Electronic Supplementary Material for CrystEngComm
This Journal is (c) The Royal Society of Chemistry 2007

data_global
_journal_name_full               CrystEngComm
_journal_coden_cambridge         1350

_publ_contact_author             
;Prof. A Nangia
School of Chemistry
University of Hyderabad
P O Central University
Hyderabad
500046
INDIA
;
_publ_contact_author_email       'ASHWINI NANGIA@REDIFFMAIL.COM'
_publ_contact_author_name        'Prof. A Nangia'
loop_
_publ_author_name
A.Nangia
'N. Jagadeesh Babu '

data_pnma
_database_code_depnum_ccdc_archive 'CCDC 648204'

_audit_creation_method           SHELXL-97
_chemical_name_systematic        
;
Pyrazine-N,N'-dioxide
;
_chemical_name_common            Pyrazine-N,N'-dioxide
_chemical_melting_point          '560K (decomp) '
_chemical_formula_moiety         ' C2 H2 N O, 0.5(C4 H4 N2 O2)'
_chemical_formula_sum            'C4 H4 N2 O2'
_chemical_formula_weight         112.09

loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
C C 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
H H 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
N N 0.0061 0.0033 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
O O 0.0106 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'

_symmetry_cell_setting           Orthorhombic
_symmetry_space_group_name_H-M   'Pnma '

loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
'-x+1/2, -y, z+1/2'
'-x, y+1/2, -z'
'x+1/2, -y+1/2, -z+1/2'
'-x, -y, -z'
'x-1/2, y, -z-1/2'
'x, -y-1/2, z'
'-x-1/2, y-1/2, z-1/2'

_cell_length_a                   11.8672(18)
_cell_length_b                   12.2217(19)
_cell_length_c                   6.4287(10)
_cell_angle_alpha                90.00
_cell_angle_beta                 90.00
_cell_angle_gamma                90.00
_cell_volume                     932.4(2)
_cell_formula_units_Z            8
_cell_measurement_temperature    293(2)
_cell_measurement_reflns_used    1512
_cell_measurement_theta_min      3.33
_cell_measurement_theta_max      25.94

_exptl_crystal_description       plate
_exptl_crystal_colour            colourless
_exptl_crystal_size_max          0.41
_exptl_crystal_size_mid          0.21
_exptl_crystal_size_min          0.06
_exptl_crystal_density_meas      ?
_exptl_crystal_density_diffrn    1.597
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             464
_exptl_absorpt_coefficient_mu    0.131
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_correction_T_min  0.9482
_exptl_absorpt_correction_T_max  0.9922
_exptl_absorpt_process_details   'Bruker AXS SADABS program'

_exptl_special_details           
;
Sheldrick,G.M.,(2003),University of gottingen,Germany
;

_diffrn_ambient_temperature      293(2)
_diffrn_radiation_wavelength     0.71073
_diffrn_radiation_type           MoK\a
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_monochromator  graphite
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_detector_area_resol_mean ?
_diffrn_standards_number         ?
_diffrn_standards_interval_count ?
_diffrn_standards_interval_time  ?
_diffrn_standards_decay_%        ?
_diffrn_reflns_number            4790
_diffrn_reflns_av_R_equivalents  0.0312
_diffrn_reflns_av_sigmaI/netI    0.0217
_diffrn_reflns_limit_h_min       -14
_diffrn_reflns_limit_h_max       12
_diffrn_reflns_limit_k_min       -14
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_limit_l_max       7
_diffrn_reflns_theta_min         3.33
_diffrn_reflns_theta_max         26.01
_reflns_number_total             956
_reflns_number_gt                643
_reflns_threshold_expression     >2sigma(I)

_computing_data_collection       'Bruker SMART'
_computing_cell_refinement       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'

_refine_special_details          
;
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^ > 2sigma(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.
;

_refine_ls_structure_factor_coef Fsqd
_refine_ls_matrix_type           full
_refine_ls_weighting_scheme      calc
_refine_ls_weighting_details     
'calc w=1/[\s^2^(Fo^2^)+(0.0730P)^2^+0.2522P] where P=(Fo^2^+2Fc^2^)/3'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_atom_sites_solution_hydrogens   geom
_refine_ls_hydrogen_treatment    constr
_refine_ls_extinction_method     none
_refine_ls_extinction_coef       ?
_refine_ls_number_reflns         956
_refine_ls_number_parameters     85
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0874
_refine_ls_R_factor_gt           0.0605
_refine_ls_wR_factor_ref         0.1584
_refine_ls_wR_factor_gt          0.1439
_refine_ls_goodness_of_fit_ref   1.151
_refine_ls_restrained_S_all      1.151
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_symmetry_multiplicity
_atom_site_calc_flag
_atom_site_refinement_flags
_atom_site_disorder_assembly
_atom_site_disorder_group
N2 N 0.5620(2) 0.2500 0.1955(4) 0.0328(7) Uani 1 2 d S . .
O2 O 0.4985(2) 0.2500 0.3607(4) 0.0466(7) Uani 1 2 d S . .
O1 O 0.7642(2) 0.2500 -0.3092(4) 0.0714(10) Uani 1 2 d S . .
C1 C 0.7432(3) 0.2500 0.0447(5) 0.0381(9) Uani 1 2 d S . .
H1 H 0.8211 0.2500 0.0613 0.046 Uiso 1 2 calc SR . .
C3 C 0.5188(3) 0.2500 0.0012(5) 0.0368(9) Uani 1 2 d S . .
H3 H 0.4410 0.2500 -0.0157 0.044 Uiso 1 2 calc SR . .
C2 C 0.6762(3) 0.2500 0.2151(5) 0.0369(9) Uani 1 2 d S . .
H2 H 0.7085 0.2500 0.3469 0.044 Uiso 1 2 calc SR . .
N1 N 0.6989(2) 0.2500 -0.1494(4) 0.0424(8) Uani 1 2 d S . .
C4 C 0.5847(3) 0.2500 -0.1677(5) 0.0424(9) Uani 1 2 d S . .
H4 H 0.5520 0.2500 -0.2992 0.051 Uiso 1 2 calc SR . .
O3 O 0.36647(16) 0.49092(17) 0.1660(3) 0.0577(7) Uani 1 1 d . . .
N3 N 0.43087(18) 0.49625(16) 0.3286(3) 0.0365(6) Uani 1 1 d . . .
C5 C 0.3878(2) 0.4920(2) 0.5233(4) 0.0378(7) Uani 1 1 d . . .
H5 H 0.3103 0.4869 0.5413 0.045 Uiso 1 1 calc R . .
C6 C 0.5444(2) 0.50498(19) 0.3080(4) 0.0370(7) Uani 1 1 d . . .
H6 H 0.5760 0.5089 0.1758 0.044 Uiso 1 1 calc R . .

loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_23
_atom_site_aniso_U_13
_atom_site_aniso_U_12
N2 0.0243(15) 0.0462(17) 0.0279(15) 0.000 0.0006(11) 0.000
O2 0.0301(14) 0.0754(19) 0.0343(13) 0.000 0.0105(10) 0.000
O1 0.0403(17) 0.140(3) 0.0341(16) 0.000 0.0142(12) 0.000
C1 0.0231(18) 0.055(2) 0.036(2) 0.000 -0.0004(14) 0.000
C3 0.0213(17) 0.052(2) 0.0370(19) 0.000 -0.0024(14) 0.000
C2 0.0237(17) 0.054(2) 0.0334(19) 0.000 -0.0026(14) 0.000
N1 0.0313(17) 0.065(2) 0.0307(16) 0.000 0.0012(12) 0.000
C4 0.035(2) 0.061(2) 0.0313(19) 0.000 -0.0070(16) 0.000
O3 0.0364(12) 0.1026(18) 0.0342(11) -0.0040(11) -0.0122(8) -0.0007(10)
N3 0.0259(11) 0.0541(14) 0.0296(11) -0.0031(9) -0.0036(8) 0.0006(9)
C5 0.0223(12) 0.0509(15) 0.0402(14) -0.0035(12) 0.0028(10) -0.0013(10)
C6 0.0268(14) 0.0526(16) 0.0315(13) -0.0011(11) 0.0076(10) -0.0009(10)

_geom_special_details            
;
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.
;

loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_distance
_geom_bond_site_symmetry_2
_geom_bond_publ_flag
N2 O2 1.302(3) . ?
N2 C3 1.350(4) . ?
N2 C2 1.361(4) . ?
O1 N1 1.287(3) . ?
C1 C2 1.354(5) . ?
C1 N1 1.354(4) . ?
C1 H1 0.9300 . ?
C3 C4 1.338(5) . ?
C3 H3 0.9300 . ?
C2 H2 0.9300 . ?
N1 C4 1.361(4) . ?
C4 H4 0.9300 . ?
O3 N3 1.297(2) . ?
N3 C5 1.353(3) . ?
N3 C6 1.358(3) . ?
C5 C6 1.350(4) 5_666 ?
C5 H5 0.9300 . ?
C6 C5 1.350(4) 5_666 ?
C6 H6 0.9300 . ?

loop_
_geom_angle_atom_site_label_1
_geom_angle_atom_site_label_2
_geom_angle_atom_site_label_3
_geom_angle
_geom_angle_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle_publ_flag
O2 N2 C3 122.3(3) . . ?
O2 N2 C2 120.0(3) . . ?
C3 N2 C2 117.6(3) . . ?
C2 C1 N1 121.2(3) . . ?
C2 C1 H1 119.4 . . ?
N1 C1 H1 119.4 . . ?
C4 C3 N2 122.0(3) . . ?
C4 C3 H3 119.0 . . ?
N2 C3 H3 119.0 . . ?
C1 C2 N2 120.7(3) . . ?
C1 C2 H2 119.7 . . ?
N2 C2 H2 119.7 . . ?
O1 N1 C1 120.1(3) . . ?
O1 N1 C4 122.1(3) . . ?
C1 N1 C4 117.8(3) . . ?
C3 C4 N1 120.8(3) . . ?
C3 C4 H4 119.6 . . ?
N1 C4 H4 119.6 . . ?
O3 N3 C5 121.4(2) . . ?
O3 N3 C6 120.7(2) . . ?
C5 N3 C6 117.9(2) . . ?
C6 C5 N3 121.2(2) 5_666 . ?
C6 C5 H5 119.4 5_666 . ?
N3 C5 H5 119.4 . . ?
C5 C6 N3 120.9(2) 5_666 . ?
C5 C6 H6 119.5 5_666 . ?
N3 C6 H6 119.5 . . ?

_diffrn_measured_fraction_theta_max 1.000
_diffrn_reflns_theta_full        26.01
_diffrn_measured_fraction_theta_full 1.000
_refine_diff_density_max         0.223
_refine_diff_density_min         -0.314
_refine_diff_density_rms         0.060

# Attachment 'form-2.cif'

data_an639c_m
_database_code_depnum_ccdc_archive 'CCDC 648205'

_audit_creation_method           SHELXL-97
_chemical_name_systematic        
;
Pyrazine-N,N'-dioxide
;
_chemical_name_common            Pyrazine-N,N'-dioxide
_chemical_melting_point          '557K (decomp) '
_chemical_formula_moiety         'C4 H4 N2 O2'
_chemical_formula_sum            'C4 H4 N2 O2'
_chemical_formula_weight         112.09

loop_
_atom_type_symbol
_atom_type_description
_atom_type_scat_dispersion_real
_atom_type_scat_dispersion_imag
_atom_type_scat_source
C C 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
H H 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
N N 0.0061 0.0033 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'
O O 0.0106 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4'

_symmetry_cell_setting           Monoclinic
_symmetry_space_group_name_H-M   'p 2 1/c '

loop_
_symmetry_equiv_pos_as_xyz
'x, y, z'
'-x, y+1/2, -z+1/2'
'-x, -y, -z'
'x, -y-1/2, z-1/2'

_cell_length_a                   3.7239(13)
_cell_length_b                   11.010(4)
_cell_length_c                   5.683(2)
_cell_angle_alpha                90.00
_cell_angle_beta                 96.237(5)
_cell_angle_gamma                90.00
_cell_volume                     231.62(14)
_cell_formula_units_Z            2
_cell_measurement_temperature    293(2)
_cell_measurement_reflns_used    1174
_cell_measurement_theta_min      3.70
_cell_measurement_theta_max      25.91

_exptl_crystal_description       plate
_exptl_crystal_colour            colourless
_exptl_crystal_size_max          0.48
_exptl_crystal_size_mid          0.20
_exptl_crystal_size_min          0.02
_exptl_crystal_density_meas      ?
_exptl_crystal_density_diffrn    1.607
_exptl_crystal_density_method    'not measured'
_exptl_crystal_F_000             116
_exptl_absorpt_coefficient_mu    0.132
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_correction_T_min  0.9394
_exptl_absorpt_correction_T_max  0.9974
_exptl_absorpt_process_details   'Bruker AXS SADABS program'

_exptl_special_details           
;
Sheldrick,G.M.,(2003),University of gottingen,Germany
;

_diffrn_ambient_temperature      293(2)
_diffrn_radiation_wavelength     0.71073
_diffrn_radiation_type           MoK\a
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_monochromator  graphite
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_detector_area_resol_mean ?
_diffrn_standards_number         ?
_diffrn_standards_interval_count ?
_diffrn_standards_interval_time  ?
_diffrn_standards_decay_%        ?
_diffrn_reflns_number            2286
_diffrn_reflns_av_R_equivalents  0.0293
_diffrn_reflns_av_sigmaI/netI    0.0207
_diffrn_reflns_limit_h_min       -4
_diffrn_reflns_limit_h_max       4
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_l_min       -6
_diffrn_reflns_limit_l_max       6
_diffrn_reflns_theta_min         3.70
_diffrn_reflns_theta_max         25.98
_reflns_number_total             455
_reflns_number_gt                401
_reflns_threshold_expression     >2sigma(I)

_computing_data_collection       'Bruker SMART'
_computing_cell_refinement       'Bruker SMART'
_computing_data_reduction        'Bruker SAINT'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'

_refine_special_details          
;
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^ > 2sigma(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.
;

_refine_ls_structure_factor_coef Fsqd
_refine_ls_matrix_type           full
_refine_ls_weighting_scheme      calc
_refine_ls_weighting_details     
'calc w=1/[\s^2^(Fo^2^)+(0.0463P)^2^+0.0941P] where P=(Fo^2^+2Fc^2^)/3'
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_atom_sites_solution_hydrogens   geom
_refine_ls_hydrogen_treatment    constr
_refine_ls_extinction_method     none
_refine_ls_extinction_coef       ?
_refine_ls_number_reflns         455
_refine_ls_number_parameters     37
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0651
_refine_ls_R_factor_gt           0.0564
_refine_ls_wR_factor_ref         0.1220
_refine_ls_wR_factor_gt          0.1178
_refine_ls_goodness_of_fit_ref   1.240
_refine_ls_restrained_S_all      1.240
_refine_ls_shift/su_max          0.000
_refine_ls_shift/su_mean         0.000

loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
_atom_site_adp_type
_atom_site_occupancy
_atom_site_symmetry_multiplicity
_atom_site_calc_flag
_atom_site_refinement_flags
_atom_site_disorder_assembly
_atom_site_disorder_group
O1 O 0.9201(5) 0.13590(15) 0.3060(3) 0.0507(6) Uani 1 1 d . . .
N1 N 0.7144(5) 0.06973(17) 0.1585(3) 0.0359(5) Uani 1 1 d . . .
C1 C 0.5745(6) 0.1156(2) -0.0528(4) 0.0388(6) Uani 1 1 d . . .
H1 H 0.6243 0.1955 -0.0915 0.047 Uiso 1 1 calc R . .
C2 C 0.6380(6) -0.0460(2) 0.2089(4) 0.0379(6) Uani 1 1 d . . .
H2 H 0.7321 -0.0791 0.3531 0.046 Uiso 1 1 calc R . .

loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_23
_atom_site_aniso_U_13
_atom_site_aniso_U_12
O1 0.0559(11) 0.0489(11) 0.0426(10) -0.0088(7) -0.0161(8) -0.0013(8)
N1 0.0357(10) 0.0403(10) 0.0305(10) -0.0032(8) -0.0016(8) 0.0041(8)
C1 0.0425(13) 0.0370(12) 0.0365(13) 0.0050(9) 0.0023(10) 0.0040(10)
C2 0.0415(12) 0.0435(13) 0.0278(12) 0.0059(9) -0.0003(10) 0.0066(10)

_geom_special_details            
;
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.
;

loop_
_geom_bond_atom_site_label_1
_geom_bond_atom_site_label_2
_geom_bond_distance
_geom_bond_site_symmetry_2
_geom_bond_publ_flag
O1 N1 1.296(2) . ?
N1 C2 1.343(3) . ?
N1 C1 1.354(3) . ?
C1 C2 1.360(3) 3_655 ?
C1 H1 0.9300 . ?
C2 C1 1.360(3) 3_655 ?
C2 H2 0.9300 . ?

loop_
_geom_angle_atom_site_label_1
_geom_angle_atom_site_label_2
_geom_angle_atom_site_label_3
_geom_angle
_geom_angle_site_symmetry_1
_geom_angle_site_symmetry_3
_geom_angle_publ_flag
O1 N1 C2 121.29(18) . . ?
O1 N1 C1 120.47(19) . . ?
C2 N1 C1 118.23(18) . . ?
N1 C1 C2 120.6(2) . 3_655 ?
N1 C1 H1 119.7 . . ?
C2 C1 H1 119.7 3_655 . ?
N1 C2 C1 121.1(2) . 3_655 ?
N1 C2 H2 119.4 . . ?
C1 C2 H2 119.4 3_655 . ?

_diffrn_measured_fraction_theta_max 1.000
_diffrn_reflns_theta_full        25.98
_diffrn_measured_fraction_theta_full 1.000
_refine_diff_density_max         0.218
_refine_diff_density_min         -0.152
_refine_diff_density_rms         0.055


