Yury V. Torubaev

Antiferromagnetic complexes with the metal-metal bond XXVIII. Synthesis and molecular structure of the antiferromagnetic cluster [CpCr(μ-SCMe3)]2(μ4-S) [PtMe3(μ-I)]2

Abstract The reaction of [CpCr(μ-SCMe 3 )] 2 (μ-S) ( 1 ) with [PtMe 3 I] 4 in hot benzene leads to the formation of the tetranuclear cluster I[CpCr(μ-SCMe 3 )] 2 (μ 4 -S)[PtMe 3 (μ-I)] 2 ( 2 ). According to X-ray data, cluster 2 contains a molecule of 1 (Cr-Cr 2.761(9) A, Cr-S-Cr 70.1(4)°), coordinated to a diplatinum fragment via a μ 4 -S atom (Pt-S 2.583(10) and 2.560(9) A). 2 has antiferromagnetic properties (−2 J = 202 cm −1 ) due to the interaction between two paramagnetic Cr(III) centers ( S = 3/2).

Metal-metal bond cleavage in [Cp(CO)2Fe-Fe(CO)2Cp] under the action of organotellurium(IV)tribromides

The oxidation of [CpFe(CO)2]2 by RTeBr3 allowed the corresponding organotellurodibromide complexes CpFe(CO)2TeBr2R (R=Ph, cyclo-(C8H12)(OMe). Their structural features (as determined by single-crystal X-ray diffraction analysis) are discussed.

First structural evidence of a Se–Br–Br halogen-bonded molecular complex

The halogenation of 2,6-dibromo-9-selenabicyclo[3.3.1]-nonane 1 with 1 equivalent of molecular dihalogens (Br2 and I2) afforded a 1 : 1 molecular complex 1–X2 (X = Br (2); X = I (3)), while an excess of Br2 resulted in the ionic species [C8H12Br2SeBr]Br5− (4). X-ray crystallographic data and the nature of Se⋯Br non-covalent bonding in the solid state and solution is discussed.

Organometallic halogen bond acceptors: directionality, hybrid cocrystal precipitation, and blueshifted CO ligand vibrational band

Iron cyclopentadienyl carbonyl-halide and -chalcogenolate complexes CpFe(CO)2X (X = Cl, Br, I, TePh, SPh) readily afford cocrystals with the bidentate halogen bond donor 1,4-diiodotetrafluorobenzene (p-DITFB) under slow evaporation or vapor diffusion conditions. The same microcrystalline [CpFe(CO)2TePh](p-DITFB) product instantly precipitates upon mixing p-DITFB and CpFe(CO)2TePh in hexane solution. Supramolecular [CpFe(CO)2X(p-DITFB)]n chains in the cocrystals are assembled by halogen bonds (XB) between the electrophilic area of iodine atoms of p-DITFB and the nucleophilic area of X in CpFe(CO)nX. The 5–10 cm−1 hypsochromic shift of the CO stretching bands in the IR spectra of [CpFe(CO)2X(p-DITFB)] cocrystals is explained by the pronounced electron-withdrawing effect of halogen bonding (XB), as supported by DFT calculations. The observed influence of the nature of the XB acceptor (X) on the XB geometry is described in terms of hybridization and electrostatic surface potential (ESP) mapping.

Self-assembly of conducting cocrystals via iodine⋯π(Cp) interactions

Conducting crystals of alternating ferrocene and diiodoacetylene units assembled into supramolecular 1-D chains via I⋯π(Cp) halogen bonds were prepared and structurally characterized. Their structure and conductivity were compared with the ferrocene cocrystals with phenyliodoacetylene (C6H5C2I) and 1,4-di(ethynyliodo)phenylene. Electrical conductivity measurements of the ferrocene-based cocrystals revealed comparatively high electron–hole type conductivity in the ferrocene (FcH)–diiodoacetylene (C2I2) pair, a 3-order decrease in combination with the 1,4-di(ethynyliodo)phenylene linker, and it is virtually extinguished with the monotopic 1,2-phenyliodoacetylene. The increased electric conductivity of compound 1 is rationalized in terms of a weak charge transfer through the I⋯πCp halogen bonds in the [Cp–Fe–Cp⋯I–CC–I⋯]n polymeric chains.