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Single crystals of the trihydrated praseodymium cyclotriphosphate PrP3O9·3H2O were grown for the first time, using a classical method of aqueous chemistry and characterized by single crystal X-ray diffraction. PrP3O9·3H2O is isostructural with LnP3O9·3H2O (Ln = La, Ce and Nd). It crystallizes in the hexagonal system with space group P6¯(C3h1), with lattice parameters: a = 6.7677(4) A, b = 6.7677(4) A, c = 6.0501(4) A, V = 239.98(3) A3, Z = 1 and Dx = 2.988 g cm−3. The crystal structure is resolved for the first time, with final R(F2) = 0.0175 and Rw(F2) = 0.0417 for 396 independent reflections (F02≥2σ(F02)). The P3O93− cyclic anions have a plane configuration with C3h symmetry. The nearest neighbours of the rare earth ion are six oxygen atoms belonging to the P3O93− anions. Pr3+ ions occupy sites with C3h symmetry. The energies of the crystal vibrational modes are obtained from infrared (IR) and Raman spectra. Optical absorption measurements and emission spectra under selective excitation in the Pr3+ (4f2) 3PJ (J = 0, 1, 2) levels, at room and liquid-helium temperatures, are reported. The observed fluorescence originates mainly from 3P0 with a decay time on the order of 10 ns, regardless of temperature.

The reaction of a racemic mixture of (2R,2'S)- and (2S,2'R)-N-(p-tolylsulfonyl)-2-pyrrolidinyl-2-propanol, prepared from (S)-proline, with 2,3,4-tri-O-acetyl-alpha-L-fucopyranosyl trichloroacetimidate led to both diastereoisomers of the title compound after O-deacetylation.

[reaction: see text] Ugi reaction between an (S)-alpha-amino acid, an aromatic aldehyde, and an isonitrile proceeds best under catalysis by TiCl(4) in MeOH. The sense of diastereoinduction is (S,S).

The reaction between yttrium chips or Y5O(OPri)13 and 2-isopropoxyethanol afforded the title compound. It has been characterized in the solid state by X-ray diffraction and in solution by 1H and 89Y NMR spectroscopy.

Reaction of pseudo‐glucal 1 with Grignard reagents derived from 1‐bromo‐4‐(trimethylsilyloxy)benzene, 1‐bromo‐4‐methoxybenzene, 1‐bromo‐4‐methoxymethoxybenzene, 1‐bromo‐4‐dimethylaminobenzene, in the presence of a catalytic amount of NiCl2(dppe), gives the corresponding unsaturated β‐C‐aryl glycosides 2. Desilylation and hydrogenation of 2 leads to β‐C‐aryl glycosides 4, which can be used as chiral precursor compounds in the synthesis of chiral liquid crystals. Combination of 4 with arylaldehydes leads to compounds 5–7, whereas reaction with p‐alkoxysubstituted phenylboronic acids gives the trioxaboradecalins 8–11. The mesogenic properties of these compounds are strongly influenced by the nature of the substituent on the phenyl ring in the molecule. †This paper is dedicated to Professor Gerard Descotes on the occasion of his 70th birthday.

Single crystals of praseodymium polyphosphate Pr(PO{sub 3}){sub 3} were grown for the first time using a flux method and characterized by single-crystal X-ray diffraction. Pr(PO{sub 3}){sub 3} is isostructural with Nd(PO{sub 3}){sub 3} and La(PO{sub 3}){sub 3}. It crystallizes in the orthorhombic system with space group C222{sub 1} (D{sub 2}{sup 5}), with lattice parameters: a=11.234(1) A, b=8.5289(8) A, c=7.3199(8) A. The crystal structure was resolved with final R(F{sup 2})=0.0359 and R{sub w}(F{sup 2})=0.0924 for 402 independent reflections (F{sub 0}{sup 2}{>=}2{sigma}(F{sub 0}{sup 2})). In the Pr(PO{sub 3}){sub 3} structure, oxygen atoms form a PO{sub 4} tetrahedron around each P atom and a PrO{sub 8} polyhedron around each Pr atom. The PO{sub 4} tetrahedra share corners to produce helical chains and the PrO{sub 8} polyhedra share edges to form zigzag chains. The shortest Pr-Pr distance is 4.253 A. The energies of the vibrational modes of the crystal are obtained from the infrared and Raman spectra. Measurements of emission spectra under pulsed laser excitation in the Pr{sup 3+} (4f{sup 2}) {sup 3}P{sub J} (J=0, 1, 2) levels and decay times of the observed emissions are reported both at room and liquid-helium temperatures. X-ray excitation leads to intense ultraviolet 4f{sup 1}5d{sup 1}{yields}4f{sup 2} bandmore » emissions in the 200-300 nm spectral range with decay times in the order of 6 ns both at room and low temperatures.« less

The resolution of racemic bromofluoroacetic acid (BrFHCCO 2 H) 1 was effected by crystallisation of its diastereoisomeric α-methylbenzylamine salts. The crystal structure of the p salt (+)- 3a {(+)-BrFHCCO 2 H·( R )-(+)-α-methylbenzylamine} was solved by X-ray crystallography and the ( S )-(+)/( R )-(−) absolute configuration was established for 1 . Diastereoisomeric esters 5a and 5b , obtained by addition of bromofluoroacetic acid to enantiomerically pure epoxychroman 4 , were used to determine the enantiomeric excess of 1 by 19 F NMR. Moreover, the diastereoisomerically pure ester 5a , resulting from addition of enantiomerically pure (+)- 1 to 4 , gave single crystals and its X-ray crystal structure corroborated the ( S )-(+)/( R )-(−) absolute configuration of 1 .

The reaction of the tri-(benzaldehyde)-substituted cyclotriveratrylene 6 with phosphotrihydrazide under high dilution conditions gives rise to the novel thiophosphorylated hemicryptophane 1. 1 is representative of a new family of molecular receptors providing a molecular cavity available for neutral and charged guests. In the crystal, compound 1 encapsulates one toluene molecule. Un he′micryptophane thiophosphoryle′: structure du complexe d'inclusion avec le toluene. La re′action du cyclotrive′ratrylene 6, trisubstitue′ par des groupements benzalde′hyde, avec le phosphotrihydrazide dans des conditions de haute dilution, conduit au nouveau he′micryptophane 1. 1 repre′sente une nouvelle famille de re′cepteurs mole′culaires contenant une cavite′ pouvant pie′ger des substrats neutres ou charge′s. Dans le cristal, le compose′ 1 encapsule une mole′cule de toluene.

International audience; We describe the synthesis and quadratic hyperpolarizability properties of [n]-polyenovanillins, a new family of push−pull polyenes deriving from vanillin, thiovanillin, and isothiovanillin. Twenty-five [n]-polyenovanillins of structure 3,4-(RO;R‘S)C6H4(CHCH)nCHO [with n = 1−6 and R, R‘ = Me or n-Bu] were synthesized by using a Wittig−Horner polyvinylogation methodology, and the structure of one of these was established by single-crystal X-ray crystallography. The UV−vis absorption and fluorescence spectra of these polyenovanillins were recorded and interpreted in light of CNDO/S calculations that allowed the identification of the different transitions. EFISH measurements provided up to 350 × 10-30 esu (for 14, n = 6) with an exponential increase of the quadratic hyperpolarizability with the conjugation length. These data were satisfactorily interpreted by means of a CNDO/S/NLO method which provided information as to the relative orientation of the dipole moment μ and βvec, the vector part of the hyperpolarizability tensor. In the sulfur-substituted series, there is a significant divergence between the orientation of μ and βvec, which in turn leads to an underestimation of β in the EFISH method. The calculation also revealed that when the length of the polyenic chain increases, the charge transfer from the donor toward the acceptor actually tends to concentrate on the polyenic chain rather than on the aldehyde group.

The hetero-armed p(tert-butyl)calix[4]arene 1 was synthesized by a stepwise procedure. This ligand presented a very strong complexing behavior towards Cu1, giving the chiral complex 2 and parent species when reacted with CuII salts. High-resolution NMR techniques were employed for the characterization of 2, demonstrating notably exchange processes between its two enantiomeric forms. The racemic nature of 2 was confirmed by X-ray crystal-structure analysis.

p-cumylcalix[8]arene crystallizes with 5 DMSO molecules in the tetragonalspace group P4. The parameters have values: a = b = 17.443(3), c = 9.829(2) A. Refinement based on 2454 observed reflections led to afinal R value of 0.073. Four dimethylsulfoxide molecules are connected by hydrogenbonds to the calixarene. The macrocycle shows an alternate conformation around the 4 axis. In the network, another DMSO in disordered manner is a foundbetween the calixarenes.

The crystal structure of p-cumylcalix[6]arene·2.5 dimethylformamide has revealed that the compound exists in the double partial cone conformation. The DMF molecules are bound to the calixarene via hydrogen bonds. The compound crystallizes in the triclinic space group P1 with a = 17.328(3), b = 17.981(3), c = 17.040(3) A, α = 116.56(2), β = 112.42(1), γ = 76.18(2)°, and Dc = 1.165 g cm−3 for Z = 2. Refinement based on 9418 observed reflections led to a final R value of 0.08.

The title compound (C7N2H10, HC1, 1/2H2O) crystallizes in the space groupC2/c with cell parameters:a=11.651(9),b=16.309(1),c=9.167(1)A,β=94.95(3)°,Z=8, withd=1.287 g cm−3. One of the chlorine atoms lies on a twofold axis, the second and the oxygen atom of the water molecule have disordered positions. Intermolecular interactions through hydrogen bonds are established between nitrogen atoms of the pyrazole ring and chlorine atoms or the water molecule. In this way, chains of ‘molecules’ are built; these chains, through van der Waals interactions, form layers which are stacked in the a direction. The1H,13C, and15N NMR (this last using the double labelled compound) have been recorded in solution and the13C NMR spectrum also in the solid state (CP/MAS technique). The NMR parameters (δ andJ's) thus obtained are discussed using the molecular structure.

Hydroquinone forms a 1 : 1 : 6 complex with 18-crown-6 and water. Crystals of this complex are monoclinic, space groupP21/a witha = 14.289(1),b = 7.972(1),c = 11.596(1) A, β = 97.72(1)°,Z = 2,D c = 1.22 g cm−3. The hydroquinone and crown ether molecules lie on centres of symmetry with the crown in theD3d conformation. The water molecules act as a bridge between hydroquinone and the crown ether. The structure consists of molecules linked by a 3-dimensional network of hydrogen bonds: the hydroquinone and two water molecules lie roughly in the (001) plane; the crown ether and four water molecules form bipyramidal structures which are stacked in layers alternating with the previous planes.

Benzimidazole-4,7-diones 3a and 3b were synthesized and submitted to hetero Diels–Alder reactions with azadienes 4 and 5 to afford imidazo[4,5-g]quinoline-4,9-diones 6–9. The structure of the latter was assigned by X-ray diffraction, 1H NMR NOE DIFF experiments or by a molecular dynamics study. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Information about the orientation and dynamics of a chloroform molecule encaged in cryptophane-A and cryptophane-E is obtained by means of Raman microspectrometry. The microscopy technique allows us to study the two observed crystalline structures of the CDCl 3 -cryptophane-A complexes separately. The spectra, recorded under different polarization conditions, are compared with those of CHCl 3 -D 3 0 -cryptophane-A and analyzed in light of the crystalline structures determined by X-ray diffraction. The spectral analysis is improved by ab initio calculations performed for the isolated guest and host molecules. The orientation of the encaged chloroform with the C-H bond pointing toward the center of the cyclotriveratrylene structures is confirmed. The vCD (or vCH) stretching wavenumber of chloroform is red shifted upon complexation as compared to the wavenumber of the gaseous isolated state. This red shift, larger for the CDCl 3 -cryptophane-E complex than for the CDCl 3 -cryptophane-A complex, is the signature of stronger binding host-guest interactions with cryptophane-E. In addition, the analysis of the band shape of the vCD stretching vibration of chloroform suggests different rotational dynamics for the guest molecule encaged in cryptophane-A or in cryptophane-E. This work illustrates the capability of the Raman microspectrometry technique to investigate molecular recognition phenomena in solids.

The title compound, dicarbonyl-1kappa(2)C-di-mu-chloro-1:2kappa(4)Cl-[cis,cis-2(eta(4))-1,5-cyclooctadiene]dirhodium(I), [Rh(2)Cl(2)(C(8)H(12))(CO)(2)], consists of a dichloro-bridged dimer of rhodium, with a non-bonded Rh.Rh distance of 3.284 (2) A. One Rh atom is coordinated to two carbonyl ligands, while the other Rh atom is coordinated to the cyclooctadiene moiety.

In the complex between p-cumyl­calix­[4]­arene and para-xyl­ene [systematic name: 4-(2-phenyl­iso­propyl)­calix­[4]­arene–1,4-di­methyl­benzene (1/1)], C64H64O4·C8H10, the macrocycle has a cone conformation, which is stabilized by intramolecular hydrogen bonds. The guest para-xyl­ene mol­ecule is situated inside the cavity, giving an endo-calix complex. The host and guest molecules both have twofold rotation symmetry.

Calixarenes are cyclic phenolic oligomers mixing complexation abilities for neutral or ionic guests and a good functionalization flexibility with a high thermal stability. Since the pionnering work of Gutsche [1], they became a promising chemical platform for the building of a new and large family of synthetic receptors [2].

The internal angles in the benzene ring and the external C-C-O angles have been determined by the MNDO method for phenol, the three cresols and 4-nitrophenol. Despite the fact they are supposed to be related to the isolated molecules, the results are in very good agreement with crystal structure determinations.

Two important precursors of phenolic resins manufactured from phenol are studied. Crystal structures and 13C NMR spectra in solid state are determined for these pure compounds. The thermal polycondensation of one precursor is monitored by 13C NMR.

Twelve substances derived from phenol or 4-alkylphenol, six of which are precursors of phenolic resins, have been prepared by condensation of the phenol with paraformaldehyde or by further reaction of one of these with the starting phenol. Two cyclic oligomers belonging to the class of calixarenes or cyclophanes have been isolated and characterized. Single crystals of some precursors have been obtained and their crystalline structures have been determined. The thermal decomposition of precursors of phenolic resins have been investigated. Their solid state behaviour and their relative reactivities in acidic and basic conditions have been evaluated. The obtained substances can be considered as important intermediates. They are both sufficiently stable and highly reactive.

It is shown that the charge transfer is negligible in the ground state for organic charge transfer complexes between phenols and quinones. Our objective Is to determine the origin of the stability of the complexes. The geometric, electronic and energetic properties of these complexes were examined by three techniques, crystal structure determination by X-ray diffraction, spectrum and charge transfer calculation by quantum chemical methods, and lattice energy computation.

Experimentally we show that convex and concave decreases oforganic single crystals lead to the same modifications when the decreases are obtained either by a chemical or a physical way. The chemical decrease is obtained either by the action of gaseous chlorine on the phenol single crystal without any solvent or catalyst or by the action of isobutylene on single crystals doped with sulphuric acid. In convex decrease the crystal becomes round shaped while if the decrease is made in a cavity drilled in the solid, crystallographic faces appear.

During the past fifteen years there has been a number of detailed studies devoted to the chemistry of organic molecular solids and made by a number of groups involving chemists and crystallographers. These workers were interested in the reactions of the organic solids subjected either to a physical agent like light or heat or to a chemical one which can be a solid, a liquid or a gas.1

The hydrogenation of organic solid substances like phenols and phenoxides under mild conditions has been studied. It is shown that those reactions take place in the solid state. Because of the lack of fluid phase the classical catalysis processes cannot explain the high conversion ratios obtained; the spillover effect and the existence of mobile hydrogenating species are discussed.

Differentes substances organiques solides, en poudre ou sous forme de monocristaux, sont mises en reaction avec le chlore gazeux dans le but de conna[icaron]tre les produits obtenus lorsque ces substances sont traitees soit pures soit en association avec une autre substance. Les trois systems binaires suivants ont ete etudies: le compose defini dichloro-3,5 phenol-dimethyl-2,6 phenol, la solution solide continue isopropyl-4 phenol-methyl-3 isopropyl-4 phenol et le complexe de transfert de charge α-naphto-methyl-2 naphtoquinone-1,4. Il appara[icaron]t que les interactions moleculaires entre les composes de ces trois systemes ne modifient pratiquement pas les resultats obtenus avec les composes purs. Le facteur important est l'accessibilite aux centres reactifs.

The internal angles in the benzene ring and the external C-C-O angles have been determined by the MNDO method for phenol, the three cresols and 4-nitrophenol. Despite the fact they are supposed to be related to the isolated molecules, the results are in very good agreement with crystal structure determinations.

Transparent single crystals of different phenols are grown from the melt or from saturated solution in various solvents. Crystal structure determination are studied by X-Ray or neutron diffraction methods. Among them several are used to measure physical properties. For this paper we choose non linear optical properties. Measurements first made on powder to know the importance of the phenomena have to be repeated on single crystals in several directions to know coefficients of the NLO tensor. At present time data are known for 3-methyl-4-isopropylphenol (tetragonal - space group P41). These negative uniaxial crystals are found to have NLO coefficients (d333, d331) = (1.1, 1.4) x 10-9 esu respectively. On the other hand, data show that nx at 0.53 μ is almost equal to nz at 1.06 μ (Δn = 0.0023). This fact means that the coherence length for the second harmonic generation at 1.06 μ is very large. If in fact the two indices were identically equal, we would have a very useful crystal as a device for doubling the readily available 1.06 μ source up to 0.53 μ, particularly since there are only few crystals known which have this quality. Same measurements have to be made on an isomorphous compound, 4-isopropylphenol. The two compounds syncrystallizes to give solid solution ; so it will be interesting to grow, if possible, single crystals of intermediate composition and made NLO measurements on them.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

During the last twenty years there has been a number of detailed studies devoted to the chemistry of organic molecular solids and made by a number of groups involving chemists and crystallographers.

Polar reactivity differences have been found on the two faces of a slice cut along a polar axis in a 3-methyl 4-isopropyl phenol crystal. A case of absolute asymetric synthesis is noted during the chlorination of the same compound.