Nonplanar Ring Research Articles

(E)-4-[(4-Amino-5-bromopyridin-3-yl)iminomethyl]phenol

In the mol­ecule of the title compound, C12H10BrN3O, the pyridine and benzene rings are oriented at a dihedral angle of 34.93 (3)°. Intra­molecular N—H⋯N and N—H⋯Br hydrogen bonds result in the formation of two non-planar five-membered rings. In the crystal structure, inter­molecular O—H⋯N and N—H⋯O hydrogen bonds link the mol­ecules to form a three-dimensional network.

Mesaconitine

The title compound, (1α,3α,6α,14α,15α,16β)-3,8,13,14,15-penta­hydr­oxy-1,6,16-trimeth­oxy-4-methoxy­methyl-20-methyl­acon­itan-8,14-diyl 8-acetate 14-benzoate, C33H45NO11, a C19 diterpenoid alkaloid, obtained from the roots of Aconitum kusnezoffii, has been crystallographically characterized in this study. Rings A, B and E have chair conformations, rings C and F display envelope conformations, and ring D adopts a boat conformation. There are inter- and intra­molecular O—H⋯O hydrogen bonds, the latter resulting in the formation of a non-planar seven-membered ring. The inter­molecular inter­actions link the mol­ecules into a two-dimensional network.

Dichloridobis(5-m-tolyl-1,3,4-thiadiazol-2-ylamine-κN3)zinc(II)

In the mol­ecule of the title compound, [ZnCl2(C9H9N3S)2], the ZnII atom is four-coordinated by two N atoms from two 5-m-tolyl-1,3,4-thia­diazol-2-ylamine ligands and two Cl anions in a distorted tetra­hedral geometry. Intra­molecular N—H⋯N, N—H⋯Cl and C—H⋯S hydrogen bonds result in the formation of one planar and one non-planar five-membered, one non-planar six-membered and one non-planar seven-membered ring. The six- and seven-membered rings have twist conformations, while the non-planar five-membered ring adopts an envelope conformation with the S atom displaced by 0.541 (3) Å from the plane of the other ring atoms. The planar five-membered ring is oriented at dihedral angles of 1.74 (3) and 1.08 (3)°, respectively, with respect to the adjacent aromatic and thia­diazole rings. In the crystal structure, inter­molecular N—H⋯Cl hydrogen bonds link the mol­ecules into a three-dimensional network.

2-(2,4-Dichlorophenyl)-3-[5-(4-methoxyphenyl)-1,3,4-thiadiazol-2-yl]-1,3-thiazolidin-4-one

In the mol­ecule of the title compound, C18H13Cl2N3O2S2, the thia­zolidinone ring has an envelope conformation with the S atom displaced by 0.394 (3) Å from the plane of the other ring atoms. The thia­diazole ring is oriented at a dihedral angle of 7.40 (4)° with respect to the 4-methoxy­phenyl ring. Intra­molecular C—H⋯S, C—H⋯N and C—H⋯Cl hydrogen bonds result in the formation of two planar and two non-planar five-membered rings. The planar five-membered rings are oriented at a dihedral angle of 6.23 (3)°. The 2,4-dichloro­phenyl ring is oriented at dihedral angles of 84.21 (4) and 83.55 (3)° with respect to the thia­diazole and 4-methoxy­phenyl rings, respectively. In the crystal structure, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric dimers.

2-(3-Oxo-1,3-dihydroisobenzofuran-1-ylamino)benzoic acid

In the mol­ecule of the title compound, C15H11NO4, the essentially planar phthalide group is oriented at a dihedral angle of 56.78 (5)° with respect to the substituted aromatic ring. An intra­molecular N—H⋯O hydrogen bond results in the formation of a non-planar six-membered ring, which adopts a nearly flattened-boat conformation. In the crystal structure, inter­molecular C—H⋯O, O—H⋯O and N—H⋯O hydrogen bonds link the mol­ecules, generating centrosymmetric R 2 2(8) and R 2 2(11) ring motifs and forming a three-dimensional network.

(Glycol-κO,O')nitros-yl(η-penta-methyl-cyclo-penta-dien-yl)ruthenium(II) bis-(tri-fluoro-methane-sulfonate).

The title compound, [Ru(C10H15)(NO)(HOCH2CH2OH)](CF3SO3)2, possesses a three-legged piano-stool geometry around the Ru atom, with an average Ru—O distance of 2.120 (6) Å and an Ru—N—O angle of 159.45 (14)°. The ethyl­eneglycol ligand forms a non-planar metallacyclic ring by chelating the Ru atom via the O atoms. The O⋯O distances of 2.554 (2) and 2.568 (2) Å are indicative of hydrogen bonding between coordinated ethyl­eneglycol and outer-sphere trifluoro­methane­sulfonate fragments. The crystal packing is stabilized by ionic forces and several CH3⋯·F (2.585 and 2.640 Å) and CH3⋯O inter­actions (2.391, 2.678, 2.694 and 2.699 Å) between the penta­methyl­cyclo­penta­dienyl ligand and trifluoro­methane­sulfonate anion. There is noticeable short inter­molecular contact [2.9039 (16) Å], between an O atom of the SO3 group and a C atom of the penta­methyl­cyclo­penta­dienyl ligand.

Structure of CrIIF(NCMe)2BF4. Rietveld refinement of a component of a physical mixture of unknown composition

The reaction of CrII(NCMe)4(BF4)2 and [NBun4][TCNE] (TCNE = tetracyanoethylene) in CH2Cl2 forms a solid that is a mixture of an amorphous reduced-TCNE containing phase(s) and a crystalline component. Rietveld refinement of the high-resolution, synchrotron X-ray powder pattern enabled the determination of the structure of the crystalline phase to be of CrIIF(NCMe)2BF4 composition and illustrates that this methodology can be used to determine the structure of a crystalline substance of unknown composition in the presence of confounding information from coexisting amorphous material. CrIIF(NCMe)2BF4 exhibits a 1-D chain structure with both μ-F and μ-BF4− linkages that forms a nonplanar 6-membered FCrFBFCr ring. CrIIF(NCMe)2BF4 possesses a previously unknown structure type and is a potential source of CrIIF+ for synthesis applications.

2-Bromo-5-iodo-1,3-dimethylbenzene

In the mol­ecule of the title compound, C8H6BrI, the H atoms of methyl groups are disordered; site-occupation factors were fixed at 0.50. The non-H atoms all lie on a crystallographic mirror plane. Weak intra­molecular C—H⋯Br hydrogen bonds result in the formation of two non-planar five-membered rings.

Optical-axis perturbation in nonplanar ring resonators

Several findings on the optical-axis perturbation of nonplanar ring resonators have been obtained identical by utilizing the augmented 5×5 matrix formulation and augmented 6×6 matrix formulation, respectively. It has been found out that in the whole region of 0<L/R<2, the longer the mirror radius, the higher the sensitivity of optical-axis decentration, while the total cavity length is L and the radius of the curvature mirrors is R. The sensitivity of optical-axis tilt in the region of 0<L/R<2 has been carried out too. The optical-axis decentration and optical-axis tilt inside the region of L/R>2 have been discussed. The differences of the optical-axis perturbation between planar and nonplanar ring resonators have also been analyzed. These interesting findings are important to the cavity design of nonplanar ring resonators.

5-[3-(Dimethylamino)propyl]-5H-dibenzo[a,d]cycloheptan-5-ol

The title compound, C20H23NO, was synthesized by the reaction of dibenzo[a,d]cyclohepta-1,4,6-trien-5-one and dimethylaminopropylmagnesium. Intramolecular O—H...N hydrogen bonding causes the formation of a non-planar seven-membered ring. The benzene rings are oriented at a dihedral angle of 51.37 (3)°.

(Z)-5-(2-Fluorobenzylidene)-1,3-thiazolidine-2,4-dione

In the title compound, C10H6FNO2S, the benzene and thiazolidine rings are oriented at a dihedral angle of 8.90 (3)°. Intramolecular C—H...O, C—H...F and C—H...S hydrogen bonds result in the formation of two nearly planar five-membered rings and one non-planar six-membered ring, the five-membered rings being also nearly coplanar with the adjacent rings. In the crystal structure, intermolecular N—H...O and C—H...O hydrogen bonds link the molecules.

(Z)-5-(2-Chlorobenzylidene)thiazolidine-2,4-dione

In the title compound, C10H6ClNO2S, the benzene and thiazolidine rings are oriented at a dihedral angle of 14.22 (5)°. Intramolecular C—H...O, C—H...Cl and C—H...S hydrogen bonds result in the formation of two nearly planar five-membered rings and one nonplanar six-membered ring, the five-membered rings being also nearly coplanar with the adjacent rings. In the crystal structure, intermolecular N—H...O hydrogen bonds link the molecules.

8-Chloro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridine

The title compound, C14H12ClN, has a tricyclic fused-ring system composed of a benzene ring, a pyridine ring and a central nonplanar seven-membered ring.

2-[(1E,4E)-4-(2-Methoxyphenyl)-3H-benzo[b][1,5]diazepin-2-yl]phenol

The asymmetric unit of the title compound, C22H18N2O2, contains two crystallographically independent mol­ecules, in which each mol­ecule is composed of three planar six-membered rings and one nonplanar seven-membered ring. The six-membered A (phenol), B (fused benzene) and C (methoxyphenyl) rings are oriented with respect to each other at dihedral angles of 88.79 (3) (A/B), 68.16 (3) (A/C) and 37.51 (2)° (B/C), and 82.43 (3) (A′/B′), 78.52 (2) (A′/C′) and 28.65 (3)° (B′/C′). The seven-membered rings adopt near-boat conformations. Intra­molecular O—H⋯N and C—H⋯O hydrogen bonds are present in the crystal structure.

2-[(1E,4E)-2-(4-Methoxyphenyl)-3H-benzo[b][1,4]diazepin-4-yl]phenol

The title compound, C22H18N2O2, is a biologically active 1,5-benzodiazepine derivative, containing three planar six-membered rings and one nonplanar seven-membered ring. The six-membered rings A (phenol), B (fused benzene) and C (methoxyphenyl) are oriented with respect to each other at dihedral angles of 39.22 (2) (A/B), 87.31 (3) (A/C) and 54.42 (3)° (B/C). The seven-membered ring adopts a near-boat conformation. In the crystal structure, intra­molecular O—H⋯N and inter­molecular C—H⋯O hydrogen bonds are present.

Nonplanar ring resonator modes: generalized Gaussian beams

Several findings on the modes of a nonplanar ring resonator have been carried out by utilizing the matrix method of generalized Gaussian beams. The widely used nonplanar ring resonator--a four-equal-sided nonplanar ring cavity with two curvature mirrors and two planar mirrors--has been chosen as an example. The overall stability maps of this typical nonplanar ring cavity with L/R ranging from 0 to infinity are calculated and described, while the total cavity length is L and the radius of the curvature mirrors is R. The stability map has also been found to have asymmetry with total image rotation rho ranging from 0 degrees to 360 degrees and 0<L/R<2. It has also been found that there still exist several stable regions in the extended region with L/R>2. The Gaussian modes of the nonplanar ring cavity have been found to have different characteristics with different design parameters such as rho and L/R. The azimuth angles of the major and minor axes of the spot size have been found to be variable with different design parameters such as rho and L/R and variable under different location of the nonplanar cavity. These interesting findings are totally different from the behavior of conventional planar stable resonators and are important to the cavity designs of nonplanar ring resonators.

Spin Chemical Control of Photoinduced Electron-Transfer Processes in Ruthenium(II)-Trisbipyridine-Based Supramolecular Triads: 2. The Effect of Oxygen, Sulfur, and Selenium as Heteroatom in the Azine Donor

Nanosecond time-resolved absorption studies in a magnetic field ranging from 0 to 2.0 T have been performed on a series of covalently linked donor(PXZ)-Ru(bipyridine)3-acceptor(diquat) complexes (D-C2+-A2+). In the PXZ moiety, the heteroatom (X = O (oxygen), T (sulfur), and S (selenium)) is systematically varied to study spin-orbit coupling effects. On the nanosecond time scale, the first detectable photoinduced electron-transfer product after exciting the chromophore C2+ is the charge-separated (CS) state, D+-C2+-A+, where an electron of the PXZ moiety, D, has been transferred to the diquat moiety, A2+. The magnetic-field-dependent kinetic behavior of charge recombination (monoexponential at 0 T progressing to biexponential for all three complexes with increasing field) can be quantitatively modeled by the radical pair relaxation mechanism assuming creation of the CS state with pure triplet spin correlation (3CS). Magnetic-field-independent contributions to the rate constant kr of T+/- --> (T0,S) relaxation are about 4.5 x 10(5) s-1 for DCA-POZ and -PTZ (due to a vibrational mechanism) and 3.5 x 10(6) s-1 for DCA-PSZ (due to spin rotational mechanism). Recombination to the singlet ground state is allowed only from the 1CS spin level; spin-forbidden recombination from 3CS seems negligible even for DCA-PSZ. The field dependence of kr (field-dependent recombination) can be decomposed into the contributions of various relaxation mechanisms. For all compounds, the electron spin dipolar coupling relaxation mechanism dominates the field dependence of tau(slow) at fields up to about 100 mT. Spin relaxation due to the g-tensor anisotropy relaxation mechanism accounts for the field dependence of tau(slow) for DCA-PSZ at high fields. For the underlying stochastic process, a very short correlation time of 2 ps has to be assumed, which is tentatively assigned to a flapping motion of the central, nonplanar ring in PSZ. Finally, it has been confirmed by paramagnetic quenching (here Heisenberg exchange) experiments of the magnetic-field effects with TEMPO that all magnetic-field dependencies observed with the present DCA-PSZ systems are indeed due to the magnetic-field dependence of spin relaxation.

Di-μ-chlorido-bis{[(3,4-η)-2,5-dimethylhex-3-yne-2,5-diol]copper(I)}

The title compound, [Cu2Cl2(C8H14O2)2], exhibits a non-planar four-membered Cu2Cl2 ring, with one alkyne ligand coordinated to each Cu atom. Due to the presence of the Cl bridges as potential hydrogen-bond acceptor sites, one of the hydroxy substituents is engaged in an intra­molecular hydrogen bond, whereas the remaining three OH groups form inter­molecular inter­actions which sustain the supra­molecular structure.

Theoretical Investigation on Stability and Isomerizations of CH3SO Isomers

The stability and isomerizations of CH3SO isomers have been investigated at B3LYP/6-311G(d,p), MP2/6-311G(d,p), QCISD/6-311G(d,p), and CCSD(T)/6-311G(d,p) levels. Geometries of isomers and transition states (TS) have been optimized at the B3LYP/6-311G(d, p) level. Vibration analysis and the intrinsic reaction coordinate (IRC) calculated at the same level have been applied to validate the connection of the stationary points. The four different methods give similar results: 11 isomers and 9 isomerization channels were found. CH3SO and CH2(S)OH are the most stable species among the 11 isomers. Furthermore, the breakage and formation of the chemical bonds in isomerization reactions have been discussed by the topological analysis method of electronic density. The "energy transition state (ETS)" and the "structure transition state (STS)" of all the isomerizations have been found. The topological analysis shows that the relative positions of ETS and STS are determined by reaction energy. The nonplanar four-member ring structure transition state (STS), which was first found in this paper, extended the concept of ring STS.

Multi-end-pumped nonplanar ring laser with a two-mirror resonator and output from a single point

A multi-end-pumped nonplanar ring laser with a two-mirror resonator has been demonstrated. Two important parameters of the beam loops are described, and simulation diagrams of the beam loops are shown. Using an output coupler with a fan-shaped distribution in reflectivity, multi-end-pumped operation with the output beam from a single point has been achieved, and the experimental results show that the laser could be multi-end-pumped to reduce thermal effects and multiply the fracture limit of the laser crystal.