Binary group 15 polyazides. structural characterization of [Bi(N3)4]-, [Bi(N3)5]2-, [bipy·Bi(N3)5]2-, [Bi(N3)6]3-, bipy·As(N3)3, bipy·Sb(N3)3, and [(bipy)2·Bi(N3)3]2 and on the lone pair activation of valence electrons

The binary group 15 polyazides As(N(3))(3), Sb(N(3))(3), and Bi(N(3))(3) were stabilized by either anion or donor-acceptor adduct formation. Crystal structures are reported for [Bi(N(3))(4)](-), [Bi(N(3))(5)](2-), [bipy·Bi(N(3))(5)](2-), [Bi(N(3))(6)](3-), bipy·As(N(3))(3), bipy·Sb(N(3))(3), and [(bipy)(2)·Bi(N(3))(3)](2). The lone valence electron pair on the central atom of these pnictogen(+III) compounds can be either sterically active or inactive. The [Bi(N(3))(5)](2-) anion possesses a sterically active lone pair and a monomeric pseudo-octahedral structure with a coordination number of 6, whereas its 2,2'-bipyridine adduct exhibits a pseudo-monocapped trigonal prismatic structure with CN 7 and a sterically inactive lone pair. Because of the high oxidizing power of Bi(+V), reactions aimed at Bi(N(3))(5) and [Bi(N(3))(6)](-) resulted in the reduction to bismuth(+III) compounds by [N(3)](-). The powder X-ray diffraction pattern of Bi(N(3))(3) was recorded at 298 K and is distinct from that calculated for Sb(N(3))(3) from its single-crystal data at 223 K. The [(bipy)(2)·Bi(N(3))(3)](2) adduct is dimeric and derived from two BiN(8) square antiprisms sharing an edge consisting of two μ(1,1)-bridging N(3) ligands and with bismuth having CN 8 and a sterically inactive lone pair. The novel bipy·As(N(3))(3) and bipy·Sb(N(3))(3) adducts are monomeric and isostructural and contain a sterically active lone pair on their central atom and a CN of 6. A systematic quantum chemical analysis of the structures of these polyazides suggests that the M06-2X density functional is well suited for the prediction of the steric activity of lone pairs in main-group chemistry. Furthermore, it was found that the solid-state structures can strongly differ from those of the free gas-phase species or those in solutions and that lone pairs that are sterically inactive in a chemical surrounding can become activated in the free isolated species.     

Chlorine reaction with platinum triamine [Pt(N,N-DimeTm)PyCl3]Cl (N,N-DimeTm = (CH3)2N(CH2)3NH2). Crystal structure of [Pt(N,N-DimeTm)Cl2], [Pt(N,N-DimeTm(Py)Cl3]Cl · H2O and [Pt{(CH3)2N(CH2)2C(O)NH}(Py)Cl3]

Treatment of platinum(II) diamine [Pt(N,N-DimeTm)Cl₂] (I) with pyridine gave tetramine [Pt(N,N-DimeTm)Py₂]Cl₂ (II); by oxidation with chlorine this was converted to Pt(IV) triamine, [Pt“(N,N-DimeTm(Py)Cl₃]Cl (III) with a six-membered chelate ring. According to X-ray diffraction data, the reaction of complex II with chlorine is accompanied by removal of the pyridine molecule from the trans-position to the NH₂ group of N,N-dimethyltrimethylenediamine. The reaction of complex III with chlorine at 20°C afforded a mixture of compounds (IV) and the complex [Pt“(CH₃)₂N(CH₂)₂C(O)NH”(Py)Cl₃] (V) with an amidate six-membered metal ring, dimethylpropioamide, which was also isolated upon refluxing a mixture of IV in an aqueous solution. The UV/Vis and IR spectra of the obtained complexes were studied, and X-ray diffraction analysis of I, III, and V was performed. The crystals of I are triclinic, space group P $ \bar 1 $ ; a = 7.6526(4) Å, b = 11.5571(6) Å, c = 12.4432(7) Å, α = 113.85(1)°, β = 96.54(2)°, γ = 106.78(2)°; Z = 4; R _hkl = 0.051. The crystals of III are monoclinic, space group C2/c; a = 36.715(2) Å, b = 7.8179(4) Å, c = 29.721(16) Å, β = 127.80(1)°; Z = 16; R _hkl = 0.036. The crystals of V are monoclinic, space group P2₁/n; a = 7.0398(6) Å, b = 27.458(2) Å, c = 7.687(6) Å, β = 106.270(1)°; Z = 4; R _hkl = 0.052.     

Influence of Lewis acids on the [4+2] cycloaddition of (2R,2′R)-N,N′-fumaroylbis[fenchane-8,2-sultam] to cyclopentadiene and cyclohexadiene

Compared to the analogous bornane-10,2-sultam derived dienophile (−)-1b, the reversed topology observed during the [4+2] cycloaddition of cyclopentadiene or cyclohexadiene to the (−)-1a–TiCl₄ chelate can be rationalised on the basis of IR studies of their complexes with different Lewis acids. According to X-ray analyses, the origin of this differentiation resides in the loss of masked C₂ symmetry, due to the pseudoequatorial ‘down’ orientation of the SO(1) bond in (−)-1a,c as compared to the pseudoequatorial ‘up’ direction adopted by the SO(2) bond in (−)-1b,d, associated with the steric influence of the apical Ti–Cl atoms. Dependent on the strength of the Lewis acid, the much higher constraint of the SO₂/CO syn-s-cis conformer diminishes the chelating properties of this type of fenchane-8,2-sultam derived dienophiles (−)-1a and 1c.     

cis-Bis[N1,N2-bis(trimethylsilyl)benz­amidinato-κ2N1,N2]chloro(4-tolyl­imido-κN)vanadium(V)

The title complex, [V(C₇H₇N)(C₁₃H₂₃N₂Si₂)₂Cl], consists of a V metal centre coordinated to five N atoms and a Cl⁻ ion in a pseudo-octahedral arrangement. The N atoms of the benzamidinate ligands form two four-membered chelate rings to V, with bite angles of 63.59 (8) and 64.36 (8)°, whilst the fifth N atom is from a p-tolyl­imido ligand [V—N—C 172.2 (2)°] located cis with respect to the Cl⁻ ion [Cl—V—N_imido 96.96 (8)°].     

[Bu4N]2[Fe2(μ-S2O3)2(NO)4]: Synthesis,Structure, Redox Properties,and EPR Study

The [n-Bu₄N]₂[Fe₂(-S₂O₃)₂(NO)₄] complex was studied using X-ray diffraction analysis, cyclic voltammetry, and EPR spectroscopy, and its crystal structure was determined. The redox properties of the [Fe₂(-S₂O₃)₂(NO)₄]^2–anion in CH₃CN and CH₂Cl₂solutions were studied. An addition of excess reducer (sodium thiosulfate) to the thiosulfate complex was shown to produce an EPR signal with g= 2.03 typical of the mononuclear iron dinitrosyl complexes. The mechanism for [Fe₂(-S₂O₃)₂(NO)₄]^2–reduction was suggested.     

Hydrothermal synthesis of a mixed-valence hexamolybdate cluster: crystal structure of [HN(CH2CH2)3N]2[HMoVMoVI5O19]·[N(CH2CH2)3N]

The hydrothermal reaction of MoO₃, V, Na₂WO₄· 2H₂O, [N(CH₂CH₂)₃N](1,4-diazabicyclo[2.2.2] octane), and H₂O at 160°C for 90h gave dark-brown crystals of [HN(CH₂CH₂)₃N]₂[HMo^VMo^VI ₅O¹⁹]·[N(CH₂CH₂)₃N], (1), in 40% yield. Complex (1) is the first one-electron reduced mixed-valence hexamolybdate to be crystallized and structurally characterized. The crystal structure of (1) consists of discrete [HMo^VMo^VI ₅O₁₉]^2– anions, [HN-(CH₂CH₂)₃N]⁺ cations, and neutral [N(CH₂CH₂)₃N] molecules of crystallization.     

CRYSTAL STRUCTURE OF [Et_4N]_2[Mo_2O_2(μ-S)_2(S_2)_2]

<正> [(C2H5)4N]2[Mo2o2S2(S2)2], Mr = 676. 74, monoclinic, P21/c, a = 13.510(2), b = 14.373(2), c=14. 777(3)(?), β = 97.53(2)°, V = 2844.7(9) (?)3, Z = 4, Dc= 1. 58g/cm3, μ(MoKα) = 13.0cm-1, F(000) = 1384, R =0. 033 for 1803 observed reflections. The structure contains discrete [Mo2O2S2(S2)2]2- anions and Et4N+ cations. The two oxygen atoms bonded to the Mo atoms are in cis-form with respect to the Mo2S2 bridging unit, with an average Mo- O distance of 1. 678 (?), The Mo…Mo distance is 2. 832(1)(?).     

[Et_4N]_2[Zn_2(OPh)_2Cl_4]的合成和晶体结构

ZnCl2, PhONa和Et4NCl稨2O在乙腈溶剂中反应合成了一种二核锌配合物[Et4N]2[Zn2(OPh)2Cl4]。X射线衍射结果表明,晶体属单斜晶系,C2/m空间群,晶胞参数 a = 14.1366(2), b=13.6985(5), c=9.3308(3)牛?107.851(2)o, V=1719.92(9)?,C28H50O2N2Zn2Cl4,Mr=721.24,Z=2,Dx=1.393g/cm3,μ(MoKα)=1.732mm—1,F(000)=756, R=0.0552, wR=0.1534, S=1.027。 配合物是由2个阳离子Et4N+和1个阴离子[Zn2(OPh)2Cl4]2—组成。阴离子[Zn2(OPh)2Cl4]2—包含着1个中心Zn2O2菱形平面。配合物中的2个锌原子通过2个苯酚中的氧原子桥连,每个锌原子还与2个氯原子配位形成变形四面体结构。     

Bis(Saccharinato)Nickel(II) Complexes with 2-Aminomethyl and -Ethylpyridines. Syntheses,Crystal Structures,Spectral and Thermal Analyses of trans-[Ni(sac-N)2(ampy-N,N′)2] and trans-[Ni(sac-O)2(aepy-N,N′)2]

The trans-bis(saccharinato)nickel(II) complexes with 2-aminomethylpyridine (ampy) and 2-aminoethylpyridine (aepy) have been prepared and characterized by elemental analyses, i.r., u.v.–vis., magnetic measurements and single crystal X-ray diffraction. Both structures consist of discrete molecules of the title complexes, in which the nickel(II) ion lies on an inversion centre and is octahedrally coordinated by two bidentate (N,N) ampy or aepy ligands and two anionic sac ligands, occupying trans positions. The most interesting feature of the complexes is the coordination of sac. In [Ni(sac)₂(ampy)₂], sac is N-bonded, whereas it is O-coordinated in [Ni(sac)₂(aepy)₂]. The i.r. spectra and thermal behaviour of both complexes are discussed in detail.     

N,N′-methylenedipyridinium Pt(II) and Pt(IV) hybrid salts: synthesis, crystal and molecular structures of [(C5H5N)2CH2] · [PtCl4] and [(C5H5N)2CH2] · [PtCl6]

The highly insoluble organic-inorganic hybrid ionic compounds N,N??-methylenedipyridinium tetrachloroplatinate(II) [(C₅H₅N)₂CH₂] · [PtCl₄] and N,N??-methylenedipyridinium hexachloroplatinate(IV) [(C₅H₅N)₂CH₂] · [PtCl₆] were obtained by the treatment of N,N??-methylenedipyridinium dichloride monohydrate [(C₅H₅N)₂CH₂]Cl₂ · H₂O with K₂[PtCl₄] or (NH₄)₂[PtCl₆], respectively, in an aqueous solution. Both complexes were isolated, purified, characterised by elemental analysis, and their molecular structures were confirmed by powder X-ray diffraction. The crystal structure of both compounds consists of separated discrete dications [(C₅H₅N)₂CH₂]²⁺ and anions [PtCl _n ]^2? (n = 4 or 6). As anticipated, the dications formed a butterfly shape consisting of two pyridine rings bound to the methylene group via their N atoms, while the Pt centre had a square planar geometry in [(C₅H₅N)₂CH₂] · [PtCl₄] and an octahedral coordination in [(C₅H₅N)₂CH₂] · [PtCl₆]. Interestingly, both crystal structures are stabilised by intermolecular C-H??Cl non-standard hydrogen bonds, ??-?? ring interactions between two pyridine rings of adjacent dications, and also by Cl-?? interactions.     

Diaqua[N,N-di(2-carboxyethyl)-o-anisidinato]copper(II) Dihydrate [Cu(o-Andp)(H2O)2] · 2H2O: Synthesis and Crystal Structure

Crystals of [Cu(o-Andp)(H₂O)₂] · 2H₂O (where o-Andp^2–is -anisidine-N,N-di-3-propionate) were synthesized and studied using X-ray diffraction analysis. The crystals are triclinic: a= 12.063(1) Å, b= 12.483(3) Å, c= 13.586(2) Å, = 91.29(1)°, = 111.67(1)°, = 104.00(1)°, V= 1830.5(5) ų, space group P , Z= 2, and R= 0.0528 for 5965 reflections with I2(I). The two crystallographically independent complexes are isostructural. The tetragonal–bipyramidal coordination of copper(III) involves three O atoms, the N atom of the tetradentate ligand o-Andp^2–, and two O atoms from water. The aminodipropionate group of the ligand (average Cu–O 1.939 Å and Cu–N 2.051 Å) and one of the coordinated water molecules (Cu–O(w) 1.991 Å) lie in the equatorial plane. The second water molecule (Cu–O(w) 2.32 Å) and the methoxy O atom of o-Andp^2–(Cu–O 2.37 Å) are in the apical positions of the bipyramid.     

Reactions of [WI2(CO)(NCMe)(η2-RC2R)2] (R = Me or Ph) with carbon monoxide to give either [WI2(CO)2(η2-MeC2Me)2] or [W(-I) I(CO) (η2-PhC2Ph)2]2. Crystal structure of [WI2(CO) 2( η2-MeC2Me)2]

The complexes [WI₂(CO)(NCMe)(η2)-RC₂R)₂] (R = Me and Ph) react in CH₂Cl₂ with an excess of carbon monoxide to give initially the acetonitrile substituted products [WI₂(CO)₂(η²-RC₂R) ₂]. For R= Me, the complex [WI₂(CO)₂(η²- MeC₂Me)₂] (1) was isolated and its structure determined by X-ray crystallography. However, for R = Ph, dimerisation occurs to give the iodide-bridged compound [W(μ-I)I(CO)(η²-PhC₂Ph)₂]₂ (2) with loss of carbon monoxide. These reactions are reversible as 1 and 2 react with acetonitrile to give [WI₂(CO)(NCMe)(η²-RC₂R)₂]. The ¹³C NMR spectra of I and 2 indicate that the two alkyne ligands donate a total of six electrons to the tungsten in these complexes.     

Investigating the role of the outer-coordination sphere in [Ni(P(Ph)2N(Ph‑R)2)2]2+ hydrogenase mimics

A series of dipeptide substituted nickel complexes with the general formula, [Ni(P(Ph)(2)N(NNA-amino acid/ester)(2))(2)](BF(4))(2), have been synthesized and characterized (P(2)N(2) = 1,5-diaza-3,7-diphosphacyclooctane, and the dipeptide consists of the non-natural amino acid, 3-(4-aminophenyl)propionic acid (NNA), coupled to amino acid/esters = glutamic acid, alanine, lysine, and aspartic acid). Each of these complexes is an active electrocatalyst for H(2) production. The effects of the outer-coordination sphere on the catalytic activity for the production of H(2) were investigated; specifically, the impact of sterics, the ability of the side chain or backbone to protonate and the pK(a) values of the amino acid side chains were studied by varying the amino acids in the dipeptide. The catalytic rates of the different dipeptide substituted nickel complexes varied by over an order of magnitude. The amino acid derivatives display the fastest rates, while esterification of the terminal carboxylic acids and side chains resulted in a decrease in the catalytic rate by 50-70%, implicating a significant role of protonated sites in the outer-coordination sphere on catalytic activity. For both the amino acid and ester derivatives, the complexes with the largest substituents display the fastest rates, indicating that catalytic activity is not hindered by steric bulk. These studies demonstrate the significant contribution that the outer-coordination sphere can have in tuning the catalytic activity of small molecule hydrogenase mimics.     

[2Fe2S]铁硫蛋白活性中心模型[Fe2S2(SR)4]2-(R=-H,-CH3)的局部自旋探讨

为了检验Davidson和Clark的局部自旋原理对铁硫蛋白簇合物的可行性,[Fe2S2(SR)4]2-(R=-H,-CH3)模型被选为研究对象.该目的可通过计算这些体系的局部自旋期望值〈SA.SB〉,〈S2A〉和mA,并讨论它们与Heisenberg自旋模型(HSM)和Noodleman对称破缺理论之间的联系来实现.在具体的计算中采用了自旋非限制Hartree-Fock(UHF)和自旋极化密度泛函(Spin-polarized DFT)方法,同时比较它们的计算质量.此外,采用多种方案计算了它们的交换耦合常数,并同前人的结果作了比较.     

Ionic liquids from the cationic cobalt(III) Schiff base complex, [Co(acacen)L2][Tf2N] (acacen = N,N′-bis(acetylacetone)ethylenediamine,Tf2N = bis(trifluoromethanesulfonyl)amide)

Ionic liquids comprising cationic cobalt(III) complexes [Co(acacen)L₂][Tf₂N] (L?=?3-butylpyridine (1), 1-butylimidazole (2); acacen?=?N,N′-bis(acetylacetone)ethylenediamine, Tf₂N?=?bis(trifluoromethanesulfonyl)amide) were prepared. 1 is a liquid at room temperature and exhibits a glass transition at ?12?°C, whereas 2 is a solid at room temperature with a melting point of 74.6?°C and glass transition temperature of ?15?°C upon cooling from the melt. These salts are reddish brown diamagnetic materials that are stable against air and water; these properties differ from those of the corresponding iron(III) salt. Desorption of the axial ligands of 1 and 2 occurs at 180 and 207?°C, respectively.     

Synthesis and characterisation of [tris(1,3-dithiole-2-thione-4,5-dithiolato)-stannate]2−, [Q]2[Sn(dmit)3], [tris(1,3-dithiole-2-one-4,5-dithiolato)stannate]2−, [Q]2[Sn(dmio)3] and [tris(1,3-dithiole-2-thione-4,5-selenolato)stannate]2−, [Q]2[Sn(dsit)3], complexes: Analysis of the structural variations of the [Sn(dmit)3]2− and [Sn(dmio)3]2− dianions

[Tris(1,3-dithiole-2-thione-4,5-dithiolato)stannate]²⁻, [Q]₂[Sn(C₃S₅)₃], [tris(1,3-dithiole-2-one-4,5-dithiolato)stannate]²⁻, [Q]₂[Sn(C₃S₄O)₃], and [tris(1,3-dithiole-2-thione-4,5-diselenolato)stannate]²⁻ [Q]₂[Sn(C₃S₃Se₂)₃], complexes, have been synthesised and characterised. Crystal structure determinations of [Q]₂[Sn(C₃S₅)₃] (Q=1,4-dimethylpyridinium, monoclinic and orthorhombic forms; NMe₄, NEt₄, and PPh₄) and [NEt₄]₂[Sn(C₃S₄O)₃] revealed variations in the overall dianion structures. The geometry about tin in each case is essentially octahedral with the chelate bite angles in the range 80.7(5)–87.45(4)°: the range of Sn–S distances is 2.5207(18)–2.571(17) Å. A statistical analysis, carried out on the crystal structure data for the six complexes, indicated that the most critical factors in controlling the overall shape of the dianion were the distances of the Sn atom from the dithiolate ligand planes [Sn–OOP]. Interanionic S⋯S interactions, within the sum of the van der Waals’ radii for two S atoms, are affected by the size of the cation, Q; the secondary connectivity is 3-dimensional for the smallest cations, Q=1,4-dimethylpyridinium and NMe₄, in chains for the somewhat larger cation, NEt₄ and is absent for the still larger, PPh₄ cation.     

Dinuclear Nickel(II) and Zinc(II) Complexes of 2,6-[N,N′-bis(2-hydroxyphenylmethyl)-N,N′-bis(2-pyridylmethyl)aminomethyl]-4-methylphenol

Abstract

The symmetric 'end-off' compartmental proligand 2,6-[N,N′-bis(2-hydroxy-phenylmethyl)-N,N′-bis(2-pyridylmethyl)aminomethyl]-4-methylphenol (H₃L) has been used to generate homodinuclear nickel(II) and zinc(II) complexes. The crystal structures of the complexes reveal that the di-nickel(II) complex is donor asymmetric and the di-zinc(II) complex is coordination number asymmetric. In both complexes non-coordinated acetic acid molecules are tightly hydrogen-bonded to the pendant phenols of the ligand generating a double acid salt of the type[CH₃COO…H…L…H…OOCCH₃]^3? in the dinickel complex and a single acid salt of the type [CH₃COO…H…L]^3? in the dizinc complex. In both cases the ligand periphery has been extended to provide a supraligand in which the donor potential of the original ligand has been enhanced.     

Dichlorotriethylphosphine-[N-formyl-N,N′-bis(3,4-dimethoxy)benzyl-trimethylenediamine] platinum(II)

By treatment of 1,3-bis(3,4-dimethoxybenzyl)-3,4,5,6-tetrahydropyrimidinium chloride (1) with KOBu ^t and [PtCl₂(PEt₃)₂]₂ N-coordinated platinum complex (2) is obtained. The Pt atom is coordinated in square planar arrangements by two chloride ions in a trans-configuration, the N-formyl-N,N′-bisaryltrimethylenediamine nitrogen atom, and the phosphine P atom. An extensive three-dimensional network of three C-H…O hydrogen bonds, two C-H…π and one π…π interactions are responsible for the crystal stabilization. Intermolecular hydrogen bonds and C-H…π interactions produce R ₂ ² (6), R ₂ ² (22), R ₂ ² (24), R ₃ ³ (23), R ₄ ⁴ (26), and R ₄ ⁴ (32) rings.     

Reaction products distribution between square-planar gold(III) complexes and N,N,N′,N′-tetramethylthiuram disulfide. Crystal structure of bis(N,N-dimethyldithiocarbamato)gold(III) bromide dihydrate, [Au(Me2NCS2)2]Br·2H2O

Summary The reactions of N,N,N,N-tetramethylthiuram disulfide (tmtds) with gold(III) complexes of the [Au(L)X₃] type [L = N-methylimidazole (N-Melm), 2-methylbenzoxazole (2-MeBO) and 2,5-dimethylbenzoxazole (2,5-diMeBO), X = Cl, Br or I] are reported, and yielded two main types of product - [Au(Me₂dtc)X₂] (A) and [Au(Me₂dtc)₂]X (B) (Me₂dtc = N,N-dimethyldithiocarbamato anion). The ratio of the product yields (B/A) depends upon the nature of the ligand (L) and halogen (X). The ratio B/A for the reaction: [Au(L)Cl₃] + tmtds = A + B, increases in the sequence N-MeIm < 2- MeBO < 2,5-diMeBO, which correlates well with the level of cytotoxic activity exhibited by the [Au(L)Cl₃] complexes. A and B were characterized by their i.r., u.v-vis. and ¹-n.m.r. spectra. The magnetic measurements were also recorded. The data support a squareplanar geometry for gold(III) complexes with the Me₂dtc ligand bonded in a bidentate fashion; a conjecture has been verified crystallographically for [Au(Me₂NCS₂)₂]-Br·2H₂O. The X-ray analysis confirmed that the complex is composed of ionic units: [Au(Me₂dtc)₂] ⁺ and Br^– and H₂O molecules. The Au—S distances are markedly similar, falling in the 2.343(4)–2.350(3) A range.