Synthesis, crystal structures, two-photon absorption and biological imaging application of two novel bent-shaped pyrimidine derivatives

Two novel bent-shaped D-pi-A-pi-D chromophore molecules, 2-pyrazolyl-4,6-bis (4-N,N-ethylaminostyryl)pyrimidine (Z1) and 2-imidazolyl-4,6 bis- (4-N,N- ethylaminostyryl) pyrimidine (Z2), were synthesized and fully characterized. It was found that the both bent-shaped chromophore molecules crystallize in the orthorhombic system, space group of P2(1)2(1)2(1), The photophysical properties and the connections between structure and properties of the chromophores were investigated both experimentally and theoretically. It was revealed that both absorption and single-photon excited fluorescence (SPEF) spectra show remarkable bathochromic shifts with increasing polarity of the solvents. The two chromophores have strong two-photon excited fluorescence and large two-photon absorption cross-sections in the near-infrared range. Additionally, two-photon microscopy (TPM) fluorescent imaging of BEL-7402 cells labeled with the Z1 and Z2 revealed their potential application as a biological fluorescent probe. (C) 2013 Elsevier Ltd. All rights reserved.