Interplay between non-covalent interactions in complexes and crystals with halogen bonds

Dihalomethanes as Bent Bifunctional XB/XB‐Donating Building Blocks for Construction of Metal‐involving Halogen Bonded Hexagons

“…at bond critical points( 3, À1) for short XCH 2 -X···X M -M contacts (Table S12, the Supporting Information) are typical for noncovalent interactions involving halogena toms. [6] We have defined energies for these contacts accordingt ot he procedures proposed by Espinosa et al, [16] Vener et al, [17] and Tsirelson et al [18] (the latter approach was developed exclusivelyf or noncovalentc ontacts involvingh alogen atoms), and one can state that their estimated strengthsa re in the range 1.3-3.2 kcal mol À1 .T he balance between the Lagrangian kinetic energy G(r)a nd potential energy density V(r)a tt he bond criticalp oints (3, À1) for discussed contacts ( Figure 6) in model associates reveals that ac ovalent contribution in these interactions is totally absent. [19] Our processing of available CCDC data shows that hexagonlike arrays are rather commons tructural motives for adducts of trans-bis(halide) complexes and halomethanes.…”

Polymeric Lead(II) Iodoacetate: Pb···I and I···I Non‐Covalent Interactions in the Solid State

“…The low magnitude of the electron density, positive values of the Laplacian of electron density, and very close to zero positive energy density in these BCP's as well as small values of Wiberg bond indices for appropriate contacts are typical for non‐covalent interactions. Their energies were calculated according to several procedures proposed by Espinosa et al, Vener et al and Tsirelson et al (the last approach was developed exclusively for non‐covalent contacts involving iodine atoms); the estimated strengths vary in the ranges 1.6–2.5 and 0.9–1.7 kcal/mol, respectively. The balance between the Lagrangian kinetic energy G( r ) and potential energy density V( r ) at the BCPs for I ··· I and Pb ··· I interactions reveals that a covalent contribution in these weak contacts is negligible …”

“…[44] [d] E int = 0.67G(r). [44] [e] These halogen-halogen non-covalent interactions are crystal packing induced type I short contacts, but not "true" halogen bonds (type II short contacts) according to the IUPAC definition. [46] Theoretically, two different cases could be imagined for Pb···I contacts.…”

Four‐Center Nodes: Supramolecular Synthons Based on Cyclic Halogen Bonding

“…in bond critical points (3, À1) for short contacts listed in Ta ble S5 are typical for noncovalent interactions involving halogen atoms. [8d, 11b, 24] We have defined energies for these contacts according to several procedures proposed by Espinosa et al, [25] Vener et al, [26] and Tsirelson et al [27] (the latter approachw as developed exclusively for noncovalent contactsinvolving Br and Ia toms), and one can state that their estimated strengths are in the range 0.6-2.9 kcal mol À1 .T he balance between the Lagrangian kinetice nergy G(r)a nd potential energy density V(r)a tt he BCPs (3, À1) for discussed contacts ( Figures 7a nd S11) in model associates reveals that a covalentc ontribution in thesei nteractions is totally absent. [28] We have calculated the effective atomicc harges on the bromine ligands (À0.27 e)a nd bromine atoms of the CNC 6 H 4 Br moieties (0.12 e)i nm odel associate 1a by using the natural bond orbital( NBO) partitioning scheme, [29] and it is clear that formation of the four-center node in this system is favorable from the chargec onsiderations.…”