Vibrational spectra and electronic structure of 1-germatranol, 1,1-quasi-germatrandiole,and 1,1,1-hypogermatrantriole (HO)4−n Ge(OCH2CH2) n NR3−n (R = H,Me; n = 1–3)

IR spectra of 1-germatranol, 1,1-quasi-germatrandiole, 1,1,1-hypogermatrantriole with a general formula (HO)_4?n Ge(OCH₂CH₂) _n NR_3?n (n = 1–3) are obtained. At the B3LYP/aug-cc-pVDZ density functional level the equilibrium structures and vibrational spectra of these compounds along with their hydrogen-bonded dimers are calculated. Based on the calculations the band assignment is performed in the IR spectra of 1-germatranol, 1,1-quasi-germatrandiole, and 1,1,1-hypogermatrantriole. The existence of dimers is manifested in the IR spectra as the absence of bands in the frequency ranges characteristic of the bending vibrations of Ge-OH groups and the presence of bands in the vibrational range of hydrogen-bonded germatranyl groups.     

The photo-induced decarbonylation of Cp′M(NO)(CO)2 (M = Cr,Mo, W) with diorgano dichalcogenides (R2E2; E = S,Se; R = Me,Ph)

The photo-induced decarbonylation of CpCr(NO)(CO)₂ (1a) in MeCN solution in the presence of R₂E₂ (E = S, Se; R = Me, Ph) leads to the formation of chalcogenolato-bridged binuclear complexes Cp₂Cr₂(NO)₂(-ER)₂ [E = S; R = Me (2a), Ph (3a); E = Se, R = Me (4a), Ph (5a)] while reactions between CpM(NO)(CO)₂ [M = Mo (1b), W (1c)] and Ph₂E₂ (E = S, Se) result in mononuclear complexes CpM(NO)(EPh)₂ [M = Mo; E = S (9b), Se (10b); M = W, E = S (11c), Se (12c)]. The corresponding reactions of (1b) with Me₂E₂ (E = S, Se) yielded both mono and binuclear complexes: CpMo(NO)(SeMe)₂ (8b), Cp₂Mo₂(NO)₂(-EMe)₂ [E = S (6b), Se (7b)]. The new complexes have been characterized by i.r., ¹H-, ¹³C-n.m.r. spectra and by electron-impact mass spectrometry.     

(MN)nHm(M=Ga,In; n=1-4; m=1, 2)团簇的结构与稳定性

采用密度泛函理论(DFT)的B3LYP方法, 在6-31G**和Lanl2dz水平上分别对(MN)nHm(M=Ga, In; n=1-4; m=1, 2)进行了优化和振动频率计算. 得到了上述团簇的最稳定构型、H原子的结合能以及它们的能隙. 结果表明, (MN)nH(M=Ga, In; n=1-4)的基态构型均为双重态, (MN)nH2(M=Ga, In; n=1-4)的基态构型均为单重态; 当氢的个数为1时, 加在N原子上比加在M(M=Ga, In)原子上稳定, 如有N3单元, 那么加在N3单元两侧的构型是相同的, 且它是最稳定的; 当氢的个数为2时, 除n=1外, 分别加在两个N原子上的构型是最稳定的, 如有N3单元, 那么分别加在N3单元分离最远的两个N原子的构型是最稳定的. GaNH、(GaN)3H 和InNH的结合能和能隙都很大, 说明这些团簇都有很高的稳定性.     

The chemistry of [Ru(trpy)(Q)X]n+ (trpy = 2,2′2″-terpyridine; Q = the quinolin-8-olate anion; X = Cl-, H2O,MeCN and N-_3; n = 0 and 1)

Reaction of [Ru(trpy)Cl₃] with quinolin-8-ol (HQ) yields [Ru(trpy)(Q)Cl]. Treatment of [Ru(trpy)(Q)Cl] with Ag⁺ in Me₂CO–H₂O (3:1) and MeCN gives [Ru(trpy)- (Q)(H₂O)]⁺ and [Ru(trpy)(Q)(MeCN)]⁺, respectively, which were isolated as their perchlorate salts. A similar reaction in EtOH, in the presence of NaN₃, yields [Ru(trpy)(Q)(N₃)]. All complexes are diamagnetic (low-spin, d⁶, S = 0) and show many intense m.l.c.t. transitions in the visible region. They display a reversible Ru^II-Ru^III oxidation in the -0.13-0.48 V versus s.c.e. range, followed by an irreversible Ru^III-Ru^IV oxidation in the 0.46–1.08V versus s.c.e. range and three trpy-based reductions on the negative side of s.c.e. Chemical oxidation of [Ru^II(trpy)(Q)Cl] by Ce⁴⁺ gives [Ru(trpy)-(Q)Cl]⁺ which shows intense l.m.c.t. transitions in the visible region together with a weak ligand field transition in the lower energy region. The complex is one-electron paramagnetic (low-spin, d⁵, S=1/2) and shows a rhombic e.s.r. spectrum in MeCN–PhMe (1:1) solution at 77K. Chemical oxidation of [Ru(trpy)(Q)-(H₂O)]⁺ results in the formation of a -oxo dimer, [{Ru(trpy)(Q)}₂O]²⁺.     

Syntheses and X-ray Characterization of Novel [M4(H2O)2(XW9O34)2] n− (M=CuII, X=CuII; and M=FeIII, X=FeIII) Polyoxotungstates

Two novel examples of sandwich type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Na₁₃[H₃Cu₄(H₂O)₂(CuW₉O₃₄)₂]39H₂O (1) and Na₉K[Fe₄(H₂O)₂(FeW₉O₃₄)₂]32H₂O (2) were prepared in aqueous solution by reaction of sodium tungstate with Fe^III and Cu^II cations, respectively. 1 crystallizes in the monoclinic space group P2₁/n (a=13.054(3) Å, b=17.729(4) Å, c=20.998(4) Å, =93.50(3)°), while 2 is triclinic, space group P¯1 (a=12.316(2) Å, b=13.716(3) Å, c=14.925(3) Å, =99.36(3)°, =104.21(3)°, =101.55(3)°). Each anion consists of two [XW₉O₃₄] ^n– moieties (X=Fe^III, n=11 (1) and Cu^II, n=12 (2)) which can be described as -B-isomers of the defect Keggin anion. These units are linked via a belt of four Fe^IIIO₆ or Cu^IIO₆ groups. Two transition metal atoms fill their octahedral coordination sphere with one additional water ligand.     

Stabilities,Electronic Structures,and Bonding Properties of Iron Complexes (E1E2)Fe(CO)2(CNArTripp2)2 (E1E2=BF,CO, N2, CN−, or NO+)**

The coordination of 10-electron diatomic ligands (BF, CO N₂) to iron complexes Fe(CO)₂(CNAr^Tripp2)₂ [Ar^Tripp2=2,6-(2,4,6-(iso-propyl)₃C₆H₂)₂C₆H₃] have been realized in experiments very recently (Science, 2019 , 363, 1203–1205). Herein, the stability, electronic structures, and bonding properties of (E₁E₂)Fe-(CO)₂(CNAr^Tripp2)₂ (E₁E₂=BF, CO, N₂, CN⁻, NO⁺) were studied using density functional (DFT) calculations. The ground state of all those molecules is singlet and the calculated geometries are in excellent agreement with the experimental values. The natural bond orbital analysis revealed that Fe is negatively charged while E₁ possesses positive charges. By employing the energy decomposition analysis, the bonding nature of the E₂E₁–Fe(CO)₂(CNAr^Tripp2)₂ bond was disclosed to be the classic dative bond E₂E₁→Fe(CO)₂(CNAr^Tripp2)₂ rather than the electron-sharing double bond. More interestingly, the bonding strength between BF and Fe(CO)₂(CNAr^Tripp2)₂ is much stronger than that between CO (or N₂) and Fe(CO)₂(CNAr^Tripp2)₂, which is ascribed to the better σ-donation and π back-donations. However, the orbital interactions in CN⁻→Fe(CO)₂(CNAr^Tripp2)₂ and NO⁺→Fe(CO)₂(CNAr^Tripp2)₂ mainly come from σ-donation and π back-donation, respectively. The different contributions from σ donation and π donation for different ligands can be well explained by using the energy levels of E₁E₂ and Fe(CO)₂(CNAr^Tripp2)₂ fragments.     

Generation and characterization of C60(CN)2n−(n=1,2,3)

The mono-anion, di-anion and tri-anion of dicyanodihydrofullerene [C₆₀(CN)₂] have been generated and monitored with a thin-layer spectro-electrochemical cell. The characteristic NIR absorption bands are found to be at 1019, 875 as well as at 744, and 691 nm for C₆₀(CN)₂⁻, C₆₀(CN)₂²⁻ and C₆₀(CN)₂³⁻, respectively. Density functional theory calculations indicate that these anions exhibit no Jahn–Teller effect and possess charge distributions and shape distortions that are different from C₆₀ⁿ⁻(n=1,2,3) upon negative charge addition.     

Synthesis,Crystal Structures,and Properties of (4,4'-Hbipy)2[Sn2(C2O4)3] and (4,4'-Hmbipy)[SnX2] (X = C2O42–, m = 2; X = Cl,m = 0; bipy = bipyridine)

Three new tin coordination compounds (4,4'-Hbipy)₂[Sn₂(C₂O₄)₃] ( 1 ), (4,4'-H₂bipy)[Sn(C₂O₄)₂] ( 2 ), and SnCl₂(4,4'-bipy) ( 3 ) were synthesized under hydro-(solvo-)thermal conditions and their crystal structures were determined by single-crystal X-ray diffraction. Compound 1 exhibits a ionic structure based on discrete [4,4'-Hbipy]⁺ cations and [Sn₂(C₂O₄)₃]^2– anions. These two units are linked via N–H ··· O hydrogen bonds to form a pseudo-one-dimensional zigzag hydrogen-bonded chain. In compound 2 , four-coordinate Sn atoms form monomeric tin dioxalato complexes, which are connected to the doubly protonated [4,4'-H₂bipy]²⁺ cations through N–H ··· O hydrogen bonded to give a one-dimensional zigzag hydrogen-bonded chain. Compound 3 forms a three-dimensional hydrogen-bonded network, in which ¹_∞[SnCl₂(4,4'-bipy)] linear chains are interconnected to each other by C–H ··· Cl hydrogen bonding. The solid-state UV/Vis/NIR diffuse reflectance spectroscopy shows that three compounds are broadband semiconductors. The thermogravimetric analysis evidences the thermal stability of the three compounds up to 175, 201, and 246 °C, respectively.     

Molecular Ln(III)−H−E(II) Linkages (Ln=Y,Lu; E=Ge,Sn, Pb)

Following the alkane-elimination route, the reaction between tetravalent aryl tintrihydride Ar*SnH₃ and trivalent rare-earth-metallocene alkyls [Cp*₂Ln(CH{SiMe₃}₂)] gave complexes [Cp*₂Ln(μ-H)₂SnAr*] implementing a low-valent tin hydride (Ln=Y, Lu; Ar*=2,6-Trip₂C₆H₃, Trip=2,4,6-triisopropylphenyl). The homologous complexes of germanium and lead, [Cp*₂Ln(μ-H)₂EAr*] (E = Ge, Pb), were accessed via addition of low-valent [(Ar*EH)₂] to the rare-earth-metal hydrides [(Cp*₂LnH)₂]. The lead compounds [Cp*₂Ln(μ-H)₂PbAr*] exhibit H/D exchange in reactions with deuterated solvents or dihydrogen.     

Can Aromaticity Coexist with Diradical Character? An Ab Initio Valence Bond Study of S2N2 and Related 6π‐Electron Four‐Membered Rings E2N2 and E42+ (E=S,Se, Te)

A series of 6π‐electron 4‐center species, E₂N₂ and E₄²⁺ (E=S, Se, Te) is studied by means of ab initio valence bond methods with the aims of settling some controversies on 1) the diradical character of these molecules and 2) the radical sites, E or N, of the preferred diradical structure. It was found that for all molecules, the cumulated weights of the two possible diradical structures are always important and close to 50 %, making these molecules comparable to ozone in terms of diradical character. While the two diradical structures are degenerate in the E₄²⁺ dications, they have on the contrary strongly unequal weights in the E₂N₂ neutral molecules. In these three molecules, the electronic structure is dominated by one diradical structure, in which the radical sites are the two nitrogen atoms, while the other diradical structure is much less important. The ordering of the various VB structures in terms of their calculated weights is confirmed by the relative energies of individual VB structures. In all cases, the major diradical structure (or both diradical structures when they are degenerate) is (are) the lowest one(s), while the covalent VB structures lie higher in energy. The vertical resonance energies are considerable in S₂N₂ and S₄²⁺, about 80 % of the estimated value for benzene, and diminish as one goes down the periodic table (S→Se→Te). This confirms the aromatic character of these species, as already demonstrated for S₂N₂ on the basis of magnetic criteria. This and the high weights and stabilities of one or both diradical structures in all systems indicates that aromaticity and diradical character do not exclude each other, contrary to what is usually claimed. Furthermore, it is shown that the diradical structures find their place in a collective electron flow responsible for the ring currents in the π system of these species.     

Carbene complexes of molybdenum and tungsten Et3E-CH=M(NAr)(OR)2 (M = Mo, W; E = Si, Ge) and π-complex of molybdenum (RO)2(ArN)Mo(CH2=CH-GeEt3). Synthesis and catalytic properties

The heteroelement-containing alkylidene imide complexes with molybdenum and tungsten Et₃SiCH=Mo(NAr)(OR)₂ (I), Et₃ ECH=W(NAr)(OR)₂ (E = Si (II), Ge (III); Ar = 2,6-i-Pr₂C₆H₃; R=CMe₂ CF₃) and π-complex (RO)₂(ArN)Mo(CH₂=CH-GeEt₃) (IV) were synthesized by the reaction of Alkyl-CH=M(NAr) (OR)₂ (M=Mo, W; Alkyl = t-Bu, PhMe₂C) with organosilicon and organogermanium vinyl reagents Et₃ECH=CH₂ (E = Si, Ge). The structure of compounds I–III was determined by X-ray diffraction (XRD). The complexes I–IV are active initiators of metathesis polymerization of cycloolefins.     

Interactions of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1)

The coupled cluster singles and doubles method with perturbative treatment of triple excitations is applied to calculate the potentials of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1). The bond functions and the basis set superposition errors are considered to obtain accurate interaction energies. The potential energy curves of all complexes are obtained. The vibrational energy levels and the spectroscopic parameters for these complexes are determined. The analytical potential energy functions are also fitted based on the potential energies.     

M≡E and M=E Complexes of Iron and Cobalt that Emphasize Three-fold Symmetry (E = O, N, NR)

Mid-to-late transition metal complexes that feature terminal, multiply bonded ligands such as oxos, imides, and nitrides have been invoked as intermediates in several catalytic transformations of synthetic and biological significance. Until about ten years ago, isolable examples of such species were virtually unknown. Over the past decade or so, numerous chemically well-defined examples of such species have been discovered. In this context, the presentreview summarizes the development of 4- and 5-coordinate Fe(E) and Co(E) species under local three-fold symmetry.     

HoCl~3-MCl~n体系相图的研究(M=Li, Mg, Ca, Pb; n=1, 2)

借助于DTA与X射线衍射法研究了HoC_3-MCl_n(M=Li,Mg,Ca,Pb;n=1或2)二元体系相图.发现HoCl_3-LiCl体系相图属固液异组成型,有一化合物Li_3HoCl_6生成,且在483℃有一相转变.其无变点分别为p(34.0mol%HoCl_3,506℃)和e(50.5mol％HoCl_3,452℃); 而HoCl_3-MgCl_2,CaCl_2,PbCl_2。体系皆属简单低共熔型相图.其低共熔点e的组成与温度分别为:50.0mol％HoCl_3(580℃)、49.0mol％HoCl_3(541℃)和37.0mol％HoCl_3(422℃).HoCl_3-PbCl_2体系在固相下有一不稳定化合物PbHoCl_5生成,在408℃分解.同时探讨了RECl_3-LiCl相图的某些规律。     

HoCl~3-MCl~n体系相图的研究(M=Li,Mg, Ca,Pb; n=1, 2)

借助于DTA与X射线衍射法研究了HoCl~3-MCl~n(M=Li, Mg, Ca, Pb; n=1或2)二元体系相图, 发现HoCl~3-LiCl体系相图属固液异组成型, 有一化合物Li~3HoCl~6生成, 且在483℃有一相转变。其无变点分别为p(34.0mol%HoCl~3, 506℃)和e(50.5mol%HoCl~3, 452℃); 而HoCl~3-MgCl~2, CaCl~2, PbCl~2体系皆属简单低共熔型相图。其低共熔点e的组成与温度分别为: 50.0mol%HoCl~3(580℃)、49.0mol%HoCl~3(541℃)、37.0mol%HoCl~3(422℃)。HoCl~3-PbCl~2体系在固相下有一不稳定化合物PbHoCl~5生成, 在408℃分解, 同时探讨了RECl~3-LiCl相     

Syntheses of (C_5H_9C_5H_4)_2LnCl(THF)_n (Ln=Nd, Sm, Er, Yb) and crystal structure of [(C_5H_9C_5H_4)_2-LnCl(THF)_n]_2(Ln=Sm, n=1; Ln=Er, n=0)

Reactions of lanthanoid trichlorides with sodium cyclopentylcyclopentadienyl in THFafford bis(cyclopentylcyclopentadienyl) lanthanoid chloride complexes (C_5H_9C_5H_4)_2LnCl(THF)_n (Ln=Nd, Sm, n=1; Ln= Er, Yb, n= 0). The compound [CP'_2SmCl(THF)]_2 (2) (Cp' =cyclopentylcy-clopentadienyl) crystallizes from mixed solvent of hexane and THF in monoclinic space group P_2_1/cwith a = 11.583 (3), b = 23.019(6), c = 8.227 (2), β= 90.26 (2)°, V= 2194 (1)~3, D_c= 1.59 g/cm~3.μ= 28.6 cm~(-1), F(000) = 1060, Z= 2 (dimers). Its crystal molecule is a dimer with a crystallographicsymmetry center. The central metal atom Sm is coordinated to two Cp' rings, two bridging chlorineatoms and one THF forming a distorted trigonal bipyramid. The crystal of [Cp'_2ErCl]_2 (3) belongs tothe triclinic space group P with a = 11.264 (2), b= 13.296(5), c = 14.296(6), a = 96.99 (3), β=112.47(2), γ= 102.78(2)°, V= 1865(1)~3, D_c= 1.67 g /cm~3, μ= 48.0 cm~(-1), F(000) = 924, Z = 2 (dimers).The molecule is a dimer consisting of two Cp'_2 ErCl species bridged by two Cl atoms. The centralmetal atom Er is coordinated to two Cp' rings and two bridging chlorine atoms forming a pseudo-tetrahedron. All these complexes are soluble in THF, DME, Et_2O, toluene and hexane.     

93Nb(n,2n)92mNb, 93Nb(n,α)90mY and 92Mo(n,p)92mNb reactions at 14.78 MeV and covariance analysis

Journal of Radioanalytical and Nuclear Chemistry - The cross sections for the 93Nb(n,2n)92mNb, 93Nb(n,α)90mY and the 92Mo(n,p)92mNb reactions have been measured with respect to the...     

Syntheses and Crystal Structures of Two Nickel(II) Complexes [Ni(dmpzm)2(L)]Cl·nH2O (L = HCO2, OAc; n = 2, 3; dmpzm = 1,1'-Methylenebis(3,5-dimethyl-1H-pyrazole))

Reactions of NiCl2·6H2O with dmpzm and formic or acetic acid at PH = 7 pro- duced the two title compounds, [Ni(dmpzm)2(HCO2)]Cl·2H2O 1 and [Ni(dmpzm)2(Oac)]Cl·3H2O 2 (dmpzm = 1,1'-methylenebis(3,5-dimethyl-1H-pyrazole)). 1 and 2 were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. 1 crystallizes in the orthorhombic system, space group Pcca with a = 18.700(2), b = 8.6843(9), c = 18.098(2)(A), V = 2939.1(5)(A)3, Z = 4, Dc = 1.319 g/cm3, T = 193 K, C23H37ClN8NiO4, Mr = 583.75, F(000) = 1232, μ(MoKα) = 0.792 cm(1, S = 1.079, R = 0.0772 and wR = 0.1958 for 2265 observed reflections with I > 2σ(I). 2 crystallizes in the orthorhombic system, space group Pcca with a = 17.011(3), b = 18.630(4), c = 19.300(4)(A), V = 6117(2)(A)3, Z = 8, Dc = 1.337 g/cm3, T = 193(2) K, C24H41ClN8NiO5, Mr = 615.79, F(000) = 2608, μ(MoKα) = 0.768 cm(1, S = 1.059, R = 0.0518 and wR = 0.1109 for 5124 observed reflections with I > 2σ(I). The Ni atoms in 1 or 2 are chelated by two dmpzm ligands and one formate or acetate anion, forming slightly distorted octahedral geometries. In the crystals of 1 or 2, intermolecular hydrogen bonding interactions result in the formation of 2D hydrogen-bonded frameworks.     

Diacetylenic Derivatives of Fe2(CO)6(μ-EE′): Spectroscopic Investigations of Fe2(CO)6{μ-EC(H) = C(C≡ CMe)E′} (E = E′, E ≠ E′; E, E′ = S, Se, Te)

The diacetylenic adducts, Fe₂(CO)₆{-EC(H) = C(C CMe)E} (E = E, E E; E, E = S, Se, Te) (1–8) have been obtained from the room temperature stirring of Fe₂(CO)₆(-EE) with HC CC CMe in methanol solvent containing sodium acetate. Compounds 1–8 have been characterized by IR and multinuclear NMR (¹H, ¹³C, ⁷⁷Se, and ^l25Te) spectroscopy. Trends in the chemical shifts of ⁷⁷Se and ¹²⁵Te NMR spectra of Fe₂(CO)₆{-EC(H) = C(C CMe)E} with a variation of EE are discussed.     

Carbonate complexes [C(NH2)3]6[An(CO3)5] · nH2O (An = Th, U, Np, and Pu; n = 3 and 4): Synthesis and structures

Two series of isostructural double An(IV) and guanidinium carbonates were obtained as single crystals of the formula [C(NH₂)₃]₆[An(CO₃)₅] · nH₂O (An = Th, U, Np, and Pu; n = 3 (I) and 4 (II)) and examined by X-ray diffraction. For the Pu(IV) complexes, a = 10.490(2) Å, b = 33.798(5) Å, c = 10.519(2) Å, β = 119.414(7)°, space group P2₁/c, Z = 4, R = 0.0369 (I) and a = 16.0895(18) Å, b = 13.1458(14) Å, c = 16.6951(18) Å, β = 108.116(6)°, space group C2/c, Z = 4, R = 0.0171 (II). Both series of complexes contain the anions [An(CO₃)₅]^6?, in which the An atom is coordinated to five chelating bidenate carbonate ions. The coordination polyhedra of the An atoms are distorted bicapped square antiprisms. Within both the series, the An-O bond lengths decrease monotonically only for the sequence Th-U-Np. The average Np-O and Pu-O bond lengths in both tri- and tetrahydrates are virtually equal. The IR and electronic absorption spectra of the complexes obtained were studied. The absorption bands due to the f-f transitions experience bathochromic shifts in the spectra of the U⁴⁺ and Pu⁴⁺ carbonate complexes and hypsochromic shifts in the spectra of the Np⁴⁺ complexes.