1	0.0359 (9)	0.0524 (9)	0.0529 (9)	0.0013 (7)	−0.0021 (7)	0.0085 (7)
O2	0.0532 (11)	0.0621 (11)	0.0589 (11)	−0.0009 (9)	−0.0042 (8)	0.0186 (9)
O3	0.0373 (9)	0.0555 (10)	0.0443 (9)	0.0048 (7)	−0.0012 (7)	−0.0012 (7)
O4	0.0481 (10)	0.0573 (10)	0.0482 (9)	0.0097 (8)	−0.0044 (7)	−0.0052 (8)
O7	0.0633 (15)	0.182 (3)	0.0581 (14)	−0.0182 (18)	−0.0042 (11)	0.0190 (17)
O8	0.0686 (15)	0.124 (2)	0.0586 (12)	−0.0156 (14)	−0.0081 (11)	0.0052 (14)
N1	0.0668 (15)	0.0447 (11)	0.0665 (14)	0.0005 (11)	0.0140 (11)	0.0083 (10)
N2	0.0558 (13)	0.0586 (13)	0.0494 (12)	0.0057 (10)	0.0066 (10)	−0.0055 (10)
C1	0.115 (3)	0.107 (3)	0.101 (3)	0.013 (3)	−0.002 (2)	0.059 (3)
C2	0.068 (2)	0.078 (2)	0.164 (4)	−0.0142 (19)	0.028 (2)	0.037 (3)
C3	0.101 (10)	0.061 (6)	0.095 (7)	−0.012 (7)	0.034 (8)	−0.005 (5)
C3A	0.076 (7)	0.045 (4)	0.112 (8)	0.000 (5)	0.020 (7)	0.004 (4)
C4	0.116 (10)	0.055 (4)	0.069 (6)	0.017 (5)	0.026 (6)	−0.002 (4)
C4A	0.096 (8)	0.066 (6)	0.100 (8)	−0.023 (5)	0.011 (6)	−0.031 (6)
C5	0.208 (6)	0.169 (5)	0.055 (2)	0.100 (5)	−0.035 (3)	−0.033 (3)
C6	0.067 (2)	0.148 (4)	0.132 (4)	0.014 (3)	0.026 (2)	−0.067 (3)
C7	0.0361 (12)	0.0459 (12)	0.0453 (12)	0.0079 (10)	0.0072 (9)	0.0023 (10)
C8	0.0395 (13)	0.0412 (12)	0.0646 (15)	0.0047 (10)	0.0023 (11)	0.0016 (11)
C9	0.0414 (13)	0.0450 (13)	0.0664 (16)	0.0019 (11)	−0.0021 (11)	−0.0103 (11)
C10	0.0337 (12)	0.0433 (11)	0.0459 (12)	−0.0035 (9)	0.0034 (9)	0.0006 (10)
O5	0.170 (3)	0.0614 (13)	0.0705 (15)	0.0345 (16)	−0.0484 (17)	−0.0091 (12)
O6	0.0686 (16)	0.0971 (19)	0.106 (2)	0.0074 (14)	0.0017 (13)	−0.0434 (15)

Geometric parameters (Å, º)

Cu1—O1	1.9639 (17)	C3—H3A	0.9700
Cu1—O3^i	1.9958 (16)	C3—H3B	0.9700
Cu1—O4^i	2.4315 (17)	C3—C4	1.56 (2)
Cu1—N1	2.024 (2)	C3A—H3AA	0.9700
Cu1—N2	2.038 (2)	C3A—H3AB	0.9700
Cu1—C10^i	2.540 (2)	C3A—C4A	1.46 (2)
O1—C7	1.275 (3)	C4—H4A	0.9700
O2—C7	1.236 (3)	C4—H4B	0.9700
O3—C10	1.273 (3)	C4A—H4AA	0.9700
O4—C10	1.239 (3)	C4A—H4AB	0.9700
O7—H7A	0.815 (19)	C5—H5A	0.9600
O7—H7B	0.812 (10)	C5—H5B	0.9600
O8—H8C	0.828 (19)	C5—H5C	0.9600
O8—H8D	0.827 (19)	C5—H5D	0.9600
N1—C1	1.459 (5)	C5—H5E	0.9600
N1—C2	1.470 (4)	C5—H5F	0.9600
N1—C3	1.489 (14)	C6—H6A	0.9600
N1—C3A	1.520 (14)	C6—H6B	0.9600
N2—C4	1.513 (10)	C6—H6C	0.9600
N2—C4A	1.453 (11)	C6—H6D	0.9600
N2—C5	1.436 (5)	C6—H6E	0.9600
N2—C6	1.445 (4)	C6—H6F	0.9600
C1—H1A	0.9600	C7—C8	1.500 (3)
C1—H1B	0.9600	C8—H8A	0.9700
C1—H1C	0.9600	C8—H8B	0.9700
C1—H1D	0.9600	C8—C9	1.512 (3)
C1—H1E	0.9600	C9—H9A	0.9700
C1—H1F	0.9600	C9—H9B	0.9700
C2—H2A	0.9600	C9—C10	1.504 (3)
C2—H2B	0.9600	O5—H5G	0.80 (2)
C2—H2C	0.9600	O5—H5H	0.794 (19)
C2—H2D	0.9600	O6—H6G	0.821 (19)
C2—H2E	0.9600	O6—H6H	0.835 (19)
C2—H2F	0.9600
O1—Cu1—O3^i	89.80 (7)	C4—C3—H3B	111.0
O1—Cu1—O4^i	91.00 (7)	N1—C3A—H3AA	109.3
O1—Cu1—N1	167.77 (9)	N1—C3A—H3AB	109.3
O1—Cu1—N2	92.40 (8)	H3AA—C3A—H3AB	108.0
O1—Cu1—C10^i	88.56 (7)	C4A—C3A—N1	111.5 (11)
O3^i—Cu1—O4^i	58.26 (6)	C4A—C3A—H3AA	109.3
O3^i—Cu1—N1	94.20 (8)	C4A—C3A—H3AB	109.3
O3^i—Cu1—N2	165.06 (8)	N2—C4—C3	107.6 (10)
O3^i—Cu1—C10^i	29.61 (7)	N2—C4—H4A	110.2
O4^i—Cu1—C10^i	28.77 (6)	N2—C4—H4B	110.2
N1—Cu1—O4^i	100.93 (8)	C3—C4—H4A	110.2
N1—Cu1—N2	86.72 (9)	C3—C4—H4B	110.2
N1—Cu1—C10^i	100.59 (9)	H4A—C4—H4B	108.5
N2—Cu1—O4^i	106.90 (8)	N2—C4A—C3A	108.8 (11)
N2—Cu1—C10^i	135.64 (9)	N2—C4A—H4AA	109.9
C7—O1—Cu1	105.67 (14)	N2—C4A—H4AB	109.9
C10—O3—Cu1^ii	99.60 (14)	C3A—C4A—H4AA	109.9
C10—O4—Cu1^ii	80.46 (14)	C3A—C4A—H4AB	109.9
H7A—O7—H7B	109 (2)	H4AA—C4A—H4AB	108.3
H8C—O8—H8D	105 (5)	N2—C5—H5A	109.5
C1—N1—Cu1	108.8 (2)	N2—C5—H5B	109.5
C1—N1—C2	108.1 (3)	N2—C5—H5C	109.5
C1—N1—C3	123.0 (8)	H5A—C5—H5B	109.5
C1—N1—C3A	99.7 (6)	H5A—C5—H5C	109.5
C2—N1—Cu1	114.2 (2)	H5B—C5—H5C	109.5
C2—N1—C3	96.8 (7)	H5D—C5—H5E	109.5
C2—N1—C3A	120.0 (6)	H5D—C5—H5F	109.5
C3—N1—Cu1	105.8 (5)	H5E—C5—H5F	109.5
C3A—N1—Cu1	104.7 (5)	N2—C6—H6A	109.5
C4—N2—Cu1	105.2 (4)	N2—C6—H6B	109.5
C4A—N2—Cu1	105.0 (5)	N2—C6—H6C	109.5
C5—N2—Cu1	107.9 (2)	H6A—C6—H6B	109.5
C5—N2—C4	123.4 (8)	H6A—C6—H6C	109.5
C5—N2—C4A	96.1 (8)	H6B—C6—H6C	109.5
C5—N2—C6	109.4 (4)	H6D—C6—H6E	109.5
C6—N2—Cu1	114.8 (2)	H6D—C6—H6F	109.5
C6—N2—C4	96.2 (7)	H6E—C6—H6F	109.5
C6—N2—C4A	121.6 (7)	O1—C7—C8	116.4 (2)
N1—C1—H1A	109.5	O2—C7—O1	121.3 (2)
N1—C1—H1B	109.5	O2—C7—C8	122.3 (2)
N1—C1—H1C	109.5	C7—C8—H8A	108.6
H1A—C1—H1B	109.5	C7—C8—H8B	108.6
H1A—C1—H1C	109.5	C7—C8—C9	114.7 (2)
H1B—C1—H1C	109.5	H8A—C8—H8B	107.6
H1D—C1—H1E	109.5	C9—C8—H8A	108.6
H1D—C1—H1F	109.5	C9—C8—H8B	108.6
H1E—C1—H1F	109.5	C8—C9—H9A	108.7
N1—C2—H2A	109.5	C8—C9—H9B	108.7
N1—C2—H2B	109.5	H9A—C9—H9B	107.6
N1—C2—H2C	109.5	C10—C9—C8	114.2 (2)
H2A—C2—H2B	109.5	C10—C9—H9A	108.7
H2A—C2—H2C	109.5	C10—C9—H9B	108.7
H2B—C2—H2C	109.5	O3—C10—Cu1^ii	50.79 (11)
H2D—C2—H2E	109.5	O3—C10—C9	117.4 (2)
H2D—C2—H2F	109.5	O4—C10—Cu1^ii	70.77 (13)
H2E—C2—H2F	109.5	O4—C10—O3	121.2 (2)
N1—C3—H3A	111.0	O4—C10—C9	121.4 (2)
N1—C3—H3B	111.0	C9—C10—Cu1^ii	166.01 (17)
N1—C3—C4	104.0 (13)	H5G—O5—H5H	113 (5)
H3A—C3—H3B	109.0	H6G—O6—H6H	105 (3)
C4—C3—H3A	111.0
Cu1—O1—C7—O2	5.8 (3)	N1—C3A—C4A—N2	54.0 (19)
Cu1—O1—C7—C8	−174.58 (16)	C1—N1—C3—C4	−76.7 (11)
Cu1^ii—O3—C10—O4	7.5 (3)	C1—N1—C3A—C4A	−145.2 (12)
Cu1^ii—O3—C10—C9	−171.00 (18)	C2—N1—C3—C4	166.6 (11)
Cu1^ii—O4—C10—O3	−6.2 (2)	C2—N1—C3A—C4A	97.2 (12)
Cu1^ii—O4—C10—C9	172.3 (2)	C5—N2—C4—C3	−84.0 (12)
Cu1—N1—C3—C4	49.0 (13)	C5—N2—C4A—C3A	−155.7 (13)
Cu1—N1—C3A—C4A	−32.7 (14)	C6—N2—C4—C3	157.9 (13)
Cu1—N2—C4—C3	40.1 (15)	C6—N2—C4A—C3A	87.1 (12)
Cu1—N2—C4A—C3A	−45.4 (15)	C7—C8—C9—C10	65.1 (3)
O1—C7—C8—C9	−168.5 (2)	C8—C9—C10—Cu1^ii	169.4 (6)
O2—C7—C8—C9	11.1 (3)	C8—C9—C10—O3	−160.5 (2)
N1—C3—C4—N2	−60.5 (18)	C8—C9—C10—O4	20.9 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5H···O4	0.79 (2)	1.98 (2)	2.763 (3)	169 (6)
O6—H6G···O5	0.82 (2)	1.88 (2)	2.694 (3)	175 (5)
O7—H7A···O2	0.82 (2)	1.96 (2)	2.774 (3)	172 (6)
O8—H8C···O3	0.83 (2)	2.04 (2)	2.869 (3)	173 (5)
O8—H8D···O7	0.83 (2)	1.93 (2)	2.733 (4)	165 (5)
O7—H7B···O6^iii	0.81 (1)	1.97 (2)	2.763 (4)	167 (6)
O5—H5G···O1^iv	0.80 (2)	2.00 (2)	2.799 (3)	176 (6)
O6—H6H···O8^v	0.84 (2)	2.01 (2)	2.803 (4)	157 (5)

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