scholarly journals The Influence of Halogenated Hypercarbon on Crystal Packing in the Series of 1-Ph-2-X-1,2-dicarba-closo-dodecaboranes (X = F, Cl, Br, I)

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1200
Author(s):  
Miroslav Havránek ◽  
Maksim A. Samsonov ◽  
Josef Holub ◽  
Zdeňka Růžičková ◽  
Ladislav Drož ◽  
...  
Keyword(s):  
Solid State ◽  
Electrostatic Potential ◽  
Crystal Packing ◽  
Heat Of Formation ◽  
Solid State Structures

Although 1-Ph-2-X-closo-1,2-C2B10H10 (X = F, Cl, Br, I) derivatives had been computed to have positive values of the heat of formation, it was possible to prepare them. The corresponding solid-state structures were computationally analyzed. Electrostatic potential computations indicated the presence of highly positive σ-holes in the case of heavy halogens. Surprisingly, the halogen•••π interaction formed by the Br atom was found to be more favorable than that of I.

A theoretical insight into non-covalent supramolecular interactions in the solid state structures of two octahedral iron(iii) complexes

CrystEngComm ◽  
2020 ◽  
Vol 22 (35) ◽  
pp. 5731-5742 ◽  
Author(s):  
Tanmoy Basak ◽  
Antonio Frontera ◽  
Shouvik Chattopadhyay
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Crystal Packing ◽  
Supramolecular Interactions ◽  
Interaction Energies ◽  
Π Interactions ◽  
Solid State Structures ◽  
Theoretical Insight ◽  
Insight Into

The nature and characteristics of the C–H⋯π interactions that play an important role in crystal packing of two iron(iii) complexes have been discussed. The DFT calculations have been conducted to determine the interaction energies in these complexes.

Solid-State Structures of Double-Long-Chain Imidazolium Ionic Liquids: Influence of Anion Shape on Cation Geometry and Crystal Packing

2011 ◽  
Vol 11 (5) ◽  
pp. 1974-1988 ◽  
Author(s):  
Xinjiao Wang ◽  
Carola S. Vogel ◽  
Frank W. Heinemann ◽  
Peter Wasserscheid ◽  
Karsten Meyer
Keyword(s):  
Ionic Liquids ◽  
Solid State ◽  
Crystal Packing ◽  
Imidazolium Ionic Liquids ◽  
Solid State Structures ◽  
Long Chain

The Influence of the Axial Ligand on the Solid-State Structures of Pentacoordinate Manganese Tetraphenylporphyrin Complexes

1998 ◽  
Vol 51 (9) ◽  
pp. 853 ◽  
Author(s):  
Peter Turner ◽  
Maxwell J. Gunter ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Solid State ◽  
Metal Ion ◽  
Crystal Packing ◽  
Intrinsic Property ◽  
Axial Ligand ◽  
Ligand Field ◽  
Independent Molecules ◽  
Solid State Structures ◽  
Packing Interactions

The crystal structures of Mn(tpp)(NCO), Mn(tpp)(CH3CO2).0·5C7H8, Mn(tpp)(NCS).0·5C7H8, Mn(tpp)(Br).C7H8, Mn(tpp)(I).C7H8 and the previously reported structures Mn(tpp)(Cl).(CH3)2CO, Mn(tpp)(Cl).C7H8, Mn(tpp)(NO2).C6H6, Mn(tpp)(NO3).2C6H6, Mn(tpp)(OSO3H), Mn(tpp)(H2O).-SO3CF3 and Mn(tpp)(CN).CHCl3 are used to assess the role of the axial anion in the crystal packing of pentacoordinate manganese tetraphenylporphyrin complexes. A comparison of the packing strategies adopted by the toluene solvates suggests that the axial anion can sterically determine the lattice packing motif. Amongst the structures examined, there appears to be a hierarchy of packing strategies led by the elegant ‘slot together’ assembly pattern underpinning the Mn(tpp)(Br).C7H8 and Mn(tpp)(Cl).C7H8 lattices. The metrical parameters that have been used to assess intercomplex interactions in the solid state are shown to be crystal packing sensitive. This is clearly evident in the structure of Mn(tpp)(I).C7H8 which has two crystallographically independent molecules. The displacement of the metal ion from the porphyrin core is determined by the axial ligand field; however, this otherwise intrinsic property is also crystal packing dependent. That is, the iodo ligand field itself is modulated by crystal packing interactions. The isomorphous Mn(tpp)(CH3CO2).0·5C7H8 and Mn(tpp)(NCS).0·5C7H8 structures, which also have two crystallographically independent molecules, indicate that the axial ligand field strength can influence intercomplex interactions in the solid state, by moderating charge donation from the porphyrin to the metal.

scholarly journals Structural Elucidation of Enantiopure and Racemic 2-Bromo-3-Methylbutyric Acid

Chemistry ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 691-699
Author(s):  
Rüdiger W. Seidel ◽  
Nils Nöthling ◽  
Richard Goddard ◽  
Christian W. Lehmann
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Crystal Packing ◽  
Structural Elucidation ◽  
Monocarboxylic Acids ◽  
Triclinic Crystal System ◽  
X Ray Crystallography ◽  
Methylbutyric Acid ◽  
Solid State Structures

Halogenated carboxylic acids have been important compounds in chemical synthesis and indispensable research tools in biochemical studies for decades. Nevertheless, the number of structurally characterized simple α-brominated monocarboxylic acids is still limited. We herein report the crystallization and structural elucidation of (R)- and rac-2-bromo-3-methylbutyric acid (2-bromo-3-methylbutanoic acid, 1) to shed light on intermolecular interactions, in particular hydrogen bonding motifs, packing modes and preferred conformations in the solid-state. The crystal structures of (R)- and rac-1 are revealed by X-ray crystallography. Both compounds crystallize in the triclinic crystal system with Z = 2; (R)-1 exhibits two crystallographically distinct molecules. In the crystal, (R)-1 forms homochiral O–H···O hydrogen-bonded carboxylic acid dimers with approximate non-crystallographic C2 symmetry. In contrast, rac-1 features centrosymmetric heterochiral dimers with the same carboxy syn···syn homosynthon. The crystal packing of centrosymmetric rac-1 is denser than that of its enantiopure counterpart (R)-1. The molecules in both crystal structures adopt a virtually identical staggered conformation, despite different crystal environments, which indicates a preferred molecular structure of 1. Intermolecular interactions apart from classical O–H···O hydrogen bonds do not appear to have a crucial bearing on the solid-state structures of (R)- and rac-1.

scholarly journals “Anti-Electrostatic” Halogen Bonding

2020 ◽  
Author(s):  
Jana Holthoff ◽  
Elric Engelage ◽  
Robert Weiss ◽  
Stefan Huber
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Gas Phase ◽  
Electrostatic Potential ◽  
Lewis Acids ◽  
Halogen Bonding ◽  
Halide Complexes ◽  
Self Association ◽  
Solid State Structures ◽  
Van Der Waals Radii

Halogen bonding (XB) is often described as being driven predominantly by electrostatics, and thus adducts between <i>anionic</i> XB donors (halogen-based Lewis acids) and anions seem counter­intuitive. Such “anti-electrostatic” XBs have been predicted theoretically, but there are currently no experimental examples based on organic XB donors. Herein, we report the synthesis of two negatively charged organoiodine derivatives, which were subsequently investigated towards their ability to form “anti-electrostatic” XBs with anions. Even though the electrostatic potential is universally negative across the surface of both compounds, DFT calculations indicate kinetic stabilization of their halide complexes in the gas phase and particularly in solution. Experimentally, self-association of the anionic XB donors was observed in solid-state structures, resulting in dimers, trimers and infinite chains. In addition, co-crystals with halides were obtained which featured XB adducts between two or even three anions. The bond-lengths of all observed interactions are 14-21% shorter than sum of the van-der-Waals radii.

Synthesis and crystal and molecular structures of N,N′-methylenedipyridinium tetrachlorozincate(II) and N,N′-methylenedipyridinium tetrachlorocadmate(II)

2011 ◽  
Vol 65 (4) ◽  
Author(s):  
Mahmoud Al-Ktaifani ◽  
Mwaffak Rukiah
Keyword(s):  
Solid State ◽  
Crystal Packing ◽  
Molecular Structures ◽  
Rotational Axis ◽  
X Ray Diffraction ◽  
Ionic Compounds ◽  
Complex Salts ◽  
Ring Centroid ◽  
Solid State Structures ◽  
Short Contacts

AbstractTreatment of N,N′-methylenedipyridinium dichloride [C5H5N-CH2-NC5H5]Cl2 with MCl2 (M = Zn or Cd) in aqueous solution gives the organic-inorganic hybrid ionic compounds [C5H5N-CH2-NC5H5] · [MCl4]. Both complex salts were fully characterised by multinuclear NMR spectroscopy, elemental analysis, and their molecular structures confirmed by powder X-ray diffraction studies. The most striking feature in both solid state structures was the presence of the C…Cl-M short contacts between the organic [C5H5N-CH2-NC5H5] dication and inorganic [MCl4] anion, which led to different crystal packing. For [C5H5N-CH2-NC5H5]·[ZnCl4], the C…Cl-Zn interactions led to the alternating arrangement of [C5H5N-CH2-NC5H5]2+[ZnCl4]2− to form 1-D chains in the direction [010], and each individual chain had a two-fold rotational axis along the b axis, while for [C5H5N-CH2-NC5H5] · [CdCl4] the C…Cl-Cd associations gave 2-D network. In both solid state structures, the presence of Cl-ring centroid distances gave a strong indication of some form of Cl-π interactions.

scholarly journals “Anti-Electrostatic” Halogen Bonding

2020 ◽  
Author(s):  
Jana Holthoff ◽  
Elric Engelage ◽  
Robert Weiss ◽  
Stefan Huber
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Gas Phase ◽  
Electrostatic Potential ◽  
Lewis Acids ◽  
Halogen Bonding ◽  
Halide Complexes ◽  
Self Association ◽  
Solid State Structures ◽  
Van Der Waals Radii

Halogen bonding (XB) is often described as being driven predominantly by electrostatics, and thus adducts between <i>anionic</i> XB donors (halogen-based Lewis acids) and anions seem counter­intuitive. Such “anti-electrostatic” XBs have been predicted theoretically, but there are currently no experimental examples based on organic XB donors. Herein, we report the synthesis of two negatively charged organoiodine derivatives, which were subsequently investigated towards their ability to form “anti-electrostatic” XBs with anions. Even though the electrostatic potential is universally negative across the surface of both compounds, DFT calculations indicate kinetic stabilization of their halide complexes in the gas phase and particularly in solution. Experimentally, self-association of the anionic XB donors was observed in solid-state structures, resulting in dimers, trimers and infinite chains. In addition, co-crystals with halides were obtained which featured XB adducts between two or even three anions. The bond-lengths of all observed interactions are 14-21% shorter than sum of the van-der-Waals radii.

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