The crystal structures of methyl prop-2-ynoate, dimethyl fumarate and their protonated species.
Hollenwäger, Dirk; Bockmair, Valentin; Kornath, Andreas J.; Acta crystallographica. Section C, Structural chemistry 81 (2025) –; doi:10.1107/S2053229624011653

data_2312731
_publ_section_title
;
 The crystal structures of methyl prop-2-ynoate, dimethyl fumarate and
 their protonated species.
;
_journal_coeditor_code           OJ3025
_journal_issue                   1
_journal_name_full
'Acta crystallographica. Section C, Structural chemistry'
_journal_paper_doi               10.1107/S2053229624011653
_journal_volume                  81
_journal_year                    2025
_chemical_formula_iupac          'C4 H5 O2 +, As F6 -'
_chemical_formula_moiety         'C4 H5 O2 +, As F6 -'
_chemical_formula_sum            'C4 H5 As F6 O2'
_chemical_formula_weight         274.00
_chemical_name_systematic
;
(1-Methoxyprop-2-yn-1-ylidene)oxidanium hexafluoroarsenate
;
_space_group_crystal_system      monoclinic
_space_group_IT_number           14
_space_group_name_Hall           '-P 2yn'
_space_group_name_H-M_alt        'P 1 21/n 1'
_atom_sites_solution_hydrogens   mixed
_atom_sites_solution_primary     direct
_atom_sites_solution_secondary   difmap
_audit_creation_method           SHELXL-2019/3
_cell_angle_alpha                90
_cell_angle_beta                 91.664(7)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   6.9609(5)
_cell_length_b                   8.9319(7)
_cell_length_c                   13.7189(9)
_cell_measurement_reflns_used    1298
_cell_measurement_temperature    111(2)
_cell_measurement_theta_max      31.4470
_cell_measurement_theta_min      2.2840
_cell_volume                     852.60(11)
_computing_cell_refinement
;
CrysAlis PRO (Rigaku OD, 2020)
;
_computing_data_collection
;
CrysAlis PRO (Rigaku OD, 2020)
;
_computing_data_reduction
;
CrysAlis PRO (Rigaku OD, 2020)
;
_computing_molecular_graphics
;
ORTEP-3 for Windows (Farrugia, 2012)
;
_computing_publication_material
;
PLATON (Spek, 2020)
;
_computing_structure_refinement
;
SHELXL2018 (Sheldrick, 2015<i>b</i>)
;
_computing_structure_solution
;
SHELXT (Sheldrick, 2015<i>a</i>)
;
_diffrn_ambient_temperature      111(2)
_diffrn_detector                 'CCD plate'
_diffrn_detector_area_resol_mean 15.9809
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 1.000
_diffrn_measurement_device       'CCD camera on \k-goniostat'
_diffrn_measurement_device_type  'Rigaku Xcalibur Sapphire3'
_diffrn_measurement_method       '\w scans'
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_source         'Enhance (Mo) X-ray Source'
_diffrn_radiation_type           'Mo K\a'
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0288
_diffrn_reflns_av_unetI/netI     0.0470
_diffrn_reflns_limit_h_max       9
_diffrn_reflns_limit_h_min       -6
_diffrn_reflns_limit_k_max       12
_diffrn_reflns_limit_k_min       -9
_diffrn_reflns_limit_l_max       18
_diffrn_reflns_limit_l_min       -18
_diffrn_reflns_number            4205
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         29.127
_diffrn_reflns_theta_min         2.722
_diffrn_source_current           40
_diffrn_source_voltage           50
_exptl_absorpt_coefficient_mu    4.055
_exptl_absorpt_correction_T_max  1.00000
_exptl_absorpt_correction_T_min  0.58179
_exptl_absorpt_correction_type   multi-scan
_exptl_absorpt_process_details
;
(CrysAlis PRO; Rigaku OD, 2020)
;
_exptl_crystal_colour            colorless
_exptl_crystal_density_diffrn    2.135
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needle
_exptl_crystal_F_000             528
_exptl_crystal_size_max          0.900
_exptl_crystal_size_mid          0.206
_exptl_crystal_size_min          0.146
_refine_diff_density_max         0.872
_refine_diff_density_min         -0.923
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.051
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     123
_refine_ls_number_reflns         2303
_refine_ls_number_restraints     0
_refine_ls_restrained_S_all      1.051
_refine_ls_R_factor_all          0.0501
_refine_ls_R_factor_gt           0.0388
_refine_ls_shift/su_max          0.001
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0444P)^2^] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.0895
_refine_ls_wR_factor_ref         0.0986
_reflns_number_gt                1900
_reflns_number_total             2303
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            oj3025.cif
_cod_data_source_block           III
_cod_original_sg_symbol_H-M      'P 21/n'
_cod_database_code               2312731
_shelx_estimated_absorpt_t_min   0.121
_shelx_estimated_absorpt_t_max   0.589
_shelx_hkl_checksum              32586
_shelx_res_checksum              53313