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1.
Assembling two quadruply bonded dimolybdenum units [Mo2(DAniF)3]+ (DAniF=N,N′‐di(p‐anisyl)formamidinate) with 1,4‐naphthalenedicarboxylate and its thiolated derivatives produced three complexes [{Mo2(DAniF)3}2(μ‐1,4‐O2CC10H6CO2)], [{Mo2(DAniF)3}2(μ‐1,4‐OSCC10H6COS)], and [{Mo2(DAniF)3}2(μ‐1,4‐S2CC10H6CS2)]. In the X‐ray structures, the naphthalene bridge deviates from the plane defined by the two Mo?Mo bond vectors with the torsion angle increasing as the chelating atoms of the bridging ligand vary from O to S. The mixed‐valent species exhibit intervalence transition absorption bands with high energy and very low intensity. In comparison with the data for the phenylene analogues, the optically determined electronic coupling matrix elements (Hab=258–345 cm?1) are lowered by a factor of two or more, and the electron‐transfer rate constants (ket≈1011 s?1) are reduced by about one order of magnitude. These results show that, when the electron‐transporting ability of the bridge and electron‐donating (electron‐accepting) ability of the donor (acceptor) are both variable, the former plays a dominant role in controlling the intramolecular electron transfer. DFT calculations revealed that increasing the torsion angle enlarges the HOMO–LUMO energy gap by elevating the (bridging) ligand‐based LUMO energy. Therefore, our experimental results and theoretical analyses verify the superexchange mechanism for electronic coupling and electron transfer.  相似文献   

2.
Binding two quadruply bonded dimolybdenum units [Mo2(DAniF)3]+ (DAniF=N,N′‐di‐p‐anisylformamidinate) with two chalcogen atoms generated two molecules with a central core composed of a cyclic six‐membered [Mo2]2(μ‐EH)2 species (E=S in 1 and O in 3 , and [Mo2] is a quadruple‐bonded [Mo2(formamidinate)3] unit). Aerobic oxidation of 1 and 3 followed by concomitant deprotonation gave rise to the corresponding [Mo2]2(μ‐E)2 compounds 2 and 4 . The latter show a striking coplanarity and near‐bond equalization of the Mo/E cluster. The oxidized species 2 and 4 are diamagnetic in the measured temperature range of 5 to 300 K, which is somewhat unexpected for molecules that have dimetal units with a σ2π4δ1 electronic configuration. This suggests there are strong interactions between the dimolybdenum units through the E atoms. The large electronic delocalization of the δ electrons over the entire Mo/E core is supported by the exceptionally large potential separation for the two successive one‐electron reductions of the linked Mo25+ units from the oxidized species (ΔE1/2=1.7 V for the sulfur analogue). This large electronic delocalization has an important effect on the NMR spectroscopic signals for the two sets of methine (N‐(CH)‐N) protons from the DAniF ligands. Those essentially parallel to the core, H∥, and those essentially perpendicular to the core, H⊥, exhibit downfield and upfield chemical shifts, respectively, that are separated by δ=1.32 ppm. The structural, electronic, magnetic, and chemical behaviors for 2 and 4 are consistent with aromaticity, with the [Mo2E2Mo2] cores that resemble the prototypical benzene molecule. Theoretical studies, including DFT calculations, natural bond orbital (NBO) analyses, and gauge‐independent atomic orbital (GIAO) NMR spectroscopic calculations, are also consistent with the aromaticity of the [Mo2]2(μ‐E)2 units being promoted by dδ(Mo2)–pπ(E) π conjugation. The cyclic π conjugation of the central moiety in 2 and 4 involves a total of six electrons with 2e from δ(Mo2) and 4e from pπ(E) orbitals, thereby conforming to Hückel’s rule when electrons in the MOs with δ character are considered part of the delocalized system.  相似文献   

3.
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   

4.
Reaction of DyCl3 with two equivalents of NaN(SiMe3)2 in THF yielded {Dy(μ‐Cl)[N(SiMe3)2]2(THF)}2 ( 1 ). X‐ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln3+. Treatment of N,N‐bis(pyrrolyl‐α‐methyl)‐N‐methylamine (H2dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2, respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF)2]2 ( 2 ) and {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2 ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and 1H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl3 (Ln = Dy and Yb), LiN(SiMe3)2, and H2dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe3)2]2(THF)}2 are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma2– ligand.  相似文献   

5.
The two title compounds, [Mo2Ir2(C6H7)2(CO)10] and [Mo2Ir2(C9H13)2(CO)10]·0.5CH2Cl2, respectively, or collectively [Mo2Ir2(μ‐CO)3(CO)7(η5‐C5H5?nMen)2] (n = 1 or 4), have a pseudo‐tetrahedral Mo2Ir2 core geometry, an η5‐­C5H5?nMen group ligating each Mo atom, bridging carbonyls spanning the edges of an MoIr2 face and seven terminally bound carbonyl groups.  相似文献   

6.
N,N′‐dioxide ligands such as 2, 2′‐bipyridine‐N,N‐dioxide (BPDO‐I) and 4, 4′‐bipyridine‐N,N‐dioxide (BPDO‐II) were used to trap the hydrated dimethyltin cations under controlled hydrolysis. The use of the chelating ligand BPDO‐I leads to the isolation of the discrete monocation [Me2Sn(BPDO‐I)(OH2)(NO3)]+[NO3]– ( 2 ), whereas the linear ligand BPDO‐II directs the construction of cationic polymers, [{Me2Sn(OH2)2(μ‐BPDO‐II)}2+{NO3–}2 · 2H2O]n ( 3· 2H2O) and [{Me2Sn(μ‐OH)(BPDO‐II)}22+{NO3–}2 · H2O]n ( 4· H2O) under different reaction conditions.  相似文献   

7.
The quadruply bonded Mo24+ complex Mo2(DAniF)3(OOCC6F5) ( 1 ) [DAniF = N,N′‐bis(4‐methoxyphenyl)formamidinate] was synthesized. The solvate Mo2(DAniF)3(OOCC6F5) · (C6H6) ( 2 ) and co‐crystal Mo2(DAniF)3(OOCC6F5) · (C10H8) ( 3 ) complexes were obtained by self‐assembly of crystals of 1 with benzene and naphthalin, respectively. Compounds 1 , 2 , and 3 were structurally characterized by single‐crystal X‐ray diffraction. In monomer 1 , the Mo–Mo bond length of 2.0874(6) Å is typical for dimolybdenum quadruple bonds. The solvate complex 2 was stabilized by weak π–π stacking interactions between the benzene molecule and the pentafluorophenyl ring (as indicated by a center‐to‐center distance of 3.838(10) Å and a center‐to‐plane distance of 3.712(4) Å between phenyl and pentafluorophenyl ring) and intermolecular C–H ··· F–C interactions (the shortest F ··· H distance is 2.560(2) Å). In complex 3 , a one‐dimensional chain was formed by C–H ··· F–C interactions between the hydrogen atoms in naphthalin and the fluorine atoms in the monomer (H ··· F distances of 2.582(2) Å). Information on the structures in solution of the three crystals was obtained by 1H NMR spectroscopy.  相似文献   

8.
(Acetonitrile‐1κN)[μ‐1H‐benzimidazole‐2(3H)‐thione‐1:2κ2S:S][1H‐benzimidazole‐2(3H)‐thione‐2κS]bis(μ‐1,1‐dioxo‐1λ6,2‐benzothiazole‐3‐thiolato)‐1:2κ2S3:N;1:2κ2S3:S3‐dicopper(I)(Cu—Cu), [Cu2(C7H4NO2S2)2(C7H6N2S)2(CH3CN)] or [Cu2(tsac)2(Sbim)2(CH3CN)] [tsac is thiosaccharinate and Sbim is 1H‐benzimidazole‐2(3H)‐thione], (I), is a new copper(I) compound that consists of a triply bridged dinuclear Cu—Cu unit. In the complex molecule, two tsac anions and one neutral Sbim ligand bind the metals. One anion bridges via the endocyclic N and exocyclic S atoms (μ‐S:N). The other anion and one of the mercaptobenzimidazole molecules bridge the metals through their exocyclic S atoms (μ‐S:S). The second Sbim ligand coordinates in a monodentate fashion (κS) to one Cu atom, while an acetonitrile molecule coordinates to the other Cu atom. The CuI—CuI distance [2.6286 (6) Å] can be considered a strong `cuprophilic' interaction. In the case of [μ‐1H‐benzimidazole‐2(3H)‐thione‐1:2κ2S:S]bis[1H‐benzimidazole‐2(3H)‐thione]‐1κS;2κS‐bis(μ‐1,1‐dioxo‐1λ6,2‐benzothiazole‐3‐thiolato)‐1:2κ2S3:N;1:2κ2S3:S3‐dicopper(I)(Cu—Cu), [Cu2(C7H4NO2S2)2(C7H6N2S)3] or [Cu2(tsac)2(Sbim)3], (II), the acetonitrile molecule is substituted by an additional Sbim ligand, which binds one Cu atom via the exocylic S atom. In this case, the CuI—CuI distance is 2.6068 (11) Å.  相似文献   

9.
On the Reactivity of Alkylthio Bridged 44 CVE Triangular Platinum Clusters: Reactions with Bidentate Phosphine Ligands The 44 cve (cluster valence electrons) triangular platinum clusters [{Pt(PR3)}3(μ‐SMe)3]Cl (PR3 = PPh3, 2a ; P(4‐FC6H4)3, 2b ; P(n‐Bu)3, 2c ) were found to react with PPh2CH2PPh2 (dppm) in a degradation reaction yielding dinuclear platinum(I) complexes [{Pt(PR3)}2(μ‐SMe)(μ‐dppm)]Cl (PR3 = PPh3, 3a ; P(4‐FC6H4)3, 3b ; P(n‐Bu)3; 3e ) and the platinum(II) complex [Pt(SMe)2(dppm)] ( 4 ), whereas the addition of PPh2CH2CH2PPh2 (dppe) to cluster 2a afforded a mixture of degradation products, among others the complexes [Pt(dppe)2] and [Pt(dppe)2]Cl2. On the other hand, the treatment of cluster 2a with PPh2CH2CH2CH2PPh2 (dppp) ended up in the formation of the cationic complex [{Pt(dppp)}2(μ‐SMe)2]Cl2 ( 5 ). Furthermore, the terminal PPh3 ligands in complex 3a proved to be subject to substitution by the stronger donating monodentate phosphine ligands PMePh2 and PMe2Ph yielding the analogous complexes [{Pt(PR3)}2(μ‐SMe)(μ‐dppm)]Cl (PR3 = PMePh2, 3c ; PMe2Ph, 3d ). NMR investigations on complexes 3 showed an inverse correlation of Tolmans electronic parameter ν with the coupling constants 1J(Pt,P) and 1J(Pt,Pt). All compounds were fully characterized by means of NMR and IR spectroscopy. X‐ray diffraction analyses were performed for the complexes [{Pt{P(4‐FC6H4)3}}2(μ‐SMe)(μ‐dppm)]Cl ( 3b ), [Pt(SMe)2(dppm)] ( 4 ), and [{Pt(dppp)}2(μ‐SMe)2]Cl2 ( 5 ).  相似文献   

10.
Investigation of the Hydrolytic Build‐up of Iron(III)‐Oxo‐Aggregates The synthesis and structures of five new iron/hpdta complexes [{FeIII4(μ‐O)(μ‐OH)(hpdta)2(H2O)4}2FeII(H2O)4]·21H2O ( 2 ), (pipH2)2[Fe2(hpdta)2]·8H2O ( 4 ), (NH4)4[Fe6(μ‐O)(μ‐OH)5(hpdta)3]·20.5H2O ( 5 ), (pipH2)1.5[Fe4(μ‐O)(μ‐OH)3(hpdta)2]·6H2O ( 7 ), [{Fe6(μ3‐O)2(μ‐OH)2(hpdta)2(H4hpdta)2}2]·py·50H2O ( 9 ) are described and the formation of these is discussed in the context of other previously published hpdta‐complexes (H5hpdta = 2‐Hydroxypropane‐1, 3‐diamine‐N, N, N′, N′‐tetraacetic acid). Terminal water ligands are important for the successive build‐up of higher nuclearity oxy/hydroxy bridged aggregates as well as for the activation of substrates such as DMA and CO2. The formation of the compounds under hydrolytic conditions formally results from condensation reactions. The magnetic behaviour can be quantified analogously up to the hexanuclear aggregate 5 . The iron(III) atoms in 1 ‐ 7 are antiferromagnetically coupled giving rise to S = 0 spin ground states. In the dodecanuclear iron(III) aggregate 9 we observe the encapsulation of inorganic ionic fragments by dimeric{M2hpdta}‐units as we recently reported for AlIII/hpdta‐system.  相似文献   

11.
A novel mixed‐tribridged dimolybdenum(I) compound [Bn4N][Mo2(μ‐SPh)2(μ‐Cl)(CO)6] (1) has been synthesized from the reaction of Mo2(CO)3(SPh)2 with BU4NCl. Compound 1 was characterized by IR, UV‐Vis and 1H, 13C, 95Mo NMR spectroscopic analyses. The electrochemical behavior was measured by cyclic voltammetry, indicating a quasi‐reversible two‐electron transfer in one step. The crystal structure determined by X‐ray crystallography shows that 1 contains a [Mo2(μ‐S)2(μ‐Cl)]? core with a planar Mo2S2unit and a Cl bridge. The Mo? Mo distance is 0.28709(7) nm, and the Mo‐Cl‐Mo angle is 66.44(4)°. A newface‐sharing bioctahedral structure is discussed.  相似文献   

12.
By using cyclohexane‐1,2‐diamine (chxn), Ni(ClO4)2 ? 6H2O and Na3[Mo(CN)8] ? 4H2O, a 3D diamond‐like polymer {[NiII(chxn)2]2[MoIV(CN)8] ? 8H2O}n ( 1 ) was synthesised, whereas the reaction of chxn and Cu(ClO4)2 ? 6H2O with Na3[MV(CN)8] ? 4H2O (M=Mo, W) afforded two isomorphous graphite‐like complexes {[CuII(chxn)2]3[MoV(CN)8]2 ? 2H2O}n ( 2 ) and {[CuII(chxn)2]3[WV(CN)8]2 ? 2H2O}n ( 3 ). When the same synthetic procedure was employed, but replacing Na3[Mo(CN)8] ? 4H2O by (Bu3NH)3[Mo(CN)8] ? 4H2O (Bu3N=tributylamine), {[CuII(chxn)2MoIV(CN)8][CuII(chxn)2] ? 2H2O}n ( 4 ) was obtained. Single‐crystal X‐ray diffraction analyses showed that the framework of 4 is similar to 2 and 3 , except that a discrete [Cu(chxn)2]2+ moiety in 4 possesses large channels of parallel adjacent layers. The experimental results showed that in this system, the diamond‐ or graphite‐like framework was strongly influenced by the inducement of metal ions. The magnetic properties illustrate that the diamagnetic [MoIV(CN)8] bridges mediate very weak antiferromagnetic coupling between the NiII ions in 1 , but lead to the paramagnetic behaviour in 4 because [MoIV(CN)8] weakly coordinates to the CuII ions. The magnetic investigations of 2 and 3 indicate the presence of ferromagnetic coupling between the CuII and WV/MoV ions, and the more diffuse 5d orbitals lead to a stronger magnetic coupling interaction between the WV and CuII ions than between the MoV and CuII ions.  相似文献   

13.
The sodium salt of [immucillin‐A–CO2H]− (Imm‐A), namely catena‐poly[[[triaquadisodium(I)](μ‐aqua)[μ‐(1S)‐N‐carboxylato‐1‐(9‐deazaadenin‐9‐yl)‐1,4‐dideoxy‐1,4‐imino‐d ‐ribitol][triaquadisodium(I)][μ‐(1S)‐N‐carboxylato‐1‐(9‐deazaadenin‐9‐yl)‐1,4‐dideoxy‐1,4‐imino‐d ‐ribitol]] tetrahydrate], {[Na2(C12H13N4O6)2(H2O)7]·4H2O}n, (I), forms a polymeric chain via Na+—O interactions involving the carboxylate and keto O atoms of two independent Imm‐A molecules. Extensive N,O—H...O hydrogen bonding utilizing all water H atoms, including four waters of crystallization, provides crystal packing. The structural definition of this novel compound was made possible through the use of synchrotron radiation utilizing a minute fragment (volume ∼2.4 × 10−5 mm−3) on a beamline optimized for protein data collection. A summary of intra‐ring conformations for immucillin structures indicates considerable flexibility while retaining similar intra‐ring orientations.  相似文献   

14.
The reaction of a new heterocyclic bidentate N containing spacer, (ligand) 5,5′‐methylenebis(pyridine) with ruthenium sulphoxide precursors resulted, dinuclear complexes. We herein report three formulations; [{cis,fac‐RuCl2(so)3}2(μ‐mbp)].3so; [{trans,mer‐RuCl2(so)32}2(μ‐mbp)].3so and [{trans‐RuCl4(so)}2(μ‐mbp)]2?[X]2+; where so = dimethyl‐sulfoxide/tetramethylenesulfoxide; mbp = 5,5′‐methylenebis(pyridine) and [X]+ = [(dmso)2H]+, Na+ or [(tmso)H]+. These complexes were characterized on the basis of elemental analyses, molar conductance measurement, magnetic susceptibility, FT‐IR, 1H‐NMR, 13C{1H}‐NMR, electronic spectroscopy and FAB‐Mass spectrometry. Catalytic activity of these complexes has been investigated in hydrolysis of benzonitrile. All the complexes exhibit good antibacterial activity against gram‐negative bacteria Escherichia coli in comparison to Chloramphenicol.  相似文献   

15.
Three Ru(bpy)32+ derivatives tethered to multiple viologen acceptors, [Ru(bpy)2(4,4′‐MV2)]6+, [Ru(bpy)2(4,4′‐MV4)]10+, and [Ru(bpy)(4,4′‐MV4)2]18+ [bpy=2,2′‐bipyridine, 4,4′‐MV2=4‐ethoxycarbonyl‐4′‐(N‐G1‐carbamoyl)‐2,2′‐bipyridine, and 4,4′‐MV4=4,4′‐bis(N‐G1‐carbamoyl)‐2,2′‐bipyridine, where G1=Asp(NHG2)‐NHG2 and G2=‐(CH2)2‐N+C5H4‐C5H4N+‐CH3] were prepared as “photo‐charge separators (PCSs)”. Photoirradiation of these complexes in the presence of a sacrificial electron donor (EDTA) results in storage of electrons per PCS values of 1.3, 2.7, and 4.6, respectively. Their applications in the photochemical H2 evolution from water in the presence of a colloidal Pt H2‐evolving catalyst were investigated, and are discussed along with those reported for [Ru(bpy)2(5,5′‐MV4)]10+, [Ru(4,4′‐MV4)3]26+, and [Ru(5,5′‐MV4)3]26+ (Inorg. Chem. Front. 2016 , 3, 671–680). The PCSs with high dimerization constants (Kd=105–106 m ?1) are superior in driving H2 evolution at pH 5.0, whereas those with lower Kd values (103–104 m ?1) are superior at pH 7.0, where Kd=[(MV+)2]/[MV+ . ]2. The (MV+)2 site can drive H2 evolution only at pH 5.0 as a result of its 0.15 eV lower driving force for H2 evolution relative to MV+ . , whereas the PCSs with lower Kd values exhibit higher performance at pH 7.0 owing to the higher population of free MV+ . . Importantly, the rate of electron charging over the PCSs is linear to the apparent H2 evolution rate, and shows an intriguing quadratic dependence on the number of MV2+ units per PCS.  相似文献   

16.
An attempt has been made to design double‐stranded ladder‐like coordination polymers (CPs) of hemidirected PbII. Four CPs, [Pb(μ‐bpe)(O2C‐C6H5)2] ? 2H2O ( 1 ), [Pb2(μ‐bpe)2(μ‐O2C‐C6H5)2(O2C‐C6H5)2] ( 2 ), [Pb2(μ‐bpe)2(μ‐O2C‐p‐Tol)2(O2C‐p‐Tol)2] ? 1.5 H2O ( 3 ) and [Pb2(μ‐bpe)2(μ‐O2C‐m‐Tol)2(O2C‐m‐Tol)2] ( 4 ) (bpe=1,2‐bis(4′‐pyridyl)ethylene), have been synthesised and investigated for their solid‐state photoreactivity. CPs 2 – 4 , having a parallel orientation of bpe molecules in their ladder structures and being bridged by carboxylates, were found to be photoreactive, whereas CP 1 is a linear one‐dimensional (1D) CP with guest water molecules aggregating to form a hydrogen‐bonded 1D structure. The linear strands of 1 were found to pair up upon eliminating lattice water molecules by heating, which led to the solid‐state structural transformation of photostable linear 1D CP 1 into photoreactive ladder CP 2 . In the construction of the double‐stranded ladder‐like structures, the parallel alignment of C?C bonds in 2 – 4 is dictated by the chelating and μ2‐η2:η1 bridging modes of the benzoate and toluate ligands. The role of solvents in the formation of such double‐stranded ladder‐like structures has also been investigated. A single‐crystal‐to‐single‐crystal transformation occurred when 4 was irradiated under UV light to form [Pb2(rctt‐tpcb)(μ‐O2C‐m‐Tol)2(O2C‐m‐Tol)2] ( 5 ).  相似文献   

17.
The methylation of the uncoordinated nitrogen atom of the cyclometalated triruthenium cluster complexes [Ru3(μ‐H)(μ‐κ2N1,C6‐2‐Mepyr)(CO)10] ( 1 ; 2‐MepyrH=2‐methylpyrimidine) and [Ru3(μ‐H)(μ‐κ2N1,C6‐4‐Mepyr)(CO)10] ( 9 ; 4‐MepyrH=4‐methylpyrimidine) gives two similar cationic complexes, [Ru3(μ‐H)(μ‐κ2N1,C6‐2,3‐Me2pyr)(CO)10]+( 2 +) and [Ru3(μ‐H)(μ‐κ2N1,C6‐3,4‐Me2pyr)(CO)10]+ ( 9 +), respectively, whose heterocyclic ligands belong to a novel type of N‐heterocyclic carbenes (NHCs) that have the Ccarbene atom in 6‐position of a pyrimidine framework. The position of the C‐methyl group in the ligands of complexes 2 + (on C2) and 9 + (on C4) is of key importance for the outcome of their reactions with K[N(SiMe3)2], K‐selectride, and cobaltocene. Although these reagents react with 2 + to give [Ru3(μ‐H)(μ‐κ2N1,C6‐2‐CH2‐3‐Mepyr)(CO)10] ( 3 ; deprotonation of the C2‐Me group), [Ru3(μ‐H)(μ3‐κ3N1,C5,C6‐4‐H‐2,3‐Me2pyr)(CO)9] ( 4 ; hydride addition at C4), and [Ru6(μ‐H)2{μ6‐κ6N1,N1′,C5,C5′,C6,C6′‐4,4′‐bis(2,3‐Me2pyr)}(CO)18] ( 5 ; reductive dimerization at C4), respectively, similar reactions with 9 + have only allowed the isolation of [Ru3(μ‐H)(μ3‐κ2N1,C6‐2‐H‐3,4‐Me2pyr)(CO)9] ( 11 ; hydride addition at C2). Compounds 3 and 11 also contain novel six‐membered ring NHC ligands. Theoretical studies have established that the deprotonation of 2 + and 9 + (that have ligand‐based LUMOs) are charge‐controlled processes and that both the composition of the LUMOs of these cationic complexes and the steric protection of their ligand ring atoms govern the regioselectivity of their nucleophilic addition and reduction reactions.  相似文献   

18.
This article deals with the hitherto unexplored metal complexes of deprotonated 6,12‐di(pyridin‐2‐yl)‐5,11‐dihydroindolo[3,2‐b]carbazole (H2L). The synthesis and structural, optical, electrochemical characterization of dimeric [{RuIII(acac)2}2(μ‐L.?)]ClO4 ([ 1 ]ClO4, S=1/2), [{RuII(bpy)2}2(μ‐L.?)](ClO4)3 ([ 2 ](ClO4)3, S=1/2), [{RuII(pap)2}2(μ‐L2?)](ClO4)2 ([ 4 ](ClO4)2, S=0), and monomeric [(bpy)2RuII(HL?)]ClO4 ([ 3 ]ClO4, S=0), [(pap)2RuII(HL?)]ClO4 ([ 5 ]ClO4, S=0) (acac=σ‐donating acetylacetonate, bpy=moderately π‐accepting 2,2’‐bipyridine, pap=strongly π‐accepting 2‐phenylazopyridine) are reported. The radical and dianionic states of deprotonated L in isolated dimeric 1 +/ 2 3+ and 4 2+, respectively, could be attributed to the varying electronic features of the ancillary (acac, bpy, and pap) ligands, as was reflected in their redox potentials. Perturbation of the energy level of the deprotonated L or HL upon coordination with {Ru(acac)2}, {Ru(bpy)2}, or {Ru(pap)2} led to the smaller energy gap in the frontier molecular orbitals (FMO), resulting in bathochromically shifted NIR absorption bands (800–2000 nm) in the accessible redox states of the complexes, which varied to some extent as a function of the ancillary ligands. Spectroelectrochemical (UV/Vis/NIR, EPR) studies along with DFT/TD‐DFT calculations revealed (i) involvement of deprotonated L or HL in the oxidation processes owing to its redox non‐innocent potential and (ii) metal (RuIII/RuII) or bpy/pap dominated reduction processes in 1 + or 2 2+/ 3 +/ 4 2+/ 5 +, respectively.  相似文献   

19.
By using a linear tetraphosphine, meso‐bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm), nona‐ and hexadecanuclear copper hydride clusters, [Cu9H7(μ‐dpmppm)3]X2 (X=Cl ( 1 a ), Br ( 1 b ), I ( 1 c ), PF6 ( 1 d )) and [Cu16H14(μ‐dpmppm)4]X2 (X2=I2 ( 2 c ), (4/3) PF6?(2/3) OH ( 2 d )) were synthesized and characterized. They form copper‐hydride cages of apex‐truncated supertetrahedral {Cu9H7}2+ and square‐face‐capped cuboctahedral {Cu16H14}2+ structures. The hydride positions were estimated by DFT calculations to be facially dispersed around the copper frameworks. A kinetically controlled synthesis gave an unsymmetrical Cu8H6 cluster, [Cu8H6(μ‐dpmppm)3]2+ ( 3 ), which readily reacted with CO2 to afford linear Cu4 complexes with formate bridges, leading to an unprecedented hydrogenation of CO2 into formate catalyzed by {Cu4(μ‐dpmppm)2} platform. The results demonstrate that new motifs of copper hydride clusters could be established by the tetraphosphine ligands, and the structures influence their reactivity.  相似文献   

20.
The complex series [Ru(pap)(Q)2]n ([ 1 ]n–[ 4 ]n; n=+2, +1, 0, ?1, ?2) contains four redox non‐innocent entities: one ruthenium ion, 2‐phenylazopyridine (pap), and two o‐iminoquinone moieties, Q=3,5‐di‐tert‐butyl‐N‐aryl‐1,2‐benzoquinonemonoimine (aryl=C6H5 ( 1+ ); m‐(Cl)2C6H3 ( 2+ ); m‐(OCH3)2C6H3 ( 3+ ); m‐(tBu)2C6H3 ( 4 +)). A crystal structure determination of the representative compound, [ 1 ]ClO4, established the crystallization of the ctt‐isomeric form, that is, cis and trans with respect to the mutual orientations of O and N donors of two Q ligands, and the coordinating azo N atom trans to the O donor of Q. The sensitive C? O (average: 1.299(3) Å), C? N (average: 1.346(4) Å) and intra‐ring C? C (meta; average: 1.373(4) Å) bond lengths of the coordinated iminoquinone moieties in corroboration with the N?N length (1.292(3) Å) of pap in 1 + establish [RuIII(pap0)(Q.?)2]+ as the most appropriate electronic structural form. The coupling of three spins from one low‐spin ruthenium(III) (t2g5) and two Q.? radicals in 1 +– 4 + gives a ground state with one unpaired electron on Q.?, as evident from g=1.995 radical‐type EPR signals for 1 +– 4 +. Accordingly, the DFT‐calculated Mulliken spin densities of 1 + (1.152 for two Q, Ru: ?0.179, pap: 0.031) confirm Q‐based spin. Complex ions 1 +– 4 + exhibit two near‐IR absorption bands at about λ=2000 and 920 nm in addition to intense multiple transitions covering the visible to UV regions; compounds [ 1 ]ClO4–[ 4 ]ClO4 undergo one oxidation and three separate reduction processes within ±2.0 V versus SCE. The crystal structure of the neutral (one‐electron reduced) state ( 2 ) was determined to show metal‐based reduction and an EPR signal at g=1.996. The electronic transitions of the complexes 1 n– 4 n (n=+2, +1, 0, ?1, ?2) in the UV, visible, and NIR regions, as determined by using spectroelectrochemistry, have been analyzed by TD‐DFT calculations and reveal significant low‐energy absorbance (λmax>1000 nm) for cations, anions, and neutral forms. The experimental studies in combination with DFT calculations suggest the dominant valence configurations of 1 n– 4 n in the accessible redox states to be [RuIII(pap0)(Q.?)(Q0)]2+ ( 1 2+– 4 2+)→[RuIII(pap0)(Q.?)2]+ ( 1 +– 4 +)→[RuII(pap0)(Q.?)2] ( 1 – 4 )→[RuII(pap.?)(Q.?)2]? ( 1 ?– 4 ?)→[RuIII(pap.?)(Q2?)2]2? ( 1 2?– 4 2?).  相似文献   

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