Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refined as a 2-component inversion twin.1. Twinned data refinement Scales: 0.522 (18) 0.478 (18) 2. Fixed Uiso At 1.2 times of: All C(H) groups At 1.5 times of: All C(H,H,H) groups 3. Restrained distances H18-N18 0.86 with sigma of 0.02 H14-N14 0.86 with sigma of 0.02 4.a Aromatic/amide H refined with riding coordinates: C35(H35), C23(H23), C27(H27), C26(H26), C49(H49), C31(H31), C28(H28), C61(H61), C54(H54), C36(H36), C60(H60), C50(H50), C22(H22), C40(H40), C53(H53), C37(H37), C42(H42), C47(H47), C64(H64), C63(H63), C46(H46), C43(H43), C39(H39), C32(H32), C56(H56), C57(H57) 4.b Idealised Me refined as rotating group: C52(H52A,H52B,H52C), C44(H44A,H44B,H44C), C58(H58A,H58B,H58C), C66(H66A,H66B, H66C), C51(H51A,H51B,H51C), C45(H45A,H45B,H45C), C65(H65A,H65B,H65C), C59(H59A, H59B,H59C)