Relationship between the structure and luminescent properties for two crystal modifications of N-butyl-2-cyano-3-[4-(dimethylamino)phenyl]-2-propenamide

Two crystal modifications (1o and 1y) of N-butyl-2-cyano-3-[4-(dimethylamino)phenyl]-2-propenamide, which differ in the color of crystals and the color of luminescence, have been studied by X-ray diffraction and spectral-luminescence methods. The corresponding bond lengths and bond angles in the molecules of two crystal modifications are virtually identical. In both crystal structures, there are two systems of weak intermolecular interactions: π-stacking interactions and -CN…H-N hydrogen bonds involving nitrile and NH groups. In the crystal structures, two hydrogen bonds connect pairs of molecules into centrosymmetric dimers. The N…H distances are 2.21 and 2.41 Å in 1o and 1y, respectively. The interplanar distances in the π-stacked systems of 1o and 1y are 3.33 and 3.41 Å, respectively. Both types of weak interactions are stronger in 1o than in 1y, which accounts for a larger shift of absorption and luminescence bands for the former compound.     

Synthesis and structure of two crystalline modifications of Bis(1,10-Phenanthroline)trinitratoeuropium(III) Eu(NO3)3(Phen)2

Two crystalline modifications (I and II) of the phenanthroline complex of europium nitrate with the same chemical composition, Eu(NO₃)₃(Phen)₂, are synthesized under different conditions by varying the solvents, temperatures, and crystallization rates. The crystal structures of these modifications are determined using X-ray diffraction. Crystalline modifications I and II differ in the unit cell parameters and the positions of the complexes in the unit cell. The geometric characteristics of the complexes in the structures of compounds I and II differ insignificantly. Crystals of compound I belong to the isostructural family Ln(NO₃)₃(Phen)₂ (Ln = La-Lu). Crystals of compound II (new phase) are studied for the first time. Crystals of I and II are monoclinic, space group C2/c, and Z = 4. The unit cell parameters are as follows: a = 11.1555(10) Å, b = 17.9698(10) Å, c = 13.0569(10) Å, β = 100.507(10)°, and V = 2572.1(3) ų for modification I and a = 9.5153(10) Å, b = 15.4546(10) Å, c = 17.1763(10) Å, β = 93.451(10)°, and V = 2521.3(3) ų for modification II. The difference between the molecular complexes in the structures of compounds I and II is revealed by the superposition method. Complexes II are arranged along the C ₂ axis and are statistically disordered with respect to this axis.     

Molecular and crystal structures of 4-acylphenyl 4′-alkyloxybenzoates

The crystal structures of four liquid-crystal (LC) compounds belonging to 4-acylphenyl 4′-alkyloxybenzoates with the general formula C _n H_{2n + 1}-C(O)-C₆H₄-O-C(O)-C₆H₄-O-C _m H_{2m + 1} numbered as 1/6, 1/7,2/7, and 3/7 (the numbers in the code indicate the ratios of the numbers of alkyl-chain units, n/m) are determined. Compounds 1/6 and 1/7 form smectic and nematic phases, but they are monotropic mesogens, whereas compounds 2/7 and 3/7 form only an enantiotropic smectic phase. Compound 3/7 crystallizes in two crystal modifications—triclinic with Z′ = 2 (3/7 _tr ) and monoclinic with Z′ = 4 (sp. gr. P2, 3/7 _mon ). All crystals consist of alternating aromatic and aliphatic regions and are characterized by the presence of weak directional interactions, such as C-H...O hydrogen bonds and π-stacking interactions. This provides the necessary conditions for the formation of a mesophase, and the existence of two types of structure-forming units is in line with the formation of a smectic phase. An explanation is proposed for the monotropic properties of 1/6 and 1/7.     

Synthesis and the crystal and molecular structure of two modifications of bis(1,10-phenanthroline)trinitratoerbium(III) Er(NO3)3(Phen)2

Two crystalline modifications (I and II) of the phenanthroline complex of erbium nitrate with the same chemical composition, Er(NO₃)₃(Phen)₂, are synthesized by a procedure similar to that used for preparing the phenanthroline complexes of europium nitrate. The crystal structures of these modifications are determined using X-ray diffraction. Crystals of compound I belong to the isostructural family Ln(NO₃)₃(Phen)₂ (Ln = La-Lu). Crystals of compound II are isostructural to those of modification II (new phase) of the Eu(NO₃)₃(Phen)₂ compound. Crystals of I and II are monoclinic, space group C2/c, and Z = 4. The unit cell parameters are as follows: a = 11.126 Å, b = 17.815 Å, c = 12.976 Å, β = 100.45°, and V = 2529 ų for modification I and a = 9.459 Å, b = 15.463 Å, c = 17.076 Å, β = 93.52°, and V = 2493 ų for modification II. The molecular complexes in the structures of compounds I and II are nearly identical. The mean lengths of the Er-N and Er-O bonds are equal to 2.500 and 2.466 Å in compound I and 2.508 and 2.457 Å in compound II, respectively. The difference between the structures of compounds I and II is associated with the difference between intermolecular interactions in the unit cell.     

Alkylation of a bioinspired high spin Ni(II)N3S2 complex with bifunctional reagents

Crystal structures of two S-alkylated complexes generated from the reaction of iodoacetamide and iodoethanol with an air and moisture sensitive high spin Ni(II) pentacoordinate triaminodithiolate complex, 1 are determined by X-ray structure analysis. Crystals of complex 2, [NiC₁₆H₃₁N₅O₂S₂]I₂, are triclinic, sp. gr. $P\bar 1$ , Z = 2. Crystals of complex 3, [NiC₁₆H₂₈N₃O₂S₂]I₂, are monoclinic, sp. gr. P2₁/c, Z = 4. Structures of complexes 2 and 3 are very similar: one of the S-acetamide (2) or S-ethanol (3) groups coordinates to the Ni center through the oxygen atom forming N₃S₂O hexacoordination; the other group remains unbound to the Ni and left dangling. Crystal packing shows that complexes 2 and 3 interact with the iodide counterions, and that only complex 2 interact with neighboring molecules; some of these close intermolecular contacts include H-bonding interactions.     

Crystal structure and vibrational spectra of two cadmium halide complexes with 1,2-Bis[2-(Diphenylphosphinylmethyl)phenoxy]ethane (L 1) and 1,3-bis[2-diphenylphosphinylmethyl)phenoxy]propane (L), CdBr2 ⋅ L 1 and CdI2 ⋅ L

Two cadmium halide complexes with 1,2-bis[2-(diphenylphosphinylmethyl)phenoxy]ethane (L ¹) and 1,3-bis[2-(diphenylphosphinylmethyl)phenoxy]propane (L), namely, CdBr₂ ? L ¹ (I) and CdI₂ ? L(II), have been synthesized. An analysis of their vibrational spectra is carried out. The structures of I and II are determined by X-ray diffraction. Crystals I are monoclinic, a = 31.562(6) Å, b = 13.548(3) Å, c = 18.733(4) Å, β = 91.28(3)°, space group C2/c, Z = 8, and R = 0.051 for 3776 reflections. Crystals II are triclinic, a = 11.803(2) Å, b = 12.554(3) Å, c = 14.686(3) Å, α = 90.30(3)°, β = 90.29(3)°, γ = 106.08(3)°, space group $P\bar 1$ , Z = 2, and R = 0.043 for 4916 reflections. Compounds I and II exhibit a polymeric chain structure. The potentially tetradentate ligands L ¹ and L are coordinated to the metal atoms only through two phosphoryl oxygen atoms and fulfill the bidentate bridging function. The environment of the Cd atom is completed to the tetrahedral coordination by two Br atoms in complex I and two I atoms in complex II. The mean distances are as follows: Cd-Br, 2.526(2) Å; Cd-I, 2.695 Å; and Cd-O, 2.243(8) Å in I and 2.210(4) Å in II. The L ¹ and L ligands in complexes I and II adopt an S-shaped conformation.     

Crystal and molecular structures of (1,3,4-thiadiazolyl-2)aminodipropionic and (5-methyl-1,3,4-thiadiazolyl-2)aminodipropionic acids

Crystal structures of (1,3,4-thiadiazolyl-2)aminodipropionic (I) and (5-methyl-1,3,4-thiadiazolyl-2) aminodipropionic (II) acids are determined [R = 0.0363 and 0.0529 for 2706 and 1614 reflections with I > 2σ(I) for I and II, respectively]. The similarity and distinctions in the hydrogen-bond systems and molecular-packing motifs of crystals I and II are discussed.     

Crystal structures and properties of isomers of 3,5-dinitro-(4-acetylphenyl)aminobenzoyl (p-bromophenyl)amide

The para and ortho isomers of 3,5-dinitro-(4-acetylphenyl)aminobenzoyl (p-bromophenyl)amide (I and II, respectively) are synthesized, and their physicochemical properties and structure are investigated. The para isomer I has a higher melting temperature and is less soluble in organic solvents as compared to the ortho isomer II. The electronic absorption spectra indicate that absorption for molecule I occurs at longer wavelengths than for molecule II. A correlation between the physicochemical properties and the crystal structures of compounds I and II is revealed. Crystals I · 0.5C₆H₆ are triclinic; the unit cell parameters are a = 11.760(2) Å, b = 13.958(3) Å, c = 15.012(3) Å, α = 108.01(2)°, β = 103.95(1)°, γ = 92.00(2)°, V = 2258.3(8) ų, space group $P\bar 1$ , and Z = 4. Crystals II are monoclinic; the unit cell parameters are a = 9.302(2) Å, b = 16.380(3) Å, c = 13.480(3) Å, β = 100.09(3)°, V = 2022.1(7) ų, space group P2₁/c, and Z = 4. Structures I · 0.5C₆H₆ and II are characterized by intramolecular and intermolecular hydrogen bonds.     

Crystal structures of cesium and dimethylammonium cupradecaborates, Cs[CuB10H10] and (CH3)2 NH2[CuB10H10]

The crystal structures of Cs[CuB₁₀H₁₀] (I) and (CH₃)₂NH₂[CuB₁₀H₁₀] (II) are studied (R = 0.0398 and 0.0510 for 1225 and 2728 observed reflections in I and II, respectively). Crystals I and II are built of [(CuB₁₀H₁₀)^?]∞ anionic chains and cations. The distorted tetrahedral coordination of the Cu⁺ ions is formed by four pairs of B-H atoms from two polyhedral anions. The Cu-B bond lengths in I and II are 2.159–2.287(6) and 2.130–2.285(9) Å, respectively. The coordination of the Cu⁺ ions in II includes only edges between apical and equatorial vertices of the anions. In I, both the edges of the apical belt and those between two equatorial vertices are involved in coordination. The ability of the B₁₀H ₁₀ ^2? anion to coordinate metals by the equatorial edge is established for the first time.     

Synthesis, crystal structure and DFT studies of N-(4-acetyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide

The title compound N-(4-acetyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazol-2-yl)acetamide (III) was obtained from the reaction of 2-(propan-2-ylidene)hydrazinecarbothioamide (II) with acetic anhydride instead of formation of the desired thiosemcarbazide derivative of Meldrum acid. The structures of II and III were established by elemental analysis, IR, NMR, Mass and X-ray crystallographic studies. II crystallizes in triclinic system, sp. gr. $P - \bar 1$ Z = 2; III crystallizes in the monoclinic system, sp. gr. P2₁/c, Z = 8. Density functional theory (DFT) calculations have been carried out for III. ¹H and ¹³C NMR of III has been calculated and correlated with experimental results.     

Crystal structures of mixed compounds Cu(2)Gly(D-Ser)(L-Ser)2 and Cu(2)Gly 3(L-Ser)

-The crystal structures of mixed coordination compounds, Cu(2)Gly(D-Ser)(L-Ser)₂(I) and Cu(2)Gly ₃(L-Ser)(II), which contain the amino acid residues of glycine (Gly) and serine (Ser) in the 1: 3 and 3: 1 ratio, respectively, are studied by electron diffraction. Crystals I and II are triclinic, Z = 1, and space group P1. For I, a = 8.96(2) Å, b = 9.66(2) Å, c = 5.07(2) Å, α = β = 90°, and γ = 92.8(3)°. For II, a = 8.37(2) Å, b = 9.65(2) Å, c = 5.06(2) Å, α = β = 90°, and γ = 92.8(3)°. Compounds I and II have layered structures that are based on the CuGly(L-Ser) fragment. Structures I and II differ mainly in their interlayer spacing and configuration of the interlayer space.     

CO replacement in Ru3(CO)12 by 2,3-bis(diphenylphosphino)maleic anhydride (bma). X-ray structures of Ru3(CO)10(bma)·H2O and

Thermolysis of Ru₃(CO)₁₂ with 2,3-bis(diphenylphosphino)maleic anhydride (bma) in toluene solution gives the new compounds Ru₃(CO)₁₀(bma) (2), Ru₂(CO)₆(bma) (3), and (4). All compounds have been isolated and characterized in solution by IR and³¹P NMR spectroscopy. The solid-state structures of2, as the monohydrate, and4 were established by X-ray crystallography. Ru₃(CO)₁₀(bma)·H₂O crystallizes in the monoclinic space groupC2/c,a=12.741(2) Å,b=19.548(2) Å,c=32.973(4) Å, β=96.847(9)°,V=8154(2) ų,Z=8,d _calc=1.740 g cm^?3;R=0.046,R _w =0.051 for 2541 observed reflections withl>3σ(l). The bma ligand in2 is bound to the triruthenium frame in a bridging fashion, with equatorially disposed PPh₂ groups. The X-ray structure of2 reveals an extreme twisting of the maleic anhydride ring away from the plane defined by the plane of the three ruthenium atoms, along with a significant lengthening of the maleic anhydride C=C π bond. crystallizes in the monoclinic space groupP2₁/c,a=9.3113(5) Å,b=18.164(1) Å,c=20.097(1) Å, β-102.021(4)°,V=3324.5(3) ų,Z=4,d _calc=1.671 g cm^?3;R=0.024,R _w =0.030 for 3499 observed reflections withl>3σ(l). The presence of the μ₂ moiety and P?C (maleic anhydride) bond cleavage attendant in the formation of4 are confirmed by X-ray analysis. The relationship of the compounds3 and4 to the dimeric compounds Ru₂(CO)₆(bpcd) and [where bpcd=4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione] is discussed. Independent studies dealing with Ru₃(CO)₁₀(bma) (bridging isomer) have shown that cluster2 is stable in toluene solution at elevated temperature and does not afford compounds3 and4, suggesting the intermediacy of the putative chelating isomer of Ru₃(CO)₁₀(bma) (1) as the source of3 and4.     

X-ray structural investigation of paramagnetic molecular compound of 2,5,9,12-tetramethyl-1,8-cis-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate,trans-diaquo-2,5,9,12-eramehyl-1,8-trans-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate,and water 2[cis-C14H28N4Ni](ClO4)2·[trans-C14H28N4Ni· 2H2O](ClO4)2·2H2O

The structure of molecular compoundI (2IA·IB·2H₂O), whereIA is a square-planar 2(e),5,9(a),12-tetramethyl-1,8-cis-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate andIB is an octahedraltrans-diaquo-2(e),5,9(e),12-tetramethyl-1,8-trans-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorate has been investigated by X-ray diffractometric methods. Compound I crystallizes in an orthorhombic system, space groupPbca, Z=12,a=26.321(3),b=19.919(2),c=13.306(1) Å. The structure was solved by the heavy-atom method followed by a series of Fourier syntheses and refined by full-matrix least-squares to giveR=0.060 (for 3757 independent reflections). Conformations were ascribed to chelate rings and to the macrocyclic rings ofIA andIB, and the results were compared with those of some known 1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) complexes. The relative configurations were found 1RS,2SR,8RS,9RS (a racemate) forIA and 1R,2S,8S,9R (ameso-form) forIB. They differ each from the other by configuration on one nitrogen centre (N-epimeric compounds).     

Five-coordinate Co(II) complexes with nitrilotriacetic acid: Crystal structures of Ca[Co(Nta)X] · nH2O (X − = Cl, Br, or NCS)

The synthesis and X-ray diffraction study of three Ca[Co(Nta)X] · nH₂O complexes [X ^? = Cl, n = 2.3 (I); X ^? = Br, n = 2 (II); and X ^? = NCS, n = 2 (III)] are performed. The main structural units of crystals I–III are the [CoX(Nta)]^2? anionic complexes and hydrated Ca²⁺ cations. The anionic complexes have similar structures. The coordination of the Co²⁺ atom in the shape of a trigonal bipyramid is formed by N + 3O atoms of the Nta ^3? ligand and the X ^? anion in the trans position with respect to N. In structures I–III, the Co-O and Co-N bond lengths lie in the ranges 1.998–2.032 and 2.186–2.201 Å, respectively. The Co-X bond lengths are 2.294 (I), 2.436 and 2.445 (II), and 1.982 Å (III). The environments of the Ca²⁺ cations include oxygen atoms of one or two water molecules and six or seven O(Nta) atoms with the coordination number of 9 in I or 8 in II and III. The Ca-O(Nta) bonds form a three-dimensional framework in I or layers in II and III. Water molecules are involved in the hydrogen bonds O(w)-H···O(Nta), O(w)-H···X, and O(w)-H···O(w). Structural data for crystals I–III are deposited with the Cambridge Structural Database (CCDC nos. 287 814–287 816).     

Molecular and crystal structures of dibenzenehemiporphyrazine complexes with dimethylformamide

The crystal structures of the 1: 1 and 1: 2 complexes between dibenzenehemiporphyrazine (I) and dimethylformamide (compounds II and III, respectively) are determined by X-ray diffraction. In both compounds, the macrocycle has a saddlelike shape. In III, the conformation of the macrocycle approximates the C _2v symmetry, which agrees closely with the results of quantum-chemical calculations for isolated molecule I and complex II. The ring conformation in crystal II is distorted under the effect of intermolecular interactions, as is evidenced by short intermolecular contacts. The complexes are stabilized by intermolecular N-H?O and C-H?O hydrogen bonds between the hydrogen atoms situated inside the cavity of the macrocycle and the oxygen atoms of the dimethylformamide molecules.     

Crystal and molecular structures of three ketoximes: (E)-O-hexanoyl phenyl 2-pyridyl ketone oxime (C18H20N2O2), (E)-O-octanoyl phenyl 2-pyridyl ketone oxime (C20H24N2O2), (E)-O-myristoyl phenyl 2-pyridyl ketone oxime (C26H38N2O2)

The crystal structures of the three title compounds have been determined by the X-ray structure analysis. The molecule of (E)-O-hexanoyl phenyl 2-pyridyl ketone oxime1 has an anti form at the N-O-C-C ester linkage, while the molecules of (E)-O-octanoyl phenyl 2-pyridyl ketone oxime2 and (E)-O-myristoyl phenyl 2-pyridyl ketone oxime 3 each have a syn form. Compounds2 and3 are crystallized in isomorphic bilayer structures, in which alkyl chains are packed in an antiparallel arrangement.     

X-ray structure investigation of 1-acetoxy-1-cyano-2-naphthylethylene and 1,1-dicyano-2-naphthylethylene

The crystal structures of 1-acetoxy-1-cyano-2-naphthylethylene (I) and 1,1-dicyano-2-naphthylethylene (II) are determined by X-ray structure analysis. Crystals I are monoclinic; at 25° C, the unit cell parameters are as follows: a = 17.308(6) Å, b = 4.507(1) Å, c = 17.845(5) Å, β = 107.90(2)°, V = 1324.7(7) ų, d _calcd = 1.260 g/cm³, Z = 4, and space group P2₁/n. Crystals II are monoclinic; at 25°C, the unit cell parameters are a = 3.827(1) Å, b = 15.784(4) Å, c = 17.226(2) Å, β = 91.22(2)°, V = 1040.3(4) ų, d _calcd = 1.304 g/cm³, Z = 4, and space group P2₁/n. It is revealed that, in crystal structures of I and II, the molecular stacks characteristic of compounds of this series are formed through stacking contacts along the direction of the smallest lattice parameter.     

Molecular and crystal structures of p-heptyloxyphenyl p-hexyloxybenzoate and p-butyloxyphenyl p-heptyloxybenzoate: Mesophase design

Two aromatic esters with the formulas C₆H₁₃-O-C₆H₄-C(O)O-C₆H₄-O-C₇H₁₅ (1) and C₇H₁₅-O-C₆H₄-C(O)O-C₆H₄-O-C₄H₉ (2) belonging to nematic liquid-crystal compounds were studied by X-ray diffraction. Compound 1 crystallizes in two modifications: monoclinic (1-m) and triclinic (1-tr). The crystal packing of 1 and 2 is built from alternating loosely packed aliphatic regions and closely packed aromatic regions. In crystal structures 1-m and 2, the aromatic regions are linked into chains by hydrogen bonds with the participation of the carbonyl oxygen atom of the ester group and the C-H fragment of the benzene ring, but these hydrogen bonds in 1-m are much weaker than in 2. In 1-m there are π-stacking interactions between the molecules, resulting in the formation of centrosymmetric dimers with an interplanar distance of 3.45 Å. In 1-tr, the aromatic fragments form a herringbone packing motif favorable for a two-dimensional network of directional C-H...π-system interactions.     

Effect of the acid-base interactions in a solution on the composition of the coordination sphere of aluminum and gallium complexonates

Hydroxocomplexonate K₂[GaEdta(OH)] · 6H₂O (I) and nitronium salts BH⁺GaEdta · 4H₂O (II) and BH⁺AlEdta · 4H₂O (IV) are synthesized from aqueous solutions at pH 8, 6, and 7, respectively. AlHEdta(H₂O) (III) is isolated from an acid solution (pH 1.5). Structures I, II, and IV are determined by single-crystal X-ray diffraction. The X-ray powder diffraction analysis of III has revealed that its crystals are not isostructural with those of similar complexes of other metals. Crystals I–IV are monoclinic. The unit cell parameters are a = 10.482(1), 15.735(4), 5.768(4), and 15.756(4) Å; b = 10.442(2), 12.511(2), 14.884(11), and 12.453(3) Å; c = 19.590(4), 17.330(5), 19.113(12), and 17.328(6) Å; β = 101.30(2)°, 104.54(2)°, 90.74(5)°, and 104.75(2)° for I–IV, respectively.     

Four solid-crystal forms of paraazoxyanisole and the thermodynamic relationships between them

It is shown that paraazoxyanisole has four solid-crystal forms. The heats and temperatures of melting and transition are related by the following five equations: Q _m(IV) = Q _m(II); Q _m(IV) = Q _m(I) + Q _m(III); T _m(IV) = T _m(III); T _tr(II–III) = T _m(I); and Q _tr(II–III) = Q _m(I), Q _m(SCIV) = 52.0 ± 0.3 kJ/mol. Earlier, similar relationships were established for the third homologue of paraazoxyanisole, Q _m[SCIV(C₃)] = 48.2 kJ/mol. It is found that for paraazoxyphenetole, Q _m[SCIV(C₂)] = 46.0 kJ/mol.