Thermal decomposition of di-t-butyl peroxide in the presence of (CH3)2CCH2: Reactions of CH3, (CH3)2ĊCH2CH3, and (CH3)2ĊCH2C(CH3)2CH2CH3 radicals

A study of the reaction initiated by the thermal decomposition of di-t-butyl peroxide (DTBP) in the presence of (CH₃)₂C?CH₂ (B) at 391–444 K has yielded kinetic data on a number of reactions involving CH₃ (M·), (CH₃)₂CCH₂CH₃ (MB·) and (CH₃)₂?CH₂C(CH₃)₂CH₂CH₃ (MBB·) radicals. The cross-combination ratio for M· and MB· radicals, rate constants for the addition to B of M· and MB· radicals relative to those for their recombination reactions, and rate constants for the decomposition of DTBP, have been determined. The values are, respectively, where θ = RT ln 10 and the units are dm^3/2 mol^?1/2 s^?1/2 for k₂/k and k₉/k, s^?1 for k₀, and kJ mol^?1 for E. Various disproportionation-combination ratios involving M·, MB·, and MBB· radicals have been evaluated. The values obtained are: Δ₁(M·, MB·) = 0.79 ± 0.35, Δ₁(MB·, MB·) = 3.0 ± 1.0, Δ₁(MBB·, MB·) = 0.7 ± 0.4, Δ₁(M·, MBB·) = 4.1 ± 1.0, Δ₁(MB·, MBB·) = 6.2 ± 1.4, and Δ₁(MBB·, MBB·) = 3.9 ± 2.3, where Δ₁ refers to H-abstraction from the CH₃ group adjacent to the center of the second radical, yielding a 1-olefin. © 1994 John Wiley & Sons, Inc.     

Dimethylarsenazid (CH3)2AsN3, Dimethylwismutazid (CH3)2BiN3 und Dimethylthalliumzid (CH3)2TiN3

The reaction of (CH₃)₂AsJ and AgN₃ yields (CH₃)₂AsN₃; a colourless liquid (b. p. 136°C) which dissolves as a monomeric in benzene. (CH₃)₂BiN₃ is precipitated in form of colourless needles (dec. temp. 150°C) from an etherical solution of Bi(CH₃)₃ and HN₃. According to its vibrational and mass spectra the molecules are not associated although the (CH₃)₂BiN₃ is not soluble; dipole association of this polar molecules is assumed for the crystal structure. (CH₃)₂TlN₃ can be obtained from TI(CH₃)₃ and ClN₃ as well as from (CH₃)₂TlOH and HN₃ in form of colourless needles and leaves (dec. temp. 245°C). According to its vibrational spectra it has an ionic structure, (CH₃? Tl? CH₃)⁺N^?₃.     

Synthesis and Characterization of （CH3CH2CH2CH2NH3）2SnBr6

1 INTRODUCTION Recently, the researches on inorganic-organic hy-brid compounds represent an advanced field in mate-rial science[1]. At the molecular level, the combina-tion of two extremely different components providesan avenue to design new hybrid materials as well asthe ability to modulate properties of one or more ofthe components[2～6]. Some attractive properties, suchas efficient luminescence[2～4], ideal thermal and me-chanical stability, interesting magnetic[5], non-linearoptical[…     

Comparison between CH3(CH2)15SH and CF3(CF2)3(CH2)11SH monolayers on electrodeposited silver

In this paper, two monolayers self-assembled on a silver substrate are compared: a monolayer of n-hexadecanethiol and a monolayer of n-11-perfluorobutylundecanethiol. The protecting properties of both monolayers have been extensively studied by X-ray photoelectron spectroscopy, contact angle, polarization modulation infrared reflection absorption spectroscopy, conventional electrochemical techniques (polarization curves and electrochemical impedance spectroscopy), and scanning vibrating electrode technique. Both monolayers were successfully self-assembled but organization is slightly different, the fluorinated segment introduces small disorganization. Nevertheless, good homogeneous corrosion protection is observed for each monolayer.     

New superhindered polydentate polyphosphine ligands P(CH2CH2P(t)Bu2)3, PhP(CH2CH2P(t)Bu2)2, P(CH2CH2CH2P(t)Bu2)3, and their ruthenium(II) chloride complexes

The synthesis and characterization of the extremely hindered phosphine ligands, P(CH(2)CH(2)P(t)Bu(2))(3) (P(2)P(3)(tBu), 1), PhP(CH(2)CH(2)P(t)Bu(2))(2) (PhP(2)P(2)(tBu), 2), and P(CH(2)CH(2)CH(2)P(t)Bu(2))(3) (P(3)P(3)(tBu), 3) are reported, along with the synthesis and characterization of ruthenium chloro complexes RuCl(2)(P(2)P(3)(tBu)) (4), RuCl(2)(PhP(2)P(2)(tBu)) (5), and RuCl(2)(P(3)P(3)(tBu)) (6). The bulky P(2)P(3)(tBu) (1) and P(3)P(3)(tBu) (3) ligands are the most sterically encumbered PP(3)-type ligands so far synthesized, and in all cases, only three phosphorus donors are able to bind to the metal center. Complexes RuCl(2)(PhP(2)P(2)(tBu)) (5) and RuCl(2)(P(3)P(3)(tBu)) (6) were characterized by crystallography. Low temperature solution and solid state (31)P{(1)H} NMR were used to demonstrate that the structure of RuCl(2)(P(2)P(3)(tBu)) (4) is probably analogous to that of RuCl(2)(PhP(2)P(2)(tBu)) (5) which had been structurally characterized.     

Dative sigma- and pi-bonding in boron-nitrogen compounds: molecular structures of (CH3)2NB(CH3)N(CH3)B(CH3)2 and [(CH3)2B]2NN(CH3)2 determined by gas electron diffraction and quantum chemical calculations

The molecular structures of dimethylamino[(dimethylboryl)methylamino]methylborane, Me2NBMeNMeBMe2 (1) and 1,1-bis(dimethylboryl)-2,2-dimethylhydrazine, (Me2B)2NNMe2 (2) have been determined by gas electron diffraction (GED), density functional theory calculations at the B3PW91/6-311++G** level and ab initio calculations at the MP2/6-311++G** level. 1 adopts an open structure similar to that of the isoelectronic hydrocarbon molecule permethylbutadiene; the central B-N bond distance at 148.0/149.3(7) pm (MP2/GED) corresponds to a single covalent N--B bond distance, the two terminal distances, 140.9/140.5(4) pm and 141.8/141.3(4) pm, correspond to the distance between N and B atoms joined by a covalent sigma-bond and a dative pi-bond. A closed form where the establishment of a dative bond between the terminal N and B atoms has led to the formation of a four-membered ring also corresponds to a minimum on the potential energy surface, but the energy is calculated to be 14.3 kJ mol(-1) higher at the MP2 level. This structure is also incompatible with the GED data. 2 adopts a structure in which a dative sigma-bond between the dimethylamino N atom and one of the boron atoms has led to the formation of a three-membered N(2)B ring. The dative sigma-bond distance is 165.5/164.0(13) pm, the two other bond distances in the ring are N-B=150.6/148.9(9) pm corresponding to a covalent sigma-bond and N-N=145.1/145.4(3) pm. The terminal B--N distance 139.6/138.9(9) pm is consistent with a covalent sigma-bond augmented by a dative pi-bond. An open Y-shaped structure also corresponds to a minimum on the potential energy surface, but the energy is 18.7 kJ mol(-1) higher (MP2) and it is incompatible with the GED data.     

Self-assembly of the octanuclear cluster [Cu8(OH)10(NH2(CH2)2CH3)12]6+ and the one-dimensional N-propylcarbamate-linked coordination polymer {[Cu(O2CNH(CH2)2CH3)(NH2(CH2)2CH3)3](ClO4)}n

The reaction of Cu(ClO4)2.6-H2O and n-propylamine in methanol gives two high-nuclearity products of well-defined compositions. At amine concentrations greater than seven equivalents compared to copper ion concentration, the system fixes carbon dioxide from air to form the one-dimensional carbamate-bridged coordination polymer, {[Cu(mu2-O,O'-O2CNH(CH2)2CH3)(NH2(CH2)2CH3)3](ClO4)}n ({1-ClO4}n). Lower relative amine concentrations lead to the self-assembly of an octanuclear copper-amine-hydroxide cluster [Cu8(OH)10(NH2(CH2)2CH3)12]6+ (2). Both compounds exhibit unique structures: {1-ClO4}n is the first mu2-O,O'-mono-N-alkylcarbamate-linked coordination polymer and 2 is the largest copper-hydroxide-monodentate amine cluster identified to date. The crystal structures indicate that the size of the n-propyl group is probably crucial for directing the formation of these compounds. Magnetic susceptibility studies indicate very weak antiferromagnetic coupling for 1. The octanuclear cluster 2 displays slightly stronger net antiferromagnetic coupling, despite the presence of a number of Cu-O(H)-Cu angles below the value of about 97 degrees that would normally be expected to yield ferromagnetic coupling.     

Interpretation der Schwingungsspektren von (CH3)2SO2, (CH3)2SO(NH) und (CH3)2S(NH)2 unter Verwendung eines Kopplungsstufenverfahrens

Normal Coordinate Analysis of (CH₃)₂SO₂, (CH₃)₂SO(NH), and (CH₃)₂S(NH)₂ using the Method of Stepwise Coupling The qualitative assignment of the vibrational spectra of (CH₃)₂SO₂ ( 1 ), (CH₃)₂SO(NH) ( 2 a ), and (CH₃)₂S(NH)₂ ( 3 a ) and of the C and N deuterated derivatives of 2 a and 3 a is used in a normal coordinate analysis by the method of stepwise coupling. The force constants and the energy distributions are calculated in symmetry coordinates using a generalized valence force field.     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP(N(CH3)2)3 – OP(CH3)3 und SP(N(CH3)2)3 – SP(CH3)3

Vibrational Spectra and Force Constants of the Series OP(N(CH₃)₂)₃ – OP(CH₃)₃ and SP(N(CH₃)₂)₃ – SP(CH₃)₃ The vibrational spectra (IR and Raman) of the compounds of the title series are recorded and assigned to the normal vibrations. By a simplified force field the valence force constants are calculated and discussed. The results are compared with those of the NMR spectroscopy.     

A Tri-Coordinate-Magnesium Silylamide Complex: {[(CH3)3Si]2N}2MgO(CH2CH2)2OMg{N[Si(CH3)3]2}2

The reaction of diethylmagnesium dioxane adduct solution with 1,1,1,3,3,3-hexamethyldisilazan ((CH₃)₃SiNHSi(CH₃)₃) gives {[(CH₃)₃Si]₂N}₂MgO(CH₂CH₂)₂OMg{N[Si(CH₃)₃]₂}₂ (1); this alkoxomagnesium silylamide in the solid state contains unprecedented three-coordinate magnesium and oxygen atoms.     

Schwingungsspektren und Kraftkonstanten von Cl3SiP(CH3)2 und Cl3SiAs(CH3)2

Vibrational Spectra and Force Constants of Cl₃SiP(CH₃)₂ and Cl₃SiAs (CH₃)₂ The i.r. and Raman spectra of Cl₃SiP(CH₃)₂ and Cl₃SiAs (CH₃)₂ have been recorded and assigned. A normal coordinate analysis has been made using a modified valence force field. The SiP force constant is slightly higher than those of alkylsilylphosphines, whereas a similar effect is not found for the SiAs bond.     

Darstellung und Schwingungsspektren von F3SiAs(CH3)2 und F3SiP(CH3)2

Inhaltsübersicht. Verschiedene Methoden zur Darstellung von F₃SiAs(CH₃)₂ und F₃SiP(CH₃)₂ werden mitgeteilt und diskutiert. Die neuen Trifluorsilylverbindungen werden durch KMR- und IR-Spektren sowie durch Umsetzung mit polaren Reaktanden charakterisiert, Die Schwingungsspektren des F₃SiAs(CH₃)₂ werden mit Hilfe einer Normalkoordinatenanalyse näher untersucht. Preparation and Vibrational Spectra of F₃SiAs (CH₃)₂ and F₃SiP(CH₃)₂ Various preparative routes for the synthesis of F₃SiAs(CH₃)₂ and F₃SiP(CH₃)₂ are discussed. The new trifluoro-silyl compounds are characterized by n.m.r. and i.r. spectra as well as by the reaction with polar compounds. The vibrational spectra of F₃SiAs(CH₃)₂ are investigated using a normal coordinate analysis.     

双核有机锡(Ⅳ)配合物[Ph_3Sn(CH_3OH)O_2CC_6H_4CO_2(CH_3OH)-SnPh_3]·2CH_3OH和[Ph_3SnS_2CN(CH_2CH_2)_2NCS_2SnPh_3]·2CH_3OH的合成、表征和晶体结构

利用三苯基氯化锡和对苯二甲酸二钠、哌嗪荒酸二钠在甲醇中反应 ,合成了双核有机锡 (Ⅳ )配合物 [Ph3 Sn (CH3 OH)O2 CC6H4 CO2 (CH3 OH)SnPh3 ]·2CH3 OH (1)和 [Ph3 SnS2 CN(CH2 CH2 ) 2 NCS2 SnPh3 ]·2CH3 OH (2 ) .通过元素分析、红外光谱和核磁共振氢谱对其结构进行了表征 .用X射线单晶衍射测定了这两个化合物的晶体结构 .化合物 1为单斜晶系 ,空间群P2 1/n ,a =1.5 199(5 )nm ,b =0 .90 0 0 (3)nm ,c =1.82 0 6 (6 )nm ,β =113.970 (5 )° ,Z =2 ,V =2 .2 75 5(13)nm3 ,Dc=1.413g/cm3 ,μ =1.146mm-1,F(0 0 0 ) =980 ,R1=0 .0 35 3,wR2 =0 .0 6 0 6 .化合物 2为单斜晶系 ,空间群P2 1/c,a =1.5 0 6 6 (5 )nm ,b =1.0 875 (4 )nm ,c =1.35 42 (5 )nm ,β =91.6 14(5 )°,Z =2 ,V =2 .2 178(14)nm3 ,Dc=1.498g/cm3 ,μ =1.35 1mm-1,F(0 0 0 ) =10 0 8,R1=0 .0 40 1,wR2 =0 .1148.在 1和 2的晶体中 ,锡原子呈五配位畸变三角双锥构型 .配合物 1由未配位的甲醇分子通过氢键作用形成二维网状结构     

Zur solvensfreien Darstellung von Tetramethylammoniumsalzen: Synthese und Charakterisierung von [N(CH3)4]2[C2O4], [N(CH3)4][CO3(CH3)], [N(CH3)4][NO2], [N(CH3)4][CO2H] und [N(CH3)4][O2C(CH2)2CO2(CH3)]

Solvent-free Synthesis of Tetramethylammonium Salts: Synthesis and Characterization of [N(CH₃)₄]₂[C₂O₄], [N(CH₃)₄][CO₃CH₃], [N(CH₃)₄][NO₂], [N(CH₃)₄][CO₂H], and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] A general procedure to synthesize tetramethylammonium salts is presented. Several tetramethylammonium salts were prepared in a crystalline state by solvent-free reaction of trimethylamine and different methyl compounds at mild conditions: [N(CH₃)₄]₂[C₂O₄] (cubic; a = 1 114.8(3) pm), [N(CH₃)₄][CO₃CH₃] (P2₁/n; a = 813.64(3), b = 953.36(3), c = 1 131.3(4) pm, β = 90.03(1)°), [N(CH₃)₄][NO₂] (Pmmn; a = 821.2(4), b = 746.5(3), c = 551.5(2) pm), [N(CH₃)₄][CO₂H] (Pmmn; a = 792.8(7), b = 791.7(3), c = 563.3(4) pm) and [N(CH₃)₄][O₂C(CH₂)₂CO₂CH₃] (P2₁; a = 731.1(2), b = 826.4(3), c = 1 025.2(3) pm, β = 110.1(1)°). The tetramethylammonium salts were characterized by IR-spectroscopy and X-ray diffraction. The crystal structures of the methylcarbonate and the nitrite are described.     

Vanadium complexes of the N(CH2CH2S)3(3-) and O(CH2CH2S)2(2-) ligands with coligands relevant to nitrogen fixation processes

Vanadium(III) and vanadium(V) complexes derived from the tris(2-thiolatoethyl)amine ligand [(NS3)3-] and the bis(2-thiolatoethyl)ether ligand [(OS2)2-] have been synthesized with the aim of investigating the potential of these vanadium sites to bind dinitrogen and activate its reduction. Evidence is presented for the transient existence of (V(NS3)(N2)V(NS3), and a series of mononuclear complexes containing hydrazine, hydrazide, imide, ammine, organic cyanide, and isocyanide ligands has been prepared and the chemistry of these complexes investigated. [V(NS3)O] (1) reacts with an excess of N2H4 to give, probably via the intermediates (V(NS3)(NNH2) (2a) and (V(NS3)(N2)V(NS3) (3), the V(III) adduct [V(NS3)(N2H4)] (4). If 1 is treated with 0.5 mol of N2H4, 0.5 mol of N2 is evolved and green, insoluble [(V(NS3))n] (5) results. Compound 4 is converted by disproportionation to [V(NS3)(NH3)] (6), but 4 does not act as a catalyst for disproportionation of N2H4 nor does it act as a catalyst for its reduction by Zn/HOC6H3Pri2-2,6. Compound 1 reacts with NR1(2)NR2(2) (R1 = H or SiMe3; R2(2) = Me2, MePh, or HPh) to give the hydrazide complexes [V(NS3)(NNR2(2)] (R2(2) = Me2, 2b; R2(2) = MePh, 2c; R2(2) = HPh, 2d), which are not protonated by anhydrous HBr nor are they reduced by Zn/HOC6H3Pri2-2,6. Compound 2b can also be prepared by reaction of [V(NNMe2)(dipp)3] (dipp = OC6H3Pri2-2,6) with NS3H3. N2H4 is displaced quantitatively from 4 by anions to give the salts [NR3(4)][V(NS3)X] (X = Cl, R3 = Et, 7a; X = Cl, R3 = Ph, 7b; X = Br, R3 = Et, 7c; X = N3, R3 = Bu(n), 7d; X = N3, R3 = Et, 7e; X = CN, R3 = Et, 7f). Compound 6 loses NH3 thermally to give 5, which can also be prepared from [VCl3(THF)3] and NS3H3/LiBun. Displacement of NH3 from 6 by ligands L gives the adducts [V(NS3)(L)] (L = MeCN, nu CN 2264 cm-1, 8a; L = ButNC, nu NC 2173 cm-1, 8b; L = C6H11NC, nu NC 2173 cm-1, 8c). Reaction of 4 with N3SiMe3 gives [V(NS3)(NSiMe3)] (9), which is converted to [V(NS3)(NH)] (10) by hydrolysis and to [V(NS3)(NCPh3)] (11) by reaction with ClCPh3. Compound 10 is converted into 1 by [NMe4]OH and to [V(NS3)NLi(THF)2] (12) by LiNPri in THF. A further range of imido complexes [V(NS3)(NR4)] (R4 = C6H4Y-4 where Y = H (13a), OMe (13b), Me (13c), Cl (13d), Br (13e), NO2 (13f); R4 = C6H4Y-3, where Y = OMe (13g); Cl (13h); R4 = C6H3Y2-3,4, where Y = Me (13i); Cl (13j); R4 = C6H11 (13k)) has been prepared by reaction of 1 with R4NCO. The precursor complex [V(OS2)O(dipp)] (14) [OS2(2-) = O(CH2CH2S)2(2-)] has been prepared from [VO(OPri)3], Hdipp, and OS2H2. It reacts with NH2NMe2 to give [V(OS2)(NNMe2)(dipp)] (15) and with N3SiMe3 to give [V(OS2)(NSiMe3)(dipp)] (16). A second oxide precursor, formulated as [V(OS2)1.5O] (17), has also been obtained, and it reacts with SiMe3NHNMe2 to give [V(OS2)(NNMe2)(OSiMe3)] (18). The X-ray crystal structures of the complexes 2b, 2c, 4, 6, 7a, 8a, 9, 10, 13d, 14, 15, 16, and 18 have been determined, and the 51V NMR and other spectroscopic parameters of the complexes are discussed in terms of electronic effects.     

Synthese und Kristallstruktur von Praseodympropionat-trihydrat,Pr(CH3CH2COO)3(H2O)3

Synthesis and Crystal Structure of Praseodymium Propionate Trihydrate, Pr(CH₃CH₂COO)₃(H₂O)₃ Single crystals of Pr(CH₃CH₂COO)₃(H₂O)₃ were obtained by dissolving freshly prepared praseodymium hydroxide in diluted propionic acid. The crystal structure (monoclinic, P2₁/c, Z = 4, a = 1034.2(2) pm, b = 1521.2(3) pm, c = 2086.3(7) pm, β = 102.87(2)°, R1 = 0.0864, wR2 = 0.1196) consists of one-dimensional infinite chains parallel [010]. Pr1 and Pr2 are coordinated by four tridentate-bridging propionate groups. Additionally, Pr1 is coordinated by three “coordination water” molecules, Pr2 by two bidentate propionate groups. There are, in addition, three “crystal water” molecules so that praseodymium propionate trihydrate should be formulated as [(H₂O)₃Pr1(CH₃CH₂COO)₄Pr2(CH₃CH₂COO)₂] (H₂O)₃.     

Mass spectra of polymeric thioformaldehydes (CH2S)3, (CH2S)4, (CH2S)5 and (CH2S)x

The mass spectral fragmentations of various thioformaldehydes, 1,3,5-trithiacyclohexane, 1,3,5,7-tetrathiacyclooctane, 1,3,5,7,9-pentathiacyclodecane and a polymeric form (CH₂S)_x have been examined. The principal features of the spectra are reported. The fragmentation occurred by fracture of the ring in the cyclic compounds with or without rearrangement.