A structural spproach to the strength evaluation of linear chalcogen bonds

The experimental structural features of chalcogen bonding (ChB) interactions in over 34,000 linear fragments R–Ch⋯A (Ch = S, Se, Te; R = C, N, O, S, Se, Te; A = N, O, S, Se, Te, F, Cl, Br, I) were analyzed. The bond distances dR–Ch and the interaction distances dCh⋯A were investigated, and the functions δR–Ch and δCh⋯A were introduced to compare the structural data of R–Ch⋯A fragments involving different Ch atoms. The functions δR−Ch and δCh⋯A were calculated by normalizing the differences between the relevant bond dR–Ch and ChB interaction dCh⋯A distances with respect to the sum of the relevant covalent (rcovR + rcovCh) and the van der Waals (vdW) radii (rvdWCh + rvdWA), respectively. A systematic comparison is presented, highlighting the role of the chalcogen involved, the role of the R atoms covalently bonded to the Ch, and the role of the A species playing the role of chalcogen bond acceptor. Based on the results obtained, an innovative approach is proposed for the evaluation and categorization of the ChB strength based on structural data

Synthesis and molecular structure of [((CO)(3)RuBr(2))(2)(mu-SePh)(2)Ru(CO)(4)] cluster with a Ru(3)Se(2) chain core

Treatment of ruthenium carbonyl, [Ru(3)(CO)(12)] with phenylseleno tribromide PhSeBr(3) afforded a new triruthenium cluster, [(CO)(10)Br(4)Ru(3)(mu-SePh)(2)](1). Its molecular structure was determined by single crystal XRD method (P2(1)/c; a = 10.514(3) angstrom; b = 10.814(3) angstrom; c = 19.063(5) angstrom; beta = 105.064(4)degrees; V = 2093.1(10) angstrom(3)) and shown to have two lateral Ru(CO)(3)Br(2) units attached via two PhSe bridges to a Ru(CO)(4) center forming a chain-like Ru-Se-Ru-Se-Ru cluster core. This is in contrast with a recently reported reaction of PhTeBr(3) with [Ru(3)(CO)(12)] which formed a monomeric complex of ruthenium-dicarbonyl-dibromo fragment coordinating two PhTeBr ligands, [(CO)(2)RuBr(2)(PhTeBr)(2)]. (C) 2010 Elsevier B.V. All rights reserved

Regio- and stereo-specific addition of organotellurium trihalides to ferrocenylacetylene: Molecular and crystal structure of (Z)-halovinyl organotellurium dihalides

Organotellurium(IV) trihalides RTeX(3) (X = Br, I) reacts readily with ferrocenylacetylene to give (Z)-products of electrophilic addition to C-C triple bond: (Z)-FcXC = CTeX(2)R (R = Ph, X = Br (1) or I (2); R = trans-8-ethoxy-4-cyclooctenyl, X = Br (3)). In case of PhTeX(3) (X = Br or I) the room temperature reaction is spontaneous and the structure of the product does not depends on the polarity of the solvent used; this is in contrast to the reaction of aryl-acetylenes with RTeBr(3) which were reported to afford (E)-bromovinyl aryltellurium dibromides in methanol and its (Z)-isomer in benzene. Molecular and crystal structures of new compounds and effect of bulky and electron-rich ferrocenyl substituent on the reactivity of acetylene moiety are discussed in this paper.

Cyclodimerization of phenyliodoacetylene with elemental tellurium: New pathway to 1.3-ditellurofulvenes

Thermal reaction between PhC Cl and powdered Te afforded a mixture of (E)-4-iodo-2-(iodo(phenyl)-5-phenyl-1,3-ditellurofulvene (1) and (Z)-4-iodo-2-(iodo(phenyl)-5-phenyl-1-(diiodo),3-ditellurofulvene (2), which was subsequently reduced to (Z)-4-iodo-2-(iodo(pheny1)-5-phenyl-1,3-ditellurofulvene (3). Formation of 1 and 3 as the thermodynamically most stable products has been rationalized using density functional theory (DFT) calculations. Molecular structures of 1-3 were established crystallographically. In the solid state the coordination sphere of both tellurium atoms in 2 is extended by weak intermolecular Te center dot center dot center dot pi interactions with the solvate molecule of toluene which completes the pseudo-trigonal bipyramidal coordination geometry around each Te atom and assembles 2 into the chains along the crystallographic c-axis. (c) 2010 Elsevier B.V. All rights reserved

Halogen Bonding and CO-Ligand Blue-Shift in Hybrid Organic—Organometallic Cocrystals [CpFe(CO)2X] (C2I4) (X = Cl, Br)

This work is focused on the complex interplay of geometry of I· · · X halogen bonds (HaB) and intermolecular interaction energy in two isomorphic cocrystals [CpFe(CO)2X] (C2 I4 ) (X = Cl (1), Br (2)). Their IR-spectroscopic measurements in solid state and solution demonstrate the blue-shift of CO vibration bands, resulting from I· · · X HaB. The reluctance of their iodide congener [CpFe(CO)2 I] to form the expected cocrystal [CpFe(CO)2 I] (C2 I4 ) is discussed in terms of different molecular electrostatic potential (MEP) of the surface of iodide ligands, as compared with chloride and bromide, which dictate a different angular geometry of HaB around the metal-I and metal-Br/Cl HaB acceptors. This study also suggests C2 I4 as a reliable HaB donor coformer for metal-halide HaB acceptors in the crystal engineering of hybrid metal–organic systems. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Mixed-valent ferrocenyltellurenyl halides. Synthesis, electrochemistry and unusual molecular structure

Halogenation of diferrocenyl ditelluride (Fc(2)Te(2)) allowed corresponding isostructural ferrocenyltellurenyls [FcTeX] (X = Cl (6), Br (7), X = I (8)). Their molecular structures in the solid state confirm them to be mixed-valent FcTe-TeX(2)Fc, however, the single band in Te-125 NMR spectrum of 8 and electrochemical data suggests the monomeric [FcTeX] structure in the solution at room temperature. Remarkable bent of non-halogenated atom of Te towards the Fe atom observed in the solid state structures of 6-8, removes the Te atom from the plane of the related Cp ring (15 degrees-20 degrees) and may indicate the interaction of filled nonbonding 3d orbitals of Fe with the appropriate Te localized LUMO. (C) 2013 Elsevier B. V. All rights reserved