共查询到20条相似文献,搜索用时 31 毫秒
1.
Synthesis and Characterization of Tungsten Complexes with ER?-Ligands, E = O, S, Se, Te; R = Alkyl, Aryl The reaction of η7-C7H7W(CO)2I with ER? bases yielded several types of compounds, η7-C7H7W(CO)2ER, η3-C7H7(CO)2W(μ-OR)3W(CO)2-η4-C7H8, (CO)4W(μ-ER)2W(CO)4, η7-C7H7W(μ-ER)3W(CO)3 and η7-C7H7W(μ-ER)3W(CO)(μ-ER)2W(CO)4. The compounds were characterized by elementary analysis and their spectroscopie data. The structures of typical representatives of every class of compounds were confirmed by X-ray structure analysis. 相似文献
2.
The Phosphides LiR2P7, Li2RP7 (R = Me3Si, Et, iPr, iBu) as well as Mixed Alkylated and Silylated Heptaphosphanes(3) Formation and properties of LiR2P7 and Li2PR7 (R = Me3Si, Et, iPr, iBu) and their reactions with Me3SiCl or alkylhalides yielding mixed alkylated and silylated heptaphosphanes(3) are reported. Reactions of (Me3Si)3P7 and Li3P7. 3 DME produce mixtures of Li(Me3Si)3P7, Li2(Me3Si)P7 and Li3P7 from which pure Li(Me3Si)2P7 (s, as) can be isolated by means of an extraction with toluene. Similarly, the isomers of LiR2P7 (R = Et, iPr, iBu) can be extracted from the mixtures obtained by reacting Li3P7 with alkylbromides. The (s) isomers of LiR2P7 in solution at about 20°C from the (as) isomers whereas the latter up to 70°C do not show any inversion. The (as) lithiumdialkylphosphides can be obtained as ether free products (red brown powder, isoluble in toluene, soluble in THF) by repeated addition of toluene and removal of the solvents; the (s) isomers decompose during the procure. In reactions of LiEt2P7. THF (s, as) in toluene at ?30°C with EtBr only the (s) isomer is substituted and gives Et3P7 (s), however on warming to 20°C by inversion of Pe a ratio of (s) : (as( = 1 : 3 is obtained. With Li(iBu)2P7, (s) reaction begins above ?20°C the giving both the (s) and the (as) isomer. (iBu)3P7 (s) is the prefered isomer at higher temperatures. Li(Me3Si)2P7 (s, as) with Me3SiCl exclusively yields (Me3Si)3P7 (s). Li2RP7 (R = alkyl, Me3SI) is not available. From mixtures with LiR2P7 and Li3P7, it can be isolated only after repeated cumbersome extraction of LiR2P7 as was shown with Li2(iPr)P7 as an example. Ether free LiEt2P7(s, as) with Me3SiCl exclusively gives Et2(Me3Si)P7 (s, as) whereas LiEt2P7 ? THF due to its THF content does not. Similarly, ether free Li(iBu)2P7 yields (iBu)2(Me3Si)P7 (s, as). The compounds R(Me3Si)2P7 (R = alkyl) cannot be selectively prepared neither starting from Li2RP7 with Me3SiCI) nor from Li(Me3Si)2P7 with RX. Such, the reaction of Li(Me3Si)2P7 ? THF with EtBr in toluene at ?78°C yield a mixture of Et(Me3Si)2P7 (42%), Et2(Me3Si)P7 (27010), (Me3Si)3P7 (29%) and Et3P7 (2%). (Me3Si)3P7 with MeI in a molar ratio of 1 : 1 at 70°C quantitatively produces Me(Me3Si)2P7 whereas already using a molar ratio of 1 : 2 also Me3P7 is obtained. With EtBr mixtures of Et(Me3Si)2P7 and Et3P7 are formed. iBuBr gives iBu3P7, but tBuBr does not yield any tBu3P7. 相似文献
3.
Reactions of the Cycloheptatrienyl Complexes [η7-C7H7W(CO)3]BF4 and η7-C7H7Mo(CO)2Br with Neutral Ligands and the Electrochemical Reduction of the Wolfram Complex Compounds of the type [η7-C7H7M(CO)2L][BF4] (L = P(C6H5)3, As(C6H5)3, Sb(C6H5)3 for M = W and L = N2H4 for M = Mo) were synthesized and characterisized. The iodide η7-C7H7W(CO)2I reacts with the diphosphine ((C6H5)2PCH2)2 to give the trihapto complex η3-C7H7 W(CO)2I((C6H5)2PCH2)2. In the case of η7-C7H7Mo(CO)2 Br reaction with hydrazine leads to the substitution product [η7-C7H7 Mo(CO)2N2H4]⊕, which can be stabilized by large anions. The binuclear complex [C7H7W(CO)3]2 has been synthesized electrochemically. 相似文献
4.
《Journal of organometallic chemistry》1986,302(3):371-377
Reaction of [WI(CO)2(η7-C7H7)] with dppm (dppm = Ph2PCH2PPh2) or dppe (dppe = Ph2PCH2CH2PPh2) gives the trihaptocycloheptatrienyl complexes [WI(CO)2(L-L)(η3-C7H7)] [L-L = dppm, (A1); L-L = dppe (A2)]. The complex A1 reacts with NH4PF6 to give the unidentate biphosphine complex [W(CO)2(dppm-P)(η7-C7H7)][PF6] (B) which yields [W(CO)(dppm)(η7-C7H7)][PF6] (C) on reaction with Me3NO·2H2O. Substitution of a carbonyl ligand in [W(CO)3(η7-C7H7)][PF6] with the organometallic phosphine ligand [Mo(CO)2(dppe-P)(η7-C7H7)][PF6] yields the heterobimetallic [{W(CO)2(η7-C7H7)}(μ-dppe){Mo(CO)2(η7-C7H7)}x][PF6]2 (D). 相似文献
5.
The photo‐induced substitution of a CO ligand has been used to prepare the halfsandwich complexes (η3‐C3H5)V(CO)4[P(C7H7)3] ( 1 ), (η5‐C5H5)V(CO)3[P(C7H7)3] ( 2 ), (η7‐C7H7)V(CO)2[P(C7H7)3] ( 3 ), (η6‐C6H3Me3)Cr(CO)2[P(C7H7)3] ( 4 ), and (η5‐C5H5)Mn(CO)2[P(C7H7)3] ( 7 ), in which the olefinic phosphane is coordinated as a conventional two‐electron ligand through the lone pair of electrons at phosphorus. Some analogues, which are permethylated at the aromatic ring ( 2* , 4* , 7* ), were included for comparison. Subsequent photo‐elimination of another CO group from 4 or 7 converts the olefinic phosphane into a chelating four‐electron ligand, leading to (η6‐C6H3Me3)Cr(CO)[P(C7H7)2(η2‐C7H7)] ( 5 ) and (η5‐C5H5)Mn(CO)[P(C7H7)2(η2‐C7H7)] ( 8 ), respectively. The η2‐coordinated double bond in 5 and 8 can be displaced by trimethylphosphite to give (η6‐C6H3Me3)Cr(CO)[P(C7H7)3][P(OMe)3] ( 6 ) and (η5‐C5H5)Mn(CO)[P(C7H7)3][P(OMe)3] ( 9 ). The 31P and 13C NMR spectra of all complexes are discussed, and X‐ray structure analyses for 2 and 8 are presented. Prolonged irradiation of 7 and 8 led to a di(cycloheptatrienyl)phosphido‐bridged dimer, {(η5‐C5H5)Mn(CO)[P(C7H7)2]}2( 10 ). 相似文献
6.
Tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C7H7)3, and Tetra(1-cyclohepta-2,4,6-trienyl)phosphonium Tetrafluoroborate, [P(C7H7)4]BF4 The reaction of tris(trimethylsilyl)phosphane, P(SiMe3)3, with tropylium bromide, C7H7+Br?, in polar solvents such as dichloromethane or tetrahydrofuran gives P(C7H7)3 ( 1 ) and [P(C7H7)4]Br ( 2a ). According to the X-ray crystallographic structure determinations, all 1-cyclohepta-2,4,6-trienyl substituents are present in the boat conformation in both P(C7H7)3 ( 1 ) and the phosphonium salt, [P(C7H7)4]BF4 ( 2b ). The boat-shaped C7H7 rings are significantly more flattened if the phosphorus occupies the axial rather than the equatorial position at the ring substituent. Addition of a chalcogen to the lone pair at the central phosphorus atom of 1 leads to the chalcogena-phosphoranes EP(C7H7)3 (E = O ( 3a ), S ( 3b ), Se ( 3c )). The new 1-cyclohepta-2,4,6-trienyl-phosphorus compounds 1, 2 b and 3a–c were characterized by their 1H, 13C, and 31P NMR spectra in C6D6 solution. 相似文献
7.
Hongyan Wang Yaoming Xie R. Bruce King Henry F. Schaefer III 《Journal of organometallic chemistry》2008,693(20):3201-3212
Binuclear cycloheptatrienylchromium carbonyls of the type (C7H7)2Cr2(CO)n (n = 6, 5, 4, 3, 2, 1, 0) have been investigated by density functional theory. Energetically competitive structures with fully bonded heptahapto η7-C7H7 rings are not found for (C7H7)2Cr2(CO)n structures having two or more carbonyl groups. This result stands in contrast to the related (CnHn)2M2(CO)n (M = Mn, n = 6; M = Fe, n = 5; M = Co, n = 4) systems. Most of the predicted (C7H7)2Cr2(CO)n structures have bent trihapto or pentahapto C7H7 rings and CrCr distances in the range 2.4–2.5 Å suggesting formal triple bonds. In some cases rearrangement of the heptagonal C7H7 ring to a tridentate cyclopropyldivinyl or tridentate bis(carbene)alkyl ligand is observed. In addition structures with CO insertion into the C7H7–Cr bond are predicted for (C7H7)2Cr2(CO)n (n = 6, 4, 2). The global minima found for the (C7H7)2Cr2(CO)n derivatives for n = 6, 5, and 4 are (η5-C7H7)(OC)2CrCr(CO)4(η1-C7H7), (η3-C7H7)(OC)2CrCr(CO)3(η2,1- C7H7), and (η5-C7H7)2Cr2(CO)4, respectively. The global minima for (C7H7)2Cr2(CO)n (n = 3, 2) have rearranged C7H7 groups. Singlet and triplet structures with heptahapto η7-C7H7 rings are found for the dimetallocenes (η7-C7H7)2Cr2(CO) and (η7-C7H7)2Cr2, with the singlet structures being of much lower energies in both cases. 相似文献
8.
The preparation and properties of the compounds [Mo(η-C7H7)(dppe)Y] (Y = Cl, I, Me, H), [Mo(η-C7H7)(dppe)Cl]+A? (A = PF6, Br or I), {[Mo(η-C7H7)(dppe) Br]PF6}, {[Mo(η-C7H7)(dppe)I]PF6} and {[Mo(η-C7H7)(dppe)L]PF6} (L = CO, MeCN, or dppe) are described. 相似文献
9.
Lithium reductions of 7-chloronorbornadiene and of bis(7-norbornadienyl)mercury both provide (C7H7)2Li2 ( 5a ). This product is accompanied by C7H7Li2Cl ( 5c ) in the first case, and by C7H7Li ( 5b ) in the second. The theoretically anticipated properties of all three organolithiums are apparent in the consistent Cs symmetry of their hydrocarbon ligands, their protolytic destruction by 12-crown-4, and their significant J(C(7), Li) ( 5a , 7.6; 5b , 16.0; 5c 8.9 Hz). 相似文献
10.
Marita Hohmann Luise Krauth-Siegel K. Weidenhammer Wolfgang Schulze Manfred L. Ziegler 《无机化学与普通化学杂志》1981,481(10):95-106
Molecular and Crystal Structures of (CO)4W(μ-S-t-C4H9)2W(CO)4, η7-C7H7W(μ-SC6H4CH3)3W(CO)3 and η7-C7H7W(μ-S-n-C4H9)3W(CO)(μ-S-n-C4H9)2W(CO)4 The molecular structures of the two binuclear complexes (CO)4W(μ-S-t-C4H9)2W(CO)4 and η7-C7H7W(μ-SC6H4CH3)3W(CO)3 and of the tungsten cluster η7-C7H7W(μ-S-n-C4H9)3W(CO)-(μ-S-n-C4H9)2W(CO)4 respectively are described. In the nonlinear trinuclear cluster the central tungsten atom is connected to the two tungsten atoms by two and three μ-S-n-C4H9 bridges respectively and additionally by one W? W bond each. The coordination sphere of the W atoms is completed by a η7-C7H7 ring and four CO groups respectively; the central tungsten carries an additional CO group. 相似文献
11.
Duplex Stability of 7-Deazapurine DNA: Oligonucleotides containing 7-bromo- or 7-iodo-7-deazaguanine
The oligonucleotide building blocks, the phosphonates 1a, b and the phosphoramidites 2a, b derived from 7-iodo- and 7-bromo-7-deaza-2′-deoxyguanosines 3a, b were prepared. They were employed in solid-phase oligonucleotide synthesis of the alternating octamers d(Br7c7G-C)4 ( 8 ) and d(I7c7G-C)4 ( 9 ) as well as the homo-oligonucleotides d[(Br7c7G)5-G] ( 11 ) and d[(I7c7G)5-G] ( 12 ). The melting profiles and CD spectra of oligonucleotide duplexes were measured. The Tm values as well as the thermodynamic data were determined and correlated to the major-groove modification of this DNA. The self-complementary octamers 8 and 9 form more stable duplexes compared to the parent oligomer d(G-C)4. The heteroduplex of d[(I7c7G)5-G] ( 12 ) with d(C6) is slightly destabilized (ΔTm = ?12°) over that of d[(c7G)5-G] with d(C6). However, the complex of 12 with poly(C) is more stable than that of d[(c7G5-G)] with poly(C). 相似文献
12.
Reaction of [(η-C7H7)Mo(CO)3][PF6] with certain Group V donor ligands afforded monosubstituted complexes [(η-C7H7)Mo(CO)2L][PF6] (L = P(OPh)3, PPh3, PPh2Me, PPhMe2, AsPh3, SbPh3). These were reduced by NaBH4 to the corresponding cycloheptatriene complexes (1-6-η-C7H8)Mo(CO)2L. In addition, the preparation of alkylcycloheptatriene complexes (1-6-η-C7H7R)Mo(CO)2L (R = Me, L = P(OPh)3, PPh3, PPh2Me; R = t-Bu, L = PPh3) is described. Spectroscopic properties, including 13C NMR, are reported. 相似文献
13.
Novel silyl‐functionalized silsesquioxane building blocks have been prepared by treatment of Cy7Si7O9(OH)3 ( 1 , Cy = c‐C6H11) with hexachlorodisilane or hexachlorodisiloxane, respectively, in the presence of triethylamine. Reactions in a 1:1 molar ratio afforded the trichlorosilyl‐functionalized silsesquioxane derivatives Cy7Si8O12SiCl3 ( 2 ) and Cy7Si8O12OSiCl3 ( 3 ). Related bis(silsesquioxanes), (Cy7Si8O12)2 ( 4 ) and (Cy7Si8O12)2O ( 5 ) are accessible in a similar manner by employing a 2:1 molar ratio of the reactands. Compound 1 also served as a starting material in the preparation of the partially closed silsesquioxane cages Cy7Si7O11(OH)SiMe2 ( 6 ) and Cy7Si7O11(OH)Si(OEt)2 ( 7 ), while the related condensation product Cy7Si7O10(OSiMe3) ( 9 ) was made by AlCl3‐catalyzed elimination of water from Cy7Si7O9(OH)2OSiMe3 ( 8 ). The molecular structure of 9 was determined by X‐ray diffraction. 相似文献
14.
《Journal of organometallic chemistry》1993,460(1):C4-C5
Treatment of [(η-C7H7)Mo(μ-Cl)3Mo(η-C7H7)] (1) with ArNHLi (Ar = 2,6-diisopropylphenyl) gives the bridging-imido binuclear compound [(η-C7H7)Mo(μ-NAr)2Mo(η-C7H7)] (2), which is the first example of a transition-metal imido compound with a η-cycloheptatrienyl ligand. 相似文献
15.
An oligonucleotide analog containing 2′-O-methylpseudoisocytidine (P) and 2′-O-methyluridine (X) in an alternated homopyrimidine sequence (P-X-)7P-T can form triplexes with d-A-(G-A-)7G single strand and [d-A-(G-A-)7G]:[d-C-(T-C-)7T] duplex in neutral conditions. An UV mixing titration showed an end point of two units of (P-X-)7P-T to one unit of d-A-(G-A-)7G. This indicates that a [(P-X-)7P-T]·[d-A-(G-A-)7G]·[(P-X-)7P-T] is formed. The [(P-X-)7P-T]·[d-A-(G-A-)7G]·[(P-X-)7P-T] triplex is stable in a 0.1 M NaCl solution at neutral pH. However, the formation of triplex with [(P-X-)7P-T] and a duplex [d-A-(G-A-)7G]·[d-C-(T-C-)7T] can be accomplished in solution also containing 5 mM MgCl2. CD spectra of both triplexes showed large negative bands at wavelength 210–230 nm. Both triplexes can be detected by native gel electrophoresis. The thermal dissociation/association results indicate that this triplex dissociates to the single strands directly without going through a stable duplex intermediate. 相似文献
16.
S. S. Yarovoi Yu. V. Mironov S. F. Solodovnikov Z. A. Solodovnikova D. Yu. Naumov V. E. Fedorov 《Russian Journal of Coordination Chemistry》2006,32(10):712-722
The reactions of the octahedral anionic complexes [Re6Q7Br7]3? (Q = S, Se) with lanthanide bromides in DMF were studied. The reactions gave a series of compounds [Ln(DMF)8][Re6Q7Br7] (Q = S, Se) containing [Ln(DMF)8]3+ complex cations. The compounds were studied by single-crystal and powder X-ray diffraction and thermal analyses. The crystal structures of [Ln(DMF)8][Re6S7Br7] with Ln = La (I), Ce (II), Nd (III), Eu (IV), and Lu (V) and [Ln(DMF)8][Re6Se7Br7] with Ln = La (VI), Ce (VII), Pr (VIII), and Lu (IX) were determined. It was found that [Ln(DMF)8][Re6Q7Br7] (Q = S, Se) can be divided into three structural groups: I, II, and VI (type A), VII (type B), and III–V, VIII, IX (type C). The complex [Pr(DMF)8][Re6Se7Br7] was found to crystallize in two polymorphous modifications with type B and C structures. Presumably, the morphotropic transitions in the [Ln(DMF)8][Re6Q7Br7] series (Q = S, Se) are mainly related to the change in the configuration of the [Ln(DMF)8]3+ cations, resulting in a change in the packing motif of large complex ions in the crystals. The compounds [Ln(DMF)8][Re6Se7Br7] decompose according to a stepwise pattern, which suggests an intermediate formation of the complexes [Ln(DMF)6][Re6Se7Br7] (this was proved for Ln = Yb, Lu) with subsequent more extensive transformations, which affect also the cluster anion. 相似文献
17.
Four new ABZrF7 heptafluorozirconates (A = Rb, Tl; B = Ca, Cd) and their homologous heptafluorohafnates, all colorless, orthorhombic Cmcm (no63), Z = 4, have been synthesized by heating stoichiometric mixtures of RbF or TlF, CaF2 or CdF2 and ZrF4 (HfF4) in sealed platinum tubes at temperature ranging from 550 °C (Tl) to 600 °C (Rb). The crystal structures of both RbCdZrF7 and TlCdZrF7 have been solved from single‐crystal X‐rays diffraction data. Rietveld refinements were performed from X‐rays powder patterns for RbCaZrF7 and TlCaZrF7. In this series of heptafluorides, both B2+ and Zr4+ cations exhibit a pentagonal bipyramidal 7‐coordination. Their structural relationships with other heptafluorozirconates AIBIIZrF7 as well as β‐KYb2F7 are discussed. RbCaZrF7: a = 6.863(1) Å, b = 11.130(1) Å, c = 8.485(1) Å; TlCaZrF7: a = 6.868(1) Å, b = 11.165(1) Å, c = 8.486(1) Å; RbCdZrF7: a = 6.780(1) Å, b = 11.054(4) Å, c = 8.420(4) Å; TlCdZrF7: a = 6.784(3) Å, b = 11.099(2) Å, c = 8.424(9) Å. 相似文献
18.
Reaction of [(η-C7H7)Mo(CO)3][PF6] and [(η-C5H5)Fe(CO)2CH3CN][PF6] with ditertiary phosphine ligands afforded products of three types; the monosubstituted complexes [(Ring)M(CO)2Ph2P(CH2)nPPh2][PF6] (Ring = η-C7H7, M = Mo, N = 1; Ring = η-C5H5, M = Fe, N = 1 and 2), the chelated complexes [(Ring)M(CO)Ph2P(CH2)nPPh2][PF6] (Ring = η-C7H7, M = Mo, N = 1 and 2; Ring = η-C5H5, M = Fe, N = 1 and 2), and the dinuclear complex [{(η-C7H7)Mo(CO)2}2 -μ- Ph2PCH2CH2PPh2][(PF6)2]. Spectroscopic properties, including 31P NMR, are reported. 相似文献
19.
Elke Schwed Hans-Ulrich Hund H. William Bosch Heinz Berke 《Helvetica chimica acta》1991,74(1):189-196
Carbonyl(cycloheptatrienyl)iodo(phosphorus donor)tungstens ([WI(C7H7)(CO)L]; L = P(OMe)3, 1a ; L = P[O(i-Pr)]3, 1b ; L = PPh3, 1c ) were prepared from dicarbonyl(cycloheptatrienyl)iodotungsten ([WI(C7H7)(CO)2)] via a carbonyl-substitution process. Similarly, bromocarbonyl(phosphorus donor)(1,2,4,6-tetramethylcycloheptatrienyl)tungstens ([WBr(Me4C7H3)(CO)L]; L = P(OMe)3, 6a ; L = P[O(i-Pr)]3, 6b ; L = PPh3, 6c ) were obtained from the reaction of bromodicarbonyl(1,2,4,6)-tetramethylcycloheptatrienyl)tungsten ([WBr(Me4C7H3)(CO)2]; 4 ) with L. The reduction of 1a - c , 4 , and 6a , b with sodiumdihydridobis(2-methoxyethoxy)aluminium in toluene led to stable hydrido complexes [WH(R4C7H3)(CO)L] (R = H, L = P(OMe)3, 2a ; R = H, L = P[O(i-Pr)]3, 2b ; R = H, L = PPh3, 2c ; R = Me, L = P(OMe)3, 7a ; R = Me, L = P[O(i-Pr)]3, 7b ; R = Me, L = CO, 7d ). Complexes 2a and 7b were characterized by X-ray structure analyses. 相似文献
20.
Chemistry of Diruthenium and Dirhodium Analogues of Pentaborane(9): Synthesis and Characterization of Metal N,S‐Heterocyclic Carbene and B‐Agostic Complexes
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M. Sc. Dipak Kumar Roy M. Sc. Bijan Mondal M. Sc. R. S. Anju Prof. Sundargopal Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3640-3648
Building upon our earlier results on the synthesis of electron‐precise transition‐metal–boron complexes, we continue to investigate the reactivity of pentaborane(9) and tetraborane(10) analogues of ruthenium and rhodium towards thiazolyl and oxazolyl ligands. Thus, mild thermolysis of nido‐[(Cp*RuH)2B3H7] ( 1 ) with 2‐mercaptobenzothiazole (2‐mbtz) and 2‐mercaptobenzoxazole (2‐mboz) led to the isolation of Cp*‐based (Cp*=η5‐C5Me5) borate complexes 5 a , b [Cp*RuBH3L] ( 5 a : L=C7H4NS2; 5 b : L=C7H4NOS)) and agostic complexes 7 a , b [Cp*RuBH2(L)2], ( 7 a : L=C7H4NS2; 7 b : L=C7H4NOS). In a similar fashion, a rhodium analogue of pentaborane(9), nido‐[(Cp*Rh)2B3H7] ( 2 ) yielded rhodaboratrane [Cp*RhBH(L)2], 10 (L=C7H4NS2). Interestingly, when the reaction was performed with an excess of 2‐mbtz, it led to the formation of the first structurally characterized N,S‐heterocyclic rhodium‐carbene complex [(Cp*Rh)(L2)(1‐benzothiazol‐2‐ylidene)] ( 11 ) (L=C7H4NS2). Furthermore, to evaluate the scope of this new route, we extended this chemistry towards the diruthenium analogue of tetraborane(10), arachno‐[(Cp*RuCO)2B2H6] ( 3 ), in which the metal center possesses different ancillary ligands. 相似文献