Organometallic single-molecule electronics: tuning electron transport through X(diphosphine)2FeC4Fe(diphosphine)2X building blocks by varying the Fe-X-Au anchoring scheme from coordinative to covalent.
Lissel, Franziska; Schwarz, Florian; Blacque, Olivier; Riel, Heike; Lörtscher, Emanuel; Venkatesan, Koushik; Berke, Heinz; Journal of the American Chemical Society 136 (2014) 14560–14569; doi:10.1021/ja507672g

data_4129265
_publ_section_title
;
 Organometallic single-molecule electronics: tuning electron transport
 through X(diphosphine)2FeC4Fe(diphosphine)2X building blocks by varying
 the Fe-X-Au anchoring scheme from coordinative to covalent.
;
_journal_issue                   41
_journal_name_full               'Journal of the American Chemical Society'
_journal_page_first              14560
_journal_page_last               14569
_journal_paper_doi               10.1021/ja507672g
_journal_volume                  136
_journal_year                    2014
_chemical_formula_moiety         'C48 H98 Fe2 P8'
_chemical_formula_sum            'C48 H98 Fe2 P8'
_chemical_formula_weight         1034.72
_chemical_name_systematic
(\m^2^-Buta-1,3-diyne-1,4-diyl){tetrakis[ethane-1,2-diylbis(diethylphosphane-\k<i>P</i>)]}diethynyldiiron
_space_group_crystal_system      monoclinic
_space_group_IT_number           15
_space_group_name_Hall           '-C 2yc'
_space_group_name_H-M_alt        'C 1 2/c 1'
_atom_sites_solution_hydrogens   mixed
_audit_creation_date             2013-11-20
_audit_creation_method
;
Olex2 1.2
(compiled 2013.11.15 svn.r2834 for OlexSys, GUI svn.r4709)
;
_cell_angle_alpha                90
_cell_angle_beta                 116.945(2)
_cell_angle_gamma                90
_cell_formula_units_Z            4
_cell_length_a                   29.5938(6)
_cell_length_b                   10.0002(1)
_cell_length_c                   21.1040(4)
_cell_measurement_reflns_used    24890
_cell_measurement_temperature    183(2)
_cell_measurement_theta_max      32.7
_cell_measurement_theta_min      2.6
_cell_volume                     5567.59(19)
_computing_cell_refinement
;
CrysAlisPro, Version 1.171.33.55 (Oxford Diffraction Ltd., 2010)
;
_computing_data_collection
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CrysAlisPro, Version 1.171.33.55 (Oxford Diffraction Ltd., 2010)
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CrysAlisPro, Version 1.171.33.55 (Oxford Diffraction Ltd., 2010)
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_computing_molecular_graphics    'Mercury (Macrae et al., 2006)'
_computing_publication_material
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Mercury (Macrae et al., 2006)
Olex2 (Dolomanov et al., 2009)
PLATON for Windows (Spek, 2003)
PublCIF (Westrip, 2010)
ShelXL2013 (Sheldrick, 2008) 
WinGX (Farrugia, 1999)
;
_computing_structure_refinement  'ShelXL2013 (Sheldrick, 2008)'
_computing_structure_solution    'ShelXS97 (Sheldrick, 2008)'
_diffrn_ambient_temperature      183(2)
_diffrn_detector_area_resol_mean 10.4498
_diffrn_measured_fraction_theta_full 0.999
_diffrn_measured_fraction_theta_max 0.999
_diffrn_measurement_device_type  'Xcalibur, Ruby'
_diffrn_measurement_method       '\w scans'
_diffrn_orient_matrix_UB_11      0.0215214000
_diffrn_orient_matrix_UB_12      -0.0141948000
_diffrn_orient_matrix_UB_13      -0.0053088000
_diffrn_orient_matrix_UB_21      -0.0145559000
_diffrn_orient_matrix_UB_22      0.0114945000
_diffrn_orient_matrix_UB_23      -0.0369791000
_diffrn_orient_matrix_UB_31      0.0068900000
_diffrn_orient_matrix_UB_32      0.0685475000
_diffrn_orient_matrix_UB_33      0.0051040000
_diffrn_radiation_monochromator  graphite
_diffrn_radiation_type           MoK\a
_diffrn_radiation_wavelength     0.71073
_diffrn_reflns_av_R_equivalents  0.0261
_diffrn_reflns_av_unetI/netI     0.0186
_diffrn_reflns_limit_h_max       39
_diffrn_reflns_limit_h_min       -39
_diffrn_reflns_limit_k_max       13
_diffrn_reflns_limit_k_min       -13
_diffrn_reflns_limit_l_max       28
_diffrn_reflns_limit_l_min       -28
_diffrn_reflns_number            44136
_diffrn_reflns_theta_full        25.242
_diffrn_reflns_theta_max         28.282
_diffrn_reflns_theta_min         2.583
_diffrn_source                   'Enhance (Mo) X-ray Source'
_exptl_absorpt_coefficient_mu    0.781
_exptl_absorpt_correction_T_max  0.931
_exptl_absorpt_correction_T_min  0.744
_exptl_absorpt_correction_type   analytical
_exptl_absorpt_process_details
;
CrysAlisPro, Oxford Diffraction Ltd.,
Version 1.171.33.55 (release 05-01-2010 CrysAlis171 .NET)
(compiled Jan  5 2010,16:28:46)
Analytical numeric absorption correction using a multifaceted crystal
model based on expressions derived by R.C. Clark & J.S. Reid.
(Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897)
;
_exptl_crystal_colour            yellow
_exptl_crystal_density_diffrn    1.234
_exptl_crystal_description       tablet
_exptl_crystal_F_000             2232
_exptl_crystal_size_max          0.55
_exptl_crystal_size_mid          0.28
_exptl_crystal_size_min          0.11
_refine_diff_density_max         0.846
_refine_diff_density_min         -0.552
_refine_diff_density_rms         0.085
_refine_ls_extinction_method     none
_refine_ls_goodness_of_fit_ref   1.055
_refine_ls_hydrogen_treatment    mixed
_refine_ls_matrix_type           full
_refine_ls_number_parameters     314
_refine_ls_number_reflns         6905
_refine_ls_number_restraints     82
_refine_ls_restrained_S_all      1.059
_refine_ls_R_factor_all          0.0544
_refine_ls_R_factor_gt           0.0466
_refine_ls_shift/su_max          0.002
_refine_ls_shift/su_mean         0.000
_refine_ls_structure_factor_coef Fsqd
_refine_ls_weighting_details
'w=1/[\s^2^(Fo^2^)+(0.0885P)^2^+8.2438P] where P=(Fo^2^+2Fc^2^)/3'
_refine_ls_weighting_scheme      calc
_refine_ls_wR_factor_gt          0.1417
_refine_ls_wR_factor_ref         0.1459
_reflns_number_gt                5800
_reflns_number_total             6905
_reflns_threshold_expression     'I > 2\s(I)'
_cod_data_source_file            ja507672g_si_002.cif
_cod_data_source_block           4
_cod_database_code               4129265
_shelxl_version_number           2013-4
_olex2_refinement_description
;
1. Fixed Uiso
 At 1.2 times of:
  All C(H,H) groups
 At 1.5 times of:
  All C(H,H,H) groups
2. Restrained distances
 C9A-C10A = C9B-C10B = C23A-C24A = C23B-C24B
 1.52 with sigma of 0.005
 P1-C9A \\sim P1-C9B \\sim P4-C23A \\sim P4-C23B
 with sigma of 0.005
3. Uiso/Uaniso restraints and constraints
C23A \\sim C23B \\sim C24A \\sim C24B: within 3A with sigma of 0.005 and sigma
for terminal atoms of 0.01
C9A \\sim C9B \\sim C10A \\sim C10B: within 3A with sigma of 0.005 and sigma
for terminal atoms of 0.01
4. Others
 Sof(C9B)=Sof(H9BA)=Sof(H9BB)=Sof(C10B)=Sof(H10D)=Sof(H10E)=Sof(H10F)=1-FVAR(1)
 Sof(C9A)=Sof(H9AA)=Sof(H9AB)=Sof(C10A)=Sof(H10A)=Sof(H10B)=Sof(H10C)=FVAR(1)
 Sof(C23B)=Sof(H23C)=Sof(H23D)=Sof(C24B)=Sof(H24D)=Sof(H24E)=Sof(H24F)=1-FVAR(2)
 Sof(C23A)=Sof(H23A)=Sof(H23B)=Sof(C24A)=Sof(H24A)=Sof(H24B)=Sof(H24C)=FVAR(2)
5.a Secondary CH2 refined with riding coordinates:
 C5(H5A,H5B), C6(H6A,H6B), C7(H7A,H7B), C9A(H9AA,H9AB), C9B(H9BA,H9BB),
 C11(H11A,H11B), C13(H13A,H13B), C15(H15A,H15B), C16(H16A,H16B), C17(H17A,H17B),
  C19(H19A,H19B), C21(H21A,H21B), C23A(H23A,H23B), C23B(H23C,H23D)
5.b Idealised Me refined as rotating group:
 C8(H8A,H8B,H8C), C10A(H10A,H10B,H10C), C10B(H10D,H10E,H10F), C12(H12A,H12B,
 H12C), C14(H14A,H14B,H14C), C18(H18A,H18B,H18C), C20(H20A,H20B,H20C), C22(H22A,
 H22B,H22C), C24A(H24A,H24B,H24C), C24B(H24D,H24E,H24F)
;