RWLC-6 in which the ΔE 1 and k 1 values are significantly reduced, and the value of
k 0 is increased by a factor of ~2. The short lifetime population associated with
RWLC-6 is likely one in which the barrier to access the
3
LF state is sufficiently high
as to preclude occupation, and the ΔE 1 represents the barrier to access a fourth
3 MLCT (above the emitting
3 MLCT manifold) instead. The increase in k 0 is
consistent with RuBpy cations associated with the short lifetime population being
in close proximity and undergoing self-quenching (Fig. 22).
The corresponding long lifetime population exhibits a ΔE 1 value in between what
is observed for RuBpy in solution and that of the lowest singlet in character MLCT
states observed in RWLC-1 and RWLC-2. The fact that the lifetime is greatly
0
1
2
3
4
5
6
0.0
0.2
0.4
0.6
0.8
1.0
Normalized Emission Intensity
Time (µs)
RWLC-6
RuBpy in EtOH
Fig. 21 Overlay of the emission decays of RuBpy in ethanol and the RuBpy templated MOFs
RWLC-6
Fig. 22 Proposed energy level diagram for the fast and slow phase decays associated with RuBpy
encapsulated within RWLC-6 relative to RuBpy in EtOH
Guest-Based Photoactive Porous Materials Based upon Zn-Carboxylate Metal. . .
179