Table 1:

Selected bond lengths (Å) and angles (°) for compounds 1, 2 and 4. Where two sets of values are given, two molecules were found in the asymmetric unit.

Metric	1	2	4
Re(1)-N(2) (amine) (Å)	2.207(7)	2.197(5)	2.198(5)
Re(2)-N(4)	2.199(7)	-	2.191(5)
Re(1)-N(1) (ring) (Å)	2.195(8)	2.179(4)	2.180(5)
Re(1)-N(1)	2.174(8)	-	2.186(5)
Re(1)-C(1) (Å)	1.889(9)	1.915(6)	1.915(6)
Re(1)-C(2)	1.931(11)	1.922(6)	1.918(7)
Re(1)-C(3)	1.923(9)	1.911(6)	1.898(7)
Re(2)-C(13) (Å)	1.917(9)	-	1.891(7)
Re(2)-C(14)	1.931(11)	-	1.916(7)
Re(2)-C(15)	1.893(9)	-	1.915(7)
C(1)-O(1) (Å)	1.162(11)	1.129(6)	1.152(7)
C(2)-O(2)	1.142(13)	1.154(7)	1.151(8)
C(3)-O(3)	1.153(12)	1.153(7)	1.145(8)
C(13)-O(4)	1.159(11)	-	1.156(8)
C(14)-O(5)	1.142(13)	-	1.152(7)
C(15)-O(6)	1.163(11)	-	1.155(8)
N(1)-Re(1)-N(2) (°)	76.5(3)	76.63(16)	76.63(19)
N(3)-Re(2)-N(4)	76.6(3)	-	76.82(19)