Synthesis, crystal structure and effect of deuterated solvents and temperature on visible and near infrared luminescence of N4-donor Schiff base lanthanide complexes

A series of lanthanide complexes [LnL(NO3)3]·CH3CN [Ln=Ce, (1
- Ce); Nd, (2
- Nd); Tb, (3
- Tb); Dy, (4
- Dy); Ho, (5
- Ho); Er, (6
- Er); Tm, (7
- Tm); Yb (8
- Yb)] have been synthesized by the reaction of N4 chelate ligand N,N'-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine (L) with lanthanide salts. Photoluminescence spectra of complexes 2
- Nd, 3
- Tb, 4
- Dy, and 8
- Yb show the strong characteristic luminescence from visible to near infrared (NIR) region. Further, the singlet state (32,467 cm−1) and the lowest triplet (23,202 cm−1) energy level of L are calculated, indicating that the energy transfer from L to Tb3+ ion is more effective than that to Dy3+ ion. An extended work is developed to discuss on the effect of deuterated reagent and temperature on luminescent properties of 3
- Tb and 8
- Yb.