electronic reprint Crystal Structure Communications 2-(4-Hydroxyphenyl)-4,4-dimethyl-2-oxazoline: X-ray and density functional theory study 2-(4-Hydroxyphenyl)-4,4-dimethyl- 2-oxazoline: X-ray and density functional theory study (original) (raw)
Related papers
2-(4-Hydroxyphenyl)-4,4-dimethyl-2-oxazoline: X-ray and density functional theory study
Acta crystallographica. Section C, Crystal structure communications, 2006
In the crystal structure of the title compound, C(11)H(13)NO(2), there are strong intermolecular O-H...N hydrogen bonds which, together with weak intramolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules, held together by weak intermolecular C-H...O hydrogen bonds. A theoretical investigation of the hydrogen bonding, based on density functional theory (DFT) employing periodic boundary conditions, is in agreement with the experimental data. The cluster approach shows that the influence of the crystal field and of hydrogen-bond formation are responsible for the deformation of the 2-oxazoline ring, which is not planar and adopts a (4)T(3) ((C3)T(C2)) conformation.
Acta crystallographica. Section C, Crystal structure communications, 2005
Crystal structures are reported for three isomeric compounds, namely 2-(2-hydroxyphenyl)-2-oxazoline, (I), 2-(3-hydroxyphenyl)-2-oxazoline, (II), and 2-(4-hydroxyphenyl)-2-oxazoline, (III), all C9H9NO2 [systematic names: 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (I), 3-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (II), and 4-(4,5-dihydro-1,3-oxazol-2-yl)phenol, (III)]. In these compounds, the deviation from coplanarity of the oxazoline and benzene rings is dependent on the position of the hydroxy group on the benzene ring. The coplanar arrangement in (I) is stabilized by a strong intramolecular O-H...N hydrogen bond. Surprisingly, the 2-oxazoline ring in molecule B of (II) adopts a 3T4 (C2TC3) conformation, while the 2-oxazoline ring in molecule A, as well as that in (I) and (III), is nearly planar, as expected. Tetramers of molecules of (II) are formed and they are bound together via weak C-H...N hydrogen bonds. In (III), strong intermolecular O-H...N hydrogen bonds and weak intramolecular C-...
4,4-Bis(hydroxymethyl)-2-phenyl-2-oxazoline
Molbank
The title compound, 4,4-bis(hydroxymethyl)-2-phenyl-2-oxazoline 2, a well-known substance, was resynthesized in high yields through a conventional method. The structure of compound 2 was characterized for the first time by a single-crystal X-ray structure determination. The compound was further established through NMR spectroscopy (1D and 2D). In the molecular packing, two molecules of 4,4-bis(hydroxymethyl)-2-phenyl-2-oxazoline interact through H-Bonds to define “dimers” in which phenyl groups interact especially using π…π contact.
2-(2-Oxazolin-2-yl)benzene-1,4-diol: X-ray and density functional theory studies
Acta crystallographica. Section C, Crystal structure communications, 2007
In the crystal structure of the title compound, C(9)H(9)NO(3), there are strong intramolecular O-H...N and intermolecular O-H...O hydrogen bonds which, together with weak intermolecular C-H...O hydrogen bonds, lead to the formation of infinite chains of molecules. The calculated intermolecular hydrogen-bond energies are -11.3 and -2.7 kJ mol(-1), respectively, showing the dominant role of the O-H...O hydrogen bonding. A natural bond orbital analysis revealed the electron contribution of the lone pairs of the oxazoline N and O atoms, and of the two hydroxy O atoms, to the order of the relevant bonds.
Organic & Biomolecular Chemistry, 2013
A synthetic, structural and theoretical investigation into the solid-state, solution and gas phase structure(s) of six 2-acylmethyl-4,4-dimethyl-2-oxazolines is reported. Four of these materials, viz. α-[(4,5-dihydro-4,4dimethyl-2-oxazolyl)methylene]benzenemethanol (3a), α-[(4,5-dihydro-4,4-dimethyl-2-oxazolyl)-methylene]-(4-nitrobenzene)methanol (3b), 1-(4,5-dihydro-4,4-dimethyl-2-oxazolyl)-3,3-dimethyl-1-buten-2-ol (3d) and (E)-1-phenyl-2-((3aR)-3,3a,8,8a-tetrahydro-2H-indeno[1,2-d]oxazol-2-ylidene)ethanone (3f) have been characterised in the solid-state by single crystal X-ray diffraction studies. These data represent the first solid-state structural studies of this class of compounds and details the first synthesis and full characterisation of chiral derivative 3f. All four of these materials are shown to exist in the solid phase in the enamine tautomeric form (e.g., 3a is best described as 2-[4,4-dimethyl-2-oxazolidinylidene]-1-phenylethanone) and it is suggested (NMR, IR) that this isomeric form is likely also retained in solution (e.g., CDCl 3) as the more stable isomer. An investigation of the relative gas phase stabilities of the three possible (i.e., the (Z)-enol, keto and enamine) isomers of all five compounds by DFT at the B3LYP/6-311G(d) level of theory confirms the latter as the most stable form. The energy differences between the enamine and keto tautomers have been calculated to be the lowest for derivative 3d. These results are compared and contrasted with the previously reported NMR studies of such compounds which have identified the keto form as being a minor (albeit solution) tautomer. Equilibrium solution tautomer distributions for 3d are found to be solvent dependent. The protonated form of 3a, isolated as the HSO 4 − salt (i.e. 4a), has been further characterised in the solid state by single crystal X-ray diffraction. These data represent the first example of a protonated oxazoline to be structurally elucidated and confirms that upon protonation, the keto (oxazoline) tautomer is the energetically favoured form in the solid-state. This observation is further supported by DFT studies for the gas phase protonated forms of such materials. Further DFT (B3LYP/6-311G(d)) calculations employing the SM8 or SMD solvation models were then applied to address the observed solution isomeric distribution for 3d; these results corroborate the gas phase theoretical treatment and also yield values that predict the higher solution stability of the enamine form as observed, although they fail to account for the existence of the keto form as a minor solution state tautomer. To access the availability of an enol-form, via hypothetical de-protonation to the enolate, compound 3a was treated with hydrated Cu(NO 3) 2 in EtOH solution. The resulting isolated green-coloured product (5), the first metal derivative of this entire class of ligands, is best described (IR, X-ray diffraction)
Preparation and addition polymerization of substituted 2-oxazolines
Journal of Polymer Science: Polymer Chemistry Edition, 1975
The new oxazoline-containing monomers, 4-acrylyloxymethyl-2,4-dimethyl-2-oxazoline (AOMO), 4-methacrylyloxymethyl-2,4-dimethyl-2-oxazoline (MAOMO), 4-methacrylyloxymethyl-2-phenyl-4-methyl-2-oxazoline (PMAOMO), and the previously known monomer, 2-isopropenyl-4,4-dimethy1-2-oxazoline (IPRO), were synthesized for addition polymerization studies. The monomers were homopolymerized in benzene using a free radical initiator and in aqueous media using emulsion techniques. Molecular weights of 8,000-15,OOO @fwJ were obtained for the homopolymers. Copolymerization studies were carried out with AOMO, MAOMO, and IPRO as MI, and methyl methacrylate (MMA), methyl acrylate (MA), styrene (STY), acrylonitrile (AN), and vinyl acetate (VA) as Mz for each case of MI. Relative reactivity ratios for the fifteen copolymers and Q and e values for the three oxazoline monomers were determined. The rl values for AOMO and MAOMO copolymerizations indicated a lower value of k l l than expected, presumably because of steric effects. The rl values in the IPRO copolymerizations were somewhat larger than expected. It was proposed that significant electron donation to the radical center of IPRO-by resonance effects occurred.
Crystal structure of 5-benzoyl-2-(2-chlorophenyl)-4-phenyl-2-oxazoline, C22H16ClNO2
Zeitschrift für Kristallographie - New Crystal Structures, 2008
C 22 H 16 ClNO 2 ,monoclinic, P12 1 /n1(no. 14), a =10.6113(7) Å, b =9.6680(6) Å, c =17.176(1) Å, b =92.910(1)°, V =1759.8 Å 3 , Z =4,Rgt(F) =0.045, wRref(F 2 ) =0.111, T =100 K.
2015
The single crystal X-ray analysis of the ester-functionalized 2-oxazoline, methyl 3-(4,5-dihydrooxazol-2-yl)propanoate, revealed π-electron delocalization along the N-CO segment in the 2-oxazoline pentacycle to significant extent, which is comparable to its counterpart along the O-CO segment in the ester. Quantum chemical calculations based on the experimental X-ray geometry of the molecule supported the conjecture that the N-CO segment has a delocalized electronic structure similar to an ester group. The calculated bond orders were 1.97 and 1.10 for the N=C and CO bonds, and the computed partial charges for the nitrogen and oxygen atoms of´0.43 and´0.44 were almost identical. In the ester group, the bond orders were 1.94 and 1.18 for the CO bonds, while the partial charges of the oxygen atom are´0.49 and´0.41, which demonstrates the similar electronic structure of the N-CO and O-CO segments. In 2-oxazolines, despite the higher electronegativity of the oxygen atom (compared to the nitrogen atom), the charges of the hetero atoms oxygen and nitrogen are equalized due to the delocalization, and it also means that a cationic attack on the nitrogen is possible, enabling regioselectivity during the initiation of the cationic ring-opening polymerization of 2-oxazoline monomers, which is a prerequisite for the synthesis of materials with well-defined structures. Keywords: 2-oxazoline monomers; π-electron delocalization; regioselectivity of the initiation of cationic ring-opening polymerizations; ester-functionalized 2-oxazoline; hydrolysis of 2-oxazoline; methyl 3-(4,5-dihydrooxazol-2-yl)propanoate Materials 2015, 8 2 oxygen atom are −0.49 and −0.41, which demonstrates the similar electronic structure of the N-CO and O-CO segments. In 2-oxazolines, despite the higher electronegativity of the oxygen atom (compared to the nitrogen atom), the charges of the hetero atoms oxygen and nitrogen are equalized due to the delocalization, and it also means that a cationic attack on the nitrogen is possible, enabling regioselectivity during the initiation of the cationic ring-opening polymerization of 2-oxazoline monomers, which is a prerequisite for the synthesis of materials with well-defined structures.
Materials, 2015
The single crystal X-ray analysis of the ester-functionalized 2-oxazoline, methyl 3-(4,5-dihydrooxazol-2-yl)propanoate, revealed π-electron delocalization along the N-CO segment in the 2-oxazoline pentacycle to significant extent, which is comparable to its counterpart along the O-CO segment in the ester. Quantum chemical calculations based on the experimental X-ray geometry of the molecule supported the conjecture that the N-CO segment has a delocalized electronic structure similar to an ester group. The calculated bond orders were 1.97 and 1.10 for the N=C and CO bonds, and the computed partial charges for the nitrogen and oxygen atoms of´0.43 and´0.44 were almost identical. In the ester group, the bond orders were 1.94 and 1.18 for the CO bonds, while the partial charges of the oxygen atom are´0.49 and´0.41, which demonstrates the similar electronic structure of the N-CO and O-CO segments. In 2-oxazolines, despite the higher electronegativity of the oxygen atom (compared to the nitrogen atom), the charges of the hetero atoms oxygen and nitrogen are equalized due to the delocalization, and it also means that a cationic attack on the nitrogen is possible, enabling regioselectivity during the initiation of the cationic ring-opening polymerization of 2-oxazoline monomers, which is a prerequisite for the synthesis of materials with well-defined structures. Keywords: 2-oxazoline monomers; π-electron delocalization; regioselectivity of the initiation of cationic ring-opening polymerizations; ester-functionalized 2-oxazoline; hydrolysis of 2-oxazoline; methyl 3-(4,5-dihydrooxazol-2-yl)propanoate Materials 2015, 8 2 oxygen atom are −0.49 and −0.41, which demonstrates the similar electronic structure of the N-CO and O-CO segments. In 2-oxazolines, despite the higher electronegativity of the oxygen atom (compared to the nitrogen atom), the charges of the hetero atoms oxygen and nitrogen are equalized due to the delocalization, and it also means that a cationic attack on the nitrogen is possible, enabling regioselectivity during the initiation of the cationic ring-opening polymerization of 2-oxazoline monomers, which is a prerequisite for the synthesis of materials with well-defined structures.