supplementary materials

2,2'-(Diselane-1,2-diyl)dinicotinamide N,N'-dimethylformamide disolvate
The asymmetric unit of the title compound, C12H10N4O2Se2·2C3H7NO, contains two solvent molecules and two half molecules of the dinicotinamide, each of which sits on a center of symmetry passing through the middle of the Se-Se bond. In each molecule, the two pyridyl groups and diseleno group are approximately coplanar (r.m.s. deviations from planarity for all non-H atoms = 0.011 and 0.008 Å in the two molecules). Intermolecular N-H
O hydrogen bonds stablilize the crystal packing.
To a vigorously stirred solution of selenium powder (1.19 g, 15 mmol) and
absolute ethanol (30 ml), sodium borohydride (0.40 g, 10.6 mmol) was added at
0 °C. The mixture was warmed to room temperature and stirred for 2 h.
2-Chloro-nicotinamide (1.56 g, 10 mmol) was added and stirred for 7 days. O2
was passed through the solution slowly for 2 h after the reaction mixture was
acidfied by glacial acetic. The solvents were removed in vacuo and the residue
was extracted with hot dimethyl sulphoxide (DMSO) and filtered. The filtrate
was poured into water( 200 ml, cooled to 0 °C). The precipitate was separated
by filtration and recrystallized from DMSO-CH3OH(1:2) to give the product as
yellow crystals, yield: 1.56 g, 78%; m.p. 124-125 °C. 1H-NMR ( 300 MHz,
DCCl3) δ (ppm): 7.27 (d, 2H), 7.81 (s, 2H), 8.14 (d, 2H), 8.32 (s, 2H),
8.48 (s, 2H), 8.65 (s, 2H);77Se-NMR (57 MHz, DMSO-d6 ) δ(ppm): 524.77.
(type here to add refinement details)
Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
2,2'-(Diselane-1,2-diyl)dinicotinamide
N,
N'-dimethylformamide
disolvate
top
Crystal data top
| C12H10N4O2Se2·2C3H7NO | Z = 2 |
| Mr = 546.34 | F(000) = 548 |
| Triclinic, P1 | Dx = 1.593 Mg m−3 |
| a = 7.6101 (17) Å | Mo Kα radiation, λ = 0.71073 Å |
| b = 12.318 (3) Å | Cell parameters from 2815 reflections |
| c = 13.420 (3) Å | θ = 3.1–27.5° |
| α = 114.175 (2)° | µ = 3.28 mm−1 |
| β = 91.017 (3)° | T = 298 K |
| γ = 95.833 (3)° | Block, yellow |
| V = 1139.3 (4) Å3 | 0.30 × 0.20 × 0.20 mm |
Data collection top
Siemens SMART CCD diffractometer | 3937 independent reflections |
| Radiation source: fine-focus sealed tube | 3359 reflections with I > 2σ(I) |
| graphite | Rint = 0.0000 |
| phi and ω scans | θmax = 25.0°, θmin = 1.7° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→8 |
| Tmin = 0.439, Tmax = 0.560 | k = −14→13 |
| 3937 measured reflections | l = 0→15 |
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) = 0.097 | H-atom parameters constrained |
| S = 1.03 | w = 1/[σ2(Fo2) + (0.0416P)2 + 0.7097P] where P = (Fo2 + 2Fc2)/3 |
| 3937 reflections | (Δ/σ)max = 0.001 |
| 275 parameters | Δρmax = 0.38 e Å−3 |
| 0 restraints | Δρmin = −0.73 e Å−3 |
Crystal data top
| C12H10N4O2Se2·2C3H7NO | γ = 95.833 (3)° |
| Mr = 546.34 | V = 1139.3 (4) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 7.6101 (17) Å | Mo Kα radiation |
| b = 12.318 (3) Å | µ = 3.28 mm−1 |
| c = 13.420 (3) Å | T = 298 K |
| α = 114.175 (2)° | 0.30 × 0.20 × 0.20 mm |
| β = 91.017 (3)° | |
Data collection top
Siemens SMART CCD diffractometer | 3937 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3359 reflections with I > 2σ(I) |
| Tmin = 0.439, Tmax = 0.560 | Rint = 0.0000 |
| 3937 measured reflections | θmax = 25.0° |
Refinement top
| R[F2 > 2σ(F2)] = 0.036 | H-atom parameters constrained |
| wR(F2) = 0.097 | Δρmax = 0.38 e Å−3 |
| S = 1.03 | Δρmin = −0.73 e Å−3 |
| 3937 reflections | Absolute structure: ? |
| 275 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
Special details top
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. |
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 | Uiso*/Ueq | |
| Se1 | 0.44747 (5) | 0.90079 (3) | 0.43528 (3) | 0.04343 (13) | |
| Se2 | −0.00660 (5) | 0.90803 (3) | 0.92023 (2) | 0.04228 (13) | |
| N1 | 0.1532 (5) | 0.5410 (3) | 0.7795 (2) | 0.0635 (10) | |
| H1A | 0.1427 | 0.5036 | 0.7093 | 0.076* | |
| H1B | 0.2126 | 0.5139 | 0.8176 | 0.076* | |
| N2 | 0.0893 (4) | 0.8848 (2) | 1.1107 (2) | 0.0425 (7) | |
| N3 | 0.2600 (5) | 0.5278 (3) | 0.3920 (3) | 0.0592 (9) | |
| H3A | 0.2117 | 0.4794 | 0.3289 | 0.071* | |
| H3B | 0.2580 | 0.5066 | 0.4457 | 0.071* | |
| N4 | 0.5588 (4) | 0.9107 (3) | 0.6373 (2) | 0.0486 (7) | |
| N5 | 0.3752 (5) | 0.2618 (4) | 0.9343 (3) | 0.0708 (10) | |
| N6 | 0.0494 (5) | 0.2208 (3) | 0.4807 (2) | 0.0551 (8) | |
| O1 | −0.0074 (4) | 0.6808 (2) | 0.77632 (19) | 0.0673 (9) | |
| O2 | 0.3436 (5) | 0.6689 (2) | 0.3326 (2) | 0.0745 (9) | |
| O3 | 0.3116 (6) | 0.4039 (4) | 0.8778 (3) | 0.1119 (15) | |
| O4 | 0.1655 (4) | 0.4149 (2) | 0.5403 (2) | 0.0636 (8) | |
| C1 | 0.0787 (5) | 0.6393 (3) | 0.8283 (3) | 0.0453 (8) | |
| C2 | 0.0992 (4) | 0.7021 (3) | 0.9497 (2) | 0.0385 (7) | |
| C3 | 0.1484 (5) | 0.6470 (3) | 1.0157 (3) | 0.0444 (8) | |
| H3 | 0.1689 | 0.5671 | 0.9840 | 0.053* | |
| C4 | 0.1672 (5) | 0.7094 (3) | 1.1279 (3) | 0.0501 (9) | |
| H4 | 0.1983 | 0.6727 | 1.1728 | 0.060* | |
| C5 | 0.1388 (5) | 0.8271 (3) | 1.1708 (3) | 0.0481 (9) | |
| H5 | 0.1547 | 0.8700 | 1.2463 | 0.058* | |
| C6 | 0.0676 (4) | 0.8226 (3) | 1.0022 (2) | 0.0359 (7) | |
| C7 | 0.3379 (5) | 0.6354 (3) | 0.4068 (3) | 0.0485 (9) | |
| C8 | 0.4199 (5) | 0.7156 (3) | 0.5172 (3) | 0.0415 (8) | |
| C9 | 0.4458 (6) | 0.6768 (3) | 0.5990 (3) | 0.0555 (10) | |
| H9 | 0.4074 | 0.5980 | 0.5869 | 0.067* | |
| C10 | 0.5283 (6) | 0.7548 (4) | 0.6982 (3) | 0.0649 (12) | |
| H10 | 0.5460 | 0.7299 | 0.7539 | 0.078* | |
| C11 | 0.5836 (6) | 0.8695 (4) | 0.7131 (3) | 0.0597 (11) | |
| H11 | 0.6417 | 0.9216 | 0.7797 | 0.072* | |
| C12 | 0.4806 (4) | 0.8354 (3) | 0.5408 (3) | 0.0382 (7) | |
| C13 | 0.4094 (8) | 0.1434 (5) | 0.9066 (7) | 0.132 (3) | |
| H13A | 0.3984 | 0.0998 | 0.8285 | 0.198* | |
| H13B | 0.3259 | 0.1059 | 0.9390 | 0.198* | |
| H13C | 0.5273 | 0.1436 | 0.9334 | 0.198* | |
| C14 | 0.3803 (8) | 0.3421 (6) | 1.0492 (5) | 0.1017 (18) | |
| H14A | 0.3586 | 0.4203 | 1.0564 | 0.153* | |
| H14B | 0.4947 | 0.3471 | 1.0833 | 0.153* | |
| H14C | 0.2910 | 0.3120 | 1.0842 | 0.153* | |
| C15 | 0.3437 (7) | 0.3039 (5) | 0.8611 (4) | 0.0867 (15) | |
| H15 | 0.3463 | 0.2508 | 0.7882 | 0.104* | |
| C16 | −0.0269 (7) | 0.1122 (4) | 0.3893 (4) | 0.0864 (16) | |
| H16A | −0.0493 | 0.1295 | 0.3270 | 0.130* | |
| H16B | −0.1361 | 0.0820 | 0.4089 | 0.130* | |
| H16C | 0.0541 | 0.0530 | 0.3715 | 0.130* | |
| C17 | 0.0853 (7) | 0.2161 (4) | 0.5860 (4) | 0.0791 (14) | |
| H17A | 0.1766 | 0.2791 | 0.6280 | 0.119* | |
| H17B | 0.1233 | 0.1400 | 0.5741 | 0.119* | |
| H17C | −0.0205 | 0.2260 | 0.6252 | 0.119* | |
| C18 | 0.0939 (6) | 0.3203 (4) | 0.4690 (3) | 0.0571 (10) | |
| H18 | 0.0690 | 0.3193 | 0.4005 | 0.069* | |
Atomic displacement parameters (Å2) top| | U11 | U22 | U33 | U12 | U13 | U23 |
| Se1 | 0.0546 (2) | 0.0391 (2) | 0.0405 (2) | −0.00010 (15) | −0.00515 (15) | 0.02201 (17) |
| Se2 | 0.0608 (2) | 0.0352 (2) | 0.02975 (19) | 0.00734 (15) | −0.00560 (15) | 0.01226 (15) |
| N1 | 0.103 (3) | 0.051 (2) | 0.0322 (15) | 0.0285 (19) | −0.0013 (16) | 0.0088 (14) |
| N2 | 0.0567 (18) | 0.0399 (16) | 0.0296 (14) | 0.0083 (13) | −0.0010 (12) | 0.0127 (12) |
| N3 | 0.084 (2) | 0.0411 (18) | 0.0469 (17) | −0.0106 (16) | −0.0191 (16) | 0.0181 (15) |
| N4 | 0.062 (2) | 0.0385 (16) | 0.0464 (17) | −0.0001 (14) | −0.0092 (14) | 0.0207 (14) |
| N5 | 0.062 (2) | 0.079 (3) | 0.081 (3) | 0.0151 (19) | 0.0075 (19) | 0.041 (2) |
| N6 | 0.074 (2) | 0.0438 (18) | 0.0476 (18) | 0.0091 (15) | 0.0171 (16) | 0.0181 (15) |
| O1 | 0.113 (2) | 0.0510 (16) | 0.0310 (12) | 0.0239 (16) | −0.0190 (14) | 0.0072 (12) |
| O2 | 0.125 (3) | 0.0538 (17) | 0.0457 (15) | −0.0128 (17) | −0.0233 (16) | 0.0281 (14) |
| O3 | 0.153 (4) | 0.094 (3) | 0.108 (3) | 0.067 (3) | 0.014 (3) | 0.049 (2) |
| O4 | 0.097 (2) | 0.0467 (16) | 0.0417 (14) | −0.0024 (14) | 0.0025 (14) | 0.0150 (13) |
| C1 | 0.067 (2) | 0.0349 (18) | 0.0308 (16) | 0.0060 (16) | −0.0036 (16) | 0.0105 (14) |
| C2 | 0.0447 (19) | 0.0359 (18) | 0.0297 (16) | 0.0021 (14) | −0.0026 (13) | 0.0090 (14) |
| C3 | 0.057 (2) | 0.0401 (19) | 0.0380 (18) | 0.0119 (16) | 0.0013 (15) | 0.0168 (15) |
| C4 | 0.067 (2) | 0.053 (2) | 0.0384 (18) | 0.0134 (18) | 0.0000 (17) | 0.0252 (17) |
| C5 | 0.065 (2) | 0.050 (2) | 0.0280 (16) | 0.0102 (17) | 0.0010 (15) | 0.0142 (16) |
| C6 | 0.0424 (18) | 0.0341 (17) | 0.0315 (16) | 0.0016 (13) | −0.0021 (13) | 0.0148 (14) |
| C7 | 0.060 (2) | 0.041 (2) | 0.0445 (19) | 0.0041 (16) | −0.0108 (16) | 0.0180 (16) |
| C8 | 0.048 (2) | 0.0393 (18) | 0.0399 (18) | 0.0020 (15) | −0.0030 (15) | 0.0198 (15) |
| C9 | 0.080 (3) | 0.040 (2) | 0.051 (2) | −0.0009 (18) | −0.0083 (19) | 0.0255 (18) |
| C10 | 0.101 (3) | 0.052 (2) | 0.046 (2) | −0.004 (2) | −0.019 (2) | 0.0288 (19) |
| C11 | 0.081 (3) | 0.052 (2) | 0.044 (2) | −0.001 (2) | −0.0196 (19) | 0.0210 (19) |
| C12 | 0.0416 (18) | 0.0377 (18) | 0.0389 (17) | 0.0032 (14) | −0.0027 (14) | 0.0200 (15) |
| C13 | 0.086 (4) | 0.098 (5) | 0.256 (9) | 0.029 (3) | 0.059 (5) | 0.112 (6) |
| C14 | 0.077 (4) | 0.134 (5) | 0.101 (4) | −0.006 (3) | 0.000 (3) | 0.061 (4) |
| C15 | 0.088 (4) | 0.097 (4) | 0.076 (3) | 0.030 (3) | 0.008 (3) | 0.033 (3) |
| C16 | 0.102 (4) | 0.050 (3) | 0.081 (3) | −0.009 (2) | 0.031 (3) | 0.004 (2) |
| C17 | 0.089 (4) | 0.091 (4) | 0.086 (3) | 0.016 (3) | 0.012 (3) | 0.064 (3) |
| C18 | 0.080 (3) | 0.055 (2) | 0.0370 (19) | 0.007 (2) | 0.0086 (18) | 0.0202 (19) |
Geometric parameters (Å, °) top
| Se1—C12 | 1.918 (3) | C3—C4 | 1.379 (5) |
| Se1—Se1i | 2.3889 (8) | C3—H3 | 0.9300 |
| Se2—C6 | 1.919 (3) | C4—C5 | 1.365 (5) |
| Se2—Se2ii | 2.3877 (7) | C4—H4 | 0.9300 |
| N1—C1 | 1.312 (4) | C5—H5 | 0.9300 |
| N1—H1A | 0.8600 | C7—C8 | 1.484 (5) |
| N1—H1B | 0.8600 | C8—C9 | 1.383 (5) |
| N2—C6 | 1.336 (4) | C8—C12 | 1.403 (5) |
| N2—C5 | 1.346 (4) | C9—C10 | 1.375 (5) |
| N3—C7 | 1.330 (5) | C9—H9 | 0.9300 |
| N3—H3A | 0.8600 | C10—C11 | 1.363 (5) |
| N3—H3B | 0.8600 | C10—H10 | 0.9300 |
| N4—C11 | 1.328 (5) | C11—H11 | 0.9300 |
| N4—C12 | 1.330 (4) | C13—H13A | 0.9600 |
| N5—C15 | 1.313 (6) | C13—H13B | 0.9600 |
| N5—C13 | 1.403 (6) | C13—H13C | 0.9600 |
| N5—C14 | 1.449 (7) | C14—H14A | 0.9600 |
| N6—C18 | 1.311 (5) | C14—H14B | 0.9600 |
| N6—C16 | 1.451 (5) | C14—H14C | 0.9600 |
| N6—C17 | 1.460 (5) | C15—H15 | 0.9300 |
| O1—C1 | 1.233 (4) | C16—H16A | 0.9600 |
| O2—C7 | 1.224 (4) | C16—H16B | 0.9600 |
| O3—C15 | 1.210 (6) | C16—H16C | 0.9600 |
| O4—C18 | 1.229 (5) | C17—H17A | 0.9600 |
| C1—C2 | 1.487 (4) | C17—H17B | 0.9600 |
| C2—C3 | 1.385 (4) | C17—H17C | 0.9600 |
| C2—C6 | 1.406 (4) | C18—H18 | 0.9300 |
| | | |
| C12—Se1—Se1i | 92.21 (10) | C10—C9—H9 | 120.1 |
| C6—Se2—Se2ii | 92.67 (9) | C8—C9—H9 | 120.1 |
| C1—N1—H1A | 120.0 | C11—C10—C9 | 118.6 (3) |
| C1—N1—H1B | 120.0 | C11—C10—H10 | 120.7 |
| H1A—N1—H1B | 120.0 | C9—C10—H10 | 120.7 |
| C6—N2—C5 | 117.6 (3) | N4—C11—C10 | 123.3 (4) |
| C7—N3—H3A | 120.0 | N4—C11—H11 | 118.3 |
| C7—N3—H3B | 120.0 | C10—C11—H11 | 118.3 |
| H3A—N3—H3B | 120.0 | N4—C12—C8 | 122.6 (3) |
| C11—N4—C12 | 118.4 (3) | N4—C12—Se1 | 116.3 (2) |
| C15—N5—C13 | 123.2 (5) | C8—C12—Se1 | 121.1 (2) |
| C15—N5—C14 | 118.6 (5) | N5—C13—H13A | 109.5 |
| C13—N5—C14 | 118.2 (5) | N5—C13—H13B | 109.5 |
| C18—N6—C16 | 121.4 (4) | H13A—C13—H13B | 109.5 |
| C18—N6—C17 | 119.9 (4) | N5—C13—H13C | 109.5 |
| C16—N6—C17 | 118.6 (4) | H13A—C13—H13C | 109.5 |
| O1—C1—N1 | 121.8 (3) | H13B—C13—H13C | 109.5 |
| O1—C1—C2 | 119.4 (3) | N5—C14—H14A | 109.5 |
| N1—C1—C2 | 118.8 (3) | N5—C14—H14B | 109.5 |
| C3—C2—C6 | 117.2 (3) | H14A—C14—H14B | 109.5 |
| C3—C2—C1 | 122.8 (3) | N5—C14—H14C | 109.5 |
| C6—C2—C1 | 120.0 (3) | H14A—C14—H14C | 109.5 |
| C4—C3—C2 | 120.6 (3) | H14B—C14—H14C | 109.5 |
| C4—C3—H3 | 119.7 | O3—C15—N5 | 127.4 (5) |
| C2—C3—H3 | 119.7 | O3—C15—H15 | 116.3 |
| C5—C4—C3 | 117.8 (3) | N5—C15—H15 | 116.3 |
| C5—C4—H4 | 121.1 | N6—C16—H16A | 109.5 |
| C3—C4—H4 | 121.1 | N6—C16—H16B | 109.5 |
| N2—C5—C4 | 124.0 (3) | H16A—C16—H16B | 109.5 |
| N2—C5—H5 | 118.0 | N6—C16—H16C | 109.5 |
| C4—C5—H5 | 118.0 | H16A—C16—H16C | 109.5 |
| N2—C6—C2 | 122.7 (3) | H16B—C16—H16C | 109.5 |
| N2—C6—Se2 | 116.1 (2) | N6—C17—H17A | 109.5 |
| C2—C6—Se2 | 121.2 (2) | N6—C17—H17B | 109.5 |
| O2—C7—N3 | 122.0 (3) | H17A—C17—H17B | 109.5 |
| O2—C7—C8 | 120.0 (3) | N6—C17—H17C | 109.5 |
| N3—C7—C8 | 118.0 (3) | H17A—C17—H17C | 109.5 |
| C9—C8—C12 | 117.2 (3) | H17B—C17—H17C | 109.5 |
| C9—C8—C7 | 123.0 (3) | O4—C18—N6 | 125.9 (4) |
| C12—C8—C7 | 119.8 (3) | O4—C18—H18 | 117.0 |
| C10—C9—C8 | 119.9 (3) | N6—C18—H18 | 117.0 |
| Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) −x, −y+2, −z+2. |
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1A···O4 | 0.86 | 2.09 | 2.946 (4) | 170 |
| N1—H1B···O3 | 0.86 | 2.03 | 2.869 (5) | 163 |
| N3—H3B···O4 | 0.86 | 2.10 | 2.919 (4) | 158 |
| N3—H3A···O1iii | 0.86 | 2.31 | 3.081 (4) | 150 |
| Symmetry codes: (iii) −x, −y+1, −z+1. |
Table 1
Hydrogen-bond geometry (Å, °) top
| D—H···A | D—H | H···A | D···A | D—H···A |
| N1—H1A···O4 | 0.86 | 2.09 | 2.946 (4) | 170 |
| N1—H1B···O3 | 0.86 | 2.03 | 2.869 (5) | 163 |
| N3—H3B···O4 | 0.86 | 2.10 | 2.919 (4) | 158 |
| N3—H3A···O1i | 0.86 | 2.31 | 3.081 (4) | 150 |
| Symmetry codes: (i) −x, −y+1, −z+1. |
We thank the SNSF (Nos. 2008011021 and 2008012013-2) and the Homecoming
Foundation of Shanxi Province for support.
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Mugesh, G., Mont, W.-W. & Sies, H. (2001). Chem. Rev. 101, 2125–2179.
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Siemens (1996). SMART and SAINT. Siemens Analytical X-ray Instruments Inc., Madison, Wisconsin, USA.
Organoselenium compounds have attracted much atention because of their potential applications in organic synthesis, precursors for semiconducting materials, ligand chemistry and biochemistry (Mugesh et al., 2001). During the past decade, many organoselenium compounds have been synthesized and well characterized. In contrast to alkyl, aryl, and mixed alkylaryl senium compounds, the pyridyl selenium compounds are still rare.
The unit cell contains two nicotinamide molecules and four of the solvent molecules. The asymmetric unit contains two solvent molecules and two half molecues of the nicotinamide each of which sits on a center of symmetry passing through the middle of the Se—Se bond (Fig. 1). In (I),the two independent nicotinamides (molecule A containing Se1 and molecule B containing Se2) have comparable conformations. In each nicotinamide, the two pyridyl groups and the diseleno group are approximately coplanar (r.m.s. deviations from planarity for all non-H atoms are 0.011 and 0.008Å for molecules A and B, respectively while the two CONH2 groups are rotated out of this plane by 11.0 (5)° and 18.6 (5)° for molecules A and B, respectively. Fig. 2 shows the sheets of molecules formed by intermolecular N-H···O hydrogen-bond interactions between the nicotinamides and neighbouring solvents with distances between 2.869 (5) and 3.081 (4) Å (Table 1).
The structure of (I) is similar to that of other diselenide compounds (Kienitz, et al. 1996; Bhasin and Singh 2002).The two neighbouring pyridyl groups can be brought into register by rotation about the Se—Se bond. The commonly observed approximate coplanarity of the rings and the Se—Se bonds (C—C—Se—Se or N—C—Se—Se torsion angles ca. 0°) in these molecules has been explained in terms of a minimization of Se···Se lone pair repulsion.