The facile and effective one-pot solvothermal syntheses of 3,5-disubstituted 1,2,4-triazole and its derivatives (substituted group = alkyl, aryl, and pyridyl) through cyclocondensations of organonitriles and hydrazine hydrate in the absence/presence of metal salts have been established. By control of the solvothermal conditions and/or the addition of counteranions, different intermediates and final products were derived from various organonitriles, in which an intermediate N,N′-bis(picolinamide)azine (Hbpa) has been successfully trapped in its neutral manganese-(II) complexes. A systematical study shows that, after the initial formation of 2-pyridylamidrazone from 2-cyanopyridine and hydrazine, two reaction paths are involved in the formation of 1,2,4-triazoles: via the formation of 3,6-bis(2-pyridyl)-1,2-dihydro-1,2,4,5-tetrazine and Hbpa as intermediates. The tetrazine and Hbpa paths are preferred in the absence and presence of metal ions, respectively. In the presence of metal ions, metal ion binding can stabilize the tautomers, enhance the nucleophilic reactivity of the imino C atom, and inhibit the tautomerization of H bpa, hence leading to the formation of 1,2,4-triazolates or H bpa in complexed forms. The in situ cyclocondensation reactions of 2-pyridylamidrazone and carboxylate into asymmetric 3,5-disubstituted 1,2,4-triazolates under solvothermal conditions have also been observed for the first time. Crystal structures of the crystalline metal complexes have been obtained, including dinuclear [Mn(DPt)Cl (HO)] (1) and [Mn(bpt) (SCN)(HO)] (3; Hbpt = 3,5-bis(2-pyridyl)-4H-1,2,4-triazole), tetranuclear [Mn(H bpa)(mpt)(N)] ·2HO (5; Hmpt = 3-methyl-5-(2-pyridyl)-1H-1,2,4-triazole), [Mn(Hbpa)(pt)(N )]·2CHOH (6; Hpt = 5-(2-pyridyl)-1H-1,2,4-triazole), and [Mn(Hbpa) (SCN)]· 2CHOH (7), as well as helical [Cu(bpt)] (2). Among them, 7 is the first example of a neutral tetranuclear [2 x 2] grid manganese(II) complex. Both 5 and 7 exhibit antiferromagnetic interactions. © 2007 American Chemical Society.

Cheng    Wei Zhang    叶保辉    Jianbin Lin    陈小明    

Inorganic Chemistry

2007

Several important solvothermal (including hydrothermal) in situ metal/ligand reactions and their mechanisms, including dehydrogenative carbon-carbon coupling, hydroxylation of aromatic rings, cycloaddition of organic nitriles with azide and ammonia, transformation of inorganic and organic sulfur, as well as the Cu to Cu reduction, are outlined in this Account. The current progress clearly demonstrates the important potential of such reactions in the crystal engineering of functional coordination compounds and one-pot synthesis of some unusual organic ligands that are inaccessible or not easily obtainable via conventional methods, thereby substantiating our expectation that a new bridge has been created between coordination chemistry and synthetic organic chemistry. © 2007 American Chemical Society.

陈小明     童明良   

Accounts of Chemical Research

2007

Three helical supramolecular stereoisomers of meso-2, Δ-2, and Δ-3 with the formula of cis-[Ni(f-rac-L)][Ni(CN)] were successfully constructed based on the [Ni(f-rac-L) and [Ni(CN) ] building blocks (L = 5,5,7,12,12,14-hexamethyl-1,4,8, 11-tetraazacyclotetradecane). In all three supramolecular stereoisomers, cis-[Ni(f-rac-L)] cations are alternately bridged by [Ni(CN) ] anions through two cis (in meso-2 and Δ-2) or trans (in Δ-3) cyano groups to form one-dimensional (1D) helical chains of cis-[Ni(f-rac-L)][Ni(CN)]. In meso-2, the right/left-handed chirality of the originally formed chain is transferred oppositely to adjacent chains through the interchain hydrogen-bonding interactions of hexameric water clusters, leading to the formation of meso-2 with a central symmetrical space group, P2/n, in which the 1D helical chains are packed in an alternating right- and left-handed chirality. In Δ-2 and Δ-3, the right/left-handed chirality of the original chain is transferred uniformly to adjacent chains through the zipper-like interchain hydrophobic interactions, resulting in the formation of Δ-2 and Δ-3 with chiral space groups of P222 and P321, respectively, in which all of the 1D helical chains are arranged in the same right/left-handed chirality. © 2007 American Chemical Society.

Long Jiang    Feng Xiao-Long    苏成勇    陈小明     Tongbu Lu   

Inorganic Chemistry

2007

A solvothermal reaction of CoO, CoSO, pyridine-3,5-dicarboxylic acid, and HO in an aqueous MeCN solution yielded a three-dimensional coordination framework [Co (OH)(pdc)]·HO (1) (pdc = pyridine-3,5-dicarboxylate). Compound 1 shows an unprecedented (3,9)-connected (4.6)(4.6.8) topology in which hydroxycentered mixed-valence Co(OH)(CO ) clusters act as nine-connected nodes of a tricapped trigonal prism, and pdc groups act as three-connected nodes of trigonal geometry. © 2007 American Chemical Society.

Xianming Zhang    Yanzhen Zheng    Li Cui-Rui    Weixiong Zhang    陈小明    

Crystal Growth and Design

2007

(Graph Presented) Extraordinary structure: An unprecedented Co supercluster in which three CoO cubes surround a central μ-nitrate ligand exhibits single-molecule magnet behavior. The picture shows the structure of the Co core and the temperature dependence of the in-phase (χ′, full symbols) and out-of-phase (χ″, open symbols) components of the magnetic susceptibility at various ac frequencies. © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

Minghua Zeng    Minxia Yao    Hong Liang    Weixiong Zhang    陈小明    

Angewandte Chemie - International Edition

2007

Two new mixed-valence manganese-carboxylate clusters, [Mn Mn(OCPh) (μ-O)(μ-O)(μ-OMe) (MeOH)(HO)]· 1.5PhCOH·MeOH·6HO (1, PhCOH = benzoic acid) and [MnMn(OCCh)(μ-O) (μ-O)(μ-OMe)(MeOH)(H O)]·0.5MeOH·2.5HO (2, ChCOH= cyclohexanecarboxylic acid) contain new disklike Mn cores. Both 1 and 2 can be synthesized by the conventional manganese redox reaction (MnO oxidizing Mn) in methanol solution. 2 can be also synthesized via the site-specific ligand substitution reaction from 1. 1 crystallizes in the triclinic space group P1, whereas 2 crystallizes in the trigonal space group P3. Magnetic study shows that both 1 and 2 have the same ground spin states S = 2. Compared to the silence of the out-of-phase ac susceptibility of 1, 2 shows clearly slow magnetic relaxation behavior above 1.8 K due to the dramatically enhanced axial magnetic anisotropy (D = -0.89 and -1.58 cm for 1 and 2, respectively, which was obtained by fitting the plots of M vs H/T with the program ANISOFIT 2.0). © 2007 American Chemical Society.

Yanzhen Zheng    Xue Wei    Weixiong Zhang    童明良    陈小明    

Inorganic Chemistry

2007

(Graph Presented) Star formation: Polymeric [Fe(μ -O)(μ-OAc)(HO)][Fe (μ-O)μ-OAc)]· 7HO is synthesized by linking triangular {Fe(μ -O)} clusters through anti-anti bridging acetate ligands (see picture; red and blue: Fe, orange: O). Spin frustration and long-range magnetic order coexist in this compound below 4.5 K (see graph). © 2007 Wiley-VCH Verlag GmbH & Co. KGaA.

Yanzhen Zheng    童明良    Xue Wei    Weixiong Zhang    陈小明     Grandjean Fernande    Long Gary J.   

Angewandte Chemie - International Edition

2007

A new microporous metal-organic framework (MOF) material [Ni (dpa)(pyz)(HO)] · 11HO (1) with BCT zeolite topology has been hydrothermally synthesized. The framework components undergo dynamic structural transformation in response to removal and rebinding of the suitable guest molecules. © 2007 American Chemical Society.

Sheng Hu    Jiepeng Zhang    Li Hao-Xiang    童明良    陈小明     Susuma Kitagawa   

Crystal Growth and Design

2007

Solvothermal treatment of copper(II) salts, ammonia, and 4-cyanopyridine was chosen for the study of supramolecular isomerism of the target binary copper(I) 3,5-di(4-pyridyl)-1,2,4-triazolate (4-pytz). A 2D coordination network of α-[Cu(4-pytz)] (1, P2In, a = 7.9633(5) Å,b = 10.3757(6) Å, c = 13.1054(8) Å, β = 105.673(1)°) was obtained at 120-160 °C using Cu(OH) or Cu(OH) CO as the copper(II) source, while a 3D network of β-[Cu(4-pytz)] (2, Cc, a = 9.4278(5) Å, b = 24.7779(14) Å, c = 10.6761(6) Å, β = 113.025(1)°) was obtained at 100 °C using Cu(OH) as copper(II) source. A solvated copper(I) 3,5-di(4-pyridyl)-1,2,4-triazolate [Cu(4-pytz)(NH)]-4HO (3, P2//c, a = 9.2065(8) Å, b = 25.574(2) Å, c = 6.8104(6) Å, β = 90.256(2)°) with 1D coordination structure has also been synthesized at 100 °C using the Cu(NO) ·3HO as copper(II) source. Novel hydrogen-bonded water-ammonia ribbons comprised of fused (HO) and (HO)(NH) pentagons were stabilized in the 1D channels of 3. Networks 1 and 2 show structure-related photoluminescence properties, while 3 is nonemissive under UV irritation. © 2006 American Chemical Society.

Jiepeng Zhang    Yanyong Lin    Huang Xiao-Chun    陈小明    

Crystal Growth and Design

2006

A two-dimensional compound [Co(μ-OH) (1,2-chdc)] (1,2-chdc = trans-1,2-cyclohexane-dicarboxylate) comprising triangular arrays of Co (μ-OH) affording a Kagomé-like lattice exhibits the coexistence of spin frustration and long-range magnetic ordering. © The Royal Society of Chemistry 2006.

Yanzhen Zheng    童明良    Wei Zhang    陈小明    

Chemical Communications

2006