Polyoxometalate-like structure of new potassium triphenylsiloxides: [K6(OSiPh3)6(C3H7OH)(H2O)]·2C6H5CH3 and [K6(OSiPh3)6(H2O)2]

2021 ◽  
Vol 77 (9) ◽  
pp. 522-528
Author(s):  
Patrycja Wytrych ◽  
Józef Utko ◽  
Tadeusz Lis ◽  
Łukasz John

The synthesis and structural characterization of two new potassium triphenylsiloxides, namely, aqua(propan-2-ol)hexakis(triphenylsilanolato)hexapotassium toluene disolvate, [K6(C18H15OSi)6(C3H8O)(H2O)]·2C7H8, and diaquahexakis(triphenylsilanolato)hexapotassium, [K6(C18H15OSi)6(H2O)2], are reported. Both compounds crystallize in the triclinic space group P-1. The structure in each case resembles an alkali metal polyoxometalate-like structure, in which electrostatic interactions are observed in the metal–oxygen core. Furthermore, both compounds also resemble a reverse micelles-like architecture, in which the hydrophilic core is enclosed in a hydrophobic shell. The cores of the complexes are flanked by hydrophobic aromatic rings derived from Ph3SiO− anions, where intramolecular π-interactions between the aromatic rings and potassium cations stabilize the cores of the crystals. Moreover, in both structures, the presence of hydrogen bonds is observed; until now, no crystal structures have been described containing K atoms and triphenylsiloxide molecules in which the presence of hydrogen bonds was confirmed. Thus, these coordination entities could be considered as attractive reagents for further synthetic protocols towards heterometallic complexes.

2003 ◽  
Vol 59 (11) ◽  
pp. o622-o624 ◽  
Author(s):  
Bruce D. James ◽  
Siti Mutrofin ◽  
Brian W. Skelton ◽  
Allan H. White

Structural characterization of the title compound, C10H15N2 +·PF6 −, shows it to be ionic, with the pyridine rather than the piperidine N atom being protonated and forming hydrogen bonds to the counter-ions, resulting in two independent ion pairs. A number of unusual features are noted, in particular the remarkably close inter-ring hydrogen contacts [1.97 (3)–2.00 (3) Å] and the considerable differences in the pair of cations, in respect of the torsion angles within the piperidine ring involving the bonds to either side of the N atom.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Houda Marouani ◽  
Salem Slayyem Al-Deyab ◽  
Mohamed Rzaigui

Single crystals of [2-CH3CH2C6H4NH3]6P6O18⋅4H2O are synthesized in aqueous solution by the interaction of cyclohexaphosphoric acid and 2-ethylaniline. This compound crystallizes in the monoclinic system with P21/c space group the unit cell dimensions are: a=16.220(4) Å, b=10.220(5) Å, c=20.328(4) Å, β=113.24(3)∘, Z=2, and V=3096.5(18) Å3. The atomic arrangement can be described by layers formed by cyclohexaphosphate anions P6O186− and water molecules connected by hydrogen bonds O–H⋯O. These inorganic layers are developed around bc planes at x=1/2 and are interconnected by the H-bonds created by ammonium groups of organic cations. All the hydrogen bonds, the van der Waals contacts and electrostatic interactions between the different entities give rise to a three-dimensional network in the structure and add stability to this compound. The thermal behaviour and the IR spectroscopic studies of this new cyclohexaphosphate are discussed.


Author(s):  
Consiglia Tedesco ◽  
Eleonora Macedi ◽  
Alessandra Meli ◽  
Giovanni Pierri ◽  
Giorgio Della Sala ◽  
...  

The synthesis and the structural characterization of a cyclic hexapeptoid with four methoxyethyl and two propargyl side chains have disclosed the presence of a hydrate crystal form [form (I)] and an anhydrous crystal form [form (II)]. The relative amounts of form (I) and form (II) in the as-purified product were determined by Rietveld refinement and depend on the purification procedures. In crystal form (I), peptoid molecules assemble in a columnar arrangement by means of side-chain-to-backbone C=CH...OC hydrogen bonds. In the anhydrous crystal form (II), cyclopeptoid molecules form ribbons by means of backbone-to-backbone CH2...OC hydrogen bonds, thus mimicking β-sheet secondary structures in proteins. In both crystal forms side chains act as joints among the columns or the ribbons and contribute to the stability of the whole solid-state assembly. Water molecules in the hydrate crystal form (I) bridge columns of cyclic peptoid molecules, providing a more efficient packing.


2005 ◽  
Vol 117 (1) ◽  
pp. 70-74 ◽  
Author(s):  
Eva Hevia ◽  
Gordon W. Honeyman ◽  
Alan R. Kennedy ◽  
Robert E. Mulvey ◽  
David C. Sherrington

ChemInform ◽  
2010 ◽  
Vol 24 (4) ◽  
pp. no-no
Author(s):  
F. T. EDELMANN ◽  
F. PAUER ◽  
M. WEDLER ◽  
D. STALKE

1992 ◽  
Vol 31 (20) ◽  
pp. 4143-4146 ◽  
Author(s):  
Frank T. Edelmann ◽  
Frank Pauer ◽  
Michael Wedler ◽  
Dietmar Stalke

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