Dichlorido{N,N-dimethyl-N'-[1-(2-pyrid-yl)ethyl-idene]ethane-1,2-diamine-κN,N',N''}zinc.

The asymmetric unit of the title compound, [ZnCl(2)(C(11)H(17)N(3))], contains two independent penta-coordinate Zn(II) complex mol-ecules. In each mol-ecule, the metal atom is coordinated by an N,N',N''-tridenate Schiff base and two Cl atoms in a distorted square-pyramidal geometry. The two mol-ecules differ little in their geometry, but more in their inter-molecular inter-actions. In the crystal, adjacent mol-ecules are connected via C-H⋯Cl inter-actions into a three-dimensional supra-molecular structure. The network is supplemented by π-π inter-actions formed between the aromatic rings of pairs of the symmetry-related mol-ecules [centroid-centroid distances = 3.6255 (10) and 3.7073 (10) Å]. The crystal lattice contains void spaces with a size of 52 Å(3).

Related literature

For the isotypic Mn(II) complex, see: Ikmal Hisham et al. (2011 ▶). For the crystal structures of similar ZnCl2 complexes, see: Gourbatsis et al. (1999 ▶); Sun (2005 ▶). For a description of the geometry of five-coordinate metal complexes, see: Addison et al. (1984 ▶).

Experimental

Crystal data

[ZnCl2(C11H17N3)]

M = 327.55

Monoclinic,

a = 17.4849 (8) Å

b = 9.8161 (4) Å

c = 20.4264 (7) Å

β = 124.578 (3)°

V = 2886.6 (2) Å3

Z = 8

Mo Kα radiation

μ = 2.05 mm−1

T = 100 K

0.27 × 0.23 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.607, T max = 0.748

20477 measured reflections

6294 independent reflections

5510 reflections with I > 2σ(I)

R int = 0.022

Refinement

R[F 2 > 2σ(F 2)] = 0.021

wR(F 2) = 0.052

S = 1.04

6294 reflections

313 parameters

H-atom parameters constrained

Δρmax = 0.36 e Å−3

Δρmin = −0.28 e Å−3

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: X-SEED (Barbour, 2001 ▶); software used to prepare material for publication: SHELXL97 and publCIF (Westrip, 2010 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811025669/om2444sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811025669/om2444Isup2.hkl

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

[ZnCl2(C11H17N3)]	F(000) = 1344
Mr = 327.55	Dx = 1.507 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9925 reflections
a = 17.4849 (8) Å	θ = 2.4–30.6°
b = 9.8161 (4) Å	µ = 2.05 mm−1
c = 20.4264 (7) Å	T = 100 K
β = 124.578 (3)°	Block, colorless
V = 2886.6 (2) Å3	0.27 × 0.23 × 0.15 mm
Z = 8

Bruker APEXII CCD diffractometer	6294 independent reflections
Radiation source: fine-focus sealed tube	5510 reflections with I > 2σ(I)
graphite	Rint = 0.022
φ and ω scans	θmax = 27.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −22→21
Tmin = 0.607, Tmax = 0.748	k = −12→12
20477 measured reflections	l = −26→26

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.052	H-atom parameters constrained
S = 1.04	w = 1/[σ2(Fo2) + (0.0226P)2 + 0.9433P] where P = (Fo2 + 2Fc2)/3
6294 reflections	(Δ/σ)max = 0.002
313 parameters	Δρmax = 0.36 e Å−3
0 restraints	Δρmin = −0.28 e Å−3

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.

	x	y	z	Uiso*/Ueq
Zn1	0.097383 (12)	0.523307 (18)	0.248455 (10)	0.01180 (5)
Cl1	0.22099 (3)	0.66993 (4)	0.31121 (2)	0.01561 (8)
Cl2	0.14396 (3)	0.31088 (4)	0.23943 (2)	0.01519 (8)
N1	0.03628 (9)	0.60104 (13)	0.12863 (8)	0.0139 (3)
N2	−0.04898 (9)	0.51386 (13)	0.19110 (8)	0.0141 (3)
N3	0.08663 (9)	0.49253 (13)	0.34845 (8)	0.0141 (3)
C1	0.08312 (12)	0.65350 (16)	0.10080 (10)	0.0181 (3)
H1	0.1487	0.6620	0.1358	0.022*
C2	0.03935 (13)	0.69606 (17)	0.02250 (10)	0.0225 (4)
H2	0.0745	0.7317	0.0041	0.027*
C3	−0.05605 (13)	0.68571 (18)	−0.02813 (10)	0.0238 (4)
H3	−0.0876	0.7140	−0.0820	0.029*
C4	−0.10510 (12)	0.63350 (17)	0.00065 (10)	0.0202 (3)
H4	−0.1709	0.6268	−0.0330	0.024*
C5	−0.05711 (11)	0.59111 (16)	0.07919 (9)	0.0156 (3)
C6	−0.10354 (11)	0.53702 (15)	0.11671 (10)	0.0153 (3)
C7	−0.20671 (12)	0.51654 (19)	0.06620 (11)	0.0247 (4)
H7A	−0.2272	0.4868	0.0997	0.037*
H7B	−0.2229	0.4469	0.0259	0.037*
H7C	−0.2375	0.6025	0.0400	0.037*
C8	−0.08002 (11)	0.46662 (16)	0.24024 (10)	0.0161 (3)
H8A	−0.1292	0.3968	0.2113	0.019*
H8B	−0.1056	0.5436	0.2534	0.019*
C9	0.00363 (11)	0.40623 (16)	0.31586 (9)	0.0167 (3)
H9A	−0.0107	0.3962	0.3560	0.020*
H9B	0.0166	0.3145	0.3043	0.020*
C10	0.16872 (11)	0.42164 (17)	0.41521 (9)	0.0196 (3)
H10A	0.2242	0.4774	0.4349	0.029*
H10B	0.1762	0.3336	0.3969	0.029*
H10C	0.1601	0.4069	0.4581	0.029*
C11	0.07513 (12)	0.62345 (17)	0.37716 (10)	0.0186 (3)
H11A	0.0239	0.6745	0.3324	0.028*
H11B	0.1326	0.6765	0.4015	0.028*
H11C	0.0613	0.6065	0.4167	0.028*
Zn2	0.381351 (12)	0.529056 (18)	0.644032 (11)	0.01293 (5)
Cl3	0.34646 (3)	0.30943 (4)	0.59819 (2)	0.01758 (8)
Cl4	0.27052 (3)	0.69499 (4)	0.58273 (2)	0.01882 (9)
N4	0.45804 (9)	0.59876 (13)	0.59532 (8)	0.0145 (3)
N5	0.52234 (9)	0.51339 (13)	0.73866 (8)	0.0130 (3)
N6	0.37431 (9)	0.51154 (13)	0.74869 (8)	0.0163 (3)
C12	0.42130 (12)	0.64614 (16)	0.52195 (10)	0.0182 (3)
H12	0.3558	0.6565	0.4872	0.022*
C13	0.47570 (12)	0.68075 (17)	0.49470 (10)	0.0205 (4)
H13	0.4477	0.7133	0.4420	0.025*
C14	0.57101 (12)	0.66722 (16)	0.54521 (10)	0.0198 (4)
H14	0.6095	0.6906	0.5279	0.024*
C15	0.60962 (11)	0.61874 (16)	0.62199 (10)	0.0161 (3)
H15	0.6750	0.6085	0.6580	0.019*
C16	0.55100 (11)	0.58562 (15)	0.64499 (9)	0.0130 (3)
C17	0.58544 (11)	0.53679 (15)	0.72681 (9)	0.0129 (3)
C18	0.68712 (11)	0.52205 (17)	0.78736 (10)	0.0181 (3)
H18A	0.7152	0.6124	0.8059	0.027*
H18B	0.7153	0.4753	0.7636	0.027*
H18C	0.6978	0.4688	0.8324	0.027*
C19	0.54256 (11)	0.46863 (16)	0.81533 (9)	0.0157 (3)
H19A	0.5678	0.5453	0.8536	0.019*
H19B	0.5891	0.3943	0.8374	0.019*
C20	0.45215 (11)	0.41849 (16)	0.80131 (10)	0.0172 (3)
H20A	0.4377	0.3267	0.7770	0.021*
H20B	0.4595	0.4110	0.8529	0.021*
C21	0.38747 (13)	0.64417 (17)	0.78738 (11)	0.0234 (4)
H21A	0.3349	0.7038	0.7516	0.035*
H21B	0.4451	0.6861	0.7997	0.035*
H21C	0.3912	0.6309	0.8367	0.035*
C22	0.28596 (12)	0.4513 (2)	0.72779 (11)	0.0263 (4)
H22A	0.2878	0.4376	0.7762	0.039*
H22B	0.2766	0.3634	0.7015	0.039*
H22C	0.2346	0.5127	0.6918	0.039*

	U11	U22	U33	U12	U13	U23
Zn1	0.01005 (10)	0.01180 (9)	0.01230 (9)	0.00035 (7)	0.00560 (8)	0.00060 (7)
Cl1	0.01217 (18)	0.01420 (18)	0.01770 (19)	−0.00150 (14)	0.00683 (16)	−0.00033 (14)
Cl2	0.01386 (19)	0.01249 (18)	0.01870 (19)	0.00000 (14)	0.00892 (16)	−0.00121 (14)
N1	0.0130 (7)	0.0136 (7)	0.0141 (6)	0.0031 (5)	0.0071 (6)	0.0012 (5)
N2	0.0132 (7)	0.0117 (6)	0.0175 (7)	0.0005 (5)	0.0088 (6)	−0.0004 (5)
N3	0.0128 (7)	0.0131 (6)	0.0142 (7)	0.0005 (5)	0.0064 (6)	0.0003 (5)
C1	0.0182 (9)	0.0167 (8)	0.0211 (8)	0.0044 (7)	0.0122 (7)	0.0029 (6)
C2	0.0274 (10)	0.0221 (9)	0.0227 (9)	0.0062 (7)	0.0170 (8)	0.0067 (7)
C3	0.0294 (10)	0.0232 (9)	0.0151 (8)	0.0067 (7)	0.0105 (8)	0.0033 (7)
C4	0.0188 (9)	0.0201 (9)	0.0158 (8)	0.0025 (7)	0.0062 (7)	−0.0008 (7)
C5	0.0161 (8)	0.0121 (8)	0.0153 (8)	0.0018 (6)	0.0068 (7)	−0.0023 (6)
C6	0.0137 (8)	0.0114 (7)	0.0179 (8)	0.0003 (6)	0.0072 (7)	−0.0017 (6)
C7	0.0150 (9)	0.0282 (10)	0.0222 (9)	−0.0020 (7)	0.0055 (8)	0.0009 (7)
C8	0.0147 (8)	0.0158 (8)	0.0198 (8)	−0.0029 (6)	0.0109 (7)	−0.0009 (6)
C9	0.0182 (9)	0.0144 (8)	0.0197 (8)	−0.0015 (6)	0.0120 (7)	0.0009 (6)
C10	0.0179 (9)	0.0203 (9)	0.0166 (8)	0.0038 (7)	0.0074 (7)	0.0048 (7)
C11	0.0186 (9)	0.0178 (8)	0.0189 (8)	0.0017 (7)	0.0103 (7)	−0.0035 (7)
Zn2	0.01031 (10)	0.01210 (9)	0.01425 (9)	−0.00008 (7)	0.00570 (8)	−0.00033 (7)
Cl3	0.0177 (2)	0.01292 (18)	0.01780 (19)	−0.00023 (15)	0.00746 (17)	−0.00134 (14)
Cl4	0.0140 (2)	0.01604 (19)	0.02074 (19)	0.00305 (15)	0.00643 (17)	0.00000 (15)
N4	0.0132 (7)	0.0133 (7)	0.0142 (7)	−0.0006 (5)	0.0062 (6)	−0.0007 (5)
N5	0.0126 (7)	0.0121 (6)	0.0138 (6)	0.0007 (5)	0.0071 (6)	0.0003 (5)
N6	0.0143 (7)	0.0154 (7)	0.0205 (7)	−0.0009 (5)	0.0107 (6)	−0.0018 (5)
C12	0.0157 (8)	0.0182 (8)	0.0147 (8)	0.0000 (7)	0.0051 (7)	0.0007 (6)
C13	0.0264 (10)	0.0181 (8)	0.0165 (8)	−0.0003 (7)	0.0118 (8)	0.0021 (6)
C14	0.0253 (9)	0.0179 (8)	0.0221 (9)	−0.0022 (7)	0.0168 (8)	0.0005 (7)
C15	0.0144 (8)	0.0151 (8)	0.0190 (8)	0.0005 (6)	0.0096 (7)	−0.0011 (6)
C16	0.0127 (8)	0.0102 (7)	0.0138 (7)	0.0012 (6)	0.0062 (7)	−0.0009 (6)
C17	0.0117 (8)	0.0097 (7)	0.0142 (8)	−0.0005 (6)	0.0055 (7)	−0.0021 (6)
C18	0.0124 (8)	0.0215 (9)	0.0184 (8)	0.0004 (7)	0.0075 (7)	0.0017 (7)
C19	0.0169 (8)	0.0165 (8)	0.0145 (8)	0.0020 (6)	0.0093 (7)	0.0027 (6)
C20	0.0196 (9)	0.0155 (8)	0.0177 (8)	0.0008 (7)	0.0113 (7)	0.0017 (6)
C21	0.0255 (10)	0.0216 (9)	0.0248 (9)	0.0036 (7)	0.0152 (8)	−0.0044 (7)
C22	0.0199 (10)	0.0327 (10)	0.0310 (10)	−0.0051 (8)	0.0173 (9)	−0.0013 (8)

Zn1—N2	2.1278 (13)	Zn2—N5	2.1044 (13)
Zn1—N3	2.1758 (13)	Zn2—N4	2.1842 (13)
Zn1—N1	2.1785 (13)	Zn2—N6	2.2166 (13)
Zn1—Cl2	2.2837 (4)	Zn2—Cl4	2.2852 (4)
Zn1—Cl1	2.2893 (4)	Zn2—Cl3	2.2910 (4)
N1—C1	1.337 (2)	N4—C12	1.335 (2)
N1—C5	1.351 (2)	N4—C16	1.348 (2)
N2—C6	1.275 (2)	N5—C17	1.2775 (19)
N2—C8	1.4612 (19)	N5—C19	1.4635 (19)
N3—C11	1.473 (2)	N6—C21	1.472 (2)
N3—C9	1.473 (2)	N6—C22	1.473 (2)
N3—C10	1.477 (2)	N6—C20	1.477 (2)
C1—C2	1.389 (2)	C12—C13	1.390 (2)
C1—H1	0.9500	C12—H12	0.9500
C2—C3	1.380 (3)	C13—C14	1.381 (2)
C2—H2	0.9500	C13—H13	0.9500
C3—C4	1.384 (2)	C14—C15	1.393 (2)
C3—H3	0.9500	C14—H14	0.9500
C4—C5	1.387 (2)	C15—C16	1.387 (2)
C4—H4	0.9500	C15—H15	0.9500
C5—C6	1.495 (2)	C16—C17	1.498 (2)
C6—C7	1.499 (2)	C17—C18	1.488 (2)
C7—H7A	0.9800	C18—H18A	0.9800
C7—H7B	0.9800	C18—H18B	0.9800
C7—H7C	0.9800	C18—H18C	0.9800
C8—C9	1.521 (2)	C19—C20	1.520 (2)
C8—H8A	0.9900	C19—H19A	0.9900
C8—H8B	0.9900	C19—H19B	0.9900
C9—H9A	0.9900	C20—H20A	0.9900
C9—H9B	0.9900	C20—H20B	0.9900
C10—H10A	0.9800	C21—H21A	0.9800
C10—H10B	0.9800	C21—H21B	0.9800
C10—H10C	0.9800	C21—H21C	0.9800
C11—H11A	0.9800	C22—H22A	0.9800
C11—H11B	0.9800	C22—H22B	0.9800
C11—H11C	0.9800	C22—H22C	0.9800
N2—Zn1—N3	78.06 (5)	N5—Zn2—N4	74.89 (5)
N2—Zn1—N1	74.15 (5)	N5—Zn2—N6	77.63 (5)
N3—Zn1—N1	148.73 (5)	N4—Zn2—N6	148.01 (5)
N2—Zn1—Cl2	106.76 (4)	N5—Zn2—Cl4	137.94 (4)
N3—Zn1—Cl2	100.01 (4)	N4—Zn2—Cl4	94.36 (4)
N1—Zn1—Cl2	101.48 (3)	N6—Zn2—Cl4	95.15 (4)
N2—Zn1—Cl1	142.56 (4)	N5—Zn2—Cl3	102.01 (4)
N3—Zn1—Cl1	96.82 (4)	N4—Zn2—Cl3	101.45 (4)
N1—Zn1—Cl1	96.55 (4)	N6—Zn2—Cl3	99.99 (4)
Cl2—Zn1—Cl1	110.650 (15)	Cl4—Zn2—Cl3	120.032 (16)
C1—N1—C5	118.83 (14)	C12—N4—C16	119.00 (13)
C1—N1—Zn1	125.76 (11)	C12—N4—Zn2	126.29 (11)
C5—N1—Zn1	115.39 (10)	C16—N4—Zn2	114.65 (10)
C6—N2—C8	123.84 (14)	C17—N5—C19	123.13 (14)
C6—N2—Zn1	120.07 (11)	C17—N5—Zn2	120.03 (11)
C8—N2—Zn1	115.79 (10)	C19—N5—Zn2	116.78 (10)
C11—N3—C9	111.07 (12)	C21—N6—C22	109.24 (13)
C11—N3—C10	108.91 (12)	C21—N6—C20	110.95 (13)
C9—N3—C10	109.76 (12)	C22—N6—C20	110.13 (13)
C11—N3—Zn1	110.89 (9)	C21—N6—Zn2	111.83 (10)
C9—N3—Zn1	104.09 (9)	C22—N6—Zn2	112.01 (11)
C10—N3—Zn1	112.07 (10)	C20—N6—Zn2	102.55 (9)
N1—C1—C2	122.36 (16)	N4—C12—C13	122.15 (16)
N1—C1—H1	118.8	N4—C12—H12	118.9
C2—C1—H1	118.8	C13—C12—H12	118.9
C3—C2—C1	118.86 (16)	C14—C13—C12	119.16 (15)
C3—C2—H2	120.6	C14—C13—H13	120.4
C1—C2—H2	120.6	C12—C13—H13	120.4
C2—C3—C4	119.06 (16)	C13—C14—C15	118.84 (15)
C2—C3—H3	120.5	C13—C14—H14	120.6
C4—C3—H3	120.5	C15—C14—H14	120.6
C3—C4—C5	119.25 (16)	C16—C15—C14	118.83 (15)
C3—C4—H4	120.4	C16—C15—H15	120.6
C5—C4—H4	120.4	C14—C15—H15	120.6
N1—C5—C4	121.63 (15)	N4—C16—C15	122.01 (14)
N1—C5—C6	114.84 (13)	N4—C16—C17	114.84 (13)
C4—C5—C6	123.48 (15)	C15—C16—C17	123.13 (14)
N2—C6—C5	114.69 (14)	N5—C17—C18	125.30 (14)
N2—C6—C7	126.21 (15)	N5—C17—C16	115.18 (14)
C5—C6—C7	119.10 (14)	C18—C17—C16	119.51 (13)
C6—C7—H7A	109.5	C17—C18—H18A	109.5
C6—C7—H7B	109.5	C17—C18—H18B	109.5
H7A—C7—H7B	109.5	H18A—C18—H18B	109.5
C6—C7—H7C	109.5	C17—C18—H18C	109.5
H7A—C7—H7C	109.5	H18A—C18—H18C	109.5
H7B—C7—H7C	109.5	H18B—C18—H18C	109.5
N2—C8—C9	107.67 (12)	N5—C19—C20	107.57 (13)
N2—C8—H8A	110.2	N5—C19—H19A	110.2
C9—C8—H8A	110.2	C20—C19—H19A	110.2
N2—C8—H8B	110.2	N5—C19—H19B	110.2
C9—C8—H8B	110.2	C20—C19—H19B	110.2
H8A—C8—H8B	108.5	H19A—C19—H19B	108.5
N3—C9—C8	111.57 (13)	N6—C20—C19	111.55 (13)
N3—C9—H9A	109.3	N6—C20—H20A	109.3
C8—C9—H9A	109.3	C19—C20—H20A	109.3
N3—C9—H9B	109.3	N6—C20—H20B	109.3
C8—C9—H9B	109.3	C19—C20—H20B	109.3
H9A—C9—H9B	108.0	H20A—C20—H20B	108.0
N3—C10—H10A	109.5	N6—C21—H21A	109.5
N3—C10—H10B	109.5	N6—C21—H21B	109.5
H10A—C10—H10B	109.5	H21A—C21—H21B	109.5
N3—C10—H10C	109.5	N6—C21—H21C	109.5
H10A—C10—H10C	109.5	H21A—C21—H21C	109.5
H10B—C10—H10C	109.5	H21B—C21—H21C	109.5
N3—C11—H11A	109.5	N6—C22—H22A	109.5
N3—C11—H11B	109.5	N6—C22—H22B	109.5
H11A—C11—H11B	109.5	H22A—C22—H22B	109.5
N3—C11—H11C	109.5	N6—C22—H22C	109.5
H11A—C11—H11C	109.5	H22A—C22—H22C	109.5
H11B—C11—H11C	109.5	H22B—C22—H22C	109.5

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···Cl2i	0.95	2.79	3.6690 (17)	155
C8—H8A···Cl1ii	0.99	2.63	3.5668 (16)	158
C8—H8B···Cl2iii	0.99	2.73	3.6564 (16)	156
C11—H11A···Cl2iii	0.98	2.77	3.6573 (17)	151
C15—H15···Cl2iv	0.95	2.74	3.6347 (17)	157
C18—H18B···Cl1iv	0.98	2.75	3.7227 (17)	175
C19—H19B···Cl4v	0.99	2.82	3.8089 (16)	174

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯Cl2i	0.95	2.79	3.6690 (17)	155
C8—H8A⋯Cl1ii	0.99	2.63	3.5668 (16)	158
C8—H8B⋯Cl2iii	0.99	2.73	3.6564 (16)	156
C11—H11A⋯Cl2iii	0.98	2.77	3.6573 (17)	151
C15—H15⋯Cl2iv	0.95	2.74	3.6347 (17)	157
C18—H18B⋯Cl1iv	0.98	2.75	3.7227 (17)	175
C19—H19B⋯Cl4v	0.99	2.82	3.8089 (16)	174

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) .