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1.
Reactivity of TpMe2‐Supported Yttrium Alkyl Complexes toward Aromatic N‐Heterocycles: Ring‐Opening or CC Bond Formation Directed by CH Activation 下载免费PDF全文
Dr. Weiyin Yi Prof. Dr. Jie Zhang Shujian Huang Prof. Dr. Linhong Weng Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):867-876
Unusual chemical transformations such as three‐component combination and ring‐opening of N‐heterocycles or formation of a carbon–carbon double bond through multiple C–H activation were observed in the reactions of TpMe2‐supported yttrium alkyl complexes with aromatic N‐heterocycles. The scorpionate‐anchored yttrium dialkyl complex [TpMe2Y(CH2Ph)2(THF)] reacted with 1‐methylimidazole in 1:2 molar ratio to give a rare hexanuclear 24‐membered rare‐earth metallomacrocyclic compound [TpMe2Y(μ‐N,C‐Im)(η2‐N,C‐Im)]6 ( 1 ; Im=1‐methylimidazolyl) through two kinds of C–H activations at the C2‐ and C5‐positions of the imidazole ring. However, [TpMe2Y(CH2Ph)2(THF)] reacted with two equivalents of 1‐methylbenzimidazole to afford a C–C coupling/ring‐opening/C–C coupling product [TpMe2Y{η3‐(N,N,N)‐N(CH3)C6H4NHCH?C(Ph)CN(CH3)C6H4NH}] ( 2 ). Further investigations indicated that [TpMe2Y(CH2Ph)2(THF)] reacted with benzothiazole in 1:1 or 1:2 molar ratio to produce a C–C coupling/ring‐opening product {(TpMe2)Y[μ‐η2:η1‐SC6H4N(CH?CHPh)](THF)}2 ( 3 ). Moreover, the mixed TpMe2/Cp yttrium monoalkyl complex [(TpMe2)CpYCH2Ph(THF)] reacted with two equivalents of 1‐methylimidazole in THF at room temperature to afford a trinuclear yttrium complex [TpMe2CpY(μ‐N,C‐Im)]3 ( 5 ), whereas when the above reaction was carried out at 55 °C for two days, two structurally characterized metal complexes [TpMe2Y(Im‐TpMe2)] ( 7 ; Im‐TpMe2=1‐methyl‐imidazolyl‐TpMe2) and [Cp3Y(HIm)] ( 8 ; HIm=1‐methylimidazole) were obtained in 26 and 17 % isolated yields, respectively, accompanied by some unidentified materials. The formation of 7 reveals an uncommon example of construction of a C?C bond through multiple C–H activations. 相似文献
2.
Guo‐Wu Lin Yue Wang Tao Lu 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(4):m179-m181
The title compound, [Co(C19H15N3O5S)(C12H8N2)]·5H2O, has a moderately distorted octahedral coordination environment composed of two N atoms of a 1,10‐phenanthroline ligand and one N and three O atoms of an N‐{[4‐(1,3‐benzothiazol‐2‐yl)anilino]carbonylmethyl}iminodiacetate (ZL‐52−) ligand. The ring systems of the phenanthroline and ZL‐52− ligands are coplanar and the complexes pack in layers parallel to the ab plane with the rings of adjacent complexes facing one another. The layers stack along the c axis and are linked by hydrogen bonds involving the five water solvent molecules in the asymmetric unit and O atoms of the acetate groups of the ZL‐52− ligand. This is believed to be the first crystal structure of a complex of a 2‐(4‐aminophenyl)benzothiazole ligand. 相似文献
3.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(11):923-929
Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site‐specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group‐7‐based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence. The inherent luminecscent nature of some photoCORMs and the change in emission wavelength upon CO release also provide a covenient means to track the entry of the prodrug and, in some cases, both the entry and CO release from the prodrug. In continuation of the research circumscribing the development of trackable photoCORMs and also to graft such molecules covalently to conventional delivery vehicles, we report herein the synthesis and structures of three rhenium carbonyl complexes, namely, fac‐tricarbonyl[2‐(pyridin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′](4‐vinylpyridine‐κN )rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2S)(CO)3](CF3SO3), ( 1 ), fac‐tricarbonyl[2‐(quinolin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′](4‐vinylpyridine‐κN )rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C16H10N2S)(CO)3](CF3SO3), ( 2 ), and fac‐tricarbonyl[1,10‐phenanthroline‐κ2N ,N ′](4‐vinylpyridine‐κN )rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2)(CO)3](CF3SO3), ( 3 ). In all three complexes, the ReI center resides in a distorted octahedral coordination environment. These complexes exhibit CO release upon exposure to low‐power UV light. The apparent CO release rates of the complexes have been measured to assess their comparative CO‐donating capacity. The three complexes are highly luminescent and this in turn provides a convenient way to track the entry of the prodrug molecules within biological targets. 相似文献
4.
Alkali Metal and Alkaline Earth Metal Complexes with the Bis(borane‐diphenylphosphanyl)amido Ligand – Synthesis,Structures, and Catalysis for Ring‐Opening Polymerization of ϵ‐Caprolactone
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Jayeeta Bhattacharjee Suman Das T. Dhileep N. Reddy Hari Pada Nayek Bhabani S. Mallik Tarun K. Panda 《无机化学与普通化学杂志》2016,642(2):118-127
The syntheses of lithium and alkaline earth metal complexes with the bis(borane‐diphenylphosphanyl)amido ligand ( 1 ‐ H ) of molecular formulas [{κ2‐N(PPh2(BH3))2}Li(THF)2] ( 2 ) and [{κ3‐N(PPh2(BH3))2}2M(THF)2] [(M = Ca ( 3 ), Sr ( 4 ), Ba ( 5 )] are reported. The lithium complex 2 was obtained by treatment of bis(borane‐diphenylphosphanyl)amine ( 1 ‐ H ) with lithium bis(trimethylsilyl)amide in a 1:1 molar ratio via the silylamine elimination method. The corresponding homoleptic alkaline earth metal complexes 3 – 5 were prepared by two synthetic routes – first, the treatment of metal bis(trimethylsilyl)amide and protio ligand 1 ‐ H via the elimination of silylamine, and second, through salt metathesis reaction involving respective metal diiodides and lithium salt 2 . The molecular structures of lithium complex 2 and barium complex 5 were established by single‐crystal X‐ray diffraction analysis. In the solid‐state structure of 2 , the lithium ion is ligated by amido nitrogen atoms and hydrogen atoms of the BH3 group in κ2‐coordination of the ligand 1 resulting in a distorted tetrahedral geometry around the lithium ion. However, in complex 5 , κ3‐coordination of the ligand 1 was observed, and the barium ion adopted a distorted octahedral arrangement. The metal complex 5 was tested as catalyst for the ring opening polymerization of ?‐caprolactone. High activity for the barium complex 5 towards ring opening polymerization (ROP) of ?‐caprolactone with a narrow polydispersity index was observed. Additionally, first‐principle calculations to investigate the structure and coordination properties of alkaline earth metal complexes 3 – 5 as a comparative study between the experimental and theoretical findings were described. 相似文献
5.
Michael Nussbaum Dr. Oliver Schuster Prof. Dr. Martin Albrecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17517-17527
A ditopic benzobis(carbene) ligand precursor was prepared that contained a chelating pyridyl moiety to ensure co‐planarity of the carbene ligand and the coordination plane of a bound octahedral metal center. Bimetallic ruthenium complexes comprising this ditopic ligand [L4Ru‐C,N‐bbi‐C,N‐RuL4] were obtained by a transmetalation methodology (C,N‐bbi‐C,N=benzobis(N‐pyridyl‐N′‐methyl‐imidazolylidene). The two metal centers are electronically decoupled when the ruthenium is in a pseudotetrahedral geometry imparted by a cymene spectator ligand (L4=[(cym)Cl]). Ligand exchange of the Cl?/cymene ligands for two bipyridine or four MeCN ligands induced a change of the coordination geometry to octahedral. As a consequence, the ruthenium centers, separated through space by more than 10 Å, become electronically coupled, which is evidenced by two distinctly different metal‐centered oxidation processes that are separated by 134 mV (L4=[(bpy)2]; bpy=2,2′‐bipyridine) and 244 mV (L4=[(MeCN)4]), respectively. Hush analysis of the intervalence charge‐transfer bands in the mixed‐valent species indicates substantial valence delocalization in both complexes (delocalization parameter Γ=0.41 and 0.37 in the bpy and MeCN complexes, respectively). Spectroelectrochemical measurements further indicated that the mixed‐valent RuII/RuIII species and the fully oxidized RuIII/RuIII complexes gradually decompose when bound to MeCN ligands, whereas the bpy spectators significantly enhance the stability. These results demonstrate the efficiency of carbenes and, in particular, of the bbi ligand scaffold for mediating electron transfer and for the fabrication of molecular redox switches. Moreover, the relevance of spectator ligands is emphasized for tailoring the degree of electronic communication through the benzobis(carbene) linker. 相似文献
6.
Zhongbao Jian Prof. Dr. Dongmei Cui Prof. Dr. Zhaomin Hou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(9):2674-2684
A series of rare‐earth‐metal–hydrocarbyl complexes bearing N‐type functionalized cyclopentadienyl (Cp) and fluorenyl (Flu) ligands were facilely synthesized. Treatment of [Y(CH2SiMe3)3(thf)2] with equimolar amount of the electron‐donating aminophenyl‐Cp ligand C5Me4H‐C6H4‐o‐NMe2 afforded the corresponding binuclear monoalkyl complex [({C5Me4‐C6H4‐o‐NMe(μ‐CH2)}Y{CH2SiMe3})2] ( 1 a ) via alkyl abstraction and C? H activation of the NMe2 group. The lutetium bis(allyl) complex [(C5Me4‐C6H4‐o‐NMe2)Lu(η3‐C3H5)2] ( 2 b ), which contained an electron‐donating aminophenyl‐Cp ligand, was isolated from the sequential metathesis reactions of LuCl3 with (C5Me4‐C6H4‐o‐NMe2)Li (1 equiv) and C3H5MgCl (2 equiv). Following a similar procedure, the yttrium‐ and scandium–bis(allyl) complexes, [(C5Me4‐C5H4N)Ln(η3‐C3H5)2] (Ln=Y ( 3 a ), Sc ( 3 b )), which also contained electron‐withdrawing pyridyl‐Cp ligands, were also obtained selectively. Deprotonation of the bulky pyridyl‐Flu ligand (C13H9‐C5H4N) by [Ln(CH2SiMe3)3(thf)2] generated the rare‐earth‐metal–dialkyl complexes, [(η3‐C13H8‐C5H4N)Ln(CH2SiMe3)2(thf)] (Ln=Y ( 4 a ), Sc ( 4 b ), Lu ( 4 c )), in which an unusual asymmetric η3‐allyl bonding mode of Flu moiety was observed. Switching to the bidentate yttrium–trisalkyl complex [Y(CH2C6H4‐o‐NMe2)3], the same reaction conditions afforded the corresponding yttrium bis(aminobenzyl) complex [(η3‐C13H8‐C5H4N)Y(CH2C6H4‐o‐NMe2)2] ( 5 ). Complexes 1 – 5 were fully characterized by 1H and 13C NMR and X‐ray spectroscopy, and by elemental analysis. In the presence of both [Ph3C][B(C6F5)4] and AliBu3, the electron‐donating aminophenyl‐Cp‐based complexes 1 and 2 did not show any activity towards styrene polymerization. In striking contrast, upon activation with [Ph3C][B(C6F5)4] only, the electron‐withdrawing pyridyl‐Cp‐based complexes 3 , in particular scandium complex 3 b , exhibited outstanding activitiy to give perfectly syndiotactic (rrrr >99 %) polystyrene, whereas their bulky pyridyl‐Flu analogues ( 4 and 5 ) in combination with [Ph3C][B(C6F5)4] and AliBu3 displayed much‐lower activity to afford syndiotactic‐enriched polystyrene. 相似文献
7.
Cristina Tejel Dr. M. Pilar del Río Dr. Miguel A. Ciriano Prof. Dr. Eduard J. Reijerse Dr. František Hartl Prof. Stanislav Záliš Dr. Dennis G. H. Hetterscheid Dr. Nearchos Tsichlis i Spithas Bas de Bruin Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(44):11878-11889
Treatment of [Ir(bpa)(cod)]+ complex [ 1 ]+ with a strong base (e.g., tBuO?) led to unexpected double deprotonation to form the anionic [Ir(bpa?2H)(cod)]? species [ 3 ]?, via the mono‐deprotonated neutral amido complex [Ir(bpa?H)(cod)] as an isolable intermediate. A certain degree of aromaticity of the obtained metal–chelate ring may explain the favourable double deprotonation. The rhodium analogue [ 4 ]? was prepared in situ. The new species [M(bpa?2H)(cod)]? (M=Rh, Ir) are best described as two‐electron reduced analogues of the cationic imine complexes [MI(cod)(Py‐CH2‐N?CH‐Py)]+. One‐electron oxidation of [ 3 ]? and [ 4 ]? produced the ligand radical complexes [ 3 ]. and [ 4 ].. Oxygenation of [ 3 ]? with O2 gave the neutral carboxamido complex [Ir(cod)(py‐CH2‐N‐CO‐py)] via the ligand radical complex [ 3 ]. as a detectable intermediate. 相似文献
8.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(4):357-361
PhotoCORMs (photo‐active CO‐releasing molecules) have emerged as a class of CO donors where the CO release process can be triggered upon illumination with light of appropriate wavelength. We have recently reported an Mn‐based photoCORM, namely [MnBr(pbt)(CO)3] [pbt is 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole], where the CO release event can be tracked within cellular milieu by virtue of the emergence of strong blue fluorescence. In pursuit of developing more such trackable photoCORMs, we report herein the syntheses and structural characterization of two MnI–carbonyl complexes, namely fac‐tricarbonylchlorido[2‐(pyridin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′]manganese(I), [MnCl(C12H8N2S)(CO)3], (1), and fac‐tricarbonylchlorido[2‐(quinolin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′]manganese(I), [MnCl(C16H10N2S)(CO)3], (2). In both complexes, the MnI center resides in a distorted octahedral coordination environment. Weak intermolecular C—H…Cl contacts in complex (1) and Cl…S contacts in complex (2) consolidate their extended structures. These complexes also exhibit CO release upon exposure to low‐power broadband visible light. The apparent CO release rates for the two complexes have been measured to compare their CO donating capacity. The fluorogenic 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole and 2‐(quinolin‐2‐yl)‐1,3‐benzothiazole ligands provide a convenient way to track the CO release event through the `turn‐ON' fluorescence which results upon de‐ligation of the ligands from their respective metal centers following CO photorelease. 相似文献
9.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(11):905-910
Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2‐aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)‐ and gold(III)‐mediated cyclizations of thioureas to substituted 2‐aminobenzothiazoles are reported. The single‐crystal X‐ray structures of the thiourea N‐(3‐methoxyphenyl)‐N ′‐(pyridin‐2‐yl)thiourea, C13H13N3OS, and the intermediate metal complexes aquabis[5‐methoxy‐N‐(pyridin‐2‐yl‐κN )‐1,3‐benzothiazol‐2‐amine‐κN 3]copper(II) dinitrate, [Cu(C13H11N3OS)2(H2O)](NO3)2, and bis{2‐[(5‐methoxy‐1,3‐benzothiazol‐2‐yl)amino]pyridin‐1‐ium} dichloridogold(I) chloride monohydrate, (C13H12N3OS)2[AuCl2]Cl·H2O, are reported. The copper complex exhibits a distorted trigonal–bipyramidal geometry, with direct metal‐to‐benzothiazole‐ligand coordination, while the gold complex is a salt containing the protonated uncoordinated benzothiazole, and offers evidence that metal reduction (in this case, AuIII to AuI) is required for the cyclization to proceed. As such, this study provides further mechanistic insight into the role of the metal cations in these transformations. 相似文献
10.
《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
11.
Edward D. Cross Kristen L. MacDonald Robert McDonald Matthias Bierenstiel 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):23-27
The reaction of dichlorido(cod)palladium(II) (cod = 1,5‐cyclooctadiene) with 2‐(benzylsulfanyl)aniline followed by heating in N,N‐dimethylformamide (DMF) produces the linear trinuclear Pd3 complex bis(μ2‐1,3‐benzothiazole‐2‐thiolato)bis[μ2‐2‐(benzylsulfanyl)anilinido]dichloridotripalladium(II) N,N‐dimethylformamide disolvate, [Pd3(C7H4NS2)2(C13H12NS)2Cl2]·2C3H7NO. The molecule has symmetry and a Pd...Pd separation of 3.2012 (4) Å. The outer PdII atoms have a square‐planar geometry formed by an N,S‐chelating 2‐(benzylsulfanyl)anilinide ligand, a chloride ligand and the thiolate S atom of a bridging 1,3‐benzothiazole‐2‐thiolate ligand, while the central PdII core shows an all N‐coordinated square‐planar geometry. The geometry is perfectly planar within the PdN4 core and the N—Pd—N bond angles differ significantly [84.72 (15)° for the N atoms of ligands coordinated to the same outer Pd atom and 95.28 (15)° for the N atoms of ligands coordinated to different outer Pd atoms]. This trinuclear Pd3 complex is the first example of one in which 1,3‐benzothiazole‐2‐thiolate ligands are only N‐coordinated to one Pd centre. The 1,3‐benzothiazole‐2‐thiolate ligands were formed in situ from 2‐(benzylsulfanyl)aniline. 相似文献
12.
A series of new heteroleptic iridium(III) complexes [Ir(C?N)2(N?N)]PF6 ( 1 ‐ 6 ) (each with two cyclometalating C?N ligands and one neutral N?N ancillary ligand, where C?N = 2‐phenylpyridine (ppy), 5‐methyl‐2‐(4‐fluoro)phenylpyridine (F‐mppy), and N?N = 2,2′‐dipyridyl (bpy), 1,10‐phenanthroline (phen), 4,4′‐diphenyl‐2,2′‐dipyridy (dphphen) were found to have rich photophysical properties. Theoretical calculations are employed for studying the photophysical and electrochemical properties. All complexes are investigated using density functional theory. Excited singlet and triplet states are examined using time‐dependent density functional theory. The low‐lying excited‐state geometries are optimized at the ab initio configuration interaction singles level. Then, the excited‐state properties are investigated in detail, including absorption and emission properties, photoactivation processes. The excited state of complexes is complicated and contains triplet metal‐to‐ligand charge transfer, triplet ligand‐to‐ligand charge transfer simultaneously. Importantly, the absorption spectra and emission maxima can be tuned significantly by changing the N?N ligands and C?N ligands. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
13.
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
14.
Benjamin J. Hellmann Ajay Venugopal Dr. Andreas Mix Dr. Beate Neumann Hans‐Georg Stammler Dr. Alexander Willner Dr. Tanja Pape Alexander Hepp Dr. Norbert W. Mitzel Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(43):11701-11709
The reaction of the donor‐functionalised N,N‐bis(2‐{pyrid‐2‐yl}ethyl)hydroxylamine and [LnCp3] (Cp=cyclopentadiene) resulted in the formation of bis(cyclopentadienyl) hydroxylaminato rare‐earth metal complexes of the general constitution [Ln(C5H5)2{ON(C2H4‐o‐Py)2}] (Py= pyridyl) with Ln=Lu ( 1 ), Y ( 2 ), Ho ( 3 ), Sm ( 4 ), Nd ( 5 ), Pr ( 6 ), La ( 7 ). These compounds were characterised by elemental analysis, mass spectrometry, NMR spectroscopy (for compounds 1 , 2 , 4 and 7 ) and single‐crystal X‐ray diffraction experiments. The complexes exhibit three different aggregation modes and binding motifs in the solid state. The late rare‐earth metal atoms (Lu, Y, Ho and Sm) form monomeric complexes of the formula [Ln(C5H5)2{η2‐ON(C2H4‐η1‐o‐Py)(C2H4‐o‐Py)}] ( 1 – 4 , respectively), in which one of the pyridyl nitrogen donor atoms is bonded to the metal atom in addition to the side‐on coordinating hydroxylaminato unit. The larger Nd3+ and Pr3+ ions in 5 and 6 make the hydroxylaminato unit capable of dimerising through the oxygen atoms. This leads to the dimeric complexes [(Ln(C5H5)2{μ‐η1:η2‐ON(C2H4‐o‐Py)2})2] without metal–pyridine bonds. Compound 7 exhibits a dimeric coordination mode similar to the complexes 5 and 6 , but, in addition, two pyridyl functions coordinate to the lanthanum atoms leading to the [(La(C5H5)2{ON(C2H4‐o‐Py)}{μ‐η1:η2‐ON(C2H4‐η1‐o‐Py)})2] complex. The aggregation trend is directly related to the size of the metal ions. The complexes with coordinative pyridine–metal bonds show highly dynamic behaviour in solution. The two pyridine nitrogen atoms rapidly change their coordination to the metal atom at ambient temperature. Variable‐temperature (VT) NMR experiments showed that this dynamic exchange can be frozen on the NMR timescale. 相似文献
15.
Lewis C. Wilkins Youngmin Kim Elishua D. Litle Franois P. Gabbaï 《Angewandte Chemie (International ed. in English)》2019,58(50):18266-18270
Controlling the reactivity of transition metals using secondary, σ‐accepting ligands is an active area of investigation that is impacting molecular catalysis. Herein we describe the phosphine gold complexes [(o‐Ph2P(C6H4)Acr)AuCl]+ ([ 3 ]+; Acr=9‐N‐methylacridinium) and [(o‐Ph2P(C6H4)Xan)AuCl]+ ([ 4 ]+; Xan=9‐xanthylium) where the electrophilic carbenium moiety is juxtaposed with the metal atom. While only weak interactions occur between the gold atom and the carbenium moiety of these complexes, the more Lewis acidic complex [ 4 ]+ readily reacts with chloride to afford a trivalent phosphine gold dichloride derivative ( 7 ) in which the metal atom is covalently bound to the former carbocationic center. This anion‐induced AuI/AuIII oxidation is accompanied by a conversion of the Lewis acidic carbocationic center in [ 4 ]+ into an X‐type ligand in 7 . We conclude that the carbenium moiety of this complex acts as a latent Z‐type ligand poised to increase the Lewis acidity of the gold center, a notion supported by the carbophilic reactivity of these complexes. 相似文献
16.
Adam Neuba Dr. Sonja Herres‐Pawlis Oliver Seewald Janna Börner Andreas J. Heuwing Ulrich Flörke Prof. Dr. Gerald Henkel 《无机化学与普通化学杂志》2010,636(15):2641-2649
The transition metal complexes with the ligand 1,3‐bis(N,N,N′,N′‐tetramethylguanidino)propane (btmgp), [Mn(btmgp)Br2] ( 1 ), [Co(btmgp)Cl2] ( 2 ), [Ni(btmgp)I2] ( 3 ), [Zn(btmgp)Cl2] ( 4 ), [Zn(btmgp)(O2CCH3)2] ( 5 ), [Cd(btmgp)Cl2] ( 6 ), [Hg(btmgp)Cl2] ( 7 ) and [Ag2(btmgp)2][ClO4]2·2MeCN ( 8 ), were prepared and characterised for the first time. The stoichiometric reaction of the corresponding water‐free metal salts with the ligand btmgp in dry MeCN or THF resulted in the straightforward formation of the mononuclear complexes 1 – 7 and the binuclear complex 8 . In complexes with MII the metal ion shows a distorted tetrahedral coordination whereas in 8 , the coordination of the MI ion is almost linear. The coordination behavior of btmgp and resulting structural parameters of the corresponding complexes were discussed in an comparative approach together with already described complexes of btmgp and the bisguanidine ligand N1,N2‐bis(1,3‐dimethylimidazolidin‐2‐ylidene)‐ethane‐1,2‐diamine (DMEG2e), respectively. 相似文献
17.
Lanthanide(II) Complexes Supported by N,O‐Donor Tripodal Ligands: Synthesis,Structure, and Ligand‐Dependent Redox Behavior 下载免费PDF全文
Julie Andrez Dr. Gülay Bozoklu Dr. Grégory Nocton Dr. Jacques Pécaut Dr. Rosario Scopelliti Dr. Lionel Dubois Dr. Marinella Mazzanti 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15188-15200
The preparation and characterization of a series of complexes of the Yb and Eu cations in the oxidation state II and III with the tetradentate N,O‐donor tripodal ligands (tris(2‐pyridylmethyl)amine (TPA), BPA? (HBPA=bis(2‐pyridylmethyl)(2‐hydroxybenzyl)amine), BPPA? (HBPPA=bis(2‐pyridylmethyl)(3.5‐di‐tert‐butyl‐2‐hydroxybenzyl)amine), and MPA2? (H2MPA=(2‐pyridylmethyl)bis(3.5‐di‐tert‐butyl‐2‐hydroxybenzyl)amine) is reported. The X‐ray crystal structures of the heteroleptic Ln2+ complexes [Ln(TPA)I2] (Ln=Eu, Yb) and [Yb(BPA)I(CH3CN)]2, of the Ln2+ homoleptic [Ln(TPA)2]I2 (Ln=Sm, Eu, Yb) and [Eu(BPA)2] complexes, and of the Ln3+ [Eu(BPPA)2]OTf and [Yb(MPA)2K(dme)2] (dme=dimethoxyethane) complexes have been determined. Cyclic voltammetry studies carried out on the bis‐ligand complexes of Eu3+ and Yb3+ show that the metal center reduction occurs at significantly lower potentials for the BPA? ligand as compared with the TPA ligand. This suggests that the more electron‐rich character of the BPA? ligand results in a higher reducing character of the lanthanide complexes of BPA? compared with those of TPA. The important differences in the stability and reactivity of the investigated complexes are probably due to the observed difference in redox potential. Preliminary reactivity studies show that whereas the bis‐TPA complexes of Eu2+ and Yb2+ do not show any reactivity with heteroallenes, the [Eu(BPA)2] complex reduces CS2 to afford the first example of a lanthanide trithiocarbonate complex. 相似文献
18.
Tunable Fluorophores Based on 2‐(N‐Arylimino)pyrrolyl Chelates of Diphenylboron: Synthesis,Structure, Photophysical Characterization,and Application in OLEDs 下载免费PDF全文
Dr. D. Suresh Patrícia S. Lopes Bruno Ferreira Cláudia A. Figueira Dr. Clara S. B. Gomes Dr. Pedro T. Gomes Dr. Roberto E. Di Paolo Prof. António L. Maçanita Dr. M. Teresa Duarte Dr. Ana Charas Dr. Jorge Morgado Prof. Maria José Calhorda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(14):4126-4140
Reactions of 2‐(N‐arylimino)pyrroles (HNC4H3C(H)?N‐Ar) with triphenylboron (BPh3) in boiling toluene afford the respective highly emissive N,N′‐boron chelate complexes, [BPh2{κ2N,N′‐NC4H3C(H)?N‐Ar}] (Ar=C6H5 ( 12 ), 2,6‐Me2‐C6H3 ( 13 ), 2,6‐iPr2‐C6H3 ( 14 ), 4‐OMe‐C6H4 ( 15 ), 3,4‐Me2‐C6H3 ( 16 ), 4‐F‐C6H4 ( 17 ), 4‐NO2‐C6H4 ( 18 ), 4‐CN‐C6H4 ( 19 ), 3,4,5‐F3‐C6H2 ( 20 ), and C6F5 ( 21 )) in moderate to high yields. The photophysical properties of these new boron complexes largely depend on the substituents present on the aryl rings of their N‐arylimino moieties. The complexes bearing electron‐withdrawing aniline substituents 17 – 20 show more intense (e.g., ?f=0.71 for Ar=4‐CN‐C6H4 ( 19 ) in THF), higher‐energy (blue) fluorescent emission compared to those bearing electron‐donating substituents, for which the emission is redshifted at the expense of lower quantum yields (?f=0.13 and 0.14 for Ar=4‐OMe‐C6H4 ( 15 ) and 3,4‐Me2‐C6H3 ( 16 ), respectively, in THF). The presence of substituents bulkier than a hydrogen atom at the 2,6‐positions of the aryl groups strongly restricts rotation of this moiety towards coplanarity with the iminopyrrolyl ligand framework, inducing a shift in the emission to the violet region (λmax=410–465 nm) and a significant decrease in quantum yield (?f=0.005, 0.023, and 0.20 for Ar=2,6‐Me2‐C6H3 ( 13 ), 2,6‐iPr2‐C6H3 ( 14 ), and C6F5 ( 21 ), respectively, in THF), even when electron‐withdrawing groups are also present. Density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations have indicated that the excited singlet state has a planar aryliminopyrrolyl ligand, except when prevented by steric hindrance (ortho substituents). Calculated absorption maxima reproduce the experimental values, but the error is higher for the emission wavelengths. Organic light‐emitting diodes (OLEDs) have been fabricated with the new boron complexes, with luminances of the order of 3000 cd m?2 being achieved for a green‐emitting device. 相似文献
19.
Homoleptic Two‐Coordinate Silylamido Complexes of Chromium(I), Manganese(I), and Cobalt(I) 下载免费PDF全文
Dr. C. Gunnar Werncke Dr. Elizaveta Suturina Philip C. Bunting Dr. Laure Vendier Prof. Jeffrey R. Long Prof. Dr. Mihail Atanasov Prof. Dr. Frank Neese Dr. Sylviane Sabo‐Etienne Dr. Sébastien Bontemps 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(5):1668-1674
Anionic two‐coordinate complexes of first‐row transition‐metal(I) centres are rare molecules that are expected to reveal new magnetic properties and reactivity. Recently, we demonstrated that a N(SiMe3)2? ligand set, which is unable to prevent dimerisation or extraneous ligand coordination at the +2 oxidation state of iron, was nonetheless able to stabilise anionic two‐coordinate FeI complexes even in the presence of a Lewis base. We now report analogous CrI and CoI complexes with exclusively this amido ligand and the isolation of a [MnI{N(SiMe3)2}2]22? dimer that features a Mn?Mn bond. Additionally, by increasing the steric hindrance of the ligand set, the two‐coordinate complex [MnI{N(Dipp)(SiMe3)}2]? was isolated (Dipp=2,6‐iPr2‐C6H3). Characterisation of these compounds by using X‐ray crystallography, NMR spectroscopy, and magnetic susceptibility measurements is provided along with ligand‐field analysis based on CASSCF/NEVPT2 ab initio calculations. 相似文献
20.
Prof. Javier A. Cabeza Dr. José M. Fernández‐Colinas Dr. Pablo García‐Álvarez Dr. Enrique Pérez‐Carreño Dr. Vanessa Pruneda Dr. Juan F. Van der Maelen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(28):9251-9260
The C‐alkyl groups of cationic triruthenium cluster complexes of the type [Ru3(μ‐H)(μ‐κ2N1,C2 ‐L)(CO)10]+ (HL represents a generic C‐alkyl‐N‐methylpyrazium species) have been deprotonated to give kinetic products that contain unprecedented C‐alkylidene derivatives and maintain the original edge‐bridged decacarbonyl structure. When the starting complexes contain various C‐alkyl groups, the selectivity of these deprotonation reactions is related to the atomic charges of the alkyl H atoms, as suggested by DFT/natural‐bond orbital (NBO) calculations. Three additional electronic properties of the C‐alkyl C? H bonds have also been found to correlate with the experimental regioselectivity because, in all cases, the deprotonated C? H bond has the smallest electron density at the bond critical point, the greatest Laplacian of the electron density at the bond critical point, and the greatest total energy density ratio at the bond critical point (computed by using the quantum theory of atoms in molecules, QTAIM). The kinetic decacarbonyl products evolve, under appropriate reaction conditions that depend upon the position of the C‐alkylidene group in the heterocyclic ring, toward face‐capped nonacarbonyl derivatives (thermodynamic products). The position of the C‐alkylidene group in the heterocyclic ring determines the distribution of single and double bonds within the ligand ring, which strongly affects the stability of the neutral decacarbonyl complexes and the way these ligands coordinate to the metal atoms in the nonacarbonyl products. The mechanisms of these decacarbonylation processes have been investigated by DFT methods, which have rationalized the structures observed for the final products and have shed light on the different kinetic and thermodynamic stabilities of the reaction intermediates, thus explaining the reaction conditions experimentally required by each transformation. 相似文献