The molecular structure of 10 as determined by a single crystal X-ray diffraction study. The hydrogen atoms were omitted for clarity; the thermal ellipsoids were set at the 50 % probability level. Selected bond lengths are given in Å. Selected bond angles (°): N(1)-Nb(1)-N(2) 112.80(13), N(1)-Nb(1)-N(3) 103.75(12), N(2)-Nb(1)-N(3) 95.85(12), N(1)-Nb(1)-N(5) 96.98(12), N(2)-Nb(1)-N(5) 83.94(11), N(3)-Nb(1)-N(5) 157.48(10), N(1)-Nb(1)-N(4) 105.38(11), N(2)-Nb(1)-N(4) 140.94(12), N(3)-Nb(1)-N(4) 82.52(10), N(5)-Nb(1)-N(4) 83.60(10), C(1)-N(1)-Nb(1) 165.3(3), C(5)-N(2)-Nb(1) 166.7(3).