Fig. 1. X-ray diffraction structures of 3a (left) and 3b (right). Hydrogen atoms and co-crystallized solvent molecules are omitted for clarity. Selected bond lengths [Å] and angles [°]: 3a: B1–C1 1.681(3), B1–C2 1.622(2), B1–Cl1 1.938(2), B1–Cl2 1.889(2), C1–N1 1.376(2), C1–N2 1.352(2), C1–B1–C2 118.9(1), Cl1–B1–Cl2 103.71(9), N1–C1–N2 117.0(2); 3b: B1–C1 1.676(5), B1–C2 1.623(5), B1–Cl1 1.910(4), B1–Cl2 1.920(4), C1–N1 1.364(5), C1–N2 1.365(4), C1–B1–C2 113.5(3), Cl1–B1–Cl2 101.4(2), N1–B1–N2 116.6(3).
