Crystal structure of (2-{[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl](5-methyl-2H-pyrrol-2-ylidene)methyl}-5-methyl-1H-pyrrolido-κ2N,N′)difluoridoboron

Abstract

The title compound, C25H31BF2N2O, is a potential boron tracedrug in boron neutron capture therapy (BNCT), in which the B atom adopts a distorted BN2F2 tetrahedral geometry: it is soluble in dimethyl sulfoxide, dimethylformamide and methanol. The pyrrolylidenemethylpyrrole triple fused ring system is almost planar (r.m.s. deviation = 0.031 Å) and subtends a dihedral angle of 47.09 (5)° with the plane of the pendant phenol ring. The phenol –OH group is blocked from forming hydrogen bonds by the adjacent bulky tert-butyl groups. In the crystal, inversion dimers linked by pairs of very weak C—H...F interactions generate R22(22) loops.

Keywords

• crystal structure
• boron tracedrug
• boron neutron capture therapy (BNCT)