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The title compound, C25H20N4O2, is a ditopic ortho-hydroquinone-based bis(pyrazol-1-yl)methane ligand. The dihedral angles between the planes of the pyrazole rings and their attached phenyl rings are 17.4 (3) and 5.9 (4)°. The pyrazole rings make a dihedral angle of 87.84 (16)°. One of the two hydroxy groups forms an intramolecular hydrogen bond to the other hydroxy group, whereas the second is involved in an intermolecular O—H[cdots, three dots, centered]N hydrogen bond. As a result of these intermolecular hydrogen bonds, helical chains running along the b axis are formed.
The crystal structure of the title compound, hexa-μ2-bromido-μ4-oxido-tetrakis[(diethyl ether)magnesium], [Mg4Br6O(C4H10O)4], determined from data measured at 173 K, differs from the previously known structure of diethyl ether magnesium oxybromide, which was determined from room-temperature data [Stucky & Rundle (1964 [triangle]). J. Am. Chem. Soc. 86, 4821–4825]. The title compound crystallizes in the tetragonal space group I An external file that holds a picture, illustration, etc. Object name is e-67-m1614-efi7.jpg, whereas the previously known structure crystallizes in a different tetragonal space group, namely P An external file that holds a picture, illustration, etc. Object name is e-67-m1614-efi7.jpg21 c. Both molecules have crystallographic An external file that holds a picture, illustration, etc. Object name is e-67-m1614-efi7.jpg symmetry and show almost identical geometric parameters for the Mg, Br and O atoms. The crystal of the title compound turned out to be a merohedral twin emulating a structure with apparent Laue symmetry 4/mmm, whereas the correct Laue group is just 4/m. The fractional contribution of the minor twin component converged to 0.462 (1).
Single crystals suitable for X-ray diffraction of (tBu2P)3Ga (monoclinic, space group Cc) were obtained from GaCl3 and two equivalents of Li[PtBu2] at room temperature in benzene. The phosphanylgallane (tBu2P)3Ga was also produced via a one-pot approach by reaction of GaCl3 with three or more than three equivalents of Li[PtBu2]. However, treatment of one equivalent of GaCl3 with one equivalent of Li[PtBu2] and subsequent protolysis yielded [tBu2PH2][tBu2P(GaCl3)2 - Li(Cl3Ga)2PtBu2]. Single crystals of this phosphonium salt (monoclinic, space group Cc) were obtained from benzene at room temperature.
To examine their luminescence behavior, two air-stable BN addition compounds were synthesized by the reaction of 5-fluoro-2-(2′-pyridyl)indole with 1,4- and 1,3-bis(bromo(methyl)boryl)benzene, respectively. Both BN adducts are luminescent. Their emission maxima (1,3-substituted BN adduct: 495 nm; 1,4-substituted BN adduct: 497 nm) are comparable with the value (490 nm) of the related mono-borylated benzene species, which is composed of a BPh2 fragment and a 5-fluoro-2-(2′-pyridyl) indole unit. The starting materials 1,4- and 1,3-bis(bromo(methyl)boryl)benzene were accessible by treatment of 1,4- or 1,3-bis(dibromoboryl)benzene with two equivalents of SnMe4. In addition, the results of the X-ray structure analyses of the B,B′-bis-5-fluoro-2-(2′-pyridyl)indolyl-complexed meta-bismethylborylbenzene fragment (9, triclinic, P1̅) as well as of 5-chloro-2-(2′-pyridyl)indole (2, monoclinic, P21/c) and 5-fluoro-2-(2′-pyridyl)indole (1, orthorhombic, Pca21) are reported. The pyridylindole derivatives of this approach were synthesized by an optimized two-step procedure from 2-acetylpyridine and 4-fluoro- or 4-chlorophenylhydrazine hydrochloride.