Air-stable Compounds Research Articles

A New Polymorph of the Heteronuclear Cluster Ru4Pt2(CO)18

By reacting Ru(CO)5 with the stoichiometric amount of Pt(C7H10)3(C7H10=bicyclo[2.2.1]heptene) in heptane and by removing the excess of CO, two polymorphs of Ru4Pt2(CO)18, 1, were isolated and characterized by X-ray diffraction, namely the already known monoclinic (α) and a new orthorhombic (β) phase. Crystal data of the β phase: space group Pna21; a=17.738(3), b=15.596(2), c=10.357(1), V=2865 A3. IR spectra (Nujol mulls) of the two polymorphs are significantly different, while no difference was noticed in solution. The air-stable compounds quickly decompose in a carbon monoxide atmosphere giving Ru3CO12 and the unstable [Pt(CO)]n, n≤2.

Synthesis, spectroscopic characterization, and structural systematics of new triorganophosphinecopper(I) poly(pyrazol-1-yl)borate complexes †

Mono- and bis-(trialkyl- and triaryl-phosphine)copper(I) derivatives containing anionic bis-, tris- and tetrakis-(pyrazol-1-yl)borates were prepared from CuCl, [CuBr(Me2S)] or [Cu(C6H6)0.5(O3SCF3)]2, R3P (R = phenyl, benzyl, cyclohexyl, o-, m-, or p-tolyl) or R′Ph2P (R′ = methyl or ethyl), and M[HnB(pz)4-n] (M = Na or K, n = 0, 1 or 2; Hpz = pyrazole in general; in detail, pyrazole (Hpz), 3,5-dimethylpyrazole (Hm2pz), 3-methylpyrazole (Hmpz)) and characterized through analytical and spectral measurements (IR, 1H and 31P NMR). The same complexes can be obtained also from the reaction of [Cu(O2NO)(PR3)2] with M[HnB(pz)4-n]. These air-stable compounds are non-electrolytes in CH2Cl2 and in acetone, in which they slowly decompose even with the strict exclusion of oxygen. Low-temperature single crystal structural characterizations were undertaken for several of them. The structurally authenticated arrays fall into three different types: (a) [Cu((pz)2BHn(pz)2-n)(PR3)2] with a four-co-ordinate P2Cu(N2) co-ordination sphere, (b) [Cu((pz)3BH)(PR3)] with a four-co-ordinate PCu(N3) co-ordination sphere, (c) [Cu((pz)2BHn(pz)2-n)(PR3)] with a three-co-ordinate PCu(N2) co-ordination sphere.

Synthesis, structure and electronic properties of the cerium and potassium thiosilicate: KCeSiS4

Abstract The cerium and potassium thiosilicate KCeSiS 4 has been synthesized at 800 °C from Ce, Si, K 2 S and S precursors weighted in the K:Ce:Si:S = 1:1:1.15:4.3 ratio. This yellow, air stable compound crystallizes in the monoclinic space group P2 1 , (No. 4) with the cell parameters: a = 6.5201(3) A, b = 6.5982(3) A, c = 8.6920(5) A, β = 107.701(3) °, V = 356.23(3) A 3 and Z = 2. Refinement of 36 parameters by the Rietveld method, using 974 reflections led to R p (%) = 2.49, R wp (%) = 3.35 and χ 2 = 2.71. KCeSiS 4 , isostructural to KLnMQ 4 (Ln = La, Nd, Gd, Y; M = Si, Ge; Q= S, Se), consists of two-dimensional ∞ 2 [CeSiS 4 ] − anionic layers separated by K + ions. These layers are built upon [CeS 7 ] distorted monocapped trigonal prisms, sharing 2 edges and 2 corners with each other, and upon [SiS 4 ] tetrahedra linked to the ∞ 2 [CeS 4 ] 5− skeleton by edge and face sharing. From magnetic measurements, an effective magnetic moment μ eff (300 K) = 2.73(2) μ B was calculated in good agreement with the k (i) Ce (III) Si (IV) S 4 (−II) charge balance. From diffuse reflectance measurements, a band gap of 2.68(1) eV correlated to the occurrence of a 4 f → 5 d electronic transition was evidenced. Moreover, chromatic L/a/b coefficients, equal respectively to 88.37/−18.85/52.91, have been determined for the bright yellow colour of the compound. These parameters compare rather well with those of NiTiO 3 , a well known industrial pigment. The room temperature strong green luminescence at E = 2.45 eV( λ = 506.1 nm) of KCeSiS 4 has been investigated through emission and excitation spectroscopy in the UV-visible range.

Tetraferrocenyl[5]cumulene, (Fc)2CCCCCC(Fc)2: Synthesis, Electrochemistry, and Reactivity, Including Nickel(0)-Promoted [3]Ferrocenophane Formation and [2+2] Cycloaddition with Fullerene C60

Tetraferrocenyl[5]cumulene (Fc)2CCCCCC(Fc)2 (Fc = ferrocenyl) is synthesized from 1,1-diferrocenyl-1-methoxypropyne by formal dimerization of diferrocenylethenylidenecarbene generated in situ by deprotonation and elimination of methoxide. The cumulene is an air-stable compound of blue color with an electron-rich cumulene moiety, as indicated by various spectroscopic methods. In contrast to other (shorter) ferrocenyl cumulenes which show no reactivity due to steric hindrance, (Fc)2CCCCCC(Fc)2 is a quite reactive compound, as exemplified by (i) transition metal complex formation with Rh(I), (ii) [3]ferrocenophane generation by Ni(0)-promoted intramolecular electrophilic aromatic substitution, and (iii) [2+2] cycloaddition with olefins and alkynes, and (iv) [2+2] cycloaddition with C60 and C70, yielding the first cumulene derivatives of fullerenes. MS, UV−vis, IR, Raman, NMR, cyclic voltammetry, controlled potential coulometry, Mossbauer spectroscopy, and X-ray single-crystal structure analysis have been per...

Silver(I) and gold(I) complexes of hydrotris(3,5-dimethylpyrazol-1-yl)borate: synthesis, spectroscopic and structural characterization, and reactivity toward C-, N- and S-donor ligands.

Reaction of Ag(NO3) with 1 equiv of K[HB(3,5-Me2pz)3] (pzH=pyrazole) and 1 equiv of PR3 (ROPh or C6F5) in methanol provides two new air stable derivatives {[HB(3,5-Me2pz)3]Ag(PR3)}. When the interaction between Ag(O3SCF3), CNR (RBut or cyclohexyl), and K[HB(3,5-Me2pz)3] was carried out in CH2Cl2 at 0°C the air stable neutral compounds {[HB(3,5-Me2pz)3]Ag(CNR)} were obtained. The borderline monodentate imidazole (ImH) reacts with the dinuclear {[HB(3,5-Me2pz)3]Ag}2 yielding the mixed-ligand complex {[HB(3,5-Me2pz)3]Ag(ImH)}. On the other hand when the soft donor 1-methyl-2-mercaptoimidazole (Hmimt) was employed, no stable compound was obtained. We also synthesized [Phen2Ag](O3SCF3) (Phen=1,10-phenanthroline) and its reaction with K[HB(3,5-Me2pz)3] yielded the complex {Phen[HB(3,5-Me2pz)3]Ag}, which is not fluxional in solution. Instead only unmanageable material was obtained from the reaction between (Hmimt)2Ag(O3SCF3) and K[HB(3,5-Me2pz)3]. Finally, the gold(I) complex [HB(3,5-Me2pz)3]Au(PPh3)2 was obtained when the reaction between PPh3AuCl and [HB(3,5-Me2pz)3] was carried out in presence of 1 equiv of PPh3. The solid state structures of {[HB(3,5-Me2pz)3]Ag(PPh2Me)} and {[HB(3,5-Me2pz)3]Ag(P-o-tolyl3)}, show that the silver(I) atoms are in a strongly distorted tetrahedral environment, with the [HB(3,5-Me2pz)3]− donor acting in the tridentate form. The Ag–P and Ag–N bond distances in {[HB(3,5-Me2pz)3]Ag(PPh2Me)} are 2.336(2) Å and 2.316(6), 2.336(5) and 2.329(6) Å, respectively; they are shorter than in the more sterically hindered {[HB(3,5-Me2pz)3]Ag(P-o-tolyl3)} (Ag–P: 2.375(2) Å; Ag–N: 2.361(4) Å). The ligand bite N–Ag–N ranges from 82.1(2)° to 84.8(2)°, whereas the N–Ag–P angle ranges from 125.1(1) to 134.1(1)°.

Structurally Characterized Mesostructured Hybrid Surfactant−Inorganic Lamellar Phases Containing the Adamantane [Ge4S10]4- Anion: Synthesis and Properties

The reaction of aqueous solutions of Na4Ge4S10 with various surfactant alkyltrimethylammonium bromide salts yielded new surfactant−inorganic phases containing the adamantane thiogermanate anion [Ge4S10]4-. The resulting [CnH2n+1N(CH3)3]4Ge4S10 phases with n = 12, 14, 16, and 18 crystallize in the triclinic space group P-1 and contain parallel inorganic planes of unconnected [Ge4S10]4- clusters, separated at mesoscopic scale lengths by organic bilayers of interdigitated cationic surfactant chains. These air-stable compounds were characterized by thermal analyses, Raman, far-IR, and solid-state UV−vis reflectance spectroscopy. Their ability to absorb reversibly various alcohols was studied by in-situ X-ray powder diffraction.

Synthesis and reactivity of the ferrocene-derived phosphine [Fe(η-C5H5){η-C5H4CH2P(CH2OH)2}

The air-stable compound [Fe(η-C5H5){η-C5H4CH2P(CH2OH)2}] 1 has been prepared by the reaction of [Fe(η-C5H5)(η-C5H4CH2NMe3)]I with an excess of P(CH2OH)3. Compound 1 has been used to produce a range of other new compounds, thus demonstrating its versatility as a starting material; the phosphine oxide [Fe(η-C5H5){η-C5H4CH2P(O)(CH2OH)2}] 2, phosphine sulfide [Fe(η-C5H5){η-C5H4CH2P(S)(CH2OH)2}] 3, and other derivatives [Fe(η-C5H5){η-C5H4CH2P(CH2CH2CN)2}] 4, [Fe(η-C5H5){η-C5H4CH2P(CH2NEt2)2}] 5, [Fe(η-C5H5){η-C5H4CH2P(O)(CH2NEt2)2}] 6, [Fe(η-C5H5){η-C5H4CH2P(Me)(CH2OH)2}]I 7 and [Fe(η-C5H5){η-C5H4CH2P(Me)CH2OH}] 8. Crystal structure determinations for 1, 3 and 7 are reported and the hydrogen bonding of each structure described.

Ein ionischer Ti IV-Fulvalenkomplex: [formula omitted

The air-stable compound [[ CpTi( H 2 O)] 2( C 10H 8, O)] 2+( SO 3 CF 3 −) 2 · 1 2 THF is the first example of an ionic titanium-fulvalene complex. It can be prepared from dinuclear ‘titanocene’, trifluoromethanesulphonic acid and small amounts of water. The structure has been confirmed by X-ray crystallography. Space group and lattice constants are: P 1; a = 12.930(3), b = 15.214(3), c = 15.710(8) A ̊ , α = 85.87(2), β = 83.97(2), γ = 72.66(2)°; Z = 4 .

Diphenylborinic acid is a strong inhibitor of serine proteases

Diphenylborinic acid, a commercially available and reasonably air stable compound, was found to be a strong competitive inhibitor of three serine proteases. Compared to phenylboronic acid, it was a thirty-fold better inhibitor of α-chymotrypsin, a fifteen-fold better inhibitor of subtilisin BPN′, and a sixty-fold better inhibitor of bovine trypsin. The pK a and inhibitory ability of methylphenylborinic acid was also determined.

Synthesis and crystal structure of an analogue of the uranyl(VI) ion, containing a linear OUN– group

The crystal structure of the air-stable compound PPh4+[UOCl4{NP(m-Tol)3}]–(m-Tol = C6H4Me-m) shows that it contains a linear (179°) OUN–group, with U–O and U–N distances of 176 and 190 pm respectively, coordinated by four chlorine atoms; the U–O distance is typical of uranyl compounds, and the U–N distance suggests a bond order >2.

PhAs(C5H4)2TiCl2: Das erste Arsen-überbrückte Titanocenophan / PhAs(C5H4)2TiCl2: The First Arsenic-Bridged Titanocenophane

By reacting PhAsCl2 with NaC5H5 in toluene under low temperature conditions PhAs(h1-C5H5)2 was obtained. Metallation of PhAs(h1-C5H5)2 with n-BuLi followed by reaction with TiCl4 led to the As-bridged [1]titanocenophane. The structure and conformation of this air-stable compound are discussed in the light of its 1H NMR spectrum.

Mixed-ligand complexes of technetium Part XI. Nitridotechnetium complexes with tri- and tetradentate azomethines. X-ray molecular and crystal structure of [ N-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-2-aminophenolato](triphenylphosphine)nitridotechnetium(V), TcN(ecbap)(Ph 3P)

Diamagnetic nitridotechnetium(V) complexes with tri- and tetradentate azomethine ligands which possess electron withdrawing groups in their periphery can be prepared starting from TcNCl 2(Ph 3P) 2 or (in the case of the tetradentate ligands) TcNX 4 − (X = Cl, Br). The products are air stable compounds which have been characterized by elemental analysis, infrared and UV-Vis spectroscopy, NMR and mass spectrometry. The mixed-ligand complex [ N-(2-Ethoxycarbonyl-3-oxo-but-l-en(1)yl)-2-aminophen- olato](triphenylphosphine)nitridotechnetium(V) (C 31H 28N 2O 4PTc, M r= 622.5) crystallizes monoclinic in the space group C2/ c. The coordination geometry is a distorted square pyramid with the nitrido ligand at the apex.

Synthesis and X-ray crystal structure of a heptametallic complex containing the unbridged FeSnFeHgFeSnFe skeleton

The reaction between [NEt4]2[Cl2Sn{Fe(CO)4}2] and [ClHgMo(CO)3(η-C5H5)] affords the air-stable compound [NEt4]2[{(OC)4FeSnCl2Fe(CO)4}2Hg]1 with high yields; X-ray crystallography has proved that the anion contains the novel unsupported heptametallic FeSnFeHgFeSnFe skeleton.

Novel intramolecularly stabilized organogallium and organoindium compounds and their use in MOVPE

Novel organogallium and organoindium compounds containing the intramolecularly stabilizing dimethylaminopropyl, diethylaminopropyl or dimethylaminobutyl ligand have been synthesized for use in MOVPE. Syntheses and NMR investigations of the moderately air-stable compounds are reported. Using those compounds, GaAs and InP semiconductor layers of good quality could be grown in initial experiments.

The tin(IV) coordination environment in di-n-butyltin di- p-bromobenzoate, a monomeric diorganotin ester

Di-n-butyltin di- p-bromobenzoate is an air-stable compound which crystallizes in the monoclinic space group C2/ c with a 21.346(4), b 6.962(4), c 17.174(6) Å, β 107.81(2)°; Z = 4. The refinement of the structure from 1561 I > 3σ( I) Mo- K α reflections converged at R = 0.033. The monomeric molecule lies on a two-fold rotation axis passing through the tin atom. The coordination geometry is best described as a skew-trapezoidal bipyramid, in which the carboxylate (bite angle 54.0(1)°) oxygen atoms comprise the trapezoidal plane (SnO I 2.075(3), SnO II 2.635(4) Å), with the α-carbon (SnC 2.114(5) Å, CSnC′ 130.6(2)°) atoms tilting over the longest edge (O IISnO II′ 171.1(1)°) of this plane.

ChemInform Abstract: Preparation, Structure, and Nuclear Magnetic Resonance Properties of the Nine‐Vertex nido‐Rhenaborane ((PMe2Ph)3H2ReB8H11) and Some Related Chemistry.

AbstractThermolysis of the 9‐ethoxy substituted nido‐6‐rhenadecaborane (I) results in a quantitative cluster degradation to give the nine‐vertex nido‐derivative (II).

Preparation, Chemical, and Structural Characterization of Some Molybdenum(III) and Tungsten(III) Coordination Compounds Containing 1‐(4‐pyridyl)pyridinium Cation

Abstract1‐(4‐pyridyl)pyridinium ion (C10H10N22+, (Py2)H2+) precipitates from the hydrochloric acid solution of (NH4)2MoCl5 · H2O sparingly soluble (Py2)HMoCl5 · H2O. This unreactive, air stable compound crystallizes in the orthorhombic unit cell with a = 12.895(4), b = 6.914(2), c = 16.388(7) Å, Z = 4. The ionic structure contains octahedral MoCl5 · H2O2– and (Py2)H2+. The bond lengths MoCl are between 2.406(3) to 2.446(4) Å. The bond length MoO(H2O) is 2.19(1) Å. Planar pyridine rings of the cation are rotated around the common axis by 38°. Anions are located in layers at Z = 1/4 and 3/4. Between the layers (Py2)H2+ cations are situated.(Py2)MX4Py2 (M = Mo, W; X = Cl, Br; Py = Pyridine) with deprotonated (Py2)H2+ are prepared from the solutions of (PyH)MoX4Py2 in aqueous ammonia to which (Py2)HCl2 was added. All four compounds crystallize in the triclinic crystal system. Unit cell dimensions are comparable. The stability of the compounds against oxidation and substitution could have its origin in the low solubility.

Preparation, structure, and nuclear magnetic resonance properties of the nine-vertex nido-rhenaborane [(PMe2Ph)3H2ReB8H11] and some related chemistry

Thermolysis of [6,6,6-(PMe2Ph)3-6-H-nido-6-ReB9H12-9-(OEt)](1) in C2D2Cl4 solution gives the new, pale yellow air-stable compound [2,2,2-(PMe2Ph)3-2,2-H2-nido-2-ReB8H11](2) in 80% yield. Crystals of the CH2Cl2 hemisolvate of (2) are monoclinic, space group P21/c, with a= 1 130.0(3), b= 1 292.2(3), c= 2 424.0(5) pm, β= 94.15(2)°, and Z= 4; the molecular structure was refined to R= 0.0399, R′= 0.0454. The detailed n.m.r. behaviour of compound (2) together with data for previously reported rhodium and iridium analogues permits the location of the substituent site on previously unconfirmed [2-(CO)-2,2-(PMe3)2-nido-2-IrB8H10-3-Cl] and thence provides information on mechanistic pathways for the formation of these and related metallaboranes. Detailed n.m.r. data for the non-metalla analogues [B9H12]– and previously unassigned [3-ClB9H11]– provide information on their mechanism of formation and a comparison with the metallaborane analogues. The n.m.r. work includes extensive use of [11B–11B]-COSY and [1H–1H]-COSY experiments and establishes general points.

Synthesis, structure, and reactions of a dimeric rhodium(I) complex with bridging σ- and π-bonded 2,5-dimethylpyrrolido ligands

Lithium 2,5-dimethylpyrrolide reacts with [RhCl(CO) 2] 2 in THF to give the novel dimeric Rh-carbonyl ( 1). The X-ray structure of 1 shows that two Rh(CO) 2 moieties are coordinated by two bridging pyroole rings, where each ring acts as both a σ and a π donor. Reactions of 1 with either PPh 3 ( 2) or AsPh 3 ( 3) proceed rapidly and produce yellow air stable compounds. The X-ray structure of 2 confirms that it is a square-planar Rh 1 complex with two PPh 3 groups in trans positions and the remaining positions occupied by CO and a σ-bonded pyrrolide ion. Corresponding reactions with lithium 2,5-dimethylpyrrolide and [IrCl(CO) 3] n yield products very similar to compounds 1– 3. Preliminary investigations of reactions between [RhCl(CO) 2] 2 and the anions of 3,4-dimethylpyrrole and of pyrrole suggested that the products were a mixture of compounds which were not identified.

Pentamethylcyclopentadienylrhodaborane chemistry. Part 2. The reaction of [6-(η5-C5Me5)-nido-6-RhB9H13] with dimethylphenylphosphine, and the characterization of [5-(η5-C5Me5)-nido-5-RhB9H11-7-(PMe2Ph)], [2-(η5-C5Me5)-closo-2-RhB9H7-3,10-(PMe2Ph)2],* and [2-(η5-C5Me5)-nido-2-RhB8H10-5-(PMe2Ph)] by X-ray diffraction analysis and nuclear magnetic resonance spectroscopy

Reaction of [6-(η5-C5Me5)-nido-6-RhB9H13](1) with an excess of PMe2Ph in CH2Cl2 solution at room temperature yields three air-stable compounds: red-orange [5-(η5-C5Me5)-nido-5-RhB9H11-7-(PMe2Ph)](2; 35%), yellow [2-(η5-C5Me5)-closo-2-RhB9H7-3,10-(PMe2Ph)2](3; 25%), and orange [2-(η5-C5Me5)-nido-2-RhB8H10-5-(PMe2Ph)](4; ca. 7%). Crystals of (2) are triclinic, space group P, with a= 940.9(2), b= 875.2(2), c= 1 561.4(2) pm, α= 99.06(2), β= 103.45(1), γ= 91.57(2)°, and Z= 2. Crystals of (3) are monoclinic, space group P21/a, with a= 1 406.4(3), b= 1 231.7(3), c= 1 812.3(3) pm, β= 94.01 (1)°, and Z= 4. These compounds, and compound (4), were also characterized by n.m.r. spectroscopy. Structural and bonding considerations are discussed and some mechanistic implications are briefly considered.