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A new 3-D mixed valence copper-azido coordination polymer, [Cu I · Cu II (N 3 )(pzc) 2 (H 2 O)] n 1 , has been synthesized and characterized, and its magnetic properties studied. In this compound, the azide acts as rare asymmetric μ 1,1,3 bridging mode. The azide ligands and the Cu(2) ions act as 3-connecting nodes, and the Cu(1) ions act as 4-connecting nodes. The overall net takes rare topology with the Schlafli symbol of (6.8 2 )(6.8 2 )(6.8 5 ).

A new azido-NiII complex constructed from nicotinate has been obtained by cation−anion pairs as templates under hydrothermal conditions, which exhibits three-dimensional Kagome topology and ferromagnetic coupling.

A new 3D Mn(II) coordination polymer, [Mn(2)(HCO(2))(L)(2)(N(3)) x MeOH](infinity) (1) (L = nicotinate N-oxide), was synthesized by a solvothermal reaction and characterized magnetically. Complex 1 is a typical antiferromagnet with alternating azide/azide/formate/formate bridges, exhibiting a new -J(1)J(1)J(2)J(2)- coupling sequence. This is the first complex to contain an azide, formate and another type of carboxylate ligand.

Two new 3D copper(II) azido isomers, [Cu(N3)(nic)]infinity (1 and 2) (nic = nicotinate), have been synthesized and characterized. To the best of our knowledge, 1 is the first metal azido complex showing rutile-type topology, while 2 is a chiral compound obtained by spontaneous resolution upon crystallization.

Two M(II) tetranuclear complexes bridged only by azido, Mn4(N3)(7.3)Cl(0.7)L4 (1) and Co4(N3)8L4 (2) in which the four M(II) ions are precisely coplanar bridged only by six azido anions, were obtained by using 4,5-diazafluoren-9-one (L) as a corner ligand. Magnetic studies indicate that ferromagnetic coupling was conducted by the azido anions between M(II) ions. At low temperature, 1 exhibits a large magnetocaloric effect and 2 shows field-induced multiple magnetic relaxations.

A magnetic isolated chain-based substituted cobalt-formate framework was obtained with isonicotine as a spacer. In the chain, canted antiferromagnetic interactions exist in between the Co(II) ions, and slow magnetic relaxation is detected at low temperature. For the block effects of the isonicotine ligands, the complex could be considered as a peculiar example of a weak ferromagnetic single-chain-magnet.

We describe a new application of megaprimer polymerase chain reaction (PCR) for constructing a tandemly repeated DNA sequence using the drought responsive element (DRE) from Arabidopsis thaliana as an example. The key feature in the procedure was PCR primers with partial complementarity but differing melting temperatures (T(m)). The reverse primer had a higher T(m), a 3' end complementary to the DRE sequence and a 5' region complementary to the forward primer. The initial cycles of the PCR were conducted at a lower primer annealing temperature to generate products that served as megaprimers in the later cycles conducted at a higher temperature to prevent annealing of the forward primer. The region of overlap between the megaprimers was extended for generating products with a variable copy number (one to four copies) of tandem DRE sequence repeats (71 bp). The PCR product with four tandem repeats (4× DRE) was used as a template to generate tandem repeats with higher copies (copy number large than four) or demonstrated to bind DRE-binding protein in an yeast one-hybrid assay using promotorless reporter genes (HIS and lacZ). This PCR protocol has numerous applications for generating DNA fragments of repeated sequences.

Five new isomorphic three-dimensional (3D) heterometallic 3d-3d azide complexes, [CuNi(1-x)Co(x)(N(3))(2)(isonic)(2)](∞) (x = 0 for 1, x = 0.3 for 2, x = 0.5 for 3, x = 0.6 for 4, and x = 1 for 5), were obtained by assembling Cu(II), M(II) (Ni(II) and Co(II)), azide, and pyridyl carboxylate in hydrothermal condition. The 3D structure can be described as end on (EO) azide and syn,syn carboxylates mixed bridged alternate Cu-M chains linked by the pyridyl groups. Dominant ferromagnetic interactions were observed between the Cu(II) and M(II) ions in the chains. At low temperature diverse magnetic phenomena were presented in those complexes. As the Ni(II) ions were replaced by Co(II) ions with large anisotropy, the magnetism of the complexes change gradually from metamagnet to single-chain magnet (SCM)-like behaviors.

Two new azido-Co(II) complexes with pyrazine carboxylato ligands, [Co(N(3))(L)·H(2)O](n) (L = pyrazine-2-carboxylato) (1) and [CoNa(N(3))(2)(L)](n) (2), have been obtained by carefully tuning the Co(II):N(3)(-) ratio. Here we present the structural and magnetic characterization of these new species. Modulation of the coordination environment of Co(II) leads to a variation of the magnetic properties of the obtained compounds. Complex 1 exhibits ferromagnetically coupled [Co(2)] units that form the rungs of the ladder with a nearly negligible coupling between these units, while complex 2 is a 2D arrangement of 1D Co(II) single-chain magnets.

By changing template cation but introducing trivalent iron ions in the known niccolite structural metal formate frameworks, three complexes formulated [NH(2)(CH(3))(2)][Fe(III)M(II)(HCOO)(6)] (M = Fe for 1, Mn for 2, and Co for 3) were synthesized and magnetically characterized. The variation in the compositions of the complexes leads to three different complexes: mixed-valent complex 1, heterometallic but with the same spin state complex 2, and heterometallic heterospin complex 3. The magnetic behaviors are closely related to the divalent metal ions used. Complex 1 exhibits negative magnetization assigned as Neel N-Type ferrimagnet, with an asymmetric magnetization reversal in the hysteresis loop, and complex 2 is an antiferromagnet with small spin canting (α(canting) ≈ 0.06° and T(canting) = 35 K), while complex 3 is a ferrimagnet with T(N) = 32 K.

The hydrothermal reaction of Ni(NO(3))(2).6H(2)O, NaN(3) phenanthroline and nicotinic acid yielded a one-dimensional (1D) complex, [Ni(1.5)(N(3))(2)(phen)(nic)](n) (1) (phen = phenanthroline, nic = nicotinate), which is a new example of the named orbital countercomplementarity-like complex. In 1, the nicotinate shows mu(3)-nic-N,O,O coordination mode, and the azide groups adopt mu(1,1) bridging mode linking Ni(II) ions to form a rare trinuclear Ni(II) unit bridged by a double mu(1,1) azido.

A new three-dimensional Mn(II) complex, [Mn(3)(HCO(2))(2)(L)(2)(OCH(3))(2)], 1 (L = nicotinate N-oxide), was synthesized by solvothermal reaction and magnetically characterized. Complex 1 exhibits an unprecedented 3,6-connected 5-nodal net topology with Schlafli notation {4(2);6}4{4(3)}2{4(6);6(6);8(3);10}2{4(8);6(6);8} and was assigned as a homospin ferrimagnet. Interestingly, when 1 was placed in air for ca. one month, the methoxy anions in 1 were gradually exchanged by hydroxyl anions and 1 underwent a single-crystal-to-single-crystal structural transition to a new but similar complex, [Mn(3)(HCO(2))(2)(L)(2)(OH)(2)] x 4 H(2)O, 2. The anion exchange and water molecules filling the channels of 2 affect the magnetic behavior at low temperature compared to that of 1.

Through the use of a series of structurally related benzoates bearing different substituents as coligands, three new azido-copper compounds, [Cu(benzoate)(N(3))](n) (1), [Cu(2-methyl-benzoate)(N(3))](n) (2), and [Cu(1-naphthoate)(N(3))](n) (3), have been successfully obtained and structurally and magnetically characterized. Single-crystal structure analyses indicated that the uncoordinating substituents in the benzoates greatly affect the structure of the complexes. Complex 1 displays isolated ferromagnetic chains with the largest Cu-N-Cu angle in known carboxylate/end-on-azido mixed-bridged copper systems, while complexes 2 and 3 were 2D coordination polymers, containing mu-(1,1,3,3) and mu-(1,1,3) bridging azides and exhibiting new azido-copper networks with (4(4)) and (4.8(2)) topologies, respectively. Furthermore, 2 was a chiral complex obtained through spontaneous resolution. In the low-temperature range, both 2 and 3 showed spontaneous magnetization with characteristics of soft ferromagnetic magnetism with phase transition temperatures of 13 and 10 K, respectively.

The investigation of magnetic materials with fascinating structures and unusual magnetic behavior has witnessed flourishing development. Transition-metal hydroxides are of particular significance because of their potential application in magnetic devices (as substitutes for traditional ferrite or nanometric magnetic memory units), and have been extensively explored. Even so, it is still a tremendous challenge for researchers to rationally design, precisely control, artfully modulate, and effectively re-assemble new transition-metal/hydroxide species (hydroxide-bridged clusters, chains, and layers). In the hydroxyl inorganic layers (such as Cu(OH)2, FeO(OH), Mg(OH)2, etc.), the hydroxide groups are present in m2 and m3 modes. To replace some of the hydroxide ligands with other bridging groups in order to alter the magnetic properties is still a challenge to chemists today. As we know, azide is one of the most studied ligands in magnetochemistry, and its complexes display exciting magnetic properties ranging from long-range ordering to SMM (single-molecule magnet) and SCM (single-chain magnet) behavior. Additionally, the magnetic interaction through an azide bridge can be easily predicted based on its bridging mode and the M-N-M angles. The most typical bridging modes are end-to-end (EE, m2-1,3) and end-on (EO, m2-1,1), usually resulting in antiferromagnetic and ferromagnetic coupling, respectively, but this greatly depends on the Cu-N-Cu angle for end-on azides. Azides can also bridge more than two ions in their EO mode; for instance, it can bridge three metal ions in a pyramidal fashion analogous to that of a m3-OH group. In view of azides being able to take both m2-1,1 and m3-1,1,1 bridging modes, it may replace some OH positions in the 2D inorganic layer, which could lead to different magnetic behavior. To avoid the inorganic layer collapsing or aggregating into a 3D solid, a second ligand is usually introduced into the system. Herein, phthalic acid (H2-pta) is our second ligand of choice. A Cu / N3 /OH /pta network could have a high negative charge and counterion will then be needed. Herein we report the synthesis of an unusual 2D N3-Cu -OH complex, [CuACHTUNGTRENNUNG(H2O)6]ACHTUNGTRENNUNG[{Cu2(N3)4/3-(OH) ACHTUNGTRENNUNG(pta)}6] (1). Indeed, our results show that the [Cu ACHTUNGTRENNUNG(H2O)6] 2+ complex ion from the CuACHTUNGTRENNUNG(NO3)2 aqueous solution may serve as a template for the [Cu24] macrocycles. The crystal structure of complex 1 (Figure 1) consists of a new anionic 2D layer network containing two Cu ions, one phthalic anion (in m4-O,O’,O’’,O’’’ bridging mode), one m3 hydroxyl anion, and =3 azide anions, which take m2-1,1 and m3-1,1,1 bridging modes (Figure S1). As can be seen in Figure 1 (top), Cu1 is five-coordinate with a distorted square-based pyramid CuN2O3 geometry formed by the coordination of two nitrogen atoms, from the m2-1,1and m31,1,1-azide anions (apical position) (Cu1 N1=2.000(5), Cu1 N4=2.287(3) ;), and three oxygen atoms, one from the m3 hydroxyl anion and two from phthalic anions (Cu1 O5=1.969(4), Cu1 O1=1.983(4), Cu1 O4=2.018(4) ;). The square-based pyramidal coordination sphere of Cu2 is CuNO4, in which the N atom is from a m2-1,1 azide anion (Cu2 N1A=1.972(5) ;), and the four oxygen atoms are from two m3 hydroxyl anions and two phthalic anions (one occupied the apical position) (Cu2 O5=1.954(4), Cu2 O5A=1.979(4), Cu2 O2=2.646, Cu2 O3=1.934(4) ;). Two hydroxyl anions in the m3 mode (Cu1-O5-Cu2=100.74, Cu1-O5-Cu2A=118.24, Cu2-O5-Cu2A=100.308) bridge [a] Y.-F. Zeng, X. Hu, J.-P. Zhao, B.-W. Hu, Dr. F.-C. Liu, Prof. X.-H. Bu Department of Chemistry Nankai University Tianjin 300071 (China) Fax: (+86)22-2350-2458 E-mail : buxh@nankai.edu.cn [b] Dr. E. C. SaCudo Departament de QuJmica InorgKnica Universitat de Barcelona Diagonal, 647, Barcelona (Spain) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/chem.200800068.

A novel one-dimensional manganese(II) azido complex, [Mn2(N3)4(phen)2]n (1), in which the azido bridging ligands take on an unusual new type of combination with the metal center as the sign of [−EO−EO−EO−EE−]n, has been hydrothermally synthesized, and its magnetic properties have been studied.

The molecular 1:1 complexation of cinchona alkaloids by mono(6-deoxy-6-{[(R)-1-(hydroxymethyl)propyl]amino})-beta-cyclodextrin (1) in aqueous solution has been investigated by 2D-NMR, fluorescence titration, and fluorescence-lifetime experiments. Generally, with 1 as the host, in contrast to beta-cyclodextrin proper, strong binding of quinine (2; Ka = 84,200 M(-1)) and quinidine (3; Ka = 27,300 M(-1)) at pH 6.8 was observed, as monitored by an increase in fluorescence intensity, with a fair degree of diastereoisomer discrimination (ca. 3:1). To rationalize these results, two possible cooperative complexation modes, including specific H-bonding interactions to the chiral tether of the cyclodextrin portion, are proposed.

A new chiral 3D heterometallic coordination polymer [NaCo2(L)2(N3)·(MeOH)]∞ (1) (L = 2,6-pyridinedicarboxylate) was synthesized and characterized magnetically. Ferro- and antiferromagnetic interactions co-exist in 1, which results in a magnetic phase transition at the high temperature of 29 K.

The Cu(II) ions usually have different coordinated geometry to other 3d ions, especially Ni(II) and Co(II) ions, in azido-carboxylate mixed ligand systems. That provides a potential way to synthesize rare heterometallic 3d-3d azido complexes with peculiar magnetic properties. Assembling Cu(II), M(II) (M = Ni and Co), azido and nicotinic acid in hydrothermal condition, two novel isomorphic 3D heterometallic 3d-3d azido complexes, [CuM(N(3))(2)(nicotinate)(2)](∞) (M = Ni(II) for 1 and Co(II) for 2) were obtained. The structure of the complexes can be described as EO azido and syn,syn carboxylate mixed bridged spin sequence chains (-1/2-J(1)-1-J(2)-1/2- for 1 and -1/2-J(1)-3/2-J(2)-1/2- for 2) linked by the pyridyl groups. Dominant ferromagnetic interactions were observed between the Cu(II) and M(II) ions in the chains despite the largest M-N-M angle of about 129° in the 3d metal azido-carboxylate mixed coordinated systems and weak antiferromagnetic interactions between the chains. At low temperature, a spin-flop phase transition was present in the Co(II) involved complex 2.

Three new 1D lanthanide-azido complexes, [Ln(2)(N(3))(isonic)(2)-(OH)(3)(Hisonic)(H(2)O)](n) (Ln = Gd(III), Eu(III) and Sm(III)), were synthesized by hydrothermal reaction and their magnetic properties were studied.

A new 3D porous Ni(II)-azido complex has been synthesized and characterized and exhibits guest sorption properties explored by single-crystal to single-crystal transformations and linear ferromagnetic chains held together by a Ni-isonicotinate framework.

Four novel AgI coordination complexes with azole heterocycle ligands bearing acetic acid group, [AgL1]n (1), [Ag(L2HL2)]n (2), [AgL3]n (3) and [Ag(L4)]n (4) (here, HL1 = 1H-imidazole-1-acetic acid, HL2 =1H-benzimidazole-1-acetic acid, HL3 =1H-1,2,4-triazole-1-acetic acid, HL4 =1H-benzotriazole-1-acetic acid), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Structural analyses show that complex 1 possesses a two-dimensional structure, which contains silver chains formed by weak Ag–Ag interactions, and 2 consists of neutral chains connected by weak bonds (O⋯H⋯O), while 3 and 4 have a three-dimensional network and a one-dimensional chain structure, respectively. It is interesting that in 1 there exist Ag–Ag interactions with a separation of 3.156 A, which play an important role in the formation of the complex. Furthermore, the conductivity of 1 was studied in the powder state.

The reaction of LnIII salts with 1,5-naphthalenedisulfonate (1,5-NDS) or 2,7-naphthalenedisulfonate (2,7-NDS), and phenanthroline (phen) under hydrothermal conditions gave a series of new 2-D complexes {[Ln(1,5-NDS)1.5(phen)2(H2O)2]·3H2O}n [Ln = EuIII (1), GdIII (2), NdIII (3), TbIII (4)] and dinuclear compounds [Ln2(2,7-NDS)2(μ2-OH)2(phen)4(H2O)2]·4H2O [Ln = EuIII (5), GdIII (6), TbIII (7)], respectively. 1–4 are puckered (6,3) networks with 1,5-NDS as a bridge and phen chelating to LnIII ions. 5–7 are hydroxyl bridged dinuclear entities, which extend to 2-D networks by H-bonds.