3-Phenyl-1,4-dihydrobenzo[e][1,2,4]triazinyl radicals with the N(1) position substituted with naphth-2-yl (1 b), naphth-1-yl (1 c), pyren-1-yl (1 d), anthracen-9-yl (1 e), 2-trifluoromethylphenyl (1 f), 3-trifluoromethylphenyl (1 g), and 2-iodophenyl (1 h) were characterized by using single-crystal X-ray diffraction, variable-temperature magnetic susceptibility, and DFT computational methods. The substituent at N(1) is essentially orthogonal to the heterocycle plane in 1 f and 1 h, and with a high torsion angle in 1 c and 1 d. Radicals 1 c and 1 h form unusual infinite chains with crisscrossing hetero-co-facial π-π interactions, whereas radical 1 d forms analogous homo-co-facial arrangements. Infinite chains of homo-co-facial π-π dimers are found in 1 b, 1 f and 1 g; in the latter the position of the CF group controls the slippage of the dimers in the chain. No π-π parallel arrangements were found in 1 e. Magnetic susceptibility measurements demonstrated strong antiferromagnetic interactions in 1 b (J=-264±4 cm ) and 1 f (J=-134±1 cm ), while weak intradimer ferromagnetic interactions were found in 1 g (J =+21±1 and J =-15±1 cm ). Other derivatives exhibit typical weak antiferromagnetic exchange interactions in a range of -5 to -10 cm .

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A series of bent-core mesogens 2[m,n] and 3[4,6][6,n] derived from the 1,4-dihydrobenzo[e][1,2,4]triazin-4-yl radical and containing two partially fluorinated alkyl tails and the non-fluorinated derivative 1[12] were prepared and investigated by optical, thermal, XRD and magnetic methods.

A homologous series of disc-like 1,3,6-trisubstituted benzo [e] [1,2,4]triazin-4-yls 1[n] was synthesized and their structural, thermal, optical, magnetic, and electric properties were investigated. The results demonstrate that all members of the series display a Col h phase with clearing temperatures depending on the length of the alkoxy chains at the N(1) position, hence the shape of the disc. Powder XRD and magnetic data indicate a gradual change in the column diameter and magnetic behavior in the series in transition from half-disc in 1[0] (antiferromagnetic interactions) to full-disc geometry in the 1[12] homologue (ferromagnetic interactions with J/k B = + 7.5 K). Studies of binary systems revealed that a 1 : 1 mixture of 1[0] and 1[12] exhibits modest stabilization of the Col h phase with an expanded range, and magnetic behavior typical for 1[0] in the rigid phase obtained from the melt. Electric measurements demonstrated hole mobility of~10 À 3 cm 2 V À 1 s À 1 and dark conductivity of~10 À 11 Scm À 1 in the mixture and individual compounds. The latter is enhanced up to 4 times by simultaneous illumination with UV light.[a] Dr.