1,6-Interactions between dimethylamino and aldehyde groups in two biphenyl derivatives

The title compounds, 2-(dimethylamino)biphenyl-2'-carboxaldehyde, C15H15NO, and 2-(dimethylamino)biphenyl-2',6'-dicarboxaldehyde, C16H15NO2, show similar 1,6-interactions [N...C=O 2.929 (3) to 3.029 (3) Å] between the dimethylamino and aldehyde groups located in the ortho positions of the two rings, which lie at 58.1 (1)-62.4 (1)° to each other

Kinetics of HO2 abstraction of H atoms from hydrocarbons and thermochemical properties of urethane monomers and radicals

SECTION I: Kinetics of HO2 Abstraction of H Atoms From Hydrocarbons Structures, internal rotational barriers and ideal gas thermochemical properties, ΔH°f98 for representative series of transition states for abstraction of H atoms from primary, secondary and tertiary hydrocarbons by the HO2 radical, TC-HOOH (1), TCC-HOOH (2), TC2C-HOOH (3), TC3C-HOOH (4), TC2CC-HOOH (5), TC2CC-HOOHC (6) and TC3CCC-HOOH (7) are analyzed in this study. Molecular structures and vibrational frequencies are determined at the B3LYP/6-3111G(d,p) density functional level. The S°298 and Cp(T) values (300≤T/K≤1500) from vibrational, translational, and external rotational contributions are calculated using statistical mechanics based on the vibrational frequencies and structures obtained from the density functional study. Internal rotor contributions are included in the S and CP(T) values. ΔHt°,TS of the transition states are computed at the G3MP2 level. The forward and reverse rate constants are calculated for the transition state reactions (1) to (7). ΔHrxn of these paths are estimated. ΔHt°,TS of species 1, 2, 3, 4 and 5 are also calculated at CBS-Q//B3LYP/6-311G(d,p) level and compared with the G3MP2 results. SECTION II: Thermochemical Properties, Enthalpy, Entropy and Heat Capacity (T) for Model Urethane Monomers and Corresponding Radicals. Two separate model urethanes (carbamates), Ethyl N Ethyl carbamate [C-C-N-C(O)-OC-C] and N (n-propyl) methylcarbamate [C-C-C-N-C(O)-O-C] are utilized to investigate the thermochemical properties and bond energies in several model urethane monomers. Molecular structure, vibration frequencies, energies, enthalpies (ΔH°f(298)) and bond energies are determined for the molecules and radicals at the B3LYP/6-31 G(d,p) Density Functional Calculation Level. Entropy (SΔ(298)) and heat capacity CP(T) are determined from the above structures and vibration frequencies. Enthalpies of formation (ΔfH°f(298)) are estimated using total energies including zero point vibrational energy (ZPVE), thermal contributions for each species and the calculated ΔHrxn from isodesmic- working reactions. Bond energies are also calculated. The enthalpy values calculated at the B3LYP/6-31 G(d,p) level for C-C-N-C(O)-O-C-C and C-C-C-N-C(O)-O-C are -115.08 and -113.34 kcal/mol, respectively. Carbon and nitrogen - hydrogen bond energies, calculated in this study are: 453.2 (kJ.mol) for C-C-Nj-C(O)-O-C-C, 400.3 (kJ.mol) for C-Cj-N-C(O)-O-C-C, 430.1 (kJ.mol) for C-C-N-C(O)-O-C-C, 429.4 (kJ.mol) for C-C-NC(O)-O-Cj-C, 439.9 (kJ.mol) for C-C-N-C(O)-O-C-C~, 452.7 (kJ.mol) for C-C-C-NiC(O)-O-C, 401.7 (kJ.mol) for C-C-Cj-N-C(O)-O-C, where j represents the radical site

C-N, C-O and C-S Ullmann-Type Coupling Reactions of Arenediazonium o-Benzenedisulfonimides

Arenediazonium o-benzenedisulfonimides have been used as efficient electrophilic partners in Cu(I) catalysed Ullmann-type coupling. The synthetic protocols are mild and easy, and produced either N-alkylanilines, aryl ethers, or thioethers in fairly good yields (18 positive examples, average yield 66%). o-Benzenedisulfonimide was recovered at the end of the reactions and was reused to prepare the starting salts for further reactions. It is noteworthy that diazonium salts have been used as electrophilic partners in the Ullmann-type protocol for the first time

(2,9-Dieth­oxy-1,10-phenanthroline-κ2 N,N′)bis­(thio­cyanato-κN)cobalt(II)

In the title complex, [Co(NCS)2(C16H16N2O2)], the CoII ion is coordinated by two N atoms from one 2,9-dieth­oxy-1,10-phenanthroline ligand and two N atoms from two different thio­cyanate ligands in a distorted tetra­hedral environment. The Co—N bonds involving the thio­cyanate ligands are significantly shorter than the other two Co—N bonds. The atoms of one of the eth­oxy groups are essentially coplanar with the phenanthroline ring [N=C—O—C = 178.8 (4)°], while the other eth­oxy group is slightly twisted from the phenanthroline ring plane [N=C—O—C = 167.2 (4)°]. In the crystal structure, there is a weak π–π stacking inter­action between two symmetry-related phenanthroline rings with a centroid–centroid distance of 3.706 (4) Å

1,5-Bis[(2-meth­oxy­eth­oxy)meth­yl]-1,5-naphthyridine-4,8(1H,5H)-dione

The complete mol­ecule of the title compound, C16H22N2O6, is generated by crystallographic inversion symmetry. The conformation of the N—C—O—C fragment of the side chain is approximately gauche [torsion angle = −74.84 (17)°]. In the crystal, weak C—H⋯O inter­actions link the mol­ecules

1-(4,5,6,7-Tetra­hydro­thieno[3,2-c]pyridin-5-yl)-2-{4-[3-(trifluoro­meth­yl)phen­yl]piperazin-1-yl}ethanone

In the title mol­ecule, C20H22F3N3OS, the piperazine ring has a chair conformation, and the N—C(=O)—C—N torsion angle is −59.42 (14)°. In the crystal, weak C—H⋯O and C—H⋯π inter­actions link the mol­ecules into layers parallel to (101)

N-(2,3,4-Trifluoro­phen­yl)morpholine-4-carboxamide

In title mol­ecule, C11H11F3N2O2, the central –N—C(=O)—N– unit is essentially planar [maximum deviation = 0.013 (2) Å] and forms a dihedral angle of 57.33 (9)° with the benzene ring. The morpholine ring is in a chair conformation. In the crystal, mol­ecules are linked into chains along [001] by N—H⋯O hydrogen bonds

4-Chloro-N-o-tolyl­benzamide

In the mol­ecule of the title compound, C14H12ClNO, the two benzene rings are close to coplanar [dihedral angle = 7.85 (4)°]. The amide N—C=O plane makes dihedral angles of 34.04 (4) and 39.90 (3)°, respectively, with the 4-chloro- and 2-methyl­phenyl rings. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains