共查询到20条相似文献,搜索用时 15 毫秒
1.
The 6‐aza‐nido‐decaboranes RNB9H11 ( 1a—d ; R = H, Ph, 4‐C6H4Me, 4‐C6H4Cl) act as 1, 2‐hydroboration agents via their 9‐BH vertex, giving products RNB9H10R′. The boranes 1a, b and 3‐hexyne yield the 9‐(1‐ethyl‐1‐butenyl)‐6‐aza‐nido‐decaboranes 2a, b (R′ = CEt = CHEt). 2, 3‐Dimethyl‐2‐butene is hydroborated by 1a—d under formation of the 9‐(1, 1, 2‐trimethylpropyl)‐6‐aza‐nido‐decaboranes 3a—d (R′ = —CMe2 —CHMe2). With the boranes 1a—c and (trimethylsilyl)ethene, a 85:15 mixture of the products (RNB9H10)CH2CH2(SiMe3)( 4a—c ) and their chiral isomers (RNB9H10)CH(SiMe3)CH3 ( 5a—c ) is obtained. The action of BH3(SMe2) on the mixtures 4b/5b or 4c/5c results in a closure of the nido‐NB9 skeleton of 4b or 4c , respectively, with a closo‐NB11 skeleton of the products RNB11H10R′ ( 6b or 6c;R′ = CH2CH2(SiMe3)); R′ is found in position 7 of 6b, c . All products of the type 2—6 are characterised by NMR. 相似文献
2.
The Lewis base SMe2 in 7‐B11H13(SMe2) ( 1a ) can be replaced by the amines L = NH2(CH2tBu), NH2Cy, NH2Ph, NH2(4‐C6H4Me), py, chinoline or the phosphanes L = PPh3, PMePh2, yielding 7‐B11H13L ( 1b ‐ i ). The borane 1a can be deprotonated by certain amines, alkanides, or hydrides to give the anion 7‐B11H12(SMe2)‐ ( 2a ). Replacing the base SMe2 in the anion 2a by weak bases gives B11H12L‐ (L = PPh3, MeCN; 2h , j ). Upon reaction of 1a with the amine NH2(CH2tBu) in the ratio 1:2, a deprotonation and the substitution of SMe2 by the amine are observed, 7‐B11H12[NH2(CH2tBu)]‐ ( 2b ) being formed. At 170 °C, the 7‐isomers 1b , f are isomerized into a mixture of the corresponding 1‐ and 2‐isomers ( 1b′ , f′ and 1b″ , f″ , respectively). 相似文献
3.
The closo‐undecaborate A2[B11H11] (A = NBzlEt3) can be halogenated with excess N‐chlorosuccine imide, bromine or iodine, respectively, to give the perhalo‐closo‐undecaborates A2[B11Hal11] (Hal = Cl, Br, I). The chlorination in the 11 : 1 ratio of the reagents yields A2[B11HCl10], whose subsequent iodination makes A2[B11Cl10I] available. The three type [B11Hal11]2– anions show only one and the two type [B11Cl10X]2– anions (X = H, I) only two 11B NMR peaks in the ratio 10 : 1, thus exhibiting the same degenerate rearrangement of the octadecahedral B11 skeleton as is well‐known for [B11H11]2–. The crystal structure analysis of A2[B11Br11] and A2[B11I11] reveals a rigid octadecahedral skeleton in the solid state, up to 330 K, whose B–B bond lengths deviate more or less from the idealized C2v gas phase structure, but are in good accordance with the distances of A2[B11H11]. Electrochemical experiments elucidate the mechanism of the known oxidation of [B11H11]2– to give [B22H22]2–: A first one‐electron transfer is followed by the dimerization of the [B11H11]– monoanion, whereas neutral B11H11, a presumably most reactive species, does not play a role as an intermediate. The electrochemical oxidation of [B11Hal11]2– anions also starts with a one‐electron transfer, which is perfectly reversible only in the case of Hal = Br. There is no electrochemical indication for the formation of [B22Hal22]2–. The neutral species B11Hal11 should be a short‐lived, very reactive species. 相似文献
4.
5.
The closo‐dodecaborate [B12H12]2? is degraded at room temperature by oxygen in an acidic aqueous solution in the course of several weeks to give B(OH)3. The degradation is induced by Ag2+ ions, generated from Ag+ by the action of H2S2O8. Oxa‐nido‐dodecaborate(1?) is an intermediate anion, that can be separated from the reaction mixture as [NBzlEt3][OB11H12] after five days in a yield of 18 %. The action of FeCl3 on the closo‐undecaborate [B11H11]2? in an aqueous solution gives either [B22H22]2? (by fusion) or nido‐B11H13(OH)? (by protonation and hydration), depending on the concentration of FeCl3. In acetonitrile, however, [B11H11]2? is transformed into [OB11H12]? by Fe3+ and oxygen. The radical anions [B12H12] ˙ ? and [B11H11] ˙ ? are assumed to be the primary products of the oxidation with the one‐electron oxidants Ag2+ and Fe3+, respectively. These radical anions are subsequently transformed into [OB11H12]? by oxygen. The crystal structure analysis shows that the structure of [OB11H12]? is derived from the hypothetical closo‐oxaborane OB12H12 by removal of the B3 vertex, leaving a non‐planar pentagonal aperture with a three‐coordinate O vertex, as predicted by NMR spectra and theory. 相似文献
6.
Systematic studies on selenoborates containing a B12 cluster entity and alkali metal cations led to the new crystalline phase Na6[B18Se17] which consists of a icosahedral B12 cluster completely saturated with trigonal‐planar BSe3 units and sodium counter‐ions. Neighbouring cluster entities are connected in one direction via exocyclic selenium atoms forming the infinite chain anion ([B18Se16Se2/2]6–)∞. The new chalcogenoborate was prepared in a solid state reaction from sodium selenide, amorphous boron and selenium in evacuated carbon coated silica tubes at a temperature of 850 °C. Na6[B18Se17] crystallizes in the monoclinic space group C2/c (no. 15) with a = 18.005(4) Å, b = 16.549(3) Å, c = 11.245(2) Å, β = 91.35(3)° and Z = 4. 相似文献
7.
The potassium salt of the [1‐H2N‐2‐F‐closo‐1‐CB11H10]– anion ( 1 ) was obtained from an insertion reaction of Li3[7‐H2N‐nido‐7‐CB10H10] with BF3 · OEt2. Anion 1 was protonated to the neutral species 1‐H3N‐2‐F‐closo‐1‐CB11H10 (H 1 ) and it was iodinated with ICl to the [1‐H2N‐2‐F‐closo‐1‐CB11I10]– anion ( 2 ). All species were characterized by multinuclear NMR, IR, and Raman spectroscopy as well as by elemental analysis. The structure of H 1· (CH3)2CO was studied by single‐crystal X‐ray diffraction and the experimentally determined bond lengths are compared to values derived from density functional calculations. 相似文献
8.
DFT‐calculations of the geometries of the closo‐anion [B11H11]2– in its ground state and in the transition state of its skeletal rearrangement and of the protonated species [B11H12]– in its ground state were performed at the B3LYP/6‐31++G(d,p) level. The corresponding NMR shifts were computed on the basis of the optimized geometry by the GIAO method at the same level. Calculated and observed NMR data are in good agreement and thus prove the structure of [B11H12]–, previously deduced from 2 D‐NMR spectra. The addition of water, ethanol, and pyridine to [B11H12]– at low temperature gave the nido‐species [B11H13(OH)]–, [B11H13(OEt)]–, and [B11H12(py)]–, respectively. The structures of these anions were investigated by NMR methods and the last two of them by crystal structure analyses of appropriate salts. The course of the addition reactions can be rationalized on the basis of the structurally characterized reaction components. 相似文献
9.
Srinivasan Natarajan Wilhelm Klein Martin Panthfer Leo van Wüllen Martin Jansen 《无机化学与普通化学杂志》2003,629(6):959-962
A room temperature reaction of zinc acetate, tributyl borate and N, N, N′N′‐tetramethylethylenediamine (tmen) in a mixture of water and 1‐butanol has given rise to a new bis‐(hexaborato)‐zincate, [(Me)2NH(CH2)2NH(Me)2][{Zn(B6O7(OH)6}2]·2H2O ( I ). The structure, determined by single crystal X‐ray diffraction, (P1, a = 8.3014(2), b = 9.2489(2), c = 10.442(2)Å, α = 107.71(3), β = 94.22(3), γ = 100.02(3)°, V = 749.6(3)Å3 = Z = 1, R1 = 0.0387, wR2 = 0.105), consists of anionic molecular Zn hexaborate units forming a herringbone arrangement, through strong hydrogen bond interactions, with the amine molecule situated between the chains. Compound I is the first bis‐(hexaborato)‐zincate, to our knowledge, that has been synthesized in the presence of an organic amine. 相似文献
10.
The concept of orbital compatibility is used to explain the relative energies of different macropolyhedral structural patterns such as closo‐closo, closo‐nido, and nido‐nido. A large polyhedral borane condenses preferentially with a smaller polyhedron owing to orbital compatibility. Calculations carried out at the B3LYP/6‐31G* level show that the macropolyhedron closo(12)‐closo(6) is the most preferred structural pattern among the face‐sharing closo‐closo systems. The relative stabilities of four‐shared‐atom closo‐closo, three‐shared‐atom closo‐closo, three‐shared‐atom closo‐nido, edge‐sharing closo‐nido, and edge‐sharing nido‐nido structures are in accordance with the difference in the number of vertices of the individual polyhedra of the macropolyhedra. When the difference in the number of vertices of the individual polyhedra is large, the stability of the macropolyhedra is also large. Calculations further show that the orbital compatibility plays an important role in deciding the stability of the macropolyhedral boranes with more than two polyhedral units. The dependence of the orbital compatibility on the relative stability of the macropolyhedron varies with other factors such as inherent stability of the individual polyhedron and steric factors. 相似文献
11.
Karl E. Bessler Elisabeth B. Dourado Myller de S. Carvalho Sebastio S. Lemos Javier Ellena 《无机化学与普通化学杂志》2005,631(10):1935-1940
A convenient method for the preparation of diphenylboron chelates from ammonium tetraphenylborate is described. A variety of five‐ or six‐membered O,O‐, N,O‐ and N,N‐chelates were obtained in yields from 60 to 90 %. The isolated compounds were characterized by elemental analysis, IR spectroscopy and multinuclear magnetic resonance spectroscopy (1H, 13C, and 11B). The crystal and molecular structures of (pyridine‐2‐acetyloximato)diphenylboron and (1‐phenylazo‐2‐naphtholato)diphenylboron were determined by X‐ray diffraction on single crystals. 相似文献
12.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
13.
The one‐pot condensation/coordination reaction of 4‐iodobenzoylchloride, 2,3,4‐trimethylpyrrole and BF3 × Et2O yields the BF2 chelate complexes of the 1:1 condensation product 2‐(4‐iodobenzoyl)‐3,4,5‐trimethylpyrrole and of the 1:2 product 6‐(4‐iodophenyl)‐2,3,4,8,9,10‐hexamethyldipyrrin, as separable compounds in 6 and 38 % yield, respectively. Both new boron derivatives are fluorescent already upon exitation with ambient light. While the fluorescence quantum yield of the benzoyl derivative is very low, this value is significantly higher for the related boron dipyrrin (BODIPY) derivative. Single crystal X‐ray diffraction studies of both compounds reveal that the reason for these deviating physical properties are structural in nature. For the BODIPY an essentially flat structure of the fluorophor has been established, in addition to restricted rotation of the 4‐iodophenyl substituent, so that no conformational dynamic facilitates radiationless deactivations. The 1:1 condensation product on the other hand allows a fast equilibration of the photophysical exitation by dynamic processes and therefore exhibits a low fluorescence quantum yield. Both luminophores contain an iodoaryl moiety with potential uses for further functionalization and bioconjugation. 相似文献
14.
15.
Christian Hoberg Melanie Gldner Ursula Cornelissen Heiner Homborg 《无机化学与普通化学杂志》2000,626(12):2435-2437
μ‐Phthalocyaninato‐bis({triphenylphosphine oxide}sodium): Synthesis and Crystal Structure Blue μ‐phthalocyaninato‐bis({triphenylphosphine oxide}sodium) ( 1 ) is prepared by heating triphenylphosphine oxide with disodium phthalocyaninate at 160 °C. 1 is centrosymmetric (space group P1). The Na atom is located in a tetragonal pyramid co‐ordinating four isoindole N atoms at a distance varying between 2.409(2) and 2.438(2) Å, and one O atom at 2.198(2) Å. The Na–Na distance is 2.823(5) Å, and the Na–O–P angle is 145.5(1)°. 相似文献
16.
17.
N‐sulfinylacylamides R‐C(=O)‐N=S=O react with (CF3)2BNMe2 ( 1 ) to form, by [2+4] cycloaddition, six‐membered rings cyclo‐(CF3)2B‐NMe2‐S(=O)‐N=C(R)‐O for R = Me ( 2 ), t‐Bu ( 3 ), C6H5 ( 4 ), and p‐CH3C6H4 ( 5 ) while N‐sulfinylcarbamic acid esters R‐O‐C(=O)‐N=S=O react with 1 to yield mixtures of six‐membered (cyclo‐(CF3)2B‐NMe2‐S(=O)‐N=C(OR)‐O) and four‐membered rings (cyclo‐(CF3)2B‐NMe2‐S(=O)‐N(C=O)OR) for R = Me ( 6 and 9 ), Et ( 7 and 10 ), and C6H5 ( 8 and 11 ). The structure of 5 has been determined by X‐ray diffraction. 相似文献
18.
Jürgen Buschmann Dieter Lentz Peter Luger Genivaldo Perpetuo Dagmar Preugschat Joseph S. Thrasher Helge Willner Hans‐Jrg Wlk 《无机化学与普通化学杂志》2004,630(7):1136-1142
A new method for the synthesis of the unstable pentafluorosulfanyl isocyanide from N‐(pentafluorosulfanyl)(dichloromethanimine) was developed, thereby allowing for the study of its spectroscopic data. The structure of pentafluorosulfanyl isocyanide was determined by X‐ray crystallography at 113 K. The molecule possesses an almost linear S‐N‐C arrangement and an unexpectedly long S‐N bond. In addition, the structures of pentafluorosulfanyl cyanide, pentafluorosulfanyl isocyanate, pentafluorosulfanyl isothiocyanate, and N‐(pentafluorosulfanyl)(dichloro)methanimine were determined by single crystal X‐ray crystallography at low temperatures. 相似文献
19.
[Fc2B2(Br)(μ‐NPEt3)2]+Br– – a Ferrocenyl‐substituted Phosphoraneiminato Complex of Boron [Fc2B2(Br)(μ‐NPEt3)2]+Br– has been prepared from ferrocenylboron dibromide, [Fe(η5‐C5H5)(η5‐C5H4BBr2)], and the silylated phosphoraneimine Me3SiNPEt3 in dichloromethane solution to give orange‐red single crystals which were characterized by IR, NMR and 57Fe Mössbauer spectra, as well as by a crystal structure determination. [Fc2B2(Br)(μ‐NPEt3)2]+Br– · 3 CH2Cl2 ( 1 · 3 CH2Cl2): Space group P21/n, Z = 4, lattice dimensions at –50 °C: a = 1370.6(3), b = 2320.9(5), c = 1454.4(2), β = 95.38(1)°, R1 = 0.061. In the cation of 1 the ferrocenyl‐substituted boron atoms are connected by the nitrogen atoms of the [NPEt3]– groups to form a planar B2N2 four‐membered ring. One of the boron atoms having planar, the other tetrahedral coordination. 相似文献
20.
Stanna‐closo‐dodecaborate [Bu3MeN]2[SnB11H11] reacts as a nucleophile with the rhodium and iridium electrophiles of type [Cp*M(bipy′)Cl][BF4] under formation of a transition metal tin bond. The zwitterionic molecules [Cp*M(bipy′)(SnB11H11)] (with M = Rh, Ir) were characterized by NMR spectroscopy, elemental analyses and X‐ray crystal structure analyses. A high dipole moment of 25.67 D was calculated by DFT methods in the case of the rhodium derivative. 相似文献