Spectroscopic Studies on Co(Ⅱ),Ni(Ⅱ),Zn(Ⅱ) Complexes with 4,4'-Bipyridine

Fourier-transform infrared(FTIR),Raman and ultraviolet-visible spectra of 4,4'-bipyridine and its me-tal-organic coordination compounds synthesized from 4,4'-bipyridine and nitrate of Co(Ⅱ),Ni(Ⅱ) and Zn(Ⅱ) were measured and analyzed,respectively.The main FTIR and Raman bands were assigned in detail.The relationship between these characteristic bands and the structure of ligands and coordination compounds were discussed.     

STUDIES ON REDOX PROPERTIES OF HETEROPOLY ACIDS (SALTS) AND THEIR DERIVATIVES WITH KEGGIN AND DAWSON STRUCTURES

We have systematically studied redox properties of two series of several dozen heteropoly acids (salts) and their derivatives with vanadium and rare-earth elements with Keggin and Dawson structures, e. g. LnHSiMo_(12), SiMo_(12-n)V_n, M_(1.5)PMo_(12), PMo_(12-n)V_n, PW_(12-n_V_n, Ln(PMo_(11))_2, Sm(XMo_(11))_2 and P_2Mo_(18-n)V_n, etc., and obtained their sequence of oxidation. It was found that there is a linear relationship between the reduction potentials of heteropoly anions and the derivatives of heteropoly anions with rare-earth elements with Keggin structure and nq~2 (n and q are the principal quantum number and charge of the central ion respectively). On the basis of the electrostatic model the regularity of oxidation and reduction was rationalized.     

Theoretical Investigation on the Luminescent Properties of Polyfluorene and Poly（fluorene-co-thiophene）

The density functional theory was employed to study the structures, ionization potentials(IPs), electron affinities(EAs), and HOMO-LUMO gaps(ΔH-L) of the oligomers. The time-dependent density functional theory(TD-DFT) and ZINDO were employed to study the lowest excitation energies(Egs) and the absorption and emission spectra of the oligomers of polyfluorene(PF) and poly(fluorene-co-thiophene)(PFT). By extrapolating ΔH-L and Egs to those of infinite chain length, band gaps and effective conjugation lengths o...     

SYNTHESIS AND CARACTERIZATION OF TERNARY COMPLEXES CONTAINING Cu(II),L-HISTIDINE AND NUCLEOTIDE

The ternary complexes containing Cu(II),L-His and nucleotide(5'-GMP and 5'-IMP)were synthesized and characterized.IR and ~1H NMRspectra show that Cu(II)binds to carboxylate oxygen and imidazolenitrogen of L-His and purine N_7 of 5'-GMP and 5'-IMP.The interactionof Cu(II)with Po_3~(2-)of 5'-GMP is present,but that for 5'-IMP is notpresent.     

New Metabolites of Aconitine in Rabbit Urine

A sensitive analytical method to identify and determine aconitine and its metabolites in rabbit urine was developed by liquid chromatography-electrospray ionization mass spectrometry (LC/ESI-MS^n). In this method,aconitine and its four metabolites in rabbit urine were isolated and deduced as 16-O-demethylaconine (M1), benzoylaconine (M2),16-O-demethylbenzoylaconine (M3) and aconine(M4).M1 and M3 are new metabolites of aconitine and M2 and M4 are first identified in rabbit urine.     

Syntheses,Crystal Structures and Fluorescence Properties of Two Complexes Based on a New Chiral Ligand

A new homochiral ligand,(R)-2-(4-pyridyl)-4,5-dihydrothiazole-4-carboxylic acid(HL~R), has been synthesized. Two complexes, [ZnL_2~R(H_2O)_2]?H_2O(1) and [MnL_2~R(H_2O)_2]?H_2O(2) have been prepared by the reactions of Zn(Ⅱ) and Mn(Ⅱ) ions with the ligand HLR, and characterized by single-crystal X-ray diffraction analysis and fluorescence. Complexes 1 and 2 are isomorphs, and both of the Zn(Ⅱ) and Mn(Ⅱ) centers in 1 and 2 are six-coordinated by the two NO units of two ligands and two water oxygen atoms, showing distorted octahedral coordination geometry. Complexes 1 and 2 show fluorescent properties in the solid state at room temperature.     

Manganese Oxide(MnO) and Cadmium Dioxide(CdO_2) Attached to Carbon Nanotube(8, 0) as Anodes of Metal-ion Batteries: a DFT Study

Performance of carbon nanotube(CNT) and their attached metal oxides(manganese oxide(MnO) and cadmium dioxide(CdO2)) structures as anode electrodes in lithium-ion battery(LIB) and potassium-ion battery(KIB) are investigated. The Gibbs free energy of adsorption of Li and K atoms/ions on surfaces of CNT(8, 0), CNT(8, 0)-MnO and CNT(8, 0)-CdO2 are calculated. The cell voltages(Vcell) of Li and K atoms/ions adsorption on studied surfaces are examined. The Vcell of LIBs with metal-oxides attached to CNT(8, 0) as anode electrodes are higher than those KIBs. The adsorbed metal oxides(MnO and CdO2) on CNT(8, 0) increased the charges, electronic conductivity and Vcell of LIB and KIB, efficiently. The CNT(8, 0)-CdO2 as anode electrodes in LIB and KIB is proposed.     

In-situ reduction synthesis of manganese dioxide@polypyrrole core/shell nanomaterial for highly efficient enrichment of U(Ⅵ) and Eu(Ⅲ)

Radionuclides with long half-life are toxic,and thereby result in serious threat to human beings and ecological balance.Herein,a simple two-step synthesis method was used to prepare manganese dioxide@polypyrrole(Mn O_2@PPy)core/shell structures for efficient removal of U(Ⅵ)and Eu(Ⅲ)from aqueous solutions.The adsorption of U(Ⅵ)and Eu(Ⅲ)were investigated under different kinds of experimental conditions.The experimental results suggested that the adsorption of U(Ⅵ)and Eu(Ⅲ)on Mn O_2@PPy were greatly affected by p H.U(Ⅵ)adsorption on Mn O_2@PPy was independent of ionic strength at p H6.0,and dependent on ionic strength at p H6.0.However,Eu(Ⅲ)adsorption on Mn O_2@PPy was independent of ionic strength at the whole p H range of experimental conditions.The maximum adsorption capacities(q_(max))of U(Ⅵ)and Eu(Ⅲ)were 63.04 and54.74 mg g~(-1)at T=298 K,respectively.The BET,XRD,FTIR and XPS analysis evidenced that high adsorption capacities of U(Ⅵ)and Eu(Ⅲ)on Mn O_2@PPy were mainly due to high surface area and rich metal oxygen-containing group(i.e.,Mn–OH and Mn–O),and the interaction was mainly attributed to strong surface complexation and electrostatic interaction.This study highlighted the excellent adsorption performance of U(Ⅵ)and Eu(Ⅲ)on Mn O_2@PPy and could provide the reference for the elimination of radionuclides in real wastewater management.     

Effects of Doping and Oxygen Vacancy Concentrations on Oxygen Ion Migration in Sm_xCe_(1-x)O_(2-δ): a DFT + U Study

Influence of doping and oxygen vacancy concentrations on oxygen ion or oxygen vacancy(V) migration energies of Sm_xCe_(1-x)O_(2-δ)(x = 0.0625, 0.125, 0.25 and δ = 0.0625, 0.125) systems using a GGA+U method are studied. Calculated results show that advantage migration types change from V?O~(2-) to O~(2-) ?V as x and δ increase. For V?O~(2-) migrations of the Sm_(0.0625)Ce_(0.9375)O_(1.9375) and Sm_(0.125)Ce_(0.875)O_(1.9375) systems, electrostatic attractions between Sm~(3+) and V, defect associations between Ce~(3+) and V, and steric hindrances of Sm~(3+) affect the migration energies. For O~(2-) ?V migrations of the Sm+(0.125)Ce_(0.875)O_(1.875) and Sm_(0.25)Ce_(0.75)O_(1.875) systems, migration energies of O~(~(2-) ) are affected by electrostatic repulsions between Sm~(3+) and O~(2-) and defect associations between Ce~(3+) and V. Increases of the oxygen vacancy and Sm~(3+) doping concentrations benefit the oxygen ion and vacancy migrations, respectively.     

Application of 4,4＇-（2-Carboxypropane-1,3-diyl）dibenzoic Acid in Coordination Metal Complexes： Synthesis,Characterization, and Theoretical Studies①

[Pb(HL)(phen)]n(1) and [Cd3L2(phen)]n(2), where phen = 1,10-phenanthroline and L = 4,4'-(2-carboxylatopropane-1,3-diyl)dibenzoate, were hydrothermally prepared and fully characterized by X-ray single-crystal diffraction, infrared spectroscopy and thermogravimetric analyses. The decomposition temperature of 1 and 2 was measured to be ca. 304 and 416 ℃, respectively. The charge transfer transition based absorption of 1 and 2 was also verified by the powder scattering spectra and theoretical analyses.     

Crystal engineering of a versatile building block toward the design of novel inorganic-organic coordination architectures

Six novel inorganic-organic coordination supramolecular networks based on a versatile linking unit 4-pyridylthioacetate (pyta) and inorganic Co(II), Cu(II), Ag(I), Zn(II), Mn(II) and Pb(II) salts have been prepared in water medium and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of CoCl(2).6H(2)O with Hpyta afforded a neutral mononuclear complex [Co(pyta)(2)(H(2)O)(4)](1), which exhibits a two-dimensional (2-D) layered architecture through intermolecular O-HO interactions. Reaction of CuCl(2.2H(2)O with Hpyta yielded a neutral one-dimensional (1-D) coordination polymer [[Cu(pyta)(2)(H(2)O].0.5H(2)O](n)(2) consisting of rectangle molecular square units, which show a three-dimensional (3-D) supramolecular network through S...S and O-H...O weak interactions. However, when AgNO(3), Zn(OAc)(2).2H(2)O or MnCl(2).4H(2)O salts were used in the above self-assembled processes, the neutral 2-D coordination polymers [Ag(pyta)](n)(3), [[Zn(pyta)(2)].4H(2)O](n)(4) or [[Mn(pyta)(2)(H(2)O)]](n)(5) with different topologies were obtained, respectively. While substituting the transition metal ions used in 1-5 with Pb(OAc)(2).3H(2)O, a one-dimensional coordination polymer [Pb(pyta)(2)](n)(6), which shows a novel 2-fold interpenetrating 2-D supramolecular architecture through weak SS interactions, was isolated. It is interesting to note that the building block pyta anion exhibits different configurations and coordination modes in the solid structures of complexes 1-6. These results indicate that the versatile nature of this flexible ligand, together with the coordination preferences of the metal centers, play a critical role in construction of these novel coordination polymers or supramolecules. The spectral and thermal properties of these new materials have also been investigated.     

A new Zn(II) coordination polymer with 4-pyridylthioacetate: assemblies of homo-chiral helices with sulfide sites

A coordination polymer [Zn(pyta)(OH)] (pyta = 4-pyridylthioacetate), was synthesized and structurally characterized; it is constructed by an alternating assembly of two types of homo-chiral helices, [Zn-OH] and [Zn-pyta], in which the sulfide moieties are fastened in the latter columns.     

基于2,4,6-吡啶三羧酸配体桥连的铁(Ⅱ)/镍(Ⅱ)配位聚合物的水热合成及结构表征

在水热反应条件下FeCl₂·6H₂O、2,4,6-吡啶三羧酸(H₃pyta)和NaOH反应合成了1种一维链状铁配位聚合物[Fe₃(pyta)₂(H₂O)₈] (1);同样条件下Ni(OAc)₂·4H₂O、2,4,6-吡啶三羧酸(H₃pyta)、NaOH和4-氨基-3,5-二(4-吡啶基)-1,2,4-三氮唑(abpt)反应合成了1种二维网状镍配合物[Ni₃(pyta)₂(abpt)₂(H₂O)₃]·2H₂O (2)。通过元素分析和红外光谱对这2个配位聚合物进行了表征。单晶结构表明：配合物1的晶体属于单斜晶系,Cc空间群;配合物2的晶体属于单斜晶系,P2₁/c空间群。在配合物1中,pyta^3-配体采取μ₂-和μ₄-pyta^3- 2种桥连模式将Fe原子连成了沿c轴方向延伸的Fe-pyta链。而在配合物2中,pyta^3-配体仅采取μ₂-桥连模式将Ni原子连成线型三核[Ni₃(pyta)₂]单元,这些三核单元进一步通过abpt辅助配体桥连成二维 (4,4)层状结构。     

Influence of the Side‐Chain Length on the Cellular Uptake and the Cytotoxicity of Rhenium Triscarbonyl Derivatives: A Bimodal Infrared and Luminescence Quantitative Study

Rhenium triscarbonyl complexes fac‐[Re(CO)₃(N^N)] with appropriate ancillary N^N ligands are relevant for fluorescent bio‐imaging. Recently, we have shown that [Re(CO)₃] cores can also be efficiently mapped inside cells using their IR signature and that they can thus be used in a bimodal approach. To describe them we have coined the term SCoMPIs for single‐core multimodal probes for imaging. In the context of the use of these SCoMPIs in bio‐imaging, the questions of their cellular uptake and cytotoxicity are critical. We report here a series of compounds derived from the [Re(CO)₃Cl(pyta)] core (pyta=4‐(2‐pyridyl)‐1,2,3‐triazole). The pyta ligand is of interest because it can be easily functionalized. Aliphatic side chains (C₄, C₈, and C₁₂) were appended to this core. A correlative study involving IR and luminescence was performed to monitor and quantify their cellular internalization. We studied the relationship between lipophilicity (log P(o/w)), cytotoxicity (IC₅₀), and cellular uptake, and we showed that both uptake and cytotoxicity increase with the length of the side chain, with a higher uptake for the C₁₂ derivative. This study stresses the distinction that has to be made between apparent toxicity, determined as an incubation concentration IC₅₀, and intrinsic toxicity. Indeed, the intrinsic toxicity of a compound can remain hidden if it is not cell permeable. Therefore it must be kept in mind that IC₅₀ values are composite values, reflecting both cellular uptake and intrinsic toxicity.     

Preparation of Zinc (II) and cadmium (II) complexes of the tetradentate Schiff base ligand 2-((E)-(2-(2-(pyridine-2-yl)- ethylthio)ethylimino)methyl)-4-bromophenol (PytBrsalH)

We describe the synthesis and characterization of two new zinc (II) and cadmium (II) complexes of the tetradentate dissymmetric Schiff base ligand 2-((E)-(2-(2-(pyridine-2-yl)ethylthio)ethylimino)methyl)-4-bromophenol (PytBrsalH), prepared from 1-(2-pyridyl)-3-thia-5-aminopentane (pyta) and 5-bromosalicylaldehyde. The complexes were synthesized by treating an ethanolic solution of the ligand with equimolar amounts of appropriate metal salts in 1 M methanolic solution of NaOH or alternatively, by a more direct route in which the two reactants are added to a solution of the ligand immediately after formation of the latter and prior to any isolation. The complexes were characterized by elemental analysis, FTIR, (1)H-NMR, electronic spectra and molar conductivity. According to obtained data, the probable coordination geometries of zinc and cadmium in these complexes with mixed N, S and O donor atoms are tetrahedral- and octahedral-like,respectively. Both complexes were found to be 1:1 electrolyte systems in acetonitrile.     

Two New Iron Coordination Polymers Based on Fe-pyta ChainsIncorporating Pyridine-2,4,6-tricarboxylate

Reaction of FeCIz＇6H20, pyridine-2,4,6-tricarboxylic acid（H3pyta） and NaOH in the hydrothermal system at 185 ℃ resulted in the formation of 1D coordination polymer[Fe（Hpyta）（H2O）2]（1） based on Fe-Hpyta chains. When the abpt[abpt=-4-amino-3,5-bis（4-pyridyl）-l,2,4-triazole] ligand was employed in the reaction system, a 3D supramolecular porous network （H2bpt）[Fe（pyta）（H2O）2]·4H2O（2） was obtained. The framework was constructed with negative （Fe-pyta） chains and the positive H3bpt^＋ in situ, formed from the abpt reagent, to form 1D channels filled with guest water molecules via hydrogen-bonds. X-Ray diffraction crystal structure analysis shows that complex 1 crystallized in the monoclinic system, space group C2/c, a=1.1490（5） nm, b=0.9008（4） nm, c=1.0058（5） nm, B=107.254（9）°, V=0.9942（8） nm3, Z=4; and complex 2 crystallizes in the triclinic system, space group P1 with a=0.90392（11） nm, b=0.96027（11 ） nm, c=1.55540（18） nm, a=73.558（2）°,B= 86.126（2）°,r= 68.745（2）°, V=1.2059（2） nm^3 and Z=2.     

Solid state NMR characterization of individual compounds and solid solutions formed in Sc(2)O(3)--V(2)O(5)--Nb(2)O(5)--Ta(2)O(5) system

In this study, (51)V, (45)Sc and (93)Nb MAS NMR combined with satellite transition spectroscopy analysis were used to characterize the complex solid mixtures: VNb(9(1-x))Ta(9x)O(25), ScNb((1-x))Ta(x)O(4) and ScNb(2(1-x))Ta(2x)VO(9) (x = 0, 0.3, 0.5, 0.7, 1.0). This led us to describe the structures of Sc and V sites. The conclusions were based on accurate values for (51)V quadrupole coupling and chemical shift tensors obtained with (51)V MAS NMR/SATRAS for VNb(9)O(25), VTa(9)O(25) and ScVO(4). The (45)Sc NMR parameters have been obtained for Sc(2)O(3), ScVO(4), ScNbO(4) and ScTaO(4). On the basis of (45)Sc NMR and data available from literature, the ranges of the (45)Sc chemical shift have been established for ScO(6) and ScO(8). The gradual change of the (45)Sc and (51)V NMR parameters with x confirms the formation of solid solutions in the process of synthesis of VNb(9(1-x))Ta(9x)O(25) and ScNb((1-x))Ta(x)O(4), in contrast to ScNb(2(1-x))Ta(2x)VO(9). The cation sublattice of ScNb((1-x))Ta(x)O(4) is found to be in octahedral coordination. The V sites in VNb(9(1-x))Ta(9x)O(25) are present in the form of slightly distorted tetrahedra. The (93)Nb NMR parameters have been obtained for VNb(9)O(25).     

Molecular nitrides containing group 4 and 5 metals: single and double azatitanocubanes

Treatment of [[Ti(eta(5)-C(5)Me(5))(micro-NH)](3)(micro(3)-N)] (1) with the imido complexes [Ti(NAr)Cl(2)(py)(3)] (Ar=2,4,6-C(6)H(2)Me(3)) and [Ti(NtBu)Cl(2)(py)(3)] in toluene affords the single azatitanocubanes [[Cl(2)(ArN)Ti]( micro(3)-NH)(3)[Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)]].(C(7)H(8)) (2.C(7)H(8)) and [[Cl(2)Ti](micro(3)-N)(2)(micro(3)-NH)[Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)]] (3), respectively. Similar reactions of complex 1 with the niobium and tantalum imido derivatives [[M(NtBu)(NHtBu)Cl(2)(NH(2)tBu)](2)] (M=Nb, Ta) in toluene give the single azaheterometallocubanes [[Cl(2)(tBuN)M](micro(3)-N)(micro(3)-NH)(2)[Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)]] (M=Nb (4), Ta (5)), both complexes react with 2,4,6-trimethylaniline to yield the analogous species [[Cl(2)(ArN)M](micro(3)-N)(micro(3)-NH)(2)[Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)]].(C(7)H(8)) (Ar=2,4,6-C(6)H(2)Me(3), M=Nb (6.C(7)H(8)), Ta (7.C(7)H(8))). Also the azaheterodicubanes [M[micro(3)-N)(2)(micro(3)-NH)](2)[Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)](2)].2C(7)H(8) [M=Ti (8.2C(7)H(8)), Zr (9.2C(7)H(8))], and [M[(micro(3)-N)(5)(micro(3)-NH)][Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)](2)].2 C(7)H(8) (Nb (10.2C(7)H(8)), Ta (11.2C(7)H(8))) were prepared from 1 and the homoleptic dimethylamido complex [M(NMe(2))(x)] (x=4, M=Ti, Zr; x=5, M=Nb, Ta) in toluene at 150 degrees C. X-ray crystal structure determinations were performed for 6 and 10, which revealed a cube- and double-cube-type core, respectively. For complexes 2 and 4-7 we observed and studied by DNMR a rotation or trigonal-twist of the organometallic ligands [[Ti(eta(5)-C(5)Me(5))(micro-NH)](3)(micro(3)-N)] (1) and [(micro(3)-N)(micro(3)-NH)(2)[Ti(3)(eta(5)-C(5)Me(5))(3)(micro(3)-N)]](1-). Density functional theory calculations were carried out on model complexes of 2, 3, and 8 to establish and understand their structures.     

Spectroelectrochemical studies on mixed-valence states in a cyanide-bridged molecular square, [Ru(II)(2)Fe(II)(2)(mu-CN)(4)(bpy)(8)](PF6)(4).CHCl(3).H(2)O

A cyanide-bridged molecular square of [Ru(II) (2)Fe(II) (2)(mu-CN)(4)(bpy)(8)](PF(6))(4).CHCl(3).H(2)O, abbreviated as [Ru(II) (2)Fe(II) (2)](PF(6))(4), has been synthesised and electrochemically generated mixed-valence states have been studied by spectroelectrochemical methods. The complex cation of [Ru(II) (2)Fe(II) (2)](4+) is nearly a square and is composed of alternate Ru(II) and Fe(II) ions bridged by four cyanide ions. The cyclic voltammogram (CV) of [Ru(II) (2)Fe(II) (2)](PF(6))(4) in acetonitrile showed four quasireversible waves at 0.69, 0.94, 1.42 and 1.70 V (vs. SSCE), which correspond to the four one-electron redox processes of [Ru(II) (2)Fe(II) (2)](4+) right arrow over left arrow [Ru(II) (2)Fe(II)Fe(III)] (5+) right arrow over left arrow [Ru(II) (2)Fe(III) (2)](6+) right arrow over left arrow [Ru(II)Ru(III)Fe(III) (2)](7+) right arrow over left arrow [Ru(III) (2)Fe(III) (2)](8+). Electrochemically generated [Ru(II) (2)Fe(II)Fe(III)](5+) and [Ru(II) (2)Fe(III) (2)](6+) showed new absorption bands at 2350 nm (epsilon =5500 M(-1) cm(-1)) and 1560 nm (epsilon =10 500 M(-1) cm(-1)), respectively, which were assigned to the intramolecular IT (intervalence transfer) bands from Fe(II) to Fe(III) and from Ru(II) to Fe(III) ions, respectively. The electronic interaction matrix elements (H(AB)) and the degrees of electronic delocalisation (alpha(2)) were estimated to be 1090 cm(-1) and 0.065 for the [Ru(II) (2)Fe(II)Fe(III) (2)](5+) state and 1990 cm(-1) and 0.065 for the [Ru(II) (2)Fe(III) (2)](6+) states.     

Formation of two isomeric closo-[(eta5-C5H5)FePC2B8H10] phosphadicarbaborane analogues of ferrocene via isolable eta1-bonded complexes of the [7-[(eta5-C5H5)Fe(CO)2]-(eta1-nido-PC2B8H10)] type

The reaction of nido-[7,8,9-PC(2)B(8)H(11)] (1) with [[CpFe(CO)(2)](2)] (Cp=eta(5)-C(5)H(5) (-)) in benzene (reflux, 3 days) gave an eta(1)-bonded complex [7-Fp-(eta(1)-nido-7,8,9,-PC(2)B(8)H(10))] (2; Fp=CpFe(CO)(2); yield 38 %). A similar reaction at elevated temperatures (xylene, reflux 24 h) gave the isomeric complex [7-Fp-(eta(1)-nido-7,9,10-PC(2)B(8)H(10))] (3; yield 28 %) together with the fully sandwiched complexes [1-Cp-closo-1,2,4,5-FePC(2)B(8)H(10)] 4 a (yield 30%) and [1-Cp-closo-1,2,4,8-FePC(2)B(8)H(10)] 4 b (yield 5%). Compounds 2 and 3 are isolable intermediates along the full eta(5)-complexation pathway of the phosphadicarbaborane cage; their heating (xylene, reflux, 24 h) leads finally to the isolation of compounds 4 a (yields 46 and 52%, respectively) and 4 b (yields 4 and 5%, respectively). Moreover, compound 3 is isolated as a side product from the heating of 2 (yield 10%). The structure of compound 4 a was determined by an X-ray structural analysis and the constitution of all compounds is consistent with the results of mass spectrometry and IR spectroscopy. Multinuclear ((1)H, (11)B, (31)P, and (13)C), two-dimensional [(11)B-(11)B]-COSY, and (1)H[(11)B(selective)] magnetic resonance measurements led to complete assignments of all resonances and are in excellent agreement with the structures proposed.