Squaramide-based reagent for selective chromogenic sensing of Cu(II) through a zwitterion radical.
Sanna, Elena; Martínez, Luis; Rotger, Carmen; Blasco, Salvador; González, Jorge; García-España, Enrique; Costa, Antoni; Organic letters 12 (2010) 3840–3843; doi:10.1021/ol101514y

data_1503140
_publ_section_title
;
 Squaramide-based reagent for selective chromogenic sensing of Cu(II)
 through a zwitterion radical.
;
_journal_issue                   17
_journal_name_full               'Organic letters'
_journal_page_first              3840
_journal_page_last               3843
_journal_paper_doi               10.1021/ol101514y
_journal_volume                  12
_journal_year                    2010
_chemical_formula_moiety         'C12 H12 N2 O3, 2.36(H2O)'
_chemical_formula_sum            'C12 H16.72 N2 O5.36'
_chemical_formula_weight         265.24
_chemical_name_common            'dimethylphenyl squaramide'
_chemical_name_systematic
; 
 3-(4-(N,N-dimethylamino)phenylamino)-4-hydroxycyclobut-3-ene-1,2-dione 
;
_space_group_IT_number           62
_symmetry_cell_setting           orthorhombic
_symmetry_space_group_name_Hall  '-P 2ac 2n'
_symmetry_space_group_name_H-M   'P n m a'
_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                 90.00
_cell_angle_gamma                90.00
_cell_formula_units_Z            4
_cell_length_a                   19.0772(7)
_cell_length_b                   6.9067(3)
_cell_length_c                   9.6850(3)
_cell_measurement_reflns_used    5509
_cell_measurement_temperature    293(2)
_cell_measurement_theta_max      27.485
_cell_measurement_theta_min      0.998
_cell_volume                     1276.10(8)
_computing_cell_refinement       'HKL Scalepack (Otwinowski & Minor 1997)'
_computing_data_collection       'Collect (Bruker AXS BV, 1997-2004)'
_computing_data_reduction
'HKL Denzo and Scalepack (Otwinowski & Minor 1997)'
_computing_structure_refinement  'SHELXL-97 (Sheldrick, 1997)'
_computing_structure_solution    'SHELXS-97 (Sheldrick, 1990)'
_diffrn_ambient_temperature      293(2)
_diffrn_detector_area_resol_mean 9
_diffrn_measured_fraction_theta_full 0.985
_diffrn_measured_fraction_theta_max 0.985
_diffrn_measurement_device       '95mm CCD camera on \k-goniostat'
_diffrn_measurement_device_type  KappaCCD
_diffrn_measurement_method       CCD
_diffrn_radiation_monochromator  'horizonally mounted graphite crystal'
_diffrn_radiation_source         'fine-focus sealed tube'
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.1016
_diffrn_reflns_av_sigmaI/netI    0.0562
_diffrn_reflns_limit_h_max       24
_diffrn_reflns_limit_h_min       -24
_diffrn_reflns_limit_k_max       8
_diffrn_reflns_limit_k_min       -8
_diffrn_reflns_limit_l_max       12
_diffrn_reflns_limit_l_min       -12
_diffrn_reflns_number            10260
_diffrn_reflns_theta_full        27.47
_diffrn_reflns_theta_max         27.47
_diffrn_reflns_theta_min         2.14
_exptl_absorpt_coefficient_mu    0.109
_exptl_absorpt_correction_type   none
_exptl_crystal_colour            'pale yellow'
_exptl_crystal_density_diffrn    1.381
_exptl_crystal_density_method    'not measured'
_exptl_crystal_description       needles
_exptl_crystal_F_000             556
_exptl_crystal_size_max          0.34
_exptl_crystal_size_mid          0.10
_exptl_crystal_size_min          0.07
_refine_diff_density_max         0.002
_refine_diff_density_min         -0.001
_refine_diff_density_rms         0.000
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.179
_refine_ls_hydrogen_treatment    constr
_refine_ls_matrix_type           full
_refine_ls_number_parameters     122
_refine_ls_number_reflns         1568
_refine_ls_number_restraints     12
_refine_ls_restrained_S_all      1.188
_refine_ls_R_factor_all          0.1343
_refine_ls_R_factor_gt           0.0622
_refine_ls_shift/su_max          0.018
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'calc w=1/[\s^2^(Fo^2^)+(0.1001P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1699
_refine_ls_wR_factor_ref         0.2044
_reflns_number_gt                819
_reflns_number_total             1568
_reflns_threshold_expression     >2sigma(I)
_cod_data_source_file            ol101514y_si_003.cif
_cod_data_source_block           squaramide
_cod_database_code               1503140