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1.
Esben P. K. Olsen Prof. Dr. Robert Madsen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(50):16023-16029
A new iridium ‐ catalyzed reaction in which molecular hydrogen and carbon monoxide are cleaved from primary alcohols in the absence of any stoichiometric additives has been developed. The dehydrogenative decarbonylation was achieved with a catalyst generated in situ from [Ir(coe)2Cl]2 (coe=cyclooctene) and racemic 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (rac‐BINAP) in a mesitylene solution saturated with water. A catalytic amount of lithium chloride was also added to improve the catalyst turnover. The reaction has been applied to a variety of primary alcohols and gives rise to products in good to excellent yields. Ethers, esters, imides, and aryl halides are stable under the reaction conditions, whereas olefins are partially saturated. The reaction is believed to proceed by two consecutive organometallic transformations that are catalyzed by the same iridium(I)–BINAP species. First, dehydrogenation of the primary alcohol to the corresponding aldehyde takes place, which is then followed by decarbonylation to the product with one less carbon atom. 相似文献
2.
Jia‐Geng Liu Jing‐Jing Nie Duan‐Jun Xu Yuan‐Zhi Xu Jing‐Yun Wu Michael Y. Chiang 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):354-355
The title complex, [CuCl2(C6H6N4S2)], has a flattened tetrahedral coordination. The CuII atom is located on a twofold rotation axis and is coordinated by two N atoms from a chelating 2,2′‐diamino‐4,4′‐bi‐1,3‐thiazole ligand and by two Cl atoms. Intramolecular hydrogen bonding exists between the amino groups of the 2,2′‐diamino‐4,4′‐bi‐1,3‐thiazole ligand and the Cl atoms. The intermolecular separation of 3.425 (1) Å between parallel bithiazole rings suggests there is a π–π interaction between them. 相似文献
3.
Synthesis, structure, and reactivity of carboranylamidinate‐based half‐sandwich iridium and rhodium complexes are reported for the first time. Treatment of dimeric metal complexes [{Cp*M(μ‐Cl)Cl}2] (M=Ir, Rh; Cp*=η5‐C5Me5) with a solution of one equivalent of nBuLi and a carboranylamidine produces 18‐electron complexes [Cp*IrCl(CabN‐DIC)] ( 1 a ; CabN‐DIC=[iPrN?C(closo‐1,2‐C2B10H10)(NHiPr)]), [Cp*RhCl(CabN‐DIC)] ( 1 b ), and [Cp*RhCl(CabN‐DCC)] ( 1 c ; CabN‐DCC=[CyN?C(closo‐1,2‐C2B10H10)(NHCy)]). A series of 16‐electron half‐sandwich Ir and Rh complexes [Cp*Ir(CabN′‐DIC)] ( 2 a ; CabN′‐DIC=[iPrN?C(closo‐1,2‐C2B10H10)(NiPr)]), [Cp*Ir(CabN′‐DCC)] ( 2 b , CabN′‐DCC=[CyN?C(closo‐1,2‐C2B10H10)(NCy)]), and [Cp*Rh(CabN′‐DIC)] ( 2 c ) is also obtained when an excess of nBuLi is used. The unexpected products [Cp*M(CabN,S‐DIC)], [Cp*M(CabN,S‐DCC)] (M=Ir 3 a , 3 b ; Rh 3 c , 3 d ), formed through BH activation, are obtained by reaction of [{Cp*MCl2}2] with carboranylamidinate sulfides [RN?C(closo‐1,2‐C2B10H10)(NHR)]S? (R=iPr, Cy), which can be prepared by inserting sulfur into the C? Li bond of lithium carboranylamidinates. Iridium complex 1 a shows catalytic activities of up to 2.69×106 gPNB ${{\rm{mol}}_{{\rm{Ir}}}^{ - {\rm{1}}} }Synthesis, structure, and reactivity of carboranylamidinate-based half-sandwich iridium and rhodium complexes are reported for the first time. Treatment of dimeric metal complexes [{Cp*M(μ-Cl)Cl}(2)] (M = Ir, Rh; Cp* = η(5)-C(5)Me(5)) with a solution of one equivalent of nBuLi and a carboranylamidine produces 18-electron complexes [Cp*IrCl(Cab(N)-DIC)] (1?a; Cab(N)-DIC = [iPrN=C(closo-1,2-C(2)B(10)H(10))(NHiPr)]), [Cp*RhCl(Cab(N)-DIC)] (1?b), and [Cp*RhCl(Cab(N)-DCC)] (1?c; Cab(N)-DCC = [CyN=C(closo-1,2-C(2)B(10)H(10))(NHCy)]). A series of 16-electron half-sandwich Ir and Rh complexes [Cp*Ir(Cab(N')-DIC)] (2?a; Cab(N')-DIC = [iPrN=C(closo-1,2-C(2)B(10)H(10))(NiPr)]), [Cp*Ir(Cab(N')-DCC)] (2?b, Cab(N')-DCC = [CyN=C(closo-1,2-C(2)B(10)H(10)(NCy)]), and [Cp*Rh(Cab(N')-DIC)] (2?c) is also obtained when an excess of nBuLi is used. The unexpected products [Cp*M(Cab(N,S)-DIC)], [Cp*M(Cab(N,S)-DCC)] (M = Ir 3?a, 3?b; Rh 3?c, 3?d), formed through BH activation, are obtained by reaction of [{Cp*MCl(2)}(2)] with carboranylamidinate sulfides [RN=C(closo-1,2-C(2)B(10)H(10))(NHR)]S(-) (R = iPr, Cy), which can be prepared by inserting sulfur into the C-Li bond of lithium carboranylamidinates. Iridium complex 1?a shows catalytic activities of up to 2.69×10(6) g(PNB) mol(Ir)(-1) h(-1) for the polymerization of norbornene in the presence of methylaluminoxane (MAO) as cocatalyst. Catalytic activities and the molecular weight of polynorbornene (PNB) were investigated under various reaction conditions. All complexes were fully characterized by elemental analysis and IR and NMR spectroscopy; the structures of 1?a-c, 2?a, b; and 3?a, b, d were further confirmed by single crystal X-ray diffraction. 相似文献
4.
Dr. Zhen‐Tao Yu Yong‐Jun Yuan Jian‐Guang Cai Prof. Dr. Zhi‐Gang Zou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(4):1303-1310
Two new charge‐neutral iridium complexes, [Ir(tfm‐ppy)2(N,N′‐diisopropyl‐benzamidinate)] ( 1 ) and [Ir(tfm‐ppy)2(N,N′‐diisopropyl‐4‐diethylamino‐3,5‐dimethyl‐benzamidinate)] ( 2 ) (tfm‐ppy=4‐trifluoromethyl‐2‐phenylpyridine) containing an amidinate ligand and two phenylpyridine ligands were designed and characterised. The photophysical properties, electrochemical behaviours and emission quenching properties of these species were investigated. In concert with the cobalt catalyst [Co(bpy)3]2+, members of this new class of iridium complexes enable the photocatalytic generation of hydrogen from mixed aqueous solutions via an oxidative quenching pathway and display long‐term photostability under constant illumination over 72 h; one of these species achieved a relatively high turnover number of 1880 during this time period. In the case of complex 1 , the three‐component homogeneous photocatalytic system proved to be more efficient than a related system containing a charged complex, [Ir(tfm‐ppy)2(dtb‐bpy)]+ ( 3 , dtb‐bpy=4,4′‐di‐tert‐butyl‐2,2′‐dipyridyl). In combination with a rhodium complex as a water reduction catalyst, the performances of the systems using both complexes were also evaluated, and these systems exhibited a more efficient catalytic propensity for water splitting than did the cobalt‐based systems that have been studied previously. 相似文献
5.
Dharmalingam Sivanesan Hyung Min Kim Yoon Sungho 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(6):584-587
The title complex, [Rh(C10H15)Cl(C14H12N2O4)]Cl·2C4H5NO3, has been synthesized by a substitution reaction of the precursor [bis(2,5‐dioxopyrrolidin‐1‐yl) 2,2′‐bipyridine‐4,4′‐dicarboxylate]chlorido(pentamethylcyclopentadienyl)rhodium(III) chloride with NaOCH3. The RhIII cation is located in an RhC5N2Cl eight‐coordinated environment. In the crystal, 1‐hydroxypyrrolidine‐2,5‐dione (NHS) solvent molecules form strong hydrogen bonds with the Cl− counter‐anions in the lattice and weak hydrogen bonds with the pentamethylcyclopentadienyl (Cp*) ligands. Hydrogen bonding between the Cp* ligands, the NHS solvent molecules and the Cl− counter‐anions form links in a V‐shaped chain of RhIII complex cations along the c axis. Weak hydrogen bonds between the dimethyl 2,2′‐bipyridine‐4,4′‐dicarboxylate ligands and the Cl− counter‐anions connect the components into a supramolecular three‐dimensional network. The synthetic route to the dimethyl 2,2′‐bipyridine‐4,4′‐dicarboxylate‐containing rhodium complex from the [bis(2,5‐dioxopyrrolidin‐1‐yl) 2,2′‐bipyridine‐4,4′‐dicarboxylate]rhodium(III) precursor may be applied to link Rh catalysts to the surface of electrodes. 相似文献
6.
Zheng‐Liang Lü Zhi‐Liang Liu De‐Qing Zhang 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(3):m147-m150
In the two isomorphous title compounds, viz. tris[2,2′‐bi(4,5‐dihydro‐1,3‐oxazole)‐κ2N,N′]copper(II) diperchlorate, [Cu(C6H8N2O2)3](ClO4)2, (I), and tris[2,2′‐bi(4,5‐dihydro‐1,3‐oxazole)‐κ2N,N′]nickel(II) diperchlorate, [Ni(C6H8N2O2)3](ClO4)2, (II), the MII ions each have a distorted octahedral coordination geometry formed via six N atoms from three 2,2′‐bioxazoline ligands. For each ligand, the two five‐membered rings are nearly coplanar. It is noteworthy that the Jahn–Teller effect is stronger in (I) than in (II). The three‐dimensional supramolecular structures of (I) and (II) are formed via weak hydrogen‐bonding interactions between O atoms from perchlorate anions and H atoms from 2,2′‐bioxazoline ligands. 相似文献
7.
Ai‐Guo Li Qi‐Kui Liu Yan‐An Li Zhi‐Xian Liu Yu‐Bin Dong 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):37-42
A new 2,2′‐bi‐1H‐benzimidazole bridging organic ligand, namely 1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole, C26H20N6, L or (I), has been synthesized and used to create three new one‐dimensional coordination polymers, viz.catena‐poly[[dichloridomercury(II)]‐μ‐1,1′‐bis(pyridin‐4‐ylmethyl)‐2,2′‐bi‐1H‐benzimidazole], [HgCl2(C26H20N6)]n, (II), and the bromido, [HgBr2(C26H20N6)]n, (III), and iodido, [HgI2(C26H20N6)]n, (IV), analogues. Free ligand L crystallizes with two symmetry‐independent half‐molecules in the asymmetric unit and each L molecule resides on a crytallographic inversion centre. In structures (II)–(IV), the L ligand is also positioned on a crystallographic inversion centre, whereas the Hg centre resides on a crystallographic twofold axis. Compound (I) adopts an anti conformation in the solid state and forms a two‐dimensional network in the crystallographic bc plane viaπ–π and C—H...π interactions. The three HgII coordination complexes, (II)–(IV), have one‐dimensional zigzag chains composed of L and HgX2 (X = Cl, Br and I), and the HgII centres are in a distorted tetrahedral [HgX2N2] coordination geometry. Complexes (III) and (IV) are isomorphous, whereas complex (II) displays an interesting conformational difference from the others, i.e. a twist in the flexible bridging ligand. 相似文献
8.
Three new hetero‐bischelated rhodium (III) complexes of cis‐[Rh(PA)(L)Cl2]Cl (where PA = phenylpyridin‐2‐ylmethylene‐amine; L = 2,2′‐bipyridine, 2,2′‐dipyridylamine and 1,10‐phenanthroline) have been successfully prepared and characterized. Each complex shows high intensity bands in the UV region, and these are assigned to spin‐allowed π‐π* transitions. The medium‐intensity absorption band profile in the lower energy region can be explained by convolution of spin‐allowed CT and d‐d* transitions. The emission spectra at low temperature (77 K) of these complexes in EtOH/MeOH (4:1 v/v) are virtually identical. They all exhibit a broad, symmetric, and structureless red emission with a microsecond lifetime and hence are assigned as the d‐d* phosphorescence. 相似文献
9.
trans‐(Cl)‐[Ru(5,5′‐diamide‐2,2′‐bipyridine)(CO)2Cl2]: Synthesis,Structure, and Photocatalytic CO2 Reduction Activity
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Dr. Yusuke Kuramochi Kyohei Fukaya Makoto Yoshida Prof. Hitoshi Ishida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10049-10060
A series of trans‐(Cl)‐[Ru(L)(CO)2Cl2]‐type complexes, in which the ligands L are 2,2′‐bipyridyl derivatives with amide groups at the 5,5′‐positions, are synthesized. The C‐connected amide group bound to the bipyridyl ligand through the carbonyl carbon atom is twisted with respect to the bipyridyl plane, whereas the N‐connected amide group is in the plane. DFT calculations reveal that the twisted structure of the C‐connected amide group raises the level of the LUMO, which results in a negative shift of the first reduction potential (Ep) of the ruthenium complex. The catalytic abilities for CO2 reduction are evaluated in photoreactions (λ>400 nm) with the ruthenium complexes (the catalyst), [Ru(bpy)3]2+ (bpy=2,2′‐bipyridine; the photosensitizer), and 1‐benzyl‐1,4‐dihydronicotinamide (the electron donor) in CO2‐saturated N,N‐dimethylacetamide/water. The logarithm of the turnover frequency increases by shifting Ep a negative value until it reaches the reduction potential of the photosensitizer. 相似文献
10.
Dr. Gabriel Menendez Rodriguez Dr. Francesco Zaccaria Leonardo Tensi Prof. Cristiano Zuccaccia Prof. Paola Belanzoni Prof. Alceo Macchioni 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(6):2050-2064
The degradation pathways of highly active [Cp*Ir(κ2-N,N-R-pica)Cl] catalysts (pica=picolinamidate; 1 R=H, 2 R=Me) for formic acid (FA) dehydrogenation were investigated by NMR spectroscopy and DFT calculations. Under acidic conditions (1 equiv. of HNO3), 2 undergoes partial protonation of the amide moiety, inducing rapid κ2-N,N to κ2-N,O ligand isomerization. Consistently, DFT modeling on the simpler complex 1 showed that the κ2-N,N key intermediate of FA dehydrogenation ( INH ), bearing a N-protonated pica, can easily transform into the κ2-N,O analogue ( INH2 ; ΔG≠≈11 kcal mol−1, ΔG ≈−5 kcal mol−1). Intramolecular hydrogen liberation from INH2 is predicted to be rather prohibitive (ΔG≠≈26 kcal mol−1, ΔG≈23 kcal mol−1), indicating that FA dehydrogenation should involve mostly κ2-N,N intermediates, at least at relatively high pH. Under FA dehydrogenation conditions, 2 was progressively consumed, and the vast majority of the Ir centers (58 %) were eventually found in the form of Cp*-complexes with a pyridine-amine ligand. This likely derived from hydrogenation of the pyridine-carboxiamide via a hemiaminal intermediate, which could also be detected. Clear evidence for ligand hydrogenation being the main degradation pathway also for 1 was obtained, as further confirmed by spectroscopic and catalytic tests on the independently synthesized degradation product 1 c . DFT calculations confirmed that this side reaction is kinetically and thermodynamically accessible. 相似文献
11.
Syntheses,Spectroscopic, Electrochemical,and Third‐Order Nonlinear Optical Studies of a Hybrid Tris{ruthenium(alkynyl)/(2‐phenylpyridine)}iridium Complex
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Huajian Zhao Dr. Peter V. Simpson Adam Barlow Dr. Graeme J. Moxey Dr. Mahbod Morshedi Nivya Roy Prof. Reji Philip Prof. Chi Zhang Dr. Marie P. Cifuentes Prof. Mark G. Humphrey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11843-11854
The synthesis of fac‐[Ir{N,C1′‐(2,2′‐NC5H4C6H3‐5′‐C?C‐1‐C6H2‐3,5‐Et2‐4‐C?CC6H4‐4‐C?CH)}3] ( 10 ), which bears pendant ethynyl groups, and its reaction with [RuCl(dppe)2]PF6 to afford the heterobimetallic complex fac‐[Ir{N,C1′‐(2,2′‐NC5H4C6H3‐5′‐C?C‐1‐C6H2‐3,5‐Et2‐4‐C?CC6H4‐4‐C?C‐trans‐[RuCl(dppe)2])}3] ( 11 ) is described. Complex 10 is available from the two‐step formation of iodo‐functionalized fac‐tris[2‐(4‐iodophenyl)pyridine]iridium(III) ( 6 ), followed by ligand‐centered palladium‐catalyzed coupling and desilylation reactions. Structural studies of tetrakis[2‐(4‐iodophenyl)pyridine‐N,C1′](μ‐dichloro)diiridium 5 , 6 , fac‐[Ir{N,C1′‐(2,2′‐NC5H4C6H3‐5′‐C?C‐1‐C6H2‐3,5‐Et2‐4‐C?CH)}3] ( 8 ), and 10 confirm ligand‐centered derivatization of the tris(2‐phenylpyridine)iridium unit. Electrochemical studies reveal two ( 5 ) or one ( 6 – 10 ) Ir‐centered oxidations for which the potential is sensitive to functionalization at the phenylpyridine groups but relatively insensitive to more remote derivatization. Compound 11 undergoes sequential Ru‐centered and Ir‐centered oxidation, with the potential of the latter significantly more positive than that of Ir(N,C′‐NC5H4‐2‐C6H4‐2)3. Ligand‐centered π–π* transitions characteristic of the Ir(N,C′‐NC5H4‐2‐C6H4‐2)3 unit red‐shift and gain in intensity following the iodo and alkynyl incorporation. Spectroelectrochemical studies of 6 , 7 , 9 , and 11 reveal the appearance in each case of new low‐energy LMCT bands following formal IrIII/IV oxidation preceded, in the case of 11 , by the appearance of a low‐energy LMCT band associated with the formal RuII/III oxidation process. Emission maxima of 6 – 10 reveal a red‐shift upon alkynyl group introduction and arylalkynyl π‐system lengthening; this process is quenched upon incorporation of the ligated ruthenium moiety on proceeding to 11 . Third‐order nonlinear optical studies of 11 were undertaken at the benchmark wavelengths of 800 nm (fs pulses) and 532 nm (ns pulses), the results from the former suggesting a dominant contribution from two‐photon absorption, and results from the latter being consistent with primarily excited‐state absorption. 相似文献
12.
Liliana V. Lukashuk Andrey B. Lysenko Harald Krautscheid Konstantin V. Domasevitch 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(12):m378-m383
Poly[bis(3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium) γ‐octamolybdate(VI) dihydrate], {(C10H16N4)2[Mo8O26]·2H2O}n, (I), and bis(3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium) α‐dodecamolybdo(VI)silicate tetrahydrate, (C10H16N4)2[SiMo12O40]·4H2O, (II), display intense hydrogen bonding between the cationic pyrazolium species and the metal oxide anions. In (I), the asymmetric unit contains half a centrosymmetric γ‐type [Mo8O26]4− anion, which produces a one‐dimensional polymeric chain by corner‐sharing, one cation and one water molecule. Three‐centre bonding with 3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium, denoted [H2Me4bpz]2+ [N...O = 2.770 (4)–3.146 (4) Å], generates two‐dimensional layers that are further linked by hydrogen bonds involving water molecules [O...O = 2.902 (4) and 3.010 (4) Å]. In (II), each of the four independent [H2Me4bpz]2+ cations lies across a twofold axis. They link layers of [SiMo12O40]4− anions into a three‐dimensional framework, and the preferred sites for pyrazolium/anion hydrogen bonding are the terminal oxide atoms [N...O = 2.866 (6)–2.999 (6) Å], while anion/aqua interactions occur preferentially viaμ2‐O sites [O...O = 2.910 (6)–3.151 (6) Å]. 相似文献
13.
Yasunori Muranishi Yue Wang Mamiko Odoko Nobuo Okabe 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):m307-m310
In the three title complexes, namely (2,2′‐biquinoline‐κ2N,N′)dichloropalladium(II), [PdCl2(C18H12N2)], (I), and the corresponding copper(II), [CuCl2(C18H12N2)], (II), and zinc(II) complexes, [ZnCl2(C18H12N2)], (III), each metal atom is four‐coordinate and bonded by two N atoms of a 2,2′‐biquinoline molecule and two Cl atoms. The PdII atom has a distorted cis‐square‐planar coordination geometry, whereas the CuII and ZnII atoms both have a distorted tetrahedral geometry. The dihedral angles between the N—M—N and Cl—M—Cl planes are 14.53 (13), 65.42 (15) and 85.19 (9)° for (I), (II) and (III), respectively. The structure of (II) has twofold imposed symmetry. 相似文献
14.
Study of the Bonding Modes of Di‐2‐pyridyl ketoxime Ligand towards Ruthenium,Rhodium and Iridium Half Sandwich Complexes
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The bonding modes of the ligand di‐2‐pyridyl ketoxime towards half‐sandwich arene ruthenium, Cp*Rh and Cp*Ir complexes were investigated. Di‐2‐pyridyl ketoxime {pyC(py)NOH} react with metal precursor [Cp*IrCl2]2 to give cationic oxime complexes of the general formula [Cp*Ir{pyC(py)NOH}Cl]PF6 ( 1a ) and [Cp*Ir{pyC(py)NOH}Cl]PF6 ( 1b ), for which two coordination isomers were observed by NMR spectroscopy. The molecular structures of the complexes revealed that in the major isomer the oxime nitrogen and one of the pyridine nitrogen atoms are coordinated to the central iridium atom forming a five membered metallocycle, whereas in the minor isomer both the pyridine nitrogen atoms are coordinated to the iridium atom forming a six membered metallacyclic ring. Di‐2‐pyridyl ketoxime react with [(arene)MCl2]2 to form complexes bearing formula [(p‐cymene)Ru{pyC(py)NOH}Cl]PF6 ( 2 ); [(benzene)Ru{pyC(py)NOH}Cl]PF6 ( 3 ), and [Cp*Rh{pyC(py)NOH}Cl]PF6 ( 4 ). In case of complex 3 the ligand coordinates to the metal by using oxime nitrogen and one of the pyridine nitrogen atoms, whereas in complex 4 both the pyridine nitrogen atoms are coordinated to the metal ion. The complexes were fully characterized by spectroscopic techniques. 相似文献
15.
Bio‐Inspired Transition Metal–Organic Hydride Conjugates for Catalysis of Transfer Hydrogenation: Experiment and Theory
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Alex McSkimming Dr. Bun Chan Dr. Mohan M. Bhadbhade Dr. Graham E. Ball Prof. Stephen B. Colbran 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2821-2834
Taking inspiration from yeast alcohol dehydrogenase (yADH), a benzimidazolium (BI+) organic hydride‐acceptor domain has been coupled with a 1,10‐phenanthroline (phen) metal‐binding domain to afford a novel multifunctional ligand ( L BI+) with hydride‐carrier capacity ( L BI++H?? L BIH). Complexes of the type [Cp*M( L BI)Cl][PF6]2 (M=Rh, Ir) have been made and fully characterised by cyclic voltammetry, UV/Vis spectroelectrochemistry, and, for the IrIII congener, X‐ray crystallography. [Cp*Rh( L BI)Cl][PF6]2 catalyses the transfer hydrogenation of imines by formate ion in very goods yield under conditions where the corresponding [Cp*Ir( L BI)Cl][PF6] and [Cp*M(phen)Cl][PF6] (M=Rh, Ir) complexes are almost inert as catalysts. Possible alternatives for the catalysis pathway are canvassed, and the free energies of intermediates and transition states determined by DFT calculations. The DFT study supports a mechanism involving formate‐driven Rh?H formation (90 kJ mol?1 free‐energy barrier), transfer of hydride between the Rh and BI+ centres to generate a tethered benzimidazoline (BIH) hydride donor, binding of imine substrate at Rh, back‐transfer of hydride from the BIH organic hydride donor to the Rh‐activated imine substrate (89 kJ mol?1 barrier), and exergonic protonation of the metal‐bound amide by formic acid with release of amine product to close the catalytic cycle. Parallels with the mechanism of biological hydride transfer in yADH are discussed. 相似文献
16.
The reaction of [{Ir(cod)(μ‐Cl)}2] and K2CO3 or of [{Ir(cod)(μ‐OMe)}2] alone with the non‐natural tetrapyrrole 2,2′‐bidipyrrin (H2BDP) yields, depending on the stoichiometry, the mononuclear complex [Ir(cod)(HBDP)] or the homodinuclear complex [{Ir(cod)}2(BDP)]. Both complexes react readily with carbon monoxide to yield the species [Ir(CO)2(HBDP)] and [{Ir(CO)2}2(BDP)], respectively. The results from NMR spectroscopy and X‐ray diffraction reveal different conformations for the tetrapyrrolic ligand in both complexes. The reaction of [{Ir(coe)2(μ‐Cl)}2] with H2BDP proceeds differently and yields the macrocyclic [4e?,2H+]‐oxidized product [IrCl2(9‐Meic)] (9‐Meic = monoanion of 9‐methyl‐9,10‐isocorrole), which can be addressed as an iridium analog of cobalamin. 相似文献
17.
Ayhan Elmali Ebru Kavlakoglu YalcÛn Elerman Ingrid Svoboda 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1097-1099
The title compound, aquachloro{4,4′‐dibromo‐2,2′‐[o‐phenylenebis(nitrilomethylidyne)]diphenolato‐O,N,N′,O′}iron(III)–chloro{4,4′‐dibromo‐2,2′‐[o‐phenylenebis(nitrilomethyli‐dyne)]diphenolato‐O,N,N′,O′}iron(III)–dimethylformamide (1/1/1), [FeCl(C20H12Br2N2O2)][FeCl(C20H12Br2N2O2)(H2O)]·C3H7NO, contains one independent five‐coordinate [FeCl(C20H12Br2N2O2)] monomer, one six‐coordinate [FeCl(C20H12Br2N2O2)(H2O)] monomer and a non‐coordinating dimethylformamide solvent molecule in the asymmetric unit. In the five‐coordinate monomer, the Fe atom shows distorted square‐pyramidal geometry, with the N and O atoms of the ligand at the base and the Cl atom at the apex of the pyramid. In the six‐coordinate monomer, the Fe atom is in a distorted octahedral geometry and coordinated by the donor atoms of the tetrafunctional ligand in the horizontal plane, and the coordination sphere is completed by the O atom of the water molecule and the Cl atom at the axial positions. The title compound contains intermolecular O—H?O hydrogen bonds. Apart from these hydrogen bonds, there are also intermolecular C—H?Cl and C—H?O contacts. 相似文献
18.
Evgen V. Govor Andrey B. Lysenko Konstantin V. Domasevitch 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(5):m201-m204
New coordination compounds with the 4,4′‐bi‐1,2,4‐triazole ligand (btr), namely tetraaqua‐2κ4O‐di‐μ2‐4,4′‐bi‐1,2,4‐triazole‐1:2κ2N1:N1′;2:3κ2N1:N1′‐hexachlorido‐1κ3Cl,3κ3Cl‐trizinc(II), [Zn3Cl6(C4H4N6)2(H2O)4], (I), and poly[cadmium(II)‐μ2‐4,4′‐bi‐1,2,4‐triazole‐κ2N1:N2‐di‐μ2‐chlorido], [CdCl2(C4H4N6)]n, (II), reveal an unprecedented molecular zwitterionic structure for (I) and a polymeric two‐dimensional layer structure for (II). Differences between these products, which involve the formation of either charge‐separated chlorometallate/aquametal fragments or complementary organic and inorganic bridges, are attributable to the hardness–softness characters of the metal cations. In (I), two N1,N1′‐bidentate btr molecules connect one [Zn(H2O)4]2+ cation and two [ZnCl3]− anions into a linear trizinc motif (the Zn atom of the cation occupies a centre of inversion in an N2O4 coordination octahedron, whereas the Zn atom of the anion possesses a distorted tetrahedral Cl3N environment). In (II), the distorted vertex‐sharing CdCl4N2 octahedra are linked into binuclear [Cd2(μ2‐Cl)(μ2‐btr)2]3+ fragments by unprecedented N1:N2‐bidentate btr double bridges and bridging chloride ligands, while the additional chloride anions are also bridging, providing further propagation of the fragments into a two‐dimensional network [Cd—Cl = 2.5869 (2)–2.6248 (7) Å]. 相似文献
19.
Hai‐Jing Nie Xialing Chen Chang‐Jiang Yao Prof. Dr. Yu‐Wu Zhong Prof. Dr. Geoffrey R. Hutchison Prof. Dr. Jiannian Yao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(45):14497-14509
Electron delocalization of new mixed‐valent (MV) systems with the aid of lateral metal chelation is reported. 2,2′‐Bipyridine (bpy) derivatives with one or two appended di‐p‐anisylamino groups on the 5,5′‐positions and a coordinated [Ru(bpy)2] (bpy=2,2′‐bipyridine), [Re(CO)3Cl], or [Ir(ppy)2] (ppy=2‐phenylpyridine) component were prepared. The single‐crystal molecular structure of the bis‐amine ligand without metal chelation is presented. The electronic properties of these complexes were studied and compared by electrochemical and spectroscopic techniques and DFT/TDDFT calculations. Compounds with two di‐p‐anisylamino groups were oxidized by a chemical or electrochemical method and monitored by near‐infrared (NIR) absorption spectral changes. Marcus–Hush analysis of the resulting intervalence charge‐transfer transitions indicated that electron coupling of these mixed‐valent systems is enhanced by metal chelation and that the iridium complex has the largest coupling. TDDFT calculations were employed to interpret the NIR transitions of these MV systems. 相似文献
20.
Dr. Alexey V. Polukeev 《欧洲无机化学杂志》2023,26(31):e202300351
Synthesis, characterization and catalytic activity of cyclometalated iridium complexes with a bidentate POC ligand is presented. Metalation of POC-H (di-tert-butyl(phenoxy)phosphane) with [Ir(COD)Cl]2 proceeded rapidly at room temperature and afforded mixture of (POC)(POC-H)IrHCl ( 1 a ) and (POC)(COD)IrHCl ( 1 b ), from which complexes (POC)(L)IrHCl where L=PPh3 ( 1 c ), bipyridine ( 1 d ) and [2,2′-bipyridine]-6,6′-diol ( 1 e ) were prepared through ligand exchange. The compounds were tested in acceptorless dehydrogenation of 1-phenylethanol and transfer dehydrogenation of ethanol in a context of comparison with pincer counterparts (POCOP)IrHCl and (PCN)IrHCl. An attempt to prepare a dihydride complex from 1 e led to dimeric complex [(POC)(bipy-diol−)IrH]2 ( 3 ) that could explain the low activity of 1 e . DFT studies provided insight into POC-H vs POCOP-H metalation mechanism. 相似文献