Effects of structural variations on the optical and electronic properties of eumelanin-inspired small molecules
Subhashini Selvaraju; Santosh Adhikari; RaiAnna A. Hopson; Shuo Dai; Arnold L. Rheingold; Mario F. Borunda; Toby L. Nelson; Journal of Materials Chemistry C 4 (2016) 3995–3999; doi:10.1039/C5TC03982G

data_7234724
_publ_section_title
;
 Effects of structural variations on the optical and electronic properties
 of eumelanin-inspired small molecules
;
_journal_name_full               'Journal of Materials Chemistry C'
_journal_page_first              3995
_journal_page_last               3999
_journal_paper_doi               10.1039/C5TC03982G
_journal_volume                  4
_journal_year                    2016
_chemical_formula_sum            'C29 H21 F2 N O4'
_chemical_formula_weight         485.47
_chemical_name_systematic        Nelson002
_space_group_crystal_system      orthorhombic
_space_group_IT_number           29
_space_group_name_Hall           'P 2c -2ac'
_space_group_name_H-M_alt        'P c a 21'
_atom_sites_solution_hydrogens   geom
_cell_angle_alpha                90
_cell_angle_beta                 90
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   23.809(4)
_cell_length_b                   13.756(3)
_cell_length_c                   7.2297(12)
_cell_measurement_reflns_used    2133
_cell_measurement_temperature    100(2)
_cell_measurement_theta_max      22.17
_cell_measurement_theta_min      2.26
_cell_volume                     2367.8(8)
_computing_cell_refinement       'Bruker SAINT'
_computing_data_collection       'Bruker APEX2'
_computing_data_reduction        'Bruker SAINT'
_computing_molecular_graphics    'Bruker SHELXTL'
_computing_publication_material  'Bruker SHELXTL'
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_computing_structure_solution    'SHELXS-97 (Sheldrick 2008)'
_diffrn_ambient_temperature      100(2)
_diffrn_measured_fraction_theta_full 0.816
_diffrn_measured_fraction_theta_max 0.993
_diffrn_measurement_device_type  'Bruker APEX-II CCD'
_diffrn_measurement_method       '\f and \w scans'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0944
_diffrn_reflns_av_unetI/netI     0.1533
_diffrn_reflns_Laue_measured_fraction_full 0.816
_diffrn_reflns_Laue_measured_fraction_max 0.993
_diffrn_reflns_limit_h_max       26
_diffrn_reflns_limit_h_min       -24
_diffrn_reflns_limit_k_max       15
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       8
_diffrn_reflns_limit_l_min       -8
_diffrn_reflns_number            4831
_diffrn_reflns_point_group_measured_fraction_full 0.606
_diffrn_reflns_point_group_measured_fraction_max 0.742
_diffrn_reflns_theta_full        25.000
_diffrn_reflns_theta_max         23.286
_diffrn_reflns_theta_min         1.710
_exptl_absorpt_coefficient_mu    0.101
_exptl_absorpt_correction_T_max  0.944
_exptl_absorpt_correction_T_min  0.909
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   SADABS
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.362
_exptl_crystal_description       plate
_exptl_crystal_F_000             1008
_exptl_crystal_size_max          0.300
_exptl_crystal_size_mid          0.100
_exptl_crystal_size_min          0.050
_refine_diff_density_max         0.333
_refine_diff_density_min         -0.233
_refine_diff_density_rms         0.064
_refine_ls_abs_structure_details
; 
 Flack x determined using 326 quotients [(I+)-(I-)]/[(I+)+(I-)] 
 (Parsons and Flack (2004), Acta Cryst. A60, s61). 
;
_refine_ls_abs_structure_Flack   0.2(10)
_refine_ls_extinction_coef       0.0060(18)
_refine_ls_extinction_expression Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^
_refine_ls_extinction_method     SHELXL
_refine_ls_goodness_of_fit_ref   0.942
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     330
_refine_ls_number_reflns         2531
_refine_ls_number_restraints     1
_refine_ls_restrained_S_all      0.942
_refine_ls_R_factor_all          0.1051
_refine_ls_R_factor_gt           0.0671
_refine_ls_shift/su_max          0.003
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0010P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1461
_refine_ls_wR_factor_ref         0.1652
_reflns_Friedel_coverage         0.364
_reflns_Friedel_fraction_full    0.355
_reflns_Friedel_fraction_max     0.438
_reflns_number_gt                1670
_reflns_number_total             2531
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            J-Mater-Chem-C-2016-4-3995.cif
_cod_data_source_block           nelson02
_cod_original_cell_volume        2367.9(7)
_cod_database_code               7234724
_shelx_estimated_absorpt_t_min   0.970
_shelx_estimated_absorpt_t_max   0.995
_shelxl_version_number           2013-3
_shelx_res_checksum              38946
_shelx_hkl_checksum              6605