Interactions in Polymorphic Crystals ofm-Nitrophenol as Studied by Variable-Temperature X-ray Diffraction and Quantum Chemical Calculations

2006 ◽  
Vol 6 (1) ◽  
pp. 274-282 ◽  
Author(s):  
Grażyna Wójcik ◽  
Jolanta Holband ◽  
Jarosław J. Szymczak ◽  
Szczepan Roszak ◽  
Jerzy Leszczynski
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polymorphic Crystals

scholarly journals Synthesis of Bis(Carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 (n = 0, 1) and Attempt of Synthesis of Gadolinium Bis(Dicarbollide)

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1321
Author(s):  
Yasunobu Asawa ◽  
Aleksandra V. Arsent’eva ◽  
Sergey A. Anufriev ◽  
Alexei A. Anisimov ◽  
Kyrill Yu. Suponitsky ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
X Ray Diffraction ◽  
Stable Conformation ◽  
Acyl Chlorides ◽  
X Ray ◽  
Cesium Fluoride ◽  
The Stability

Bis(carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 (n = 0, 1) were prepared by the reactions of the corresponding carboranyl acyl chlorides with ethylenediamine. Crystal molecular structure of 1,1′-μ-(CH2NH(O)C-1,2-C2B10H11)2 was determined by single crystal X-ray diffraction. Treatment of bis(carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 with ammonium or cesium fluoride results in partial deboronation of the ortho-carborane cages to the nido-carborane ones with formation of [7,7′(8′)-μ-(CH2NH(O)C(CH2)n-7,8-C2B9H11)2]2−. The attempted reaction of [7,7′(8′)-μ-(CH2NH(O)CCH2-7,8-C2B9H11)2]2− with GdCl3 in 1,2-dimethoxy- ethane did not give the expected metallacarborane. The stability of different conformations of Gd-containing metallacarboranes has been estimated by quantum-chemical calculations using [3,3-μ-DME-3,3′-Gd(1,2-C2B9H11)2]− as a model. It was found that in the most stable conformation the CH groups of the dicarbollide ligands are in anti,anti-orientation with respect to the DME ligand, while any rotation of the dicarbollide ligand reduces the stability of the system. This makes it possible to rationalize the design of carborane ligands for the synthesis of gadolinium metallacarboranes on their base.

Synthesis and Molecular Structures of 2-Trimethylsilyl-, 2-Trimethylgermyl-, and 2-Trimethylstannyl-pyridines

1999 ◽  
Vol 54 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Frank Riedmiller ◽  
Alexander Jockisch ◽  
Hubert Schmidbaur
Keyword(s):  
Quantum Chemical ◽  
Crystal And Molecular Structure ◽  
Variable Temperature ◽  
Intrinsic Property ◽  
Molecular Structures ◽  
Grignard Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrogen Heteroatom

5-Methyl-2-trimethylsilyl-pyridine (1) has recently been prepared via the “in situ” Grignard reaction of 1-bromo-5-methyl-pyridine with magnesium and trimethylchlorosilane in refluxing tetrahydrofuran (thf) and structurally characterized. 2-Trimethylgermyl- (2) and 2- trimethylstannyl-pyridine (3) were now obtained from 2-bromo-pyridine through metallation (with n-BuLi) and treatment of the intermediates with Me3GeBr and Me3SnCl, respectively, in diethylether/ thf at -70°C. The crystal and molecular structure of compound 2 has been determined by low temperature (in situ) single crystal X-ray diffraction methods. There is a significant bending of the Me3Ge substituent towards the nitrogen heteroatom [Ge-C-N = 114.7(2)°]. This phenomenon is known from previous studies of the silicon analogue 1 to be not due to intramolecular (peripheral) Si/Ge←N coordination, but to be rather an intrinsic property of the heteroarene skeleton, as also confirmed by quantum-chemical calculations. Furthermore, there is no evidence for intermolecular coordination in the crystals. Such interactions could also be ruled out for the solution state of 2 and 3 through variable temperature multinuclear NMR investigations.

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