data_4020935 loop_ _publ_author_name 'Daniel B. Werz' 'Rolf Gleiter' 'Frank Rominger' _publ_section_title ; Cyclic Tetra- and Hexaynes Containing 1,4-Donor-Substituted Butadiyne Units: Synthesis and Supramolecular Organization ; _journal_name_full 'Journal of Organic Chemistry' _journal_volume 69 _journal_page_first 2945 _journal_page_last 2952 _journal_year 2004 _chemical_formula_sum 'C18 H20 Se4' _chemical_formula_weight 552.18 _symmetry_cell_setting Monoclinic _symmetry_space_group_name_H-M 'P 21/c' loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x, y+1/2, -z+1/2' '-x, -y, -z' 'x, -y-1/2, z-1/2' _cell_length_a 4.5218(2) _cell_length_b 17.4976(7) _cell_length_c 13.9348(6) _cell_angle_alpha 90.00 _cell_angle_beta 91.8960(10) _cell_angle_gamma 90.00 _cell_volume 1101.93(8) _cell_formula_units_Z 2 _cell_measurement_temperature 200(2) _exptl_crystal_density_diffrn 1.664 _diffrn_ambient_temperature 200(2) loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_adp_type _atom_site_occupancy _atom_site_symmetry_multiplicity _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group Se1 Se 0.77536(7) 0.464665(18) 0.89182(2) 0.03113(11) Uani 1 1 d . . . Se2 Se 0.71270(8) 0.813987(18) 0.48270(2) 0.03612(12) Uani 1 1 d . . . C1 C 0.5159(8) 0.69459(19) 0.3363(3) 0.0372(8) Uani 1 1 d . . . C2 C 0.5969(8) 0.74053(19) 0.3963(2) 0.0359(8) Uani 1 1 d . . . C4 C 0.9513(8) 0.74902(19) 0.5696(2) 0.0356(8) Uani 1 1 d . . . H4A H 1.0981 0.7211 0.5317 0.043 Uiso 1 1 calc R . . H4B H 1.0617 0.7820 0.6161 0.043 Uiso 1 1 calc R . . C5 C 0.7721(7) 0.69170(18) 0.6244(2) 0.0312(8) Uani 1 1 d . . . H5A H 0.6664 0.6573 0.5784 0.037 Uiso 1 1 calc R . . H5B H 0.6224 0.7191 0.6616 0.037 Uiso 1 1 calc R . . C6 C 0.9677(7) 0.64449(18) 0.6922(2) 0.0318(7) Uani 1 1 d . . . H6A H 1.0707 0.6791 0.7386 0.038 Uiso 1 1 calc R . . H6B H 1.1202 0.6183 0.6548 0.038 Uiso 1 1 calc R . . C7 C 0.7951(7) 0.58472(18) 0.7476(2) 0.0295(7) Uani 1 1 d . . . H7A H 0.6445 0.6108 0.7858 0.035 Uiso 1 1 calc R . . H7B H 0.6902 0.5504 0.7014 0.035 Uiso 1 1 calc R . . C8 C 0.9943(7) 0.53729(17) 0.8142(2) 0.0301(7) Uani 1 1 d . . . H8A H 1.1089 0.5720 0.8575 0.036 Uiso 1 1 calc R . . H8B H 1.1368 0.5088 0.7753 0.036 Uiso 1 1 calc R . . C10 C 0.6546(8) 0.40043(18) 0.7945(2) 0.0341(8) Uani 1 1 d . . . C11 C 0.5733(8) 0.3564(2) 0.7333(2) 0.0366(8) Uani 1 1 d . . . C20 C 0.3492(19) 0.5026(5) 0.5070(6) 0.129(3) Uani 1 1 d . . . C21 C -0.030(8) 0.5347(7) 0.4580(9) 0.288(10) Uani 1 1 d . . . loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_23 _atom_site_aniso_U_13 _atom_site_aniso_U_12 Se1 0.0419(2) 0.02338(18) 0.02772(18) 0.00284(13) -0.00489(14) -0.00134(14) Se2 0.0547(3) 0.02117(18) 0.03199(19) 0.00335(13) -0.00648(16) -0.00665(15) C1 0.047(2) 0.0273(18) 0.0365(19) 0.0045(15) -0.0047(17) -0.0045(16) C2 0.043(2) 0.0289(18) 0.0355(19) 0.0055(15) -0.0018(15) -0.0089(16) C4 0.038(2) 0.0299(19) 0.0389(19) 0.0072(15) -0.0063(15) -0.0083(15) C5 0.0317(18) 0.0264(17) 0.0354(18) 0.0041(13) -0.0006(15) -0.0056(14) C6 0.0283(17) 0.0269(17) 0.0398(19) 0.0064(14) -0.0042(14) -0.0053(14) C7 0.0312(18) 0.0245(17) 0.0325(18) 0.0042(14) -0.0044(14) -0.0008(14) C8 0.0277(17) 0.0243(17) 0.0382(18) 0.0019(14) -0.0019(14) -0.0022(14) C10 0.044(2) 0.0230(17) 0.0352(18) 0.0038(14) -0.0061(15) 0.0005(15) C11 0.045(2) 0.031(2) 0.0331(18) 0.0078(15) -0.0066(16) -0.0039(16) C20 0.189(10) 0.099(5) 0.100(5) -0.077(4) 0.005(9) 0.000(9) C21 0.56(3) 0.148(12) 0.163(12) -0.053(8) 0.09(2) 0.073(18) loop_ _geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 _geom_bond_distance _geom_bond_site_symmetry_2 _geom_bond_publ_flag Se1 C10 1.831(3) . ? Se1 C8 1.959(3) . ? Se2 C2 1.826(3) . ? Se2 C4 1.958(3) . ? C1 C2 1.207(5) . ? C1 C11 1.369(5) 3_666 ? C4 C5 1.512(4) . ? C5 C6 1.518(4) . ? C6 C7 1.529(4) . ? C7 C8 1.519(4) . ? C10 C11 1.197(5) . ? C11 C1 1.369(5) 3_666 ? C20 C20 1.387(17) 3_666 ? C20 C21 1.67(3) 3_566 ? C20 C21 1.91(3) . ? C21 C20 1.67(3) 3_566 ? C21 C21 1.70(2) 3_566 ?