Diamidocarbenes as versatile and reversible [2 + 1] cycloaddition reagents.
Moerdyk, Jonathan P.; Bielawski, Christopher W.; Nature chemistry 4 (2012) 275–280; doi:10.1038/nchem.1267

data_1508177
_publ_section_title
;
 Diamidocarbenes as versatile and reversible [2 + 1] cycloaddition
 reagents.
;
_journal_issue                   4
_journal_name_full               'Nature chemistry'
_journal_page_first              275
_journal_page_last               280
_journal_paper_doi               10.1038/nchem.1267
_journal_volume                  4
_journal_year                    2012
_chemical_formula_moiety
cis-4,8-Mes2-6,6-Me2-5,7-dioxo-4,8-diazaspiro[2.5]octane-1,2-dicarbonitrile
_chemical_formula_sum            'C28 H30 N4 O2'
_chemical_formula_weight         454.56
_chemical_name_common            6MesDACMaleonitrile
_space_group_IT_number           14
_symmetry_cell_setting           monoclinic
_symmetry_space_group_name_Hall  '-P 2yn'
_symmetry_space_group_name_H-M   'P 1 21/n 1'
_atom_sites_solution_hydrogens   geom
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-97
_cell_angle_alpha                90.00
_cell_angle_beta                 101.1470(10)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   15.3430(2)
_cell_length_b                   10.7550(2)
_cell_length_c                   15.6115(3)
_cell_measurement_temperature    120(2)
_cell_volume                     2527.52(8)
_computing_cell_refinement       'CrystalClear (Rigaku Inc., 2008)'
_computing_data_collection       'CrystalClear (Rigaku Inc., 2008)'
_computing_data_reduction        'CrystalClear (Rigaku Inc., 2008)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      120(2)
_diffrn_measured_fraction_theta_full 0.982
_diffrn_measured_fraction_theta_max 0.982
_diffrn_measurement_device_type  'CCD area detector'
_diffrn_measurement_method       'phi and omega scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0291
_diffrn_reflns_av_sigmaI/netI    0.0465
_diffrn_reflns_limit_h_max       19
_diffrn_reflns_limit_h_min       -19
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       20
_diffrn_reflns_limit_l_min       -20
_diffrn_reflns_number            9766
_diffrn_reflns_theta_full        27.48
_diffrn_reflns_theta_max         27.48
_diffrn_reflns_theta_min         3.27
_exptl_absorpt_coefficient_mu    0.077
_exptl_absorpt_correction_type   none
_exptl_absorpt_process_details   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.195
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       blocks
_exptl_crystal_F_000             968
_exptl_crystal_size_max          0.26
_exptl_crystal_size_mid          0.24
_exptl_crystal_size_min          0.19
_refine_diff_density_max         0.213
_refine_diff_density_min         -0.201
_refine_diff_density_rms         0.047
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.006
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     315
_refine_ls_number_reflns         5687
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.006
_refine_ls_R_factor_all          0.0982
_refine_ls_R_factor_gt           0.0561
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.0502P)^2^+1.9082P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1159
_refine_ls_wR_factor_ref         0.1402
_reflns_number_gt                3884
_reflns_number_total             5687
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            nchem.1267-s5.cif
_cod_data_source_block           DACMaleonitrile/2m
_cod_depositor_comments
;
The following automatic conversions were performed:

'_symmetry_cell_setting' value 'Monoclinic' changed to 'monoclinic'
according to /home/saulius/struct/CIF-dictionaries/cif_core.dic
dictionary named 'cif_core.dic' version 2.4.1 from 2010-06-29.

Automatic conversion script
Id: cif_fix_values 1891 2012-01-12 08:04:46Z andrius 
;
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               1508177