Planar Binuclear Phthalocyanine‐Containing Sandwich‐Type Rare‐Earth Complexes: Synthesis, Spectroscopy, Electrochemistry, and NLO Properties

The mixed cyclic tetramerization of 4,5‐bis(hexylthio)phthalonitrile and bis(diiminoisoindoline) with [M(acac) 3 ] · n H 2 O (M = Pr, Eu, Lu) as template in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in n ‐pentanol at reflux has provided binuclear phthalocyanine‐containing sandwich‐type rare‐earth complexes [{Pc(SC 6 H 13 ) 8 }M{BiPc(SC 6 H 13 ) 12 }M(SC 6 H 13 ) 8 ] (M = Pr, Eu, Lu; 1 – 3 ). These new binuclear phthalocyanine‐containing sandwich compounds have been characterized by a series of spectroscopic methods including mass spectrometry and 1 H NMR, electronic absorption, and IR spectroscopy in addition to elemental analysis. Their electrochemical data have also been obtained by cyclic voltammetry. In addition, the third‐order nonlinear optical properties of [{Pc(SC 6 H 13 ) 8 }Pr{BiPc(SC 6 H 13 ) 12 }Pr(SC 6 H 13 ) 8 ] ( 1 ) and [Pr{Pc(SC 6 H 13 ) 8 } 2 ] in toluene solution were studied comparatively by using the Z‐scan technique; effective imaginary third‐order molecular hyperpolarizabilities of 1.86 × 10 –11 and 1.56 × 10 –11 esu, respectively, were obtained, which indicates their potential application in the optical‐limiting field.