Table 1 the computed parameters of complex in S₀ & T₁ states at the B3LYP/6–311 +  + G(d, p)/LANL2DZ level. Angles measured (degrees) & distances (angstroms)

Bond length (Å)

 Re-Cl8

2.574

2.551

2.513

 Re-C2

1.915

1.909

1.933

 Re-C3

1.907

1.924

1.934

 Re-C4

2.058

1.925

1.970

 Re-N26

2.163

2.172

2.156

 Re-N27

2.171

2.167

2.086

Bond angles (^o)

 N26-Re-N27

74.70

75.32

77.27

 C2-Re-C4

95.90

91.79

89.91

 C2-Re-C3

90.30

91.79

92.21

 C2-Re-N26

90.70

93.88

93.27

 C2-Re-N27

86.00

93.60

91.45

 C3-Re-N27

97.50

75.32

77.27

 C4-Re-N26

97.80

91.79

89.91

 C4-Re-Cl8

–

91.79

92.21