Cubane-like Structure Research Articles

Formation of new organometallic W/Cu/S clusters from reactions of [{(η 5-C 5Me 5)WS 3} 3Cu 7(MeCN) 9](PF 6) 4 with donor ligands. Crystal structures and optical limiting properties of [(η 5-C 5Me 5)WS 3Cu 3(Py) 6](PF 6) 2, [(η 5-C 5Me 5)WS 3Cu 3Br(PPh 3) 3](PF 6), and [(η 5-C 5Me 5)WS 3Cu 4(Py)Cl(dppm) 2](PF 6) 2

Treatment of a preformed cluster {(η 5-C 5Me 5)WS 3} 3Cu 7(MeCN) 9](PF 6) 4 ( 1) in MeCN with excess pyridine afforded a tetranuclear cationic cluster [(η 5-C 5Me 5)WS 3Cu 3(Py) 6](PF 6) 2 ( 2). On the other hand, reactions of 1 with excess PPh 3 under the presence of LiBr gave rise to the other tetranuclear cationic cubane-type cluster [(η 5-C 5Me 5)WS 3Cu 3Br(PPh 3) 3](PF 6) ( 3) while analogous reactions of 1 with dppm and LiCl followed by addition of excess pyridine generated an intriguing pentanuclear cationic cluster [(η 5-C 5Me 5)WS 3Cu 4(Py)Cl(dppm) 2](PF 6) 2 ( 4). Compounds 2– 4 were fully characterized by spectroscopy and X-ray crystallography. The cluster dication of 2 adopts an incomplete WS 3Cu 3 cubane-like structure while the cluster cation of 3 contains a WS 3Cu 3Br cubane-like structure. The structure of the cluster dication of 4 consists of an unique WS 3Cu 4Cl framework in which an open cubane-like WS 3Cu 3Cl fragment and a Cu(dppm) 2 fragment are connected by one Cu–Cl bond and two Cu–dppm–Cu bridges. The optical limiting (OL) properties of the MeCN solutions of 1– 4 were investigated with 7-ns laser pulses at 532 nm.

Vibrational frequencies and structural determination of Ge 4O 4

The vibrational frequencies and corresponding normal mode assignments of the germanium monoxide tetramer (Ge 4O 4) in T d symmetry are examined theoretically using the Gaussian03 set of quantum chemistry codes and compared against available experimental data. All normal modes were successfully assigned to one of two types of motion predicted by a group theoretical analysis (Ge–O stretch and Ge–O–Ge bend) utilizing the T d symmetry of the molecule. The molecule possesses a cubane-like structure.

Assembly of a Supramolecular Cube, [(Cp*WS3Cu3)8Cl8(CN)12Li4] from a Preformed Incomplete Cubane-like Compound [PPh4][Cp*WS3(CuCN)3

A supramolecular cube has been formed by linking WS3Cu3 clusters with bidentate ligands. Eight WS3Cu3 clusters, which have an incomplete cubane-like structure, serve as the three connecting nodes of the cube, while 12 bridging cyanide anions coordinated to copper centers lie along the edges of the cube. Eight chloride anions and four lithium cations are located inside the cube.

Crystal structures and nonlinear optical properties of new clusters [MOS 3Cu 3(PPh 3) 3{S 2P(OCH 2Ph) 2}] (M=Mo, W)

Two new isostructural O, O′-dialkyl dithiophosphate-containing sulfido clusters, MOS 3Cu 3(PPh 3) 3{S 2P(OCH 2Ph) 2}] (M=Mo ( 1); M=W ( 2)), were synthesized through reaction of [NH 4[MOS 3] with [CuS 2P(OCH 2Ph) 2]. They possess an incomplete cubane-like structure, in which the dithiophosphate ligand adopts a triply bridging role, employing one sulfur atom to bind to one Cu atom and the other to two Cu atoms. High third-order nonlinear optical properties of the two clusters were observed, and Z-scan data measured with 532 nm nanosecond laser pulses showed effective third-order optical nonlinearities α 2=0.78×10 −10 and 1.16×10 −10 m W −1, and n 2=−7.8×10 −18 and 4.0×10 −18 m 2 W −1, respectively, for DMF solution of compound 1 and DMF solution of 2. These two clusters exhibit large optical limiting performance with limiting threshold values of 220 mJ cm −2 for 1 and 600 mJ cm −2 for 2.

Structure and ion exchange properties of tunnel type titanium silicates

Abstract A large number of titanium silicates are known to exist in the mineral realm and recently a considerable literature has developed concerned with the synthesis and properties of these and related compounds. This paper describes two such families that have tunnel structures filled with cations that may easily be exchanged. A sodium titanosilicate of ideal formula, Na2Ti2O3(SiO4)2·2H2O, is tetragonal and built up of Ti4O4 cubane-like structures linked together by silicate groups in the a and b directions in the form of a square. In the c-axis direction, the cubane groups are linked by oxo-groups to form a framework enclosing tunnels parallel to the c-axis direction. The several ion exchange sites were identified based upon X-ray diffraction studies and the reason for the great affinity of this compound for Cs+ elucidated. The second family of compounds have the general composition M3H(TiO)4(SiO4)3·4H2O (M=alkali metal cation) and have the pharmacosiderite structure. The sodium or potassium phases are selective for Sr2+ and Cs+. These compounds are cubic and have similar Ti4O4 cubane-like groups. In this case, the connectivity via silicate groups extends along all three crystallographic axes equally. This change in crystal system has a profound effect upon the ion exchange behavior. This effect, as well as the effect of germanate substitutions for silicate, will be described.

Synthesis, crystal structure and nonlinear optical properties of two new cluster compounds: [WCu 3S 4(PPh 3) 3{S 2P(OCH 2Ph) 2}] and [WAg 3OS 3(Ph 3P) 3{S 2P(OPr i) 2}

Two new O, O′-dialkyl dithiophosphate-containing sulfido clusters, [WCu 3S 4(PPh 3) 3{S 2P(OCH 2Ph) 2}] 1 and [WAg 3OS 3(Ph 3P) 3{S 2P(OPr i) 2}] 2, were synthesized through reactions of [NH 4] 2[WS 4] with [CuS 2P(OCH 2Ph) 2] and [NH 4] 2[WOS 3] with [AgS 2P(OPr i) 2], respectively. Their crystal structures and nonlinear optical properties are reported. The X-ray crystallographic structure of 1 is an incomplete cubane-like structure, the dithiophosphate ligand adopts a triply bridging role, employing two sulfur atoms to coordinate to the three Cu atoms: one sulfur atom binds to one Cu atom, another sulfur atom to two other Cu atoms. The structure of 2 contains a half-open cubane-like cluster core, the dithiophosphate ligand acts as a bidentate ligand and the two S atoms of the di-isopropyl dithiophosphato ligand coordinate to two Ag atoms, respectively. Using a Z-scan technique with 532 nm laser radiation, both the real and imaginary parts of third-order nonlinear susceptibility of clusters 1 and 2 were determined.

Crystal and molecular structure of potassium, ammonium and dicyclohexylammonium salts of (2-oxopropyl) phosphonic acid in monoionized state

The crystal and molecular structures of potassium ( I), ammonium ( II) and dicyclohexylammonium ( III) (2-oxopropyl) phosphonates were determined by X-ray methods. For all three compounds the monoionized anion has a similar conformation, with the phosphonate group projected out of the ketone backbone. The crystals of I and II contain two symmetry-independent anions and cations in the asymmetric unit, the anions are arranged in tetramers by strong hydrogen bonds. In the crystals of III the anions are arranged in hydrogen-bonded dimers. The anions differ mostly in the orientation of the hydroxyl group, being + gauche for Ia, IIb and III, nearly antiperiplanar for Ib, and — gauche for IIa, with regard to the C(CO) atom. In all cases the hydrogen bonds between phosphonate groups are strong. The hydrogen bonds between anions and ammonium and dicyclohexylammonium cations display normal strength. In all crystals the carbonyl O atom is an acceptor of hydrogen from the methyl or methylene group. The K-cations in I are hexaccordinated and four of them are arranged in a cubane-like structure connected through four phosphonate O atoms.

REACTIONS OF CLUSTER COMPOUND [(C2H5)4N]4[Mo2O2S6Cu6I4Br2]: Synthesis, Crystal Structures of [MoOS3Cu3(AsPh3)3I]-2DMF and MoOS3Cu3(PPh3)3I

The title compounds [MoOS3Cu3(AsPh3)3I]-2DMF (II) and MoOS3Cu3(PPh3)3I (III) were obtained by reaction of twin-nest shaped cluster [(C2H5)4N]4[Mo2O2S6Cu6I4Br2] (I) with AsPh3 and PPh3 in solution, respectively. The compounds have been studied by single crystal X-ray methods. The structure of (II) has been refined to show a cubane-like structure containing a {MoS3Cu3} core and AsPh3 ligands attached to three Cu atoms. Reaction properties of (I) are also described and discussed.

Syntheses and crystal structures of two heterometallic incomplete cubane-like clusters: [-MoAg 2S 3C 5H 5NS-(PPh 3) 2(S)]·CH 2Cl 2 and [-WAg 2Se 3C 5H 5NS-(PPh 3) 2(Se)]·CH 2Cl 2

Two incomplete cubane-like clusters, [{MoAg 2S 3C 5H 5NS}(PPh 3) 2(S)]·CH 2Cl 2 ( I) and [{WAg 2Se 3C 5H 5NS}(PPh 3) 2(Se)]·CH 2Cl 2 ( II), were obtained from the reaction of MoS 4Ag 2(PPh 3) 3 and WSe 4 Ag 2(PPh 3) 3 with excess C 5H 5NS in CH 2Cl 2 solvent. The X-ray crystallography analysis shows that I and II have incomplete cubane-like structures, in which the Mo(W) and Ag atoms are tetrahedrally coordinated.

Molecular architecture of copper (I) thiometallates: synthesis and characterization of [ReS4Cu3Cl5]3-, a geometry derived from the single cubane-like structure

The new rhenium-copper heteronuclear complex [NEt4]3[ReS4C3Cl5]2, was obtained as black crystals in 65% yield, from the reaction of [NEt4[[ReS4], [NEt4][CuCl2], and [NEt4][Cl] at - 20°C in acetone, while at room temperature without additional chloride [NEt4]2[ReS4Cu3Cl4]1 crystallized as black crystals in 60% yield. Crystal data for2: space group Pl,a=10.331(4) A,b=14.261(2) A,c= I4.458(3) A, α=78.55(1)°, β=81.83(3)°, γ=83.66(3)°,Z=2, 6480 reflections;R=0.058. For1: space group C2/c,a=20.969(5)A,b=12.955(5)A,c=22.827(8)A, β=91.16(2)°, Z=8, 3208 reflections,R = 0.052, The geometry of2 can be viewed as restllting from the opening of the cubane-like structure of1.

Synthesis, crystal structure and non-linear optical properties of two new cluster compounds, [MoCu3OS3(PPh3)3{S2P(OBu)2}] and [MoAg3S4(PPh3)3{S2P(OBui)2}

Two novel O,O′-dialkyl dithiophosphate-containing Group 11–Group 16 sulfido clusters, [MoCu3OS3(PPh3)3{S2P(OBu)2}]1 and [MoAg3S4(PPh3)3{S2P(OBui)2}]2, have been synthesised through reactions of [NEt4]2[MoOS3] with Cu[S2P(OBu)2] and [NEt4]2[MoS4] with Ag[S2P(OBui)2] respectively in dichloromethane and in the presence of PPh3. The clusters crystallise in orthorhombic and triclinic forms respectively. The X-ray crystallographic structure determinations show that both clusters have a partial open cubane-like structure. The dithiophosphate ligands adopt a triply bridging role, employing two sulfur atoms to co-ordinate to the three Group 11 metal (M) atoms: one sulfur atom binds to one M atom, the other to two other M atoms. The clusters are soluble in common organic solvents and exhibit both non-linear absorption and non-linear refraction (self defocusing). Cluster 2 also exhibits a sizeable optical limiting effect.

Synthesis and characterization of alkoxo-oxygen-bridged copper(II) complexes having disc- and rod-like shapes

A series of copper(II) complexes with tridentate Schiff bases, obtained by the 1:1 condensation of a 4-(p-n-alkoxybenzoyloxy)salicylaldehyde and an aminoalcohol have been prepared and characterized, where the n-alkoxy group is n-propyloxy, n-butyloxy, n-hexyloxy, n-octyloxy, n-hexadecyloxy or n-octadecyloxy and the aminoalcohol is 2-aminoethanol, 3-aminopropanol, (R)- or (S)-2-amino-4-methylpentanol. The nineteen complexes thus synthesized can be classified into two groups, A and B; group A contain a 3-aminopropanol residue and B one of the remaining aminoalcohol residues. Group A members are reddish violet and almost diamagnetic, and it is deduced that these molecules are rod-like in shape and involve a binuclear Cu2O2 central core; group B are blue and paramagnetic, and likely to have a tetranuclear Cu4O4 central core of cubane-like structure and overall disc-like molecular shape. Polarized microscopic, differential scanning calorimetry, and heating X-ray diffractometry measurements were made to study the thermotropic mesomorphism. Polymorphic transitions have been characterized for representative complexes from groups A and B.

The synthesis, and properties of Fe/Mo/S clusters with MoFe 3S 4 cubane subunits, Mo bound bidentate oxalate ligands and terminal or bridging cyanide ligands. Structural characterization of (Et 4N) 3[(C 2O 4)(CN)MoFe 3S 4Cl 3] and (Et 4N) 5{[C 2O 4)MoFe 3S 4Cl 2] 2(μ-CN)(μ-S)}

The reaction of (Et 4N) 3[(C 2O 4)MoFe 3S 4Cl 4] ( I) with (Et 4N)CN affords [(C 2O 4)(CN)MoFe 3S 4Cl 3] 3− ( IV) in nearly quantitative yields. The reaction of I with 0.5 eq. of (Et 4N)CN and 0.5 eq. of a source of S 2− affords the doubly-bridged double-cubane {[(C 2O 4)MoFe 3S 4Cl 2] 2(μ 2-CN)(μ 2-S)} 5− ( V) in ≈30% yield. Single crystal X-ray structures were determined for IV and V. The mean FeFe, FeS and FeCl bond distances in IV at 2.713(3), 2.270(5) and 2.214(5) Å, are typical for MoFe 3S 4 cubane-like structures. The MoC(N) and CN bond lengths are found at 2.19(2) and 1.04(2) Å, respectively. The pentaanion in V consists of two doubly-bridged cubane subunits bridged by μ 2-CN − ligand through the Mo atoms and a μ s-S 2− through two Fe atoms. The Mo⋯Mo and Fe⋯Fe(intercube) distances and the Feμ 2-SFe angle are found at 5.267(4), 3.443(7) and 104.1(4)°. The spectroscopic and electrochemical features of IV and V are discussed.

Synthesis and structural characterization of two novel heteronuclear cluster compounds, [NEt 4] 4[WS 4Cu 5Br 7] and

The title compounds have been obtained by the reaction of [NH 4] 2(WS 4, CuBr, [NEt 4] 4Br and [Bu n 4N]Br in the solid state ( 1), or by the reaction of [NH 4] 2[WS 4], CuI and [Bu n 4N]I in the solid state and the pyridine substitution of the solid-state product in acetonitrile ( 2). X-ray diffraction analysis confirms that in the structure of 1 five of the six edges of the [WS 4] 2− tetrahedron are coordinated by CuBr units forming an open, double cubane-like structure, which possesses crystallographically imposed C 2 symmetry. The structure of 2, which possesses a crystallographic 4 symmetry axis situated at the tungsten atom, consists of a tetrahedral WS 4 core enveloped by an octahedral array of six copper atoms, forming a WS 4Cu 6 aggregate. Linked by Cu eqICu eq bridges, this aggregate connects with its nearest neighbours and develops a two-dimensional network. The substitution reactions of the solid-state product with pyridine are discussed.

Application of the hydro(solvento)thermal technique to the synthesis of metal carbonyl chalcogenide clusters. 2. Synthesis and x-ray structures of [[Fe4Te4(CO)10]2(Te2)]2- and [[Fe2Se(CO)6]2(Se2)]2-

The hydrothermal reaction of Fe(CO)[sub 5] with Na[sub 2]Te[sub 2] in the presence of Ph[sub 4]PCl at 110[degrees]C forms (Ph[sub 4]P)[sub 2][[l brace]Fe[sub 4]Te[sub 4](CO)[sub 10][r brace][sub 2](Te[sub 2])] (I) while the reaction of Fe(CO)[sub 5] with Na[sub 2]Se[sub 2] in superheated methanol at 80[degrees]C results in (Ph[sub 4]P)[sub 2][[l brace]Fe[sub 2]Se(CO)[sub 6][r brace][sub 2](Se[sub 2])] (II). The structures of (I) and (II) were determined by X-ray single-crystal analysis. (I) crystallizes in the space group P[bar 1], and (II) in the space group P2[sub 1]/n. The [[l brace]Fe[sub 4]Te[sub 4](CO)[sub 10][r brace][sub 2](Te[sub 2])][sup 2[minus]] anion in (I) forms a ditelluride, Te[sub 2][sup 2[minus]], bridged double cubane-like structure with eight iron atoms in two Fe[sub 4]Te[sub 4] cubes being octahedrally-coordinated by briding tellurium ligands and terminal CO groups. The [[l brace]Fe[sub 2]Se(CO)[sub 6][r brace][sub 2](Se[sub 2])][sup 2[minus]] molecule in (II) adopts a double butterfly' conformation caused by an intramolecular Se-Se linkage between two Fe[sub 2]Se[sub 2](CO)[sub 6] units. All iron atoms in this structure have a distorted octahedral geometry achieved by selenium ligands, CO groups, and a Fe-Fe single bond. The average Fe-Te bond distance is 2.619(4) [Angstrom], and Fe-Se = 2.386(17) [Angstrom]. 30 refs., 4 figs., 5 tabs.

Heterobimetallic aggregates derived from the double cubane-like structure (NMe 4) 4[MS 4(CuCl) 5Cl 2] (MMo, W)

Nucleophilic substitutions in the double cubane-like structures [MS 4(CuCl) 5Cl 2] 4− (M=Mo, W) are complicated by elimination reactions. With NCS − an edge-elimination process gave the [MS 4(CuNCS) 4] 2− anion whereas a face-elimination by PPh 3 led to the monocubane structure [MS 4(CuPPh 3) 4Cl]. Substitution by bipyridine produced the lacunary [MS 4Cu 3.75Cl 1.75bipy 2]. The different species were characterized by X-ray diffraction studies.

Synthesis and X-ray crystal structures of the one-dimensional ribbon chains [MOBu t·Bu tOH]∞ and the cubane species [MOBu t] 4 (M = K and Rb)

The series [MOBu t·Bu tOH]∞ (M = K, Rb and Cs) have been prepared by the reaction of M with Bu tOH in THF. Single-crystal X-ray diffraction studies revealed for M = K or Rb that [MOBu t·Bu tOH]∞ crystallizes from tetrahydrofuran-n-pentane at −20°C in the triclinic space group P 1 , with unit cell dimensions [K, Rb]: a = 9.862(3), 9.886(2) Å; b = 9.929(4), 9.914(2) Å; c = 6.330(2), 6.640(1) Å; β = 90.66(2), 90.46(1)° and Z = 2, as a one-dimensional chain linked by hydrogen-bonding. The strong hydrogen-bonding within the chain O(2)O(7) (2.46, 2.44 Å) also results in a near linear O(7)HO(2) angle (167.4, 172.61°) with the hydrogen atom closer to O(7) (1.22, 1.18 Å), than O(2) (1.24, 1.27 Å). These alcohol adducts may be readily converted into the compounds [MOBu t] 4 (M = K, Rb and Cs) by sublimation. Single-crystal X-ray diffraction studies reveal for M = K or Rb, that [MOBu t] 4 crystallizes from toluene at −20°C in the cubic space group P 4 3 M; with unit cell dimensions [K, Rb]; a = 8.372(1), 8.514(1) Å, and Z = 4, as cubane structures. Within the cubane-like structures the OMO angles are found to deviate only slightly from 90°, with OMO (90.18, 89.11°) and MOM (89.82, 90.89°) for M = K and Rb, respectively. The alcohol adducts undergo an alkoxide ligand exchange process that is rapid on the 1H NMR time scale at room temperature.

BiCo heteronuclear carbonyl compounds. Synthesis and crystal structure of the cubane-like species [Co(CO) 3(μ 3-Bil)] 4

The compound [Co(CO) 3(μ 3-Bi)] 4 has been obtained by prolonged pyrolysis of [BiCo(CO) 4 3] in refluxing tetrahydrofuran. This species, isomorphous with the analogous [Co(CO) 3(μ 3-Sb)] 4, crystallizes in the tetragonal space group I4 d1/ amd (No. 141) with a 14.731(3), c 10.574(3) Å and Z = 4. The structure was refined by full-matrix least-squares, on the basis of 447 significant unique reflections, to a final R value of 0.032. The compound has a cubane-like structure, with four tetrahedrally disposed Co(CO) 3 units triply bridged by four Bi atoms. The BiCo bonds have a mean value of 2.745 Å. Each cobalt atom exhibits a highly distorted octahedral coordination, with BiCoBi and CCoC angles of mean value 75.48 and 101.1°. The Co…Co contacts are definitely non-bonding (mean 4.291 Å). the non bonding Bi…Bi interactions (mean 3.360 Å) are particularly short. The mean values of the CoC and CO bond lengths are 1.78 and 1.19 Å, respectively.

The crystal structure of an incomplete cubane-like trinuclear tungsten cluster {[W 3S 4]·[S 2P(OC 2H 5) 2] 3·μ 2-CH 3COO·C 5H 5N}·0.5HCON(CH 3) 2

The title compound crystallizes in the triclinic space group P 1 with the following unit cell dimensions: a = 10.434 (5) Å; b = 12.423 (5) Å; c = 17.575 (7) Å; α = 102.58 (4)°, β = 91.61 (3)°; γ = 105.94 (4)°; Z = 2, V = 2128.5 Å 3; D c = 2.20 g cm −3; M n = 1410.18; F (000) = 1340; μ m = 88.9 cm −1; Mo K α radiation (λ = 0.71073 Å); R = 0.067 for 5728 reflections having intensities within the range I ⩾ 3σ( I). There are three WW bonds: W(1)–W(2) = 2.753 Å, W(1)–W(3) = 2.684 Å and W(2)–W(3) = 2.743 Å in the cluster core [W 3S 4], which has an incomplete cubane-like structure with a loosely liganded C 5H 5N.

Chemistry of chromium-selenium complexes. Thermolytic degradation of Cp 2Cr 2(CO) 4Se, and the crystal structures of the cubane-like clusters Cp 4Cr 4(μ 3-CO) 2(μ 3-Se) 2 and Cp 4Cr 4(μ 3-O) 2(μ 3-Se) 2

Thermolysis of Cp 2Cr 2(CO) 4Se ( 1) solution gave initially Cp 4Cr 4(CO) 2Se 3 ( 3), and a thermally labile unidentified species, which on further degradation afforded a mixture of products, from which more of 3, and the cubane-like complexes Cp 4Cr 4(CO) 2Se 2 ( 2) and Cp 4Cr 4O 2Se 2 ( 4) were isolated. A more prolonged thermolysis in THF yielded Cp 4Cr 4Se 4 ( 5) as the main product. Crystal data: 2, monoclinic, space group C2/ c, a 17.656(5), b 8.232(1), c 18.079(6) Å, β 126.15(2)°, Z = 4, R = 0.075 for 1499 observed Mo- K α data; 4, monoclinic, space group P2 1/ c, α 14.08(1), b 10.306(8), c 15.212(6) Å, β 103.55(2)°, Z = 4, R = 0.082 for 1711 observed Mo- K α data. Both complexes possess a cubane-like structure with triply bridging Se and CO or O ligands at alternating corners of the cuboid.