Single-crystal X-ray geometries and electron density distributions of cyclopropane, bicyclopropyl and vinylcyclopropane. I. Data collection, structure determination and conventional refinements

Crystal structures of cyclopropane (CP) C3H 6, bicyclopropyl (BCP) C6HI0 and vinylcyclopropane (VCP) C5H s have been determined by accurate single-crystal X-ray measurements at T,~ 100 K. In addition to the conventional full-angle refinements [(sin0)/2<1.15 A -~ for CP and < 1.22 A -I for BCP and VCP], high-order refinements [(sin0)/2 > 0.60 A -1 for CP, > 0.80A -I for BCP and > 0.70A -l for VCP] have been performed to obtain accurate parameters for C atoms. C3H6: CP molecules in the crystal approximate the D3h symmetry of the free CP molecule; M r= 42.08, orthorhombic, Cmc2~, a = 7.971 (3), b=6.575(3), c=5.844(2)A, V=306.3(2)A 3, Z =4, Dx=0.913Mgm -3, 2(MoK~)=0.71069A, # = 0.540 cm -l, F(000) = 96, T= 94 K, R(F) = 0.0328 and Rw(F)= 0.0280 for the full-angle refinement on 915 observed independent reflections. C6HI0: The molecules in the crystal have the trans-bisected conformation; Mr=82"15, orthorhombic, Cmca, a=8.8528(7), b=5.0911(3), c=11.7294(13) A, V=528.65 (8) A 3, Z = 4, D x = 1.033 Mg m -3, 2(Mo K~)=0.71069 A, /t=0.616cm -1, F(000)= 184, T=100 K, R(F) = 0.0389 and Rw(F) = 0.0414 for the full-angle refinement on 1817 observed independent reflections. CsHs: The molecules in the crystal deviate slightly from the trans-bisected conformation; M r = 68.12, monoclinic, P2 l, a=4.8792 (9), b= 7.1617(11), c=6.9230(11)A, fl=105.068(13) °, V = 233.60 (7) A 3, z = 2, D x = 0.968 Mg m -3, 2(Mo K~) = 0.71069 A, # = 0.579 cm -j, F(000) = 76, T= 94 K, R(F) = 0.0323 and Rw(F) = 0.0395 for the full-angle refinement on 3480 observed independent reflections.