Angle‐resolved XPS of fluorinated and semi‐fluorinated side‐chain polymers

Angle‐resolved XPS data (elemental quantification and high‐energy‐resolution C 1s) are presented for ten polymers with side‐chains of the form ? OCO(CF₂)_yF, ? COO(CH₂)₂OCO(CF₂)_yF (y = 1, 2, 3) and ? COO(CH₂)_x(CF₂)_yF (x = 1, y = 1, 2, 3; x = 2, y = 8). Particular attention was paid to charge compensation and speed of data acquisition, with co‐addition from multiple fresh samples to give spectra with good energy resolution and good signal‐to‐noise ratio free from the effects of x‐ray‐induced degradation. Water contact angles for the polymers are also reported. The XPS data demonstrate preferential surface segregation of fluorine‐containing groups for all but the shortest side‐chain polymer, where the ? OCOCF₃ side‐chain either does not surface segregate or is too short for surface segregation to be detectable by angle‐resolved XPS. In the other polymers studied the relative positions of functional groups in the side‐chains correlate with the angle‐resolved behaviour of the corresponding C 1s components. This shows that the surface side‐chains are oriented towards the polymer surface. For the ? COO(CH₂)₂OCO(CF₂)_yF (y = 1) side‐chain, the angle‐resolved C 1s data suggest reduced ordering and linearity compared with y = 2 and 3. For any particular series of polymers, e.g. ? COO(CH₂)_x(CF₂)_yF, the water contact angles increase with y, consistent with burying of the hydrophilic ester groups as y increases. For any particular value of y the sequence of water contact angles is ? COO(CH₂)_x(CF₂)_yF > ? OCO(CF₂)_yF ～ ? COO(CH₂)₂OCO(CF₂)_yF, suggesting greater ordering and density of fluorocarbon species at the surface of the ? COO(CH₂)_x(CF₂)_yF side‐chain polymers compared with the other polymers studied. For the ? COO(CH₂)₂(CF₂)₈F polymer a water contact angle of 124° is measured, which is greater than that of poly(tetrafluoroethene). The ? COO(CH₂)₂OCO(CF₂)F polymer is unusual in that it shows a particularly low water contact angle (83° ), suggesting that the probe fluid is able to sense both ester groups, consistent with the reduced ordering of the side‐chain detected by angle‐resolved XPS. Copyright © 2004 John Wiley & Sons, Ltd.     

Mixed‐Halide CH3NH3PbI3−xXx (X=Cl,Br, I) Perovskites: Vapor‐Assisted Solution Deposition and Application as Solar Cell Absorbers

There have been recent reports on the formation of single‐halide perovskites, CH₃NH₃PbX₃ (X=Cl, Br, I), by means of vapor‐assisted solution processing. Herein, the successful formation of mixed‐halide perovskites (CH₃NH₃PbI_3?xX_x) by means of a vapor‐assisted solution method at ambient atmosphere is reported. The perovskite films are synthesized by exposing PbI₂ film to CH₃NH₃X (X=I, Br, or Cl) vapor. The prepared perovskite films have uniform surfaces with good coverage, as confirmed by SEM images. The inclusion of chlorine and bromine into the structure leads to a lower temperature and shorter reaction time for optimum perovskite film formation. In the case of CH₃NH₃PbI_3?xCl_x, the optimum reaction temperature is reduced to 100 °C, and the resulting phases are CH₃NH₃PbI₃ (with trace Cl) and CH₃NH₃PbCl₃ with a ratio of about 2:1. In the case of CH₃NH₃PbI_3?xBr_x, single‐phase CH₃NH₃PbI₂Br is formed in a considerably shorter reaction time than that of CH₃NH₃PbI₃. The mesostructured perovskite solar cells based on CH₃NH₃PbI₃ films show the best optimal power conversion efficiency of 13.5 %, whereas for CH₃NH₃PbI_3?xCl_x and CH₃NH₃PbI_3?xBr_x the best recorded efficiencies are 11.6 and 10.5 %, respectively.     

Non‐hydrogenated amorphous germanium carbide with adjustable microstructure and properties: a potential anti‐reflection and protective coating for infrared windows

Amorphous non‐hydrogenated germanium carbide (a‐Ge_1?xC_x) films have been deposited using magnetron co‐sputtering technique by varying the sputtering power of germanium target (P_Ge). The effects of P_Ge on composition and structure of the a‐Ge_1?xC_x films have been analyzed. The FTIR spectrum shows that the C–Ge bonds were formed in the a‐Ge_1?xC_x films according to the absorption peak at ~610 cm^?1. The Raman results indicate that the amorphous films also contain both Ge and C clusters. The XPS results reveal that the carbon concentration decreased as P_Ge increased from 40 to 160 W. The fraction of sp³ C–C bonds remains almost constant when increasing P_Ge from 40 to 160 W. The sp² C–C content of a‐Ge_1?xC_x film decreases gradually to 35.9% with P_Ge up to 160 W. Nevertheless, sp³ C–Ge sites rose with increasing P_Ge. Furthermore, the hardness and the refractive index gradually increased with increasing P_Ge. The excellent optical transmission of annealed a‐Ge_1–xC_x double‐layer coating at 400 °C suggests that a‐Ge_1?xC_x films can be used as an effective anti‐reflection coating for the ZnS IR window in the wavelength region of 8–12 µm, and can endure higher temperature than hydrogenated amorphous germanium carbide do. Copyright © 2012 John Wiley & Sons, Ltd.     

Formation of T‐Shaped versus Charge‐Transfer Molecular Adducts in the Reactions Between Bis(thiocarbonyl) Donors and Br2 and I2

The reactions of 4,5,6,7‐tetrathiocino‐[1,2‐b:3,4‐b′]‐1,3,8,10‐tetrasubstituted‐diimidazolyl‐2,9‐dithiones (R₂,R′₂‐todit; 1 : R=R′=Et; 2 : R=R′=Ph; 3 : R=Et, R′=Ph) with Br₂ exclusively afforded 1:1 and 1:2 “T‐shaped” adducts, as established by FT‐Raman spectroscopy and single‐crystal X‐ray diffraction in the case of complex 1? 2 Br₂. On the other hand, the reactions of compounds 1 – 3 with molecular I₂ provided charge‐transfer (CT) “spoke” adducts, among which the solvated species 3? 2 I₂ ? (1?x)I₂ ? x CH₂Cl₂ (x=0.94) and ( 3 )₂ ? 7 I₂ ? x CH₂Cl_2, (x=0.66) were structurally characterized. The nature of all of the reaction products was elucidated based on elemental analysis and FT‐Raman spectroscopy and supported by theoretical calculations at the DFT level.     

Synthesis and Characterization of the Germanium Sulfonate Ge(CH3SO3)2 – a 3D Coordination Network Solid

The reaction of germanium(II)‐bis(2‐methoxyphenyl)methoxide with methanesulfonic acid provides the germanium(II) sulfonate Ge(CH₃SO₃)₂ ( 1 ), which was characterized by X‐ray diffraction, elemental analysis, NMR spectroscopy, and IR spectroscopy. The decomposition process of 1 was investigated by thermal gravimetric analysis (TGA) and temperature‐dependent X‐ray powder diffraction (PXRD) and both are consistent with the formation of GeO₂ as major final product. Single crystal X‐ray diffraction at 110 K revealed the chiral tetragonal space group P4₁2₁2 and formation of a three‐dimensional (3D) coordination network solid. The 3D network is composed of interconnected twenty four‐membered rings comprising bridging methanesulfonate groups, which link the germanium atoms.     

Reverse‐Vesicle Formation of Organic–Inorganic Polyoxometalate‐Containing Hybrid Surfactants with Tunable Sizes

The formation of reverse‐vesicular structures of the polyoxometalate‐containing hybrid surfactants [nBu₄N]₃[MnMo₆O₁₈{(OCH₂)₃? CNHCO(CH₂)_n?2CH₃}₂] (Mn‐Anderson‐C_n, n=6, 16) in nonpolar medium was achieved by titrating toluene into Mn‐Anderson‐C_n/acetonitrile (MeCN) solution. Stepwise change of the solvent polarity induces self‐association of the hydrophilic Mn‐Anderson cluster on the hybrid amphiphiles. The reverse‐vesicle formation was characterized by laser light scattering and further confirmed by transmission electron microscopy techniques, and the vesicle sizes increase with increasing toluene contents. The assembly process was accelerated at an elevated temperature. The length of the alkyl tails on the hybrid surfactants has a minor effect on the vesicle sizes, because the strong attraction between the polyoxometalate clusters is more dominant in the reverse‐vesicle formation.     

Synthesis of syn‐2,4‐Dimercapto‐1,3,2,4‐dithiadigermetane and Its Application to Ge2PdS4 Cluster Synthesis

The sulfurization of DmpGeH₃ (Dmp=2,6‐dimesitylphenyl) afforded the trinuclear germanium sulfide [DmpGe(μ‐S)]₂(μ‐S)₂Ge(SH)‐Dmp and a series of polythiadigermabicyclo[x.1.1]alkanes (x=3, 4, 5). The reduction of the S? S bonds of these germabicycloalkanes by NaBH₄ at 0 °C afforded the dinuclear mercaptogermane syn‐[DmpGe(SH)(μ‐S)₂Ge(SH)‐Dmp] ( 5 ) in good yield. The reaction of [Pd(dppe)Cl₂] (dppe=1,2‐bis(diphenylphosphanyl)ethane) and the dilithium salt of 5 prepared in situ by the addition of nBuLi (2 equiv) gave the Ge₂PdS₄ cluster [DmpGe(μ‐S)]₂[(μ‐S)₂Pd(dppe)], in which the dithiadigermetanedithiolate is bound to the Pd atom at the two thiolato sulfur atoms. The same reaction with [Pd(PPh₃)₂Cl₂] gave another Ge₂PdS₄ cluster, [DmpGe(μ‐S)]₂[(μ‐S)₂Pd(PPh₃)], but with the dithiadigermetanedithiolate and the Pd center conjoined through a μ‐S atom between the two germanium atoms in addition to the two thiolato sulfur atoms to form a highly distorted cluster core. The formation of two different types of Ge₂PdS₄ clusters represents the usefulness of 5 in the synthesis of various polynuclear complexes composed of germanium and transition metals.     

Formation pathways of DMSO2 in the addition channel of the OH‐initiated DMS oxidation: A theoretical study

The production of dimethyl sulfoxide (DMSO) and dimethyl sulfone (DMSO₂) in the dimethyl sulfide (DMS) degradation scheme initiated by the hydroxyl (OH) radical has been shown to be very sensitive to nitrogen oxides (NO_x) levels. In the present work we have explored the potential energy surfaces corresponding to several reaction pathways which yield DMSO₂ from the CH₃S(O)(OH)CH₃ adduct [including the formation of CH₃S(O)(OH)CH₃ from the reaction of DMSO with OH] and the reaction channels that yield DMSO or/and DMSO₂ from the CH₃S(O₂)(OH)CH₃ adduct are also studied. The formation of the CH₃S(O₂)(OH)CH₃ adduct from CH₃S(OH)CH₃ (DMS‐OH) and O₂ was analyzed in our previous work. All these pathways due to the presence of NO_x (NO and NO₂) and also due to the reactions with O₂, OH and HO₂ are compared with the objective of inferring their kinetic relevance in the laboratory experiments that measure DMSO₂ (and DMSO) formation yields. In particular, our theoretical results clearly show the existence of NO_x‐dependent pathways leading to the formation of DMSO₂, which could explain some of these experimental results in comparison with experimental measurements carried out in NO_x‐free conditions. Our results indicate that the relative importance of the addition channel in the DMS oxidation process can be dependent on the NO_x content of chamber experiments and of atmospheric conditions. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009     

Water exchange on beryllium complexes: part VIII – influence of neutral electron pair donors

In this article, water exchange reactions on [Be(L)(H₂O)₃]²⁺ (L?=?NH_{3? x} (CH₃) _x , PH_{3? x} (CH₃) _x , AsH_{3? x} (CH₃) _x , OH_{2? x} (CH₃) _x , SH_{2? x} (CH₃) _x , SeH_{2? x} (CH₃) _x , pyridine, 4-fluoropyridine, 4-bromopyridine, 4-chloropyridine, 4-hydroxypyridine, 4-thiolopyridine, 4-selenidopyridine, 4-nitrilopyridine, 1,4-diazine, 1,3,5-triazine, HCN, acetonitrile, and benzonitrile) are examined, utilizing the B3LYP//6-311?+?G** density functional for geometry optimizations, and B3LYP//6-311?+?G** both with and without the CPCM solvent model as well as MP2(full)//6-311?+?G** for subsequent single-point energy calculations. In all examined cases, the results prove that these complexes show associative interchange mechanisms for water exchange. With the exception of the NH _x (CH₃)_{3? x} series of ligands, activation energy barriers vary little, making these ligands mostly spectator ligands. Geometrical parameters vary mainly with the ligand size.     

Organosilyl/‐germyl Polyoxotungstate Hybrids for Covalent Grafting onto Silicon Surfaces: Towards Molecular Memories

Organosilyl/‐germyl polyoxotungstate hybrids [PW₉O₃₄(tBuSiO)₃Ge(CH₂)₂CO₂H]^3? ( 1 a ), [PW₉O₃₄(tBuSiO)₃Ge(CH₂)₂CONHCH₂C?CH]^3? ( 2 a ), [PW₁₁O₃₉Ge(CH₂)₂CO₂H]^4? ( 3 a ), and [PW₁₁O₃₉Ge(CH₂)₂CONHCH₂C≡CH]^4? ( 4 a ) have been prepared as tetrabutylammonium salts and characterized in solution by multinuclear NMR spectroscopy. The crystal structure of (NBu₄)₃ 1 a? H₂O has been determined and the electrochemical behavior of 1 a and 2 a has been investigated by cyclic voltammetry. Covalent grafting of 2 a onto an n‐type silicon wafer has been achieved and the electrochemical behavior of the grafted clusters has been investigated. This represents the first example of covalent grafting of Keggin‐type clusters onto a Si surface and a step towards the realization of POM‐based multilevel memory devices.     

Soluble Polystyrenes Functionalized by Triorgano[(1‐oxoalkyl)oxy]stannanes (=Triorganotin Carboxylates): Synthesis,Structure, and Anion‐Recognition Characteristics

Polystyrene copolymers of the type ( P −H)_1−x( P −(CH₂)_n−COOSnR₃)_x containing [(1‐oxoalkyl)oxy]triphenylstannane or tributyl[(1‐oxoalkyl)oxy]stannanes as side chains ( P −H=styrene; P −(CH₂)_n−COOSnR₃ =para‐substituted styrene‐like monomeric unit with R=Ph (x=0.1), Bu (x=0.5); n=2–4) were investigated. The tributyl[(1‐oxoalkyl)oxy]stannane copolymer was prepared by direct conversion of the corresponding copolymeric methyl esters with hexabutyldistannoxane. By contrast, the [(1‐oxoalkyl)oxy]triphenylstannane copolymer could be prepared only by a procedure involving two reaction steps consisting of a preliminary hydrolysis of the related methyl ester ( P −H)_1‐x( P −(CH₂)_n−COOMe)_x followed by functionalization of the corresponding poly(carboxylic acid) ( P −H)_1‐x( P −(CH_2n−COOH)_x with hydroxytriphenylstannane. Attempts to directly convert the methyl ester with hydroxytriphenylstannane or hexaphenyldistannoxane led to the formation of uncompletely functionalized product. The structure of the stannane‐functionalized polymers was investigated in solution and solid state by NMR, IR, and thermal analysis. The tributylstannane and triphenylstannane copolymers were assessed as chloride‐selective anion carriers in polymeric‐liquid‐membrane potentiometric ion‐selective electrodes.     

Heterometallic Complexes with Gold(I) Metalloligands: Self‐Assembly of Helical Dimers Stabilized by Weak Intermolecular Interactions and Solvophobic Effects

New gold(I) alkynyl metalloligands bpylC?CAuL, bpyl′C?CAuPPh₃, and PPN[Au(C?Cbpyl′)₂] (bpyl or bpyl′=2,2′‐bipyridin‐5‐yl or ?4‐yl, respectively; L=PMe_xPh_3?x (x=1–3), P(C₆H₃Me₂‐3,5)₃, PCy₃, XyNC) have been synthesized. Ligands bpylC?CH and metalloligands bpylC?CAuL (L=PPh₃, PMePh₂, PCy₃, CNXy) react with MX₂ (M=Fe, Zn, X=ClO₄; M=Co, X=BF₄) to give complexes [M(bpylC?CZ)₃]X₂ (Z=H or AuL). In most cases, these complexes are mixtures of fac and mer isomers in a statistical distribution, in both CH₂Cl₂ and MeCN. However, for L=PPh₃, the fac isomer is dominant in MeCN. NMR and ESI‐MS studies, together with the crystal structure of [Co(bpylC?CAuPPh₃)₃](BF₄)₂, suggest that this solvent dependence is originated by the formation of helical dimers between two fac complexes in MeCN. These dimers are stabilized by solvophobic effects and multiple intermolecular interactions. Complex [Fe(Ph₃PAuC?CbpdiylC?CAuPPh₃)₃](ClO₄)₂ (bpdiyl=2,2′‐bipyridin‐5,5′‐diyl) was obtained by reaction of three diauro diethynylbipyridines and Fe(ClO₄)₂.     

Enantiomerically Pure Phosphaalkene–Oxazolines (PhAk‐Ox): Synthesis,Scope and Copolymerization with Styrene

The design of a synthetic route to a class of enantiomerically pure phosphaalkene–oxazolines (PhAk‐Ox) is presented. The condensation of a lithium silylphosphide and a ketone (the phospha‐Peterson reaction) was used as the P?C bond‐forming step. Attempted condensation of PhC(?O)Ox (Ox=CNOCH(iPr)C H₂) and MesP(SiMe₃)Li gave the unusual heterocycle (MesP)₂C(Ph)?CN‐(S)‐CH(iPr)CH₂O ( 3 ). However, PhAk‐Ox (S,E)‐MesP?C(Ph)CMe₂Ox ( 1 a ) was successfully prepared by treating MesP(SiMe₃)Li with PhC(?O)CMe₂Ox (52 %). To demonstrate the modularity and tunability of the phospha‐Peterson synthesis several other phosphaalkene–oxazolines were prepared in an analogous manner to 1 a : TripP?C(Ph)CMe₂Ox ( 1 b ; Trip=2,4,6‐triisopropylphenyl), 2‐iPrC₆H₄P?C(Ph)CMe₂Ox ( 1 c ), 2‐tBuC₆H₄P?C(Ph)CMe₂Ox ( 1 d ), MesP?C(4‐MeOC₆H₄)CMe₂Ox ( 1 e ), MesP?C(Ph)C(CH₂)₄Ox ( 1 f ), and MesP?C(3,5‐(CF₃)₂C₆H₃)C(CH₂)₄Ox ( 1 g ). To evaluate the PhAk‐Ox compounds as prospective precursors to chiral phosphine polymers, monomer 1 a and styrene were subjected to radical‐initiated copolymerization conditions to afford [{MesPC(Ph)(CMe₂Ox)}_x{CH₂CHPh}_y]_n ( 9 a : x=0.13n, y=0.87n; GPC: M_w=7400 g mol^?1, PDI=1.15).     

Reactivity of Fluoro‐Substituted Bis(thiocarbonyl) Donors with Diiodine: An XRD,FT–Raman,and DFT Investigation

The reactions of 1,3,8,10‐tetrakis(4′‐fluorophenyl)‐4,5,6,7‐tetrathiocino[1,2‐b:3,4‐b′]diimidazolyl‐2,9‐dithione ( 4 ) and molecular diiodine afforded spoke adducts with stoichiometries 4·I2 and 4? 3I₂, isolated in the compound 4? 3I₂ ? xCH₂Cl₂ ? (1?x)I₂ (x=0.70), and characterized by single‐crystal XRD and FT–Raman spectroscopy. The nature of the reaction products was investigated under the prism of theoretical calculations carried out at the DFT level. The structural data, FT–Raman spectroscopy, and quantum mechanical calculations agree in indicating that the introduction of fluorophenyl substituents results in a lowering of the Lewis basicity of this class of bis(thiocarbonyl) donors compared with alkyl‐substituted tetrathiocino donors and fluorine allows for extended interactions that are responsible for solid‐state crystal packing.     

The Energy Landscape of Uranyl–Peroxide Species

Nanoscale uranyl peroxide clusters containing UO₂²⁺ groups bonded through peroxide bridges to form polynuclear molecular species (polyoxometalates) exist both in solution and in the solid state. There is an extensive family of clusters containing 28 uranium atoms (U₂₈ clusters), with an encapsulated anion in the center, for example, [UO₂(O₂)_3?x(OH)_x^4?], [Nb(O₂)₄^3?], or [Ta(O₂)₄^3?]. The negative charge of these clusters is balanced by alkali ions, both encapsulated, and located exterior to the cluster. The present study reports measurement of enthalpy of formation for two such U₂₈ compounds, one of which is uranyl centered and the other is peroxotantalate centered. The [(Ta(O₂)₄]‐centered U₂₈ capsule is energetically more stable than the [(UO₂)(O₂)₃]‐centered capsule. These data, along with our prior studies on other uranyl–peroxide solids, are used to explore the energy landscape and define thermochemical trends in alkali–uranyl–peroxide systems. It was suggested that the energetic role of charge‐balancing alkali ions and their electrostatic interactions with the negatively charged uranyl–peroxide species is the dominant factor in defining energetic stability. These experimental data were supported by DFT calculations, which agree that the [(Ta(O₂)₄]‐centered U₂₈ capsule is more stable than the uranyl‐centered capsule. Moreover, the relative stability is controlled by the interactions of the encapsulated alkalis with the encapsulated anion. Thus, the role of alkali‐anion interactions was shown to be important at all length scales of uranyl–peroxide species: in both comparing clusters to clusters; and clusters to monomers or extended solids.     

Synthese „anorganischer”︁ Tintenfisch-Moleküle. II

Synthesis of “Inorganic” Pode-type Molecules. II The reaction of the amino compounds Me_yB? NMe₂ (B ? As, y ? 2; B ? Si, y ? 3) with 1, n-dioles results in the formation of the compounds HO(CH₂)_nOBMe_y. These compounds can be used as the arms of pode-type molecules Me_xA[? O(CH₂)_nOBMe_y]_z with A ? Si, As. The influence of A, B, n, and z in the rearrangement of these molecules is examined. A second type of pode molecules can be prepared by the reaction of Me₂As? R? OH (R ? CH₂CH₂, CH₂CH₂(OCH₂CH₂)₂) with the amino compounds Me_x(NMe₂)_z (A ? As, Si). These reactions result in the formation of molecules as Me_xA(ORAsMe₂)_z.     

C−−H activation on aluminum-vanadium bimetallic oxide cluster anions

Aluminum–vanadium bimetallic oxide cluster anions (BMOCAs) have been prepared by laser ablation and reacted with ethane and n‐butane in a fast‐flow reactor. A time‐of‐flight mass spectrometer was used to detect the cluster distribution before and after the reactions. The observation of hydrogen‐containing products AlVO₅H^? and Al_xV_4?xO_11?xH^? (x=1–3) strongly suggests that AlVO₅^? and Al_xV_4?xO_11?x^? (x=1–3) can react with ethane and n‐butane by means of an oxidative dehydrogenation process at room temperature. Density functional theory studies have been carried out to investigate the structural, bonding, electronic, and reactive properties of these BMOCAs. Terminal‐oxygen‐centered radicals (O_t^.) were found in all of the reactive clusters, and the O_t^. atoms, which prefer to be bonded with Al rather than V atoms, are the active sites of these clusters. All the hydrogen‐abstraction reactions are favorable both thermodynamically and kinetically. To the best of our knowledge, this is the first example of hydrogen‐atom abstraction by BMOCAs and may shed light on understanding the mechanisms of C? H activation on the surface of alumina‐supported vanadia catalysts.     

Synthesis of fluorosilicone having highly fluorinated alkyl side chains based on the hydrosilylation of fluorinated olefins with polyhydromethylsiloxane

Hydrosilylation of fluorinated olefins with polyhydromethylsiloxane (PHMS) in the presence of a platinum catalyst was investigated to synthesize fluorosilicone having highly fluorinated alkyl side chains (R_f; C_nF_2n+1? ). The hydrosilylation of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10‐heptadecafluoro‐1‐decene (C₈F₁₇CH?CH₂) ( 1 ) with poly(dimethylsiloxane‐co‐hydromethylsiloxane) {(CH₃)₃SiO[? (H)CH₃SiO? ]₈[? (CH₃)₂ SiO? ]₁₈Si(CH₃)₃} ( 4 ) converted the hydrogen bonded to silicons into the 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10‐heptadecafluorodecyl group or fluorine bonded to silicons in the ratio of about 52:48, and the formation of the byproduct C₇F₁₅CF?CHCH₃ ( 8 ) was observed. The hydrosilylation of 7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,14‐heptadecafluoro‐4‐oxa‐1‐tetradecene (C₈F₁₇CH₂CH₂OCH₂CH?CH₂) ( 2 ) with 4 converted the hydrogen bonded to silicons into the 7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,14‐heptadecafluoro‐4‐oxa‐tetradocyl group bonded to silicons, but an excess amount of 2 was required to complete the reaction because the isomerization of 2 occurred in part to form C₈F₁₇CH₂CH₂OCH?CHCH₃ ( 9 ). The hydrosilylation of 4,4,5,5,6,6,7,7,8,8,9,9, 10,10,11,11,11‐heptadecafluoro‐1‐undecene (C₈F₁₇CH₂CH?CH₂) ( 3 ) with 4 converted the hydrogen bonded to silicons into the 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11‐heptadecafluoroundecyl group bonded to silicons. This type of fluorinated olefin was successfully applied to the hydrosilylation with other PHMS's that involved a homopolymer of PHMS and a cyclic PHMS. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3120–3128, 2002     

Stepwise Assembly of MII7 Clusters Revealed by Mass Spectrometry,EXAFS, and Crystallography

The square‐planar monomer NiL₂ ( Ni₁ ), L=2‐ethoxy‐6‐(N‐methyl‐iminomethyl)phenolate, reacts with M(H₂O)₆(ClO₄)₂, M=Ni or Co, to form heptanuclear disks [Co_xNi_7?x(OH)₆(L)₆](ClO₄)₂ ? 2 CH₃CN ( Co _x Ni_7?x , x=0–7) and the co‐crystal [Co_xNi_7?x(OH)₆L₆][NiL₂](ClO₄)₂ ? 2 CH₃CN ( Co _x Ni_7?x ‐Ni₁ ) under ambient conditions. It has proved possible to explore the bottom‐up assembly process of Co _x Ni_7?x and Co _x Ni_7?x ‐Ni₁ in real time. The final products have been characterized by thermogravimetric analysis, IR, elemental analysis, ICP‐MS, and single‐crystal X‐ray diffraction. Time‐dependent mass spectrometry (MS) revealed the following reaction steps: Ni₁→[M₂L₃]⁺→[M₄(OH)₂L₄]²⁺→[M₇(OH)₆L₆]²⁺. In contrast, the reaction of Ni₁ with Zn²⁺ only reaches halfway, and crystallographic evidence indicates a butterfly structure for [Zn₂Ni₂(OH)₂Cl₂] ( Zn₂Ni₂ ), an intermediate that is difficult to isolate in the above Ni‐Co series. A summation method has been used to analyze the MS of bimetallic clusters with very similar atomic masses, as is the case for Co and Ni. The results provide ample information on the distribution of Co and Ni within each cluster and their statistical distribution within selected crystals.