organic compounds
1,3-Dibenzyl-2-methylbenzimidazolium chloride
aInstitute of Nanomaterials and Nanotechnology, Avenue de l'Armée Royale, Madinat El Irfane, 10100 Rabat, Morocco, bCNRST Division of UATRS Angle Allal Fassi/FAR, BP 8027 Hay Riad, 10000 Rabat, Morocco, cLaboratoire de Chimie Organique Hétérocyclique, Pôle de Compétences Pharmacochimie, Université Mohammed V-Agdal, BP 1014 Avenue Ibn Batout, Rabat, Morocco, and dDepartment of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
*Correspondence e-mail: seikweng@um.edu.my
The cation of the title salt, C22H21N2+·Cl−, contains a planar benzimidazolium unit (r.m.s. deviation = 0.02 Å); the phenyl rings of the benzyl substituents form dihedral angles of 68.2 (1) and 79.7 (1)° with the plane of the benzimidazolium fragment.
Experimental
Crystal data
|
Data collection: APEX2 (Bruker, 2005); cell SAINT (Bruker, 2005); 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: publCIF (Westrip, 2010).
Supporting information
https://doi.org/10.1107/S1600536810002588/bt5179sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810002588/bt5179Isup2.hkl
To a solution of 2-methylbenzimidazole (1 g, 7.57 mmol) in DMF (20 ml) was added benzyl chloride (2,66 ml, 22.7 mmol), potassium carbonate (1.25 g, 9.08 mmol) and a catalytic amount of tetra-n-butylammonium bromide. The mixture was stirred for 24 h. The solution was filtered and the solvent removed under reduced pressure. The residue was recrystallized from ethanol to afford 1,3-dibenzyl-2-methyl-benzimidazolium chloride as colorless crystals.
H-atoms were placed in calculated positions (C—H 0.93–0.97 Å) and were included in the
in the riding model approximation, with U(H) set to 1.2–1.5U(C).Data collection: APEX2 (Bruker, 2005); cell
SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); 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: publCIF (Westrip, 2010).Fig. 1. Anisotropic displacement ellipsoid plot (Barbour, 2001) of the title compound at the 50% probability level; hydrogen atoms are drawn as spheres of an arbitrary radius. |
C22H21N2+·Cl− | Z = 2 |
Mr = 348.86 | F(000) = 368 |
Triclinic, P1 | Dx = 1.271 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 9.2539 (2) Å | Cell parameters from 8258 reflections |
b = 9.4677 (2) Å | θ = 2.5–29.1° |
c = 12.0984 (3) Å | µ = 0.22 mm−1 |
α = 72.139 (1)° | T = 293 K |
β = 81.376 (1)° | Block, colorless |
γ = 64.605 (1)° | 0.30 × 0.30 × 0.30 mm |
V = 911.20 (4) Å3 |
Bruker APEXII diffractometer | 4175 independent reflections |
Radiation source: fine-focus sealed tube | 3336 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.028 |
φ and ω scans | θmax = 27.5°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −12→12 |
Tmin = 0.938, Tmax = 0.938 | k = −12→12 |
24459 measured reflections | l = −15→15 |
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)] = 0.038 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.124 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0687P)2 + 0.1373P] where P = (Fo2 + 2Fc2)/3 |
4175 reflections | (Δ/σ)max = 0.001 |
227 parameters | Δρmax = 0.23 e Å−3 |
0 restraints | Δρmin = −0.23 e Å−3 |
C22H21N2+·Cl− | γ = 64.605 (1)° |
Mr = 348.86 | V = 911.20 (4) Å3 |
Triclinic, P1 | Z = 2 |
a = 9.2539 (2) Å | Mo Kα radiation |
b = 9.4677 (2) Å | µ = 0.22 mm−1 |
c = 12.0984 (3) Å | T = 293 K |
α = 72.139 (1)° | 0.30 × 0.30 × 0.30 mm |
β = 81.376 (1)° |
Bruker APEXII diffractometer | 4175 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3336 reflections with I > 2σ(I) |
Tmin = 0.938, Tmax = 0.938 | Rint = 0.028 |
24459 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.124 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.23 e Å−3 |
4175 reflections | Δρmin = −0.23 e Å−3 |
227 parameters |
x | y | z | Uiso*/Ueq | ||
Cl1 | 0.29429 (4) | 0.33126 (4) | 0.00802 (3) | 0.04507 (14) | |
N1 | 0.77776 (14) | 0.02156 (14) | 0.14627 (10) | 0.0356 (3) | |
N2 | 0.91155 (14) | 0.15323 (14) | 0.16783 (10) | 0.0352 (3) | |
C1 | 0.61460 (19) | 0.30695 (19) | 0.16123 (16) | 0.0498 (4) | |
H1A | 0.5794 | 0.3046 | 0.2403 | 0.075* | |
H1B | 0.5340 | 0.3064 | 0.1200 | 0.075* | |
H1C | 0.6328 | 0.4036 | 0.1249 | 0.075* | |
C2 | 0.76494 (17) | 0.16248 (17) | 0.15880 (12) | 0.0360 (3) | |
C3 | 0.93932 (17) | −0.08252 (17) | 0.14577 (12) | 0.0349 (3) | |
C4 | 1.0170 (2) | −0.23710 (18) | 0.12901 (14) | 0.0434 (4) | |
H4 | 0.9608 | −0.2928 | 0.1179 | 0.052* | |
C5 | 1.1821 (2) | −0.3032 (2) | 0.12974 (15) | 0.0515 (4) | |
H5 | 1.2387 | −0.4067 | 0.1194 | 0.062* | |
C6 | 1.2669 (2) | −0.2194 (2) | 0.14549 (16) | 0.0541 (4) | |
H6 | 1.3781 | −0.2688 | 0.1458 | 0.065* | |
C7 | 1.18996 (19) | −0.0654 (2) | 0.16059 (14) | 0.0454 (4) | |
H7 | 1.2462 | −0.0092 | 0.1704 | 0.054* | |
C8 | 1.02401 (17) | 0.00110 (17) | 0.16028 (12) | 0.0350 (3) | |
C9 | 0.64487 (18) | −0.02047 (18) | 0.13464 (14) | 0.0416 (3) | |
H9 | 0.6788 | −0.0902 | 0.0830 | 0.050* | |
H9B | 0.5545 | 0.0780 | 0.1000 | 0.050* | |
C10 | 0.59317 (18) | −0.10561 (18) | 0.25015 (14) | 0.0411 (3) | |
C11 | 0.4779 (2) | −0.0170 (2) | 0.3180 (2) | 0.0646 (5) | |
H11 | 0.4329 | 0.0959 | 0.2926 | 0.078* | |
C12 | 0.4288 (3) | −0.0946 (3) | 0.4233 (2) | 0.0821 (7) | |
H12 | 0.3506 | −0.0341 | 0.4682 | 0.099* | |
C13 | 0.4951 (3) | −0.2606 (3) | 0.4616 (2) | 0.0750 (6) | |
H13 | 0.4628 | −0.3126 | 0.5329 | 0.090* | |
C14 | 0.6089 (3) | −0.3505 (3) | 0.3951 (2) | 0.0668 (5) | |
H14 | 0.6539 | −0.4633 | 0.4212 | 0.080* | |
C15 | 0.6566 (2) | −0.2729 (2) | 0.28935 (17) | 0.0526 (4) | |
H15 | 0.7325 | −0.3343 | 0.2438 | 0.063* | |
C16 | 0.95196 (19) | 0.28401 (18) | 0.17480 (13) | 0.0405 (3) | |
H16 | 0.8649 | 0.3876 | 0.1434 | 0.049* | |
H16B | 1.0466 | 0.2809 | 0.1268 | 0.049* | |
C17 | 0.98260 (18) | 0.27339 (17) | 0.29640 (13) | 0.0380 (3) | |
C18 | 0.9089 (2) | 0.2087 (2) | 0.39402 (15) | 0.0533 (4) | |
H18 | 0.8402 | 0.1638 | 0.3866 | 0.064* | |
C19 | 0.9367 (3) | 0.2104 (3) | 0.50305 (17) | 0.0700 (6) | |
H19 | 0.8861 | 0.1670 | 0.5682 | 0.084* | |
C20 | 1.0372 (3) | 0.2749 (3) | 0.5152 (2) | 0.0813 (7) | |
H20 | 1.0558 | 0.2754 | 0.5885 | 0.098* | |
C21 | 1.1109 (3) | 0.3392 (3) | 0.4191 (2) | 0.0821 (7) | |
H21 | 1.1794 | 0.3838 | 0.4274 | 0.099* | |
C22 | 1.0846 (2) | 0.3384 (2) | 0.31030 (18) | 0.0574 (5) | |
H22 | 1.1359 | 0.3820 | 0.2457 | 0.069* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cl1 | 0.0415 (2) | 0.0398 (2) | 0.0544 (2) | −0.01604 (16) | −0.00553 (16) | −0.01205 (16) |
N1 | 0.0346 (6) | 0.0361 (6) | 0.0407 (6) | −0.0176 (5) | −0.0027 (5) | −0.0109 (5) |
N2 | 0.0371 (6) | 0.0385 (6) | 0.0354 (6) | −0.0199 (5) | −0.0011 (5) | −0.0107 (5) |
C1 | 0.0415 (9) | 0.0420 (8) | 0.0686 (11) | −0.0158 (7) | −0.0026 (8) | −0.0196 (8) |
C2 | 0.0385 (7) | 0.0371 (7) | 0.0366 (7) | −0.0191 (6) | −0.0017 (6) | −0.0098 (6) |
C3 | 0.0364 (7) | 0.0378 (7) | 0.0309 (7) | −0.0168 (6) | −0.0005 (5) | −0.0076 (5) |
C4 | 0.0486 (9) | 0.0399 (8) | 0.0437 (8) | −0.0196 (7) | 0.0023 (7) | −0.0133 (6) |
C5 | 0.0488 (9) | 0.0421 (8) | 0.0559 (10) | −0.0122 (7) | 0.0056 (8) | −0.0155 (7) |
C6 | 0.0362 (8) | 0.0562 (10) | 0.0601 (10) | −0.0120 (7) | 0.0031 (7) | −0.0147 (8) |
C7 | 0.0374 (8) | 0.0555 (9) | 0.0460 (9) | −0.0224 (7) | −0.0002 (6) | −0.0125 (7) |
C8 | 0.0372 (7) | 0.0397 (7) | 0.0303 (7) | −0.0181 (6) | −0.0002 (5) | −0.0093 (5) |
C9 | 0.0385 (8) | 0.0411 (7) | 0.0527 (9) | −0.0201 (6) | −0.0082 (7) | −0.0139 (7) |
C10 | 0.0343 (7) | 0.0437 (8) | 0.0543 (9) | −0.0211 (6) | −0.0024 (6) | −0.0171 (7) |
C11 | 0.0597 (11) | 0.0542 (10) | 0.0887 (15) | −0.0312 (9) | 0.0230 (10) | −0.0311 (10) |
C12 | 0.0870 (16) | 0.0893 (16) | 0.0946 (17) | −0.0553 (14) | 0.0443 (14) | −0.0511 (14) |
C13 | 0.0851 (16) | 0.0911 (16) | 0.0633 (13) | −0.0583 (14) | 0.0143 (11) | −0.0146 (11) |
C14 | 0.0671 (12) | 0.0537 (10) | 0.0756 (13) | −0.0304 (10) | −0.0002 (10) | −0.0043 (10) |
C15 | 0.0498 (10) | 0.0451 (9) | 0.0647 (11) | −0.0213 (8) | 0.0049 (8) | −0.0171 (8) |
C16 | 0.0460 (8) | 0.0400 (7) | 0.0427 (8) | −0.0255 (7) | −0.0023 (6) | −0.0084 (6) |
C17 | 0.0377 (7) | 0.0307 (6) | 0.0463 (8) | −0.0109 (6) | −0.0046 (6) | −0.0141 (6) |
C18 | 0.0619 (11) | 0.0563 (10) | 0.0450 (9) | −0.0277 (9) | −0.0002 (8) | −0.0134 (8) |
C19 | 0.0869 (15) | 0.0691 (13) | 0.0454 (10) | −0.0223 (11) | −0.0005 (10) | −0.0183 (9) |
C20 | 0.1008 (18) | 0.0796 (15) | 0.0648 (14) | −0.0186 (13) | −0.0261 (13) | −0.0366 (12) |
C21 | 0.0938 (17) | 0.0875 (16) | 0.0920 (17) | −0.0434 (14) | −0.0242 (14) | −0.0406 (14) |
C22 | 0.0606 (11) | 0.0575 (10) | 0.0691 (12) | −0.0315 (9) | −0.0070 (9) | −0.0236 (9) |
N1—C2 | 1.3416 (18) | C10—C11 | 1.382 (2) |
N1—C3 | 1.3941 (18) | C11—C12 | 1.381 (3) |
N1—C9 | 1.4821 (18) | C11—H11 | 0.9300 |
N2—C2 | 1.3406 (18) | C12—C13 | 1.368 (3) |
N2—C8 | 1.3902 (18) | C12—H12 | 0.9300 |
N2—C16 | 1.4664 (18) | C13—C14 | 1.370 (3) |
C1—C2 | 1.479 (2) | C13—H13 | 0.9300 |
C1—H1A | 0.9600 | C14—C15 | 1.380 (3) |
C1—H1B | 0.9600 | C14—H14 | 0.9300 |
C1—H1C | 0.9600 | C15—H15 | 0.9300 |
C3—C8 | 1.389 (2) | C16—C17 | 1.505 (2) |
C3—C4 | 1.391 (2) | C16—H16 | 0.9700 |
C4—C5 | 1.381 (2) | C16—H16B | 0.9700 |
C4—H4 | 0.9300 | C17—C22 | 1.381 (2) |
C5—C6 | 1.397 (3) | C17—C18 | 1.381 (2) |
C5—H5 | 0.9300 | C18—C19 | 1.387 (3) |
C6—C7 | 1.378 (2) | C18—H18 | 0.9300 |
C6—H6 | 0.9300 | C19—C20 | 1.358 (4) |
C7—C8 | 1.388 (2) | C19—H19 | 0.9300 |
C7—H7 | 0.9300 | C20—C21 | 1.368 (4) |
C9—C10 | 1.507 (2) | C20—H20 | 0.9300 |
C9—H9 | 0.9700 | C21—C22 | 1.377 (3) |
C9—H9B | 0.9700 | C21—H21 | 0.9300 |
C10—C15 | 1.380 (2) | C22—H22 | 0.9300 |
C2—N1—C3 | 108.77 (12) | C11—C10—C9 | 120.38 (15) |
C2—N1—C9 | 126.81 (12) | C10—C11—C12 | 120.55 (19) |
C3—N1—C9 | 124.43 (12) | C10—C11—H11 | 119.7 |
C2—N2—C8 | 108.89 (12) | C12—C11—H11 | 119.7 |
C2—N2—C16 | 126.78 (13) | C13—C12—C11 | 120.0 (2) |
C8—N2—C16 | 124.15 (12) | C13—C12—H12 | 120.0 |
C2—C1—H1A | 109.5 | C11—C12—H12 | 120.0 |
C2—C1—H1B | 109.5 | C14—C13—C12 | 120.2 (2) |
H1A—C1—H1B | 109.5 | C14—C13—H13 | 119.9 |
C2—C1—H1C | 109.5 | C12—C13—H13 | 119.9 |
H1A—C1—H1C | 109.5 | C13—C14—C15 | 119.71 (19) |
H1B—C1—H1C | 109.5 | C13—C14—H14 | 120.1 |
N2—C2—N1 | 109.12 (13) | C15—C14—H14 | 120.1 |
N2—C2—C1 | 124.66 (13) | C10—C15—C14 | 120.95 (18) |
N1—C2—C1 | 126.21 (13) | C10—C15—H15 | 119.5 |
C8—C3—C4 | 121.57 (14) | C14—C15—H15 | 119.5 |
C8—C3—N1 | 106.52 (12) | N2—C16—C17 | 113.56 (12) |
C4—C3—N1 | 131.83 (14) | N2—C16—H16 | 108.9 |
C5—C4—C3 | 116.23 (15) | C17—C16—H16 | 108.9 |
C5—C4—H4 | 121.9 | N2—C16—H16B | 108.9 |
C3—C4—H4 | 121.9 | C17—C16—H16B | 108.9 |
C4—C5—C6 | 122.05 (16) | H16—C16—H16B | 107.7 |
C4—C5—H5 | 119.0 | C22—C17—C18 | 118.45 (16) |
C6—C5—H5 | 119.0 | C22—C17—C16 | 117.98 (14) |
C7—C6—C5 | 121.71 (16) | C18—C17—C16 | 123.51 (14) |
C7—C6—H6 | 119.1 | C17—C18—C19 | 120.39 (18) |
C5—C6—H6 | 119.1 | C17—C18—H18 | 119.8 |
C6—C7—C8 | 116.38 (15) | C19—C18—H18 | 119.8 |
C6—C7—H7 | 121.8 | C20—C19—C18 | 120.4 (2) |
C8—C7—H7 | 121.8 | C20—C19—H19 | 119.8 |
C7—C8—C3 | 122.05 (14) | C18—C19—H19 | 119.8 |
C7—C8—N2 | 131.20 (14) | C19—C20—C21 | 119.68 (19) |
C3—C8—N2 | 106.69 (12) | C19—C20—H20 | 120.2 |
N1—C9—C10 | 111.98 (12) | C21—C20—H20 | 120.2 |
N1—C9—H9 | 109.2 | C20—C21—C22 | 120.6 (2) |
C10—C9—H9 | 109.2 | C20—C21—H21 | 119.7 |
N1—C9—H9B | 109.2 | C22—C21—H21 | 119.7 |
C10—C9—H9B | 109.2 | C21—C22—C17 | 120.4 (2) |
H9—C9—H9B | 107.9 | C21—C22—H22 | 119.8 |
C15—C10—C11 | 118.51 (16) | C17—C22—H22 | 119.8 |
C15—C10—C9 | 121.09 (15) | ||
C8—N2—C2—N1 | 0.33 (16) | C16—N2—C8—C3 | −175.22 (12) |
C16—N2—C2—N1 | 175.59 (12) | C2—N1—C9—C10 | −93.34 (17) |
C8—N2—C2—C1 | −179.08 (14) | C3—N1—C9—C10 | 86.67 (17) |
C16—N2—C2—C1 | −3.8 (2) | N1—C9—C10—C15 | −93.28 (17) |
C3—N1—C2—N2 | −0.73 (16) | N1—C9—C10—C11 | 88.23 (18) |
C9—N1—C2—N2 | 179.28 (13) | C15—C10—C11—C12 | 0.7 (3) |
C3—N1—C2—C1 | 178.67 (14) | C9—C10—C11—C12 | 179.22 (19) |
C9—N1—C2—C1 | −1.3 (2) | C10—C11—C12—C13 | 0.4 (4) |
C2—N1—C3—C8 | 0.84 (15) | C11—C12—C13—C14 | −0.8 (4) |
C9—N1—C3—C8 | −179.17 (12) | C12—C13—C14—C15 | 0.0 (4) |
C2—N1—C3—C4 | −175.93 (15) | C11—C10—C15—C14 | −1.5 (3) |
C9—N1—C3—C4 | 4.1 (2) | C9—C10—C15—C14 | −179.97 (16) |
C8—C3—C4—C5 | 1.1 (2) | C13—C14—C15—C10 | 1.1 (3) |
N1—C3—C4—C5 | 177.47 (15) | C2—N2—C16—C17 | 100.24 (17) |
C3—C4—C5—C6 | −0.5 (2) | C8—N2—C16—C17 | −85.18 (17) |
C4—C5—C6—C7 | −0.3 (3) | N2—C16—C17—C22 | 152.21 (15) |
C5—C6—C7—C8 | 0.5 (3) | N2—C16—C17—C18 | −30.7 (2) |
C6—C7—C8—C3 | 0.1 (2) | C22—C17—C18—C19 | 0.4 (3) |
C6—C7—C8—N2 | −176.73 (15) | C16—C17—C18—C19 | −176.69 (16) |
C4—C3—C8—C7 | −1.0 (2) | C17—C18—C19—C20 | −0.3 (3) |
N1—C3—C8—C7 | −178.13 (13) | C18—C19—C20—C21 | 0.3 (4) |
C4—C3—C8—N2 | 176.55 (13) | C19—C20—C21—C22 | −0.3 (4) |
N1—C3—C8—N2 | −0.62 (14) | C20—C21—C22—C17 | 0.3 (3) |
C2—N2—C8—C7 | 177.39 (15) | C18—C17—C22—C21 | −0.4 (3) |
C16—N2—C8—C7 | 2.0 (2) | C16—C17—C22—C21 | 176.83 (18) |
C2—N2—C8—C3 | 0.20 (15) |
Experimental details
Crystal data | |
Chemical formula | C22H21N2+·Cl− |
Mr | 348.86 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 9.2539 (2), 9.4677 (2), 12.0984 (3) |
α, β, γ (°) | 72.139 (1), 81.376 (1), 64.605 (1) |
V (Å3) | 911.20 (4) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.22 |
Crystal size (mm) | 0.30 × 0.30 × 0.30 |
Data collection | |
Diffractometer | Bruker APEXII diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.938, 0.938 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 24459, 4175, 3336 |
Rint | 0.028 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.124, 1.08 |
No. of reflections | 4175 |
No. of parameters | 227 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.23, −0.23 |
Computer programs: APEX2 (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001), publCIF (Westrip, 2010).
Acknowledgements
We thank Université Mohammed V-Agdal and the University of Malaya for supporting this study.
References
Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191. CrossRef CAS Google Scholar
Bruker (2005). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Jian, F.-F., Wang, H.-X., Xiao, H.-L. & Liu, G.-Y. (2003). Chin. J. Struct. Chem. 22, 669–672. CAS Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Westrip, S. P. (2010). publCIF. In preparation. Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.