A structural and carbon-nitrogen bond rotation study of N,N,N',N',2,2-hexamethylpropanediamide

1983 ◽  
Vol 36 (9) ◽  
pp. 1865 ◽  
Author(s):  
SF Lincoln ◽  
AM Hounslow ◽  
NJ Maeji ◽  
TW Hambley ◽  
MR Snow ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Kinetic Parameters ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Rotation ◽  
Nitrogen Bonds ◽  
Rotation Study ◽  
Nitrogen Bond

The molecular structure of N,N,N',N',2,2-hexamethylpropanediamide has been determined in the solid state by X-ray diffraction methods. The structure of Me2NCOCMe2CONMe2 may be broadly described as two planar Me2NCO entities intersecting at the tetrahedral -CMe2- site. The angle between the normals to the two Me2NCO planes is 104.6�, and the two oxygen atoms are disposed outwards from the molecule and away from each other. Proton (270-MHz) n.m.r. studies yield k(320 K) 32.0 � 3.2 s-1, ΔH‡ 69.5 � 0.4 kJ mol-1 and ΔS‡ 0.6 � 1.1 J K-1 mol-1 for rotation of the N-methyl groups about the carbon-nitrogen bonds in CD3NO2 solution. Similar magnitudes for the kinetic parameters characterizing this process are obtained in CDCl3, and CD3CN solutions.

A structural, solvent exchange and spin equilibrium study of (N,N-dimethylformamide)(R,S,R,S)-(1,4,8,11-tetramethyl-l,4,8,11- tetraazacyclotetradecane)nickel(II)

1984 ◽  
Vol 37 (4) ◽  
pp. 713 ◽  
Author(s):  
SF Lincoln ◽  
TW Hambley ◽  
DL Pisaniello ◽  
JH Coates
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Least Squares ◽  
Methyl Groups ◽  
Solvent Exchange ◽  
X Ray Diffraction ◽  
X Ray ◽  
Equilibrium Study ◽  
Trigonal Bipyramidal ◽  
Spin Species

The molecular structure of R,S,R,S-[Ni {(-N(Me)(CH2)2N(Me)(CH2)3-)2} (OCHNMe2)](SO3CF3)2 has been determined in the solid state by X-ray diffraction methods. The geometry about nickel(11) is midway between square based pyramidal and trigonal bipyramidal with OCHNMe2 occupying the axial or an equatorial site in these geometries respectively. The nickel(II) is displaced 0.29 � from the least-squares tetraaza plane on the same side as the four methyl groups and OCHNMe2. In OCHNMe2 solution the formation of this five-coordinate high-spin species by coordination of OCHNMe2 by its four-coordinate low-spin precursor is characterized by K(298.2 K) = 10 � 2, ∆H = -12.8 � 2.7 kJ mol-1 and ∆S = -24.1 � 9.O JK-l mol-1 as determined by spectrophotometry. 1H (300 MHz) n.m.r. studies show that kwx(298.2 K) = (1.6 � 0.2) × 107 s-1, ∆H‡ = 27.8 � 0.4 kJ mol-1 and ∆S‡ = -13.O � 2.0 JK-1 mol-1 characterize the exchange of OCHNMe2 on R,S,R,S-[Ni {(-N(Me)(CH2)2N(Me)(CH2)3-)2 }(OCHNMe2)]2+.

Molecular structure in the solid state (X-Ray diffraction) and in solution (1H and 13C NMR) of nifurtimox and two pyrazol-1-Yl analogs

2010 ◽  
Vol 97 (11-12) ◽  
pp. 1055-1066 ◽  
Author(s):  
Ma de la Concepción Foces-Foces ◽  
Félix Hernández Cano ◽  
Rosa Ma Claramunt ◽  
Alain Fruchier ◽  
José Elguero
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
13C Nmr ◽  
X Ray Diffraction ◽  
1H And 13C Nmr ◽  
X Ray

Structure of 2′,3′-dimethyl-3,5-diiodo-D,L-thyronine, a fixed-conformation analogue of the thyroid hormone 3,5,3′-triiodo-L -thyronine

1976 ◽  
Vol 54 (8) ◽  
pp. 1317-1321 ◽  
Author(s):  
J. Keith Fawcett ◽  
Norman Camerman ◽  
Arthur Camerman
Keyword(s):  
Molecular Structure ◽  
Thyroid Hormone ◽  
Diphenyl Ether ◽  
Three Dimensional ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fourier Techniques ◽  
Cell Dimensions ◽  
Biological Tests

The three-dimensional molecular structure of 2′,3′-dimethyl-3,5-diiodo-D,L-thyronine (2′,3′-DMT2) has been determined by X-ray diffraction in order to establish the conformational characteristics responsible for biological activity in thyroid hormone analogues. Crystals of 2′,3′-DMT2 hydrochoride hydrate are monoclinic with cell dimensions a = 29.76, b = 6.84, c = 24.09 Å, β = 91.4°, space group C2/c with Z = 8 molecules per cell. The structure was solved by Patterson and Fourier techniques and refined by least squares. The atoms comprising the alanine portion of the molecule are disordered but the conformation of the diphenyl ether rings is clear: the β-ring 2′-methyl and 3′-methyl groups are situated distal to the α-ring. Thus the conformation postulated for this compound in biological tests of fixed-conformation thyromimetics is now structurally supported.

Halogen Bonds in Two Silver(I) Mixed-ligand Supramolecular Frameworks: Synthesis, Structure and Photoluminescence

2011 ◽  
Vol 66 (10) ◽  
pp. 1035-1041 ◽  
Author(s):  
Di Sun ◽  
Rong-Bin Huang ◽  
Lan-Sun Zheng
Keyword(s):  
Solid State ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Mixed Ligand ◽  
Methyl Groups ◽  
Halogen Bonds ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Types

Two silver(I) tetrachlorophthalates incorporating aminopyrimidyl ligands, namely [Ag4(apym)4(tcpta)2]n (1) and [Ag2(dmapym)(tcpta)]n (2), (apym = 2-aminopyrimidine, dmapym = 2-amino-4,6-dimethylpyrimidine, H2tcpta = tetrachlorophthalic acid), were synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Both 1 and 2 form sheets which are assembled into 3D supramolecular frameworks via halogen bonds, hydrogen bonds and π...π interactions. Even adding two more methyl groups to the pyrimidyl ring does not change the dimensions of 1 and 2, but it influences the arrangement of the N- and O-donors in the solid state which in turn results in different types of halogen bonds. The photoluminescence properties of 1 and 2 were investigated in the solid state at room temperature.

Structure, properties and comparison of C,N-chelated and amido-stabilized plumbylenes

2010 ◽  
Vol 75 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Josef Bareš ◽  
Vítězslav Šourek ◽  
Zdeňka Padělková ◽  
Philippe Meunier ◽  
Nadine Pirio ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Crystalline Material ◽  
X Ray Diffraction ◽  
Single Crystalline ◽  
X Ray ◽  
Xrd Techniques ◽  
Structure Properties

The molecular structure of {2-[(CH3)2NCH2]C6H4}2Pb (1) in the solid state was determined by X-ray diffraction techniques on a single crystalline material. Bulky amido ligand stabilized complexes [(i-C3H7)2C6H3]NHLi (2) and [(i-C3H7)2C6H3N(Me3Si)]2Pb (3) were synthesized and characterized both in the solid state and solution by 1H, 13C, 15N and 207Pb NMR and XRD techniques. The structure of both C,N-chelated and bulky amido plumbylenes is compared.

Synthesis and solid-state molecular structures of bis- and mono-nitrosobenzene complexes of ruthenium porphyrins

2002 ◽  
Vol 80 (9) ◽  
pp. 1252-1258 ◽  
Author(s):  
Jonghyuk Lee ◽  
Brendan Twamley ◽  
George B Richter-Addo
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Ir Spectra ◽  
Single Crystal ◽  
Binding Mode ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Parallel Arrangement ◽  
Ruthenium Porphyrin

Bis-nitrosobenzene complexes of the form (por)Ru(PhNO)2 (por = TPP, TTP; TPP = tetraphenylporphyrinato dianion, TTP = tetratolylporphyrinato dianion) have been prepared in good yields from the reaction of the (por)Ru(CO) precursor with excess PhNO in dichloromethane. The IR spectra of the complexes (as KBr pellets) displayed new bands at ~1348 cm–1, due to υNO. The solid-state molecular structure of (TPP)Ru(PhNO)2 was determined by single-crystal X-ray diffraction, and revealed that the PhNO ligands are bound to the Ru center via the N-binding mode. Reactions of the (por)Ru(PhNO)2 complexes with excess 1-methylimidazole gave the mono-nitrosobenzene complexes (por)Ru(PhNO)(1-MeIm). The IR spectra revealed a lowering of υNO in these mononitrosobenzene derivatives by ~27 cm–1, a feature consistent with the replacement of one π-acid PhNO ligand with the more basic 1-MeIm ligand. The solid-state molecular structure of (TPP)Ru(PhNO)(1-MeIm) reveals, in addition to the N-binding of the PhNO ligand, an essentially parallel arrangement of the C-N-O (of PhNO) and imidazole planes; this is in contrast with the (TPP)Ru(PhNO)2 complex, in which the C-N-O planes (of PhNO) are essentially perpendicular.Key words: nitroso, X-ray, ruthenium, porphyrin, imidazole.

Étude structurale d'une imidazolylcétone l'isopropyl-1-phényl-2-diaza-1,3-one-6-bicyclo[3,3,0]octène-2

1990 ◽  
Vol 68 (12) ◽  
pp. 2192-2197
Author(s):  
Jean-Pierre Reboul ◽  
Pierre Brouant ◽  
Jacques Barbe ◽  
Claude Caranoni ◽  
Catherine Soula ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure In Solution ◽  
State Configuration

The solid state configuration of 1-isopropyl-2-phenyl-1,3-diaza-6-one-bicyclo[3.3.0]oct-2-ene was determined from X-ray diffraction data (a = 10.039(3) Å; b = 8.683(3) Å; c = 15.505(6) Å; β = 90.72(9)°; P21/c;R = 0.047). This structure is compared to those of three other related (Δ-2)-imidazolines. Molecular structure in solution was investigated by 1H nuclear magnetic resonance spectroscopy. Results clearly indicate that the title compound has the same structure in the solid state as in solution. On the contrary, this configuration differs appreciably from those of other (Δ-2)-imidazolines considered in this report. Keywords: (Δ-2)-imidazolines, crystal structure, NMR, conformations.

The solid-state molecular structure of W(NO)3Cl3 and the nature of its W—NO bonding

2004 ◽  
Vol 82 (2) ◽  
pp. 285-292 ◽  
Author(s):  
Trevor W Hayton ◽  
Brian O Patrick ◽  
Peter Legzdins ◽  
W Stephen McNeil
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Dft Calculations ◽  
Diffraction Analysis ◽  
Mirror Plane ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths ◽  
Complex Solutions

The monomeric trinitrosyl complex, W(NO)3Cl3, can be prepared by the treatment of WCl6 in CH2Cl2 with NO gas, and its identity has been unambiguously confirmed by a single-crystal X-ray diffraction analysis. The complex crystallizes in the space group Pmn21 as a three-component twin (a = 10.4280(4) Å, b = 6.3289(2) Å, c = 5.6854(2) Å, Z = 2, R1 = 0.065, wR2 = 0.176). Its solid-state molecular structure consists of a tungsten centre bound to three chloride ligands and three linear nitrosyl ligands in a fac-octahedral stereochemistry. In addition, the structure contains a crystallographically imposed mirror plane. The two independent W—N linkages are 1.88(2) and 1.92(1) Å long, while the two corresponding N—O bond lengths are 1.13(2) and 1.16(2) Å. DFT calculations on fac-W(NO)3Cl3 at the B3LYP/LANL2DZ level of theory afford optimized intramolecular metrical parameters that match the X-ray crystallographically determined bond lengths and bond angles quite well. In addition, they provide a rationale for the nearly linear W-N-O linkages extant in the complex. Solutions of fac-W(NO)3Cl3 in CH2Cl2 lose ClNO under ambient conditions and deposit the well-known [W(NO)2Cl2]n polymer, and this conversion is fully reversible.Key words: nitrosyl, tungsten, structure, bonding.

Synthesis, conformational analysis, and molecular structure of 5-ethyl-5,6-dihydro-11H-dibenzo[b,e]azepine-6-thione

1994 ◽  
Vol 72 (2) ◽  
pp. 334-338 ◽  
Author(s):  
J. Irurre ◽  
F. Marquillas ◽  
A. Alvarez-Larena ◽  
J.F. Piniella
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Conformational Analysis ◽  
Activation Barrier ◽  
Direct Methods ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

5-Ethyl-5,6-dihydro-11H-dibenzo[b,e]azepine-6-thione has been synthesized and studied in the solid state and in solution by X-ray diffraction and 1H DNMR, respectively. The crystals are monoclinic, P21/n, a = 9.642(1), b = 13.757(2), c = 9.889((2) Å, β = 98.57(1)°, Z = 4. The structure has been solved by direct methods and refined to an R value of 0.040 for 1771 reflections with I > 2.5σ(I). The seven-membered ring has a slightly deformed boat conformation. The activation barrier associated with the inversion ring has been determined, being ΔG≠ = 21.6 kcal/mol.

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