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Crystal chemistry of N-(p-tolyl)tetrachlorophthalimide and of its channel inclusion complexes*

1981; De Gruyter; Volume: 157; Issue: 1-2 Linguagem: Inglês

10.1524/zkri.1981.157.1-2.1

2196-7105

Metal complexes synthesis and properties

Abstract N-(p-tolyl)tetrachlorophthalimide (TTP) has three polymorphic forms: α , β , γ . The crystal structure of γ is reported here: stable in the range = 100–214°C, can be quenched to room temperature, monoclinic yellow needles; P 2 1 / c ; a = 25.02(1) Å, b = 3.97(1) Å, c = 30.96(1) Å, β = 100.9(5)°, Z = 8. In γ -TTP the molecules are stacked along the short b axis, adjacent stacks being linked across centres of symmetry by strong – Cl....O = C – interactions [ d (Cl – O) = 2.90 Å]; the overall packing is unusual in that successive slices of crystal [parallel to (100)] contain molecules of different orientations. TTP forms complexes with many aromatic molecules (composition generally 4 TTP · [guest]), also crystallizing as yellow needles. These complexes have now been shown to be isostructural channel inclusion complexes, with the TTP molecules arranged in corrugated sheets pierced by channels containing the guest molecules. The structure of the 4 TTP · [ o -xylene] complex has been determined from four-circle diffractometer measurements (graphite-monochromated Mo Kα , ∼4200 reflections). The TTP molecules are arranged according to a monoclinic sub-cell, with a = 22.267(2) Å, b = 3.911(4) Å, c = 19.909(2) Å, β = 106.4(1)°, C 2, Z = 4; the true cell, taking the o -xylene molecules into account, is actually triclinic. The subcell is common to all the complexes but the true cells depend on the nature of the guest. Only molecules with shapes appropriate to the channel dimensions can form inclusion complexes with TTP; perylene and fluoranthene form 1 : 1 complexes with TTP which are probably π – π * charge transfer complexes. The TTP molecules have the same conformation in both the γ-phase and the inclusion complexes, whereas the two parts of the molecule are mutually perpendicular in the α-phase. This accounts for the differences in colour between these two groups of crystals. The thermal stability of the TTP polymorphs and inclusion complexes was studied by DTA, DSC, TGA and high-temperature X-ray diffraction. Some 4 TTP · [guest] complexes decompose to α-TTP and others to γ-TTP.