Transverse multi-mode effects on the performance of photon-photon gates

The multi-mode character of quantum fields imposes constraints on the implementation of high-fidelity quantum gates between individual photons. So far this has only been studied for the longitudinal degree of freedom. Here we show that effects due to the transverse degrees of freedom significantly affect quantum gate performance. We also discuss potential solutions, in particular separating the two photons in the transverse direction.Comment: 5 pages, 3 figures, published versio

2-(3-Cyano-4-{7-[1-(2-hy­droxy­eth­yl)-3,3-dimethyl­indolin-2-yl­idene]hepta-1,3,5-trien­yl}-5,5-dimethyl-2,5-dihydro­furan-2-yl­idene)malononitrile

The title compound, C29H28N4O2, excluding the hydroxyethyl and methyl groups, is slightly twisted from planarity so that the terminating indol-2-yl­idene and furan-2-yl­idene moiety planes subtend a dihedral angle of 6.27 (8)°. A small inwards fold in the polymethine atom chain is consistent with centrosymmetric dimer formation via O—H⋯N(cyano) hydrogen bonds. In the crystal, the mol­ecules pack in layers approximately parallel to the (10) plane via pairs of O—H⋯N and C—H⋯N(cyano) inter­actions

4-tert-Butyl-2-[2-(1,3,3-trimethyl­indolin-2-yl­idene)ethyl­idene]cyclo­hexa­none

The title mol­ecule, C23H31NO, has two alternative cyclo­hexa­none configurations at the 4-position in a ratio of 0.663 (3):0.337 (3). The plane of the five-membered planar ring in the indolin-2-yl­idene subtends an angle of 2.19 (7)° with its fused aromatic ring, an angle of 16.24 (8)° with the plane of the major cyclo­hexa­none configuration and an angle of 8.54 (15)° with the bridging planar ethyl­idene C atoms. These last atoms subtend an angle of 8.37 (16)° with the mean plane through the major cyclo­hexa­none configuration. The mol­ecules pack approximately parallel to the (01) plane via C—H⋯π and C—H⋯O inter­actions

Bis[4-(dimethyl­amino)phen­yl]diazene oxide

The asymmetric unit of the title compound, C16H20N4O, contains six independent approximately planar mol­ecules and is best described as a commensurate modulation of a P21/c parent. Two sets of disordered mol­ecules share almost the same locations (related by an in-plane translation), ensuring that the c-glide plane condition is not attained. C—H⋯O inter­actions provide structural cohesion. The site occupancy factors of the disordered molecules are ca 0.72/0.28 and 0.67/0.33

C—H⋯π packing inter­actions in 2-[5,5-bis­(4-benzyl­oxyphen­yl)-3-cyano-4-methyl-2,5-dihydro­furan-2-yl­idene]malononitrile

The title mol­ecule, C35H25N3O3, packs utilizing C—H⋯π attractive inter­actions causing the identical 4-benzyl­oxyphenyl groups to pack with different conformational angles. This difference is consistent with the variable inter­planar dihedral angles found in closely related structures

2-(4-{3-[1-(3-Bromo­prop­yl)-3,3-dimethyl-2,3-dihydro-1H-indol-2-yl­idene]prop-1-en­yl}-3-cyano-5,5-dimethyl-2,5-dihydro­furan-2-yl­idene)malononitrile

The backbone of the title mol­ecule, C26H25BrN4O, is approximately planar: the dihedral angle between the planes of the indoline ring system and the furan ring is 7.68 (14)°. In the crystal, layers lying parallel to (10) occur, with the mol­ecules inter­acting via weak C—H⋯N(cyano) and C—H⋯Br bonds and short N(cyano)⋯Br contacts [3.345 (4) Å]

O- vs. N-protonation of 1-dimethylaminonaphthalene-8-ketones: formation of a peri N–C bond or a hydrogen bond to the pi-electron density of a carbonyl group

X-ray crystallography and solid-state NMR measurements show that protonation of a series of 1-dimethylaminonaphthalene-8-ketones leads either to O protonation with formation of a long N–C bond (1.637–1.669 Å) between peri groups, or to N protonation and formation of a hydrogen bond to the π surface of the carbonyl group, the latter occurring for the larger ketone groups (C(O)R, R = t-butyl and phenyl). Solid state 15N MAS NMR studies clearly differentiate the two series, with the former yielding significantly more deshielded resonances. This is accurately corroborated by DFT calculation of the relevant chemical shift parameters. In the parent ketones X-ray crystallography shows that the nitrogen lone pair is directed towards the carbonyl group in all cases

(Dodecafluorosubphthalocyaninato)(4-methylphenolato)boron(III)

In the title compound, C31H7BF12N6O, mol­ecules are arranged into one-dimensional columns with an inter­molecular B⋯B distance of 5.3176 (8) Å. Bowl-shaped mol­ecules are arranged within the columns in a concave bowl-to-ligand arrangement separated by a ring centroid distance of 3.532 (2) Å between the benzene ring of the 4-methyl­phen­oxy ligand and one of the three five-membered rings of a symmetry-related mol­ecule

Seven 3-methylidene-1H-indol-2(3H)-ones related to the multiple-receptor tyrosine kinase inhibitor sunitinib

The solid-state structures of a series of seven substituted 3-methylidene-1H-indol-2(3H)-one derivatives have been determined by single-crystal X-ray diffraction and are compared in detail. Six of the structures {(3Z)-3-(1H-pyrrol-2- ylmethylidene)-1H-indol-2(3H)-one, C13H10N2O, (2a); (3Z)-3-( 2-thienylmethylidene)-1H-indol-2(3H)-one, C13H9NOS, (2b); (3E)-3-(2-furylmethylidene)-1H-indol-2(3H)-one monohydrate, C13H9NO2 center dot H2O, (3a); 3-(1-methylethylidene)-1H-indol- 2(3H)-one, C11H11NO, (4a); 3-cyclohexylidene-1H-indol- 2(3H)-one, C14H15NO, (4c); and spiro[1,3-dioxane-2,3'-indolin]- 2'-one, C11H11NO3, (5)} display, as expected, intermolecular hydrogen bonding (N-H center dot center dot center dot O=C) between the 1H-indol-2(3H)-one units. However, methyl 3-(1-methylethylidene)- 2-oxo-2,3-dihydro-1H-indole-1-carboxylate, C13H13NO3, (4b), a carbamate analogue of (4a) lacking an N-H bond, displays no intermolecular hydrogen bonding. The structure of (4a) contains three molecules in the asymmetric unit, while (4b) and (4c) both contain two independent molecules