The C–HCl2Cu(II) synthon in the structural direction and assembly of supramolecular complexes with the 3,3′-bis(2-benzimidazolyl)-2,2′-dipyridine ligand and its N-substituted derivatives

Three new Cu(II) supramolecular complexes [Cu(L₁)Cl₂]·2DMF (1), [Cu(L₂)Cl₂] (2) and [Cu(L₃)Cl₂]·DMF (3) (L₁ = 3,3′-bis(2-benzimidazolyl)-2,2′-dipyridine, L₂ = 3,3′- bis(N-ethyl-2-benzimidazolyl)-2,2′-dipyridine and L₃ = 3,3′-bis(N-benzyl-2-benzimidazolyl)-2,2′-dipyridine) have been prepared and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. X-ray structural analysis of L₁, L₂·3.5H₂O and L₃·H₂O indicates that all three ligands adopt the trans conformation with the two benzimidazole fragments located on opposite sides of the dipyridyl backbone. While in complexes 1–3, all the ligands display the cis conformation and behave as bidentate chelating reagents to coordinate with Cu(II). The inorganic chloride ions always act as a reliable hydrogen bonded acceptor in these structures, and the resulting C–HCl₂Cu supramolecular synthons play a significant role in the formation and stabilization of the structures. Moreover, additional non-covalent interactions, such as C–Hπ, are also identified to extend the discrete (0-D) or low-dimensional (1-D) motifs into high-dimensional architectures.     

Syntheses, Structure Characterizations and Fluorescent Properties of Two Reduced Molybdenum (V) Phosphates Functionalized by Zinc Coordination Complexes

Two new materials built from reduced molybdenum (V) phosphates as building blocks and zinc coordination complexes as linkers, (H₃O)₂[Zn(2,2′-bpy)]₄[Zn(H₂O)]₂[Zn(HPO₄)₂ (PO₄)₆(MoO₂)₁₂(OH)₆] · 6H₂O (2,2′-bpy=2,2′-bpyridine) 1 and [Zn(phen)(H₂O)₂]₂[Zn(phen) (H₂O)]₂[Zn(H₂O)]₂[Zn(HPO₄)₄ (PO₄)₄(MoO₂)₁₂ (OH)₆] · 7H₂O (phen=1,10-phenanthroline) 2, have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. Compound 1 is a new 3-D structure which constructed from Zn[P₄Mo₆]₂ dimers bonded together with [Zn(2,2′-bpy)] coordination complexes and [Zn(H₂O)] fragments. In compound 2, the Zn[P₄Mo₆]₂ dimeric units are linked by [Zn(phen)(H₂O)] coordination complexes and [Zn(H₂O)] fragments to form a new 2-D framework. The fluorescent activities of compounds 1 and 2 were reported. The crystal data for the two compounds are the following: 1, triclinic, P−1, a=13.036(3) ?, b=13.765(3) ?, c=14.459(3) ?, , Z=1; 2, triclinic, P−1, a=12.708(3) ?, b=14.016(3) ?, c=14.646(3) ?, , Z=1.Dedicated to Professor Michael T. Pope on the occasion of his retirement.     

A convenient synthetic route from isatin N-Mannich bases to nitrogen-containing derivatives of isoindigo

Abstract  

The reaction of aminomethylisatins (isatin N-Mannich bases) with hexaethylphosphorous triamide leads to the formation of 1,1′-bis(dialkylaminomethyl)-3,3′-bis(indolin-3-ylidene)-2,2′-diones and 1,1′-bis(1,3-dioxo-1,3-dihydroisoindol-2-ylmethyl)-1H,1′H-[3,3′]bisindolylidene-2,2′-dione.     

Investigation on the thermal decomposition some heterodinuclear NiII-MII complexes prepared from ONNO type reduced Schiff base compounds ( M II=ZnII, CdII)

N,N′-bis(salicylidene)-1,3-propanediamine (LH₂), N,N′-bis(salicylidene)-2,2′-dimethyl-1,3-propanediamine (LDMH₂), N,N′-bis(salicylidene)-2-hydroxy-1,3-propanediamine (LOH₃), N,N′-bis(2-hydroxyacetophenylidene)-1,3-propanediamine (LACH₂) and N,N′-bis(2-hydroxyacetophenone)-2,2′-dimethyl-1,3-propanediamine (LACDMH₂) were synthesized and reduced to their phenol-amine form in alcoholic media using NaBH₄ (L^HH₂, LDM^HH₂, LOH^HH₂, LAC^HH₂ and LACDM^HH₂). Heterodinuclear complexes were synthesized using Ni(II), Zn(II) and Cd(II) salts, according to the template method in DMF media. The complex structures were analyzed using elemental analysis, IR spectroscopy, and thermogravimetry. Suitable crystals of only one complex were obtained and its structure determined using X-ray diffraction, NiLAC^H·CdBr₂·DMF₂, space group orthorhombic, Pbca, a=20.249, b=14.881, c=20.565 ? and Z=8. The heterodinuclear complexes were seen to be of [Ni·ligand·MX₂·DMF₂] structure (ligand=L^H2−, LDM^H2−, LOH^H2−, LAC^H2−, LACDM^H2−, M=Zn^II, Cd^II, X=Br⁻, I⁻). Thermogravimetric analysis showed irreversible bond breakage of the coordinatively bonded DMF molecules followed by decomposition at this temperature.     

A ladder-like 4d–4f complex constructed from edge-sharing rhombus and square of Mo2Yb2 based on [Mo(CN)8]4? and Yb3+ ions as building Blocks

A novel 4d-4f complex, {Cs[Yb(MeOH)₃(DMF)(H₂O)Mo(CN)₈] · H₂O} _n (1) (DMF = N,N′-dimethylformamide) has been synthesized and structurally characterized. The complex 1 is a one-dimensional (1D) infinite chain, which adopts a 1D ladder-like structure motif assembled from an edge-sharing rhombus and square of Mo₂Yb₂ based on the [Mo(CN)₈]⁴⁻ and Yb³⁺ as building blocks. The complex 1 crystallizes in triclinic, space group P1 with a = 9.841(2) b = 10.226(2) ?, c = 13.404(3) ?, α = 82.02(3)°, β = 86.86(3)°, γ = 65.10(3)°, V = 1211.7(4) ?³ and Z = 2.     

Benzenedicarboxylate-modulated zinc(II)-3,5-bis(3-pyridyl)-1H-1,2,4-triazole frameworks: syntheses, structures and luminescent properties

Abstract  

Based on the polydentate ligand 3,5-bis(3-pyridyl)-1H-1,2,4-triazole (3,3′-Hbpt), three coordination compounds [Zn(3,3′-Hbpt)(ip)]·2H₂O (1), [Zn(3,3′-Hbpt)(5-NO₂-ip)]·H₂O (2), and [Zn(3,3′-Hbpt)₂(H₂pm)(H₂O)₂]·2H₂O (3) have been hydrothermally constructed with H₂ip, 5-NO₂-H₂ip and H₄pm as auxiliary ligands (H₂ip = isophthalic acid, 5-NO₂-H₂ip = 5-NO₂-isophthalic acid, H₄pm = pyromellitic acid). Structural analysis reveals that Zn(II) ions serve as four-coordinated, five-coordinated, and six-coordinated connectors in 1–3, respectively, while 3,3′-Hbpt adopts μ-N_py and N_py coordination modes in two typical conformations in these target coordination compounds. Dependently the applied ligand, compounds 1–3 exhibit either 1D channel, cage or chain structures, respectively. In addition, the luminescence properties of 1–3 have been investigated in the solid state at room temperature.     

New π ligand N,N,N,N′,N′,N′-hexaallylethylenediaminium (L2+): Synthesis and crystal structures of LBr2 · 2H2O and its cuprocomplexes L[CuII(Br0.45Cl3.55)], L[Cu 4I (Br4.55Cl1.45)], and L[Cu 4I Br6]

The alkylation of ethylenediamine with allyl bromide in the presence of a fourfold (with respect to ethylenediamine) molar amount of NaHCO₃ in acetone with an ethanol admixture (15: 1) affords LBr₂ · 2H₂O (I), where L²⁺ is the N,N,N,N′,N′,N′-hexaallylethylenediaminium cation. Single crystals of complexes L[Cu^II(Br_0.45Cl_3.55)] (II), L[Cu₄^I(Br_4.55Cl_1.45)] (III), and L[Cu₄^IBr₆] (IV) are prepared by ac electrochemical synthesis from an ethanolic solution of LBr₂ · 2H₂O, CuCl₂ · 2H₂O (or CuBr₂) at copper wire electrodes. The crystal structures of compounds I–IV are determined by X-ray diffraction analysis. The crystals of complex I are monoclinic: space group P2₁/n, a = 8.544(3), b = 10.404(3), c = 13.350(4) ?, β = 97.29(3)°, V = 1177.2(6) ?³, Z = 2. The bromine anions in compound I are bonded to the L²⁺ cations and water molecules through hydrogen contacts (E)H…Br (E = O, C) of 2.57(3)–2.86(3) ?. The crystals of compounds II–IV are triclinic: space group P . For II: a = 8.762(4), b = 9.163(4), c = 16.500(6) ?, α = 95.62(4)°, β = 96.39(4)°, γ = 111.46(4)°, V = 1211.4(9) ?³, Z = 2; for III: a = 9.074(4), b = 9.435(4), c = 9.829(5) ?, α = 116.12(4)°, β = 104.14(4)°, γ = 100.22(4)°, V = 692.3(6) ?³, Z = 1; for IV isostructural III: a = 9.084(4), b = 9.404(4), c = 9.869(4) ?, α = 116.31(3)°, β = 104.00(3)°, γ = 100.37(3)°, V = 692.1(5) ?³, Z = 1. Unlike the isolated tetrahedral CuX₄²⁻ anion in structure II, an original chain anion (Cu₄X₆²⁻) _n is observed in the structures of π complexes III and IV. Original Russian Text ? M.M. Monchak, A.V. Pavlyuk, V.V. Kinzhibalo, M.G. Mys’kiv, 2009, published in Koordinatsionnaya Khimiya, 2009, Vol. 35, No. 6, pp. 414–419.     

Synthesis and photochromic properties of a new biindenylidenedione compound bearing hydroxylphenyl groups in crystal state

A new biindenylidenedione compound, named [trans-anti-3,3′-Di-p-hydroxyl phenyl-3,3′-dihydroxy-[2,2′-bi-1H-indene]-1,1′-dione] (2) was synthesized and characterized by means of ¹H-NMR, IR, MS and X-ray crystallographic diffraction techniques. The photochromic behavior was investigated by means of UV–Vis spectroscopy, and the results showed that the inclusion complex of 2 with guest solvent N,N-dimethylformamide (DMF) did not exhibit photochromism in crystal state. The structure–property relation was discussed briefly in context to the intermolecular interactions and the solvent-dependent effect on photochromism.     

Structure and thermal properties of [RhPy4Cl2]X complex salts (X = Cl?, ReO 4? , ClO 4? )

[RhPy₄Cl₂]Cl·4H₂O (I), [RhPy₄Cl₂]ReO₄ (II), [RhPy₄Cl₂]ClO₄ (III), and [RhPy₄Cl₂]ReO₄·2H₂O complex salts were synthesized. The crystal structure of compounds II (P4/ncc, a = 25.5655(3) ?, c = 14.3521(4) ?), III (P2₁/n, a = 13.5308(3) ?, b = 15.1044(5) ?, c = 23.3457(8) ?, β = 93.327°), and dyhydrate of II (Pbcm, a = 10.6199(9) ?, b = 10.4964(9) ?, c = 22.9834(16)?) was determined by X-ray diffraction analysis. The thermal transformations of the complexes were studied by differential thermal analysis. The substances were characterized by IR spectroscopy, XRPA, and element analysis Original Russian Text Copyright ? 2009 by D. B. Vasilchenko, I. A. Baidina, E. Yu. Filatov, and S. V. Korenev __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 349–356, March–April, 2009.     

Synthesis,crystal structures,and magnetic properties of three isomorphous helical coordination polymers

Three isomorphous coordination polymers of general formula {[M(H₂bna)·(DMF)₂·(H₂O)₂]·DMF}_n (M = Co for 1, Mn for 2, Ni for 3, respectively, where H₄bna = 2,2′-dihydroxy-[1,1′]-binaphthalene-3,3′-dicarboxylate) were synthesized under solvothermal conditions and characterized by FTIR, single crystal X-ray diffraction, thermogravimetric analysis, and X-ray power diffraction analysis. All three polymers crystallize in the same monoclinic space group P2₁/n. The complexes are assembled into 1D helical chains, and each adjacent helical chain of the same chirality is further connected to form a chiral layer by hydrogen bond interactions. The layers are packed in alternating left-(M) and right-handed (P) chirality arrays. Magnetic studies reveal the presence of antiferromagnetic coupling interactions in complexes 1 and 2.     

A series of coordination polymers constructed from flexible bis(benzimidazole)ether ligands and different carboxylates

Six new coordination polymers constructed from two structurally related ligands, 2,2′-bis(2-methylbenzimidazole) ether (L1) and 2,2′-bis(2-ethylbenzimidazole)ether (L2), have been synthesized. They are [Cu(L1)(bz)₂] (1), [Cu(L2)(bz)₂] (2), [Zn₂(L1)(m-bdc)₂] (3), [Cd₂(L2)(m-bdc)₂(H₂O)]₂·H₂O (4), [Zn(L1)(OH-bdc)-(H₂O)] (5) and [Zn₂(L₂)(btca)] (6), where Hbz = benzoic acid, m-H₂bdc = 1,3-benzenedicarboxylic acid, OH-H₂bdc = 5-hydroxyisophthalic acid, and H₄btca = 1,2,4,5-benzenetetracarboxylic acid. In 1 and 2, the bidentate N-donor ligands (L1 and L2) bridge neighboring metal centers to form 1D single chains. The bz anions are attached on both sides of the chains. In 3 and 4, the N-donor ligands (L1 and L2) in cis conformations bridge two metal centers to generate a [M₂(L1)]⁴⁺ unit (M = Zn(II) and Cd(II)). The adjacent [M₂(L1)]⁴⁺ units are further linked via the dicarboxylate anions to form 1D double chain structures. In 5, the Zn(II) cations are bridged by OH-m-bdc anions to form an infinite polymeric chain. The L1 ligands are attached on one side of the chain in a monodentate mode. In 6, two Zn(II) cations are bridged by two L2 ligands to form a [ZnL2]₂ ⁴⁺ ring, which is further linked by btca anions to generate a 2D layer. The luminescent properties of the ligands and 3–6 in the solid state at room temperature were also studied.     

Crystal structure of the complex Zn(2,2′-Bipy)(C2H5OCS2)2 with mono- and bidentate ethylxanthate ligands

While seeking molecular precursors for ZnS films obtained by gas phase chemical deposition [1, 2] we synthesized mixed-ligand compounds ZnL(ROCS₂)₂ [R = i-Pr. /-Bu; L = 2,2′-bipyridyl (2,2′-Bipy), 1,10-phenanthroline (Phen)] [3]. The volatile complex Zn(2,2′-Bipy)(i-PrOCS₂)₂ was used as a precursor to obtain electroluminescent ZnS:Mn films [4]. According to XRD data, the compound Zn(Phen)(i-BuOCS₂)₂ is monomeric. The c.n. of zinc is six. The Phen and 1-B11OCS₂ ions behave as cyclic bidentate ligands [3, 5]. It was assumed that other mixed-ligand complexes with Phen and 2,2′-Bipy have an analogous structure [3]. Here we report on the structure of the known mixed-ligand complex of zinc(II) ethylxanthate with 2,2′-bipyridyl [6, 7]. It was found that the behavior of alkylxanthate ligands in mixed-ligand complexes of zinc(II) is more complex. Translated from Zhumal Stmktumoi Khimii, Vol. 41, No. 1, pp. 196-201, January–February, 2000.     

Two new cyanide-bridged complexes, {[Cu(men)2][Ni(CN)4]}n and [Mn(bpy)2]4[Mo(CN)8]2·0.5MeOH·0.75H2O: Syntheses and crystal structures

Two novel cyano-bridged complexes, {[Cu(men)₂][Ni(CN)₄] _n (1) (men = N,N′-dimethyl-ethylenediamine) and [Mn(bpy)₂]₄[Mo(CN)₈]₂·0.5MeOH·0.75H₂O (2) (bpy = 2,2′-bipyridine) have been synthesized and structurally characterized by IR spectroscopy and X-ray crystallography. The complex 1 has onedimensional zigzag chain structure in which the Ni atom is coordinated by four cyanide groups, and the Cu atom is surrounded by four nitrogen atoms of the two men ligands in equatorial plane and two nitrogen atoms of the bridging cyanide in axial positions; the Cu centre is in a distorted octahedral environment. Owing to weak interactions, complex 1 is self-assembled into two-dimensional network via N-H...N hydrogen bonds. In 2, the basic structural unit is centrosymmetric and contains four Mn centers connected by two octacyanomolybdates via eight cyanide bridges. Each Mo atom is linked via four cyanide groups to four Mn, and the other four cyanide groups are terminal. From X-ray single crystal analysis (room temperature), 1 crystallizes in monoclinic space group P2₁/n with a = 6.7332(7) ?, b = 13.9248(15) ?, c = 9.0869(10) ?, β = 98.4030(10)°, V = 843.05(16) ?³, Z = 2; 2 crystallizes in monoclinic space group P2₁/n with a = 13.886(6) ?, b = 24.116(11) ?, c = 15.263(7) ?, β = 90.175(6)°, V = 5111(4) ?³, Z = 2. Original Russian Text Copyright ? 2009 by X. Chen, P. Yang, S.-L. Ma, S. Ren, M.-Y. Tang, Y. Yang, Z.-J. Guo, and L.-Z. Liu The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 518–521, May–June, 2009.     

Heterometallic clusters with the {MoNbI8} core: The synthesis and crystal structures of (Ph4P)2[Mo5NbI8Cl6] and (4-MePyH)5[Mo5NbI8Cl6]Cl2

Heterometallic chloride complexes [Mo₅NbI₈Cl₆] ⁿ⁻ (n = 2, 3) are synthesized. The crystal structures of their salts are determined: for (Ph₄P)₂[Mo₅NbI₈Cl₆] (I), triclinic crystal system, spacegroup P [`1]\bar 1, a = 10.9886(6), b = 11.4604(5), c = 13.4343(7) ?, α = 66.124(2), β = 86.892(2), γ = 86.490(2)°, Z = 1, V = 1543.35(13) ?³; and for (4-MePyH)₅[Mo₅NbI₈Cl₆]Cl₂ (II), monoclinic crystal system, space group C2/m, a = 16.4937(4), b = 14.7335(3), c = 11.6534(3) ?, β = 99.8750(10)°, Z = 2, V = 2789.94(11) ? The geometric parameters of compounds I and II and the conditions for the formation of the complexes with the charges −2 and −3 are discussed.     

Kinetics and mechanism of propene hydroformylation catalyzed by rhodium complexes with a diphosphite ligand

The kinetics of propene hydroformylation in the presence of the catalytic system Rh(acac)(CO)₂/nL (L = 2,2′-bis[(1,1′-diphenyl-2,2′-diyl)phosphito]-3,3′,5,5′-tetra-tert-butyl-1,1′-diphenyl, 0.5 < n < 20) in para-xylene at 90°C is reported. At n ≥ 2, the rate and regioselectivity of the process are independent of the L concentration. The reaction is of positive fractional order with respect to propene and hydrogen and of negative order with respect to CO. The molar ratio between the linear product and the branched product decreases with an increasing CO pressure and increases with an increasing H₂ pressure. The kinetic data are consistent with a process mechanism involving irreversible propene addition to the unsaturated hydride complex HRh(CO)L with the formation of the π-complex HRh(CO)L(C₃H₆). The insertion of coordinated propene into the H-Rh bond of this complex is reversible in the linear aldehyde formation route and is quasi-equilibrium in the branched isomer formation route. The conclusions as to the character of these reaction steps are corroborated by the compositions of the but-1-ene and but-2-ene hydro-formylation products.     

Formation of polymeric chain assemblies of transition metal complexes with a multidentate Schiff-base

The new multidentate Schiff-base (E)-6,6′-((1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-ylidene))bis(4-methyl-2-((E)(pyridine-2-ylmethylimino)methyl)phenol) H₂L and its polymeric binuclear metal complexes with Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) are reported. The reaction of 2,6-diformyl-4-methyl-phenol with ethylenediamine in mole ratios of 2:1 gave the precursor 3,3′-(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1ylidene))bis(methan-1-yl-1-ylidene)bis(2-hydroxy-5-methylbenzaldehyde) W. Condensation of the precursor with 2-(amino-methyl)pyridine in mole ratios of 1:2 gave the new N₆O₂ multidentate Schiff-base ligand H₂L. Upon complex formation, the ligand behaves as a dibasic octadentate species with the involvement of the nitrogen atoms of the pyridine groups in coordination for all complexes. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectroscopic methods. These studies revealed octahedral geometries for Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) complexes of general formulae [Cr₂^III(L)Cl₂]Cl₂, [Ni₂^II(L)(H₂O)₂]Cl₂ and [M₂(L)Cl₂] and five co-ordinate Zn(II) complex of general formula [Zn₂^II(L)]Cl₂.     

Kinetic and mechanistic studies of the interaction of 2-mercapto pyridine with dichloro[1-alkyl-2-(arylazo)imidazole]palladium(II) complexes

Nucleophilic substitution of Pd(RaaiR′)Cl₂ [(RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C₆H₄-N=N-C₃H₂NN-1-R′; where R = H(a)/ Me(b)/ Cl(c) and R′ = Et(1)/Bz(2)] with 2-Mercaptopyridine (2-SH-Py) in acetonitrile (MeCN) at 298 K, to form [Pd₂(2-S-Py)₄], has been studied spectrophotometrically under pseudo-first-order conditions and the analyses support the nucleophilic association path. The reaction follows the rate law, Rate = {k ₀ + k [2-SH-Py] ₀ ² }[Pd(RaaiR′)Cl₂]: first order in Pd(RaaiR′)Cl₂ and second order in 2-SH-Py. The rate of the reaction follows the order: Pd(RaaiEt)Cl₂ (1) < Pd(RaaiBz)Cl₂ (2) and Pd(MeaaiR′)Cl₂ (b) < Pd(HaaiR′)Cl₂ (a) < Pd(ClaaiR′)Cl₂ (c). External addition of Cl⁻ (LiCl) and HCl suppresses the rate (Rate ∝ 1/[Cl⁻]₀ & ∝1/[HCl]₀). The reactions have been studied at different temperatures (293–308 K) and activation parameters (Δ^‡ H° and Δ ^‡ S°) of the reactions were calculated from the Eyring plot and support the proposed mechanism.     

Structure and synthesis of nitrosoruthenium trans -diammines [Ru(NO)(NH3)2Cl3] and [Ru(NO)(NH3)2(H2O)Cl2]Cl·H2O

A DTA study of thermal decomposition of (NH₄)₂[Ru(NO)Cl₅] in helium atmosphere has been carried out, a synthetic procedure for preparation of the trans-diammine complex mer-[Ru(NO)(NH₃)₂Cl₃] (I) with yield ∼70% has been developed. On re-crystallization of I from aqueous solution a trans-aquanitroso complex [Ru(NO)(NH₃)₂Cl₂(H2O)]Cl·H₂O (II) has been isolated. The structures of the compounds have been determined by single crystal X-ray diffraction: space group Pbcn, a = 6.607(1) ? b = 11.255(2) ? c = 9.878(2) ? (I) and space group Ima2, a = 8.3032(3) ?, b = 8.0890(2) ?, c = 15.9192(5) ? II). Original Russian Text Copyright ? 2008 by M. A. Il’in, V. A. Emel’yanov, and I. A. Baidina __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 6, pp. 1128–1136, November–December, 2008.     

Chlorine oxidation of coordinated ethylenediamine in triamineplatinum(IV) complex [PtEnPyCl3]Cl. Molecular structure of [PtPy(NH2-CH2-C≡N)Cl4] and [PtPy(NCl-(CH2)2-NH2)Cl3] crystals

The reaction of chlorine with triamine [PtEnPyCl₃]Cl in aqueous solution yields an insoluble powdered product, which is a mixture of compounds. Extraction with acetonitrile isolates a number of complexes: a glassy polymeric product (I), which contains a C=O group, an amino group, and pyridine; [PtPy(NH₂CH₂CN)Cl₄] (II) as the major product (ethylenediamine converts to aminoacetonitrile as a result of oxidative dehydrogenation); and the aminochloro complex [PtPy(NClCH₂CH₂NH₂)Cl₃] (III) in a minor amount. The IR spectra of the products were studied. X-ray structure analysis was carried out for complexes II and III. Compound II: orthorhombic space group Pbcm, a = 10.925(2) ?, b = 11.413(2) ?, c = 9.979(2) ?, V = 1244.3(4) ?³, Z = 8, R _hk1 = 0.033. The aminoacetonitrile molecule is coordinated to the platinum atom via the amino nitrogen atom in the trans position to pyridine; C≡N 1.07(2) ?, angle C-C≡N 178(1)°. Compound III: space group P2₁/n, a = 7.3016(8) ?, b = 7.8879(9) ?, c = 22.336(2) ?, β = 96.107(2)°, V = 1279.1(2) ?³, Z = 4, R _hk1 = 0.0808, N-Cl = 1.77(2) ?. Original Russian Text ? I.B. Baranovskii, M.D. Surazhskaya, G.G. Aleksandrov, M.A. Golubnichaya, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 7, pp. 1136–1141.     

Synthesis and self-assembly of reactive H-shaped block copolymers

The H-shaped block copolymers (PTMSPMA)₂-PEG(PMPSTMSPMA)₂ with two compositions, (EG)₉₁-b-(TMSPMA)₉₂ and (EG)₄₅₅-b-(TMSPMA)₁₇₆ have been successfully synthesized by atom transfer radical polymerization (ATRP) of tri(methoxylsilyl)propyl methacrylate (TMSPMA) at room temperature in methanol. The initiation system applied was composed of 2,2-bis(methylene α-bromoisobutyrate)propionyl terminated poly(ethylene glycol) (Br₂PEGBr₂) with M _n = 4000 or 2000, CuBr and 2,2′-bipyridine. The macroinitiator, Br₂PEGBr₂, was prepared by the reaction of two hydroxyl groups terminated PEG with 2,2-bis(methylene α-bromoisobutyrate)propionyl chloride. The NMR spectroscopy and GPC measurements were used to characterize the structure and molecular weight and molecular weight distribution of the resultant copolymers. The H-shaped block copolymers Sam 1 and Sam 2 were self-assembled in DMF/water mixtures and then the trimethoxysilyl groups in PTMSPMA were cross-linked by condensation reaction in the presence of triethylamine. Stable large-compound vesicles with 10 nm diameter of cavities were formed for Sam 1 which contains a short PEG chain. However, the self-assembling of the Sam 2 in the selective solvents resulted in big vesicles aggregates. These two different morphologies of aggregates are attributed to their relative chain length of water soluble PEG. The vesicles formed from Sam1 with short PEG chains have big surface energy which will lead them to self-assemble further, forming large-compound vesicles. __________ Translated from Acta Polymerica Sinica, 2007, 10: 974–978 [译自: 高分子学报]