Relationship between the Skew Angle and Interplanar Distance in Four Bis(phthalocyaninato)lanthanide(III) Tetrabutylammonium Salts ([NBun4][LnIIIPc2]; Ln = Nd, Gd, Ho, Lu)

Four crystal structures of the title complexes have been analyzed by X-ray crystallography. 1: C 80 H 68 N 17 Nd, a = 17.0545(6) Å, c = 22.807(3) Å, tetragonal, P 4/ ncc, Z = 4. 2: C 80 H 68 N 17 Gd, a = 17.399(8) Å, c = 11.377(6) Å, tetragonal, P 42 1 2, Z = 2. 3: C 80 H 70 N 17 OHo, a = 18.096(5) Å, c = 11.079(6) Å, tetragonal, P 42 1 2, Z = 4. 4: C 80 H 70 N 17 OLu, a = 18.171(3) Å, c = 10.987(4) Å, tetragonal, P 4/ nmm, Z = 2. The [Ln III Pc 2 ] - and [NBu n 4 ] + ions in each crystal stack alternately in a column along the 4-fold axis. The Ln(III) cation of each [Ln III Pc 2 ] - is eight-coordinated by two phthalocyanato dianions (Pc). The interplanar distances between the two Pc rings have a linear relationship to the ionic radii of the central Ln(III) cations. The skew angles between the two Pc rings are 6.2, 34.4, 43.2, and 45.0° for the Nd, Gd, Ho, and Lu complexes, respectively. The skew angle seems to depend on the strength of the π−π interaction between the two Pc rings.