3-Carbamoyl-1-(2-nitrobenzyl)pyridin­ium bromide

Kim, K.B.; Jung, K.-D.; Kim, C.; Kim, Y.

doi:10.1107/S1600536812015917

organic compounds

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ISSN: 2056-9890

Volume 68| Part 5| May 2012| Pages o1441-o1442

doi:10.1107/S1600536812015917

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3-Carbamoyl-1-(2-nitrobenzyl)pyridinium bromide

Kyung Beom Kim,^a Kwang-Deog Jung,^b Cheal Kim ^a ^* and Youngmee Kim ^c ^*

^aDepartment of Fine Chemistry, Seoul National University of Science & Technology, Seoul 139-743, Republic of Korea, ^bClean Energy Research Center, Korea Institute of Science & Technology, Seoul 130-650, Republic of Korea, and ^cDepartment of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Republic of Korea
^*Correspondence e-mail: chealkim@seoultech.ac.kr, ymeekim@ewha.ac.kr

(Received 3 April 2012; accepted 12 April 2012; online 18 April 2012)

In the title compound, C₁₃H₁₂N₃O₃⁺·Br⁻, the benzene and pyridinium rings form a dihedral angle of 82.0 (1)°. In the crystal, N—H⋯Br and N—H⋯O hydrogen bonds link the components into chains along [001]. In addition, weak C—H⋯O and C—H⋯Br hydrogen bonds are observed.

Related literature

The title compound was prepared as an NAD⁺ (nicotinamide adenine dinucleotide) model. For effective regeneration systems for co-enzymes (e.g. NADH), see: Hollmann et al. (2001 ); Lee et al. (2011 ); Maenaka et al. (2012 ); Park et al. (2008 ); Ruppert et al. (1988 ); Zhu et al. (2006 ). For the mechanisms of redox interconversions (NADH/NAD⁺), see: Zhu et al. (2003 ); Song et al. (2008 ).

Experimental

Crystal data

C₁₃H₁₂N₃O₃⁺·Br⁻
M_r = 338.17
Monoclinic, P 2₁ /c
a = 17.576 (4) Å
b = 7.9990 (16) Å
c = 10.152 (2) Å
β = 105.88 (3)°
V = 1372.8 (5) Å³
Z = 4
Mo Kα radiation
μ = 3.01 mm⁻¹
T = 293 K
0.15 × 0.15 × 0.10 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 1997 ) T_min = 0.661, T_max = 0.753
7399 measured reflections
2684 independent reflections
2081 reflections with I > 2σ(I)
R_int = 0.034

Refinement

R[F² > 2σ(F²)] = 0.036
wR(F²) = 0.086
S = 1.04
2684 reflections
187 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.36 e Å⁻³
Δρ_min = −0.38 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1B⋯O1ⁱ	0.86 (1)	2.30 (1)	3.143 (4)	168 (4)
N1—H1A⋯Br1ⁱⁱ	0.86 (1)	2.61 (1)	3.454 (3)	166 (3)
C4—H4⋯Br1	0.93	2.82	3.743 (3)	173
C7—H7B⋯Br1ⁱⁱⁱ	0.97	2.82	3.595 (3)	137
C5—H5⋯O2^iv	0.93	2.36	3.271 (4)	167
C3—H3⋯O1ⁱ	0.93	2.27	3.150 (4)	157
Symmetry codes: (i) $[x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) $[-x+1, y-{\script{1\over 2}}, -z+{\script{3\over 2}}]$ ; (iii) x, y, z+1; (iv) $[x, -y+{\script{3\over 2}}, z-{\script{1\over 2}}]$ .

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812015917/lh5450sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812015917/lh5450Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536812015917/lh5450Isup3.cml

checkCIF report

Comment top

One of the most important challenges in applying mono-oxygenases reactions in vitro is to find an effective regeneration system for the necessary co-enzyme (mostly NAD(P)H) (Hollmann et al., 2001; Lee et al.,2011; Maenaka et al., 2012; Park et al., 2008; Ruppert et al., 1988; Zhu et al., 2006). The well established methods for the regeneration of the nicotinamide co-enzyme mainly consist of an enzyme-coupled approach utilizing formate dehydrogenase or glucose-6-phosphate dehydrogenase. Because the redox coenzyme couple NADH/NAD⁺ is ubiquitous and controls so much of our oxidation/reduction nature, there has been a long-standing interest in the mechanisms of the redox interconversions (Zhu et al., 2003). The high cost of these co-factors, however, is prohibitive of industrialization of many promising enzymatic processes. An efficient method of their in situ regeneration is the only means for making the processes economically and industrially feasible (Song et al., 2008). Therefore, many researchers have given considerable attention to the chemistry of NADH and its models (Hollmann et al., 2001). In this work, we have synthesized the title compound as a NAD⁺ model and report herein its crystal structure.

The molecular structure of the title compound is shown in Fig. 1. The benzene ring (C8-C13) and pyridine ring (N3/C2-C6) form a dihedral angle of 82.0 (1)°. In the crystal, intermolecular N—H···Br and N—H···O hydrogen bonds link the components to form chains along [001]. In addition, weak C—H···O and C—H···Br hydrogen bonds are observed.

Related literature top

The title compound was prepared as an NAD⁺ (nicotinamide adenine dinucleotide) model. For effective regeneration systems for co-enzymes (e.g. NADH), see: Hollmann et al. (2001); Lee et al. (2011); Maenaka et al. (2012); Park et al. (2008); Ruppert et al. (1988); Zhu et al. (2006). For the mechanisms of redox interconversions (NADH/NAD⁺), see: Zhu et al. (2003); Song et al. (2008).

Experimental top

Nicotinamide (123.4 mg, 1 mmol) was dissolved in 10 ml acetonitrile. After stirring for a few minutes, 2-nitrobenzyl bromide (220.4 mg, 1 mmol) was carefully added to the reaction mixture. The solution was stirred for 3 h at 353K. The precipitate was filtered, washed three times with methylene chloride, and dried under vacuum. Crystals suitable for X-ray analysis were obtained from a methanol soution of the title compound in a few days.

Computing details top

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

Fig. 1. The molecular structure with displacement ellipsoids shown at the 50% probability level.

3-Carbamoyl-1-(2-nitrobenzyl)pyridinium bromide top

Crystal data top

C₁₃H₁₂N₃O₃⁺·Br⁻	F(000) = 680
M_r = 338.17	D_x = 1.636 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 11909 reflections
a = 17.576 (4) Å	θ = 2.7–27.6°
b = 7.9990 (16) Å	µ = 3.01 mm⁻¹
c = 10.152 (2) Å	T = 293 K
β = 105.88 (3)°	Block, colorless
V = 1372.8 (5) Å³	0.15 × 0.15 × 0.10 mm
Z = 4

Data collection top

Bruker SMART CCD diffractometer	2684 independent reflections
Radiation source: fine-focus sealed tube	2081 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.034
ϕ and ω scans	θ_max = 26.0°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 1997)	h = −21→21
T_min = 0.661, T_max = 0.753	k = −9→9
7399 measured reflections	l = −10→12

Refinement top

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)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.086	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	w = 1/[σ²(F_o²) + (0.0287P)² + 0.3626P] where P = (F_o² + 2F_c²)/3
2684 reflections	(Δ/σ)_max = 0.001
187 parameters	Δρ_max = 0.36 e Å⁻³
2 restraints	Δρ_min = −0.38 e Å⁻³

Crystal data top

C₁₃H₁₂N₃O₃⁺·Br⁻	V = 1372.8 (5) Å³
M_r = 338.17	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 17.576 (4) Å	µ = 3.01 mm⁻¹
b = 7.9990 (16) Å	T = 293 K
c = 10.152 (2) Å	0.15 × 0.15 × 0.10 mm
β = 105.88 (3)°

Data collection top

Bruker SMART CCD diffractometer	2684 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 1997)	2081 reflections with I > 2σ(I)
T_min = 0.661, T_max = 0.753	R_int = 0.034
7399 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.036	2 restraints
wR(F²) = 0.086	H atoms treated by a mixture of independent and constrained refinement
S = 1.04	Δρ_max = 0.36 e Å⁻³
2684 reflections	Δρ_min = −0.38 e Å⁻³
187 parameters

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq
Br1	0.299001 (18)	0.53711 (4)	0.36253 (3)	0.04487 (13)
N1	0.51901 (17)	0.2174 (4)	0.9902 (3)	0.0556 (7)
H1A	0.5634 (10)	0.181 (4)	1.041 (3)	0.067*
H1B	0.506 (2)	0.193 (5)	0.9045 (10)	0.067*
N2	0.09788 (14)	0.6339 (3)	1.1536 (2)	0.0374 (6)
N3	0.27770 (14)	0.5158 (3)	0.9346 (2)	0.0333 (5)
O1	0.48818 (12)	0.3289 (3)	1.1724 (2)	0.0515 (6)
O2	0.11894 (12)	0.7569 (3)	1.1007 (2)	0.0468 (5)
O3	0.06762 (15)	0.6449 (3)	1.2487 (3)	0.0648 (7)
C1	0.47318 (17)	0.3051 (4)	1.0485 (3)	0.0396 (7)
C2	0.40031 (16)	0.3825 (3)	0.9549 (3)	0.0330 (6)
C3	0.38718 (18)	0.3982 (4)	0.8142 (3)	0.0411 (7)
H3	0.4249	0.3592	0.7728	0.049*
C4	0.31891 (19)	0.4710 (4)	0.7355 (3)	0.0444 (8)
H4	0.3101	0.4811	0.6412	0.053*
C5	0.26429 (18)	0.5282 (4)	0.7981 (3)	0.0397 (7)
H5	0.2175	0.5760	0.7459	0.048*
C6	0.34414 (16)	0.4456 (3)	1.0136 (3)	0.0329 (6)
H6	0.3523	0.4396	1.1080	0.040*
C7	0.21733 (16)	0.5811 (3)	0.9988 (3)	0.0340 (7)
H7A	0.1859	0.6657	0.9398	0.041*
H7B	0.2436	0.6335	1.0854	0.041*
C8	0.16318 (15)	0.4428 (3)	1.0230 (3)	0.0298 (6)
C9	0.16802 (17)	0.2812 (4)	0.9765 (3)	0.0372 (7)
H9	0.2030	0.2585	0.9246	0.045*
C10	0.12235 (18)	0.1532 (4)	1.0052 (3)	0.0443 (8)
H10	0.1267	0.0464	0.9717	0.053*
C11	0.07044 (18)	0.1813 (4)	1.0828 (3)	0.0429 (7)
H11	0.0404	0.0941	1.1028	0.051*
C12	0.06342 (17)	0.3402 (4)	1.1305 (3)	0.0394 (7)
H12	0.0284	0.3615	1.1825	0.047*
C13	0.10931 (15)	0.4683 (3)	1.1001 (3)	0.0307 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0467 (2)	0.0500 (2)	0.0367 (2)	−0.00517 (15)	0.00936 (14)	0.00137 (15)
N1	0.0406 (17)	0.066 (2)	0.0561 (19)	0.0114 (15)	0.0063 (15)	−0.0072 (16)
N2	0.0361 (14)	0.0353 (15)	0.0415 (15)	0.0064 (11)	0.0120 (11)	−0.0022 (12)
N3	0.0364 (14)	0.0322 (13)	0.0346 (13)	−0.0001 (10)	0.0152 (11)	0.0025 (10)
O1	0.0402 (12)	0.0710 (16)	0.0435 (14)	0.0001 (11)	0.0117 (10)	0.0118 (12)
O2	0.0491 (13)	0.0332 (12)	0.0613 (15)	−0.0007 (10)	0.0202 (11)	−0.0023 (11)
O3	0.0894 (19)	0.0559 (16)	0.0689 (16)	0.0129 (13)	0.0549 (15)	−0.0026 (13)
C1	0.0320 (16)	0.0412 (18)	0.047 (2)	−0.0050 (13)	0.0134 (14)	0.0044 (15)
C2	0.0314 (15)	0.0317 (16)	0.0369 (16)	−0.0060 (12)	0.0111 (12)	0.0002 (13)
C3	0.0445 (18)	0.0419 (17)	0.0431 (18)	−0.0009 (14)	0.0224 (15)	−0.0049 (15)
C4	0.053 (2)	0.0526 (19)	0.0301 (16)	0.0042 (16)	0.0158 (14)	0.0022 (15)
C5	0.0418 (17)	0.0398 (17)	0.0348 (17)	0.0044 (14)	0.0056 (14)	0.0070 (14)
C6	0.0343 (15)	0.0359 (17)	0.0289 (15)	−0.0028 (13)	0.0092 (12)	0.0045 (12)
C7	0.0352 (16)	0.0331 (16)	0.0373 (16)	0.0037 (12)	0.0160 (13)	0.0013 (12)
C8	0.0278 (14)	0.0323 (16)	0.0274 (14)	0.0010 (11)	0.0044 (11)	0.0011 (12)
C9	0.0395 (16)	0.0374 (17)	0.0363 (17)	0.0032 (13)	0.0131 (13)	−0.0050 (13)
C10	0.0530 (19)	0.0298 (17)	0.0490 (19)	−0.0039 (14)	0.0121 (15)	−0.0054 (14)
C11	0.0438 (18)	0.0368 (18)	0.0486 (19)	−0.0129 (14)	0.0134 (15)	0.0015 (15)
C12	0.0330 (16)	0.0449 (19)	0.0425 (18)	−0.0027 (13)	0.0141 (13)	0.0028 (14)
C13	0.0307 (14)	0.0283 (14)	0.0320 (15)	−0.0001 (12)	0.0067 (12)	−0.0019 (12)

Geometric parameters (Å, º) top

N1—C1	1.324 (4)	C4—H4	0.9300
N1—H1A	0.860 (2)	C5—H5	0.9300
N1—H1B	0.860 (2)	C6—H6	0.9300
N2—O2	1.226 (3)	C7—C8	1.523 (4)
N2—O3	1.227 (3)	C7—H7A	0.9700
N2—C13	1.466 (4)	C7—H7B	0.9700
N3—C5	1.344 (4)	C8—C9	1.387 (4)
N3—C6	1.345 (4)	C8—C13	1.398 (4)
N3—C7	1.484 (3)	C9—C10	1.381 (4)
O1—C1	1.227 (4)	C9—H9	0.9300
C1—C2	1.503 (4)	C10—C11	1.377 (4)
C2—C6	1.381 (4)	C10—H10	0.9300
C2—C3	1.389 (4)	C11—C12	1.377 (4)
C3—C4	1.376 (4)	C11—H11	0.9300
C3—H3	0.9300	C12—C13	1.390 (4)
C4—C5	1.367 (4)	C12—H12	0.9300

C1—N1—H1A	119 (2)	C2—C6—H6	120.0
C1—N1—H1B	124 (3)	N3—C7—C8	111.6 (2)
H1A—N1—H1B	118 (4)	N3—C7—H7A	109.3
O2—N2—O3	122.4 (3)	C8—C7—H7A	109.3
O2—N2—C13	118.3 (2)	N3—C7—H7B	109.3
O3—N2—C13	119.3 (3)	C8—C7—H7B	109.3
C5—N3—C6	121.6 (2)	H7A—C7—H7B	108.0
C5—N3—C7	118.8 (2)	C9—C8—C13	116.1 (2)
C6—N3—C7	119.6 (2)	C9—C8—C7	121.5 (2)
O1—C1—N1	123.7 (3)	C13—C8—C7	122.2 (2)
O1—C1—C2	119.4 (3)	C10—C9—C8	121.8 (3)
N1—C1—C2	116.9 (3)	C10—C9—H9	119.1
C6—C2—C3	118.3 (3)	C8—C9—H9	119.1
C6—C2—C1	117.6 (3)	C11—C10—C9	120.9 (3)
C3—C2—C1	124.1 (3)	C11—C10—H10	119.5
C4—C3—C2	120.6 (3)	C9—C10—H10	119.5
C4—C3—H3	119.7	C10—C11—C12	119.3 (3)
C2—C3—H3	119.7	C10—C11—H11	120.4
C5—C4—C3	118.9 (3)	C12—C11—H11	120.4
C5—C4—H4	120.6	C11—C12—C13	119.3 (3)
C3—C4—H4	120.6	C11—C12—H12	120.4
N3—C5—C4	120.5 (3)	C13—C12—H12	120.4
N3—C5—H5	119.8	C12—C13—C8	122.6 (3)
C4—C5—H5	119.8	C12—C13—N2	115.9 (2)
N3—C6—C2	120.1 (3)	C8—C13—N2	121.4 (2)
N3—C6—H6	120.0

O1—C1—C2—C6	−14.2 (4)	N3—C7—C8—C13	170.4 (2)
N1—C1—C2—C6	167.5 (3)	C13—C8—C9—C10	−0.2 (4)
O1—C1—C2—C3	164.0 (3)	C7—C8—C9—C10	176.1 (3)
N1—C1—C2—C3	−14.3 (4)	C8—C9—C10—C11	−0.6 (5)
C6—C2—C3—C4	−1.7 (4)	C9—C10—C11—C12	0.9 (5)
C1—C2—C3—C4	−179.9 (3)	C10—C11—C12—C13	−0.5 (5)
C2—C3—C4—C5	0.2 (5)	C11—C12—C13—C8	−0.3 (4)
C6—N3—C5—C4	−0.8 (4)	C11—C12—C13—N2	179.5 (3)
C7—N3—C5—C4	179.3 (3)	C9—C8—C13—C12	0.7 (4)
C3—C4—C5—N3	1.0 (5)	C7—C8—C13—C12	−175.6 (3)
C5—N3—C6—C2	−0.7 (4)	C9—C8—C13—N2	−179.2 (2)
C7—N3—C6—C2	179.2 (2)	C7—C8—C13—N2	4.6 (4)
C3—C2—C6—N3	1.9 (4)	O2—N2—C13—C12	−160.2 (3)
C1—C2—C6—N3	−179.8 (2)	O3—N2—C13—C12	19.6 (4)
C5—N3—C7—C8	97.2 (3)	O2—N2—C13—C8	19.7 (4)
C6—N3—C7—C8	−82.7 (3)	O3—N2—C13—C8	−160.5 (3)
N3—C7—C8—C9	−5.6 (4)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O1ⁱ	0.86 (1)	2.30 (1)	3.143 (4)	168 (4)
N1—H1A···Br1ⁱⁱ	0.86 (1)	2.61 (1)	3.454 (3)	166 (3)
C4—H4···Br1	0.93	2.82	3.743 (3)	173
C7—H7B···Br1ⁱⁱⁱ	0.97	2.82	3.595 (3)	137
C5—H5···O2^iv	0.93	2.36	3.271 (4)	167
C3—H3···O1ⁱ	0.93	2.27	3.150 (4)	157

Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x+1, y−1/2, −z+3/2; (iii) x, y, z+1; (iv) x, −y+3/2, z−1/2.

Experimental details

Crystal data
Chemical formula	C₁₃H₁₂N₃O₃⁺·Br⁻
M_r	338.17
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	293
a, b, c (Å)	17.576 (4), 7.9990 (16), 10.152 (2)
β (°)	105.88 (3)
V (Å³)	1372.8 (5)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	3.01
Crystal size (mm)	0.15 × 0.15 × 0.10

Data collection
Diffractometer	Bruker SMART CCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 1997)
T_min, T_max	0.661, 0.753
No. of measured, independent and observed [I > 2σ(I)] reflections	7399, 2684, 2081
R_int	0.034
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.036, 0.086, 1.04
No. of reflections	2684
No. of parameters	187
No. of restraints	2
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.36, −0.38

Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1B···O1ⁱ	0.860 (2)	2.296 (9)	3.143 (4)	168 (4)
N1—H1A···Br1ⁱⁱ	0.860 (2)	2.614 (9)	3.454 (3)	166 (3)
C4—H4···Br1	0.93	2.82	3.743 (3)	173.2
C7—H7B···Br1ⁱⁱⁱ	0.97	2.82	3.595 (3)	137.3
C5—H5···O2^iv	0.93	2.36	3.271 (4)	166.7
C3—H3···O1ⁱ	0.93	2.27	3.150 (4)	157.2

Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) −x+1, y−1/2, −z+3/2; (iii) x, y, z+1; (iv) x, −y+3/2, z−1/2.

Acknowledgements

Financial support from the Converging Research Center Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011 K000675 and 2011 K000660), and Seoul National University of Science & Technology is gratefully acknowledged.

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