Structures and Characterization of [Zn(n-chlorosalicylato)2(N-methylnicotinamide)2(H2O)2] (n?=?4 or 5) Ligand Isomers

Abstract  

Two ligand isomers [Zn{4-ClC₆H₃-2-(OH)COO}₂(Menia)₂(H₂O)₂] (I) and [Zn{5-ClC₆H₃-2-(OH)COO}₂(Menia)₂(H₂O)₂] (II) (Menia = N-methylnicotinamide) were prepared and characterized by elemental analysis, IR spectroscopy and thermal analysis. The X-ray crystal structures of complexes (I) and (II) were determined. Compound (I) crystallizes in the triclinic space group P[`1] P\bar{1} with a = 8.105(1) ?, b = 10.036(2) ?, c = 10.545(2) ?, α = 109.088(9)°, β = 91.416(8)°, γ = 102.757(9)°, V = 786.2(2) ?<sup>3</sup>, Z = 1. Compound (II) crystallizes in the triclinic space group P[`1] P\bar{1} . Its cell parameters are: a = 8.133(1) ?, b = 10.119(2) ?, c = 10.428(1) ?, α = 66.44(1)°, β = 74.32(1)°, γ = 80.16(1)°, V = 755.5(2) ?³, Z = 1. The molecular structure of both isomers is monomeric. Each Zn(II) atom is hexacoordinated by three pairs of unidentate ligands in trans-positions (ZnO₄N₂). The 5-Clsal complex is somewhat less distorted than 4-Clsal complex (Cl-sal = chlorosalicylate). The structural data are compared with those found in similar [Zn(RCOO)₂(NL)₂(H₂O)₂].     

Syntheses and Crystal Structures of Two New Cadmium(II) and Nickel(II) Complexes with 1,4-Phenylenediacetate and 2,2′-Bipyridyl-Like Ligands

Abstract  

Two new complexes, namely [Cd(PDA)_0.5(2,2′-bpy)Cl](H₂PDA) (1) and [Ni(PDA)(phen)(H₂O)]₂ (2) (H₂PDA = 1,4-phenylenediacetic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by elemental analysis, IR spectra and X-ray crystal diffraction. Single-crystal X-ray diffraction analysis shows that complex 1 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.760 (4) ?, b = 11.190 (5) ?, c = 13.917 (7) ?, α = 110.383 (5)°, β = 101.736 (5)°, γ = 100.612 (5)°, V = 1202.8 (10) ?³, Z = 2, R ₁ = 0.0314 and wR ₂ = 0.0898. Complex 2 crystallizes in the monoclinic space group P2(1)/n with unit cell dimensions a = 9.911 (3) ?, b = 17.924 (6) ?, c = 10.638 (4) ?, β = 94.998 (5)°, V = 1882.7 (11) ?³, Z = 2, R ₁ = 0.0397 and wR ₂ = 0.1150. In complex 1, Cd(II) ions are alternately bridged by PDA ligands and chloride ions into 1D chains and the PDA ligands display trans-configuration. Complex 2 is a dimer and two Ni(II) ions are linked by two PDA ligands with cis-configuration, resulting in a cyclic structure. In spite of these differences, both in complexes 1 and 2 there are π–π stacking interactions and hydrogen bonding to make them 3D supramolecular frameworks.     

Investigations of 2-Thiazoline-2-thiol as a Ligand: Synthesis and X-ray Structures of [Mn2(CO)7(μ-NS2C3H4)2] and [Mn(CO)3(PPh3)(κ2-NS2C3H4)]

Abstract  Treatment of Mn₂(CO)₁₀ with 2-thiazoline-2-thiol in the presence of Me₃NO at room temperature afforded the dimanganese complexes [Mn₂(CO)₇(μ-NS₂C₃H₄)₂] (1) and [Mn₂(CO)₆(μ-NS₂C₃H₄)₂] (2) in 51 and 34% yields, respectively. Compound 1 was quantitatively converted into 2 when reacted with one equiv of Me₃NO. Reaction of 1 with triphenylphosphine at room temperature furnished the mononuclear complex [Mn(CO)₃(PPh₃)(κ ²-NS₂C₃H₄)] (3) in 66% yield. All three new complexes have been characterized by elemental analyzes and spectroscopic data together with single crystal X-ray diffraction studies for 1 and 3. Compound 1 crystallizes in the orthorhombic space group Pbca with a = 12.4147(2), b = 16.2416(3), c = 19.0841(4) ?, β = 90°, Z = 8 and V = 3848.01(12) ?³ and 3 crystallizes in the monoclinic space group P 2₁/n with a = 10.41730(10), b = 14.7710(2), c = 14.9209(2) ?, β = 91.1760(10)°, Z = 4 and V = 2295.45(5) ?³. Graphical Abstract  Two new dimanganese complexes [Mn₂(CO)₇(μ-NS₂C₃H₄)₂] (1) and [Mn₂(CO)₆(μ-NS₂C₃H₄)₂] (2) were formed when [Mn₂(CO)₁₀] was treated with 2-thiazoline-2-thiol in the presence of Me₃NO. Compound 2 reacts with PPh₃ to give the monomeric complex [Mn(CO)₃(PPh₃ )(κ ²-NS₂C₃H₄)]. The structures of 1 and 3 were established by crystallography. Shishir Ghosh, Faruque Ahmed, Rafique Al-Mamun, Daniel T. Haworth, Sergey V. Lindeman, Tasneem A. Siddiquee, Dennis W. Bennett, Shariff E. Kabir Investigations of 2-thiazoline-2-thiol as a ligand: Synthesis and X-ray structures of [Mn₂(CO)₇(μ-NS₂C₃H₄)₂] and [Mn(CO)₃ (PPh3)(κ ²-NS₂C₃H₄)].      

Molecular Association of Almotriptan with Oxalate and Terephthalate Anions

Abstract  

Crystal structures of anti-migraine drug almotriptan were crystallized with oxalic acid (I) and with terephthalic acid (II) and their crystal structures and molecular associations were determined using X-ray diffraction methods. Crystals of both (I) and (II) are monoclinic, space group P2₁/c, with a = 5.6270(4) ?, b = 27.6419(19) ?, c = 13.6228(9) ?, β = 93.057(1)°, V = 2115.9(3) ?³, Z = 4 (I) and a = 13.3756(15) ?, b = 15.6065(17) ?, c = 10.7238(12) ?, β = 98.017(2)°, V = 2216.7(4) ?³, Z = 4 (II). In almotriptan oxalate {systematic name: N,N-dimethyl-2-[5-(pyrrolidin-1-ylsulfonyl-methyl)-1H-indol-3-yl]-ethanaminium semioxalate}, C₁₇H₂₆N₃O₂S⁺, C₂HO₄ ⁻, (I) and in almotriptan hemi terephthalate hydrate {systematic name: N,N-dimethyl-2-[5-(pyrrolidin-1-ylsulfonyl-methyl)-1H-indol-3-yl]-ethanaminium hemi terephthalate monohydrate}, C₁₇H₂₆N₃O₂S⁺, 0.5(C₈H₄O₄ ²⁻), H₂O, (II), both the almotriptan cations form a trimer with the corresponding anions via N–H···O hydrogen bonds. In (I), the oxalate salt is monoprotonated and in (II), the terephthalic acid is located across the inversion centre and exists as doubly protonated anion. In (I), the cation and anion are interlinked by the N–H···O and O–H···O hydrogen bonds into continuous two-dimensional layers generate an R₆⁶(34) hydrogen-bonded motif tetramers running parallel to the (0 0 1) plane. In (II), the cation and water form a centrosymmetric tetramer of R₄⁴(22) hydrogen-bonded motif via N–H···O and O–H···O hydrogen bonds and further cross-linked by centrosymmetric anions to form an infinite three-dimensional supramolecular hydrogen-bonded networks.     

Synthesis and Characterization of Some Transition Metal Complexes with Mixed Adenine and Acetylacetonate Ligands: Crystal Structures of Solvated Complex {[Cu(acac)<Subscript>2</Subscript>(adenine)]·EtOH} and {[Cu(acac)<Subscript>2</Subscript>(adenine)]·DMF·H<Subscript>2</Subscript>O}

Abstract  

Metal complexes of divalent copper (1–2), cobalt (3), and nickel (4) with mixed ligands acetylacetone (acac) and adenine were prepared and characterized by IR, mass spectra, elemental and thermal analysis. The X-ray crystal structures of {[Cu(acac)₂(adenine)]·EtOH} complex (1) and {[Cu(acac)₂(adenine)]·DMF·H₂O} (2) were determined. Compound (1) crystallizes in the triclinic space group P − 1 with a = 7.547(3) ?, b = 7.828(3) ?, c = 17.791(6) ?, α = 79.538(6)°, β = 82.240(7)°, γ = 86.010(6)°, V = 1023.1(6) ?³, and Z = 2. Complex (1) forms a hydrogen bonded 2:2 complex {[Cu(acac)₂(adenine)]₂:[EtOH]₂} arranged in bilayers. Complex (2) crystallizes in the triclinic space group P − 1 with a = 7.828(2) ?, b = 8.095(2) ?, c = 16.995(5) ?, α = 78.508(5)°, β = 84.949(5)°, γ = 89.285(5)°, V = 1051.2(5) ?³, and Z = 2. Complex (2) also forms bilayers with H-bonded DMF. Thermal analysis TG and DSC of the compounds (25–800 °C, under N₂) reveals the disproportionation of ligands with the associated heat.     

Sandwich-Type Manganese-Substituted Polyoxometalate, [(α-B-ZnW9O34)2W2Mn2(H2O)2]8?

Abstract  

The novel dimeric manganese-substituted polyoxotungstate Na₁₀[(α-B-ZnW₉O₃₄)₂W₂Mn₂(H₂O)₂](OH)₂·34H₂O (1) has been designed and synthesized from the hydrothermal reaction of Na₂WO₄·2H₂O, MnCl₂·4H₂O, and ZnCl₂ in a Teflon-lined stainless steel autoclave at 140°. X-ray diffraction analysis results reveal that compound (1) crystallizes in the monoclinic system, space group P2(1)/n, with a = 13.0901(3) ?, b = 17.8242(4) ?, c = 21.2401(5) ?, β = 93.6380(10)°, Z = 1, V = 4945.8(2) ?³, F(000) = 5244, Dc = 3.974 g/cm⁻³, μ(Mo-Kα) = 2.4037 cm⁻¹, λ(Mo-Kα) = 0.71073 ?. The structure was refined to R = 0.0631 and wR = 0.1532. The polyoxoanion of [(α-B-ZnW₉O₃₄)₂W₂Mn₂(H₂O)₂]⁸⁻ consist of two Keggin lacunary α-B-ZnW₉O₃₄ ¹²⁻ moieties linked via a rhomblike W₂Mn₂O₁₆ group leading to a sandwich-type structure.     

X-ray Structure of <Emphasis Type="Italic">mer</Emphasis>-[Mo(CO)<Subscript>3</Subscript>(PPh<Subscript>3</Subscript>)(<Emphasis Type="Italic">κ</Emphasis><Superscript>2</Superscript>-dppm)]

Abstract  

Treatment of [Mo(CO)₃(NCMe)₃] with bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh₃) at 50 °C afforded mer-[Mo(CO)₃(PPh₃)(κ ²-dppm)] (1) in 55% yield which has been characterized by single crystal X-ray diffraction studies and spectroscopic measurements. Compound 1 crystallizes in the triclinic space group P−1 with a = 10.3449(6), b = 11.1570(6), c = 17.8961(10) ?, β = 80.8400(10)°, Z = 2 and V = 1959.8(2) ?³.     

Self-Assembly of Two Isomorphous Thiocyanate Complexes of Co(II) and Ni(II) with 3-Hydroxypicolinamide

Abstract  

The synthesis, thermal and spectral characterization, and crystal structure of isomorphous thiocyanate cobalt(II) and nickel(II) complexes with 3-hydroxypicolinamide (3-OHpia), [M(C₆H₆N₂O₂)₂(NCS)₂]·2H₂O, are reported. The metal(II) ions are chelated by two cis-oriented 3-OHpia and two thiocyanate ligands in distorted octahedral geometry. The distortion within the coordination sphere is mainly imposed by formation of the chelate rings. The compounds crystallize in monoclinic space group P2/c with two symmetrically independent molecules and a = 14.4945(2) ?, b = 8.5906(1) ?, c = 16.3865(3) ?, β = 105.987(2)°, Z = 4 (1) and a = 14.4927(5) ?, b = 8.5912(3) ?, c = 16.2712(6) ?, β = 105.740(4)°, Z = 4 (2). Commonly observed supramolecular amide synthons are not robust enough to accommodate thiocyanate ions and H₂O molecules. But instead, neutral complexes are linked through hydrogen bonds leading to two different hydrogen bonding ribbon motifs involving amide moieties and H₂O molecules [C(8)R ₂²(12) along c axis] and amide moieties and thiocyanate ions [C(8)R ₂²(16) along b axis] for symmetrically related molecules labelled as 1 [Co1 (1) and Ni1 (2)] and 2 [Co2 (1) and Ni2 (2)], respectively.     

Reactivity of [Re2(CO)8(MeCN)2] With 1-vinylimidazole: X-ray Structures of [Re2(CO)8{η1-NC3H3N(CH=CH2)}2] and [ReCl2(CO)2{η1-NC3H3N(CH=CH2)}2]

Abstract  Treatment of [Re₂(CO)₈(MeCN)₂] with excess 1-vinylimidazole in refluxing benzene gives three new compounds [Re₂(CO)₉{η ¹-NC₃H₃N(CH=CH₂)}] (1), [Re₂(CO)₈{η ¹-NC₃H₃N(CH=CH₂)}₂] (2) and [ReCl₂(CO)₂{η ¹-NC₃H₃N(CH=CH₂)}₂] (3) in 11, 32 and 2% yields, respectively. The solid-state structures of complexes 2 and 3 have been determined by single crystal X-ray diffraction studies. Compound 2 crystallizes in the monoclinic space group C2/c, with lattice parameters a = 13.8378(5) ?, b = 11.8909(5) ?, c = 14.4591(6) ?, β = 116.6470(10)°, Z = 4 and V = 2131.99(15) ?³. Compound 3 crystallizes in the monoclinic space group C2/c, with lattice parameters a = 10.1028(3) ?, b = 13.5640(5) ?, c = 12.5398(4) ?, β = 109.637(2)°, Z = 4 and V = 1618.4(9) ?³. The disubstituted dinuclear compound 2 contains two 1-vinylimidazole ligands coordinated through the imino nitrogen atoms at the equatorial sites, whereas the mononuclear compound 3 contains two carbonyl ligands, two N coordinated η ¹-1-vinylimidazole ligands and two terminal Cl ligands. Graphical Abstract  Two dinuclear complesxes [Re₂(CO)₉{η ¹-NC₃H₃N(CH=CH₂)}] (1) and [Re₂(CO)₈{η ¹-NC₃H₃N(CH=CH₂)}₂] (2) and the mononuclear [ReCl₂(CO)₂{η ¹-NC₃H₃N(CH=CH₂)}₂] (3) were obtained from the reaction of [Re₂(CO)₈(MeCN)₂] with excess 1-vinylimidazole at 80 °C. The X-ray structrures of 2 and 3 are described.      

A Comparative Study of (tBu3Si)SiX2SiX2(SitBu3) (X?=?Cl, Br, I) Including the Result of the X-Ray Structure Analysis of (tBu3Si)SiI2SiI2(SitBu3)

Abstract  

The tetraiodotetrasilane (tBu₃Si)SiI₂SiI₂(SitBu₃) can be prepared from precursor (tBu₃Si)SiH₂SiH₂(SitBu₃). When (tBu₃Si)SiH₂SiH₂(SitBu₃) was treated with an excess of iodine at 120 °C, (tBu₃Si)SiI₂SiI₂(SitBu₃) was formed. X-ray quality crystals of (tBu₃Si)SiI₂SiI₂(SitBu₃) were grown from benzene at ambient temperature. The tetraiodotetrasilane (tBu₃Si)SiI₂SiI₂(SitBu₃) crystallizes in the monoclinic space group C2/c, a = 10.0110(10) ?, b = 13.9130(10) ?, c = 25.422(2) ?, β = 99.072(4)°, V = 3496.6(5) ?³, Z = 4, d _calcd = 1.829 g cm³; R ₁ = 0.0844, wR ₂ = 0.1854 for 3,017 reflections with I > 2σ(I). X-ray-crystallographic data show that the bromo and iodo derivatives (tBu₃Si)SiX₂SiX₂(SitBu₃) (X = Br, I) are isomorphous. The solid-state structure of (tBu₃Si)SiI₂SiI₂(SitBu₃) as well as those of (tBu₃Si)SiX₂SiX₂(SitBu₃) (X = Cl, Br) reveals a staggered conformation which adopts a trans-orientation of the supersilyl substituent. Unequal dihedral angles as found in (tBu₃Si)SiX₂SiX₂(SitBu₃) (X = Cl, Br, I) indicate that these compounds are sterically overcrowded.     

The Synthesis and Crystal Structure Determination of Phenyl 2-(3,4-dihydro-1(2<Emphasis Type="Italic">H</Emphasis>)naphthalenylidine)hydrazinecarboxylate and Phenyl (2,4-dichlorophenyl-methylene)hydrazinecarboxylate

Abstract  

(E)-Phenyl 2-(3,4-dihydro-1(2H)-naphthalenylidine)hydrazinecarboxylate and (E)-phenyl (2,4-dichlorophenylmethylene)hydrazinecarboxylate were prepared by the condensation of 1-tetralone or 2,4-dichlorobenzaldehyde with phenyl hydrazinecarboxylate. Crystals of C₁₇H₁₆N₂O₂ 3 are monoclinic, C2/c, a = 17.763(4) ?, b = 8.353(2) ?, c = 40.233(8) ?, Z = 16, V = 5,839(2) ?³, R ₁ = 0.0448 and wR ₂ = 0.1104 for reflections with I > 2σ(I). Crystals of C₁₄H₁₀N₂O₂Cl₂ 5 are orthorhombic, P2₁2₁2₁, a = 8.288(3) ?, b = 14.082(2) ?, c = 23.788(5) ?, Z = 8, V = 2,777(1) ?³, R ₁ = 0.0815 and wR ₂ = 0.2006 for reflections with I > 2σ(I). The molecular packing in the crystal for both compounds is the result of N–H···O hydrogen bonding.     

Synthesis and Crystal Structures of pH-Dependent Ni(II) Coordination Polymers with 3-Pyrid-3-ylbenzoic Acid

Abstract  

Two pyridinecarboxylato-bridged coordination polymers[Ni(pbc)₂(H₂O)₂]_n(1) and {[Ni(pbc) ₂ (H₂O)]·H₂O}_n (2)(Hpbc = 3-Pyrid-3-ylbenzoic acid) have been synthesized by the hydrothermal method and characterized by elemental analysis, IR spectrum and single crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group P2₁/c with a = 9.519(5) ?, b = 9.417(5) ?, c = 11.701?, β = 98.086(5)°, V = 1038.5(9) ?³, Z = 2. Compound 2 crystallizes in monoclinic, space group P2₁/c with a = 10.490(2) ?, b = 12.920(3) ?, c = 16.074?, β = 95.97(3)°, V = 2166.7(8) ?³, Z = 4. X-ray diffraction analysis reveals that all pbc⁻ ligands act as diconnectors to link two Ni(II) centers and adopt one coordination mode: μ₂−N, O in compound 1 and the ligands adopt two coordination modes: μ ₂ −N, O and μ ₃ − N, O, O in compound 2.     

Synthesis and Structural Characterization of [2-(2-1H-Imidazoly)-1H-imidazolium nitrate] and [2-(2-1H-Imidazoly)-2H-imidazolium phthalyl glycinate] Based on the 2,2′-bi-1H-Imidazole Molecule

Abstract  

Two new compounds (H₃biim)(NO₃)(1) and (H₄biim)(phthgly)₂ (2) (H₂biim=biimidazole; Hphthgly=N-phthaloylglycine) have been synthesized and characterized by luminescence and single crystal X-ray diffraction study. Compound 1 crystallizes in the monoclinic space group C2/c, where a = 14.8078(15), b = 5.9233(6), c = 20.028(2) ?, β = 92.7910(10)°, V = 1754.6(3) ?³ and Z = 8. Compound 2 crystallizes in the monoclinic space group P2(1)/n, where a = 15.3775(14), b = 5.3200(6), c = 6.4689(18)?, β = 115.418(2)° V = 1216.9(2)?³ and Z = 4. In 1, the N–H groups of H₃biim⁺ and the oxygen atoms of NO₃ ⁻ are linked by hydrogen bonds leading to H₃biim⁺(N,N)–R₂²(10) and N–H···O interactions forming infinite 1D helical chains along the b-axis. Compound 2 consists of a planar diprotonated biimidazole moiety and two phthgly anions which connect to the dication by hydrogen bonds phthgly⁻(O,O)–R₂²(9).     

Synthesis and Crystal Structure of the Coordination Polymer [Cu(ppca′)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)(HgI<Subscript>2</Subscript>)](H<Subscript>2</Subscript>O) (ppca′ = 3,4′-bipyridine-6-carboxylic acid)

Abstract  

The coordination complex Cu(ppca′)₂(H₂O)₂ (1) was synthesized hydrothermally using the ligand 3,4′-bipyridine-6-carboxylic acid (ppca′). Complex 1 consists of pseudo-octahedral copper (II) units hydrogen bonded into a three-dimensional network that crystallizes in the monoclinic P2₁/n space group. In complex 1, a = 5.3429(4) ?, b = 29.343(2) ?, c = 6.7940(5) ?, and β = 110.635(2)°.     

Syntheses and Crystal Structures of Two 2-Aminoisoflavones

Abstract  

2-Amino-7,4′-dimethoxyisoflavone (I), C₁₇H₁₅NO₄ and 2-amino-7-methoxy-4′-hydroxyisoflavone (II), C₁₆H₁₃NO₄ were synthesized and their crystal structures were determined by single-crystal X-ray diffraction. They all crystallize in the monoclinic crystal system, space group P21/c. The cell dimensions of I are a = 15.6673(17) ?, b = 7.3998(8) ?, c = 13.2919(14) ?, β = 111.4460(10)°, D _c = 1.377 mg/mm³, V = 1,434.3(3) A³, Z = 4 and those of II are a = 10.990(7) ?, b = 11.879(7) ?, c = 10.422(6) ?, β = 96.904(11)°, D _c = 1.393 mg/mm³, V = 1,350.8(14) A³, Z = 4. A combination of F-type and T-type aromatic–aromatic interaction and hydrogen bonding links the molecules of I into a tri-dimensional framework structure. In the crystal structure of II, paired tri-centered hydrogen bond generates a R₄²(21) ring and the R₄²(21) rings link the molecules into a sheet.     

Crystal Structures of Two Aromatic Zinc(II) Carboxylates: [Zn(4-Chlorosalicylato)2(H2O)4]·2theophylline·(H2O)2 and Unique [Zn(5-Chlorosalicylato)2(isonicotinamide)2(H2O)]

Abstract  

The crystal structures of two zinc(II) 4-chloro- and 5-chlorosalicylate complexes, [Zn(4-ClC₆H₃-2-(OH)COO)₂(H₂O)₄]·2tph·(H₂O)₂ (I) and [Zn(5-ClC₆H₃-2-(OH)COO)₂(ina)₂(H₂O)] (II), where tph is theophylline and ina is isonicotinamide, have been determined using X-ray diffraction methods. Crystals of both (I) and (II) are triclinic, space group P-1, with Z = 1 in a cell with a = 7.2220(3), b = 8.59700(10), c = 16.0210(5) ?, α = 75.990(2), β = 83.959(2), γ = 68.455(2)°, V = 897.54(5) ?³ (I) and with Z = 2 in a cell with a = 11.4148(11), b = 11.5327(10), c = 12.0685(13) ?, α = 63.458(6), β = 87.547(8), γ = 89.387(7)°, V = 1419.9(2) ?³ (II). The coordination environment of the zinc(II) atom of compound (I) consists of two unidentate carboxylate oxygen atoms and four oxygen atoms of aqua ligands, forming a distorted octahedral configuration. Two theophylline molecules and the remaining water molecules are bound only by hydrogen bonds. The Zn atom of compound (II) is pentacoordinated with two unidentate carboxylate oxygen atoms, two pyridine nitrogen atoms of isonicotinamide ligands, and the oxygen atom of the aqua ligand, forming a distorted configuration between square pyramid and trigonal bipyramid. In both complexes intramolecular O–H···O hydrogen-bonding interactions are present. In the crystal structures, molecules are linked by intermolecular O–H···O and N–H···O hydrogen bonds. The structures are analyzed and compared to the similar Zn(II) complexes, with the chromophores ZnO₆ and ZnO₃N₂.     

Synthesis,Structure and Reactivity of Electron Deficient Triosmium Cluster Bearing 2,6-Dimethylbenzothiazolide Ligand

Abstract  

Reaction of [Os₃(CO)₁₀(NCMe)₂] with 2,6-dimethylbenzothiazole at room temperature affords [Os₃(CO)₁₀(μ-H){μ-η ²-C₇H₂NS(Me)₂}] (1) in 45% yield. Decarbonylation of 1 in refluxing toluene furnishes the electron-deficient cluster [Os₃(CO)₉(μ-H){μ ₃-η ²-C₇H₂NS(Me)₂}] (2) in almost quantitative yield. Treatment of 2 with PPh₃ at 40 °C gives the addition product [Os₃(CO)₉(PPh₃)(μ-H){μ-η ²-C₇H₂NS(Me)₂}] (3) in 85% in which the PPh₃ ligand is coordinated to the rear osmium atom. A similar treatment of 2 with P(OMe)₃ gives [Os₃(CO)₉{P(OMe)₃}(μ-H){μ-η ²-C₇H₂NS(Me)₂}] (4) in 60% yield with P(OMe)₃ ligand also coordinated to the rear metal. Compounds 3 and 4 differ by the disposition of the hydride ligands. In compound 4 both the hydride and the heterocyclic ligands simultaneously bridge the same metal–metal edge whereas they bridge different metal–metal edges in 3. Compounds 1–4 have been characterized by a combination of elemental analysis, infrared, NMR and mass spectral data together with single crystal X-ray diffraction studies for 3. Compound 3 crystallizes in the monoclinic space group P2₁/n with a = 9.2659(10), b = 23.643(2), c = 16.382(3) Å, β = 91.324(12)°, Z = 4 and V = 3,587.8(8) Å³.     

Molecular Structure of an Unexpected Binuclear Salicylaldimine Semicarbazone Palladium(II) Complex

Abstract  

Reaction of a salicylaldehyde semicarbazone ligand with PdCl₂(PPh₃)₂ yields an unexpected binuclear Pd(II) complex, 2. The complex crystallizes in a triclinic system with a P-1 space group, with unit cell parameters a = 14.0283(3) ?, b = 15.2603(3) ?, c = 18.7142(3) ?, α = 66.662(10)°, β = 86.162(10)°, γ = 76.265(10)°, Z = 2. The semicarbazone ligand acts as a tridentate chelating donor to one palladium metal centre, forming a five- and six- membered ring, and a monodentate donor to the second palladium centre. There are four molecules of solvent per complex molecule in the asymmetric unit. Each metal centre is contained within a slightly distorted square-planar environment.     

Metal Ion Interactions with Pyridinecarboxylates in Tripodal tris(2-Aminoethyl)amine Ligand System: Crystal Structures of [Ni(tren)(pic)]2(ClO4)2·CH3OH and [Co(tren)(dipic)]ClO4·CH3OH

Abstract  

Two new complexes [Ni(tren)(pic)]₂(ClO₄)₂·CH₃OH (1) and [Co(tren)(dipic)]ClO₄·CH₃OH (2), (tren is tris(2-aminoethyl)amine, pic is the anion of picolinic acid, dipic is the dianion of 2,6-pyridinedicarboxylic acid) have been synthesized and structurally characterized. X-ray analysis indicates that the two complexes are mononuclear with tren acting as a quadridentate ligand. In complex 1, the nickel(II) ion is further coordinated with picolinate in μ₂-N, O bidentate chelating mode. In complex 2, the cobalt(III) ion is coordinated with the pyridine nitrogen and one carboxylic oxygen of 2,6-pyridinedicarboxylate in μ₂-N, O chelating form. The metal atoms in both cases have distorted octahedral geometry. Crystal data: [Ni(tren)(pic)]₂(ClO₄)₂·CH₃OH (1), Mr = 869.03, monoclinic, C2/c, a = 26.354(5) ?, b = 10.407(2) ?, c = 25.839(5) ?, β = 96.24(3)°, Z = 8, V = 7045(2) ?³, R ₁ = 0.0418, wR ₂ = 0.1063 [I > 2σ(I)]; [Co(tren)(dipic)]ClO₄·CH₃OH (2), Mr = 501.77, Triclinic, P-1, a = 8.3667(2) ?, b = 10.4434(2) ?, c = 11.9431(16) ?, α = 73.9590(10)°, β = 88.0240(10)°, γ = 75.5890°, Z = 2, V = 969.97(4) ?³, R ₁ = 0.0408, wR ₂ = 0.1063 [I > 2σ(I)].     

Diphosphine ligand substitution in H4Ru4(CO)12: X-ray diffraction structures and reactivity studies of the cluster compounds H4Ru4(CO)10(P–P) [where P–P–(Z)–Ph2PCH–CHPPh2, bpcd]

The tetraruthenium cluster H₄Ru₄(CO)₁₂ (1) has been studied for its reactivity with the unsaturated diphosphine ligands (Z)–Ph₂PCH–CHPPh₂ and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) under thermal, near-UV photolysis, and Me₃NO-assisted activation. All three cluster activation methods promote loss of CO and furnish the anticipated substitution products H₄Ru₄(CO)₁₀[(Z)–Ph₂PCH–CHPPh₂] (2) and H₄Ru₄(CO)₁₀(bpcd) (3) that possess a chelating diphosphine ligand. Clusters 2 and 3 have been characterized in solution by IR and NMR spectroscopies, and these data are discussed with respect to the crystallographically determined structure for both new cluster compounds. The ³¹P NMR spectral data and the solid-state structures confirm the presence of a chelating diphosphine ligand in clusters 2 and 3. Cluster 2 crystallizes in the monoclinic space P2₁/c, a=11.768(6) ?, b=18.521(9) ?, c=20.48(1) ?, β=102.291(8)°, V=4361(4) A³, Z=4, and d _calc=1.726 Mg/m³; R=0.0225, R _w=0.0491 for 6798 reflections with I > 2σ(I). The four bridging hydrides were located in H₄Ru₄(CO)₁₀[(Z)–Ph₂PCH–CHPPh₂] and their adopted positions are discussed relative to the solution ¹H NMR spectrum. H₄Ru₄(CO)₁₀(bpcd) crystallizes in the orthorhombic space Pbca, a=19.072(3) ?, b=20.169(3) ?, c=22.774(3) ?, V=8760(2) A³, Z=8, and d _calc=1.870 Mg/m³; R=0.0428, R _w=0.0896 for 10296 reflections with I > 2σ(I). Sealed NMR tubes containing clusters 2 and 3 were found to be exceeding stable towards near-UV light and temperatures up to ca. 125 °C. The surprisingly robust behavior of 2 and 3 is contrasted with the related cluster Ru₃(CO)₁₀(bpcd) that undergoes fragmentation to the donor-acceptor compound Ru₂(CO)₆(bpcd) and the phosphido-bridged compound Ru₂(CO)₆(μ–PPh₂)[μ–C–C(PPh₂)C(O)CH₂C(O)] under mild conditions. The electrochemical properties of each substituted cluster have been investigated by cyclic voltammetry, and our findings are discussed with respect to the reported electrochemical data on the parent cluster H₄Ru₄(CO)₁₂.