Solution stoichiometry determines crystal stoichiometry in halogen-bonded supramolecular complexes (original) (raw)
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Journal of Structural Chemistry, 2001
There are two crystallographically independent saccharinate anions and 2,2′-bipyridine molecules. In the crystal structure, the packing is dominated by the net of hydrogen bonds between the saccharinato ligand ions and the water molecules and within these ions and molecules, and also by C-H … O contacts. IR spectra in characteristic regions of H 2 O, CO, and SO 2 stretching vibrations have been studied. The geometry of the water molecules is discussed with allowance for the spectroscopic and structural data. The appearance of the CO and SO 2 stretching vibrations in the spectrum of the compound correlates with the number of nonequivalent carbonyl and sulfonyl groups in the structure. Thermal DSC analysis was used to determine the decomposition rate and the stability of the complex.
CCDC 2085329: Experimental Crystal Structure Determination
2021
Doubledecker silsesquioxane (DDSQ), a type of incompletely condensed silsesquioxane, has been used as a molecular precursor for synthesizing new organotin discrete and oligomeric compounds. The equimolar reaction between DDSQ tetrasilanol (DDSQ-4OH) and Ph 2 SnCl 2 in the presence of triethylamine leads to obtaining discrete [Ph 4 Sn 2 O 4 (DDSQ)(THF) 2 ] (1). The change of sterically bulky aryl Ph 2 SnCl 2 precursor to linear alkyl n Bu 2 SnCl 2 led to the isolation of oligomeric [ n Bu 4 Sn 2 O 4 (DDSQ)] (2). The structures of compounds 1 and 2 have been demonstrated using single-crystal X-ray diffraction measurements. Indeed, the formation of oligomeric organotin DDSQ compound (2) was determined using GPC and MALDI-TOF mass spectroscopy. In compound 1, the geometry of the tin atom is fivecoordinated trigonal bipyramidal by two phenyl groups, two Si-O from DDSQ and one tetrahydrofuran. Compound 2 contains four coordinated two peripheral tin atoms and two five-coordinated central tin atoms, in which, the fifth coordinating oxo groups in the central tin atoms create the bridge between two different DDSQ units that leads to the formation of oligomeric structure. Density functional theory calculations on organotin DDSQs infer that the obtained lattice energy for compound 1 is far higher than for the case of compound 2, which indicates that the crystal of compound 1 is better stabilized in its crystal lattice with stronger close packing via intermolecular interactions between discrete molecules with coordinated THF compared to the crystal of compound 2. The greater stability arises mainly due to the sterically bulkier phenyl groups attached to the tin centers in compound 1, which provide accessibility for accommodating the THF molecule per tin via Sn-THF bonding, while contrarily the smaller n-butyl groups aid the polymerization of the four repeating units of [SnSi 4 O 7 ] or two Sn 2 O 4 (DDSQ) through m-oxo groups. Both compounds 1 and 2 were chosen to be promising precursors for the synthesis of ceramic tin silicates. The thermolysis of 2 at 1000 1C afforded the mixture of crystalline SnSiO 4 and SiO 2 but the same mixture was only formed by thermolysis of 1 at relatively higher temperature (1500 1C), which infers that compound 1 is more stable than compound 2 that is in good synergy with theoretical lattice energy.
Structural Studies of Bis-Catecholate, Bis-Dithiocatecholate, and Tetraalkoxy Diborane(4) Compounds
Inorganic Chemistry, 1998
CH 2 O) 2 (6). All the compounds adopt structures in the solid-state in which the B 2 O 4 or B 2 S 4 units are planar or very nearly so. In compounds 2 and 3, the dihedral angles between the two BO 2 C 2 planes are 17.3 and 31.8°respectively whereas in 1, 4 and 5 these angles are exactly 0°. In 6, a 3-fold disorder precluded our obtaining accurate positions for the two boron atoms, yet a dihedral angle of 0°is required by the 3 h site symmetry. The structure of the bis(Lewis base) adduct of B 2 Cl 4 , [B 2 Cl 4 (NHMe 2 ) 2 ] , is also described and structures of the salt [NH 2 Me 2 ][B(1,2-O 2 C 6 H 4 ) 2 ] (8) and the NMe 2 -bridged dimer [{BCl 2 (µ-NMe 2 )} 2 ] (9) are available in the Supporting Information. Compound 1 crystallized in the monoclinic space group P2 1 /c with a ) 4.746(1) Å, b ) 16.427(3) Å, c ) 7.053(2) Å, ) 98.59(2)°, and Z ) 2. Crystals of 2 were monoclinic, space group P2 1 /c with a ) 6.847(1) Å, b ) 18.871(5) Å, c ) 15.270(2) Å, ) 93.16(2)°, and Z ) 4. Crystals of 3 were triclinic, space group P1 h with a ) 9.478(4) Å, b ) 10.355(4) Å, c ) 15.082(7) Å, R ) 105.71(3)°, ) 100.31(4)°, γ ) 94.58(3)°, and Z ) 2. Crystals of 4 were monoclinic, space group P2 1 /c with a ) 15.364(3) Å, b ) 4.0502(4) Å, c ) 21.532(3) Å, ) 99.320(7)°, and Z ) 4. Crystals of 5 were monoclinic, space group P2 1 /c with a ) 6.0458(9) Å, b ) 7.5319(11) Å, c ) 16.552(2) Å, ) 96.291(3)°and Z ) 2. Compound 6 crystallized in the rhombohedral space group R3 hm with a ) 8.876(2) Å, c ) 13.821(3) Å and Z ) 3. Crystals of 7 were monoclinic, space group P2 1 /c with a ) 11.831(3) Å, b ) 19.458(5) Å, c ) 14.823(5) Å, ) 96.63-(4)°, and Z ) 12. S0020-1669(98)00431-5 CCC: $15.00
CCDC 1505509: Experimental Crystal Structure Determination
2017
Related Article: Kirill V. Zaitsev, Kevin Lam, Zhaisan Zhanabil, Yerlan Suleimen, Anastasia V. Kharcheva, Viktor A. Tafeenko, Yuri F. Oprunenko, Oleg Kh. Poleshchuk, Elmira Kh. Lermontova, and Andrei V. Churakov|2017|Organometallics|36|298|doi:10.1021/acs.organomet.6b00767
Chemistry and Modern Techniques of Characterization of Co-Crystals
IntechOpen eBooks, 2022
Co-crystals are multicomponent molecular materials held together through non-covalent interactions that have recently attracted the attention of supramolecular scientists. They are the monophasic homogeneous materials where a naturally occurring pharmaceutical active ingredient (API) and a pharmaceutically acceptable co-crystal former are bonded together in a 1:1 via non-covalent forces such as H-bonds, π-π, and van der Waals forces. Co-crystallization is a promising research field, especially for the pharmaceutical industry, due to the enormous potential of improved solubility and bioavailability. Co-crystals are not the only multicomponent molecular materials, as there are many other forms of multicomponent molecular solids such as salts, hydrates, solvates, and eutectics. The formation of co-crystals can roughly be predicted by the value of ∆pK a , that is, if the ∆pK a is more than 3, then this monophasic homogeneous material usually falls in the category of salts, whereas if the ∆pK a is less than 2, then co-crystals are usually observed. A number of methods are available for the co-crystal formation, broadly classified into two classes established on state of formation, that is, solution-based and solid-based co-crystal formation. Similarly, a number of techniques are available for the characterization of co-crystals such as Fourier transforms-infrared spectroscopy, single-crystal and powder X-ray diffraction, etc. In this chapter, we will discuss the available methods for co-crystallization and its characterization.
CCDC 145200: Experimental Crystal Structure Determination
2000
An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
CCDC 1509229: Experimental Crystal Structure Determination
2016
An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Zeitschrift für Kristallographie - New Crystal Structures, 2000
C 81H75N17O2.50Tb, orthorhombic, Pna21 (no. 33), a = 25.296(2) Å, b = 25.021(2) Å, c = 11.510(1) Å, V = 7285.0 Å 3 , Z = 4, Rgt(F) = 0.052, wRref(F 2 ) = 0.149, T = 153 K. C81H74DyN17O2, orthorhombic, Pna21 (no. 33), a = 25.216(2) Å, b = 25.039(2) Å, c = 11.4858(7) Å, V = 7252.0 Å 3 , Z = 4, Rgt(F) = 0.052, wRref(F 2 ) = 0.090, T = 153 K.
CCDC 1509228: Experimental Crystal Structure Determination
2016
An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
X-Ray Diffraction Crystallography
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