1,4-shifts in a dinuclear Ni(I) biarylyl complex: a mechanistic study of C-H bond activation by monovalent nickel

The known aryne complex (PEt3)2Ni(eta2-C6H2-4,5-F2) (1a) reacts with a catalytic amount of Br2Ni(PEt3)2 over 1% Na/Hg to afford the dinuclear Ni(I) biarylyl complex [(PEt3)2Ni]2(mu-eta1:eta1-3,4-F2C6H2-3',4'-F2C6H2) (2a), which results from a combination of C-C bond formation and C-H bond rearrangement. The dinuclear benzyne [(PEt3)2Ni]2(mu-eta2:eta2-C6H2-4,5-F2) (3) was obtained by the reaction of 1a with a stoichiometric amount of Br2Ni(PEt3)2 over excess 1% Na/Hg, and 3 was found to catalyze the conversion of 1a to 2a. The reaction of 1a with B(C6F5)3 produced the trinuclear complex (PEt3)3Ni3(mu3:eta1:eta1:eta2-4,5-F2C6H2)(mu3:eta1:eta1:eta2-4,5-F2C6H2-4',5'-F2C6H2) (6). The addition of PEt3 to 6 produced 1 equiv of 1a and 1 equiv of [(PEt3)2Ni]2(mu-eta1:eta1-4,5-F2C6H2-4',5'-F2C6H2) (7a). Both 6 and 7a were identified as intermediates in the conversion of 1a to 2a. The analogue [(PEt3)(PMe3)Ni]2(mu-eta1:eta1-4,5-F2C6H2-4',5'-F2C6H2) (7b) was prepared by the addition of PMe3 to 6 and was structurally characterized. NMR spectroscopic evidence identified the additional asymmetric biarylyl [(PEt3)2Ni]2(mu-eta1:eta1-4,5-F2C6H2-3',4'-F2C6H2) (8a) during the conversion of 1a to 2a. The initial observation of 2 equiv of 8a for every equivalent of 2a produced from solutions of 7a suggests that 8a and 2a are formed from a common intermediate. A crossover labeling experiment shows that the C-H bond rearrangement steps in the conversion of 1a to 2a occur with the intermolecular scrambling of hydrogen and deuterium labels. The evidence collected suggests that Ni(I) complexes are capable of activating aromatic C-H bonds.     

Experimental studies of the dynamics of the bond-forming reactions of CF2(2+) with H2O using position-sensitive coincidence spectroscopy

The dynamics of the product channels forming OCF(+)+H(+)+HF and HCF(2) (+)+H(+)+O following the collisions of CF(2) (2+) with H(2)O have been investigated with a new position-sensitive coincidence experiment at a center-of-mass collision energy of 5.6 eV. The results show the formation of OCF(+) occurs via the formation of a doubly charged collision complex [H(2)O-CF(2)](2+) which subsequently undergoes a charge separating dissociation to form H(+) and HOCF(2) (+). The HOCF(2) (+) monocation subsequently fragments to form HF+OCF(+). The lifetimes of the collision complex and the HOCF(2) (+) ion are at least of the order of their rotational period. The kinetic energy release in this reaction indicates that it involves the ground state of CF(2) (2+) and forms the ground electronic states of OCF(+) and HF. The mechanism for forming HCF(2) (+) involves the direct and rapid abstraction of a hydride ion from H(2)O by CF(2) (2+). The resulting OH(+) ion subsequently fragments to H(+)+O, on a time scale at least comparable with its rotational period.     

Fe2O3—SnO2复合气敏材料的气敏性能研究

本文采用共沉淀方法制备超微粒子原料粉,测试了不同配比材料的气敏灵敏度,并探讨了不同粒度的Fe_2O_3原料与气敏特性之间的关系,提出Fe_2O_3-SnO_2复合气敏材料的气敏机制属体控制与表面控制兼有的混合机制·Fe_2O_3-SnO_2,复合气敏材料,选用CuO掺杂,可制出对乙炔具有高选择性和灵敏度的气敏元件。     

H_2O_2氧化N_2生成N_2O和H_2O机理的研究

采用量子化学计算方法研究了Ｈ２Ｏ２ 氧化Ｎ２ 生成Ｎ２Ｏ 和Ｈ２Ｏ 的机理．结果发现, Ｈ２Ｏ２ 氧化Ｎ２ 先通过１ 个四元环过渡态形成中间体Ｈ２Ｎ２Ｏ２ 分子,Ｈ２Ｎ２Ｏ２ 再通过一个五元环过渡态形成Ｎ２Ｏ和Ｈ２Ｏ．根据计算得到的每步反应的活化能,得知Ｈ２Ｏ２ 氧化Ｎ２ 生成中间体Ｈ２Ｎ２Ｏ２ 分子是整个反应的控制步骤．     

NaRuO2 and NaxRuO2.yH2O: new oxide and oxyhydrate with two dimensional RuO2 layers

The new oxide and oxyhydrate NaRuO2 and NaxRuO2.yH2O (x = 0.22, y = 0.45) have been characterized. NaRuO2 is isostructural with alpha-NaFeO2. The symmetry is rhombohedral (R3m space group) with lattice parameters of a = 3.018(2) A and c = 16.493(3) A. The structure has been refined by the Rietveld method. The oxyhydrate NaxRuO2.yH2O has been prepared by stirring a sample of NaRuO2 in water at ambient temperature. NaxRuO2.yH2O crystallizes in the space group R3m with lattice parameters of a = 2.930(2) A and c = 21.913(5) A. The structure is related to the CuFeO2 3R polytype structure with the AABBCC sequence of the oxygen close packed layers along the c-axis. Analogies with the related cobalt phases are discussed. The susceptibilities of NaRuO2 and NaxRuO2.yH2O are small and constant in a large temperature range.     

MRCI investigation of different isomers of Ni2O2H2(+)

The geometrical and electronic structures of different isomers of Ni(2)O(2)H(2)(+) are investigated by multireference configuration interaction (MRCI) calculations using natural atomic orbital basis sets. The lowest-lying isomer, Ni(2)(OH)(2)(+), has a rhombic shape with two OH groups bridging the Ni atoms. The next isomer in energetic order with a relative energy of 0.29 eV consists of a linear NiONi(OH(2))(+) chain. Other structures with a rhombic shape, (NiH)(2)O(2)(+), with H bound to the Ni atoms have considerably higher energies, above 4 eV. Especially the low-lying isomers are characterised by a large number of low-lying electronic terms. The product Ni(2)O(2)H(2)(+) of the reaction of Ni(2)O(2)(+) with small alkanes is likely to have the rhombic Ni(2)(OH)(2)(+) structure. The reaction energy of the reaction Ni(2)O(2)(+) + H(2)→ Ni(2)(OH)(2)(+) is estimated to be about -3.5 eV.     

Active-site models for iron hydrogenases: reduction chemistry of dinuclear iron complexes

Reduction of Fe2(mu-S2C3H6)(CO)6 (1) in tetrahydrofuran with 1 equiv of decamethylcobaltocene (Cp*2Co) affords a tetranuclear dianion 2. The IR spectra of samples of 2 in solution and in the solid state exhibit a band at 1736 cm(-1), suggestive of the presence of a bridging carbonyl (CO) ligand. X-ray crystallography confirms that the structure of 2 consists of two Fe2 units bridged by a propanedithiolate moiety formulated as [Fe2(mu-S2C3H6)(CO)5(SCH2CH2CH2-mu-S)Fe2(mu-CO)(CO)6](2-). One of the Fe2 units has a bridging CO ligand and six terminal CO ligands. The second subunit exhibits a bridging propanedithiolate moiety. One CO ligand has been replaced by a terminal thiolate ligand, replicating the basic architecture of Fe-only hydrogenases. The reduction reaction can be reversed by treatment of 2 with 2 equiv of [Cp2Fe][PF6], reforming complex 1 in near-quantitative yield. Complex 2 can also be oxidized by acids such as p-toluenesulfonic acid, regenerating complex 1 and forming H2.     

1]molybdarenophanes: strained metallarenophanes with aluminum, gallium, and silicon in bridging positions

The first [1]molybdarenophanes were synthesized and structurally characterized. The aluminum and gallium compounds [(Me2Ntsi)Al(eta6-C6H5)2Mo] (2a) and [(Me2Ntsi)Ga(eta6-C6H5)2Mo] (2b) [Me2Ntsi = C(SiMe3)2(SiMe2NMe2)] were obtained from [Mo(LiC6H5)2].TMEDA and (Me2Ntsi)ECl2 [E = Al, Ga] in analytical pure form with isolated yields of 74% (2a) and 52% (2b). The silicon-bridged species [Ph2Si(eta6-C6H5)2Mo] (2c) was synthesized from [Mo(LiC6H5)2].TMEDA and Ph2SiCl2. Compound 2c was isolated as a crystalline material in an approximately 90% overall purity, from which a single crystal was used for X-ray analysis. The molecular structures of all three [1]molybdarenophanes 2a-c were determined by single-crystal X-ray analysis. The ring-tilt angle alpha was found to be 18.28(17), 21.24(10), and 20.23(29) degrees for 2a, 2b, and 2c, respectively. Variable temperature NMR measurements of 2a and 2b (-80 to 80 degrees C; 500 MHz) showed a dynamic behavior of the gallium species 2b but not of compound 2a. The dynamic behavior of 2b was rationalized by assuming that the Ga-N donor bond breaks, inversion at the nitrogen atom occurs, and a rotation of the Me2Ntsi ligand takes place followed by a re-formation of the Ga-N bond on the other side of the gallium atom. The analysis of the signals of meta and ortho protons of 2b gave approximate values of DeltaG not equal of 59.6 and 59.1 kJ mol-1, respectively. Compound 2b reacted with [Pt(PEt3)3] to give the ring-open product [(eta6-C6H6)Mo{eta6-C6H5[GaPh(Me2Ntsi)]}] (3b). The molecular structure of 3b was deduced from a single-crystal X-ray determination. The formation of the unexpected platinum-free product 3b can be rationalized by assuming that benzene reacted with 2b in a 1:1 ratio. Through a series of 1H NMR experiments with 2b it was shown that small amounts of donor molecules (e.g., THF) in benzene are needed to form 3b; in the absence of a donor molecule, 2b is thermally stable.     

Preparation, characterization, and structural systematics of diphosphane and diarsane complexes of gallium(III) halides

The diphosphane o-C6H4(PMe2)2 reacts with GaX3 (X = Cl, Br, or I) in a 1:1 molar ratio in dry toluene to give trans-[GaX2{o-C6H4(PMe2)2}2][GaX4], the cations of which contain the first examples of six-coordinate gallium in a phosphane complex. The use of a 1:2 ligand/GaCl3 ratio produced [GaCl2{o-C6H4(PMe2)2}][GaCl4], containing a pseudotetrahedral cation, and similar pseudotetrahedral [GaX2{o-C6H4(PPh2)2}][GaX4] complexes are the only products isolated with the bulkier o-C6H4(PPh2)2. On the other hand, Et2P(CH2)2PEt2, which has a flexible aliphatic backbone, formed [(X3Ga)2{mu-Et2P(CH2)2PEt2}], in which the ligand bridges two pseudotetrahedral gallium centers. The diarsane, o-C6H4(AsMe2)2, formed [GaX2{o-C6H4(AsMe2)2}][GaX4], also containing pseudotetrahedral cations, and in marked contrast to the diphosphane analogue, no six-coordinate complexes form; a very rare example where these two much studied ligands behave differently towards a common metal acceptor. The complexes [(I3Ga)2{mu-Ph2As(CH2)2AsPh2}] and [GaX3(AsMe3)] are also described. The X-ray structures of trans-[GaX2{o-C6H4(PMe2)2}2][GaX4] (X = Cl, Br or I), [GaCl2{o-C6H4(PPh2)2}][GaCl4], [GaX2{o-C6H4(AsMe2)2}][GaX4] (X = Cl or I), [(I3Ga)2{mu-Ph2As(CH2)2AsPh2}], and [GaX3(AsMe3)] (X = Cl, Br or I) are reported, and the structural trends are discussed. The solution behavior of the complexes has been explored using a combination of 31P{1H} and 71Ga NMR spectroscopy.     

ω-氯氟烷基醇,烯烃及环氧化物的合成

本文报道在引发剂存在下, ω-氯氟烷基碘与烯丙基化合物(CH~2=CH-CH~2X, X=OH,OAC) 及乙烯基化合物CH~2=CH-OAC 发生自由基加成反应, 生成相应的加成产物Cl(CF~2)~nCH~2CHICH~2OH (2a～d), Cl(CF~2)~nCH~2CHICH~2OAC (3a～d)和Cl(CF~2)~nCH~2CHIOAC (4a～d) , 产率较好.2a～d用LiAlH~4脱碘生成Cl(CF~2)~nCH~2CH~2CH~2OH(5a～d), 反应条件温和. 2a～d与KOH-CH~3OH反应， 主要得到醇Cl(CF~2)~nCH=CHCH~2OH (6a～c), 若2a～d与NaOH-水溶液反应则得到环氧丙烷化合物. 在少量HOAC存在下， 异丙醇溶剂中， 锌粉与2a～d和3a～d反应得到消除产物Cl(CF~2)~n-CH~2CH=CH~2 (8a～d) . 4a～d与锌反应，再经KOH-CH~3OH-H~2O水解得到Cl(CF~2)~n(CH~2)~2OH(10a～d).     

CO为还原剂同时还原SO2和NO的SnO2-TiO2固溶体催化剂Ⅱ.催化剂的物理化学性质

 用XRD, XPS, CO-TPR, NH3-TPD, SO2-TPD和IR等方法表征了SnO2-TiO2固溶体催化剂的物理化学性质. 不同配比的SnO2和TiO2均可形成均一的具有金红石结构的连续固溶体,其晶粒度比单纯的SnO2或TiO2的晶粒度小. SnO2-TiO2固溶体的比表面积随SnO2含量的增大呈火山形变化,说明在SnO2-TiO2固溶体中SnO2可阻止TiO2由锐钛矿型变为金红石型过程中比表面积的减小,而TiO2则提供了维持大表面的结构框架. SnO2倾向于在固溶体表面偏析,固溶体的表面氧含量高于单纯SnO2的表面氧含量而低于单纯TiO2的表面氧含量. SnO2, TiO2和SnO2-TiO2表面含有能被CO还原的吸附氧和晶格氧,被还原的SnO2, TiO2和SnO2-TiO2的表面晶格氧的数量仅占所有晶格氧的0.001%, 说明CO只使部分晶格氧还原并生成氧阴离子空穴. TiO2表面没有酸性, SnO2和SnO2-TiO2呈微弱酸性. 经CO还原的SnO2-TiO2上存在大量的强碱中心,说明SnO2和TiO2之间发生了协同作用. SnO2-TiO2固溶体的这些物化性质均十分有利于SO2+NO+CO的氧化还原反应.     

Preparations of 2-azabicyclo[2.2.2]octa-5,7-dien-3-ones and 7-azabicyclo[4.2.0]octa-2,4-dien-8-ones from addition reactions of 2-pyridones

The low temperature photoaddition of 2-pyridone with dimethyl acetylenedicarboxylate gave a [4 + 2]-cycloadduct and a [2 + 2]-cycloadduct across the 5,6-position of 2-pyridone. Their formations were competing with a Michael reaction of the two substrates at the room temperature reaction. The reactions of other pyridones with dimethyl acetylenedicarboxylate gave [2 + 2]- and/or [4 + 2]-cycloadducts. The [2 + 2]-cycloadducts underwent an intriguing rearrangement to fused β-lactams.     

若干线型Mo-Fe-S簇合物红外光谱及其与结构关系的研究

对若干线型Mo一Fe一S簇合物[Cl2FeS2MoS2FeCl2][-2](1)、[S2MoS2FeCl2]^2^-(2)、[S2MoS2Fe(SPh)2][2-](3)、[S2MoS2FeS2Fe(SPh)2][3-](4)、[S2MoS2FeS2MoS2][3-](5)、Cl2FeS2FeCl2][2-](6)、[(PhS)2FeS2Fe(SPh)2][2-](7)的红外光谱进行了研究。通过比较它们的特征频率、结构参数和金属原子的氧化态,对νMo-St、νMo-SbνFe-Sb、νFe-SPh、νFe-Cl进行了归属。并对δS-Mo-S的归属作了初步探讨。文中讨论了MoS2Fe单元中Mo原子对νFe-Sb的影响, 通过振动频率与结构关系的研究揭示其内在联系及规律性。对两条途径的亲电诱导效应进行了讨论, 并提出一个能定性标志Fe→Mo电荷迁移大小的有用参数Δν值。     

Cyclization of electron-deficient cyclopentadienone with 2-alkenyl and 2-alkynylamines via sequential pericyclic reaction pathway.

The pericyclic reactions of 2,5-bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone (1a) with both allylic and propargylic amines have been investigated. The reaction proceeded via initial formation of the 1,4 adducts followed by the ene cyclization and/or sequential pericyclic reactions depending upon the structures of the amines. The reaction of 1a with diallylamine (2a) gave the tetracyclic compound (3a). On the other hand, the reaction of 1a with 2-propynylamine (2c) gave exclusively the bicyclic compound (5c). In the reactions with the secondary 2-propynylamines (2d,e), the tetracyclic compounds (3d,e) were exclusively formed. The reactions of 1a with alpha-branched primary 1,1-dialkyl-2-propynylamines (2f,g) gave mixtures of 3- and 5-type compounds. The tetracyclic compounds 3 were formed from the intramolecular [4+2]pi cycloadditions of the [1,5]-sigmatropic rearrangement products of the 1,4 adducts of 1a and 2, followed by the [1,5]-sigmatropic rearrangement of hydrogen and dehydrogenation. The bicyclic compounds 5 were derived from the [2pi+2pi+2sigma] reaction of the 1,4 adducts of 1a and 2. The one-pot multistage sequential pericyclic reactions were discussed on the basis of the X-ray crystallographic structures and the MO calculation data.     

Versatile binding properties of a di-2-pyridyl ketone nicotinoylhydrazone ligand: crystal structure of a Cu(II) complex

Six new copper complexes of di-2-pyridyl ketone nicotinoylhydrazone (HDKN) have been synthesized. The complexes have been characterized by a variety of spectroscopic techniques and the structure of [Cu(DKN)(2)]·H(2)O has been determined by single crystal X-ray diffraction. The compound [Cu(DKN)(2)]·H(2)O crystallized in the monoclinic space group P2(1) and has a distorted octahedral geometry. The IR spectra revealed the presence of variable modes of chelation for the investigated ligand. The EPR spectra of compounds [Cu(2)(DKN)(2)(μ-N(3))(2)] and [Cu(2)(DKN)(2)(μ-NCS)(2)] in polycrystalline state suggest a dimeric structure as they exhibited a half field signal, which indicate the presence of a weak interaction between two Cu(II) ions in these complexes.     

Evidence from ESR studies for [Co(eta-C2H4)3] produced at 77 K in a rotating cryostat

Co atoms were reacted with ethene at 77 K and the paramagnetic products studied by electron spin resonance (ESR) at X- and K-bands. The ESR spectra of the major product at both frequencies showed eight cobalt multiplets (ICo=7/2) indicating a mono-cobalt complex. The spectra have orthorhombic g and cobalt hyperfine tensors and were simulated by the parameters; g1=2.284, g2=2.0027, g3=2.1527; A1<-25 MHz, A2=-109 MHz, A3=-198 MHz. Proton and 13C (1% natural abundance) hyperfine couplings were lower than the line widths (<2 MHz) indicating less than 0.5 spin transfer to the ethene ligands. We assigned the spectrum to a Jahn-Teller-distorted planar trigonal mono-cobalt tris-ethene [Co(eta-C2H4)3] complex in C2v symmetry. The SOMO is either a 3dx2-y2 (2a1) orbital in a T-geometry or a 3dxy (b1) orbital in a Y-geometry but there is only a spin density, a2, of 0.30 in these d orbitals. The spin deficiency of 0.70 is attributed to two factors; spin transfer from the Co to ethene pi/pi* orbitals and a 4p orbital contribution, b2, to the SOMO. Calculations of a2 and b2 have been made at three levels of spin transfer, theta. At theta=0.00a2 is 0.23 and b2 is 0.78, at theta=0.25a2 is 0.25 and b2 is 0.52 and at theta=0.50a2 is 0.28 and b2 is 0.23. The other possible assignment to a mono-cobalt bis-ethene complex [Co(eta-C2H4)2] cannot be discounted from the ESR data alone but is considered unlikely on other grounds. The complex is stable up to approximately 220 K indicating a barrier to decomposition of approximately 50 kJ Mol-1     

On the strongly correlated electron hydride Ce2Ni2MgH7.7

The intermediate valence compound Ce 2Ni 2Mg absorbs irreversibly hydrogen when exposed under 1 MPa of H 2 pressure at room temperature. The resulting hydride Ce 2Ni 2MgH 7.7 is stable in air and crystallizes as the deuteride La 2Ni 2MgD 8 in a monoclinic structure (space group P2 1 /c) with the unit cell parameters a = 11.7620(2), b = 7.7687(2), and c = 11.8969(2) A and beta = 92.75 degrees . The H-insertion in Ce 2Ni 2Mg induces a structural transition from a tetragonal to a monoclinic symmetry with an unit cell volume expansion Delta V m/ V m approximately 24.9%. The investigation of the hydride by magnetization, electrical resistivity, and specific heat measurements indicates a change from an intermediate valence behavior to a non-magnetic strongly correlated electron system. This transition results from a change of the coupling constant J cf between 4f(Ce) and conduction electrons induced by the hydrogenation.     

Role of the phosphine ligands on the stabilization of monoadducts of the model nucleobases 1-methylcytosine and 9-methylguanine in platinum(II) complexes

The addition of 1-methylcytosine (1-MeCy) or 9-methylguanine (9-MeGu) to solutions of cis-(PPh3)2P(ONO2)2 (1a), in a molar ratio of 1:1, affords the monoadducts cis-[(PPh3)2Pt(1-MeCy)(ONO2)]NO3 (2a) and cis-[(PPh3)2Pt(9-MeGu)(ONO2)]NO3 (3a) and only trace amounts of the bisadducts cis-[(PPh3)2Pt(1-MeCy)2](NO3)2 (4a) and cis-[(PPh3)2Pt(9-MeGu)2](NO3)2 (5a), respectively. The X-ray structural determination of 2a and 3a indicates a strong pi-pi stacking interaction between one of the PPh3 phenyl groups and the pyrimydinic N3-platinated cytosine or the imidazole part of the N7-coordinated guanine base. The addition of a further equiv of nucleobase to the monoadducts forms quantitatively the bisadducts that have been isolated as pure compounds 4a and 5a. Under the same experimental conditions, the dinitrato analogue cis-[(PMePh2)2Pt(ONO2)2] (1b) forms the monoadducts 2b and 3b in equilibrium with a relatively high concentration (20-30%) of the bisadducts cis-[(PMePh2)2Pt(1-MeCy)2](NO3)2 (4b) and cis-[(PMePh2)2Pt(9-MeGu)2](NO3)2 (5b), which have been structurally characterized by single-crystal X-ray analysis. The characterization of the isolated complexes by multinuclear NMR spectroscopy is also described.     

全氟卤代烷在氯磺酸中的电化学反应

本文报道了以氯磺酸钾为电解质, 铂为电极, 进行氯磺酸的阳极氧化, 产生过氧二磺酰氯, 并和阳极池内α,ω-氯磺含氟烷进行反应, 生成相应的氯磺酸酯, 反应主要副产物为α,ω-二氯全氟烷, 在阳极有大量氢气逸出, 并得到碘。     

Interaction of diatomic germanium with lithium atoms: electronic structure and stability

Quantum chemical calculations were applied to investigate the electronic structure of mono-, di-, and trilithiated digermanium (Ge2Lin) and their cations (n=0-3). Computations using a multiconfigurational quasidegenerate perturbation approach based on complete active space self-consistent-field wave functions, and density functional theory reveal that Ge2Li has a 2B1 ground state with a doublet-quartet energy gap of 33 kcal/mol. Ge2Li2 has a singlet ground state with a 3Au-1A1 gap of 29 kcal/mol, and Ge2Li3 a doublet ground state with a 4B2-2A2 separation of 22 kcal/mol. The cation Ge2Li+ has a 3B1 ground state, being 13 kcal/mol below the open-shell 1B1 state. The computed electron affinities for diatomic germanium are EA(1)=1.9 eV, EA(2)=-2.5 eV, and EA(3)=-6.0 eV, for Ge2-, Ge2 (2-), and Ge2 (3-), respectively, indicating that only the monoanion is stable with respect to electron detachment, in such a way that Ge2Li is composed by Ge2-Li+ ions. An "atoms-in-molecules" analysis shows the absence of a ring critical point in Ge(2)Li. An electron localization function analysis on Ge2Li supports the view that the Ge-Li bond is predominantly ionic; however, a small covalent character could be anticipated from the analysis of the Laplacian at the Ge-Li bond critical point. The ionic picture of the Ge-Li bond is further supported by a natural-bond-order analysis and the Laplacian of the electron density. The calculated Li affinity value for Ge2 is 2.08 eV, while the Li+ cation affinity value for Ge2- is 5.7 eV. The larger Li+ cation affinity value of Ge2- suggests a Ge2-Li+ interaction and thus supports the ionic nature of Ge-Li bond. In GeLi4 and Ge2Li, the presence of trisynaptic basins indicates a three-center bond connecting the germanium and lithium atoms.