Synthesis and structural characterization of bi- and trimetallic octacyanometalate(IV) complexes: [Delta,Lambda-MII(en)3][cis-MII(en)2(OH2)][MIV(CN)8].2H2O and [cis-MII(en)2(OH2)]2[(mu-NC)2MIV(CN)6].4H2O (MII = Mn, Co, Ni; MIV = Mo, W)

Treatment of [M(II)(en)(3)][OTs](2) or methanolic ethylenediamine solutions containing transition metal p-toluenesulfonates (M(II) = Mn, Co) with aqueous K(4)M(IV)(CN)(8).2H(2)O or Cs(3)M(V)(CN)(8) (M(IV) = Mo, W; M(V) = Mo) affords crystalline clusters of [M(II)(en)(3)][cis-M(II)(en)(2)(OH(2))(mu-NC)M(IV)(CN)(7)].2H(2)O (M(IV) = Mo; M(II) = Mn, 1; Ni, 5; M(IV) = W; M(II) = Mn, 2; Ni, 6) and [cis-M(II)(en)(2)(OH(2))](2)[(mu-NC)(2)M(IV)(CN)(6)].4H(2)O (M(IV) = Mo; M(II) = Co, 3; Ni, 7; M(IV) = W; M(II) = Co, 4) stoichiometry. Each cluster contains cis-M(II)(en)(2)(OH(2))(mu-NC)(2+) units that likely result from dissociative loss of en from [M(II)(en)(3)](2+), affording cis-M(II)(en)(2)(OH(2))(2)(2+) intermediates that are trapped by M(IV)(CN)(8)(4-).     

RbCrIII(C2O4)2·2H2O,Cs2Mg(C2O4)2·4H2O and Rb2CuII(C2O4)2·2H2O: three new complex oxalate hydrates

Rubidium chromium(III) dioxalate dihydrate [di­aqua­bis(μ‐oxalato)­chromium(III)­rubidium(I)], [RbCr(C₂O₄)₂(H₂O)₂], (I), and dicaesium magnesium dioxalate tetrahydrate [tetra­aqua­bis(μ‐oxalato)­magnesium(II)­dicaesium(I)], [Cs₂Mg(C₂­O₄)₂(H₂O)₄], (II), have layered structures which are new among double‐metal oxalates. In (I), the Rb and Cr atoms lie on sites with imposed 2/m symmetry and the unique water molecule lies on a mirror plane; in (II), the Mg atom lies on a twofold axis. The two non‐equivalent Cr and Mg atoms both show octahedral coordination, with a mean Cr—O distance of 1.966 Å and a mean Mg—O distance of 2.066 Å. Dirubid­ium copper(II) dioxalate dihydrate [di­aqua­bis(μ‐oxalato)­copper(II)­dirubidium(I)], [Rb₂Cu(C₂O₄)₂(H₂O)₂], (III), is also layered and is isotypic with the previously described K₂‐ and (NH₄)₂Cu^II(C₂O₄)₂·2H₂O compounds. The two non‐equivalent Cu atoms lie on inversion centres and are both (4+2)‐coordinated. Hydro­gen bonds are medium‐strong to weak in the three compounds. The oxalate groups are slightly non‐planar only in the Cs–Mg compound, (II), and are more distinctly non‐planar in the K–Cu compound, (III).     

Some Cyclization Reactions with 1,3-Diphenyl-5-Imino-2-Imidazolidinone-4-Thione

1,3-Diphenyl-5-imino-2-imidazolidinone-4-thione (II) was treated with diazomethanes to give (III-V). Interaction of (II) with amino compounds furnished the corresponding 4-substituted imino derivatives (VIa-m). Imidazoquinoxaline derivatives (VIIIb, c) were obtained through interaction of (II) with o-phenylenediamines. Condensation of (II) with hydrazines afforded the hydrazones (IX, Xa, b). Semicarbazone and thiosemicarbazone derivatives (XIIa-d) were prepared from the reaction of (IX) with isocyanates and isothiocyanates. Again (II) was allowed to react with n-butylmagnesium bromide and HgCl₂ to give (XIII) and (XIV) respectively.     

A Ferromagnetic Interaction between Cu(2+) Centers through a [CrO(4)](2-) Bridge: Crystal Structures and Magnetic Properties of [{Cu(acpa)}(2)(&mgr;-MO(4))] (M = Cr, Mo) (Hacpa = N-(1-Acetyl-2-propyridene)(2-pyridylmethyl)amine)

The reaction of [Cu(acpa)](+) with [MO(4)](2)(-) (Hacpa = N-(1-acetyl-2-propyridene)(2-pyridylmethyl)amine and M = Cr and Mo) in water-methanol or water-acetonitrile solution affords dinuclear copper(II) complexes with metalate bridges, [{Cu(acpa)}(2)(&mgr;-CrO(4))].4CH(3)OH.4H(2)O (1) and [{Cu(acpa)}(2)(&mgr;-MoO(4))].4H(2)O (2), respectively. The crystal structures and the magnetic properties have been studied. Complexes 1 and 2 are isomorphous and the structures are made up of discrete dimers in which two copper(II) ions are bridged by the [MO(4)](2)(-) anion. The coordination geometry about the copper(II) ions is square planar with a N(2)O chelate group from acpa and an oxygen atom from [MO(4)](2)(-). Magnetic susceptibility measurements for 1 revealed that a ferromagnetic interaction between copper(II) ions is propagated through the [CrO(4)](2)(-) bridge and the coupling constant (2J) was evaluated to be 14.6(1) cm(-)(1) (H = -2JS(1).S(2)). In 2, two copper(II) ions bridged by [MoO(4)](2)(-) anion are antiferromagnetically coupled with the 2J value of -5.1(4) cm(-)(1). The ferromagnetic interaction in 1 is explained by means of the orbital topology of frontier orbitals. Crystal data: 1, monoclinic, space group P2(1)/m, a = 8.349(2) ?, b = 17.616(3) ?, c = 10.473 ?, beta = 107.40(2) degrees, Z= 2; 2, monoclinic, space group P2(1)/m, a = 8.486(2) ?, b = 18.043(3) ?, c = 9.753(2) ?, beta = 95.82(2) degrees, Z = 2.     

SYNTHESIS OF 3-(2-MERCAPTO-4-THIAZOLYL)-2H-1-BENZOPYRAN-2-ONE AND ITS DERIVATIVES

Abstract

Treatment of 3-(2-bromoacetyl)coumarins with ammonium dithiocarbamate provides 3-2-mercapto-4-thiazolyl)-2H-1-benzopyran-2-one (11) but not 4-hydroxy-4-(3-coumaririnyl) thiazolidine-2-thione (I). II undergoes smooth condensation with alkyl, aralkyl, phenacyl and acid halides to give corresponding thioethers and thioesters (III) respectively. The structures of the newly synthesized compounds were established on the basis of spectral data (IR, PMR and MS).     

由己二酸根桥联的新颖双U形四核铜配合物: [Cu4(phen)4(NO3)2(H2O)2(adip)4/4(Hadip)4/2](NO3)2•2H2O

邻菲罗啉、己二酸和硝酸铜在水溶液中反应得到一种新颖的四核铜配合物[Cu4(phen)4(NO3)2(H2O)2- (adip)4/4(Hadip)4/2](NO3)2•2H2O (其中H2adip＝己二酸), 并经元素分析, IR, UV, TG和X射线单晶衍射分析表征. 该配合物晶体属三斜晶系, 空间群, a＝1.0146(2) nm, b＝1.0261(2) nm, c＝1.8285(4) nm, α＝91.66(3)°, β＝92.19(3)°, γ＝112.76(3)°, V＝1.7520(6) nm3, Z＝1, Dc＝1.639 g/cm3, C66H66Cu4N12O28, Mr＝1729.47, F(000)＝886, μ＝1.294 mm－1, R1和wR2分别为0.0447和0.1141. 己二酸根通过4个羧基O将两个U形双核亚单元联接成具有一个对称中心的双U形四核结构, 其中每个U型亚单元包含晶体学上不对称的2个Cu(II)原子. 每个Cu(II)离子均处于畸变的四方锥配位环境, 除与己二酸氢根(Hadip)、己二酸根(adip)和邻菲罗啉(Phen)的N, O配位形成锥底平面外, 其中的1个Cu(II)与水配位, 而另一个Cu(II)则与硝酸根配位. 配合物晶体结构中存在着广泛的氢键和p×××p作用.     

Macrocyclic nickel(II) complexes coligated by hydrosulfide and hexasulfide ions: syntheses, structures, and magnetic properties of [NiII2L(mu-SH)]+ and [(LNiII2)2(mu-S6)]2+

The borohydride complex [Ni(II)2L(mu-BH4)]+ (3) where L(2-) represents a sterically demanding hexaaza-dithiophenolate ligand reacts rapidly with elemental sulfur in acetonitrile at ambient temperature to produce the cationic complexes [Ni(II)2L(mu-SH)]+ (4) and [(Ni(II)2L) 2(mu-S6)]2+ (6). Both complexes were isolated as ClO4(-) or BPh4(-) salts and characterized by IR and UV/vis spectroscopy and X-ray crystallography. Complex 4 (also accessible from [Ni(II)2L(ClO4)]+ (5) and Na2S.9H2O) features an unprecedented N3Ni(II)(mu-SR)2(mu-SH)Ni(II)N3 core structure, the hydrosulfide ligand being deeply buried in the binding-cavity of the bowl-shaped [Ni(II)2L]2+ complex. In 6, a helical S6(2-) chain, with a structure reminiscent to that of plastic sulfur, is almost completely encapsulated by two [Ni(II)2L]2+ subunits. In contrast to other triply sulfur-bridged N3Ni(II)(SR)3Ni(II)N3 structures whose ground states are typically of S = 0, 4 reveals an S = 2 ground-state which is attained by a ferromagnetic exchange interaction between the two Ni(II) (S = 1) ions ( J = 18 cm (-1), H = -2JS1S2). Intradimer ferromagnetic exchange interactions are also present in 6 ( J = 23 cm (-1)). A qualitative explanation for this difference is offered.     

Relative stabilities of metal complexes of 4-(2-pyridylazo)resorcinol and 4-(2-thiazolylazo)resorcinol

The stability constants of 1:1 complexes of 4-(2-pyridylazo)resorcinol (PAR) and 4-(2-thiazolylazo)resorcinol (TAR) with Mn(II), Ni(II), Cu(II) and Zn(II) have been determined spectrophotometrically at μ = 0.1 and 25°C. The method is based on indirect estimation of the protonated and normal complexes by measuring the ligand absorption peak. Both protonated and normal complexes of these metals with PAR are more stable than those with TAR. The reverse order was previously observed for the pronated complexes of the lanthanides(III). The different behaviour of the 3d transition metals(II) compared to the lanthanides(III) is discussed. The proton dissociation constants of the protonated complexes of PAR or TAR with various metals are also discussed.     

Synthesis and crystal structure of ionic multicomponent complex: ([Cr(I)(PhH)(2)].+))(2)[Co(II)TPP(C(60)(CN)(2))]-[C(60)(CN)(2)](.-).3(o-C(6)H(4)Cl(2)) containing C(60)(CN)(2).- radical anion and sigma-bonded diamagnetic Co(II)TPP(C(60)(CN)(2)) -anion

The ionic multicomponent complex complex: ([Cr(I)(PhH)(2)].+))(2)[Co(II)TPP(C(60)(CN)(2))]-[C(60)(CN)(2)](.-).3(o-C(6)H(4)Cl(2)) (Co(II)TPP: cobalt (II) tetraphenylporphyrin; Cr(PhH)(2): bis(benzene)chromium; o-C(6)H(4)Cl(2): o-dichlorobenzene) containing CoTPP(C(60)(CN)(2)- anion and C(60)(CN)(2).- radical anion was obtained. The complex has the cage structure with channels, which accommodate Cr(I)(PhH)(2)(.+) and o-C(6)H(4)Cl(2) molecules. For the first time the sigma-bonding of Co(II)TPP to the fullerene radical anion with the essentially shortened Co.C(C(60)(CN)(2)) contact of 2.282 A is observed. The sigma-bonding results in the diamagnetism of Co(II)TPP(C(60)(CN)(2))(-) anion. The nonbonded C(60)(CN)(2)(.-) radical anion retains both the C(2)(v)symmetry and the shape of the molecule. The length of the C(triple bond)N bonds is 1.141 and 1.152 A.     

Two new [Ni(tren)2]2+ complexes: [Ni(tren)2]Cl2 and [Ni(tren)2]WS4

Both title compounds, bis­[tris(2‐amino­ethyl)­amine]­nickel(II) dichloride, [Ni(tren)₂]Cl₂, (I), and bis­[tris(2‐amino­ethyl)­amine]­nickel(II) tetra­thio­tungstate, [Ni(tren)₂]WS₄, (II), contain the [Ni(tren)₂]²⁺ cation [tren is tris(2‐amino­ethyl)­amine, C₆H₁₈N₄]. The tren mol­ecule acts as a tridentate ligand around the central Ni atom, with the remaining primary amine group not bound to the central atom. In (I), Ni²⁺ is located on a centre of inversion surrounded by one crystallographically independent tren mol­ecule. In the [Ni(tren)₂]²⁺ cation of (II), the Ni atom is bound to two crystallographically independent tren mol­ecules. The Ni atoms in the [Ni(tren)₂]²⁺ complexes are in a distorted octahedral environment consisting of six N atoms from the chelating tren mol­ecules. The counter‐ions are chloride anions in (I) and the tetrahedral [WS₄]^2? anion in (II). Hydro­gen bonding is observed in both compounds.     

Coordination algorithms control molecular architecture: [CuI4(L2)4]4+ grid complex versus [MII2(L2)2X4]y+ side-by-side complexes (M=Mn,Co, Ni,Zn; X=solvent or anion) and [FeII(L2)3][Cl3FeIIIOFeIIICl3

The synthesis and characterisation of a pyridazine-containing two-armed grid ligand L2 (prepared from one equivalent of 3,6-diformylpyridazine and two equivalents of p-anisidine) and the resulting transition metal (Zn, Cu, Ni, Co, Fe, Mn) complexes (1-9) are reported. Single-crystal X-ray structure determinations revealed that the copper(I) complex had self-assembled as a [2 x 2] grid, [Cu(I) (4)(L2)(4)][PF(6)](4).(CH(3)CN)(H(2)O)(CH(3)CH(2)OCH(2)CH(3))(0.25) (2.(CH(3)CN)(H(2)O)(CH(3)CH(2)OCH(2)CH(3))(0.25)), whereas the [Zn(2)(L2)(2)(CH(3)CN)(2)(H(2)O)(2)][ClO(4)](4).CH(3)CN (1.CH(3)CN), [Ni(II) (2)(L2)(2)(CH(3)CN)(4)][BF(4)](4).(CH(3)CH(2)OCH(2)CH(3))(0.25) (5 a.(CH(3)CH(2)OCH(2)CH(3))(0.25)) and [Co(II) (2)(L2)(2)(H(2)O)(2)(CH(3)CN)(2)][ClO(4)](4).(H(2)O)(CH(3)CN)(0.5) (6 a.(H(2)O)(CH(3)CN)(0.5)) complexes adopt a side-by-side architecture; iron(II) forms a monometallic cation binding three L2 ligands, [Fe(II)(L2)(3)][Fe(III)Cl(3)OCl(3)Fe(III)].CH(3)CN (7.CH(3)CN). A more soluble salt of the cation of 7, the diamagnetic complex [Fe(II)(L2)(3)][BF(4)](2).2 H(2)O (8), was prepared, as well as two derivatives of 2, [Cu(I) (2)(L2)(2)(NCS)(2)].H(2)O (3) and [Cu(I) (2)(L2)(NCS)(2)] (4). The manganese complex, [Mn(II) (2)(L2)(2)Cl(4)].3 H(2)O (9), was not structurally characterised, but is proposed to adopt a side-by-side architecture. Variable temperature magnetic susceptibility studies yielded small negative J values for the side-by-side complexes: J=-21.6 cm(-1) and g=2.17 for S=1 dinickel(II) complex [Ni(II) (2)(L2)(2)(H(2)O)(4)][BF(4)](4) (5 b) (fraction monomer 0.02); J=-7.6 cm(-1) and g=2.44 for S= 3/2 dicobalt(II) complex [Co(II) (2)(L2)(2)(H(2)O)(4)][ClO(4)](4) (6 b) (fraction monomer 0.02); J=-3.2 cm(-1) and g=1.95 for S= 5/2 dimanganese(II) complex 9 (fraction monomer 0.02). The double salt, mixed valent iron complex 7.H(2)O gave J=-75 cm(-1) and g=1.81 for the S= 5/2 diiron(III) anion (fraction monomer=0.025). These parameters are lower than normal for Fe(III)OFe(III) species because of fitting of superimposed monomer and dimer susceptibilities arising from trace impurities. The iron(II) centre in 7.H(2)O is low spin and hence diamagnetic, a fact confirmed by the preparation and characterisation of the simple diamagnetic iron(II) complex 8. M?ssbauer measurements at 77 K confirmed that there are two iron sites in 7.H(2)O, a low-spin iron(II) site and a high-spin diiron(III) site. A full electrochemical investigation was undertaken for complexes 1, 2, 5 b, 6 b and 8 and this showed that multiple redox processes are a feature of all of them.     

Thermal and kinetic studies on solid complexes of 2-(2-benzimidazolylazo)-4-acetamidophenol with some transition metals

The preparation and characterization of 2-(2-benzimidazolylazo)-4-acetamidophenol (BIAAP) complexes are reported. Different physico-chemical methods like IR, Magnetic, solid reflectance spectra and molar conductance, were used to investigate the structure of BIAAP complexes. In particular, the thermal decomposition of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of BIAAP is studied in nitrogen atmosphere. All the complexes do not contain coordinated water molecules but contain (2-4) water molecules of crystallization. The water molecules were removed in a single step. The complexes of Co(II) and Ni(II) ions exhibited a phase transition and the decomposition or combustion of BIAAP occurred in the second and subsequent steps. The final decomposition products were identified by mass spectrometry as the corresponding metal oxides or carbonate. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes were evaluated and the stabilities of the thermal decomposition of the complexes are discussed. From the kinetic point of view, it is found that the thermal stability of the complexes follows the order Ni(II) > Cu(II) > Zn(II) > Fe(III) > Co(II) > Cd(II).     

Reversible cation/anion extraction from K2La2Ti3O10: formation of new layered titanates, KLa2Ti3O9.5 and La2Ti3O9

A new soft-chemical transformation of layered perovskite oxides is described wherein K2O is sequentially extracted from the Ruddlesden-Popper (R-P) phase, K2La2Ti3O10 (I), yielding novel anion-deficient KLa2Ti3O(9.5) (II) and La2Ti3O9 (III). The transformation occurs in topochemical reactions of the R-P phase I with PPh4Br and PBu4Br (Ph = phenyl; Bu = n-butyl). The mechanism involves the elimination of KBr accompanied by decomposition of PR4+ (R = phenyl or n-butyl) that extracts oxygen from the titanate. Analysis of the organic products of decomposition reveals formation of Ph3PO, Ph3P, and Ph-Ph for R = phenyl, and Bu3PO, Bu3P along with butane, butene, and octane for R = butyl. The inorganic oxides II and III crystallize in tetragonal structures (II: P4/mmm, a = 3.8335(1) A, c = 14.334(1) A; III: I4/mmm, a = 3.8565(2) A, c = 24.645(2) A) that are related to the parent R-P phase. II is isotypic with the Dion-Jacobson phase, RbSr2Nb3O10, while III is a unique layered oxide consisting of charge-neutral La2Ti3O9 anion-deficient perovskite sheets stacked one over the other without interlayer cations. Interestingly, both II and III convert back to the parent R-P phase in a reaction with KNO3. While transformations of the R-P phases to other related layered/three-dimensional perovskite oxides in ion-exchange/metathesis/dehydration/reduction reactions are known, the simultaneous and reversible extraction of both cations and anions in the conversions K2La2Ti3O10 right harpoon over left harpoon KLa2Ti3O9.5 right harpoon over left harpoon La2Ti3O9 is reported here for the first time.     

Ultraviolet spectra of 2-phenyl-4- and 2-phenyl-5-azaindan-1, 3-diones

The UV spectra of 2-phenyl-4-azaindan-1, 3-dione (I), 2-phenyl-5-azaindan-1, 3-dione (II), and their N-methylbetaines are investigated. 2×10^–5 M aqueous alcoholic solutions of 2-phenyl-4-azaindan-1, 3-dione (I) contain the anionic form (IA), and in solutions of 2-phenyl-5-azaindan-1, 3-dione (II) the betaine form (IIB) is also in equilibrium with the anion (IIA). Solutions of I and II in 0.1 M sulfuric acid are characterized by a wide and rather intense absorption band at about 500 m, indicating the presence of a betaine form (IB and IIB). In 2M hydrochloric acid solution 2-phenylazaindan-1, 3-diones and their N-methylbetaines (III and IV) are protonated at the oxygen atom, giving the enol forms of the N-protonated or corresponding N-methylated 2-phenylazaindandiones.     

Stepwise synthesis of [Ru(trpy)(L)(X)](n+) (trpy = 2,2':6',2' '-terpyridine; L = 2,2'-dipyridylamine; X = Cl-, H2O, NO2-, NO+, O2-). Crystal structure, spectral, electron-transfer, and photophysical aspects

Ruthenium-terpyridine complexes incorporating a 2,2'-dipyridylamine ancillary ligand [Ru(II)(trpy)(L)(X)](ClO(4))(n) [trpy = 2,2':6',2' '-terpyridine; L = 2,2'-dipyridylamine; and X = Cl(-), n = 1 (1); X = H(2)O, n = 2 (2); X = NO(2)(-), n = 1 (3); X = NO(+), n = 3 (4)] were synthesized in a stepwise manner starting from Ru(III)(trpy)(Cl)(3). The single-crystal X-ray structures of all of the four members (1-4) were determined. The Ru(III)/Ru(II) couple of 1 and 3 appeared at 0.64 and 0.88 V versus the saturated calomel electrode in acetonitrile. The aqua complex 2 exhibited a metal-based couple at 0.48 V in water, and the potential increased linearly with the decrease in pH. The electron-proton content of the redox process over the pH range of 6.8-1.0 was calculated to be a 2e(-)/1H(+) process. However, the chemical oxidation of 2 by an aq Ce(IV) solution in 1 N H(2)SO(4) led to the direct formation of corresponding oxo species [Ru(IV)(trpy)(L)(O)](2+) via the concerted 2e(-)/2H(+) oxidation process. The two successive reductions of the coordinated nitrosyl function of 4 appeared at +0.34 and -0.34 V corresponding to Ru(II)-NO(+) --> Ru(II)-NO* and Ru(II)-NO* --> Ru(II)-NO(-), respectively. The one-electron-reduced Ru(II)-NO* species exhibited a free-radical electron paramagnetic resonance signal at g = 1.990 with nitrogen hyperfine structures at 77 K. The NO stretching frequency of 4 (1945 cm(-1)) was shifted to 1830 cm(-1) in the case of [Ru(II)(trpy)(L)(NO*)](2+). In aqueous solution, the nitrosyl complex 4 slowly transformed to the nitro derivative 3 with the pseudo-first-order rate constant of k(298)/s(-1) = 1.7 x 10(-4). The chloro complex 1 exhibited a dual luminescence at 650 and 715 nm with excited-state lifetimes of 6 and 1 micros, respectively.     

Chloro- und Polyselenoselenate(II) Darstellung,Struktur und Eigenschaften von [Ph3(C2H4OH)P]2[SeCl4] · MeCN, [Ph4P]2[Se2Cl6] und [Ph4P]2[Se(Se5)2]

Chloro- and Polyselenoselenates(II): Synthesis, Structure, and Properties of [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN, [Ph₄P]₂[Se₂Cl₆], and [Ph₄P]₂[Se(Se₅)₂] By symproportionation of elemental selenium and SeCl₄ in polar protic solvents the novel chloroselenates(+II), [SeCl₄]^2? and [Se₂Cl₆]^2?, could be stabilized; they were crystallized with voluminous organic cations. They were characterized from complete X-ray structure analysis. Yellow-orange [Ph₃(C₂H₄OH)P]₂[SeCl₄] · MeCN (space group P1 , a = 10.535(4), b = 12.204(5), c = 16.845(6) Å, α = 77.09(3)°, β = 76.40(3)°, γ = 82.75(3)° at 140 K) contains in its crystal structure monomeric [SeCl₄]^2? anions with square-planar coordination of Se(+II). The mean Se? Cl bond length is 2.441 Å. In yellow [Ph₄P]₂[Se₂Cl₆] (space group P1 , a = 10.269(3), b = 10.836(4), c = 10.872(3) Å, α = 80.26(3)°, β = 79.84(2)°, γ = 72.21(3)° at 140 K) a dinuclear centrosymmetric [Se₂Cl₆]^2? anion, also with square-planar coordinated Se(+II), is observed. The average terminal and bridging Se? Cl bond distances are 2.273 and 2.680 Å, respectively. From redox reactions of elemental Se with boranate/thiolate in ethanol/DMF the bis(pentaselenido)selenate(+II) anion [Se(Se₅)₂]^2? was prepared as a novel type of a mixed-valent chalcogenide. In dark-red-brown [Ph₄P]₂[Se(Se₅)₂] (space group P2₁/n, a = 12.748(4), b = 14.659(5), c = 14.036(5) Å, β = 108.53(3)° at 140 K) centrosymmetric molecular [Se(Se₅)₂]^2? anions with square-planar coordination of the central Se(+II) by two bidentate pentaselenide ligands is observed (mean Se? Se bond lengths: 2.658 Å at Se(+II), 2.322 Å in [Se₅]_2?). The resulting six-membered chelate rings with chair conformation are spirocyclically linked through the central Se(+II). The vibrational spectra of the new anions are reported.     

Cover Picture: Coordination Algorithms Control Molecular Architecture: [CuI4(L2)4]4+ Grid Complex Versus [MII2(L2)2X4]y+ Side‐By‐Side Complexes (M=Mn,Co, Ni,Zn; X=Solvent or Anion) and [FeII(L2)3][Cl3FeIIIOFeIIICl3] (Chem. Eur. J. 16/2003)

The cover picture shows how differing coordination algorithms control the molecular architecture of complexes of the pyridazine‐containing, two‐armed, acyclic Schiff base ligand L2 (left, prepared from one equivalent of 3,6‐diformylpyridazine and two equivalents of d‐anisidine). Two very different complexes of L2 self‐assemble from tetrahedral copper(I ) versus octahedral zinc(II ), nickel(II ), and cobalt(II ) controlled 1 : 1 reactions with L2. In both cases the metal ions are bridged by the pyridazine moieties in L2, but in the case of the tetrahedral copper(II ) the result is a tetrametallic [2×2] grid complex ([Cu^I₄(L2)⁴]⁴⁺: top right), whilst in the case of the octahedral metal(II ) ions dimetallic side‐by‐side complexes, [M^II₂(L2)²(X)₄]^y+ (M = Mn, Co, Ni, Zn; X = solvent or anion), are formed (bottom right). The cover image was kindly generated by M. Crawford (University of Otago) with Strata Studio Pro (Strata). More details are given by S. Brooker and co‐workers on p. 3772 ff.     

Synthese von 1, 2-annelierten 1, 4-Benzodiazepinen und 4, 1-Benzoxazepinen

The syntheses of 1, 2-annelated 1, 4-benzodiazepines (IV, Y = N) and 4, 1-benzoxazepines (IV, Y = 0) are described (Scheme 1). The key step is a nucleophilic aromatic substitution of 2-substituted piperazines (II, Z = N? CH₃), piperidines (II, Z = CH₂) or pyrrolidines (II, Z= (CH₂)₀) with activated aryl halides (I).     

PHTHALOCYANINE AND NAPHTHALOCYANINE PHOTOSENSITIZED OXIDATION OF 2'-DEOXYGUANOSINE

Abstract— The photodynamic properties of the di-and tetrasulfonated zinc and aluminium phthalocyanines and a tetrasulfonated aluminium napththalocyanine were studied using 2'-deoxyguanosine as a DNA model compound. The major photooxidation products of this nucleoside were identified and classified according to their formation through a radical mechanism (type I) or a singlet oxygen mediated mechanism (type II). The major type I product was obtained and identified as 2,2-diamino [(2-deoxy-β- d - erythro pentofuranosyl)-4-amino]-5( 2H )-oxazolone. Two major type II products were characterized as the 4R* and 4S* diastereomers of 9-(2-deoxy-β- d - erythro pentofuranosyl)-7,8-dihydro-4-hydroxy-8-oxoguanine. In addition a third product, also resulting from a type II photooxidation, was identified as 8-oxo-7,8-dihydro-2'-deoxyguanosine. Quantification of these products provided a means to estimate the contribution of type I and type II pathways during the phthalocyanine and naphthalocyanine mediated photooxidation of 2'-deoxyguanosine, confirming the major role of singlet oxygen in these processes.     

Synthesis and properties of [Ru(2)(acac)(4)(bptz)](n+) (n=0,1) and crystal structure of [Ru(2)(acac)(4)(bptz)

The neutral complex [Ru(2)(acac)(4)(bptz)] (I) has been prepared by the reaction of Ru(acac)(2)(CH(3)CN)(2) with bptz (bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine) in acetone. The diruthenium(II,II) complex (I) is green and exhibits an intense metal-ligand charge-transfer band at 700 nm. Complex I is diamagnetic and has been characterized by NMR, optical spectroscopy, IR, and single-crystal X-ray diffraction. Crystal structure data for I are as follows: triclinic, P1, a = 11.709(2) A, b = 13.487(3) A, c = 15.151(3) A, alpha = 65.701(14) degrees, beta = 70.610(14) degrees, gamma = 75.50(2) degrees, V = 2038.8(6) A(3), Z = 2, R = 0.0610, for 4397 reflections with F(o) > 4sigmaF(o). Complex I shows reversible Ru(2)(II,II)-Ru(2)(II,III) and Ru(2)(II,III)-Ru(2)(III,III) couples at 0.17 and 0.97 V, respectively; the 800 mV separation indicates considerable stabilization of the mixed-valence species (K(com) > 10(13)). The diruthenium(II,III) complex, [Ru(2)(acac)(4)(bptz)](PF(6)) (II) is prepared quantitatively by one-electron oxidation of I with cerium(IV) ammonium nitrate in methanol followed by precipitation with NH(4)PF(6). Complex II is blue and shows an intense MLCT band at 575 nm and a weak band at 1220 nm in CHCl(3), which is assigned as the intervalence CT band. The mixed valence complex is paramagnetic, and an isotropic EPR signal at g = 2.17 is observed at 77 and 4 K. The solvent independence and narrowness of the 1200 nm band show that complex II is a Robin and Day class III mixed-valence complex.