Trajectory of Approach of a Zinc–Hydrogen Bond to Transition Metals

Through a dramatic advance in the coordination chemistry of the zinc–hydride bond, we describe the trajectory for the approach of this bond to transition metals. The dynamic reaction coordinate was interrogated through analysis of a series of solid state structures and is one in which the TM‐H‐Zn angle becomes increasingly acute as the TM–Zn distance decreases. Parallels may be drawn with the oxidative addition of boron–hydrogen and silicon–hydrogen bonds to transition metal centers.     

Syntheses,Structures and Luminescent Properties of Metal Halide Complexes Containing 2,3‐Diphenylquinoxaline

The reaction of CuI with 2,3‐diphenylquinoxaline ( L ) in 1:1 mole proportion in CH₃CN/THF afforded the dinuclear complex [CuI( L )]₂, 1 , whereas the reactions of MX₂ (M = Cu; Hg) with L in 1:2 mole proportion in CH₃OH gave the mononuclear complexes CuX₂( L )₂ (X = Cl, 2 ; Br, 3 ) and HgX₂( L )₂ (X = Cl, 4 ; Br, 5 ). Formulations of all the complexes were determined on the basis of X‐ray crystallography, elemental, IR‐ and emission spectroscopy. X‐ray examination revealed that complex 1 forms the μ,μ‐iodobridged dimer with distorted trigonal planar geometry through coordination of L ligand by one nitrogen atom to the Cu(I) center. The metal centers of complexes 2 and 3 form distorted square planar geometry while those of complexes 4 and 5 form linear geometry. The molecules of these complexes are interlinked through C‐H—π and/or π‐π stacking and anion—π interactions that form the packed structure. All the complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π r? π* transitions.     

σ–π Continuum in Indole–Palladium(II) Complexes

The intrinsic features of (hetero‐arene)–metal interactions have been elusive mainly because the systematic structure analysis of non‐anchored hetero‐arene–metal complexes has been hampered by their labile nature. We report successful isolation and systematic structure analysis of a series of non‐anchored indole–palladium(II) complexes. It was revealed that there is a σ–π continuum for the indole–metal interaction, while it has been thought that the dominant coordination mode of indole to a metal center is the Wheland‐intermediate‐type σ‐mode in light of the seemingly strong electron‐donating ability of indole. Several factors which affect the σ‐ or π‐character of indole–metal interactions are discussed.     

烃基取代茚基钌羰基化合物的合成及晶体结构(英文)

配体C9H7R(R=CH2CH2CH3(1),CH(CH3)2(2),C5H9(3),CH2C6H5(4),CH2CH=CH2(5))分别与Ru3(CO)12在二甲苯或庚烷中加热回流,得到了6个双核配合物[(η5-C9H6R)Ru(CO)(μ-CO)]2(R=CH2CH2CH3(6),CH(CH3)2(7),C5H9(8),CH2C6H5(9),CH2CH=CH2(10))和[(η5-C9H6)(H3CH2C)CHCH(CH2CH3)(η5-C9H6)][Ru(CO)(μ-CO)]2(11)。通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,9,10和11的结构。     

烃基取代茚基钌羰基化合物的合成及晶体结构

配体C₉H₇R(R=CH₂CH₂CH₃ (1),CH₂(CH₃)₂ (2),C₅H₉ (3),CH₂C₆H₅ (4),CH₂CH=CH₂ (5))分别与Ru₃(CO)12在二甲苯或庚烷中加热回流,得到了6个双核配合物[(η⁵-C₉H₆R)Ru(CO)(μ-CO)]₂(R=CH₂CH₂CH₃ (6),CH₂(CH₃)₂ (7),C₅H₈ (8),CH₂C₆H₅ (9),CH₂CH=CH₂ (10))和[(η⁵-C₉H₆)(H₃CH₂C)CHCH(CH₂CH₃)(η⁵-C₉H₆)] [Ru(CO)(μ-CO)]₂ (11).通过元素分析、红外光谱、核磁共振氢谱对配合物的结构进行了表征,并用X-射线单晶衍射法测定了配合物6,9,10和11的结构.     

Syntheses and Crystal Structures of Cadmium Complexes with Thiophenedicarboxylate and Bipyridine‐like Ligands

Two new coordination polymers [Cd(tdc)(bpy)(H₂O)]_n ( 1 ) and [Cd(tdc)(phen)]_n ( 2 ) (H₂tdc = thiophene‐2,5‐dicarboxylic acid, bpy = 2,2′‐bipyridine and phen = 1,10‐phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X‐ray single‐crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) Å, V = 7044(6) ų, Z = 16; 2 in the monoclinic space group P2₁/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) Å, β = 105.01(1)°, V = 1548.8(2) ų, Z = 4. Both of them are double‐stranded chains and further assembled into three‐dimensional networks by π‐π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.     

New Routes to a Series of σ‐Borane/Borate Complexes of Molybdenum and Ruthenium

A series of agostic σ‐borane/borate complexes have been synthesized and structurally characterized from simple borane adducts. A room‐temperature reaction of [Cp*Mo(CO)₃Me], 1 with Li[BH₃(EPh)] (Cp*=pentamethylcyclopentadienyl, E=S, Se, Te) yielded hydroborate complexes [Cp*Mo(CO)₂(μ‐H)BH₂EPh] in good yields. With 2‐mercapto‐benzothiazole, an N,S‐carbene‐anchored σ‐borate complex [Cp*Mo(CO)₂BH₃(1‐benzothiazol‐2‐ylidene)] ( 5 ) was isolated. Further, a transmetalation of the B‐agostic ruthenium complex [Cp*Ru(μ‐H)BHL₂] ( 6 , L=C₇H₄NS₂) with [Mn₂(CO)₁₀] affords a new B‐agostic complex, [Mn(CO)₃(μ‐H)BHL₂] ( 7 ) with the same structural motif in which the central metal is replaced by an isolobal and isoelectronic [Mn(CO)₃] unit. Natural‐bond‐orbital analyses of 5–7 indicate significant delocalization of the electron density from the filled σ_B?H orbital to the vacant metal orbital.     

Synthesis and Study of Cationic,Two‐Coordinate Triphenylphosphine– Gold–π Complexes

Cationic, two‐coordinate triphenylphosphine–gold(I)–π complexes of the form [(PPh₃)Au(π ligand)]⁺ SbF₆^? (π ligand=4‐methylstyrene, 1? SbF₆), 2‐methyl‐2‐butene ( 3? SbF₆), 3‐hexyne ( 6? SbF₆), 1,3‐cyclohexadiene ( 7? SbF₆), 3‐methyl‐1,2‐butadiene ( 8? SbF₆), and 1,7‐diphenyl‐3,4‐heptadiene ( 10? SbF₆) were generated in situ from reaction of [(PPh₃)AuCl], AgSbF₆, and π ligand at ?78 °C and were characterized by low‐temperature, multinuclear NMR spectroscopy without isolation. The π ligands of these complexes were both weakly bound and kinetically labile and underwent facile intermolecular exchange with free ligand (ΔG^≠≈9 kcal mol^?1 in the case of 6? SbF₆) and competitive displacement by weak σ donors, such as trifluoromethane sulfonate. Triphenylphosphine–gold(I)–π complexes were thermally unstable and decomposed above ?20 °C to form the bis(triphenylphosphine) gold cation [(PPh₃)₂Au]⁺SbF₆^? ( 2? SbF₆).     

New Heterocyclic Organophosphorus–Sulfur–Nitrogen Compounds,Syntheses and Structures

The new compound C₁₀H₆P(S)[NSi(CH₃)₃]₂P(S) ( 3 ) which contains a P₂N₂ heterocycle has been prepared in low yield by partial thermal decomposition of 1-{[N,N′-bis(trimethylsilyl)acetamidinium]sulfido}-3-(trimethylsilylamino)-1 H,3 H,1 λ⁵,3 λ⁵-naphtho[1,8 a,8-cd][1,2,6]thiadiphosphinine-1,3-dithione [CH₃C{NHSi(CH₃)₃}₂]⁺[C₁₀H₆P(S)(NHSiMe₃)SP(S)₂]^– ( 2 ). Reaction of 2 with potassium hydroxide in acetonitrile gives the completely desilylated product [CH₃C(NH₂)₂]⁺[C₁₀H₆P(S)(NH₂)SP(S)₂]^– ( 4 ). The structures of the new compounds 3 and 4 were elucidated by FTIR and NMR spectroscopy methods and by X-ray structure analyses.     

Vectorial Electron Transfer in Donor–Photosensitizer–Acceptor Triads Based on Novel Bis‐tridentate Ruthenium Polypyridyl Complexes

The first examples of rodlike donor–photosensitizer–acceptor arrays based on bis‐2,6‐di(quinolin‐8‐yl)pyridine Ru^II complexes 1 a and 3 a for photoinduced electron transfer have been synthesized and investigated. The complexes are synthesized in a convergent manner and are isolated as linear, single isomers. Time‐resolved absorption spectroscopy reveals long‐lived, photoinduced charge‐separated states (τ_CSS ( 1 a )=140 ns, τ_CSS ( 3 a )=200 ns) formed by stepwise electron transfer. The overall yields of charge separation (≥50 % for complex 1 a and ≥95 % for complex 3 a ) are unprecedented for bis‐tridentate Ru^II polypyridyl complexes. This is attributed to the long‐lived excited state of the [Ru(dqp)₂]²⁺ complex combined with fast electron transfer from the donor moiety following the initial charge separation. The rodlike arrangement of donor and acceptor gives controlled, vectorial electron transfer, free from the complications of stereoisomeric diversity. Thus, such arrays provide an excellent system for the study of photoinduced electron transfer and, ultimately, the harvesting of solar energy.     

Interplay between H‐Bonding and Preorganization in the Evolution of Self‐Assembled Systems

Cooperative π–π interactions and H‐bonding are frequently exploited in supramolecular polymerization; however, close scrutiny of their mutual interplay has been largely unexplored. Herein, we compare the self‐assembly behavior of a series of C₂‐ and C₃‐symmetrical oligophenyleneethynylenes differing in their amide topology (N‐ or C‐centered). This subtle structural modification brings about drastic changes in their photophysical and supramolecular properties, highlighting the reciprocal impact of H‐bonding vs. preorganization on the evolution and final outcome of supramolecular systems.     

Isolation of a Three‐Coordinate Boron Cation with a Boron–Sulfur Double Bond

The reaction of the bulky bis(imidazolin‐2‐iminato) ligand precursor (1,2‐(L^MesNH)₂‐C₂H₄)[OTs]₂ ( 1 ²⁺ 2[OTs]^?; L^Mes=1,3‐dimesityl imidazolin‐2‐ylidene, OTs=p‐toluenesulfonate) with lithium borohydride yields the boronium dihydride cation (1,2‐(L^MesN)₂‐C₂H₄)BH₂[OTs] ( 2 ⁺ [OTs]^?)_. The boronium cation 2 ⁺ [OTs]^? reacts with elemental sulfur to give the thioxoborane salt (1,2‐(L^MesN)₂‐C₂H₄)BS[OTs] ( 3 ⁺ [OTs]^?). The hitherto unknown compounds 1 ²⁺ 2[OTs]^?, 2 ⁺ [OTs]^?, and 3 ⁺ [OTs]^? were fully characterized by spectroscopic methods and single‐crystal X‐ray diffraction. Moreover, DFT calculations were carried out to elucidate the bonding situation in 2 ⁺ and 3 ⁺. The theoretical, as well as crystallographic studies reveal that 3 ⁺ is the first example for a stable cationic complex of three‐coordinate boron that bears a B?S double bond.     

From Metallaborane to Borylene Complexes: Syntheses and Structures of Triply Bridged Ruthenium and Tantalum Borylene Complexes

Reaction of [1,2‐(Cp*RuH)₂B₃H₇] ( 1 ; Cp*=η⁵‐C₅Me₅) with [Mo(CO)₃(CH₃CN)₃] yielded arachno‐[(Cp*RuCO)₂B₂H₆] ( 2 ), which exhibits a butterfly structure, reminiscent of 7 sep B₄H₁₀. Compound 2 was found to be a very good precursor for the generation of bridged borylene species. Mild pyrolysis of 2 with [Fe₂(CO)₉] yielded a triply bridged heterotrinuclear borylene complex [(μ₃‐BH)(Cp*RuCO)₂(μ‐CO){Fe(CO)₃}] ( 3 ) and bis‐borylene complexes [{(μ₃‐BH)(Cp*Ru)(μ‐CO)}₂Fe₂(CO)₅] ( 4 ) and [{(μ₃‐BH)(Cp*Ru)Fe(CO)₃}₂(μ‐CO)] ( 5 ). In a similar fashion, pyrolysis of 2 with [Mn₂(CO)₁₀] permits the isolation of μ₃‐borylene complex [(μ₃‐BH)(Cp*RuCO)₂(μ‐H)(μ‐CO){Mn(CO)₃}] ( 6 ). Both compounds 3 and 6 have a trigonal‐pyramidal geometry with the μ₃‐BH ligand occupying the apical vertex, whereas 4 and 5 can be viewed as bicapped tetrahedra, with two μ₃‐borylene ligands occupying the capping position. The synthesis of tantalum borylene complex [(μ₃‐BH)(Cp*TaCO)₂(μ‐CO){Fe(CO)₃}] ( 7 ) was achieved by the reaction of [(Cp*Ta)₂B₄H₈(μ‐BH₄)] at ambient temperature with [Fe₂(CO)₉]. Compounds 2 – 7 have been isolated in modest yield as yellow to red crystalline solids. All the new compounds have been characterized in solution by mass spectrometry; IR spectroscopy; and ¹H, ¹¹B, and ¹³C NMR spectroscopy and the structural types were unequivocally established by crystallographic analysis of 2 – 6 .     

Substitution‐Pattern‐ and Counteranion‐Depending Ion‐Pairing Assemblies Based on Electron‐Deficient Porphyrin–AuIII Complexes

Porphyrin–Au^III complexes, which were partially or totally modified with C₆F₅ at the meso positions, were synthesized. The highly electron‐withdrawing substituents induced electron‐deficient states and Lewis acid properties. Single‐crystal X‐ray analysis of the ion pairs revealed ion‐pairing assemblies with characteristics dependent on the number and substitution pattern of the C₆F₅ units and the geometries of the anions.     

A Dimeric Magnesium(I) Compound as a Facile Two‐Center/Two‐Electron Reductant

The odd couple : A dimeric magnesium(I) complex acts as a facile and selective two‐center/two‐electron reductant towards a series of unsaturated substrates (see scheme; Ar=2,6‐iPr₂C₆H₃, Ad=1‐adamantyl). The novel reduced or reductively coupled products obtained from these reductions suggest that magnesium(I) compounds may find wide use in organic and organometallic syntheses.

     

Driving Helical Packing of a Cyanine Dye on Dendron Nanofiber: Gel‐Shrinkage‐Triggered Chiral H‐Aggregation and Enhanced Enantiodiscrimination

An intelligent molecular hydrogel with a volume phase transition was constructed to regulate the chiral packing of a well‐known cyanine dye on a dynamically self‐assembled chiral nanofiber by using a pH trigger. During the shrinkage of the gel, the chiral nanofiber hierarchically assembled into a superhelix and simultaneously drove the dye molecules to stack, from a predominantly monomer form, in an unexpected helical H‐aggregation manner. Through such a transformation, the supramolecular chirality of the system was significantly enhanced and a new property of visual discrimination for chiral amines emerged.