The trityl alcohols bearing three bromine or three iodine atoms at the para-positions of the aromatic units, have been known for more than a hundred years. In our case these compounds have been synthesized in one-pot sequence starting from the 1,4-dihalogenobenzenes via mono-lithiation and the successive reaction with diethylcarbonate. The compounds have been crystallized from different solvent mixtures leading to one structure of bromo-(A) and three structures of iodo trityl alcohols (B-D). The inclusion of dichloromethane (C) or benzene (D) in the crystalline lattices has been observed. In all cases the OH-p and halogen-p (and in one case the halogen-halogen and CH-O weak) contacts play crucial role in the crystal organisation. The common motif of the packing is the anti parallel arrangement of the trityl alcohol molecules into infinite chains. There is the gradual change in the intermolecular interactions going from the structures A and B, where only OH-p contacts between anti-parallel molecules are observed, to C with OH-p bifurcated contacts between anti-parallel molecules and further to the structure D, where practically no OH-p contacts are observed any longer. However in the case of D the splitting of the chain with anti-parallel molecules into two anti-parallel chains with parallelly assembled molecules takes place. These OH-p chains interact further with each other either via halogen-p or/and halogen-halogen, CH-O weak interactions. The shortest contacts found are 3.429 A ˚(1/A, Br-p) and 3.486 A ˚(2/D, I-p) while the longest contacts are 3.558 A ˚(1/A, Br-p) and 3.668 A ˚(2/B, I-p). No short contacts between the included solvent molecules and triiodo trityl alcohol within the structures C and D, have been observed. The quantum chemical calculations (DFT on the M05-2X/6-311G(d,p) level) gave the following interaction energies (kcal mol À1 ) between two neighbouring molecules of one ''OH-p chain'': À7.96 (A), À6.60 (B), À6.43 (C) and À6.45 (D), while the interaction energies via the halogen-p contacts vary from À2.17 to À3.58 kcal mol À1 (per one contact).

This report is concerned with an efficient, Cu(I)-mediated method for the radiosynthesis of [(18)F]trifluoromethyl arenes, abundant motifs in small molecule drug candidates and potential radiotracers for positron emission tomography. Three (18)F-labelled radiotracer candidates were synthesised from [(18)F]fluoride ions as proof of principle. The new protocol is widely applicable for the synthesis of novel radiotracers in high radiochemical yields.

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