LaZnB(5)O(10), the first lanthanum zinc borate.

Lanthanum zinc penta-borate, LaZnB(5)O(10), was synthesized by flux-supported solid-state reaction. It is a member of the LnMB(5)O(10) (Ln = rare earth ion and M = divalent metal ion) structure type. The crystal shows a three-dimensional structure constructed from two-dimensional {[B(5)O(10)](5-)}(n) layers with the lanthanum (coordination number nine) and zinc (coordination number six) ions filling in the inter-layers.

N-(4-Chloro-phen-yl)-2-de-oxy-α-l-ribo-pyran-osylamine.

In the crystal structure of the title compound, C(11)H(14)ClNO(3), inter-molecular hydrogen bonds link mol-ecules in the ab plane, forming layers that stack along the c axis.

Poly[mu2-(N-hydroxypyridine-2-carboxamidine)-mu2-nitrato-silver(I)].

In the title complex, [Ag(NO3)(C6H7N3O)]n or [Ag(NO3)(pyaoxH2)] (pyaoxH2 is N-hydroxypyridine-2-carboxamidine), the Ag+ ion is bridged by the pyaoxH2 ligands and nitrate anions, giving rise to a two-dimensional molecular structure. Each pyaoxH2 ligand coordinates to two Ag+ ions using its pyridyl and carboxamidine N atoms, and the OH and the NH2 groups are uncoordinated. Each nitrate anion uses two O atoms to coordinate to two Ag+ ions. The Ag...Ag separation via the pyaoxH2 bridge is 2.869 (1) A, markedly shorter than that of 6.452 (1) A via the nitrate bridge. The two-dimensional structure is fishscale-like, and can be described as pyaoxH2-bridged Ag2 nodes that are further linked by nitrate anions. Hydrogen bonding between the amidine groups and the nitrate O atoms connects adjacent layers into a three-dimensional network.

3,4-Dicyano-phenyl 2,3,4,6-tetra-O-acetyl-α-d-glucopyran-oside.

The title compound, C(22)H(22)N(2)O(10), was prepared by the glycosidation method through nitrite displacement on substituted nitro-phthalonitrile. The mol-ecule contains a benzene ring, two nitrile groups and an acetyl-protected d-glucose fragment which adopts a chair conformation. The absolute configuration was determined by the use of d-glucose as starting material. All substituents of the protected sugar are in equatorial positions, with the exclusive presence of the α-anomer. The crystal packing is stabilized by C-H⋯O and C-H⋯N hydrogen-bonding inter-actions.

1-(2-Methyl-5-phenyl-3-thienyl)-2-(3-methyl-5-phenyl-2-thienyl)-3,3,4,4,5,5-hexafluorocyclopent-1-ene: a novel photochromic hybrid diarylethene.

The title compound, C27H18F6S2, a novel photochromic hybrid diarylethene derivative containing 2- and 3-thienyl substituents, is one of the most promising photochromic candidates with shorter wavelength for optical storage and other optoelectronic devices. In the crystal structure, the molecule adopts a photoactive antiparallel conformation. The distance between the two reactive C atoms, i.e. the ring C atoms to which the methyl groups are attached, is 3.430 (4) A. The dihedral angles between the thienyl and adjacent phenyl rings are 26.8 (2) and 33.98 (9) degrees.

1,2-Bis[5-(1,3-dioxolan-2-yl)-2-ethyl-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene, a photochromic dithienylethene.

The title compound, C23H22F6O4S2, a photochromic dithienylethene, is a promising material for optical storage and other optoelectrical devices. The molecule adopts a photoactive antiparallel conformation in the crystalline state. The distance between the two reactive C atoms which are involved in potential ring closure is 3.829 (4) A. The dihedral angles between the central cyclopentene ring and the adjacent thiophene rings are 55.38 (7) and 54.81 (9) degrees. The colourless crystals turn magenta when exposed to UV radiation and the process is reversible.

Assembly of azido- or cyano-bridged binuclear complexes containing the bulky [Mn(phen)2]2+ building block: syntheses, crystal structures, and magnetic properties.

Two new cyano-bridged heterobinuclear complexes, [Mn(II)(phen)2Cl][Fe(III)(bpb)(CN)2] x 0.5CH3CH2OH x 1.5H2O (1) and [Mn(II)(phen)2Cl][Cr(III)(bpb)(CN)2] x 2H2O (2) [phen = 1,10-phenanthroline; bpb(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate], and four novel azido-bridged Mn(II) dimeric complexes, [Mn2(phen)4(mu(1,1)-N3)2][M(III)(bpb)(CN)2]2 x H2O [M = Fe (3), Cr (4), Co (5)] and [Mn2(phen)4(mu(1,3)-N3)(N3)2]BPh4 x 0.5H2O (6), have been synthesized and characterized by single-crystal X-ray diffraction analysis and magnetic studies. Complexes 1 and 2 comprise [Mn(phen)2Cl]+ and [M(bpb)(CN)2]- units connected by one cyano ligand of [M(bpb)(CN)2]-. Complexes 3-5 are doubly end-on (EO) azido-bridged Mn(II) binuclear complexes with two [M(bpb)(CN)2]- molecules acting as charge-compensating anions. However, the Mn(II) ions in complex 6 are linked by a single end-to-end (EE) azido bridging ligand with one large free BPh4(-) group as the charge-balancing anion. The magnetic coupling between Mn(II) and Fe(III) or Cr(III) in complexes 1 and 2 was found to be antiferromagnetic with J(MnFe) = -2.68(3) cm(-1) and J(MnCr) = -4.55(1) cm(-1) on the basis of the Hamiltonian H = -JS(Mn)S(M) (M = Fe or Cr). The magnetic interactions between two Mn(II) ions in 3-5 are ferromagnetic in nature with the magnetic coupling constants of 1.15(3), 1.05(2), and 1.27(2) cm(-1) (H = -JS(Mn1)S(Mn2)), respectively. The single EE azido-bridged dimeric complex 6 manifests antiferromagnetic interaction with J = -2.29(4) cm(-1) (H = -JS(Mn1)S(Mn2)). Magneto-structural correlationship on the EO azido-bridged Mn(II) dimers has been investigated.

[Fe(bpb)(CN)2]- as a versatile building block for the design of novel low-dimensional heterobimetallic systems: synthesis, crystal structures, and magnetic properties of cyano-bridged Fe(III)-Ni(II) complexes [(bpb)(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate].

A dicyano-containing [Fe(bpb)(CN)2]- building block has been employed for the synthesis of cyano-bridged heterometallic Ni(II)-Fe(III) complexes. The presence of steric bpb(2-) ligand around the iron ion results in the formation of low-dimensional species: five are neutral NiFe2 trimers and three are one-dimensional (1D). The structure of the 1D complexes consists of alternating [NiL]2+ and [Fe(bpb)(CN)2]- generating a cyano-bridged cationic polymeric chain and the perchlorate as the counteranion. In all complexes, the coordination geometry of the nickel ions is approximately octahedral with the cyano nitrogen atoms at the trans positions. Magnetic studies of seven complexes show the presence of ferromagnetic interaction between the metal ions through the cyano bridges. Variable temperature magnetic susceptibility investigations of the trimeric complexes yield the following J(NiFe) values (based on the spin exchange Hamiltonian H = -2J(NiFe) S(Ni) (S(Fe(1)) + S(Fe(2))): J(NiFe) = 6.40(5), 7.8(1), 8.9(2), and 6.03(4) cm(-1), respectively. The study of the magneto-structural correlation reveals that the cyanide-bridging bond angle is related to the strength of magnetic exchange coupling: the larger the Ni-N[triple bond]C bond angle, the stronger the Ni- - -Fe magnetic interaction. One 1D complex exhibits long-range antiferromagnetic ordering with T(N) = 3.5 K. Below T(N) (1.82 K), a metamagnetic behavior was observed with the critical field of approximately 6 kOe. The present research shows that the [Fe(bpb)(CN)2]- building block is a good candidate for the construction of low-dimensional magnetic materials.

Synthesis, crystal structure, and magnetic properties of oxime-bridged polynuclear Ni(II) and Cu(II) complexes.

Two new polynuclear complexes [Ni6(amox)6(mu6-O)(mu3-OH)2](Cl2).6H2O and [Cu3(amox)3(mu3-OH)(mu3-Cl)](ClO4).4H2O (amox- = anion of 4-amino-4-methyl-2-pentanone oxime) have been synthesized and characterized structurally and magnetically. The Ni(II) complex contains a novel Chinese-lantern-like Ni6 cage centered by an oxo ion. It contains the nearest octahedral Ni(II)...Ni(II) separation (<2.8 A) and exhibits strong antiferromagnetic properties. The Cu(II) complex has a cyclic trinuclear copper(II) core bridged by both mu3-OH(-) and mu3-Cl(-) ions. The magnetic susceptibilities of both antiferromagnetic complexes were fitted by using approximate models.

A novel thiocyanate-bridged one-dimensional chain complex: [Cu(NCS)2(Hambi)] (Hambi is 2-aminomethyl-1H-benzimidazole).

Using 2-aminomethyl-1H-benzimidazole as the ligand, a new thiocyanate-bridged copper(II) complex, namely bis(2-aminomethyl-1H-benzimidazole-kappa(2)N(2),N(3))dithiocyanatocopper(II),[Cu(NCS)(2)(C(8)H(9)N(3))], has been synthesized and structurally characterized. The Cu atom is five-coordinated and exhibits a distorted square-pyramidal geometry. The thiocyanate ions (NCS(-)) act as either bridging or terminal ligands. The bridging NCS(-) ligands connect neighboring Cu atoms, constructing chains, while the terminal NCS(-) ligands form hydrogen bonds with amine H atoms, leading to a complicated network.

Cyano-bridged 2D Cu(II)-Cr(III) coordination polymers: structural evidence for formation of a polymeric macrocyclic metallic compound.

Two unique cyano-bridged 2D coordination polymers have been synthesized and characterized structurally and magnetically. The complexes contain two polyaza Cu(II) units and one novel macromolecular Cu(II) moiety, which have been synthesized via one-pot metal template condensation reactions involving ethylenediamine (en) and formaldehyde. Self-assembly of the polyaza Cu(II) mixture with [Cr(CN)(6)](3)(-) gave rise to two layered complexes. One complex contains unprecedented covalently linked polymeric Cu(II) chains and cyano-bridged Cu(II)(-)Cr(III) coordination chains, which are interwoven to form a novel layer. The other complex shows intriguing encapsulation of [Cr(CN)(6)](3)(-) anions. Intermetallic ferromagnetic coupling is operative within the bridged 2D layer. The magnetic susceptibilities of both complexes were simulated using approximate models.

3,3,4,4,5,5-Hexafluoro-1,2-bis(5-hydroxymethyl-2-methyl-3-thienyl)cyclopent-1-ene.

The title compound, C(17)H(14)F(6)O(2)S(2), a photochromic diarylethene, is one of the most promising materials for optical memories and other optoelectronic devices. The hexafluorocyclopentene group and the two thiophene rings are all planar, and the dihedral angles between the cyclopentene ring and the adjacent thiophene rings are 46.4 (1) and 49.5 (1) degrees.

Displaced pi-pi stacking and hydrogen bonds in 3-bromo-N-(2-hydroxy-1,1-dimethylethyl)benzamide.

The molecules of the title compound, C11H14BrNO2, are assembled into a two-dimensional network by a combination of hydrogen bonds and stacking interactions. The phenyl rings are stacked along the c direction by displaced pi-pi interactions, forming a lipophilic layer. The aliphatic amide residues are interconnected along [100] by O-H...O, N-H...O and C-H...O hydrogen bonds, forming hydrophilic layers.

The effects of substitution on tetrakis(substituted imidazole)copper(II) trifluoromethanesulfonates.

The organic ligands 4-methyl-1H-imidazole and 2-ethyl-4-methyl-1H-imidazole react with Cu(CF(3)SO(3))(2).6H(2)O to give tetrakis(5-methyl-1H-imidazole-kappaN(3))copper(II) bis(trifluoromethanesulfonate), [Cu(C(4)H(6)N(2))(4)](CF(3)SO(3))(2), and aquatetrakis(2-ethyl-5-methyl-1H-imidazole-kappaN(3))copper(II) bis(tri fluoromethanesulfonate), [Cu(C(6)H(10)N(2))(4)(H(2)O)](CF(3)SO(3))(2). In the former, the Cu atom has an elongated octahedral coordination environment, with four imidazole rings in equatorial positions and two trifluoromethanesulfonate ions in axial positions. This conformation is similar to those in the analogous complexes tetrakis(imidazole)copper(II) trifluoromethanesulfonate and tetrakis(2-methyl-1H-imidazole)copper(II) trifluoromethanesulfonate. In the second of the title compounds, the ethyl groups block the central Cu atom, and a square-pyramidal coordination environment is formed around the Cu atom, with the substituted imidazole rings in the basal positions and a water molecule in the axial position.

Heterotrimetallic 4f-3d coordination polymers: synthesis, crystal structure, and magnetic properties.

A series of cyano-bridged heterotrimetallic complexes [CuL](2)Ln(H(2)O)(2)M(CN)(6).7H(2)O have been synthesized by the reactions of CuL (L(2)(-) = dianion of 1,4,8,11-tetraazacyclotradecane-2,3-dione), Ln(3+) (Ln = Gd or La), and [M(CN)(6)](3)(-) (M = Co, Fe, or Cr). X-ray diffraction analysis reveals that these complexes are isostructural and have a novel chain structure. The Ln(3+) ion is eight-coordinated by six oxygen atoms of two CuL and two water molecules and two nitrogen atoms of the bridging cyano ligands of two [M(CN)(6)](3)(-), while the [M(CN)(6)](3)(-) anion connects two Ln(3+) using two trans-CN(-) ligands giving rise to a chainlike structure. In the chain, every CuL group tilts toward the CN(-) ligand of adjacent [M(CN)(6)](3)(-) with the Cu-N(cyano) contacts ranging from 2.864(6) to 2.930(6) A. Magnetic studies on the CuGdCo complex (1) indicate the presence of ferromagnetic coupling between Cu(II) and Gd(III). The CuLaCr (5) and CuLaFe (2) complexes exhibit ferromagnetic interaction between paramagnetic Cu(II) and Cr(III)/Fe(III) ions through the weak cyano bridges (Cu-N(cyano) = 2.930(6) A for 2). A global ferromagnetic interaction is operative in the CuGdFe complex (3) with the concurrence of dominant ferromagnetic Cu(II)-Gd(III) and minor antiferromagnetic Gd(III)-Fe(III) as well as the ferromagnetic Cu(II)-Fe(III) interaction. For the CuGdCr complex (4), an overall antiferromagnetic behavior was observed, which is attributed to the presence of dominant antiferromagnetic Cr(III)-Gd(III) coupling and the minor ferromagnetic Cu(II)-Gd(III) and Cu(II)-Cr(III) interaction. Moreover, a spin frustration phenomenon was found in complex 4, which results from the ferro-ferro-antiferromagnetic exchanges in the trigonal Cu-Gd-Cr units. The magnetic susceptibilities of these complexes were simulated using suitable models. The magneto-structural correlation was investigated. These complexes did not show a magnetic phase transition down to 1.8 K.

Pendant macrocyclic metallic building blocks for the design of cyano-bridged heterometallic complexes with 1D chain and 2D layer structures.

A series of cyano-bridged Ni(II)-Cr(I/III) complexes have been synthesized by the reactions of hexaazacyclic Ni(II) complexes with [Cr(CN)(6)](3-) or [Cr(CN)(5)(NO)](3-). Using the tetravalent Ni(II) complex [Ni(H(2)L(2))](4+) (L(2) = 3,10-bis(2-aminoethyl)-1,3,6,8,10,12-hexaazacyclotetradecane), one-dimensional chainlike complexes were produced and subject to magnetic studies, affording the intermetallic magnetic exchange constants of J(1) = +0.23 cm(-1) and J(2) = +8.4 cm(-1) for the complex [Ni(H(2)L(2))][Cr(CN)(5)(NO)]ClO(4).5H(2)O (1) and of J = +5.9 cm(-1) for the complex [Ni(H(2)L(2))](4)[Cr(CN)(6)](5)OH.15H(2)O (2). X-ray diffraction analysis shows that complex 1 has a zigzag chain structure, whereas complex 2 consists of a branched chain structure. Complex 2 exhibits antiferromagnetic ordering at 8.0 K (T(N)). When an octahedral Ni(II) complex cis-[NiL(3)(en)](2+) (en = 1,2-ethylenediamine, L(3) = 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane) was used for the synthesis, the common 2D honeycomb-layered complex [NiL(3)](3)[Cr(CN)(5)(NO)](2).8H(2)O (3) was obtained, which has a T(N) value of 3.3 K. Below T(N), a metamagnetic behavior was observed in complexes 2 and 3.

From one-dimensional chain to pentanuclear molecule. Magnetism of cyano-bridged Fe(III)-Ni(II) complexes.

Two cyano-bridged Ni(II)-Fe(III) complexes [(H(3)O)[Ni(H(2)L)](2)[Fe(CN)(6)](2).[Fe(CN)(6)].6H(2)O](n) (1) and [K(18-C-6)(H(2)O)(2)][Ni(H(2)L)](2)[Fe(CN)(6)](3).4(18-C-6).20H(2)O (2) (L = 3,10-bis(2-aminoethyl)-1,3,6,8,10,12-hexaazacyclotetradecane, 18-C-6 = 18-crown-6-ether) have been synthesized and characterized structurally and magnetically. Complex 1 has a zigzag one-dimensional structure, in which two trans-CN(-) ligands of each [Fe(CN)(6)](3)(-) link two trans-[Ni(H(2)L)](4+) groups, and in turn, each trans-[Ni(H(2)L)](4+) links two [Fe(CN)(6)](3)(-) in a trans fashion. Complex 2 is composed of cyano-bridged pentanuclear molecules with moieties connected by the trans-CN(-) ligands of [Fe(CN)(6)](3)(-). Magnetic studies show the existence of ferromagnetic Ni(II)-Fe(III) interactions in both complexes. The intermetallic magnetic coupling constant of both complexes was analyzed by using an approximate model on the basis of the structural features.

Characterization of a soluble molecular magnet: unusual magnetic behavior of cyano-bridged Gd(III)-Cr(III) complexes with one-dimensional and nanoscaled square structures.

Two cyano-bridged Gd(III)-Cr(III) complexes [Gd(urea)(4)(H(2)O)(2)](2)[Cr(CN)(6)](2) (1) and ([Gd(capro)(2)(H(2)O)(4)Cr(CN)(6)].H(2)O)(n)(2) (capro represents caprolactam) have been synthesized and characterized structurally and magnetically. Complex 1 has a tetranuclear Gd(2)Cr(2) square structure, in which two cis-CN(-) ligands of each [Cr(CN)(6)] link two [Gd(urea)(4)(H(2)O)(2)] groups and in turn, two [Gd(urea)(4)(H(2)O)(2)] link two [Cr(CN)(6)] in a cis fashion. Complex 2 is composed of 1D chains with alternating [Gd(capro)(2)(H(2)O)(4)] and [Cr(CN)(6)] moieties connected by the trans-CN(-) ligands of [Cr(CN)(6)]. The dehydration of 2 at 120 degrees C generates a new complex, [Gd(capro)(2)(H(2)O)(2)Cr(CN)(6)] (2'). Magnetic studies show the existence of antiferromagnetic Gd(III)-Cr(III) interaction in these complexes. On the basis of the tetranuclear model, the magnetic susceptibilities of 1 have been analyzed giving the intermetallic magnetic coupling constant of -0.36 cm(-1). Complex 2' exhibits a ferrimagnetic order below 2.1 K. Interestingly, 2' is quite soluble in water, and slow evaporation of the solution gives the hydrated complex 2. Therefore, 2' is a soluble molecular magnet, and this significant behavior implies potential applications. Isothermal magnetization measurements of 2' and other cyano-bridged Gd(III)-Cr(III) molecular magnets show unusual field-induced metamagnetic behavior from the ferrimagnetic ground state to the ferromagnetic state. Field dependence of magnetization of the cyano-bridged Gd(III)-Cr(III) complexes shows unusual field-induced metamagnetic behavior from the ferrimagnetic ground state to the ferromagnetic state.