Synthesis and crystal structure of ammonium (picrate) (dibenzo-18-crown-6)

NH₄(Pic)(DB18C6) (Pic=picrate and DB18C6=dibenzo-18-crown-6), (C₂₆H₃₀N₄O₁₃) FW 606.56, arthorhombic,Pmn2₁,a=26.045(5),b=12.055(3),c=8.982(3) Å,V=2820(1) ų,Z=4,D _c =1.429 g/cm³, CuK, =1.54184 Å, (CuK)=9.5 cm^–1,F(000)=1272,T=298 K. The structure has been refined toR=0.0475 for 2617 unique observed reflections. In the lattice the 1:1 complex exists as a 2:2 dimer in which the crown are coupled through the Pic anions and NH₄ ⁺ cations. The asymmetric unit consists of two independent half crown ethers of which two opposite O atoms are on the mirror plane, two half ammonium cations of which the N and two H atoms are also on the mirror plane while the Pic anion is in a general position. Relative to each other, the corwn ethers are shifted by about 7.3 Å alongb and 1 Å alongc. The 1:1 sandwich of NH₄ with DB18C6 and Pic on dimerisation becomes a club pseudo-sandwich with three phenyl rings on either side of the mirror plane, thus forming a nearly parallel stack with a 3.6 Å inter-ring distance. The NH₄ ions hold the structure; two H atoms on the mirror plane are hydrogen-bonded to the opposite oxygens of the crown located on the purely aliphatic part of the ring (2.10(1), 2.06(3) and 2.26(3), 2.05(1) Å) for the two independent crowns, respectively, while the other two H atoms form mirror-related bifurcated hydrogen bonds with the phenoxide oxygen (1.99(1) and 2.01(1) Å) and theo-nitrogen oxygen (2.44(2) and 2.34(1) Å) of the picrates. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82037 (29 pages)     

Crystal Structure of Bis(dibenzo-18-crown-6)rubidium Triiodide

Crystalline bis(dibenzo-18-crown-6)rubidium triiodide complex [Rb(DB18C6)₂]⁺ · I₃ ^– (I) is synthesized and its structure is studied by X-ray diffraction analysis. The structure of I (space group Pnma, a = 23.854 Å, b = 23.612 Å, c = 7.863 Å, Z = 4) is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 against 3990 independent reflections (CAD4 automated diffractometer, MoK ). Structural units of crystal I are the I₃ ^– anions and [Rb(DB18C6)₂]⁺ cations. The crystal has the structure intermediate between that of a standard host–guest complex and a sandwich complex. In the structure of complex I, the crystallographic plane with symmetry m passes through the I₃ ^– anion (perpendicularly to its axis) and complex cation. The coordination polyhedron of the Rb⁺ cation is a strongly distorted hexagonal pyramid with the O atom of one crown ligand at the axial vertex and a base of six O atoms of another DB18C6 crown ligand.     

Crystal Structure of Triaqua(1,10-diaza-18-crown-6)chlorobarium Chloride

The crystal structure of triaqua(1,10-diaza-18-crown-6)chlorobarium chloride [Ba(DA18C6)Cl(H₂O)₃]⁺Cl^–(I) is studied by X-ray diffraction analysis: space group Pnma, a= 14.912, b= 13.590, c= 10.456 Å, Z= 4. Structure Iis solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation: R= 0.079 for all 3194 measured independent reflections (CAD-4 diffractometer, MoK ). Crystal Iexists as complex guest–host cations and Cl^–anions connected via interionic hydrogen bonds. The cations and anions are located in the msymmetry plane. The Ba²⁺ion (coordination number 10) is in the cavity of the DA18C6 macrocycle and is coordinated by its six heteroatoms (2N + 4O) and also by the Cl^–anion and two O atoms of two water molecules from one side of the macrocycle and by the O atom of the third water molecule from another side. The DA18C6 ligand in Ihas the conformation of a crown with an approximate D _3d symmetry.     

Crystal Structure of the Diaqua(1,10-Diaza-18-Crown-6) (Tetrafluorosuccinato-O)barium Complex

The diaqua(1,10-diaza-18-crown-6)(tetrafluorosuccinato-O)barium complex [Ba(DA18C6)(C₄F₄O₄)(H₂O)₂] (I) is synthesized and studied using X-ray diffraction analysis: space group P2₁/n, a = 16.342 Å, b = 8.989 Å, c = 17.087 Å, = 107.09°, Z = 4. The structure was solved by the direct method and refined by the full-matrix least squares method in anisotropic approximation to R = 0.075 for all 3515 unique reflections (CAD4 automated diffractometer, MoK ). Complex I exists in the crystal as individual host–guest molecules of the aforementioned composition. The Ba²⁺ cation (coordination number 9) is located in the void of the DA18C6 macrocycle and is coordinated by its six O and N heteroatoms. It is also coordinated by the O atom of the tetrafluorosuccinate ligand and the O atom of the water molecule on one side of the macrocycle and by the O atom of the second water molecule on the other macrocycle side. The DA18C6 ligand has a crown conformation with approximate D _3d symmetry. The complex molecules in the crystal are combined into infinite two-dimensional layers by intermolecular hydrogen bonds.     

Crystal structure of supramolecular complexes formed by 18-crown-6 andcis-anti-cis-dicyclohexano-18-crown-6 (host) with 3,4-diaminofurazane (guest)

An X-ray—diffraction study is reported for two molecular complexes containing 3,4-diamino-1,2,5-oxadiazole as guest (G) with 18-crown-6 (18-C-6) andcis-anti-cis-dicyclohexano-18-crown-6 (DCH-6B) as host. Both complexes are of the polymeric-chain structure with the guest molecule bridging two crown neighbours. ComplexI: [18-C-6*G*H₂O], 111, monoclinic,P2₁/n,a=8.171(1),b=15.042(2),c=16.209(6) Å, =101.15(2)°, finalR-factor 0.068. ComplexII: [DCH-6B*G], 11, monoclinicC2/c,a=21.212(4),b=9.380(2),c=13.049(3) Å, =108.61(3)°, finalR 0.047.     

Synthesis and crystal structure of aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(perchlorato-O)potassium perchlorate

A new compound, aqua(dibenzo-18-crown-6)potassium (dibenzo-18-crown-6)(perchlorato-O)potassium perchlorate ([K(DB18C6)(H₂O)]⁺ · [K(ClO₄)(DB18C6)] · ClO ₄ ^? ; compound I) is synthesized and studied by X-ray crystallography. The crystals are triclinic: a = 9.050 Å, b = 9.848 Å, c = 26.484 Å, α = 82.87°, β = 84.16°, γ = 77.93°, Z = 2, space group P $\bar 1$ . The structure is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.058 for 5960 independent reflections (CAD4 diffractometer, λMoK _α radiation). A complex cation [K(DB18C6)(H₂O)]⁺ and a complex molecule [K(ClO₄)(DB18C6)] are of the host-guest type; they are linked into a dimer through two K⁺ → π(C) bonds formed by one of the two K⁺ cations with two C atoms of the benzene ring of the DB18C6 ligand from the adjacent complex. Both DB18C6 ligands in I have a butterfly conformation with approximate symmetry C _2v .     

Syntheses,crystal structures,and characterizations of two novel cubane-like and double cubane-like molybdenum-copper-sulphur clusters {MoCu3S3(S2COEt)}(O)(Ph3P)3 and {Mo2Cu6S6(SCMe3)2}(O)2(Ph3P)4

Two novel heterometallic cubane-like and double cubane-like clusters, {MoCu₃S₃(S₂COEt)}(O)(Ph₃P)₃ I and {Mo₂Cu₆S₆(SCMe₃)₂}(O)₂(Ph₃P)₄ II, were synthesized by reaction of {MoCu₂S₃}(O)(Ph₃P)₃ with CuS₂COEt and CuSCMe₃, respectively. ClusterI crystallized in the triclinic space group (2) witha=12.766(6) Å,b=22.904(5) Å,c=10.522(3) Å, =99.86(2)°, =109.68(2)°, =86.84(3)°,V=2854(2) ų,Z=2,R=0.049 for 6622 observed reflections (I>5(I)) and 410 variables. ClusterII crystallized in the triclinic space group (2) with dimensionsa=14.212(4) Å,b=14.725(5) Å,c=12.396(8) Å, =110.32(4)°, =90.40(5)°, =62.88(2)°,V=2129(2) ų,Z=1,R=0.039 for 6020 observed reflections (I>3(I)) and 461 variables. ClusterI consists of a neutral cubane-like molecule with the core {MoCu₃S₃(S₂COEt)}²⁺, in which one corner of the cubane-like core is a novel triply bridging bidentate 1,1-dithiolato (xanthate, S₂COEt^–) ligand. ClusterII is a double cubane-like one, in which two cubane-like cores {MoCu₃S₃(SCMe₃)}²⁺ are connected by two Cu-S bonds of the triply bridging monothiolato (SCMe ₃ ^– ) ligand. Two different pathways of unit construction from a small heterometallic cluster {MoCu₂S₃}(O)(Ph₃P)₃ have been outlined. Comparisons of the selected bond lengths and bond angles for the cubane-like core {MoCu₃S₃ X} (X=Cl^–, Br^–, S₂COEt^–, SCMe ₃ ^– ) are given. Spectroscopic properties of the title clusters are also reported.     

Uncommon Behavior of Copper(I) Tetrafluoroborate and Perchlorate in [Cu(DAF)(H2O)]BF4and [Cu(DAF)(ClO4)] π-Complexes (DAF—Diallyl Formamide)

Crystals of [Cu(DAF)(H₂O)]BF₄(I) and [Cu(DAF)(ClO₄)] (II) (DAF is diallyl formamide) were synthesized by an alternate-current electrochemical method, and their structures were determined (MoK radiation, 1247 and 859 independent reflections with I 2(I), R= 0.043 and 0.032 for Iand II, respectively). The complexes crystallize in space group P2₁/n, Z= 4. For I, a= 10.782(3) Å, b= 12.096(5) Å, c= 9.185(3) Å, = 103.62(3)°, and V= 1164.2(7) ų; for II, a= 10.064(3) Å, b= 10.753(6) Å, c= 10.002(3) Å, = 87.52(4)°, and V= 1081.4(8) ų. The copper atom in structures Iand IIcoordinates both C=C bonds in one DAF molecule and oxygen atom of the amide group of another DAF molecule, as well as an oxygen atom of H₂O (in I) or ClO₄(in II) in the axial position. The uncommon behavior of the anions in structures Iand IIis explained by their different values of Pierson hardness.     

Synthesis and X-ray structural analysis of a unique Co-crystallization complex of [NaSal]2DB24C8 and [KSal]2DB24C8

Sodium salicylate (NaSal where Sal=2-hydroxybenzoate), when mixed with dibenzo-24-crown-8 (DB24C8) yields a bimetallic complex [NaSal]₂DB24C8 in most polar organic media, while potassium salicylate (KSal) under similar conditions shows a tendency to yield 11 or 21 complexes depending upon medium or synthesis. However, the presence of both NaSal and KSal together results in a unique mixed cation complex of composition NaKSal₂DB24C8. This product melts sharply (190-92°C) without decomposition, displays IR spectral characteristics comparable to those of [Na(Sal)]₂DB24C8, and is stable in aqueous media as shown by the detectable cation effect on the UV absorption bands of Sal and DB24C8. Single crystal X-ray analysis of NaK(Sal)₂DB24C8 reveals that the system represents a co-crystallization complex of individual (KSal)₂DB24C8 and (NaSal)₂DB24C8 molecules. The crystals are monoclinic,P2₁/c,a=19.976(2) Å,b=9.031(1) Å,c=25.541(5) Å,=122.065(9)°, ų,T=298 K,Z=2+2, CuK =1.5418 Å, and 2 (2.5°–100°). FinalR factor for the 3012 observed reflections (F>3) is 0.092. Both the Na₂- and K₂-molecules possess crystallographic centers of symmetry with one metal and its associated anion on each side of the crown ring. However, the conformations of the crowns are very different in the two molecules, with the K₂-crown being nearly planar and the Na₂-crown being quite puckered. Four oxygen atoms from the DB24C8 (KO, 2.680–2.908 Å) and three carboxyl oxygen atoms (KO, 2.472–2.708 Å) from separate salicylate ions coordinate with each potassium. Three oxygens from the crown (NaO, 2.536–2.65 Å) and three carboxyl oxygens (NaO, 2.31–2.563 Å) coordinate with each sodium. The salicylate ions lie on opposite sides and nearly perpendicular (77.2°, Na₂-molecule; 82.7° K₂-molecule) to each crown but coordinate to both of the metal ions within a molecule. The K⁺K⁺ and Na⁺Na⁺ distances in the respective molecules are 3.95 and 3.34 Å. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82044 (18 pages).     

Palladium Clusters Pd4(SEt)4(OAc)4and Pd6(SEt)12: Structure and Properties

Palladium clusters Pd₄(SEt)₄(OAc)₄(I) and Pd₆(SEt)₁₂(II) were synthesized and studied. Their structure was determined by X-ray diffraction analysis. For I, a= 9.774(2) Å, b= 10.821(2) Å, c= 13.061(3) Å, = 92.88(3)°, V= 1379.6(5) ų, (calcd.) = 2.182 g/cm³, space group P2₁/n, Z= 4, N _ref= 1558, and R= 0.031; for II, a= 10.581(1) Å, b= 10.584(2) Å, c= 11.478(2) Å, = 101.62(1)°, = 104.95(1)°, = 106.74(1)°, V= 1135.2(4) ų, (calcd) = 2.007 g/cm³, space group P1, Z= 1, N _ref= 2828, and R= 0.022. In cluster I, four Pd atoms form a planar cycle. The neighboring palladium atoms are bound by two acetate or by two mercaptide bridges, the Pd···Pd distances being 3.036–3.195 Å. In cluster II, Pd atoms form a planar six-membered cycle with Pd···Pd distances of 3.083–3.127 Å. The neighboring palladium atoms are bound by two mercaptide bridges. The formation of analogous clusters in solution was confirmed by IR spectroscopy.     

Crystal Structure of the Bis(Picrato-O,O")Tetraaquacalcium Complex with 18-Crown-6, [Ca(Pic)2(H2O)4] · 18C6

The crystal structure of the bis(picrato-O,O")tetraaquacalcium complex with 18-crown-6, [Ca(Pic)₂(H₂O)₄] · 18C6 (I), was studied using X-ray diffraction analysis: space group C2/c, a= 20.446 Å, b= 14.985 Å, c= 16.163 Å, = 135. 41°, Z= 4. The structure of Iwas solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R= 0.047 over all 3044 measured independent reflections (CAD4 automated diffractometer, MoK radiation). In the crystal, Iis not a guest–host complex but exists as individual [Ca(Pic)₂(H₂O)₄] and 18C6 molecules joined by intermolecular hydrogen bonds and van der Waals interactions. The Ca²⁺cation (CN 8) is located on a twofold crystallographic axis, its coordination polyhedron being a distorted square antiprism. The centrosymmetrical 18C6 molecule has a crown conformation with approximate D _3d symmetry and has six neighboring water molecules (three on each side of its mean plane), which form eight hydrogen bonds involving all six O atoms of 18C6.     

Ammonium (18-Crown-6)(Triphenylphosphine Oxide) Perchlorate: Synthesis and Crystal Structure

A new compound, ammonium (18-crown-6)(triphenylphosphine oxide) perchlorate (I), is synthesized, and its crystal structure is studied using X-ray diffraction analysis (space group R3m, a = 14.432 Å, c = 14.034 Å, Z = 3, direct method, full-matrix least-squares method in the anisotropic approximation, R = 0.064 for 1945 independent reflections, CAD4 automated diffractometer, λMoKα radiation). In the structure, the NH ₄ ⁺ cation resides in the 18-crown-6 macrocycle cavity and is hydrogen-bonded with three symmetrically equivalent O atoms of the 18-crown-6 molecule and with the phosphoryl O atom of the Ph₃PO molecule. The P=O H-N and Cl atoms occupy the partial position 3m. The oxygen atoms of the ClO ₄ ^? anion are disordered over the 3m position.     

Bis[(1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane)-(isothiocyanato)potassium] [K2(NCS)2(C18H22O6)2]: Crystal and Molecular Structure

Complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with potassium thiocyanate, [K₂(NCS)₂L₂] (I) was synthesized and studied using X-ray diffraction analysis: space group P , a = 7.771 Å, b = 11.711 Å, c = 11.965 Å, = 72.22°, = 79.21°, = 89.07°, Z = 1. Structure I was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.040 for all 4370 independent reflections (CAD4 autodiffractometer, MoK ). Structure I contains [K(NCS)L] monomers of the host–guest type united into centrosymmetrical [K₂(NCS)₂L₂] dimers via two bridging OH groups (one group from two L podands). In the monomer, the L podand appears as though to envelope the octacoordinated K⁺ cation, whose the coordination polyhedron is a strongly distorted hexagonal bipyramid with all six oxygen atoms of the L podand in its base and the N atom of the SCN^– ligand and the O atom of one of OH group of the neighboring (in dimer) L podand at its axial vertices. Molecules of I in crystal are joined through the O–H···N hydrogen bonds to form broad infinite chains along the x-axis.     

Synthesis and Crystal Structure of (18-Crown-6)(nitrato)(triphenylphosphine oxide)potassium

A new complex (18-crown-6)(nitrato)(triphenylphosphine oxide)potassium (I) is synthesized, and its crystal structure is studied by X-ray diffraction analysis (space group R3m, a = 14.336 Å, c = 13.776 Å, Z = 3). The structure is solved by the direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.034 for 1122 independent reflections (CAD4 automated diffractometer, λ MoK_α radiation). Structure I contains a complex host-guest molecule [K(NO₃)(18-crown-6)(Ph₃PO)] with crystallographic symmetry 3m (three planes m contain three Ph rings of the Ph₃PO ligand and all O atoms of the crown ligand). The coordination polyhedron of the K⁺ cation is a distorted hexagonal bipyramid with all the six O atoms of the crown ligand in the base, the O atoms of the Ph₃PO ligand, and one (or two) O atoms of a disordered NO ₃ ^? ligand in the axial positions.     

Reaction of early transition metal complexes with macrocycles. II. Synthesis and structure of TiCl3(H2O) · 18-crown-6, a compound with a unique bidentate bonding mode for the 18-crown-6 molecule

18-crown-6 reacts with TiCl₃ in CH₂Cl₂ to form a complex in which the crown ether functions as a tridentate ligand. Addition of moist hexane affords a molecular complex in which the crown ether functions as a bidentate ligand. A water molecule is bonded directly to the titanium atom and is further hydrogen bonded to three of the oxygen atoms of the crown. The deep blue crystals of the CH₂Cl₂ adduct belong to the monoclinic space groupP2₁/n witha=13.481(8),b=8.021(5),c=21.425(9) Å, =97.32(5)°, and _calc = 1.51 g cm^–3 forZ=4. Refinement led to a conventionalR value of 0.040 based on 873 observed reflections. The Ti–O bond distances for the crown oxygen atoms are 2.123(8) and 2.154(9) Å, while the oxygen atom of the water molecule is bonded at 2.072(8) Å. The octahedral coordination sphere of the titanium atom is completed by the three chlorine atoms at distances of 2.340(5), 2.352(4), and 2.373(4) Å. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82034 (10 pages).     

Neutral molecule/crown ether interactions 5. Comparison of the C−H acidic interactions of nitromethane and acetonitrile with 18-crown-6 and dibenzo-18-crown-6. Crystal structures of dibenzo-18-crown-6·2 CH3NO2 and dibenzo-18-crown-6·2 CH3CN

Complete structural characterization of dibenzo-18-crown-6·2 CH₃NO₂ and dibenzo-18-crown-6·2 CH₃CN have been carried out, including location and refinement of the methyl hydrogen atoms. Dibenzo-18-crown-6·2 CH₃NO₂ is monoclinic,P2₁/c, with (at –150°C)a=9.573(2),b=14.636(2),c=33.471(7) Å, =93.77(2)°, andD _calc=1.37 g cm^–3 forZ=8. Interactions between the solvent methyl groups and the crown ethers and other solvent nitro groups associate the 1 : 2 complexes into polymeric chains alongb. The acetonitrile adduct exists as discreet 1 : 2 complexes in the solid state with C–H...O interactions exlusively to the ether. This complex is triclinic,P 1, with (at –150°C)a=9.458(6),b=9.570(5),c=14.404(5) Å, =73.18(4), =79.85(5), =66.82(6)°, andD _calc=1.28 g cm^–3 forZ=2. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82070 (22 pages).For part 4, see reference [1].     

Crystal Structure of 1,10-Diazonia-18-crown-6 Bis(hydrogen oxalate) and 1,10-Diazonia-18-crown-6 Oxalate Dihydrate

An X-ray diffraction study has been performed to study the crystal structure of 1,10-diazonia-18-crown-6 bis(hydrogen oxalate) [H₂DA18C6]²⁺·2C₂HO ₄ ^- (I) and 1,10-diazonia-18-crown-6 oxalate dihydrate [H₂DA18C6]²⁺·2C₂O ₄ ^- ·2H₂O (II). Crystals I are triclinic: space group , a = 7.825, b = 7.861, c = 9.349 , = 97.28, = 110.22, = 99.12°, Z = 1. Crystals II are monoclinic: space group P2 ₁ /n, a = 8.783, b = 10.640, c = 10.225 , = 97.04°, Z = 2. The structures of I and II were solved by direct methods and refined by the full-matrix least-squares procedure anisotropically to R = 0.036 (I) and 0.042 (II) for all 2206 (I) and 1990 (II) unique reflections measured (CAD-4 automatic diffractometer, CuK ). In the crystal structures, the ionic complexes (salts) I and II are not individual guest–host complex molecules but are parts of complex (infinite in two directions) three-dimensional layers of H-bonded molecular anions and DA18C6 dications (and water molecules in II). In structures I and II, the centrosymmetric DA18C6 dications have different conformations: two-angle in I and four-angle in II. The unusual four-angle conformation of the DA18C6 dication was found for the first time.     

Verfeinerung der Kristallstruktur von Kupfer(II)-hydroxichlorid,Cu(OH)Cl

The crystal structure of Cu(OH)Cl [a=5.555 (2) Å,b=6.671 (4) Å,c=6.127 (2) Å, =114.88 (3)°, space group P2_I/a,Z=4] was refined for 810 observed reflections with sin /0.80 Å^–1 toR=0.035. Crystals were synthesized under hydrothermal conditions. The copper atom is planar four coordinated by three oxygen atoms and one chlorine atom; two further chlorine atoms complete its coordination. The copper polyhedra share edges to build up sheets, which are connected by hydrogen bonds to the chlorine atoms of adjacent sheets.

     

Aminosulfuric acid: An excellent guest for crown ether complexation. Crystal structure of the 1∶1∶1 molecular complex between aminosulfuric acid,water and 18,19-benzo-1, 16-diaza-4,7,10,13-tetraoxacycloeicosa-17,20-dione

The twenty-membered macrocycle, 18,19-benzo-1, 16-diaza-4,7,10,13-tetraoxacycloeicosa-17,20-dione, C₁₈H₂₆N₂O₆ (1), aminosulfuric acid and water form a stoichiometric 111 inclusion compound. The crystal structure of [1·NH ₃ ⁺ SO ₃ ^– ]·H₂O has been determined by X-ray crystallography. The crystal is monoclinic, space groupP2₁/c, a=7.967(1),b=13.447(3),c=20.779(4) Å, =90.20(2) Å;Z=4. The finalR-value is 0.0434 for 4638 unique reflections withI>2(I). The structure consists of the 11 molecular complexes between the crown host and aminosulfuric acid revealing hydrogen bonding with the ligand ether and carbonyl oxygen atoms. The complexes are united in the layer-like structure by NH...O host-guest and NH...O=CF _obs,F _calc, tables of anisotropic displacement parameters, and fractional atomic coordinates of hydrogen atoms.     

The synthesis and structural analysis of Pt2Ru4(CO)18 and the products obtained from its reactions with 1, 2-bis(diphenylphosphino)ethane

From the reaction of Ru(CO)₅ and Pt(COD)₂, COD = 1, 5-cyclooctadiene, the new platinum-ruthenium heteronuclear cluster complex Pt₂Ru₄(CO)₁₈,1, was obtained in 60% yield.1 has a folded ladder-like structure with alternating pairs of ruthenium atoms and platinum atoms. The cluster of1 can be split to yield the known compound PtRu₂(CO)₈(²-dppe),2, (54% yield) by reaction with 1, 2-bis(diphenylphosphino)ethane, dppe, at 25°C. When1 was treated with excess dppe at 40°C, thebis-diphos compound3, PtRu₂(CO)₆(-²-dppe)₂ was obtained (39% yield). Under the similar reaction conditions,2 was converted to3 in 44% yield. All these complexes were characterized by single crystal X-ray diffraction analyses. Compounds2 and3 both contain a triangular cluster of one platinum and two ruthenium atoms, but in2 the bidentate ligand, dppe, chelates the platinum atom and in3 the two dppe ligands bridge the two Pt-Ru metal-metal bonds. Crystal data for1: space group C2/c,a=12.542(2)Å,b=15.350(4)Å,c=15.252(3)Å, =105.32(2)°,Z=4, 2192 reflections,R=0.025. For2: space group P2₁/c,a=14.351(2)Å,b=13.486(3)Å,c=19.218(3)Å, =108.48(1)°,Z=4, 3029 reflections,R=0.027. For3: space group P2₁/c,a=18.836(6)Å,b=15.559(5)Å,c=23.259(7)Å, =111.26(2)°,Z=4, 4204 reflections,R=0.038.