Synthesis, X-ray crystal structure, optical properties and DFT studies of a new 2D layered iodide bridged Pb(II) coordination polymer with 2,3-bis(2-pyridyl)pyrazine
Saghatforoush, Lotfali; Bakhtiari, Akbar; Gheleji, Hojjat; Journal of Solid State Chemistry 221 (2015) 433–440; doi:10.1016/j.jssc.2014.10.023

data_1562165
_publ_section_title
;
 Synthesis, X-ray crystal structure, optical properties and DFT studies of
 a new 2D layered iodide bridged Pb(II) coordination polymer with
 2,3-bis(2-pyridyl)pyrazine
;
_journal_name_full               'Journal of Solid State Chemistry'
_journal_page_first              433
_journal_page_last               440
_journal_paper_doi               10.1016/j.jssc.2014.10.023
_journal_volume                  221
_journal_year                    2015
_chemical_formula_sum            'C28 H20 I4 N8 Pb2'
_chemical_formula_weight         1389.49
_space_group_crystal_system      monoclinic
_space_group_IT_number           4
_space_group_name_Hall           'P 2ybc'
_space_group_name_H-M_alt        'P 1 21 1 (a,b,c-1/4)'
_atom_sites_solution_hydrogens   geom
_cell_angle_alpha                90
_cell_angle_beta                 109.674(8)
_cell_angle_gamma                90
_cell_formula_units_Z            2
_cell_length_a                   7.9685(2)
_cell_length_b                   25.2773(5)
_cell_length_c                   9.1700(7)
_cell_measurement_reflns_used    6155
_cell_measurement_temperature    163(2)
_cell_measurement_theta_max      72.0
_cell_measurement_theta_min      6.6
_cell_volume                     1739.22(17)
_computing_structure_refinement  'SHELXL-2013 (Sheldrick, 2013)'
_diffrn_ambient_temperature      163(2)
_diffrn_detector_area_resol_mean 10
_diffrn_measured_fraction_theta_full 0.979
_diffrn_measured_fraction_theta_max 0.956
_diffrn_measurement_device_type  'Rigaku Spider'
_diffrn_measurement_method       \w-scans
_diffrn_radiation_monochromator  'Rigaku VariMax-HF Confocal Optical System'
_diffrn_radiation_source         'Rigaku MM007 rotating anode'
_diffrn_radiation_wavelength     1.54178
_diffrn_reflns_av_R_equivalents  0.0575
_diffrn_reflns_av_unetI/netI     0.0819
_diffrn_reflns_Laue_measured_fraction_full 0.979
_diffrn_reflns_Laue_measured_fraction_max 0.956
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       31
_diffrn_reflns_limit_k_min       -30
_diffrn_reflns_limit_l_max       11
_diffrn_reflns_limit_l_min       -11
_diffrn_reflns_number            17505
_diffrn_reflns_point_group_measured_fraction_full 0.981
_diffrn_reflns_point_group_measured_fraction_max 0.958
_diffrn_reflns_theta_full        67.679
_diffrn_reflns_theta_max         71.986
_diffrn_reflns_theta_min         6.617
_exptl_absorpt_coefficient_mu    46.724
_exptl_absorpt_correction_T_max  1.0
_exptl_absorpt_correction_T_min  0.27
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details   '(ABSCOR; Higashi, 1995)'
_exptl_crystal_colour            'pale yellow'
_exptl_crystal_density_diffrn    2.653
_exptl_crystal_description       rod
_exptl_crystal_F_000             1238
_exptl_crystal_size_max          0.454
_exptl_crystal_size_mid          0.050
_exptl_crystal_size_min          0.050
_refine_diff_density_max         4.656
_refine_diff_density_min         -6.289
_refine_diff_density_rms         0.520
_refine_ls_abs_structure_details
;
 Refined as a perfect inversion twin.
ISOR restraint used for all C and N atoms.
Certain C and N atoms refined isotropically
with fixed thermal parameters.
All aromitc rings were made planar with a FLAT
command.
Pseudo-symmetry exists and P2(1)/c is an
alternative space group but the current
choice of space group produced superior
statistics.
;
_refine_ls_abs_structure_Flack   0.5
_refine_ls_extinction_coef       .
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.159
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     355
_refine_ls_number_reflns         6203
_refine_ls_number_restraints     211
_refine_ls_restrained_S_all      1.140
_refine_ls_R_factor_all          0.0830
_refine_ls_R_factor_gt           0.0636
_refine_ls_shift/su_max          0.053
_refine_ls_shift/su_mean         0.001
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
;
 w=1/[\s^2^(Fo^2^)+(0.0001P)^2^+111.1734P]
 where P=(Fo^2^+2Fc^2^)/3
;
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1419
_refine_ls_wR_factor_ref         0.1815
_reflns_Friedel_coverage         0.957
_reflns_Friedel_fraction_full    0.983
_reflns_Friedel_fraction_max     0.959
_reflns_number_gt                5009
_reflns_number_total             6203
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            JSSC-2015-221-433.cif
_cod_data_source_block           shelx
_cod_original_sg_symbol_Hall     P21
_cod_original_sg_symbol_H-M      P21
_cod_database_code               1562165
_shelx_estimated_absorpt_t_min   0.017
_shelx_estimated_absorpt_t_max   0.203
_shelxl_version_number           2013-2
_shelx_res_checksum              74931
_shelx_hkl_checksum              79996