Non-centrosymmetric Space Research Articles

Cd4InO(BO3)3: A New Nonlinear Optical Crystal Exhibiting Strong Second Harmonic Generation Effect and Moderate Birefringence

A new noncentrosymmetric cadmium indium borate, Cd4InO(BO3)3 (CIBO) has been successfully developed via a standard solid-state reaction. Its crystal structure was confirmed by the single crystal X-ray diffraction, which shows that CIBO belongs to the non-centrosymmetric and polar space group Cm. Its structure contains the distorted InO6 and CdOn (n = 6, 8) polyhedra, which link together by sharing an edge or corner to build a three dimensions framework with BO3 triangles accommodated in tunnels. Benefiting from the approximately parallel configuration of BO3 triangles, CIBO exhibited a strong second harmonic generation (SHG) effect (3 × KDP), and moderate birefringence of 0.077@1064 nm. Further optical and thermal characterizations suggest that CIBO possesses a wide transparent window and good thermal stability. Theoretical calculation reveals that the macroscopic SHG coefficients of CIBO results from the synergistic effect of the parallel arrangement of BO3 groups and d10 Cd2+ cation.

Structure and properties of two new heteroleptic bismuth(III) dithiocabamates of the general composition Bi(S2CNH2)2X (X = Cl, SCN)

Abstract The title compounds were prepared by precipitation from acidic solutions of the reactants in acetone/water. Bi(S2CNH2)2Cl (1) crystallizes in the non-centrosymmetric trigonal space group P32 with a = 8.6121(3) and c = 11.1554(4) Å, Z = 3; Bi(S2NH2)2SCN (2) in P21/c (monoclinic) with a = 5.5600(2), b = 14.3679(5), c = 12.8665(4) Å, and β = 90.37(3)°. In the crystal structure of 1 Bi3+ is in a sevenfold coordination of two bidentate and one monodentate S2CHNH2 − anions with an asymmetric coordination pattern of five Bi–S and two Bi–Cl− bonds. The linkage of these polyhedra via common Cl–S edges leads to a 1D polymeric structure with undulated chains propagating in the direction [001]. These chains are linked by strong and medium strong hydrogen bonds forming the 3D crystal structure. In the crystal structure of 2 the Bi3+ cation is in an eightfold coordination. The polyhedron can be described as a significantly distorted tetragonal anti-prism, capped by an additional S atom. Two of these prisms share a common quadrilateral face to form a “prism-double” (Bi2S10N2). These building units are linked by common edges, and the resulting 1D infinite angulated chains propagate along [100]. By contrast to organo-dithiocarbamate compounds, where C–H···X bridges are dominant, the interchain connections in the crystal structures of 1 and 2 are formed exclusively via N–H···S, N–H···Cl, and N–H···N interactions, generating the 3D networks. A significant eccentricity of the Bi3+ cation in the crystal structures of both complexes is observed. Both compounds emit light in the orange range of the electromagnetic spectrum.

Electron Diffraction Study of the Space Group Variation in the Al–Mn–Pt T-Phase

Binary high temperature “Al3Mn” (T-phase) and its extensions in ternary systems were the subjects of numerous crystallographic investigations. The results were ambiguous regarding the existence or lack of the center of symmetry: both Pna21 and Pnam space groups were reported. Our research on the Al–Mn–Pt T-phase allowed concluding that inside a continuous homogeneity region, the structure of the Al-rich T-phase (e.g., Al78Mn17.5Pt4.5) belongs to the non-centrosymmetric Pna21 space group, while the structure of the Al-poor T-phase (such as Al71.3Mn25.1Pt3.6) is centrosymmetric, i.e., Pnam. Following metallurgical and crystallographic considerations, the change in the symmetry was explained.

Synthesis and absolute structure of (R)-2-(benzyl-selan-yl)-1-phenyl-ethanaminium hydrogen sulfate monohydrate: crystal structure and Hirshfeld surface analyses.

A hydrogen sulfate salt, C15H18NSe+·HSO4 -·H2O or [BnSeCH2CH(Ph)NH3 +](HSO4 -), of a chiral selenated amine (R)-2-(benzyl-selan-yl)-1-phenyl-ethan-amine (BnSeCH2CH(Ph)NH2) has been synthesized and characterized by elemental analysis,1H and 13C{1H} NMR, FT-IR analysis, and single-crystal X-ray diffraction studies. The title salt crystallizes in the monohydrate form in the non-centrosymmetric monoclinic P21 space group. The cation is somewhat W shaped with the dihedral angle between the two aromatic rings being 60.9 (4)°. The carbon atom attached to the amine nitro-gen atom is chiral and in the R configuration, and, the -C-C- bond of the -CH2-CH- fragment has a staggered conformation. In the crystal structure, two HSO4 - anions and two water mol-ecules form an R 4 4(12) tetra-meric type of assembly comprised of alternating HSO4 - anions and water mol-ecules via discrete D(2) O-H⋯O hydrogen bonds. This tetra-meric assembly aggregates along the b-axis direction as an infinite one-dimensional tape. Adjacent tapes are inter-connected via discrete D(2) N-H⋯O hydrogen bonds between the three amino hydrogen atoms of the cation sandwiched between the two tapes and the three HSO4 - anions of the nearest asymmetric units, resulting in a complex two-dimensional sheet along the ab plane. The pendant arrangement of the cations is stabilized by C-H⋯π inter-actions between adjacent cations running as chains down the [010] axis. Secondary Se⋯O [3.1474 (4) Å] inter-actions are also observed in the crystal structure. A Hirshfeld surface analysis, including d norm, shape-index and fingerprint plots of the cation, anion and solvent mol-ecule, was carried out to confirm the presence of various inter-actions in the crystal structure.

Novel Ansa-Chain Conformation of a Semi-Synthetic Rifamycin Prepared Employing the Alder-Ene Reaction: Crystal Structure and Absolute Stereochemistry

Rifamycins are an extremely important class of antibacterial agents whose action results from the inhibition of DNA-dependent RNA synthesis. A special arrangement of unsubstituted hydroxy groups at C21 and C23, with oxygen atoms at C1 and C8 is essential for activity. Moreover, it is known that the antibacterial action of rifamycin is lost if either of the two former hydroxy groups undergo substitution and are no longer free to act in enzyme inhibition. In the present work, we describe the successful use of an Alder-Ene reaction between Rifamycin O, 1 and diethyl azodicarboxylate, yielding 2, which was a targeted introduction of a relatively bulky group close to C21 to protect its hydroxy group. Many related azo diesters were found to react analogously, giving one predominant product in each case. To determine unambiguously the stereochemistry of the Alder-Ene addition process, a crystalline zwitterionic derivative 3 of the diethyl azodicarboxylate adduct 2 was prepared by reductive amination at its spirocyclic centre C4. The adduct, as a mono chloroform solvate, crystallized in the non-centrosymmetric Sohnke orthorhombic space group, P212121. The unique conformation and absolute stereochemistry of 3 revealed through X-ray crystal structure analysis is described.

Interplay between Oxo and Fluoro in Vanadium Oxyfluorides for Centrosymmetric and Non-Centrosymmetric Structure Formation.

Herein, we report the syntheses of two lithium-vanadium oxide-fluoride compounds crystallized from the same reaction mixture through a time variation experiment. A low temperature hydrothermal route employing a viscous paste of V2O5, oxalic acid, LiF, and HF allowed the crystallization of one metastable phase initially, Li2VO0.55(H2O)0.45F5⋅2H2O (I), which on prolonged heating transforms to a chemically similar yet structurally different phase, Li3VOF5 (II). Compound I crystallizes in centrosymmetric space group, I2/a with a = 6.052(3), b = 7.928(4), c = 12.461(6) Å, and β = 103.99(2)°, while compound II crystallizes in a non-centrosymmetric (NCS) space group, Pna21 with a = 5.1173(2), b = 8.612(3), c = 9.346(3) Å. Synthesis of NCS crystals are highly sought after in solid-state chemistry for their second-harmonic-generation (SHG) response and compound II exhibits SHG activity albeit non-phase-matchable. In this article, we also describe their magnetic properties which helped in unambiguous assignment of mixed valency of V (+4/+5) for Li2VO0.55(H2O)0.45F5⋅2H2O (I) and +4 valency of V for Li3VOF5 (II).

Synthesis and Crystal Structures of Ethyl 2-(4-Methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate Dihydrate and Its Building Block 4-Fluoro-3-nitrobenzoic Acid

The title compound, ethyl 2-(4-methoxyphenyl)-1H-benzo[d]imidazole-5-carboxylate dihydrate (5), was synthesized and its crystal structure was studied by single-crystal X-ray diffraction technique. Compound 5 is crystallized in the centrosymmetric triclinic space group $$P\bar {1}$$ with Z = 4 and Z′ = 2, and unit-cell parameters of a = 8.9190 (3) A, b = 12.6888 (4) A, c = 14.7111 (5) A, α = 98.4855 (10)°, β = 101.6379 (9)°, γ = 95.4346 (10)° and V = 1599.43 (9) A3. Its starting material, 4-fluoro-3-nitrobenzoic acid (1), is crystallized in the non-centrosymmetric monoclinic space group P21 and Z = 4 with unit-cell parameters of a = 3.7170 (4) A, b = 12.6475 (13) A, c = 15.5237 (15) A, α = 90°, β = 91.9786 (16)°, γ = 90° and V = 729.35 (13) A3. It was noted that strong hydrogen bonds play important roles in the crystal packing of both compounds, especially in 5, in which the co-crystallized water molecules act as both strong hydrogen bond donor and strong hydrogen bond acceptor. Two molecule of compound 5 crystallized in a non symmetrical manner with four co-crystallized water molecules which play an important role in the crystal packing as strong hydrogen-bond donors.

Supramolecular self-assembly for designing non-centrosymmetric crystals based on Keggin polyoxometallates and crown ether

We report the synthesis of five novel crystals [(4-BrAni+)(DB[18]crown-6)]2[SMo12O402-]·2CH3CN (1), [(4-BrAni+)(B[18]crown-6)]2[SMo12O402-]·CH3CN (2), [(4-BrAni+)(B[18]crown-6)]3[PMo12O402-]·2CH3CN (3), [(3-AP+)3(B[18]crown-6)2][PMo12O403-] (4) and [NBu4+][(3-AP2+)(DB[30]crown-10)][PMo12O403-]·CH3CN (5) (4-BrAni+ = 4-bromoanilinium; B[18]crown-6 = benzo[18]-crown-6; DB[18]crown-6 = dibenzo[18]-crown-6; DB[30]crown-10 = dibenzo[30]-crown-10; 3-AP+ = 3-aminopyridinium; 3-AP2+ = 3-ammoniumpyridinium; NBu4+ = tetrabutylammonium). In order to construct non-centrosymmetric crystals, the five crystals were designed using a method to gradually introduce asymmetry into the building units. Crystal 1 was constructed with a symmetric supramolecular cation (SPC) [(4-BrAni+)(DB[18]crown-6)], resulting in a P21/n space group. The asymmetric SPC [(4-BrAni+)(B[18]crown-6)] was introduced into [SMo12O402-] to obtain crystal 2, which belongs to the symmetric P1[combining macron] space group. Introducing trivalent [PMo12O403-], [(4-BrAni+)(B[18]crown-6)] produced crystal 3 with a non-centrosymmetric Pc space group. The asymmetric sandwich SPC [(3-AP+)3(B[18]crown-6)2] was designed with multiple hydrogen bonding sites on the 3-AP+ cation, and crystal 4 was obtained with trivalent [PMo12O403-]. Crystal 4 has the properties of the chiral P1 space group. The distorted SPC (3-AP2+)(DB[30]crown-10) was constructed using flexible DB[30]crown-10, resulting in crystal 5 which matched the chiral P21 space group with trivalent [PMo12O403-]. This work focuses on strategies for the rational design of novel non-centrosymmetric crystals without a chiral synthon.

Experimental and Computational Studies of Bis(thiourea) Lead Chloride: Semi-organic Material for NLO Applications

Non liner optical single crystals of bis(thiourea) lead chloride (BTLC), belonging to the semi-organic material category, have been prepared by a slow solvent evaporation process. The single crystal X-ray diffraction analysis indicated the orthorhombic crystal structure and non-centrosymmetric Pna21 space group of the BTLC crystal. The crystalline nature of BTLC has been verified by means of the high resolution XRD (HRXRD) method. With the aid of elemental analysis, the purity and the stoichiometry of the crystal have been validated. Etching studies have been performed on BTLC using water etchant. The nature of electronic transitions, significant optical constant values and single oscillator parameters have been identified through ultra violet transmittance studies. The laser damage threshold (LDT) value of BTLC has been determined from LDT analysis. Theoretical calculations have been performed using the density functional theory (DFT) and the values of polarizability, hyperpolarizability and dipole moment of BTLC have been elucidated. Natural bond analysis (NBO) has also been done in order to gain knowledge on the nature of donor-acceptor interactions and charge distributions existing in the BTLC crystal. The frontier orbital HOMO-LUMO gap analysis assisted in arriving at the values of important global chemical molecular reactivity descriptors.

Crystal Structures of D-N-(2-Adamantyl)phenylglycinol and L-N-(2-Adamantyl)diphenylphenylalinol: Chiral Amino Alcohols Utilized as Ligands for Catalytic Asymmetric Hydroamination

ABSTRACTAmino alcohols are important ligands for the asymmetric catalytic hydroamination of aminoallenes to form chiral pyrrolidines. Herein, we report the crystal structures of two chiral amino alcohols, D-N-(2-Adamantyl)phenylglycinol and L-N-(2-Adamantyl)diphenylphenylalinol, that function as ligands within transition metal complexes that catalyze the hydroamination of aminoallenes. Both molecules crystallize in the noncentrosymmetric orthorhombic space group P212121. Inter- and intramolecular hydrogen bonding plays an important role in stabilizing each alcohol in the solid state in the absence of a transition metal. The presence of these hydrogen bonds has been verified by single crystal X-ray diffraction and their overall strength determined by computational methods.

Dinitroxide biradical crystals with polar order

A dinitroxide biradical (dCdO) has the peculiar tendency to crystallize in non-centrosymmetric polar space groups either as a stable dichloromethane solvate or as a pure phase. The molecules arrange with no compensation of their dipolar moment resulting in net macroscopic polar order.

Interconnection of [V15As6O42(H2O)]6- Clusters by Cu2+-centered Complexes: Synthesis, Crystal Structure and Selected Properties

Abstract The compound {[Cu(C5H14N2)2]3[V15As6O42(H2O)]} was synthesized under solvothermal conditions. During the reaction the VV species of NH4VO3 are reduced to VIV providing the 15 reduced VIV centers in the anionic cluster. The compound crystallizes in the non-centrosymmetric orthorhombic space group P212121 with four formula units in the cell, V =9464:8(4) Å3. The structure features [V15As6O42(H2O)]6- anions which are joinded by Cu2+-centered complexes to form linear chains. If a long Cu-O bond is considered as weak intermolecular interaction a three-dimensional network is generated. The compound is partially soluble in water as evidenced by UV/Vis spectroscopy and mass spectra. The magnetic susceptibility of the compound is dominated by strong intra-cluster antiferromagnetic exchange interactions.

Synthesis, Crystal Structure, Thermal and Dielectric Properties of a New Semi-organic Crystal: 2[N(2-Aminoethyl)-1,3-propanediaminium] octachlorodimercurate, tetrachloromercurate

A novel semi-organic hybrid material, (C5H18N3)2Hg2Cl8⋅HgCl4, was synthesized, and its structure was determined at room temperature in the non-centrosymmetric monoclinic space group P212121 with the following parameters: a = 21.0921(7), b = 11.7288(4), c = 12.6801(5) A, Z = 4. Its crystal structure was determined and refined down to R = 0.0549 and Rw = 0.1303. The examination of the structure shows a layer arrangement parallel to the b axis: the anionic layer may be considered as a succession of layers built up distorted triangular bipyramid [HgCl3]−. The crystal packing is governed by means of the ionic N–H…Cl hydrogen bonds, forming a three dimensional network. DSC measurement reveals a transition at T = 418 K and dielectric measurements were performed to discuss the mechanism of the phase transition. The evolution of dielectric constant as a function of temperature of single crystal has been investigated in order to determine some related parameters.

Crystal structure, thermal behavior and spectroscopic studies of a new organic hydrogen arsenate

The present paper undertakes the study of a title organic-inorganic hybrid material 2-amino-3-benzyloxy pyridinium dihydrogenmonoarsenate, [C12H13N2O]H2AsO4, which has been synthesized by slow evaporation at room temperature using 2-amino-3-benzyloxypyridine as the structure-directing agent. The structure was determined by single-crystal X-ray diffraction at 296 K. This compound is crystallized in the noncentrosymmetric orthorhombic space group P212121 with the lattice parameters a = 4.89 (7), b = 10.41 (1), c = 26.79 (3) Å, V = 1364.3 (3) Å3, and Z = 4. The crystal structure has been determined and refined to R1 = 0.0363 and wR2 = 0.1246 using 5438 independent reflections. The atomic arrangement can be described by infinite anionic chains running parallel to the [100] direction. The organic entities are located between these chains. H-bonds connecting the different species play an important role in the one-dimensional network cohesion. This compound is also characterized by solid-state 13C MAS NMR, IR, Raman spectroscopy and TG-ATD thermal analysis. Moreover, protonic conduction of this compound determined by impedance has been studied in the temperature range 299 - 403 K.

Synthesis and characterization of calcium(II) coordination polymers based on phenylacetic acid

The syntheses, crystal structures, and thermal properties of the coordination polymers [Ca(H2O)2(L1)2] · H2O (1) (L1 = 4-methoxyphenylacetate) and [Ca(H2O)2(L2)2] · 2H2O (2) (L2 = 2-chlorophenylacetate) are described. 1 and 2 can be dehydrated to the anhydrous [Ca(L1)2] (1a) or [Ca(L2)2] (2a), respectively. Compounds 1 and 2 crystallize in the non-centrosymmetric monoclinic space group P21 and the structures consist of a central Ca(II), two terminal waters, and two crystallographically unique L1 (or L2) anions, one of which functions as a chelating bidentate ligand. The second independent L1 (or L2) is tetradentate, coordinated in a μ3-bridging mode leading to the formation of a 1-D coordination polymer. In the infinite chain extending along the b-axis, each Ca(II) is eight-coordinate and bonded to two terminal waters and six oxygens from four different L1 or L2 ligands.

Molecular Structure of Methyl 1-Isopropenyl- 5a,5b,8,8,11a-Pentamethyl-9-OXO-10-[(E)-1-Phenylmethylidene] Perhydrocyclopent [a]Chrysene-3a-Carboxylate

The molecular structure of methyl 1-isopropenyl-5a,5b,8,8,11a-pentamethyl-9-oxo-10-[(E)-1phenylmethylidene]perhydrocyclopent[a]chrysene-3a-carboxylate II is determined. Compound II C38H52O3 crystallizes in the non-centrosymmetric P21 space group with the cell parameters: a= 11.4450(8) A, b = 11.1995(8) A, c = 12.5179(9) A, β = 93.984(2)°.

Basic Co-rich decagonal Al-Co-Ni: Average structure

The two-layer average structure of the high-temperature phase basic Co-rich decagonal ${\text{Al}}_{72.5}{\text{Co}}_{18.5}{\text{Ni}}_{9}$ was determined based on single-crystal x-ray diffraction data. The five-dimensional (5D) structure model was refined in the noncentrosymmetric 5D space group $P\overline{10}m2$ (112 parameters, $wR=0.123$ and $R=0.156$ for 957 reflections). The close relationship of the model structure with that of W-Al-Co-Ni, a $⟨3/2,2/1⟩$ approximant, is shown.

The role of functional nitro and cyano groups in the self‐assembly of 1,3‐dithiole‐2‐thione–halogen adducts

AbstractThe synthesis of five new dihalogen/interhalogen charge transfer adducts featuring cyano and nitro functionalized 1,3‐dithiole‐2‐thiones have been prepared and characterized by x‐ray crystallography. The structures feature a complex series of intermolecular close contacts between heteroatoms, as well as hydrogen bonding, to give highly ordered, polymeric assemblies. The adduct 4.IBr crystallizes in a noncentrosymmetric chiral space group and features a stack of molecules assembled through hydrogen bonds. The functional groups of all adducts participate in networks of close contacts, but do not affect the coordination environment of the dihalogen/interhalogen species. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:176–184, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20327

Synthesis and Crystal Structure of Novel Planar Chiral Diferrocenylimine-Diols X-Ray Crystal Structure of [(η5-C5H5) Fe{ (η5-C5H3) CPh2OHCH (CH3) N=CHC6H4CH=NCH (CH3) CPh2OH (η5-C5H3) }Fe (η5-C5H5)

Four novel planar chiral diferrocenylimine-diols 6 (6a, 6b, 6c, 6d) have been designed and prepared, and the structure of 6a determined by X-ray crystallography. Compound 6a [(η5-C5H5) Fe{ (η5-C5H3) CPh2OHCH (CH3) N=CHC6H4CH=NCH (CH3) CPh2OH (η5-C5H3) }Fe (η5-C5H5)] is enantiomerically pure and crystallises in the noncentrosymmetric P212121 space group, exhibiting a “∩” shape, phenyl ring as a bridge linking two ferrocenes on both sides via C=N, and the pair of ferrocenyl groups adopting the E-configuration.

Large second-order optical nonlinearities of s-triazine derivatives: View from micro molecules to macro crystals

Three s-triazine derivatives have been synthesized and their structures been determined. These are Compound I: 2,4-dimethyl-6-(p-N,N-dimethylaminostyryl)-s-triazine (abbreviated to NMe-1), Compound II: 2,4-dimethyl-6-(p-N,N-diethylaminostyryl)-s-triazine (to NEt-1), and Compound III: 2-methyl-4,6-bis(p-N,N-dimethylaminostyryl)-s-triazine (NMe-2). NMe-1 and NEt-1 molecules belong to the D-π -A type with a one-dimensional charge-transfer character. NMe-1 crystallizes to centrosymmetric \(P\bar 1\) space group, while NEt-1 to non-centrosymmetric polar Cc space group with all of the molecular charge-transfer axes taking the same orientation. Under the irradiation of 1064 nm fundamental laser, NEt-1 powder crystals radiate a 2-order harmonic light with an intensity 46.8 times that of urea. The ∧ A typed NMe-2 molecule, which has a two-dimensional charge-transfer character, crystallizes to polar P21 space group. Its powder crystals exhibit a 2-order harmonic intensity 46.2 times that of urea. The quantum chemical calculations and tensor analyses have been carried out to reveal the dependence of the macro 2-order nonlinear optical (NLO) efficiency on the micro 2-order NLO coefficients (β) and on the crystalline packing styles.