Analysis of the metal–ligand bonds in [Mo(X)(NH2)3] (X = P, N, PO, and NO), [Mo(CO)5(NO)]+, and [Mo(CO)5(PO)]+

Quantum chemical calculations at the DFT level have been carried out for model complexes [Mo(P)(NH₂)₃] (1), [Mo(N)(NH₂)₃] (2), [Mo(PO)(NH₂)₃] (3), [Mo(NO)(NH₂)₃] (4), [Mo(CO)₅(PO)]⁺ (5), and [Mo(CO)₅(NO)]⁺ (6). The equilibrium geometries and the vibration frequencies are in good agreement with experimental and previous theoretical results. The nature of the Mo–PO, Mo–NO, Mo–PO⁺, Mo–NO⁺, Mo–P, and Mo–N bond has been investigated by means of the AIM, NBO and EDA methods. The NBO and EDA data complement each other in the interpretation of the interatomic interactions while the numerical AIM results must be interpreted with caution. The terminal Mo–P and Mo–N bonds in 1 and 2 are clearly electron-sharing triple bonds. The terminal Mo–PO and Mo–NO bonds in 3 and 4 have also three bonding contributions from a σ and a degenerate π orbital where the σ components are more polarized toward the ligand end and the π orbitals are more polarized toward the metal end than in 1 and 2. The EDA calculations show that the π bonding contributions to the Mo–PO and Mo–NO bonds in 3 and 4 are much more important than the σ contributions while σ and π bonding have nearly equal strength in the terminal Mo–P and Mo–N bonds in 1 and 2. The total (NH₂)₃Mo–PO binding interactions are stronger than for (NH₂)₃Mo–P which is in agreement with the shorter Mo–PO bond. The calculated bond orders suggest that there are only (NH₂)₃Mo–PO and (NH₂)₃Mo–NO double bonds which comes from the larger polarization of the σ and π contributions but a closer inspection of the bonding shows that these bonds should also be considered as electron-sharing triple bonds. The bonding situation in the positively charged complexes [(CO)₅Mo–(PO)]⁺ and [(CO)₅Mo–(NO)]⁺ is best described in terms of (CO)₅Mo → XO⁺ donation and (CO)₅Mo ← XO⁺ backdonation (X = P, N) using the Dewar–Chatt–Duncanson model. The latter bonds are stronger and have a larger π character than the Mo-CO bonds.     

[C, N, N, P]体系异构体结构与稳定性

在B3LYP/6-311G(d)和QCISD(t)/6-311+G(2df)水平下计算得到了[C, N, N, P]体系的9个异构体、20个过渡态及一些相关的解离碎片, 并研究了异构体之间的异构化过程, 讨论了该体系异构体的结构与稳定性. 结果表明在得到的9个异构体中, 具有2A′电子态的、非线型链状NCNP, NCPN, CNPN和CNNP 4个异构体是较稳定的. 其余异构体由于易于重排或是解离, 稳定性较低. 研究同时给出了这4个异构体的振动频率、转动常数、偶极矩、第一绝热电离能和绝热电子亲合能等相关数据, 为可能的实验和星际光谱观测提供相关的理论数据. 得到的计算结果与等价电子体系SiNNP进行了比较.     

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.     

Photoredox-catalyzed C(sp2)–N coupling reactions

Photoredox-catalyzed radical reactions have attracted intense interest from synthetic chemists over the past several years. The photoredox-catalyzed C(sp²)–N coupling reactions, including Ullmann type C–N coupling (C–X/N–H type coupling), redox neutral C–N coupling (C–H/N–X type coupling) and oxidative C–N coupling (C–H/N–H type coupling), have been summarized in this digest.     

Can bridged 1,6-X-[10]annulenes (X = SiH(2), SiMe(2), PH,and S) exist?

[structure: see text] In contrast to the 1,6-X-[10]annulenes (X = CH(2), O, NH) with delocalized forms (c), their X = PH and S counterparts favor the bisnorcaradiene structures (b). Forms b and c are close in energy with X = SiH(2) and SiMe(2). The computed nucleus independent chemical shifts (NICS), show both annulenes (c) and cyclic polyenes (a) to be aromatic. Strain-introduced structural localization, e.g., due to four bulky SiMe(3) substituents, reduces but does not eliminate aromaticity.     

Struktur von [CPRu(C0)2]2 (Cp  η5-pentamethylcyclopentadienyl)

The molecular structure of di-μ-carbonyl-bis[carbonyl(η⁵-pentamethylcyclopentadienyl)ruthenium] (RuRu) has been determined by a single-crystal X-ray diffraction study (monoclinic, space group P2₁/n,a  979.90(9), b = 831.91(7), c = 1427.75(12) pm, β = 100.026(9)°, R = 0.018). In the solid state the complex exists solely as the trans-carbonyl bridged isomer. The RuRu bond length is 275.2(1) pm.     

Infrared and Raman spectroscopic investigations of methylammonium haloantimonates(III), [N(CH3)4−nHn]3 Sb2X9 (n = 0–3, X = Cl or Br), through their phase transitions

Infrared and Raman spectra of methylammonium chloroantimonates(III) of the general formula [N(CH₃)_4−nH_n]₃Sb₂Cl₉ with n = 0, 1, 2 and 3 and of the methylammonium bromoantimonate(III), (CH₃NH₃)₃Sb₂Br₉, have been investigated in detail across their phase transitions. Vibration modes due to CH₃ deformation and those involving the NH_n (n = 1, 2 and 3) groups show significant changes across the phase transitions of the chloroantimonates, besides those due to the Sb₂Cl₉ anion. The anion modes differ with the number of CH₃ groups since the nature of the anion itself changes, the free anion being present only in the quarternary compound. The high-temperature phases of the chloroantimonates seem to involve random orientations of the methylamino groups; a plastic-type state clearly manifests itself in the trimethyl and the tetramethylamino derivatives. A phase transition is predicted in all the chloroantimonates below 150 K, based on the changes in the anion bands at low temperatures. Changes in the IR and Raman spectra accompanying the phase transitions of (CH₃NH₃)₃Sb₂Br₉ and (CH₃NH₃)₃Bi₂Br₉ are similar and in the high-temperature phase of these compounds the (CH₃NH₃)⁺ cations ard oriented randomly.     

Synthesis,characterization, spectral studies and antifungal activity of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3,3′-bis[N,N,di(carboxymethyl)-aminomethyl]- o -cresol sulphonphthalein

Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of the type Na₄[ML(H₂O)₂] of the ligand, 3,3′-bis[N,N-di(carboxymethyl)-aminomethyl]-o-cresol sulphonphthalein (Xylenol Orange, Na₄H₂L), have been synthesized and characterized by different physico-chemical (elemental analyses, solubility, electrolytic conductances, magnetic susceptibility measurements) and spectral (u.v.-vis, i.r., e.s.r., and powder X-ray diffraction) techniques for their structure determination. The data suggest 1?:?1 (M?:?L) compositions and octahedral geometries around M(II) except for Cu(II). Antifungal activity of the complexes measured against ten fungi show significant activity against Alternaria brassicicola, Alternaria solanai, Cercospora species and Helminthosporium oryzae and moderate antifungal activity against Curvularia species, Curvularia lunata, Curvularia penniseti, Colletotrichum capsici, Aspergillus niger, Aspergillus flavus Erysiphae pisi and Fusarium udum fungi.     

Direct Synthesis of Disubstituted 3-Isoquinolinone Derivatives through the Construction of C−N,C=O,and C(sp2)−C(sp3) Bonds under Transition-Metal-Free Conditions

The efficient three-component cascade coupling reaction of 3-haloisoquinolines, haloalkanes, and sp³-carbon nucleophiles (acetophenone or nitromethane) led to a series of structurally novel 1,2-disubstituted-3-isoquinolinones through the formation of C(sp³)−C(sp²), C−N, and C=O bonds. The NaOAc-promoted reaction described in this work is simple to operate, environment friendly, and highly selective.     

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.     

The first decaruthenium hydrido cluster: synthesis and crystal structure of [N(PPh3)2]2[Ru10C(CO)24]·C6H14 and [N(PPh3)2][HRu10C(CO)24]

X-ray structural studies of new thermolysis products from the reaction of Ru₃(CO)₁₂ in heptane in the presence of 1,3,5-trimethylbenzene (mesitylene) confirm that they are the decaruthenium carbido-cluster dianion [Ru₁₀C(CO)₂₄]²⁻ (I) and the hydrido decaruthenium carbido-cluster monoanion [HRu₁₀C(CO)₂₄]⁻ (II). Both anions have the giant tetrahedron Ru₁₀ metal framework, and the monohydride provides the first example of a hydrido ligand in a tetrahedral Ru₄ cavity.     

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.     

Kinetics of the oxidation of [N-(2-hydroxyethyl)-ethylene-diamine-N,N′,N′-triacetato]cobalt(II) by N-bromosuccinimide

The kinetics of the oxidation of [N-(2-hydroxyethyl)-ethylene-diamine-N,N,N-triacetato] cobalt(II), [Co^II-(HEDTA)]^–, by N-bromosuccinimide, NBS, have been studied in aqueous solutions and water-methanol solvent mixtures under various conditions. The reaction stoichiometry indicates that one mole of NBS reacts with one mole of [Co^II(HEDTA)]^–. In aqueous solutions the reaction obeys the following rate law:

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.     

NbX(X=C,N,O)的能带结构研究

本文采用EHT近似下的紧束缚能带方法,计算了NbX(X=C,N,O)的能带结构。结果表明,它们的能带结构相近,Nb—X间存在较强的成键作用,传导电子主要具有Nb的4d特征,Nb—Nb键与超导电性相关,从C到N,Nb—Nb键共价性削弱,Tc提高。尽管计算所得NbO中Nb—Nb键强度介于NbC和NbN之间,但其实际Tc却比NbC和NbN的都低,这是NbO的空位效应所致,这一结果可从我们对有序缺陷的Nb_(0.75)O_(0.75)晶体能带结构的计算得到验证。     

An investigation of the crystalline structure of the quasi-two-dimensional metamagnet of composition [C6H22N4]4+[CuCl4]Cl2 (I), with [C6H22N4]4+=[1,4,7,10-tetraazadecane]·4HC1

[C₆H₂₂N₄]⁴⁺[CuCl₄ ^2–]Cl₂ (I) crystallizes in the monoclinic space groupP2₁/c with cell constantsa=15.573(2) Å,b=7.281(2),c=7.092(2),=91.496(14)°,V= 803.874 ų, andd(z= 2 mol/cell)=1.762 gm cm^–3. Data were collected in the range 4° 2 50°, for a total of 2662 reflections, of which 2201 were independent and hadI 3(I). These were used in the solution and refinement of the structure. TheF(hkl) _obs were corrected for absorption (=23.558 cm^–1) using Psi scan curves of eight suitable reflections, leading to relative transmission coefficient adjustments ranging from 0.9999 to 0.5722. Structural refinement converged atR(F)= 0.023 and R _W (F)=0.026. The coordination around the metal consists of polymeric, axially elongated, six-bonded, trigonal antiprismatic CuCl₆ species, not the hoped for, discrete, molecular CuCl₆ ^4– species implied by their chemical formulation. The crystalline lattice contains three different types of ions: the (C₆H₂₂N₄)⁴⁺ cation, a pair of Cl^– anions which are hydrogen bonded to the secondary ammonium (-NH₂ ⁺-) hydrogens of the cation, and a CuCl₄ ^2– anion. The latter is polymerized into two-dimensional sheets linked to each other by the agency of the cations, in which the two sets of terminal (-NH₃ ⁺) hydrogen bond to the axial Cl^– ligands. The Cu-Cl distances are 2.279, 2.315, and 2.847 Å. The distance between nearest coppers in adjacent sheets is 15.573(2)Å, the length of thea-axis. The magnetic behavior of the compound is that of a metamagnet, which requires a somewhat unusual set of conditions and is very rare in Cu²⁺ compounds. Comparison of the magnetic behavior of (I) with that of related compounds is made. The thermal behavior of (I) was studied using differential scanning calorimetric measurements in the range of 120 K to its melting(dec) point (463 K). It undergoes a phase transition from green (low temperature phase) to golden yellow (room temperature phase) at 168 K, another phase transition (golden yellow to red) at 340.6 K, and another at 383.2 K during which there is not evident color change. Finally, it melts with decomposition at ca. 463 K.     

Copper(I) halide complexes with ethylenediaminium L0(H+)2, N,N,N′,N′-tetraallylethylenediaminium L4(H+)2, and N,N,N,N′,N′-pentaallylethylenediaminium L5(H+). Synthesis and crystal structures of the complexes [L0(H+)2]0.5CuCl2, [L0(H+)2]0.5CuBr1.67Cl0.33, [{L4(H+)2}0.5Cu2Cl3], and [L5(H+)Cu4Br6]

Alkylation of ethylenediamine with allyl bromide in the presence of NaHCO₃ in benzene-ethanol and acetone-ethanol gave N,N,N′,N′-tetraallylethylenediamine L⁴ and N,N,N,N′,N′-pentaallylethylenediaminium bromide (L₅(H⁺)Br₂), respectively. The ac electrochemical synthesis at copper wire electrodes in solutions of copper(II) halide and an appropriate ligand yielded single crystals of Cu(I) complexes with ethylenediaminium ([L⁰(H⁺)₂]_0.5CuCl₂ (I) and [L⁰(H⁺)₂]_0.5CuBr_1.67Cl_0.33 (II)) and its N-allyl derivatives N,N,N′,N′-tetraallylethylenediaminium ([{L⁴(H⁺)₂}_0.5Cu₂Cl₃] (III)) and N,N,N,N′,N′-pentaallylethylenediaminium ([L⁵(H⁺)Cu₄Br₆] (IV)). The crystal structures of complexes I–IV were determined by X-ray diffraction. The isostructural crystals of complexes I and II are triclinic, space group P $ \bar 1 $ , Z = 2. For I: a = 5.936(3), b = 6.387(3), c = 7.126(4) Å, α = 67.82(4)°, β = 72.98(4)°, γ = 67.55(4)°, V = 227.7(2) ų. For II a = 6.110(3), b = 6.657(3), c = 7.309(3) Å, α = 68.40(3)°, β = 72.38(3)°, γ = 67.23(3)°, V = 250.4(2) ų. In structures I and II, the organic cations are between infinite anionic chains (Cu ₂ ^? ) _n . The crystals of π-complex III are triclinic, space group P $ \bar 1 $ , a = 6.851(4), b = 8.729(4), c = 9.960(4) Å, α = 98.25(3)°, β = 102.29(3)°, γ = 107.30(3)°, V = 541.8(5) ų, Z = 2. In structure III, all the four allyl groups are π-coordinated by the metal atoms of four discrete anions Cu₄Cl ₆ ^2? . The crystals of π-complex IV are monoclinic, space group C2/c, a = 15.228(5), b = 17.095(6), c = 20.182(6) Å, β = 92.43(4)°, V = 5249(3) ų, Z = 8. Only two of five allyl groups at the same N atom are coordinated by copper(I) atoms. Structure IV contains a complex inorganic fragment of the formula (Cu₄Br ₆ ^2? ) _n .     

Mixed Amidohalotantalates [Ta(NMe2)3X3]– (X = F,Cl)

Russian Journal of Coordination Chemistry - The anionic tantalum complex (ItBuH)[Ta(NMe2)3Cl3] (I) is synthesized by the reaction of [Ta(NMe2)3Cl2]2 with N-heterocyclic carbene ItBu and is isolated...     

Reactivity of Sodium Pentaphospholide Na[cyclo-P5] towards C≡E (E=C,N, P) Triple Bonds

A diglyme solution of Na[cyclo-P₅] ( 1 ) reacts with alkynes and isolobal nitriles and phosphaalkynes to afford the otherwise elusive (aza)phospholide anions 2 a – c , 4 a,b , and 6 . The reaction of Na[cyclo-P₅] with alkynes and nitriles was studied by means of DFT methods, which suggested a concerted mechanism for the formation of 2 a and 4 b . The anions 2 a – c , 4 a,b , and 6 coordinate in an η⁵-fashion towards Fe^II to give the sandwich (aza)phosphametallocenes 3 a – c , 5 a,b and 7 in moderate to good yields. The new compounds were characterized by means of multinuclear NMR spectroscopy, single-crystal X-ray diffraction and cyclic voltammetry.