Construction of [(eta5-C5Me5)MoS3Cu3]-based supramolecular assemblies from the [(eta5-C5Me5)MoS3(CuNCS)3]- cluster anion and multitopic ligands with different symmetries

The assembly of a new family of [(eta5-C5Me5)MoS3Cu3]-supported supramolecular compounds from a preformed cluster [PPh4][(eta5-C5Me5)MoS3(CuNCS)3].DMF (1.DMF) with four multitopic ligands with different symmetries is described. Reactions of 1 with 1,2-bis(4-pyridyl)ethane (bpe) (Cs symmetry) or 1,4-pyrazine (1,4-pyz) (D2h symmetry) in aniline gave rise to two polymeric clusters {[{(eta5-C5Me5)MoS3Cu3}2(NCS)3(mu-NCS)(bpe)3].3aniline}n (2) and [(eta5-C5Me5)MoS3Cu3(1,4-pyz)(mu-NCS)2]n (3). On the other hand, solid-state reactions of 1 with 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpt) (D3h symmetry) or 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin (H2tpyp) (D4h symmetry if 21H and 23H of the H2tpyp are omitted) at 100 degrees C for 12 h followed by extraction with aniline yielded another two polymeric clusters {[(eta5-C5Me5)MoS3Cu3(tpt)(aniline)(NCS)2].0.75aniline. 0.5H2O}n (4) and {[(eta5-C5Me5)MoS3Cu3(NCS)(mu-NCS)(H2tpyp)0.4(Cu-tpyp)0.1].2aniline.2.5benzene}n (5). These compounds were characterized by elemental analysis, IR spectra, UV-vis spectra, 1H NMR, and X-ray analysis. Compound 2 consists of a 2D (6,3) network in which [(eta5-C5Me5)MoS3Cu3] cores serve both a T-shaped three-connecting node and an angular two-connecting node to interconnect other equivalent units through single bpe bridges, double bpe bridges, and mu-NCS bridges. Compound 3 has a 3D diamondlike framework in which each [(eta5-C5Me5)MoS3Cu3] core, acting as a tetrahedral connecting node, links four other neighboring units by 1,4-pyz bridges and mu-NCS bridges. Compound 4 contains a honeycomb 2D (6,3)core(6,3)tpt network in which each cluster core, serving a trigonal-planar three-connecting node, links three pairs of equivalent cluster cores via three tpt lignads. Compound 5 has a rare scalelike 2D (4,62)core(42,62)ligand network in which each cluster core acts as a T-shaped three-connecting node to link with other equivalent ones through mu-NCS bridges and H2tpyp (or Cu-tpyp) ligands. The results showed that the formation of the four different multidimensional topological structures was evidently affected by the symmetry of the ligands used. In addition, the third-order nonlinear optical properties of 1-5 in aniline were also investigated by using Z-scan techniques at 532 nm.     

Construction of [(eta5-C5Me5)WS3Cu3]-based supramolecular compounds from preformed incomplete cubane-like clusters [PPh4][(eta5-C5Me5)WS3(CuX)3] (X = CN, Br)

Approaches to the assembly of (eta5-C5Me5)WS3Cu3-based supramolecular compounds from two preformed incomplete cubane-like clusters [PPh4][(eta5-C5Me5)WS3(CuX)3] (X = CN, 1a; X = Br, 1b) have been investigated. Treatment of 1a with LiBr/1,4-pyrazine (1,4-pyz), pyridine (py), LiCl/py, or 4,4'-bipyridine (4,4'-bipy) and treatment of 1b with 4,4'-bipy gave rise to a new set of W/Cu/S cluster-based compounds, [Li[((eta5-C5Me5)WS3Cu3(mu3-Br))2(mu-CN)3].C6H6]infinity (2), [(eta5-C5Me5)WS3Cu3(mu-CN)2(py)]infinity (3), [[PPh4][(eta5-C5Me5)WS3Cu3(mu3-Cl)(mu-CN)(CN)].py]infinity (4), [PPh4]2[(eta5-C5Me5)WS3Cu3(CN)2]2(mu-CN)2.(4,4'-bipy) (5), and [[(eta5-C5Me5)WS3Cu3Br(mu-Br)(4,4'-bipy)].Et2O]infinity (6). The structures of 2-6 have been characterized by elemental analysis, IR spectra, and single-crystal X-ray crystallography. Compound 2 displays a 1D ladder-shaped chain structure built of square-like [[(eta5-C5Me5)WS3Cu3(mu3-Br)(mu-CN)]4](mu-CN)2(2-) anions via two pairs of Cu-mu-CN-Cu bridges. Compound 3 consists of a single 3D diamond-like network in which each (eta5-C5Me5)WS3Cu3 unit, serving as a tetrahedral node, interconnects with four other nearby units through Cu-mu-CN-Cu bridges. Compound 4 contains a 1D zigzag chain array made of cubane-like [(eta5-C5Me5)WS3Cu3(mu3-Cl)(mu-CN)(CN)]- anions linked by a couple of Cu-mu-CN-Cu bridges. Compound 5 contains a dimeric structure in which the two incomplete cubane-like [(eta5-C5Me5)WS3(CuCN)2(mu-CN)]- anions are strongly held together via a pair of Cu-mu-CN-Cu bridges. Compound 6 contains a 2D brick-wall layer structure in which dimers of [(eta5-C5Me5)WS3Cu3Br(4,4'-bipy)]2 are interconnected via four Cu-mu-Br-Cu bridges. The successful construction of (eta5-C5Me5)WS3Cu3-based supramolecular compounds 2-6 from the geometry-fixed clusters 1a and 1b may expand the scope of the rational design and construction of cluster-based supramolecular assemblies.     

Electron paramagnetic resonance and spectroscopic characteristics of electrogenerated mixed-valent systems [(eta 5-C5Me5)M(mu-L)M(eta 5-C5Me5)]+ (M = Rh, Ir; L = 2,5-diiminopyrazines) in relation to the radicals [(eta 5-C5Me5)ClM(mu-L)MCl(eta 5-C5Me5)]+ and [(eta 5-C5Me5)M(mu-L)MCl(eta 5-C5Me5)]2+

Electrochemical reduction of the dinuclear [(eta 5-C5Me5)ClM(mu-L)MCl(eta 5-C5Me5)]2+ ions (M = Rh, Ir; L = 2,5-bis(1-phenyliminoethyl)pyrazine (bpip) and 2,5-bis[1-(2,6-dimethylphenyl)iminoethyl]pyrazine (bxip)) proceeds via the paramagnetic intermediates [(eta 5-C5Me5)ClM(mu-L)MCl(eta 5-C5Me5)]+ (L = bpip) or [(eta 5-C5Me5)M(mu-L)MCl(eta 5-C5Me5)]2+ (L = bxip) and [(eta 5-C5Me5)M(mu-L)M(eta 5-C5Me5)]+. Whereas the first is clearly a radical species with a small g anisotropy, the chloride-free cations are distinguished by structured intervalence charge transfer (IVCT) bands in the near-infrared region and by rhombic electron paramagnetic resonance features between g = 1.9 and g = 2.3, which suggests considerable metal participation at the singly occupied MO. Alternatives for the d configuration assignment and for the role of the bisbidentate-conjugated bridging ligands will be discussed. The main difference between bpip and bxip systems is the destabilization of the chloride-containing forms through the bxip ligand for reasons of steric interference.     

IR and Raman characterization of the zincocenes (eta(5)-C5Me5)2Zn2 and (eta(5)-C5Me5)(eta(1)-C5Me5)Zn

The measured Raman and IR spectra of solid, polycrystalline bis(pentamethylcyclopentadienyl)dizinc, (eta(5)-C5Me5)2Zn2, 1, and bis(pentamethylcyclopentadienyl)monozinc, (eta(5)-C5Me5)(eta(1)-C5Me5)Zn, 8, are reported in some detail. The IR spectra of the vapors of 1 and 8 each trapped in a solid Ar matrix at 12 K confirm the essentially molecular character of the solids. The experimental results have been interpreted with particular reference (i) to the corresponding spectra of (68)Zn-enriched samples of the compounds, and (ii) to the spectra simulated by density functional theory (DFT) calculations at the B3LYP level. The marked differences of structure of 1 and 8 contrast with the relatively close similarity of their vibrational spectra, disparities being revealed only on detailed scrutiny, including the effects of (68)Zn enrichment, and primarily at wavenumbers below 1000 cm(-1). The Zn-Zn stretching motion of 1 features not as a single, well-defined mode identifiable with intense Raman scattering but in several normal modes which respond in varying degrees to (68)Zn substitution. A stretching force constant of 1.42 mdyne A(-1) has been estimated for the Zn-Zn bond of 1.     

Synthesis and structural characterization of Be(eta 5-C5Me5)(eta 1-C5Me4H). Evidence for ring-inversion leading to Be(eta 5-C5Me4H)(eta 1-C5Me5)

The mixed-ring beryllocene Be(C5Me5)(C5Me4H), that contains eta 5-C5Me5 and eta 1-C5Me4H rings, the latter bonded to the metal through the CH carbon atom (X-ray crystal structure) reacts at room temperature with CNXyl (Xyl = C6H3-2,6-Me2) to give an iminoacyl product, Be(eta 5-C5Me4H)[C(NXyl)C5Me5] derived from the inverted beryllocene structure Be (eta 5-C5Me4H)(eta 1-C5Me5).     

On the origin of dinitrogen hydrogenation promoted by [(eta5-C5Me4H)2Zr]2(mu2,eta2,eta2-N2)

The origin of the hydrogenation of the dinitrogen ligand in [(eta5-C5Me4H)2Zr]2(mu2,eta2,eta2-N2) has been investigated by a combined computational and experimental study. Density functional theory calculations on the zirconocene dinitrogen complex demonstrate significant imido character in the zirconium nitrogen bonds, arising from effective pi-back-bonding from the low-valent zirconium and the side-on bound N2 ligand. The twisted ground-state structure of the N2 complex is a key requirement for nitrogen hydrogenation, as calculations on the model complex [(eta5-C5H5)2Zr]2(mu2,eta2,eta2-N2) reveal reduced overlap as the dihedral angle between the zirconocene wedges approaches 0 degrees . Experimentally, isotopic labeling studies on the microscopic reverse are consistent with a 1,2-addition mechanism for nitrogen hydrogenation.     

A photoswitchable molecular wire with the dithienylethene (DTE) linker, (dppe)(eta(5)-C(5)Me(5))Fe-C[triple bond, length as m-dash]C-DTE-C[triple bond, length as m-dash]C-Fe(eta(5)-C(5)Me(5))(dppe)

A redox-active diiron complex with the diethynylated dithienylethene (DTE) linker, (dppe)(eta(5)-C(5)Me(5))Fe-C[triple bond, length as m-dash]C-DTE-C[triple bond, length as m-dash]C-Fe(eta(5)-C(5)Me(5))(dppe), shows photochromic behaviour, which switches on and off the communication performance between the two metal centres.     

[(η5-C5Me5)WS3Cu3Br2(PPyPh2)2]四核簇合物的合成和晶体结构

以2[(η5-C5Me5)WS3(CuBr)3]2和diphenyl-2-pyridylphosphine (PPyPh2)在乙腈中反应得到标题化合物[(η5-C5Me5)WS3Cu3Br2(PPyPh2)2], 对该产物进行了元素分析、 IR、 UV-Vis和1H NMR 谱表征, 并测定了晶体结构. 该化合物晶体属三斜晶系, P1空间群, 晶胞参数: a=1.545 9(7) nm, b=1.62 0(1) nm, c=1.018 0(2) nm, α=94.18(3)°, β=97.38(3)°, γ=111.81(4)°, V=2.327(2) nm3, Z=2, Dc=1.84 g*cm-3, F(000)=1 260, μ=57.77 cm-1, 最终偏离因子R=0.029. 此簇合物结构可视为由一个[(η5-C5Me5)WS3]单元和3个Cu组成的开口立方烷, 其中2个Cu是畸变四面体配位, 第3个Cu是近似三角平面配位. W-Cu(1), W-Cu(2) 和W-Cu(3)距离分别为0.270 41(9), 0.273 27(8), 0.267 85(9) nm.     

Zinc-zinc bonded zincocene structures. Synthesis and characterization of Zn2(eta5-C5Me5)2 and Zn2(eta5-C5Me4Et)2

While, in general, decamethylzincocene, Zn(C5Me5)2, and other zincocenes, Zn(C5Me4R)2 (R = H, But, SiMe3), react with dialkyl and diaryl derivatives, ZnR'2, to give the half-sandwich compounds (eta5-C5Me4R)ZnR', under certain conditions the reactions of Zn(C5Me5)2 with ZnEt2 or ZnPh2 produce unexpectedly the dizincocene Zn2(eta5-C5Me5)2 (1) in low yields, most likely as a result of the coupling of two (eta5-C5Me5)Zn* radicals. An improved, large scale (ca. 2 g) synthesis of 1 has been achieved by reduction of equimolar mixtures of Zn(C5Me5)2 and ZnCl2 with KH in tetrahydrofuran. The analogous reduction of Zn(C5Me4R)2 (R = H, SiMe3, But) yields only decomposition products, but the isotopically labeled dimetallocene 68Zn2(eta5-C5Me5)2 and the related compound Zn2(eta5-C5Me4Et)2 (2) have been obtained by this procedure. Compound 2 has lower thermal stability than 1, but it has been unequivocally characterized by low-temperature X-ray diffraction studies. As for 1 a combination of structural characterization techniques has provided unambiguous evidence for its formulation as the Zn-Zn bonded dimer Zn2(eta5-C5Me4Et)2, with a short Zn-Zn bond of 2.295(3) A indicative of a strong Zn-Zn bonding interaction. The electronic structure and the bonding properties of 1 and those of related dizincocenes Zn2(eta5-Cp')2 have been studied by DFT methods (B3LYP level), with computed bond distances and angles for dizincocene 1 very similar to the experimental values. The Zn-Zn bond is strong (ca. 62 kcal.mol-1 for 1) and resides in the HOMO-4, that has a contribution of Zn orbitals close to 60%, consisting mostly of the Zn 4s orbitals (more than 96%).     

Reductive reactivity of the organolanthanide hydrides, [(C5Me5)2LnH]x, leads to ansa-allyl cyclopentadienyl (eta(5)-C5Me4CH2-C5Me4CH2-eta(3))2- and trianionic cyclooctatetraenyl (C8H7)3- ligands

The reductive reactivity of lanthanide hydride ligands in the [(C5Me5)2LnH]x complexes (Ln = Sm, La, Y) was examined to see if these hydride ligands would react like the actinide hydrides in [(C5Me5)2AnH2]2 (An = U, Th) and [(C5Me5)2UH]2. Each lanthanide hydride complex reduces PhSSPh to make [(C5Me5)2Ln(mu-SPh)]2 in approximately 90% yield. [(C5Me5)2SmH]2 reduces phenazine and anthracene to make [(C5Me5)2Sm]2(mu-eta(3):eta(3)-C12H8N2) and [(C5Me5)2Sm]2(mu-eta(3):eta(3)-C10H14), respectively, but the analogous [(C5Me5)2LaH]x and [(C5Me5)2YH]2 reactions are more complicated. All three lanthanide hydrides reduce C8H8 to make (C5Me5)Ln(C8H8) and (C5Me5)3Ln, a reaction that constitutes another synthetic route to (C5Me5)3Ln complexes. In the reaction of [(C5Me5)2YH]2 with C8H8, two unusual byproducts are obtained. In benzene, a (C5Me5)Y[(eta(5)-C5Me4CH2-C5Me4CH2-eta(3))] complex forms in which two (C5Me5)(1-) rings are linked to make a new type of ansa-allyl-cyclopentadienyl dianion that binds as a pentahapto-trihapto chelate. In cyclohexane, a (C5Me5)2Y(mu-eta(8):eta(1)-C8H7)Y(C5Me5) complex forms in which a (C8H8)(2-) ring is metalated to form a bridging (C8H7)(3-) trianion.     

Macropolyhedral boron-containing cluster chemistry. Ligand-induced two-electron variations of intercluster bonding intimacy. Structures of nineteen-vertex [(eta5-C5Me5)HIrB18H19(PMe2Ph)] and the related carbene complex [(eta5-C5Me5)HIrB18H19[C(NHMe)2]

Addition of PMe2Ph to fused-cluster syn-[(eta5-C5Me5)IrB18H20] 1 to give [(eta5-C5Me5)HIrB18H19(PMe2Ph)] 3 entails a diminution in the degree of intimacy of the intercluster fusion, rather than retention of inter-subcluster binding intimacy and a nido-->arachno conversion of the character of either of the subclusters. Reaction with MeNC gives [(eta5-C5Me5)HIrB18H19[C(NHMe)2]] 4 which has a similar structure, but with the ligand now being the carbene [:C(NHMe)2], resulting from a reductive assembly reaction involving two MeNC residues and the loss of a carbon atom.     

Condensed metallaborane clusters: synthesis and structure of Fe2(CO)6(eta5-C5Me5RuCO)(eta5-C5Me5Ru)B6H10

Mild pyrolysis of (eta5-C5Me5Ru)2B6H12 with Fe2(CO)9 yields the 12 skeletal electron pair (sep) Fe2(CO)6(eta5-C5Me5RuCO)(eta5-C5Me5Ru)B6H10 cluster; the title compound represents a novel class of hybrid multiple cluster in which a Fe2B2 tetrahedron has been fused to a ruthenaborane substrate.