2-[(2,3,6,7-Tetra­hydro-1H,5H-benzo[ij]quinolizin-9-yl)methyl­ene]propane­dinitrile

Liang, M.; Yennawar, H.; Maroncelli, M.

doi:10.1107/S1600536809023678

organic compounds

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ISSN: 2056-9890

Volume 65| Part 7| July 2009| Page o1687

doi:10.1107/S1600536809023678

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2-[(2,3,6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)methylene]propanedinitrile

Min Liang,^a Hemant Yennawar ^a and Mark Maroncelli ^a ^*

^aDepartment of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA
^*Correspondence e-mail: maroncelli@psu.edu

(Received 20 May 2009; accepted 19 June 2009; online 27 June 2009)

The π system of the title compound, known as julolidinemalononitrile, C₁₆H₁₅N₃, is nearly planar, with a 3.5 (1)° twist between the aromatic and dicyanovinyl groups. The bond lengths indicate significant zwitterionic character in the ground state.

Related literature

For background to julolidinemalononitrile, see: Haidekker & Theodorakis (2007 ); Hooker & Torkelson (1995 ); Loutfy & Arnold (1982 ); Marder et al. (1993 ); Mennucci et al. (2009 ); Paul & Samanta (2008 ); Swalina & Maroncelli (2009 ). For related benzylidene malononitrile structure data see Wang et al. (2001 ); Antipin et al. (2003 ); van Bolhuis & Kiers (1978 ).

Experimental

Crystal data

C₁₆H₁₅N₃
M_r = 249.31
Monoclinic, P 2₁ /n
a = 4.9587 (9) Å
b = 15.614 (3) Å
c = 16.699 (3) Å
β = 91.609 (3)°
V = 1292.4 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 110 K
0.28 × 0.15 × 0.14 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2003 ) T_min = 0.979, T_max = 0.989
7359 measured reflections
3158 independent reflections
2323 reflections with I > 2σ(I)
R_int = 0.045

Refinement

R[F² > 2σ(F²)] = 0.070
wR(F²) = 0.169
S = 1.06
3158 reflections
172 parameters
H-atom parameters not refined
Δρ_max = 0.47 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); 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/S1600536809023678/bt2965sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809023678/bt2965Isup2.hkl

checkCIF report

Comment top

Julolidinemalononitrile, or JDMN for short (Fig. 1), has been extensively study for two distinct purposes. As a classic "push-pull" molecule with large hyperpolarizability, it has been used as a model system for understanding nonlinear optical properties of molecules (Mennucci et al., 2009). In a completely different context, the environmental sensitivity of the emission yield of JDMN has also made it a popular probe for local fluidity in conventional solvents (Loutfy & Arnold, 1982), polymers (Hooker & Torkelson, 1995), ionic liquids (Paul & Samanta, 2008) and biological media (Haidekker & Theodorakis, 2007). In an effort to understand this environmental sensitivity, we have undertaken electronic structure calculations of JDMN and related molecules (Swalina & Maroncelli, 2009). To partially test the accuracy of these calculations we obtained crystal structure data on JDMN, which are reported here.

The crystal packing of JDMN consists of interleaved columns of slipped π-stacked molecules (Fig. 2). The molecular structure contains planar dicyanovinyl and aminobenzene portions, which are nearly coplanar with one another. The 3.0 (4)° torsion angle (C12—C11—C13—C14), as well as the wide C11—C13—C14 angle (131.6 (2)°; θ in Table 1), results from the unfavorable overlap between the hydrogen atom on C12 and N3 (2.724 (2) Å). The julolidine ring system of JDMN adopts a syn ("W") conformation in which the amino nitrogen atom is nearly sp² hybridized (average 〈 CNC = 119.6 (2)°).

It is useful to view the ground and first excited state of JDMN as consisting of mixtures of the neutral and zwitterionic forms depicted in Scheme 2. Table 1 lists some structural parameters of JDMN useful in this context, together with data for several related molecules (see table 1). Ar1 and Ar2 are the average aromatic bond lengths that form the single (1) and double (2) bonds in the zwitterionic state; Δ_Ar is the difference between these bond lengths. As shown by the data in Table 1, JDMN and the closely related dimethylamino compound (DMN, R = N(CH₃)₂) exhibit non-negligible quinoidal character (Wang et al., 2001), whereas the unsubstituted (R = H) and halogen-substituted analogues (Antipin et al., 2003), represented here by R = F, do not. (For reference Δ_Ar = 0.14 Å in p-benzoquinone (van Bolhuis & Kiers, 1978)). Table 1 also lists bond lengths in the vinyl portion of the molecule, as well as Δ_pm the bond-length alternation in the polymethine chain. Δ_pm is small in both JDMN and DMN compared to the ideal polymethine value of 0.11 Å.(Marder et al., 1993) In contrast, the values of Δ_pm in the H– and F-substituted analogues are much closer to the ideal. Both the difference in aromatic bond and vinyl bond lengths indicate substantial zwitterionic character in the ground state of the push-pull molecule JDMN (as well as in DMN).

Related literature top

For background to julolidinemalononitrile, see: Haidekker & Theodorakis (2007); Hooker & Torkelson (1995); Loutfy & Arnold (1982); Marder et al. (1993); Mennucci et al. (2009); Paul & Samanta (2008); Swalina & Maroncelli (2009). For related benzylidene malononitrile structure data see Wang et al. (2001); Antipin et al. (2003); van Bolhuis & Kiers (1978).

Experimental top

JDMN was dissolved in a 1:1 (v/v) mixture of CH₂Cl₂ and ethanol. Orange block-shaped crystals of JDMN were grown by evaporating solvents slowly at room temperature.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SMART (Bruker, 2003); data reduction: SAINT (Bruker, 2003); 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. : Molecular structure of the title compound with displacement ellipsoids at the 50 % probability level.
	Fig. 2. : Crystal packing of the title compound.
	Fig. 3. The formation of the title compound.
	Fig. 4. The molecular structure and the meaning of R relevant for Table 1.

2-[(2,3,6,7-Tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)methylene]propanedinitrile top

Crystal data top

C₁₆H₁₅N₃	F(000) = 528
M_r = 249.31	D_x = 1.281 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 4.9587 (9) Å	Cell parameters from 1409 reflections
b = 15.614 (3) Å	θ = 2.8–26.9°
c = 16.699 (3) Å	µ = 0.08 mm⁻¹
β = 91.609 (3)°	T = 110 K
V = 1292.4 (4) Å³	Block, orange
Z = 4	0.28 × 0.15 × 0.14 mm

Data collection top

Bruker SMAT CCD area-detector diffractometer	3158 independent reflections
Radiation source: fine-focus sealed tube	2323 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.045
ϕ and ω scans	θ_max = 28.3°, θ_min = 1.8°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −6→6
T_min = 0.979, T_max = 0.989	k = −17→20
7359 measured reflections	l = −13→22

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)] = 0.070	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.169	H-atom parameters not refined
S = 1.06	w = 1/[σ²(F_o²) + (0.0705P)² + 0.5857P] where P = (F_o² + 2F_c²)/3
3158 reflections	(Δ/σ)_max < 0.001
172 parameters	Δρ_max = 0.47 e Å⁻³
0 restraints	Δρ_min = −0.28 e Å⁻³

Crystal data top

C₁₆H₁₅N₃	V = 1292.4 (4) Å³
M_r = 249.31	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 4.9587 (9) Å	µ = 0.08 mm⁻¹
b = 15.614 (3) Å	T = 110 K
c = 16.699 (3) Å	0.28 × 0.15 × 0.14 mm
β = 91.609 (3)°

Data collection top

Bruker SMAT CCD area-detector diffractometer	3158 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2003)	2323 reflections with I > 2σ(I)
T_min = 0.979, T_max = 0.989	R_int = 0.045
7359 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.070	0 restraints
wR(F²) = 0.169	H-atom parameters not refined
S = 1.06	Δρ_max = 0.47 e Å⁻³
3158 reflections	Δρ_min = −0.28 e Å⁻³
172 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 F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > σ(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ 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
C1	0.2573 (4)	0.10806 (16)	0.50258 (14)	0.0280 (5)
H1A	0.0851	0.1375	0.4999	0.034*
H1B	0.2221	0.0469	0.5024	0.034*
C2	0.4171 (5)	0.13118 (15)	0.43008 (14)	0.0283 (5)
H2A	0.3123	0.1182	0.3817	0.034*
H2B	0.5817	0.0977	0.4297	0.034*
C3	0.4856 (4)	0.22589 (15)	0.43229 (13)	0.0254 (5)
H3A	0.6008	0.2398	0.3881	0.030*
H3B	0.3215	0.2594	0.4264	0.030*
C4	0.6279 (4)	0.24797 (14)	0.51057 (12)	0.0193 (5)
C5	0.5717 (4)	0.20016 (13)	0.58073 (13)	0.0188 (4)
C6	0.6987 (4)	0.22407 (14)	0.65502 (12)	0.0197 (5)
C7	0.6322 (5)	0.17692 (15)	0.73081 (14)	0.0278 (5)
H7A	0.4936	0.2080	0.7586	0.033*
H7B	0.7916	0.1744	0.7658	0.033*
C8	0.5344 (5)	0.08689 (16)	0.71287 (15)	0.0318 (6)
H8A	0.6833	0.0523	0.6947	0.038*
H8B	0.4673	0.0611	0.7612	0.038*
C9	0.3142 (4)	0.08886 (15)	0.64948 (14)	0.0266 (5)
H9A	0.2593	0.0307	0.6367	0.032*
H9B	0.1592	0.1188	0.6699	0.032*
C10	0.8160 (4)	0.31257 (14)	0.51565 (12)	0.0191 (4)
H10	0.8534	0.3430	0.4694	0.023*
C11	0.9550 (4)	0.33494 (14)	0.58745 (12)	0.0186 (4)
C12	0.8864 (4)	0.28912 (14)	0.65663 (12)	0.0200 (5)
H12	0.9710	0.3033	0.7052	0.024*
C13	1.1540 (4)	0.40053 (14)	0.58368 (12)	0.0204 (5)
H13	1.1667	0.4259	0.5335	0.024*
C14	1.3297 (4)	0.43292 (14)	0.64049 (12)	0.0194 (4)
C15	1.5117 (4)	0.50020 (14)	0.62010 (13)	0.0221 (5)
C16	1.3544 (4)	0.40483 (14)	0.72205 (13)	0.0198 (4)
N1	0.4020 (3)	0.13133 (12)	0.57683 (11)	0.0233 (4)
N2	1.6579 (4)	0.55454 (13)	0.60473 (11)	0.0301 (5)
N3	1.3789 (4)	0.38375 (13)	0.78791 (12)	0.0290 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0236 (11)	0.0236 (13)	0.0364 (13)	−0.0022 (9)	−0.0050 (9)	−0.0035 (10)
C2	0.0272 (11)	0.0275 (13)	0.0299 (12)	0.0010 (10)	−0.0054 (9)	−0.0076 (10)
C3	0.0272 (11)	0.0261 (13)	0.0226 (11)	0.0027 (9)	−0.0032 (9)	−0.0011 (9)
C4	0.0194 (10)	0.0182 (11)	0.0204 (10)	0.0055 (8)	0.0009 (8)	−0.0025 (8)
C5	0.0158 (9)	0.0156 (11)	0.0252 (11)	0.0029 (8)	0.0047 (8)	−0.0021 (8)
C6	0.0209 (10)	0.0160 (11)	0.0225 (11)	0.0036 (8)	0.0047 (8)	0.0005 (8)
C7	0.0338 (12)	0.0249 (13)	0.0251 (12)	−0.0042 (10)	0.0063 (9)	0.0022 (10)
C8	0.0331 (13)	0.0279 (14)	0.0347 (13)	−0.0044 (10)	0.0043 (10)	0.0080 (11)
C9	0.0240 (11)	0.0187 (12)	0.0375 (13)	−0.0016 (9)	0.0061 (9)	0.0017 (10)
C10	0.0209 (10)	0.0188 (11)	0.0177 (10)	0.0026 (8)	0.0025 (8)	0.0019 (8)
C11	0.0191 (10)	0.0160 (11)	0.0209 (10)	0.0029 (8)	0.0039 (8)	0.0001 (8)
C12	0.0229 (10)	0.0199 (12)	0.0174 (10)	0.0026 (8)	0.0014 (8)	−0.0007 (8)
C13	0.0228 (10)	0.0197 (12)	0.0189 (10)	0.0020 (8)	0.0043 (8)	0.0027 (9)
C14	0.0203 (10)	0.0161 (11)	0.0220 (10)	0.0009 (8)	0.0059 (8)	−0.0008 (9)
C15	0.0266 (11)	0.0212 (12)	0.0183 (10)	0.0009 (9)	0.0003 (8)	−0.0002 (9)
C16	0.0189 (10)	0.0184 (11)	0.0221 (11)	0.0001 (8)	0.0025 (8)	−0.0023 (9)
N1	0.0210 (9)	0.0204 (10)	0.0284 (10)	−0.0037 (7)	0.0001 (7)	0.0008 (8)
N2	0.0379 (11)	0.0271 (12)	0.0252 (10)	−0.0081 (9)	0.0004 (8)	0.0005 (9)
N3	0.0302 (10)	0.0312 (12)	0.0257 (11)	−0.0018 (8)	0.0009 (8)	−0.0005 (9)

Geometric parameters (Å, º) top

C1—N1	1.461 (3)	C7—H7B	0.9700
C1—C2	1.509 (3)	C8—C9	1.500 (3)
C1—H1A	0.9700	C8—H8A	0.9700
C1—H1B	0.9700	C8—H8B	0.9700
C2—C3	1.518 (3)	C9—N1	1.460 (3)
C2—H2A	0.9700	C9—H9A	0.9700
C2—H2B	0.9700	C9—H9B	0.9700
C3—C4	1.508 (3)	C10—C11	1.410 (3)
C3—H3A	0.9700	C10—H10	0.9300
C3—H3B	0.9700	C11—C12	1.409 (3)
C4—C10	1.375 (3)	C11—C13	1.425 (3)
C4—C5	1.423 (3)	C12—H12	0.9300
C5—N1	1.365 (3)	C13—C14	1.367 (3)
C5—C6	1.425 (3)	C13—H13	0.9300
C6—C12	1.377 (3)	C14—C15	1.432 (3)
C6—C7	1.509 (3)	C14—C16	1.433 (3)
C7—C8	1.514 (3)	C15—N2	1.150 (3)
C7—H7A	0.9700	C16—N3	1.151 (3)

N1—C1—C2	111.41 (18)	C9—C8—C7	110.1 (2)
N1—C1—H1A	109.3	C9—C8—H8A	109.6
C2—C1—H1A	109.3	C7—C8—H8A	109.6
N1—C1—H1B	109.3	C9—C8—H8B	109.6
C2—C1—H1B	109.3	C7—C8—H8B	109.6
H1A—C1—H1B	108.0	H8A—C8—H8B	108.2
C1—C2—C3	109.62 (19)	N1—C9—C8	111.58 (18)
C1—C2—H2A	109.7	N1—C9—H9A	109.3
C3—C2—H2A	109.7	C8—C9—H9A	109.3
C1—C2—H2B	109.7	N1—C9—H9B	109.3
C3—C2—H2B	109.7	C8—C9—H9B	109.3
H2A—C2—H2B	108.2	H9A—C9—H9B	108.0
C4—C3—C2	110.05 (18)	C4—C10—C11	123.28 (19)
C4—C3—H3A	109.7	C4—C10—H10	118.4
C2—C3—H3A	109.7	C11—C10—H10	118.4
C4—C3—H3B	109.7	C12—C11—C10	116.62 (19)
C2—C3—H3B	109.7	C12—C11—C13	125.78 (19)
H3A—C3—H3B	108.2	C10—C11—C13	117.59 (19)
C10—C4—C5	118.83 (19)	C6—C12—C11	122.5 (2)
C10—C4—C3	121.43 (19)	C6—C12—H12	118.8
C5—C4—C3	119.73 (19)	C11—C12—H12	118.8
N1—C5—C4	120.55 (19)	C14—C13—C11	131.6 (2)
N1—C5—C6	120.29 (19)	C14—C13—H13	114.2
C4—C5—C6	119.15 (19)	C11—C13—H13	114.2
C12—C6—C5	119.47 (19)	C13—C14—C15	120.00 (19)
C12—C6—C7	120.5 (2)	C13—C14—C16	125.6 (2)
C5—C6—C7	120.06 (19)	C15—C14—C16	114.40 (18)
C6—C7—C8	111.31 (19)	N2—C15—C14	179.1 (2)
C6—C7—H7A	109.4	N3—C16—C14	178.3 (2)
C8—C7—H7A	109.4	C5—N1—C9	121.04 (19)
C6—C7—H7B	109.4	C5—N1—C1	121.57 (19)
C8—C7—H7B	109.4	C9—N1—C1	116.21 (18)
H7A—C7—H7B	108.0

N1—C1—C2—C3	−56.0 (2)	C5—C6—C12—C11	1.4 (3)
C1—C2—C3—C4	54.6 (2)	C7—C6—C12—C11	180.00 (19)
C2—C3—C4—C10	149.2 (2)	C10—C11—C12—C6	1.6 (3)
C2—C3—C4—C5	−29.5 (3)	C13—C11—C12—C6	−177.4 (2)
C10—C4—C5—N1	−174.91 (18)	C12—C11—C13—C14	3.0 (4)
C3—C4—C5—N1	3.9 (3)	C10—C11—C13—C14	−176.0 (2)
C10—C4—C5—C6	4.0 (3)	C11—C13—C14—C15	−179.9 (2)
C3—C4—C5—C6	−177.27 (18)	C11—C13—C14—C16	0.7 (4)
N1—C5—C6—C12	174.60 (18)	C13—C14—C15—N2	154 (17)
C4—C5—C6—C12	−4.3 (3)	C16—C14—C15—N2	−26 (17)
N1—C5—C6—C7	−4.0 (3)	C13—C14—C16—N3	−179 (100)
C4—C5—C6—C7	177.16 (18)	C15—C14—C16—N3	2 (9)
C12—C6—C7—C8	−153.2 (2)	C4—C5—N1—C9	−171.71 (18)
C5—C6—C7—C8	25.4 (3)	C6—C5—N1—C9	9.4 (3)
C6—C7—C8—C9	−50.6 (3)	C4—C5—N1—C1	−4.6 (3)
C7—C8—C9—N1	56.3 (3)	C6—C5—N1—C1	176.57 (19)
C5—C4—C10—C11	−0.8 (3)	C8—C9—N1—C5	−36.2 (3)
C3—C4—C10—C11	−179.57 (19)	C8—C9—N1—C1	156.0 (2)
C4—C10—C11—C12	−2.0 (3)	C2—C1—N1—C5	31.3 (3)
C4—C10—C11—C13	177.13 (19)	C2—C1—N1—C9	−160.98 (19)

Experimental details

Crystal data
Chemical formula	C₁₆H₁₅N₃
M_r	249.31
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	110
a, b, c (Å)	4.9587 (9), 15.614 (3), 16.699 (3)
β (°)	91.609 (3)
V (Å³)	1292.4 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.08
Crystal size (mm)	0.28 × 0.15 × 0.14

Data collection
Diffractometer	Bruker SMAT CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2003)
T_min, T_max	0.979, 0.989
No. of measured, independent and observed [I > 2σ(I)] reflections	7359, 3158, 2323
R_int	0.045
(sin θ/λ)_max (Å⁻¹)	0.667

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.070, 0.169, 1.06
No. of reflections	3158
No. of parameters	172
H-atom treatment	H-atom parameters not refined
Δρ_max, Δρ_min (e Å⁻³)	0.47, −0.28

Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Table 1. Selected parameters (Å, °) and comparison to related molecules top

Molecule	R—C5	Ar1	Ar2	Δ_Ar	C11—C13	C13—C14	C—CN	Δ_pm	C≡N	θ	τ
JDMN^a	1.365	1.417	1.376	0.04	1.425	1.367	1.433	0.06	1.151	132	3
N(CH₃)₂^b	1.359	1.410	1.366	0.04	1.423	1.367	1.431	0.06	1.142	132	7
H^c		1.387	1.379	0.01	1.450	1.350	1.440	0.09	1.145	131	10
F^c	1.356	1.377	1.380	0.00	1.454	1.341	1.437	0.10	1.133	132	5

Notes: Ar1 = average {C10—C11, C11—C12, C4—C5, C5—C6}; Ar2 = average {C4—C10, C6—C12}; Δ = Ar1–Ar2 C—CN = average{C14—C15, C14—C16}; Δpm = average{C11—C13, C14—C15, C14—C16} - (C13—C14); θ = the C11—C13—C14 angle; τ = the C12—C11—C13—C14 torsion angle. Notes: (a) This work; (b) Wang et al. (2001); (c) Antipin et al. (2003).

Acknowledgements

This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Science, US Department of Energy at PSU by grant No. DE—FG02–89ER14020. We also acknowledge NSF funding (CHEM-0131112) for the X-ray equipment.

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