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1.
Synthesis,Structure, and Reactivity of Diazene Adducts: Isolation of iso‐Diazene Stabilized as a Borane Adduct
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Dipl.‐Chem. Fabian Reiß Prof. Dr. Axel Schulz Dr. Alexander Villinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(37):11800-11811
This work describes the synthesis and full characterization of a series of GaCl3 and B(C6F5)3 adducts of diazenes R1?N?N?R2 (R1=R2=Me3Si, Ph; R1=Me3Si, R2=Ph). Trans‐Ph?N?N?Ph forms a stable adduct with GaCl3, whereas no adduct, but instead a frustrated Lewis acid–base pair is formed with B(C6F5)3. The cis‐Ph?N?N?Ph ? B(C6F5)3 adduct could only be isolated when UV light was used, which triggers the isomerization from trans‐ to cis‐Ph?N?N?Ph, which provides more space for the bulky borane. Treatment of trans‐Ph?N?N?SiMe3 with GaCl3 led to the expected trans‐Ph?N?N?SiMe3 ? GaCl3 adduct but the reaction with B(C6F5)3 triggered a 1,2‐Me3Si shift, which resulted in the formation of a highly labile iso‐diazene, Me3Si(Ph)N?N; stabilized as a B(C6F5)3 adduct. Trans‐Me3Si?N?N?SiMe3 forms a labile cis‐Me3Si?N?N?SiMe3 ? B(C6F5)3 adduct, which isomerizes to give the transient iso‐diazene species (Me3Si)2N?N ? B(C6F5)3 upon heating. Both iso‐diazene species insert easily into one B?C bond of B(C6F5)3 to afford hydrazinoboranes. All new compounds were fully characterized by means of X‐ray crystallography, vibrational spectroscopy, CHN analysis, and NMR spectroscopy. All compounds were further investigated by DFT and the bonding situation was assessed by natural bond orbital (NBO) analysis. 相似文献
2.
Ansa‐Complexes of [Mn(η5‐C5H5)(η6‐C6H6)]: Preparation,Characterization, and Reactivity of [n]Manganoarenophanes (n=1, 2, 3)
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Prof. Dr. Holger Braunschweig Dr. Alexander Damme Dr. Klaus Dück Dr. Marco Fuß Dr. Christian Hörl Dr. Thomas Kramer Dr. Ivo Krummenacher Dr. Thomas Kupfer Valerie Paprocki Christoph Schneider 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(42):14797-14803
We report the synthesis of [n]manganoarenophanes (n=1, 2) featuring boron, silicon, germanium, and tin as ansa‐bridging elements. Their preparation was achieved by salt‐elimination reactions of the dilithiated precursor [Mn(η5‐C5H4Li)(η6‐C6H5Li)]?pmdta (pmdta=N,N,N′,N′,N′′‐pentamethyldiethylenetriamine) with corresponding element dichlorides. Besides characterization by multinuclear NMR spectroscopy and elemental analysis, the identity of two single‐atom‐bridged derivatives, [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] and [Mn(η5‐C5H4)(η6‐C6H5)SiPh2], could also be determined by X‐ray structural analysis. We investigated for the first time the reactivity of these ansa‐cyclopentadienyl–benzene manganese compounds. The reaction of the distannyl‐bridged complex [Mn(η5‐C5H4)(η6‐C6H5)Sn2tBu4] with elemental sulfur was shown to proceed through the expected oxidative addition of the Sn?Sn bond to give a triatomic ansa‐bridge. The investigation of the ring‐opening polymerization (ROP) capability of [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] with [Pt(PEt3)3] showed that an unexpected, unselective insertion into the Cipso?Sn bonds of [Mn(η5‐C5H4)(η6‐C6H5)SntBu2] had occurred. 相似文献
3.
Cristiano Zuccaccia Gianfranco Bellachioma Giuseppe Cardaci Alceo Macchioni Barbara Binotti Carla Carfagna 《Helvetica chimica acta》2006,89(8):1524-1546
Palladacyclic compounds [Pd(C6H4(C6H5C?O)C?N? R)(N? N)] [X] (R = Et, iPr, 2,6‐iPr2C6H3; N? N = bpy = 2,2′‐bipyridine, or 1,4‐(o,o′‐dialkylaryl)‐1,4‐diazabuta‐1,3‐dienes; [X]? = [BF4]? or [PF6]?) were synthesized from the dimers [{Pd(C6H4(C6H5C?O)C?N? R)(μ‐Cl)}2] and N? N ligands. Their interionic structure in CD2Cl2 was determined by means of 19F,1H‐HOESY experiments and compared with that in the solid state derived from X‐ray single‐crystal studies. [Pd(C6H4(C6H5C?O)C?N? R)(N? N)] [X] complexes were found to copolymerize CO and p‐methylstyrene affording syndiotactic or isotactic copolymers when bpy or 1,4‐(o,o′‐dimethylaryl)‐1,4‐diazabuta‐1,3‐dienes were used, respectively. The reactions with CO and p‐methylstyrene of the bpy derivatives were investigated. Two intermediates derived from a single and a double insertion of CO into the Pd? C bonds were isolated and completely characterized in solution. 相似文献
4.
Experimental and Computational Studies on the Reactivity of a Terminal Thorium Imidometallocene towards Organic Azides and Diazoalkanes
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Dr. Wenshan Ren Enwei Zhou Bo Fang Dr. Guohua Hou Prof. Guofu Zi Prof. De‐Cai Fang Dr. Marc D. Walter 《Angewandte Chemie (International ed. in English)》2014,53(42):11310-11314
The reaction of the base‐free terminal thorium imido complex [{η5‐1,2,4‐(Me3C)3C5H2}2Th?N(p‐tolyl)] ( 1 ) with p‐azidotoluene yielded irreversibly the tetraazametallacyclopentene [{η5‐1,2,4‐(Me3C)3C5H2}2Th{N(p‐tolyl)N?N? N(p‐tolyl)}] ( 2 ), whereas the bridging imido complex [{[η5‐1,2,4‐(Me3C)3C5H2]Th(N3)2}2{μ‐N(p‐tolyl)}2][(n‐C4H9)4N]2 ( 3 ) was isolated from the reaction of 1 with [(n‐C4H9)4N]N3. Unexpectedly, upon the treatment of 1 with 9‐diazofluorene, the NN bond was cleaved, an N atom was transferred, and the η2‐diazenido iminato complex [{η5‐1,2,4‐(Me3C)3C5H2}2Th{η2‐[N?N(p‐tolyl)]}{N?(9‐C13H8)}] ( 4 ) was formed. In contrast, the reaction of 1 with Me3SiCHN2 gave the nitrilimido complex [{η5‐1,2,4‐(Me3C)3C5H2}2Th{NH(p‐tolyl)}{N2CSiMe3}] ( 5 ), which slowly converted into [{η5‐1,2,4‐(Me3C)3C5H2}{η5:κ‐N‐1,2‐(Me3C)2‐4‐CMe2(CH2NN?CHSiMe3)C5H2}Th{NH(p‐tolyl)}] ( 6 ) by intramolecular C? H bond activation. The experimental results are complemented by density functional theory (DFT) studies. 相似文献
5.
Mehrdad Pourayoubi Fatemeh Karimi Ahmadabad Hossein Eshtiagh‐Hosseini Monika Ku
erkov Vclav Eigner Michal Duek 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(10):1181-1185
The mixed‐amide phosphinates, rac‐phenyl (N‐methylcyclohexylamido)(p‐tolylamido)phosphinate, C20H27N2O2P, (I), and rac‐phenyl (allylamido)(p‐tolylamido)phosphinate, C16H19N2O2P, (II), were synthesized from the racemic phosphorus–chlorine compound (R,S)‐(Cl)P(O)(OC6H5)(NHC6H4‐p‐CH3). Furthermore, the phosphorus–chlorine compound ClP(O)(OC6H5)(NH‐cyclo‐C6H11) was synthesized for the first time and used for the synthesis of rac‐phenyl (benzylamido)(cyclohexylamido)phosphinate, C19H25N2O2P, (III). The strategies for the synthesis of racemic mixed‐amide phosphinates are discussed. The P atom in each compound is in a distorted tetrahedral (N1)P(=O)(O)(N2) environment. In (I) and (II), the p‐tolylamido substituent makes a longer P—N bond than those involving the N‐methylcyclohexylamido and allylamido substituents. In (III), the differences between the P—N bond lengths involving the cyclohexylamido and benzylamido substituents are not significant. In all three structures, the phosphoryl O atom takes part with the N—H unit in hydrogen‐bonding interactions, viz. an N—H...O=P hydrogen bond for (I) and (N—H)(N—H)...O=P hydrogen bonds for (II) and (III), building linear arrangements along [001] for (I) and along [010] for (III), and a ladder arrangement along [100] for (II). 相似文献
6.
Miroslav Novák Marek Bouška Dr. Libor Dostál Dr. Aleš Růžička Dr. Alexander Hoffmann Prof. Dr. Sonja Herres‐Pawlis Dr. Roman Jambor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7820-7829
We report here the synthesis of new C,N‐chelated chlorostannylenes and germylenes L3MCl (M=Sn( 1 ), Ge ( 2 )) and L4MCl (M=Sn( 3 ), Ge ( 4 )) containing sterically demanding C,N‐chelating ligands L3, 4 (L3=[2,4‐di‐tBu‐6‐(Et2NCH2)C6H2]?; L4=[2,4‐di‐tBu‐6‐{(C6H3‐2′,6′‐iPr2)N=CH}C6H2]?). Reductions of 1 – 4 yielded three‐coordinate C,N‐chelated distannynes and digermynes [L3, 4M ]2 for the first time ( 5 : L3, M=Sn, 6 : L3, M=Ge, 7 : L4, M=Sn, 8 : L4, M=Ge). For comparison, the four‐coordinate distannyne [L5Sn]2 ( 10 ) stabilized by N,C,N‐chelate L5 (L5=[2,6‐{(C6H3‐2′,6′‐Me2)N?CH}2C6H3]?) was prepared by the reduction of chlorostannylene L5SnCl ( 9 ). Hence, we highlight the role of donor‐driven stabilization of tetrynes. Compounds 1 – 10 were characterized by means of elemental analysis, NMR spectroscopy, and in the case of 1 , 2 , 5 – 7 , and 10 , also by single‐crystal X‐ray diffraction analysis. The bonding situation in either three‐ or four‐coordinate distannynes 5 , 7 , and 10 was evaluated by DFT calculations. DFT calculations were also used to compare the nature of the metal–metal bond in three‐coordinate C,N‐chelating distannyne [L3Sn]2 ( 5 ) and related digermyme [L3Ge]2 ( 6 ). 相似文献
7.
Lisa Saunders Baugh Joseph A. Sissano 《Journal of polymer science. Part A, Polymer chemistry》2002,40(10):1633-1651
Dimethylaluminum complexes bearing bidentate amidate, oxypyridine, and salicylaldimine N,O‐ligands and tridentate N,N′,N″‐pyridyliminoamide ligands were synthesized and spectroscopically characterized. The complexes were investigated in both neutral and borane‐activated cationic forms, along with bidentate N,N′‐ligated aluminum amidinates, as catalysts for the polymerization of methyl methacrylate, ?‐caprolactone, and propylene oxide. The neutral complexes generally did not carry out polymerization, but the polymerization/oligomerization of all three monomers was achieved when the various catalysts were activated with B(C6F5)3 or [Ph3C]+[B(C6F5)4]?. The N,O‐ligated cations were much less active for polymerization than the analogous, more stable N,N′‐ligated amidinate cations; both types of cationic complexes catalyzed the ring‐opening cationic polymerization of tetrahydrofuran. B(C6F5)3 and [Ph3C]+[B(C6F5)4]? also independently carried out the oligomerization of propylene oxide. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1633–1651, 2002 相似文献
8.
Chemo‐Enzymatic Synthesis of Position‐Specifically Modified RNA for Biophysical Studies including Light Control and NMR Spectroscopy
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Sara Keyhani Thomas Goldau Anja Blümler Prof. Dr. Alexander Heckel Prof. Dr. Harald Schwalbe 《Angewandte Chemie (International ed. in English)》2018,57(37):12017-12021
The investigation of non‐coding RNAs requires RNAs containing modifications at every possible position within the oligonucleotide. Here, we present the chemo‐enzymatic RNA synthesis containing photoactivatable or 13C,15N‐labelled nucleosides. All four ribonucleotides containing ortho‐nitrophenylethyl (NPE) photocages, photoswitchable azobenzene C‐nucleotides and 13C,15N‐labelled nucleotides were incorporated position‐specifically in high yields. We applied this approach for the synthesis of light‐inducible 2′dG‐sensing riboswitch variants and detected ligand‐induced structural reorganization upon irradiation by NMR spectroscopy. This chemo‐enzymatic method opens the possibility to incorporate a wide range of modifications at any desired position of RNAs of any lengths beyond the limits of solid‐phase synthesis. 相似文献
9.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(6):696-702
A concise and efficient synthesis of 6‐benzimidazolyl‐5‐nitrosopyrimidines has been developed using Schiff base‐type intermediates derived from N4‐(2‐aminophenyl)‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine. 6‐Methoxy‐N4‐{2‐[(4‐methylbenzylidene)amino]phenyl}‐5‐nitrosopyrimidine‐2,4‐diamine, (I), and N4‐{2‐[(ethoxymethylidene)amino]phenyl}‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine, (III), both crystallize from dimethyl sulfoxide solution as the 1:1 solvates C19H18N6O2·C2H6OS, (Ia), and C14H16N6O3·C2H6OS, (IIIa), respectively. The interatomic distances in these intermediates indicate significant electronic polarization within the substituted pyrimidine system. In each of (Ia) and (IIIa), intermolecular N—H…O hydrogen bonds generate centrosymmetric four‐molecule aggregates. Oxidative ring closure of intermediate (I), effected using ammonium hexanitratocerate(IV), produced 4‐methoxy‐6‐[2‐(4‐methylphenyl‐1H‐benzimidazol‐1‐yl]‐5‐nitrosopyrimidin‐2‐amine, C19H16N6O2, (II) [Cobo et al. (2018). Private communication (CCDC 1830889). CCDC, Cambridge, England], where the extent of electronic polarization is much less than in (Ia) and (IIIa). A combination of N—H…N and C—H…O hydrogen bonds links the molecules of (II) into complex sheets. 相似文献
10.
Beatrice Calmuschi‐Cula Irmgard Kalf Claudia Timofte Ulli Englert 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(2):m48-m51
The crystal structures of (SP‐4‐4)‐[rac‐2‐(1‐aminoethyl)phenyl‐κ2C1,N]chlorido(pyridine‐κN)palladium(II), [Pd(C8H10N)Cl(C5H5N)], (I), (SP‐4‐4)‐[rac‐2‐(1‐aminoethyl)phenyl‐κ2C1,N]bromido(pyridine‐κN)palladium(II), [PdBr(C8H10N)(C5H5N)], (II), (SP‐4‐4)‐[rac‐2‐(1‐aminoethyl)‐5‐bromophenyl‐κ2C1,N]bromido(4‐methylpyridine‐κN)palladium(II), [PdBr(C8H9BrN)(C6H7N)], (III), and (SP‐4‐4)‐[rac‐2‐(1‐aminoethyl)‐5‐bromophenyl‐κ2C1,N]iodido(4‐methylpyridine‐κN)palladium(II), [Pd(C8H9BrN)I(C6H7N)], (IV), are reported. The latter is the first iodide complex in this class of compounds. All four complexes crystallize in the same space group, viz.I41/a, with very similar lattice parameters a and more flexible lattice parameters c. Their packing corresponds to that of their enantiomerically pure congeners, which crystallize in the t2 subgroup I41. 相似文献
11.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(9):674-681
Three photoluminescent complexes containing either ZnII or CdII have been synthesized and their structures determined. Bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ2N 1,N 5]bis(dicyanamido‐κN 1)zinc(II), [Zn(C12H10N6)2(C2N3)2], (I), bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ2N 1,N 5]bis(dicyanamido‐κN 1)cadmium(II), [Cd(C12H10N6)2(C2N3)2], (II), and bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ2N 1,N 5]bis(tricyanomethanido‐κN 1)cadmium(II), [Cd(C12H10N6)2(C4N3)2], (III), all crystallize in the space group P , with the metal centres lying on centres of inversion, but neither analogues (I) and (II) nor CdII complexes (II) and (III) are isomorphous. A combination of N—H…N and C—H…N hydrogen bonds and π–π stacking interactions generates three‐dimensional framework structures in (I) and (II), and a sheet structure in (III). The photoluminescence spectra of (I)–(III) indicate that the energies of the π–π* transitions in the coordinated triazole ligand are modified by minor changes of the ligand geometry associated with coordination to the metal centres. 相似文献
12.
Vladimir V. Chernyshov Yuri V. Gatilov Olga I. Yarovaya Igor P. Koskin Spartak S. Yarovoy Konstantin A. Brylev Nariman F. Salakhutdinov 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(12):1675-1680
The possibility of a single‐stage solvent‐free stereoselective synthesis of a spirocyclic compound from the natural bicyclic monoterpenoid (?)‐fenchone and anthranilamide has been shown for the first time. The molecular and crystal structure of (1R,2S,4S)‐1,3,3‐trimethyl‐1′H‐spiro[bicyclo[2.2.1]heptane‐2,2′‐quinazolin]‐4′(3′H)‐one, C17H22N2O, was established by X‐ray diffraction though the chirality was assumed via the known reactant connectivity and 1H and 13C NMR spectroscopy. It has shown that in the molecule, for steric reasons, there is an elongation of the Me2C—C(N)N bond to 1.603 (5) Å. The formation of dimers via N—H…O=C hydrogen bonds with an interaction energy of 93.30 kJ mol?1 and through cavities (33.7% of the unit‐cell volume) was established in the packing of the molecules. There are no π‐stacking interactions in the structure. 相似文献
13.
Avelino Martín Miguel Mena Adrin Prez‐Redondo Carlos Ylamos 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(5):m157-m159
The reaction of the imide–nitride complex [{Ti(η5‐C5Me5)(μ‐NH)}3(μ3‐N)] with potassium iodide in pyridine at room temperature affords the adduct di‐μ‐iodido‐1:1′κ4I‐bis{tri‐μ3‐imido‐1:2:3κ3N;1:2:4κ3N;1:3:4κ3N‐μ3‐nitrido‐2:3:4κ3N‐tris[2,3,4(η5)‐pentamethylcyclopentadienyl](pyridine‐1κN)‐tetrahedro‐potassiumtrititanium(IV)}, [K2Ti6(C10H15)6I2N2(NH)6(C5H5N)2] or [(C5H5N)(μ‐I)K{(μ3‐NH)3Ti3(η5‐C5Me5)3(μ3‐N)}]2. The crystal structure contains two [KTi3N4] cube‐type units held together by two bridging I atoms. There is a centre of inversion located in the middle of this unprecedented discrete K2I2 unit. The geometry around K is best described as distorted trigonal prismatic, with three imide groups, two bridging I atoms and one pyridine ligand. 相似文献
14.
Daniel E. Vicentes Ricaurte Rodríguez Patricia Ochoa Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(10):1405-1416
A concise and efficient synthesis of a series of amino‐substituted benzimidazole–pyrimidine hybrids has been developed, starting from the readily available N4‐(2‐aminophenyl)‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine. In each of N5‐benzyl‐6‐methoxy‐4‐(2‐phenyl‐1H‐benzo[d]imidazol‐1‐yl)pyrimidine‐2,5‐diamine, C25H22N6O, (I), 6‐methoxy‐N5‐(4‐methoxybenzyl)‐4‐[2‐(4‐methoxyphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, C27H26N6O3, (III), 6‐methoxy‐N5‐(4‐nitrobenzyl)‐4‐[2‐(4‐nitrophenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, C25H20N8O5, (IV), the molecules are linked into three‐dimensional framework structures, using different combinations of N—H…N, N—H…O, C—H…O, C—H…N and C—H…π hydrogen bonds in each case. Oxidative cleavage of 6‐methoxy‐N5‐(4‐methylbenzyl)‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, (II), with diiodine gave 6‐methoxy‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, which crystallized as a monohydrate, C19H18N6O·H2O, (V), and reaction of (V) with trifluoroacetic acid gave two isomeric products, namely N‐{5‐amino‐6‐methoxy‐6‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidin‐2‐yl}‐2,2,2‐trifluoroacetamide, which crystallized as an ethyl acetate monosolvate, C21H17F3N6O2·C4H8O2, (VI), and N‐{2‐amino‐6‐methoxy‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidin‐5‐yl}‐2,2,2‐trifluoroacetamide, which crystallized as a methanol monosolvate, C21H17F3N6O2·CH4O, (VIIa). For each of (V), (VI) and (VIIa), the supramolecular assembly is two‐dimensional, based on different combinations of O—H…N, N—H…O, N—H…N, C—H…O and C—H…π hydrogen bonds in each case. Comparisons are made with some related structures. 相似文献
15.
K. Ravikumar B. Sridhar Harihara Krishnan A. N. Singh 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(1):o15-o17
The crystal structures of almotriptan {systematic name: N,N‐dimethyl‐2‐[5‐(pyrrolidin‐1‐ylsulfonylmethyl)‐1H‐indol‐3‐yl]ethanamine}, C17H25N3O2S, and almotriptan malate {systematic name: N,N‐dimethyl‐2‐[5‐(pyrrolidin‐1‐ylsulfonylmethyl)‐1H‐indol‐3‐yl]ethanaminium malate, C17H26N3O2S+·C4H5O5−, a novel selective serotonin 1B/D agonist, have been determined in order to gain further insight into the structure–activity relationships of triptans. The two structures differ in the orientation of their sulfonylpyrrolidine side chains. A comparison with other triptans reveals that molecules of almotriptan, sumatriptan, zolmitriptan and rizatriptan can adopt two principal conformations. N—H...N, N—H...O and O—H...O hydrogen bonds are responsible for the molecular packing. 相似文献
16.
Clifton L. Wagner Dr. Lizhi Tao Emily J. Thompson Dr. Troy A. Stich Dr. Jingdong Guo Dr. James C. Fettinger Prof. Louise A. Berben Prof. R. David Britt Prof. Shigeru Nagase Prof. Philip P. Power 《Angewandte Chemie (International ed. in English)》2016,55(35):10444-10447
The synthesis of the first linear coordinated CuII complex Cu{N(SiMe3)Dipp}2 ( 1 Dipp=C6H5‐2,6Pri2) and its CuI counterpart [Cu{N(SiMe3)Dipp}2]? ( 2 ) is described. The formation of 1 proceeds through a dispersion force‐driven disproportionation, and is the reaction product of a CuI halide and LiN(SiMe3)Dipp in a non‐donor solvent. The synthesis of 2 is accomplished by preventing the disproportionation into 1 by using the complexing agent 15‐crown‐5. EPR spectroscopy of 1 provides the first detailed study of a two‐coordinate transition‐metal complex indicating strong covalency in the Cu?N bonds. 相似文献
17.
M. Sc. Ireen Schrader Dr. Kornelia Zeckert Dr. Stefan Zahn 《Angewandte Chemie (International ed. in English)》2014,53(50):13698-13700
Hypercoordination of main‐group elements such as the heavier Group 14 elements (silicon, germanium, tin, and lead) usually requires strong electron‐withdrawing ligands and/or donating groups. Herein, we present the synthesis and characterization of two hexaaryltin(IV) dianions in form of their dilithium salts [Li2(thf)2{Sn(2‐pyMe)6}] (pyMe=C5H3N‐5‐Me) ( 2 ) and [Li2{Sn(2‐pyOtBu)6}] (pyOtBu=C5H3N‐6‐OtBu) ( 3 ). Both complexes are stable in the solid state and solution under inert conditions. Theoretical investigations of compound 2 reveal a significant valence 5s‐orbital contribution of the tin atom forming six strongly polarized tin–carbon bonds. 相似文献
18.
Thomas Gelbrich Denise Rossi Ulrich J. Griesser 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(2):o65-o70
Polymorph (Ia) of eldoral [5‐ethyl‐5‐(piperidin‐1‐yl)barbituric acid or 5‐ethyl‐5‐(piperidin‐1‐yl)‐1,3‐diazinane‐2,4,6‐trione], C11H17N3O3, displays a hydrogen‐bonded layer structure parallel to (100). The piperidine N atom and the barbiturate carbonyl group in the 2‐position are utilized in N—H...N and N—H...O=C hydrogen bonds, respectively. The structure of polymorph (Ib) contains pseudosymmetry elements. The two independent molecules of (Ib) are connected via N—H...O=C(4/6‐position) and N—H...N(piperidine) hydrogen bonds to give a chain structure in the [100] direction. The hydrogen‐bonded layers, parallel to (010), formed in the salt diethylammonium 5‐ethyl‐5‐(piperidin‐1‐yl)barbiturate [or diethylammonium 5‐ethyl‐2,4,6‐trioxo‐5‐(piperidin‐1‐yl)‐1,3‐diazinan‐1‐ide], C4H12N+·C11H16N3O3−, (II), closely resemble the corresponding hydrogen‐bonded structure in polymorph (Ia). Like many other 5,5‐disubstituted derivatives of barbituric acid, polymorphs (Ia) and (Ib) contain the R22(8) N—H...O=C hydrogen‐bond motif. However, the overall hydrogen‐bonded chain and layer structures of (Ia) and (Ib) are unique because of the involvement of the hydrogen‐bond acceptor function in the piperidine group. 相似文献
19.
Tetrylenes chelated by bifunctional β‐diketiminate ligand: structure and possible applications
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The synthesis and structure of heteroleptic tetrylenes containing bifunctional β‐diketiminate ligand are reported. Compounds were prepared via a protolytic reaction of free β‐diketimine {N‐[(2‐MeO)C6H5]}N═C(Me)CH═C(Me)N(H){N′‐[(2‐MeO)C6H5]} (LCOH) and {N‐[(2‐MeO)C6H5]}N?CHCH?CHN(H){N′‐[(2‐MeO)C6H5]} (LHOH), respectively, with corresponding bis(amide) – M[N(SiMe3)2]2 (M = Ge, Sn, Pb) – in equimolar ratio or via the salt elimination route from lithium precursors generated from LHOH/LCOH species and slight excess of SnCl2 or GeCl2.dioxane complex. Only heteroleptic complexes were obtained by the mentioned methods. Products were characterized by multinuclear NMR spectroscopy techniques and structures of four of them have been determined by X‐ray diffraction methods. Complexes LHOGeCl and LCOSnN(SiMe3)2 crystallize as monomers with the three‐coordinated metal centres by one chloro or amido ligand and one bidentate β‐diketiminato unit, in contrast to the structure of LCOSnCl, which reveals a dimeric character and compound LCOPbN(SiMe3)2, where the central atom of lead is five‐coordinated by methoxy groups of the ligand. Complex LCOSnN(SiMe3)2 was tested as a catalyst for polymerization of various epoxides. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
20.
Friedrich Schoder Ulrike Plaia Robert Metzner Wilfried Sperber Wolfgang Beck Wolf Peter Fehlhammer Prof. Dr. 《无机化学与普通化学杂志》2010,636(5):700-709
The reactions of [Re(CO)6]+, [FeCp(CO)2CS]+ and [FeCp(CNPh)3]+ with the metallo nitrile ylides [M–{C+=N–C–(H)CO2Et}(CO)5]– (M = Cr, W) and the chromio nitrile imine [Cr–{C+=N–N–H}(CO)5]– (generated by mono‐α‐deprotonation of the parent isocyanide complexes) to give neutral 5‐metallated 1,3‐oxazolin‐ ( 1 ), 1,3‐thiazolin‐ ( 2 ), imidazolin‐ ( 3 , 4 ), 1,3,4‐oxdiazolin‐ ( 5 ), 1,3,4‐thiadiazolin‐ ( 6 ) and 1,3,4‐triazolin‐2‐ylidene ( 8 ) chromium and tungsten complexes represent the first all‐organometallic versions of Huisgen’s 1,3‐dipolar cycloadditions. The formation of 6 and 8 is accompanied by partial decomposition to (OC)5Cr–C≡N–FeCpL2 {L = CO ( 7 ), CNPh ( 9 )}. The structures of 4a and 5 have been characterized by X‐ray diffraction. 相似文献