Crystal structure of the two-dimensional coordination polymer poly[di-µ-bromido-bis-(µ-tetra-hydro-thiophene)-dicopper(I)].

The polymeric title compound, [Cu2Br2(C4H8S)2] n , CP1, represents an example of a two-dimensional coordination polymer resulting from reaction of CuBr with tetra-hydro-thio-phene (THT) in MeCN solution. The two-dimensional layers consist of two different types of rhomboid-shaped dinuclear Cu(µ2-Br)2Cu secondary building units (SBUs); one with a quite loose Cu⋯Cu separation of 3.3348 (10) Šand a second one with a much closer inter-metallic contact of 2.9044 (9) Å. These SBUs are inter-connected through bridging THT ligands, in which the S atom acts as a four-electron donor bridging each Cu(µ2-Br)2Cu unit in a µ2-bonding mode. In the crystal, the layers are linked by very weak C-H⋯·Br hydrogen bonds with H⋯Br distances of 2.95 Å, thus giving rise to a three-dimensional supra-molecular network.

2-Azabutadiene complexes of rhenium(I): S,N-chelated species with photophysical properties heavily governed by the ligand hidden traits.

The reaction of [Re(CO)3(THF)(µ-Br)]2 or [Re(CO)5X] (X = Cl, Br, I) with the diaryl-2-azabutadienes [(RS)2C[double bond, length as m-dash]C(H)-N[double bond, length as m-dash]CAr2] containing two thioether arms at the 4,4-position forms the luminescent S,N-chelate complexes fac-[(OC)3ReX{(RS)2C[double bond, length as m-dash]C(H)-N[double bond, length as m-dash]CAr2}] (1a-h). The halide abstraction by silver triflate converts [(OC)3ReCl{(PhS)2C[double bond, length as m-dash]C(H)-N[double bond, length as m-dash]CPh2}] (1c) to [(OC)3Re(OS([double bond, length as m-dash]O)2CF3){(PhS)2C[double bond, length as m-dash]C(H)-N[double bond, length as m-dash]CPh2}] (1j) bearing a covalently bound triflate ligand. The cyclic voltammograms reveal reversible S^N ligand-centred reduction and irreversible oxidation waves for all complexes. The crystal structures of nine octahedral complexes have been determined along with that of (NaphtylS)2C[double bond, length as m-dash]C(H)-N[double bond, length as m-dash]CPh2 (L6). A rich system of weak non-covalent intermolecular secondary interactions through CHX(Cl, Br)Re, CHO, COπ(Ph), CHπCO, CHO and CHS contacts has been evidenced. The photophysical properties have been investigated by steady-state and time-resolved absorption (fs transient absorption, fs-TAS) and emission (ns-TCSPC and ps-Streak camera) spectroscopy in 2-MeTHF solution at 298 and 77 K. The emission bands are composed of either singlet (450 < λmax < 535 nm) and/or triplet emissions (at 77 K only, λmax < 640 nm, or appearing as a tail at λ > 600 nm), which decay in a multiexponential manner for the fluorescence (short ps (i.e.

Crystal structure of 4,4-di-bromo-1-(3,4-di-meth-oxy-phen-yl)-2-aza-buta-1,3-diene-1-carbo-nitrile.

The title compound, C12H10Br2N2O2, represents an example of a planar π-con-jugated 2-aza-butadiene mol-ecule, which is both an inter-esting starting material for further organic transformations and a potential ligand in organometallic coordination chemistry. Its metric mol-ecular parameters are typical for the family of 2-aza-buta-1,3-dienes not substituted at the (CH) 3-position. In the crystal, the almost planar (r.m.s. deviation = 0.0658 Å) aza-diene mol-ecules form one-dimensional double-wide ribbons through inter-molecular halogen bonds (C-Br⋯O and C-Br⋯Br-C), which then stack in a slipped manner through weak C-H⋯Br and π-π inter-actions to generate a three-dimensional network.

Synthesis of Isoxazole and 1,2,3-Triazole Isoindole Derivatives via Silver- and Copper-Catalyzed 1,3-Dipolar Cycloaddition Reaction.

The CuI- or Ag2CO3-catalyzed [3+2] cycloaddition of propargyl-substituted dihydroisoindolin-1-one (3) with arylnitrile oxides 1a-d (Ar = Ph, p-MeC6H4, p-MeOC6H4, p-ClC6H4) produces in good yields novel 3,5-disubstituted isoxazoles 4 of the ethyl-2-benzyl-3-oxo-1-((3-arylisoxazol-5yl)methyl)-2,3-dihydro-1H-isoindole-1-carboxylate type. With aryl azides 2a-d (Ar = Ph, p-MeC6H4, p-OMeC6H4, p-ClC6H4), a series of 1,4-disubstituted 1,2,3-triazoles 6 (ethyl-2-benzyl-3-oxo-1-((1-aryl-1H-1,2,3-triazol-4-yl)methyl)-2,3-dihydro-1H-isoindole-1-carboxylates) was obtained. The reactions proceed in a regioselective manner affording exclusively racemic adducts 4 and 6. Compared to the uncatalyzed cycloaddition, the yields are significantly improved in the presence of CuI as catalyst, without alteration of the selectivity. The regio- and stereochemistry of the cycloadducts has been corroborated by an X-ray diffraction study of 4a, and in the case of 6a by XH-correlation and HMBC spectra.

Regio- and Stereoselective Synthesis of Spiropyrrolizidines and Piperazines through Azomethine Ylide Cycloaddition Reaction.

A series of original spiropyrrolizidine derivatives has been prepared by a one-pot three-component [3 + 2] cycloaddition reaction of (E)-3-arylidene-1-phenyl-pyrrolidine-2,5-diones, l-proline, and the cyclic ketones 1H-indole-2,3-dione (isatin), indenoquinoxaline-11-one and acenaphthenequinone. We disclose an unprecedented isomerization of some spiroadducts leading to a new family of spirooxindolepyrrolizidines. Furthermore, these cycloadducts underwent retro-1,3-dipolar cycloaddition yielding unexpected regioisomers. Upon treatment of the dipolarophiles with in situ generated azomethine ylides from l-proline or acenaphthenequinone, formation of spiroadducts and unusual polycyclic fused piperazines through a stepwise [3 + 3] cycloaddition pathway is observed. The stereochemistry of these N-heterocycles has been confirmed by several X-ray diffraction studies. Some of these compounds exhibit extensive hydrogen bonding in the crystalline state. To enlighten the observed regio- and stereoselectivity of the [3 + 2] cycloaddition, calculations using the DFT approach at the B3LYP/6-31G(d,p) level were carried out. It was found that this reaction is under kinetic control.

Crystal structure of tricarbon-yl(µ-di-phenyl-phosphido-κ(2) P:P)(methyl-diphenyl-silyl-κSi)bis(tri-phenyl-phosphane-κP)iron(II)platinum(0)(Fe-Pt).

The title compound, [FePt(C12H10P)(C13H13Si)(C18H15P)2(CO)3]·0.5CH2Cl2, represents an example of a phosphido-bridged heterobimetallic silyl complex; these are inter-esting precursors for the coordination and activation of small unsaturated organic mol-ecules. The µ2-PPh2 ligand spans the iron and platinum atoms, which are connected via a metal-metal bond of 2.7738 (4) Å. In contrast to most other complexes of the [(OC)3Fe(SiR 3)(µ-PR 2)PtL 2] family, where the iron-bound SiR 3 group is trans-arranged with respect to the µ2-PPh2 ligand, the SiPh2Me ligand is roughly collinear with the Fe-Pt vector [Si-Fe-Pt = 169.07 (3)°].

Reactivity of CuI and CuBr toward dialkyl sulfides RSR: from discrete molecular Cu4I4S4 and Cu8I8S6 clusters to luminescent copper(I) coordination polymers.

The 1D coordination polymer (CP) [(Me2S)3{Cu2(µ-I)2}]n (1) is formed when CuI reacts with SMe2 in n-heptane, whereas in acetonitrile (MeCN), the reaction forms exclusively the 2D CP [(Me2S)3{Cu4(µ-I)4}]n (2) containing "flower-basket" Cu4I4 units. The reaction product of CuI with MeSEt is also solvent-dependent, where the 1D polymer [(MeSEt)2{Cu4(µ3-I)2(µ2-I)2}(MeCN)2]n (3) containing "stepped-cubane" Cu4I4 units is isolated in MeCN. In contrast, the reaction in n-heptane affords the 1D CP [(MeSEt)3{Cu4(µ3-I)4}]n (4) containing "closed-cubane" Cu4I4 clusters. The reaction of MeSPr with CuI provides the structurally related 1D CP [(MeSPr)3{Cu4(µ3-I)4}]n (5), for which the X-ray structure has been determined at 115, 155, 195, 235, and 275 K, addressing the evolution of the metric parameters. Similarly to 4 and the previously reported CP [(Et2S)3{Cu4(µ3-I)4}]n (Inorg. Chem. 2010, 49, 5834), the 1D chain is built upon closed cubanes Cu4(µ3-I)4 as secondary building units (SBUs) interconnected via µ-MeSPr ligands. The 0D tetranuclear clusters [(L)4{Cu4(µ3-I)4}] [L = EtSPr (6), Pr2S (7)] respectively result from the reaction of CuI with EtSPr and n-Pr2S. With i-Pr2S, the octanuclear cluster [(i-Pr2S)6{Cu8(µ3-I)3}(µ4-I)2}] (8) is formed. An X-ray study has also been performed at five different temperatures for the 2D polymer [(Cu3Br3)(MeSEt)3]n (9) formed from the reaction between CuBr and MeSEt in heptane. The unprecedented framework of 9 consists of layers with alternating Cu(µ2-Br)2Cu rhomboids, which are connected through two µ-MeSEt ligands to tetranuclear open-cubane Cu4Br4 SBUs. MeSPr forms with CuBr in heptane the 1D CP [(Cu3Br3)(MeSPr)3]n (10), which is converted to a 2D metal-organic framework [(Cu5Br5)(µ2-MeSPr)3]n (11) incorporating pentanuclear [(Cu5(µ4-Br)(µ2-Br)] SBUs when recrystallized in MeCN. The thermal stability and photophysical properties of these materials are also reported.

Crystal structure of di-µ-iodido-bis-[(dimethyl sulfoxide-κO)(tri-phenyl-phosphane-κP)copper(I)].

The centrosymmetric dinuclear title compound, [Cu2I2(C2H6OS)2(C18H15P)2], represents the first example of a CuI complex ligated by an O-bound dimethyl sulfoxide ligand. In the crystal, the two tetrahedrally coordinated Cu(I) atoms are bridged by two µ2-iodido ligands in an almost symmetrical rhomboid geometry. The loose Cu⋯Cu contact of 2.9874 (8) Šis longer than the sum of the van der Waals radii of two Cu atoms (2.8 Å), excluding a significant cupriophilic inter-action in the actual dimer. C-H⋯O and C-H⋯I hydrogen bonding interactions as well as C-H⋯π(aryl) interactions stabilize the three-dimensional supramolecular network.

Formation of an unprecedented (CuBr)5 cluster and a zeolite-type 2D-coordination polymer: a surprising halide effect.

A unique pentanuclear cluster within a zeolite-type polymer ([Cu5(µ4-Br)(µ3-Br)2(µ2-Br)2](µ2-MeSPr)3)n (1; void space >81%) and a luminescent 1D ([Cu(µ3-I)]4(MeSPr)3)n polymer, 2, are formed when MeSPr reacts with CuBr and CuI.

Diethyl 2,2'-(1,4-phenyl-enedi-oxy)-diacetate.

In the title compound, C(14)H(18)O(6), a crystallographic center at the centroid of the aromatic ring generates the complete mol-ecule which is planar within 0.085 (1) Šfor the non-H atoms. In the crystal, weak C-H⋯O and C-H⋯π inter-actions link the molecules.

Reactivity of CuI and CuBr toward Et2S: a reinvestigation on the self-assembly of luminescent copper(I) coordination polymers.

CuI reacts with SEt(2) in hexane to afford the known strongly luminescent 1D coordination polymer [(Et(2)S)(3){Cu(4)(mu(3)-I)(4)}](n) (1). Its X-ray structure has been redetermined at 115, 235, and 275 K in order to address the behavior of the cluster-centered emission and is built upon Cu(4)(mu(3)-I)(4) cubane-like clusters as secondary building units (SBUs), which are interconnected via bridging SEt(2) ligands. However, we could not reproduce the preparation of a coordination polymer with composition [(Et(2)S)(3){Cu(4)(mu(3)-Br)(4)}](n) as reported in Inorg. Chem. 1975, 14, 1667. In contrast, the autoassembly reaction of SEt(2) with CuBr results in the formation of a novel 1D coordination polymer of composition [(Cu(3)Br(3))(SEt(2))(3)](n) (2). The crystal structure of 2 has been solved at 115, 173, 195, and 235 K. The framework of the luminescent compound 2 consists of a corrugated array with alternating Cu(mu(2)-Br)(2)Cu rhomboids, which are connected through two bridging SEt(2) ligands to a tetranuclear open-cubane Cu(4)Br(4) SBU, ligated on two external Cu atoms with one terminal SEt(2). The solid-state luminescence spectra of 1 and 2 exhibit intense halide-to-metal charge-transfer emissions centered at 565 and 550 nm, respectively, at 298 K. A correlation was also noted between the change in the full width at half-maximum of the emission band between 298 and 77 K and the relative flexibility of the bridging ligand. The emission properties of these materials are also rationalized by means of density functional theory (DFT) and time-dependent DFT calculations performed on 1.

4,4-Bis(4-methyl-phenyl-sulfan-yl)-1,1-diphenyl-2-aza-buta-1,3-diene.

In the title compound, C(29)H(25)NS(2), both the Cl atoms of the aza-diene precursor 4,4-dichloro-1,1-diphenyl-2-aza-buta-1,3-diene are replaced by two vicinal S-p-tolyl substituents attached to the terminal C atom of a π-conjugated 2-aza-butadiene array. The aza-diene chain is planar to within 0.01 Å. One of the phenyl rings seems to be slightly π-conjugated with the aza-diene core [dihedral angle 5.1 (2)°].

Chemistry of transition-metal clusters with mixed Sb/S ligands: evidence for a terminal Sb=S double bond in Cp*3Rh3Sb2S5 (Cp* = C5Me5).

The reaction of [Cp2*Rh2Cl4] (Cp* = C5Me5) with a slight excess of K(3)SbS(3) in boiling THF gave the neutral clusters [Cp*4Rh4S5] (1), [Cp*3Rh3Sb2S5] (2), and after salt metathesis [Cp*3Rh3SbSn]PF6 (3; n = 5 and 6). The structures of 1-3 are heterocubane clusters with CpRh, S, and Sb vertices but with sulfur inserted into one (1 and 2) or two (3) edges. X-ray diffraction analysis of 2 additionally reveals a very short Sb-S distance of 2.297(1) A within the novel mu3-Sb2S4 ligand. Density functional theory calculation of the model compounds [SSbS]3-, [HSSbS]2-, and [HSSbH2S]0 provided strong evidence for the existence of a stable terminal Sb=S double bond in 2.

Organometallic early lanthanide clusters: syntheses and X-ray structures of new monocyclopentadienyl complexes.

The reaction of Ln(BH(4))(3)(THF)(3) or LnCl(3)(THF)(3) with 1 equiv of KCp*' ligand (Cp' = C(5)Me(4)n-Pr) afforded the new monocyclopentadienyl complexes Cp*'LnX(2)(THF)(n) (X = BH(4), Ln = Sm, n = 1, 1a, Ln = Nd, n = 2, 1b; X = Cl, Ln = Sm, n = 1, 3a) and [Cp*'LnX(2)](n') (X = BH(4), n' = 6, Ln = Sm, 2a, Ln = Nd, 2b; X = Cl, Ln = Nd, 4b). All these compounds were characterized by elemental analysis and (1)H NMR. Crystals of mixed borohydrido/chloro-bridged [Cp*'(6)Ln(6)(BH(4))(12-x))Cl(x)(THF)(n')] (x = 10, n' = 4, Ln = Sm, 2a', Ln = Nd, 2b'; x = 5, n = 2, Ln = Sm, 2a' ') were also isolated. Compounds 2a, 2b, 2a', 2b', and 2a'' were structurally characterized; they all exhibit a hexameric structure in the solid state containing the [Cp*(3)Ln(3)X(5)(THF)] building block. The easy clustering of THF adducts first isolated is illustrative of the well-known bridging ability of the BH(4) group. Hexameric 2a was found to be unstable in the presence of THF vapors; this may be correlated to the opening of unsymmetrical borohydride bridges observed in the molecular structure.

Genuine heteroleptic complexes of early rare-earth metals: synthesis, X-ray structure, and their use for stereospecific isoprene polymerization catalysis.

Genuine heteroleptic neodymium and samarium complexes of formula [Cp*'Ln[(p-tol)NN](BH4)] (Cp*' = C5Me4(nPr), (p-tol)NN = (p-tol)NC(Me)CHC(Me)N(p-tol), Ln = Sm: 1a, Ln = Nd: 1b) have been synthesized for the first time. These unprecedented homologues of early lanthanocenes are prepared by a metathetic reaction between their monocyclopentadienylbisborohydrido precursors with the corresponding potassium diketiminate. Both complexes were obtained in good yields and were characterized by 1H NMR spectroscopy and elemental analysis. Complex 1 a has an non-solvated dimeric structure, as indicated by its crystallographic data. The chloroneodymium analogue [Cp*'Nd[(p-tol)NN](Cl)] (2b) was only obtained as a part of a mixture. Analysis of crystals of 2b by X-ray diffraction revealed a molecular structure very similar to that of 1a. Preliminary isoprene polymerization experiments were carried out with 1 b in the presence of an alkylmagnesium coactivator. The resulting bimetallic Nd/Mg system behaves as an efficient and highly stereospecific catalyst with the synthesis of trans-1,4-polyisoprene with more than 98% regularity. The control of the polymer structure is related to the steric hindrance around the lanthanide atom.