Nitro-sonium complexation by the tetra-phospho-nate cavitand 5,11,17,23-tetra-methyl-6,10:12,16:18,22:24,4-tetra-kis-(phenyl-phospho-nato-κ2O, O)resorcin(4)arene

Abstract

The crystal structure of a new supra-molecular complex between the tetra-phos-pho-nate cavitand 5,11,17,23-tetra-methyl-6,10:12,16:18,22:24,4-tetra-kis(phenyl-phospho-nato-κ²O,O')resorcin(4)arene and the nitrosyl cation NO⁺, as the BF₄^- salt, is reported. The complex, of general formula [(C₅₆H₄₄P₄O₁₂)(NO)]BF₄·CH₂Cl₂ or NO@Tiiii[H, CH₃, C₆H₅] BF₄·CH₂Cl₂, crystallizes in the space group P-1. The nitrosyl cation is disordered over two equivalent positions, with occupancies of 0.503 (2) and 0.497 (2), and inter-acts with two adjacent P=O groups at the upper rim of the cavitand through dipole-charge inter-actions. In the lattice, the cavitands are connected through a series of C-H⋯π inter-actions involving the methyl and methyl-enic H atoms and the aromatic rings of the macrocycle. The structure is further stabilized by the presence of C-H⋯F inter-actions between the hydrogen atoms of the cavitands and the F atoms of the tetra-fluorido-borate anion. As a result of the disorder, the lattice di-chloro-methane mol-ecules could not be modelled in terms of atomic sites, and were treated using the PLATON SQUEEZE procedure [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The complexation process has also been studied in solution through NMR titrations.

Keywords: C—H⋯F inter­actions; C—H⋯π inter­actions; crystal structure; inclusion compounds; nitro­sonium ion; tetra­phospho­nate cavitands.