A cationic poly(ferrocenylboronium) derivative was prepared by postpolymerization modification reaction of poly(ferrocenylbromoborane) (P1) with 4,4′-dinonyl-2,2′-bipyridyl (Rbipy). The polymer was found to show good stability under ambient conditions and was well soluble in polar organic solvents. Dialysis in MeOH allowed for isolation of a high molecular weight fraction that was further examined. The number-average of repeat units was estimated by GPC analysis relative to PS standards to be n =17, and MALDI−TOF analysis confirmed the chemical structure of the polymer repeat units. A characteristic purple color was observed in solution, which is due to charge-transfer from the electron-rich ferrocenyl to the electron-deficient bipyridylboronium moieties along the polymer main chain.

Starting from doubly lithiated ferrocene [Fe(η5-C5H4)2]3Li6(tmeda)2 (1), the corresponding thf adduct [Fe(η5-C5H4)2]2Li4(thf)6 (3) was prepared by recrystallization of 1 from thf. In contrast to 1, which features six Li+ cations surrounded by 1,1′-ferrocenediyl fragments in a carousel arrangement, compound 3 contains only two ferrocenediyl anions bridged by four Li+ cations. This comparison clearly reveals the strong impact of different supporting ligands on the solid-state structures of lithiated ferrocenes. The doubly magnesiated and zincated derivatives [Fe(η5-C5H4)2]3Mg3(tmeda)2 (4) and [Fe(η5-C5H4)2]2Zn2(tmeda)2 (6) were synthesized via salt metathesis using 1 and MgCl2 or ZnCl2, respectively. Even though Mg2+ and Zn2+ are chemically related ions, the solid-state structures of 4 and 6 turned out to be distinctly different. Compound 4 possesses a cluster structure reminiscent of the lithiated aggregate 1, whereas 6 represents the first example of a first-row transition metal-bridged [1.1]-ferrocenophane (anti-conformation). All three doubly metallated ferrocenes 3, 4, and 6 are suitable reagents for the preparation of 1,1′-disubstituted ferrocenes as has been exemplified for the synthesis of Fe(η5-C5H4SiMe3)2 (5). We have also shown that 5 can be generated in yields exceeding 90% from Fe(η5-C5H4Br)2, Me3SiCl, and Rieke magnesium.

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

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2-{1-[(4-Chloroanilino)methylidene]ethyl}pyridinium chloride methanol solvate, C(13)H(13)ClN(3)(+) x Cl(-) x CH(3)OH, (I), crystallizes as discrete cations and anions, with one molecule of methanol as solvent in the asymmetric unit. The N-C-C-N torsion angle in the cation indicates a cis conformation. The cations are located parallel to the (\overline{2}02) plane and are connected through hydrogen bonds by a methanol solvent molecule and a chloride anion, forming zigzag chains in the direction of the b axis. The crystal structure of 2-{1-[(4-fluoroanilino)methylidene]ethyl}pyridinium chloride, C(13)H(13)FN(3)(+) x Cl(-), (II), contains just one anion and one cation in the asymmetric unit but no solvent. In contrast with (I), the N-C-C-N torsion angle in the cation corresponds with a trans conformation. The cations are located parallel to the (100) plane and are connected by hydrogen bonds to the chloride anions, forming zigzag chains in the direction of the b axis. In addition, the crystal packing is stabilized by weak pi-pi interactions between the pyridinium and benzene rings. The crystal of (II) is a nonmerohedral monoclinic twin which emulates an orthorhombic diffraction pattern. Twinning occurs via a twofold rotation about the c axis and the fractional contribution of the minor twin component refined to 0.324 (3). 2-{1-[(4-Fluoroanilino)methylidene]ethyl}pyridinium chloride methanol disolvate, C(13)H(13)FN(3)(+) x Cl(-) x 2 CH(3)OH, (III), is a pseudopolymorph of (II). It crystallizes with two anions, two cations and four molecules of methanol in the asymmetric unit. Two symmetry-equivalent cations are connected by hydrogen bonds to a chloride anion and a methanol solvent molecule, forming a centrosymmetric dimer. A further methanol molecule is hydrogen bonded to each chloride anion. These aggregates are connected by C-H...O contacts to form infinite chains. It is remarkable that the geometric structures of two compounds having two different formula units in their asymmetric units are essentially the same.