Polymorphism of pure p-tert-butylcalix[4]arene: subtle thermally-induced modifications.
Atwood, Jerry L; Barbour, Leonard J; Lloyd, Gareth O; Thallapally, Praveen K; Chemical communications (Cambridge, England)  (2004) 922–923; doi:10.1039/b402452b

data_7102600
_publ_section_title
;
 Polymorphism of pure p-tert-butylcalix[4]arene: subtle
 thermally-induced modifications.
;
_journal_issue                   8
_journal_name_full               'Chemical communications (Cambridge, England)'
_journal_page_first              922
_journal_page_last               923
_journal_paper_doi               10.1039/b402452b
_journal_year                    2004
_chemical_formula_sum            'C44 H56 O4'
_chemical_formula_weight         648.89
_chemical_name_common            TBC4@130Degrees
_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                 90.13(3)
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   12.804(3)
_cell_length_b                   26.742(5)
_cell_length_c                   12.799(3)
_cell_measurement_temperature    403(2)
_cell_volume                     4382.5(15)
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      403(2)
_diffrn_measured_fraction_theta_full 0.961
_diffrn_measured_fraction_theta_max 0.961
_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  0.3464
_diffrn_reflns_av_sigmaI/netI    0.5099
_diffrn_reflns_limit_h_max       13
_diffrn_reflns_limit_h_min       -13
_diffrn_reflns_limit_k_max       21
_diffrn_reflns_limit_k_min       -26
_diffrn_reflns_limit_l_max       5
_diffrn_reflns_limit_l_min       -13
_diffrn_reflns_number            7552
_diffrn_reflns_theta_full        22.02
_diffrn_reflns_theta_max         22.02
_diffrn_reflns_theta_min         1.52
_exptl_absorpt_coefficient_mu    0.061
_exptl_absorpt_correction_T_max  0.9909
_exptl_absorpt_correction_T_min  0.9759
_exptl_absorpt_correction_type   'empirical - using SADABS'
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    0.983
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       prism
_exptl_crystal_F_000             1408
_exptl_crystal_size_max          0.40
_exptl_crystal_size_mid          0.30
_exptl_crystal_size_min          0.15
_refine_diff_density_max         0.542
_refine_diff_density_min         -0.372
_refine_diff_density_rms         0.127
_refine_ls_extinction_coef       0.014(3)
_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   1.090
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     72
_refine_ls_number_reflns         5188
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.090
_refine_ls_R_factor_all          0.4833
_refine_ls_R_factor_gt           0.2373
_refine_ls_shift/su_max          0.106
_refine_ls_shift/su_mean         0.011
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.2000P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.5396
_refine_ls_wR_factor_ref         0.6251
_reflns_number_gt                845
_reflns_number_total             5188
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            b402452b.txt
_cod_data_source_block           compound_1
_cod_original_sg_symbol_H-M      P21/n
_cod_database_code               7102600