Synthesis, resolution, and stabilities of a cationic chromenoxanthene [4]helicene.
Guin, Joyram; Besnard, Céline; Lacour, Jérôme; Organic letters 12 (2010) 1748–1751; doi:10.1021/ol1003466

data_1502912
_publ_contact_author
;
     Prof. Jerome Lacour
     Department of Organic Chemistry
     University of Geneva
     30, quai E. Ansermet
     CH - 1212 Geneva 4
     Switzerland
;
_publ_section_title
;
 Synthesis, resolution, and stabilities of a cationic chromenoxanthene
 [4]helicene.
;
_journal_issue                   8
_journal_name_full               'Organic letters'
_journal_page_first              1748
_journal_page_last               1751
_journal_paper_doi               10.1021/ol1003466
_journal_volume                  12
_journal_year                    2010
_chemical_formula_moiety         'C21 H16 O4'
_chemical_formula_sum            'C21 H16 O4'
_chemical_formula_weight         332.36
_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
_cell_angle_alpha                90
_cell_angle_beta                 100.174(10)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   13.3623(10)
_cell_length_b                   8.7047(4)
_cell_length_c                   13.9012(12)
_cell_measurement_reflns_used    8000
_cell_measurement_temperature    150
_cell_measurement_theta_max      32.9
_cell_measurement_theta_min      3.3
_cell_volume                     1591.5(2)
_computing_cell_refinement       'IPDS (Stoe & Cie, 1996)'
_computing_data_collection       'IPDS (Stoe & Cie, 1996)'
_computing_data_reduction        'XRED (Stoe & Cie 1996)'
_computing_molecular_graphics    'CAMERON (Watkin et al., 1996)'
_computing_publication_material  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_refinement  'CRYSTALS (Betteridge et al., 2003)'
_computing_structure_solution    'Sir2004 (Burla et al., 2005)'
_diffrn_ambient_temperature      150
_diffrn_measured_fraction_theta_full 0.986
_diffrn_measured_fraction_theta_max 0.962
_diffrn_measurement_device       'Stoe IPDS'
_diffrn_measurement_device_type  Area
_diffrn_measurement_method       '\f scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.115
_diffrn_reflns_limit_h_max       20
_diffrn_reflns_limit_h_min       -20
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       0
_diffrn_reflns_limit_l_max       21
_diffrn_reflns_limit_l_min       0
_diffrn_reflns_number            28197
_diffrn_reflns_theta_full        26.338
_diffrn_reflns_theta_max         32.944
_diffrn_reflns_theta_min         3.303
_diffrn_standards_number         0
_exptl_absorpt_coefficient_mu    0.096
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    1.387
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             696
_exptl_crystal_size_max          0.400
_exptl_crystal_size_mid          0.300
_exptl_crystal_size_min          0.300
_refine_diff_density_max         0.37
_refine_diff_density_min         -0.35
_refine_ls_extinction_method     None
_refine_ls_goodness_of_fit_ref   0.9429
_refine_ls_hydrogen_treatment    none
_refine_ls_matrix_type           full
_refine_ls_number_parameters     226
_refine_ls_number_reflns         2946
_refine_ls_number_restraints     0
_refine_ls_R_factor_all          0.0664
_refine_ls_R_factor_gt           0.0363
_refine_ls_shift/su_max          0.0003634
_refine_ls_shift/su_mean         0.9124632
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 Method, part 1, Chebychev polynomial, (Watkin, 1994, Prince, 1982) 
 [weight] = 1.0/[A~0~*T~0~(x)+A~1~*T~1~(x) ... +A~n-1~]*T~n-1~(x)] 
 where A~i~ are the Chebychev coefficients listed below and x= Fcalc/Fmax 
 Method = Robust Weighting (Prince, 1982) 
 W = [weight] * [1-(deltaF/6*sigmaF)^2^]^2^ 
 A~i~ are: 
 1.45 1.32 0.142 
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_all         0.0680
_refine_ls_wR_factor_gt          0.0556
_refine_ls_wR_factor_ref         0.0679
_reflns_limit_h_max              20
_reflns_limit_h_min              -20
_reflns_limit_k_max              12
_reflns_limit_k_min              0
_reflns_limit_l_max              21
_reflns_limit_l_min              0
_reflns_number_gt                1842
_reflns_number_total             2947
_reflns_threshold_expression     I>2.0\s(I)
_oxford_diffrn_Wilson_B_factor   2.07
_oxford_diffrn_Wilson_scale      27.51
_oxford_refine_ls_r_factor_ref   0.0662
_oxford_refine_ls_scale          0.22217(11)
_oxford_reflns_number_all        2947
_oxford_reflns_threshold_expression_ref I>-1.0\s(I)
_cod_data_source_file            ol1003466_si_002.cif
_cod_data_source_block           JOY218
_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 2.4.2 from 2011-04-26.

Automatic conversion script
Id: cif_fix_values 1715 2011-07-08 13:25:40Z adriana 
;
_cod_original_sg_symbol_Hall     '-P 2yn '
_cod_original_sg_symbol_H-M      'P 1 21/n 1 '
_cod_database_code               1502912