Synthesis, characterization and magnetic properties of four new organically templated metal sulfates [C5H14N2][M(II)(H2O)6](SO4)2, (M(II) = Mn, Fe, Co, Ni)

A series of novel organically templated metal sulfates, [C(5)H(14)N(2)][M(II)(H(2)O)(6)](SO(4))(2) with (M(II) = Mn (1), Fe (2), Co (3) and Ni (4)), have been successfully synthesized by slow evaporation and characterized by single-crystal X-ray diffraction as well as with infrared spectroscopy, thermogravimetric analysis and magnetic measurements. All compounds were prepared using a racemic source of the 2-methylpiperazine and they crystallized in the monoclinic systems, P2(1)/n for (1, 3) and P2(1)/c for (2,4). Crystal data are as follows: [C(5)H(14)N(2)][Mn(H(2)O)(6)](SO(4))(2), a = 6.6385(10) ?, b = 11.0448(2) ?, c = 12.6418(2) ?, β = 101.903(10)°, V = 906.98(3) ?(3), Z = 2; [C(5)H(14)N(2)][Fe(H(2)O)(6)](SO(4))(2), a = 10.9273(2) ?, b = 7.8620(10) ?, c = 11.7845(3) ?, β = 116.733(10)°, V = 904.20(3) ?(3), Z = 2; [C(5)H(14)N(2)][Co(H(2)O)(6)](SO(4))(2), a = 6.5710(2) ?, b = 10.9078(3) ?, c = 12.5518(3) ?, β = 101.547(2)°, V = 881.44(4) ?(3), Z = 2; [C(5)H(14)N(2)][Ni(H(2)O)(6)](SO(4))(2), a = 10.8328(2) ?, b = 7.8443(10) ?, c = 11.6790(2) ?, β = 116.826(10)°, V = 885.63(2) ?(3), Z = 2. The three-dimensional structure networks for these compounds consist of isolated [M(II)(H(2)O)(6)](2+) and [C(5)H(14)N(2)](2+) cations and (SO(4))(2-) anions linked by hydrogen-bonds only. The use of racemic 2-methylpiperazine results in crystallographic disorder of the amines and creation of inversion centers. The magnetic measurements indicate that the Mn complex (1) is paramagnetic, while compounds 2, 3 and 4, (M(II) = Fe, Co, Ni respectively) exhibit single ion anisotropy.     

The crystal structure of racemic and meso-diastereoisomers of aqua[2,6-bis(3-carboxy-1,2-dimethyl-2-azapropyl)pyridine]-Co(III) · Hexafluorophosphate · Di- and monohydrate,respectively

Synthesis of the pentadentate ligand 2,6-bis(3-carboxy-1,2-dimethyl-2-azapropyl)pyridine yields a mixture of the racemic and meso-isomers which it was difficult to separate by column chromatography. When the cationic Co(III)-complex of this ligand was crystallized with hexafluorophosphate as anion, two distinct crystalline forms were produced. The complex of the racemic ligand, 1 , has C₂ symmetry and is a dihydrate; a = 8.999(8), b = 12.047(6), c = 20.65(1) Å, orthorhombic, space group Peen,Z = 4, R = 0.074 for 1439 observed reflections. The complex of the meso-ligand, 2 , shows two independent molecules ( 2A and 2B ) per asymmetric unit, both monohydrates with a resolved disordered H₂O molecule in 2A ; a = 10.109(4), b = 12.835(2), c = 16.651(3) Å, α = 89.5(1)°, β = 84.7(3)°, γ = 88.6(3)°, triclinic, space group P1 , Z = 4, Rs = 0.054 for 4198 observed reflections. The coordination around the Co-atom is distorted octahedral in both complexes, with the coordinated H₂O molecule trans to the pyridine N-atom. In the racemic form of the complex, 1 , the pyridine ring is twisted about the Co-N(1) bond with respect to the plane defined by atoms Co, N(1), O(W1), N(2) and N(2P) by 17.2(2)°. In the meso-form of the complex, 2 , the CH₃ substituent C(8P) on atom C(4P), is now axial with respect to the 5-membered chelate ring. As a result of steric hinderance between atom O(1) and CH₃(8P), the pyridine ring has been displaced from the best mean-plane formed by atoms Co, O(W1), N(2) and N(2P). The principal axis of the pyridine ring C(3)…N(1), makes an angle of 14.1(1)° (mean) with this plane. At the same time the pyridine ring is twisted about axis C(3)…N(1) with respect to this plane by 19.7(1)° (mean).     

Two-dimensional supramolecular arrangements of enantiomers and racemic modification of 1,1'-binaphthyl-2,2'-dicarboxylic acid

Formation of adlayers of the optically active compound 1,1'-binaphthyl-2, 2'-dicarboxylic acid (BINAC) on iodine-modified Au (111) surfaces in perchloric acid was investigated by in situ scanning tunneling microscopy (STM). Highly ordered arrays formed on the surfaces via simple spontaneous adsorption from a solution of enantiomers or the racemic BINAC, in spite of the fact that BINAC has a three-dimensionally complex stereochemical structure. Adlayers of both enantiomers essentially shared the same enantiomorphous structure. Observed parameters of the rectangular unit cell lattice for arrays of both enantiomers of BINAC were a = 2.3 +/- 0.2 nm and b = 0.7 +/- 0.2 nm. On the other hand, racemic modification formed an entirely different adlayer, which consisted of an alternate alignment of the two enantiomers, with an oblique unit cell lattice with parameters of a = 1.2 +/- 0.2 nm, b = 0.8 +/- 0.1 nm, and 74 +/- 3 degrees . No domain composed of a single enantiomer was observed. The stronger hetero-intermolecular interactions of enantiomer couples led to the formation of an alternate arrangement in the array prepared by racemic modification.     

Synthesis and characterization of racemic mixture and meso isomers of bis(trans-2-aminocyclohexyl)aminepentaacetic acid and the stabilities of their Gd(III) complexes

The synthesis and characterization of two multidentate ligands, the racemic mixture and meso isomers of bis-(trans-2-aminocyclohexyl)aminepentaacetic acid, are described. Equilibrium constants for their Gd(III) complexes were determined by direct potentiometry. The formation constants (KML = [ML]/[M][L]) of Gd(III)-Cycyracemic in 0.10 M KCl at 25.0 degrees C is 10(20.71; that for the meso isomer is 10(20.42). The crystal structure of (1S,2S,1'S,2'S)-bis(trans-2-aminocyclohexyl)amine-N,N,N',N",N"-pentaacetic acid, penta-tert-butyl ester (C42H75N3O10), is reported. This compound crystallizes in the triclinic system with space group P1 with cell parameters a = 10.805(2) A, b = 11.382(2) A, c = 20.999(4) A, alpha = 91.41(3) degrees, beta = 98.23(3) degrees, gamma = 113.88(3) degrees, V = 2327.8(8) A3, Z = 2, Dx = 1.116 g mL-1. The results are compared to the crystal structures of the gadolinium complexes and the predictions derived from molecular mechanics.     

Synthesis and crystal structure (1,10-diaza-18-crown-6-N,N′,O,O′)dichloromanganese(II)

A new crystalline complex (1,10-diaza-18-crown-6-N,N′,O,O′)dichloromanganese(II) [MnCl₂(DA18C6)] (I) is synthesized and studied by single-crystal X-ray diffraction. The structure of compound I (space group P2₁/c, a = 11.827 Å, b = 7.580 Å, c = 19.715 Å, β = 98.76°, Z = 4) is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.026 for all 3055 independent measured reflections (CAD4 automated diffractometer, λMoK _α radiation). The [MnCl₂(DA18C6)] complex molecule in I is of the host-guest type: its Mn²⁺ cation is asymmetrically arranged in the cavity of the DA18C6 ligand and coordinated by its four heteroatoms, namely, the two N atoms and two O atoms, and by the two Cl^? anions. The coordination polyhedron of the Mn²⁺ cation (six-coordination) may be described as a distorted pentagonal bipyramid with one unfilled vertex or as a distorted square pyramid with one split vertex at the two O atoms of the DA18C6 ligand. The DA18C6 ligand in I has an unusual asymmetric conformation. The complex molecules in a crystal of I are linked by a pair of N-H···Cl intermolecular hydrogen bonds into centrosymmetric dimers.     

Crystal Structure and Spectroscopic Studies of Diphenylcarbazide Acetonitrile Solvate,(PhNHNH)_2C=O·CH_3CN

1INTRODUCTIONDiphenylcarbazideisanartificialelectrondonormaterialusedfrequentlyinanalyticalchemi-stryforcalorimetricdeterminationofchromiumandasensitivereagentformetalions(mercuryandcadmium)[1].Ithasvariousapplications,especiallyinthefieldsofbiophysicsandmicrobiology.Withthehelpofexogenouselectrondonors,diphenylcar-bazidephotointheactivatedsitesontheelectrontransferchainweredelineated[2].Diphenylcarbazideisalsoanartificialdonorduringchargeseparationinthephotochemicalreactions[3]andphotosy…     

Stereoselective formation of seven-coordinate titanium(IV) monomer and dimer complexes of ethylenebis(o-hydroxyphenyl)glycine

Reactions between the antitumor agent titanocene dichloride (Cp2TiCl2) and the hexadentate ligand N,N'-ethylenebis-(o-hydroxyphenylglycine) (H4ehpg) have been investigated in aqueous solution and the solid state. The racemic ligands give crystals of the monomer [Ti(ehpg)(H2O)] x (11/3)H2O (1), while the meso ligand gives the oxo-bridged dimer [[Ti(Hehpg)(H2O)]2O] x 13H2O (2). Complex 1 crystallizes in the monoclinic space group C2/c with a = 24.149(4) A, b = 14.143(3) A, c = 19.487(3) A, beta = 105.371(13) degrees, V = 6417.7(19) A3, Z = 12, and R(F) = 0.0499 for 4,428 independent reflections having I > 2sigma(I), and contains seven-coordinate pentagonal-bipyramidal TiIV with two axial phenolate ligands (Ti-O, 1.869(2) A). The pentagonal plane contains the two N-atoms at 2.210(2) A, two carboxylate O-atoms at 2.061(2) A, and a water molecule (Ti-OH2, 2.091(3) A). Complex 2 crystallizes as an oxygen-bridged dimer in the triclinic space group P-1 with a = 12.521(6) A, b = 14.085(7) A, c = 16.635(8) A, alpha = 80.93(2) degrees beta = 69.23(2) degrees, gamma = 64.33(2) degrees , V = 2472(2) A3, Z = 4, and R(F) = 0.0580 for 5956 independent reflections having I > 2sigma(I). Each seven-coordinate, pentagonal-bipyramidal TiIV has a bridging oxide and a phenolate as axial ligands. The pentagonal plane donors are H2O, two carboxylate O-atoms, and two NH groups, which form H-bonds to O-atoms both in the same half-molecule (O...N, 2.93-3.13 A) and in the other half-molecule (O...N, 2.73-2.75 A); the second phenoxyl group of each Hehpg ligand is protonated and not coordinated to TiIV, but H-bonds to a nearby amine proton (O...N, 2.73-2.75 A) from the same ligand and to a nearby H2O (O...O, 2.68 A). In contrast to all previously reported crystalline metal-EHPG complexes containing racemic ligands, in which the N(S,S)C(R,R) or N(R,R)C(S,S) form is present, complex 1 unexpectedly contains the N(S,S)C(S,S) and N(R,R)C(R,R) forms. This is attributed to the presence of ring strain in seven-coordinate TiIV complexes. Moreover, the rac ligands selectively form crystals of monomeric 1, while the meso ligand selectively forms crystals of the dimer 2 (N(R,R)C(R,S) or N(S,S)C(S,R)). Complexes 1 and 2 exhibit phenolate-to-TiIV charge-transfer bands near 387 nm, and 2D NMR studies indicate that the structures of 1 and 2 in solution are similar to those in the solid state. Complex 1 is stable over the pH range 1.0-7.0, while 2 is stable only between pH 2.5 and pH 5.5. Cp2TiCl2 reacts with EHPG at pH* 7.0 to give complex 1 with a t 1/2 of ca. 50 min (298 K), but complex 2 was not formed at this pH* value. At pH* 3.7, the reaction is very slow: 1 forms with a half-life of ca. 2.5 d, and 2 after ca. 1 week at ambient temperature. The relevance of these data to the possible role of serum transferrin as a mediator for the delivery of TiIV to tumor cells is discussed.     

Pi-pi stacking assisted binding of aromatic amino acids by copper(II)-aromatic diimine complexes. Effects of ring substituents on ternary complex stability

Ternary Cu(ii) complexes containing an aromatic diimine (DA = di(2-pyridylmethyl)amine (dpa), 4,4'-disubstituted 2,2'-bipyridine (Y(2)bpy; Y = H (bpy), Me, Cl, N(Et)(2), CONH(2) or COOEt) or 2,2'-bipyrimidine) and an aromatic amino acid (AA = l-phenylalanine (Phe), p-substituted phenylalanine (XPhe; X = NH(2), NO(2), F, Cl or Br), l-tyrosine (Tyr), l-tryptophan (Trp) or l-alanine (Ala)) were characterized by X-ray diffraction, spectroscopic and potentiometric measurements. The structures of [Cu(dpa)(Trp)]ClO(4).2H(2)O and [Cu((CONH(2))(2)bpy)(Phe)]ClO(4).H(2)O in the solid state were revealed to have intramolecular pi-pi interactions between the Cu(ii)-coordinated aromatic ring moiety, Cu(DA) (Mpi), and the side chain aromatic ring of the AA (Lpi). The intensities of Mpi-Lpi interactions were evaluated by the stability constants of the ternary Cu(ii) complexes determined at 25 degrees C and I = 0.1 M (KNO(3)), which revealed that the stability enhancement of the Cu(DA)(AA) systems due to the interactions is in the order (CONH(2))(2)bpy < bpy < Me(2)bpy < (Et(2)N)(2)bpy with respect to DA. The results indicate that the electron density of coordinated aromatic diimines influences the intensities of the stacking interactions in the Cu(DA)(AA) systems. The Mpi-Lpi interactions are also influenced by the substituents, X, of Lpi and are in linear relationship with their Hammett sigma(p) values with the exception of X = Cl and Br.     

First principle lattice energy calculations for enantiopure and racemic crystals of α-(trifluoromethyl)lactic acid: Is self-disproportionation of enantiomers controlled by thermodynamic stability of crystals?

The lattice energies for the enantiopure and racemic crystals of α-(trifluoromethyl)lactic acid were calculated by a combination of the DFT calculations with the periodic boundary condition and the MP2 calculations of the interactions with neighboring molecules. The lattice energies calculated for the two crystals (−16.56 and −17.35 kcal/mol, respectively) show that the racemic crystals are thermodynamically more stable, although the racemic crystals sublime faster than the enantiopure crystals. The calculations suggest that the relative thermodynamic stability is not the cause of the faster sublimation rate of the racemic crystals compared with the enantiopure crystals. Although the crystals have hydrogen-bonding networks, the dispersion interactions contribute to the lattice energies significantly. The MP2 calculations for the evaluation of the dispersion interactions with the neighboring molecules are important for an accurate evaluation of the lattice energies. The relative thermodynamic stability of the two crystals is not determined solely by the hydrogen bonds. The interactions with other neighboring molecules also play important roles in determining the relative stability. We demonstrate that the geometry optimization is essential for an accurate evaluation of the lattice energy by the first principle calculation. The interaction energies calculated using the structure by X-ray diffraction often have large errors.     

A chiral [2]catenane self-assembled from meso-macrocycles of palladium(II)

Reaction of trans-[PdX2(SMe2)2](X = Cl or Br) with the chiral ligand LL = 1,1'-binaphthyl-2,2'-(NHC(= O)-3-C5H4N)2 gave the [2]catenane complexes trans-[{(PdX2)2(micro-LL)2}2], which are formed by self-assembly from 4 units each of trans-PdX2 and LL. The catenation is favored by the formation of multiple hydrogen bonds between the constituent macrocycles (4 x NHClPd, 2 x NHO double bond C). If the ligand LL is racemic, each macrocycle trans-[(PdX2)2(micro-LL)2] is formed in the meso form trans-[(PdX2)2(micro-R-LL)(micro-S-LL)] but the resulting [2]catenane is chiral as a direct result of the catenation step. This is the first time that this form of chiral [2]catenane has been observed. The enantiomers of the [2]catenane further self-assemble in the crystalline form, through secondary intermolecular PdX bonding, to form a racemic infinite supramolecular polymer of [2]catenanes.     

Synthesis and Crystal Structure of an Inclusion Compound Mn(SCN)2(H2O)4(2C6H12N4

A mononuclear manganese complex Mn(SCN)2(H2O)4(2C6H12N4 (C14H32O4N10MnS2, C6H12N4 = hexamethylenetetramine) has been synthesized. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of tetragonal, space group P42/mnm with a = 9.5591(7), b = 9.5591(7), c = 13.8253(15) (A), V = 1263.31(19) (A)3, Z = 2, Mr = 523.56, Dc = 1.376 g/cm3, μ = 0.727 mm-1, F(000) = 550, Rint = 0.0302, T = 293(2) K, R = 0.0380 and wR = 0.1184 for 549 observed reflections with I > 2σ(I). In the crystal the manganese atom is six-coordinated by two nitrogen atoms from isothiocyanato anion and four oxygen atoms from water molecules, completing an octahedral geometry. Hexamethylenetetramine molecules are included in the lattice and connected to Mn(SCN)2(H2O)4 by hydrogen bonding and S...S interac- tions to form a three-dimensional supramolecular architecture.     

Magnetic ordering in iron tricyanomethanide

Magnetic susceptibility, heat capacity, and neutron diffraction studies of Fe[C(CN)(3)](2) reveal the existence of two magnetic phase transitions at T(N,I) = 2.45 K and T(N,II) = 1.85 K. Between 1.85 and 2.45 K, the magnetic ordering is incommensurate with a temperature-dependent propagation vector (k(I,x) 0 0), k(I,x) = 0.525-0.540. In zero magnetic field, below 1.85 K the ordered structure is described by the propagation vector k(II) = ((1/2) 0 (1/2)), i.e., a doubling of the unit cell along the a and c directions of the orthorhombic lattice. The ordered moments of 3.4(1) and 3.2(1) micro(B), respectively, are aligned approximately parallel to the principal axis of the elongated Fe coordination octahedron. At T < T(N,II), application of an external magnetic field of about 18 kOe destroys the commensurate phase and the incommensurate phase is established. The latter phase is stable in fields up to about 40 kOe. The magnetic ordering of Fe[C(CN)(3)](2) is discussed in terms of the 2D triangular topology of the lattice, producing partial frustration, and in comparison with the behavior of other compounds of the series M[C(CN)(3)](2), where M is a 3d transition metal.     

Structure, magnetism and optical properties of achiral and chiral two-dimensional oxalate-bridged anionic networks with symmetric and asymmetric ammonium cations

A series of two-dimensional (2D) oxalate-based compounds, namely [N(n-C4H9)4][M(II)Cr(III)(ox)3] (M(II) = Mn, Fe; ox = C2O4(2-)) and [N(C2H5)(n-C3H7)(n-C4H9)(n-C5H11)][M(II)M(III)(ox)(3)] ((M(II), M(III)) =(Mn, Cr), (Fe, Cr), (Mn, Fe)) were synthesised starting from racemic tris(oxalato)metalate: rac-[M(III)(ox)3]3- (M(III) = Cr, Fe). For Cr(III), the synthesis has been undertaken starting from resolved (Delta)- or (Lambda)-[Cr(III)(ox)3]3-. The natural circular dichroism measurements assess the enantioselectivity of the synthesis. X-Ray powder diffraction analysis has revealed that, when racemic reagents are used to synthesise Mn(II) containing compounds, a R3c achiral space group is found. In contrast a P6(3) chiral space group is found when starting from (Delta)- or (Lambda)-[Cr(III)(ox)3]3-. Surprisingly, whatever the optical purity of the starting building block, all Fe(II) containing compounds crystallise in the P6(3) chiral space group. The magnetic properties of the synthesised compounds confirm that these compounds are ferromagnets for M(III)= Cr. For M(II)= Mn, Theta ranges between 9 and 11 K and T(c) equals 6 K. For M(II)= Fe, Theta ranges between 14 and 16 K and Tc between 11 and 12 K. [N(C2H5)(n-C3H7)(n-C4H9)(n-C5H11)][Mn(II)Fe(III)(ox)3] is an antiferromagnet with Theta = - 107 K and T(N) = 29 K.     

Planar-chiral metal complexes comprised of square-planar metal and achiral tetradentate ligands: design, optical resolution, and thermodynamics

Planar-chiral palladium complexes {[[N,N'-[1,4-butanediylbis(oxy-7,1-naphthalenediyl)]bis(2-pyridinecarboxamidato)](2-)-κN(1),κN(1)',κN(2),κN(2)']palladium (PdL(4)) and [[2,2'-[1,4-butanediylbis[[(oxy-7,1-naphthalenediyl)imino]methyl]]dipyrrolato](2-)-κN(1),κN(1)',κN(2),κN(2)']palladium (PdL(5))} were synthesized from achiral tetradentate ligands N,N'-[1,4-butanediylbis(oxy-7,1-naphthalenediyl)]bis(2-pyridinecarboxamide) (H(2)L(4)) and N,N'-bis[(1H-pyrrol-2-yl)methylidene]-7,7'-(1,4-butanediyldioxy)bis(1-naphthalenamine) (H(2)L(5)) bearing two dissymmetric bidentate units at both ends and a Pd(II) ion, respectively. The palladium complexes were crystallized in the monoclinic space group P2(1)/n with the unit cell parameters a = 16.5464(6) ?, b = 11.3534(4) ?, c = 17.6697(7) ?, β = 115.5300(10)°, and Z = 4 for PdL(4) and a = 17.2271(8) ?, b = 10.1016(5) ?, c = 17.9361(9) ?, β = 105.6310(10)°, and Z = 4 for PdL(5). The planar-chiral structures of PdL(4) and PdL(5) were confirmed by single-crystal X-ray analyses, resulting in the fact that the crystals were racemic mixtures. The racemic mixtures were successfully resolved by using chiral high-performance liquid-chromatography techniques. Racemizations of the complexes were found to be drastically dependent on the arrangement of the charged or uncharged metal-binding N atoms of the ligands.     

Homochiral conglomerates and racemic crystals in two dimensions: tartaric acid on Cu(110)

Two-dimensional lattice structures formed by racemic tartaric acid on a single crystalline Cu(110) surface have been studied and compared with the enantiopure lattices. At low coverage, the doubly deprotonated bitartrate species is separated into two-dimensional conglomerates showing opposite enantiomorphism. At higher coverage, however, a singly deprotonated monotartrate species forms a heterochiral, racemic crystal lattice. While the enantioseparated bitartrate system undergoes decomposition at the same temperature as the enantiopure system, the racemic monotartrate lattice has a lower thermal stability than the enantiopure lattice of identical periodicity and surface density. At monolayer saturation coverage, the pure enantiomers form a denser lattice than the racemate. This is in contrast to the three-dimensional tartaric acid crystals, where the racemate crystallizes in a lattice of higher density, which is also more thermally stable than the enantiopure tartaric acid crystals.     

Synthesis and Crystal Structure of 2,2＇-Dihydroxy-[1,1＇]binaphthalenyl-3,3＇-bis-hydroxamic Acids

The first synthesis and structural characterization by X-ray crystallography of racemic 2,2'-dihydroxy-[1,1']binaphthalenyl-3,3'-bis-hydroxamic acids were reported.The com-pound(C28H30N4O8,Mr = 550.56) crystallizes in orthorhombic system,Fdd2 space group with a = 13.055(3),b = 34.871(7),c = 12.570(3) ,V = 5722(2) 3,Z = 8,Dc = 1.278 g/cm3,λ = 0.71073 ,μ(MoKα) = 0.095 mm-1,F(000) = 2320,S = 1.021,R = 0.0349 and wR = 0.0802 for 1757 observed reflections with I > 2σ(I).The N-H and O atom are involved in two-dimensional intermolecular hydrogen bond nets,which further stabilize the structure.     

Kristall- und Molekülstruktur von 6-Ethoxy-12,12-dimethyldibenzo[d,g]-1,3,2,6-dioxaphosphasilocin-6-oxid

Synthesis and Crystal Structure of the Bis(amidinatochelate) Complex ClSb[Ph? C(NSiMe₃)₂]₂ The antimony(III) amidinato complex ClSb[Ph? C(NSiMe₃)₂]₂ was obtained by the reaction of antimony trichloride and N,N,N′-tris(trimethylsilyl)benzamidine in dichloromethane in form of pale-yellow, moisture sensitive crystals. X-ray crystal structure determinations were performed at 20°C and at ?93°C. Crystal data at 20°C: space group P1 , Z = 2, a = 1160.3(2), b = 1305.4(2), c = 1336.5(2) pm, α = 68.32(1), β = 79.79(1), γ = 71.47(1)°; at ?93°C the lattice vectors are 1.20 to 0.85% shorter. In the molecule two Ph? C(NSiMe₃)₂ groups are attached with their N atoms in a chelate manner to the Sb atom. Together with the Cl atom they form an irregular coordination polyhedron about the Sb atom with a stereochemically strongly effective lone electron pair. The SiMe₃ groups show considerable twisting vibrations about the N? Si axes even at ?93°C.     

Synthesis,Crystal Structure and Antifungal Activity of N-（Pyridine-2-methyl）-2-（4- chlorophenyl）-3-methylbutanamide

A novel compound N-（pyridine-2-methyl）-2-（4-chlorophenyl）-3-methylbutanamide, a racemic compound, has been synthesized with 2-（4-chlorophenyl）-3-methylbutyric acid and pyridin- 2-methylanamine as the raw materials, and its crystal structure （C17H19C1N2O, Mr = 302.79） was determined by single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/n with a = 9.624（9）, b = 23.14（2）, c = 15.626（15）A, β = 106.199（14）°, V = 3342（5） A^3, Z = 8, Dc = 1.204 g/cm^3,μ = 0.23 mm^-1, F（000） = 1280, S = 1.032, R = 0.0681 and wR = 0.1508 for 6513 unique reflections （Rint = 0.0421） with 3375 observed ones. In the crystal structure, there are some intermolecular hydrogen bonds which stabilize the crystal structure. The preliminary bioassay shows that the title compound exhibits good antifungal activity against Botrytis cinerea, Gibberella zeae, Dothiorella gregaria and Colletotrichum gossypii.     

Synthesis,Spectroscopic Properties and Crystal Structure of (C4N2H12)2Zr(C2O4)4·H2O

The title compound (C4N2H12)2Zr(C2O4)4·H2O 1 was synthesized by the reaction of ZrOCl2·8H2O, H2C2O4·2H2O and piperazinium in aqueous solution. Single-crystal X-ray analysis has revealed that compound 1 (C16H26N4O17Zr, Mr = 637.63) crystallizes in the monoclinic system, space group P21/c with a = 9.0425(3), b = 13.3844(3), c = 19.1191(5)A, β = 98.365(1)o, V = 2289.34(11) A3, Z = 4, Dc = 1.850 g/cm3, F(000) = 1304, μ = 0.577 mm-1, the final R = 0.0240 and wR = 0.0628 for 4386 observed reflections with I > 2σ(I). X-ray crystal-structure analysis suggests that compound 1 consists of [Zr(C2O4)4]4- anion and two protonated piperazinium cations. The anions are linked through hydrogen bonds of piperazinium. FT-IR and Raman spectra clearly show the existence of oxalate groups in the crystal lattice.     

Stepwise neutral-ionic phase transitions in a covalently bonded donor/acceptor chain compound

Neutral (N)-ionic (I) transitions in organic donor (D)/acceptor (A) charge-transfer complexes are intriguing because a 'reservoir of functions' is available. For systematically controlling N-I transitions, tuning the ionization potential of D and the electron affinity of A is extremely important. However, the effect of Coulomb interactions, which likely causes a number of charge-gap states at once in a system bringing about stepwise transitions, is a long-standing mystery. Here, we show definite evidence for stepwise N-I transitions caused by contributions from anisotropic interchain Coulomb interactions in a metal-complex-based covalently bonded DA chain compound, [Ru(2)(2,3,5,6-F(4)PhCO(2))(4)(DMDCNQI)]·2(p-xylene) (1; 2,3,5,6-F(4)PhCO(2)(-) = 2,3,5,6-tetrafluorobenzoate; DMDCNQI = 2,5-dimethyl-N,N'-dicyanoquinonediimine), where the [Ru(2)(II,II)(2,3,5,6-F(4)PhCO(2))(4)] moiety has a paddlewheel diruthenium(II,II) motif with a Ru-Ru bond. An intermediate-temperature phase involving self-organized N and I chains was observed in the temperature range between 210 K (= T(2)) and 270 K (= T(1)) with N phase at T > T(1) and I phase at T < T(2). Accompanying the charge transitions, the spin-ground states as well as the ferrimagnetic ordering in the I phase vary. The stepwise feature of the N-I transition with a highly sensitive magnetic response should bring about new dynamical functionalities associated with charge, spin, and lattice.