XRD structures of 8 (left) and 10 (right). Ellipsoids shown at 50% probability. Selected bond distances (Å) and angles (°): 8 (average for two molecules in the asymmetric unit cell), Fe1-B1 = 2.491(1), Fe1-C37 = 2.103(1), Fe1-C38 = 2.113(1), C37-C38 = 1.397(2), Σ(P-Fe-P) = 338.76(3); 10 (average for two molecules in the asymmetric unit cell), Fe1-B1 = 2.761(2), Fe1-C37 = 1.918(2) C37-C38 = 1.169(3), Σ(P-Fe-P) = 345.07(2).