Crystal Structures of the 1,2-Dihydroquinazolinium-4-yl Pd(II) Complexes [PdI{C=N(Xy)CH(R)NHC6H4-2}(CNXy)2]OTf (R?=?Me, CH?=?CH2, C6H4Me-4) and of the 2-Iminoaryl Pd(II) Complex [PdI(C6H4{N=C(H)C6H4Me-4}-2)(2,2′-bipyridine)]

Abstract  

The crystal structures of trans-[PdI{C=N(Xy)CH(R)NHC₆H₄-2}(CNXy)₂]OTf (R = Me (1·CHCl₃) space group P-1, a = 8.7665(4) ?, b = 15.5346(8) ?, c = 16.2415(8) ?, α = 72.698(2)o, β = 78.310(3)o, γ = 88.310(2)o, CH = CH₂ (2·0.5Et₂O) space group P2₁/c, a = 15.7868(6) ?, b = 14.5066(6) ?, c = 18.5814(7) ?, β = 106.707(2)o, C₆H₄Me-4 (Tol) (3) space group P-1, a = 11.96075(5) ?, b = 12.9452(51) ?, c = 13.1263(5) ?, α = 93.306o, β = 95.822(2)o, γ = 94.572(2)o) have been measured. The structural data suggest the existence of some electron delocalization over the heterocyclic ring, the extension of which seems to depend on the R substituent. The complex [PdI{C₆H₄(N=CHTol)-2}(bpy)] (Tol = C₆H₄Me-4, bpy = 2,2′-bipyridine, 4) is the fourth imino-substituted aryl palladium complex. Complex 4 crystallizes in triclinic P-1 with a = 8.7873(5) ?, b = 8.8936(5) ?, c = 13.8375(8) ?, α = 90.116(2)o, β = 92.760(2)o, γ = 106.243(2)o.     

The Crystal Structures of Some 1-Aryl-5-methyl-1,2,3-triazole Derivatives

Abstract  The two 1-aryl-5-methyl-1,2,3-triazole derivatives were prepared by the 1-aryl-5-methyl-1,2,3-triazol-4-carboxylic acids 3. The yielded products 4a–b were confirmed by NMR, MS, IR spectra. We investigated the crystalline structure of compounds 4a and 4b. Compound 4a, C₉H₈BrN₃, Mr = 238.09, crystallizes in the monoclinic space group P2(1)/n with unit cell parameters a = 11.660(2), b = 7.668(2), c = 11.818(2) ?, α = 90.00, β = 116.01(3), γ = 90.00o. V = 949.6(3) ?³, Z = 4, Dx = 1.665 Mg m⁻³. The final R was 0.0477. Compound 4b, C₁₃H₁₁N₃, Mr = 209.25, crystallized in the orthorhombic space group Pbca with unit cell parameters a = 10.373(2) ?, b = 11.691(2) ?, c = 17.579(4) ?, α = 90.00o, β = 90.00o, γ = 90.00o, V = 2131.8(7) ?³, Z = 8, D _m = 1.304 Mg m⁻³. The final R was 0.0565. Index Abstract  The two 1-aryl-5-methyl-1,2,3-triazole derivatives were prepared by the 1-aryl-5-methyl-1,2,3-triazol-4-carboxylic acids 3. The yielded products 4a–b were confirmed by NMR, MS, IR spectra. We investigated the crystalline structure of compounds 4a and 4b. Compound 4a, C9H8BrN3, Mr = 238.09, crystallizes in the monoclinic space group P2(1)/n with unit cell parameters a = 11.660(2), b = 7.668(2), c = 11.818(2)  ?, α = 90.00, β = 116.01(3), γ =90.00o. V = 949.6(3) ?³, Z = 4, Dx = 1.665 Mg m⁻³. The final R was 0.0477. Compound 4b, C13H11N3, Mr = 209.25, crystallized in the orthorhombic space group Pbca with unit cell parameters a = 10.373(2) ?, b = 11.691(2) ?, c = 17.579(4) ?, α = 90.00o, β = 90.00o, γ = 90.00o, V = 2131.8(7) ?³, Z = 8, D _m = 1.304 Mg m⁻³. The final R was 0.0565.      

Histamine Molecule and Dianion Oxalate are Efficient Blocks for Building 2D Supramolecular Networks

Abstract  

One salt and two Cu(II) complexes (H₂hsm)(ox), 1, [Cu(hsm)(ox)], 2, and [Cu(hsm)(ox)H₂O], 3, have been synthesized and X-ray characterized (hsm is histamine and ox²⁻ is the oxalate dianion). Starting from the prochiral tetracoordinated complex 2, pentacoordinated complex 3 crystallizes as a racemic mixture of the enantiomeric Δ and Λ isomers, in space group P2₁/c. In all cases, the side chain of the hsm group is gauche, allowing the formation of strong hydrogen bonds in the salt 1, and to chelate the metal center in complexes 2 and 3. The combination hsm/ox seems to favor the formation of 2D supramolecular structures (planes or wavy planes), through efficient networks of N–H···O hydrogen bonds. Cell parameters: 1, P2₁/c, a = 6.260 (2) ?, b = 11.500 (4) ?, c = 12.525 (4) ?, β = 104.047 (17)o; 2, C2/c, a = 10.7966 (13) ?, b = 15.5622 (16) ?, c = 11.3996 (15) ?, β = 106.261 (11)o; 3, P2₁/c, a = 7.0627 (6) ?, b = 7.1323 (6) ?, c = 20.0296 (19) ?, β = 91.529 (7)o.     

Synthesis,Characterization and Crystal Structure of a Mononuclear Zinc(II) Complex Derived from 2-[(2-Propylaminoethylimino)methyl]phenol

Abstract  

A new zinc(II) complex, [Zn(C₁₂H₁₈N₂O)Cl₂]·CH₃CN, derived from the Schiff base ligand 2-[(2-propylaminoethylimino)methyl]phenol, has been synthesized and characterized by elemental analysis, IR spectra, and X-ray crystallography. The complex crystallizes in the orthorhombic space group Pbcn with unit cell dimensions a = 26.387(9) ?, b = 7.389(2) ?, c = 18.731(6) ?, V = 3,652(2) ?³, Z = 8, R ₁ = 0.0455 and wR ₂ = 0.1143. The asymmetric unit of the compound contains a mononuclear [Zn(C₁₂H₁₈N₂O)Cl₂] complex and an acetonitrile molecule linked together by an intermolecular N–H···N hydrogen bond. Crystal packing is stabilized by intermolecular N–H···O hydrogen bonds linking the molecules into chains along the b axis of the unit cell.     

Synthesis,Crystal Structure and Thermal Properties of <Emphasis Type="Italic">N</Emphasis>-Acetyl-3-(2-furyl)-5-ferrocenyl-2-pyrazoline and <Emphasis Type="Italic">N</Emphasis>-Acetyl-3-(2-thienyl)-5-ferrocenyl-2-pyrazoline

Abstract  

Two novel ferrocenyl substituted N-acetyl-2-pyrazolines, N-acetyl-3-(2-furyl)-5-ferrocenyl-2-pyrazoline (3) and N-acetyl-3-(2-thienyl)-5-ferrocenyl-2-pyrazoline (4), have been synthesized and characterized by FTIR, ¹H-NMR, ¹³C-NMR techniques, elemental analysis and X-ray structure analysis. Thermal properties of these compounds have been determined by TGA, DTA and DSC analysis. Compound 3 (C₁₉H₁₈N₂O₂Fe) crystallizes in the monoclinic space group P21/c and Z = 4, with a = 8.6970(4) ?, b = 18.4725(9) ?, c = 11.0041(5) ?, β = 110.942(3)°. Compound 4 (C₁₉H₁₈N₂OSFe) crystallizes in the orthorhombic space group Fdd2 and Z = 16, with a = 84.242(2) ?, b = 13.5416(5) ?, c = 5.9405(2) ?, β = 90°. In terms of crystal packing, each compound shows different molecular arrangement, which are stabilized by C–H···O intermolecular weak hydrogen bonds, and/or C–H···π interactions.     

Synthesis,Characterization and Crystal Structures of <Emphasis Type="Italic">N</Emphasis>′-(5-Bromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide in Unsolvated and Monohydrate Forms

Abstract  

A new hydrazone derivative, N′-(5-bromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide (BFBH), has been prepared and crystallized from absolute methanol and 95% ethanol, respectively, yielding unsolvated and monohydrate forms of the compound, viz. BFBH (1) and BFBH·H₂O (2). The two forms of the compound were characterized by elemental analysis, IR spectra, ¹HNMR spectra, and X-ray single crystal structural determination. The unsolvated form of the compound crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 6.879(1) ?, b = 28.911(2) ?, c = 8.724(1) ?, β = 127.685(2)o, V = 1373.1(3) Ǻ³, Z = 4, R ₁ = 0.0569, and wR ₂ = 0.1352. The monohydrate forms of the compound crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 14.873(3) ?, b = 7.265(1) ?, c = 13.043(2) ?, β = 96.281(2)o, V = 1400.9(4) Ǻ³, Z = 4, R ₁ = 0.0402, and wR ₂ = 0.0890. The two structures are similar to each other, except for the presence of a water molecule in (2).     

Synthesis,Crystal Structures,and Antibacterial Activity of Two Hydrazone Derivatives 3-Methoxy-<Emphasis Type="Italic">N</Emphasis>′-(3,5-Dibromo-2-Hydroxybenzylidene)Benzohydrazide Methanol Solvate and 3-Methoxy-<Emphasis Type="Italic">N</Emphasis>′-(2,4-Diclorobenzylidene)Benzohydrazide

Abstract  

Two new hydrazone compounds with the formulae C₁₅H₁₂Br₂N₂O₃·CH₃OH (1) and C₁₅H₁₂Cl₂N₂O₂ (2), were prepared and characterized by elemental analysis, IR spectra and single-crystal X-ray determination. Compound (1) crystallizes in the triclinic space group P-1 with unit cell dimensions a = 7.654(1) ?, b = 13.801(2) ?, c = 16.904(2) ?, α = 90.772(2)^o, β = 101.721(2)^o, γ = 95.891(2)^o, V = 1738.1(4) Ǻ³, Z = 4, R ₁ = 0.0495 and wR ₂ = 0.1161. Compound (2) crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.296(1) ?, b = 12.987(2) ?, c = 14.121(2) ?, α = 88.922(2)^o, β = 87.960(2)^o, γ = 84.130(2)^o, V = 1512.3(4) Ǻ³, Z = 4, R ₁ = 0.0526 and wR ₂ = 0.1220. The single crystal structure analysis indicates that compound (1) consists of two nearly coplanar hydrazone molecules and two methanol molecules which link to the hydrazone molecules through O–H···O hydrogen bonds, while compound (2) consists of two independent distorted hydrazone molecules. In the crystal structure of (1), adjacent two hydrazone molecules are linked with methanol molecules through intermolecular hydrogen bonds of O–H···O and N–H···O, forming a dimer. In the crystal structure of (2), molecules are linked through intermolecular N–H···O hydrogen bonds, forming chains running along the a axis.     

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.     

The Crystal Structure of 1-[2-(furan-2-yl)-6-methyl-1,2,3,4-tetrahydroquinolin-4-yl]Pyrrolidin-2-one

Abstract  

The title compound, C₁₈H₂₀N₂O₂, a potential pharmaceutical agent, crystallizes in the monoclinic P2₁/n space group with unit cell parameters a = 11.157 (7) ?, b = 8.776 (6) ?, c = 16.460 (11) ?, β = 103.08 (3)°. The tetrahydroquinoline ring system formed by the fusion of the benzene ring and the piperidine ring via two carbon atoms is coplanar, with the later adopting a sofa conformation. The pyrrolidine group in position 4 adopts an envelope conformation. Dimers related by inversion centers and linked by hydrogen bonds of the type N–H···O form cycles described by the graph set R₂²(16). Additionally, the dimers connect through weak hydrogen bonds of the type C–H···O with graph set C(10) to form chains extending along [001].     

Synthesis and Characterization of a Novel Unsymmetrical Tetradentate Schiff Base Complex of Zinc(II) Derived from N,N′-bis (5-Bromosalicylidene) 2,3-Diaminopyridine (H2L): Crystal Structure of [Zn(II)L]Pyridine

Abstract  

Yellow crystals of [Zn(N,N′-bis (5-bromosalicylidene) 2,3-diaminopyridine)] Pyridine, [Zn(C₁₉H₁₁Br₂N₃O₂)]C₅H₅N, have been obtained and characterized by elemental analysis, FT-IR, UV–Vis, ¹H NMR spectroscopy and MALDI-TOF mass spectrometry. The structure has been determined by single crystal X-ray crystallography. The complex crystallizes in the triclinic space group P-1 with two molecules in the asymmetric unit and with unit cell dimensions a = 8.0103(3) ?, b = 12.8340(5) ?, c = 22.3682(11) ?, α = 91.715(2)°, β = 93.918(2)°, γ = 103.708(2)°. V = 2226.30(16) ?³, Z = 4, R ₁ = 0.0780 and wR ₂ = 0.1192. X-ray structure determination revealed that the complex consists of a [Zn(C₁₉H₁₁Br₂N₃O₂)] moiety with a coordinated pyridine molecule on the metallic centre. The zinc atom adopts a distorted square pyramidal geometry as it is shown in the crystal structure.     

Unclassical Hydrogen Bonds of C–H⋯N and C–H⋯Cl in the Crystal Structures of 2-((<Emphasis Type="Italic">E</Emphasis>)-1,3-diarylallylidene)malononitriles

Abstract  

The 2-((E)-3-(2-nitrophenyl)-1-(4-methoxyphenyl)allylidene)malononitrile and 2-((E)-3-(2-chlorophenyl)-1-(4-bromophenyl)allylidene)malononitrile were synthesized and characterized by IR, ¹H NMR, and elemental analysis. The molecular structures were further confirmed by X-ray diffraction analysis. The former 1, C₁₉H₁₃N₃O₃, is triclinic, space group P−1, a = 7.3834(13), b = 10.901(3), c = 11.227(2) ?, α = 88.64(2), β = 71.596(14), γ = 78.186(18), Z = 2, V = 838.5(3) ?³. The unclassical hydrogen bond of C–H⋯N links the molecules forming polymers. The latter 2, C₃₆H₂₀Br₂Cl₂N₄, is orthorhombic, space group Pnma, a = 20.900 (4), b = 7.0710 (11), c = 10.9170 (18) ?, Z = 2, V = 1613.4(5) ?³. The same hydrogen bond of C–H⋯N and another type of C–H⋯Cl hydrogen bond link the adjacent molecules forming polymers along a axis.     

Crystal and Molecular Structures of Di-1-Adamantylthiophosphinic Chloride, <Emphasis Type="Italic">P</Emphasis>,<Emphasis Type="Italic">P</Emphasis>-Diphenyl-<Emphasis Type="Italic">N</Emphasis>-Benzyl Phosphinothioic- and Selenoic- Amides

Abstract  Synthesis and X-ray structural determination of three phosphorus compounds are reported. (3b) is monoclinic P2(1)/c with a = 11.852(1), b = 12.825(1), c = 12.445(1) ?, β = 103.693(1)o; (4a) and (4b) are monoclinic P2(1)/n with a = 12.1422(16), b = 9.0860(12), c = 14.845(2) ?, β = 96.498(3)o for (4a), and a = 12.2714(16), b = 9.2812(12), c = 14.800(2) ?, β = 97.176(2)o for (4b). They all exhibit distorted tetrahedral geometry about the P atom. Ph₂P(X)NHC₇H₇ (X=S (4a) and X=Se (4b)) show typical P–S and P–Se double bond distances and P–N single bonds, while P–S bond in 1-Ad₂P(S)Cl (3b) is comparable to P–S single bonded probably due to the largeness of 1-adamantyl groups. Graphical Abstract  Synthesis and X-ray structural determination of 1-Ad₂P(S)Cl (3b), Ph₂P(S)NHC₇H₇ (4a) and Ph₂P(Se)NHC₇H₇ (4b) are reported.      

Synthesis, Crystal Structures and Fluorescence Property of Bis(benzimidazol-2-yl)methane Dichloride

Abstract  

The title compound, a salt of C₁₅H₁₃N₄ ²⁺2Cl⁻, was synthesized and determined by X-ray crystallography. It crystallizes in the orthorhombic system, space group Pbcn, with lattice parameters a = 9.973(2) ?, b = 9.5012(19) ?, c = 15.574(3) ?, V = 1475.8(5) ?³, Z = 4, C₁₅H₁₃Cl₂N₄, Mr = 320.19, Dc = 1.441 g/cm³. In the crystal structure, the Cl⁻ anion interact with the same benzimidzaole through two kinds of hydrogen bonds forming a 1D hydrogen-bonded chain, two 1D hydrogen-bonded chain cross with each other and form 2D layer structure. The EA, UV, IR and TG-DTG were studied and the possible structures of the title compound were speculated. Moreover, the fluorescence of the title compound was studied. The results reveal that it can emit purple fluorescence in DMF solvent.     

Structural Studies of [Ru(1,8-naphthyridine)<Subscript>4</Subscript>]<Superscript>2+</Superscript> and [Ru(1,5-cyclooctadiene)(1,8-naphthyridine)<Subscript>2</Subscript>]<Superscript>2+</Superscript> as their Tetraphenylborate Salts

Abstract  

The previously reported [Ru(naph)₄]²⁺ complex (naph = 1,8-naphthyridine) has been prepared by a simplified route using [RuCl₂(1,5-COD)] _x (COD = cyclooctadiene) as starting material and isolated as its tetraphenylborate salt. The salt crystallizes in the monoclinic space group P2₁/n with a = 13.6531(3) ?, b = 12.5389(4) ?, c = 20.0349(5) ?, β = 96.5884(15)o, V = 3407.22(16) ?, D _calc = 1.300 at 150(1) K. The dication has crystallographically imposed inversion symmetry. Although the iron analogue has been found to have a coordination number of eight, the ruthenium complex is only six-coordinate, which is achieved by the presence of two monodentate and two bidentate 1,8-naphthyridine ligands. The observation of a higher coordination number for Fe(II) vs. Ru(II) can be explained by the high spin nature of the iron complex. A byproduct complex, [Ru(1,5-COD)(naph)₂][B(C₆H₅)₄]₂, could also be synthesized, isolated pure, and structurally characterized. The organometallic complex possesses an 18 electron configuration by virtue of the dicationic metal center being coordinated by the diene ligand and all four nitrogen lone pairs. This salt crystallizes in the triclinic space group \textP[`1] {\text{P}}\bar{1} with a = 12.9538(3) ?, b = 14.9485(3) ?, c = 17.4291(3) ?, α = 69.0649(11)o, β = 78.3211(9)o, γ = 78.5629(10)o, V = 3057.50(11) ?³, D _calc = 1.293 at 150(1) K.     

The molecular structures of three germacrolides related to parthenolide

The germacrolide-class sesquiterpene lactone, 1,10-epoxyparthenolide, C₁₅H₂₀O₄,1, crystallizes with two independent molecules in monoclinic space groupP2₁ witha=10.6845(5),b=9.0763(4),c=15.4326(7) ?, β=105.887(4)°,V=1439.4(3) ?³,Z=4.R=0.037 for 2425 observed data. Its 11βH, 13-dihydro-derivative 1,10-epoxydihydroparthenolide, C₁₅H₂₂O₄,2, crystallizes in orthorhombic space groupP2₁2₁2₁ witha=7.6414(10),b=12.559(2),c=14.6821(14) ?,V=1409.0(3) ?³ Z=4.R=0.031 for 1555 observed data. The corresponding unexposidized compound, 11βH,13-dihydrocostunolide, C₁₅H₂₂O₂,3, crystallizes with three independent molecules in orthorhombic space groupP2₁2₁2₁ witha=7.3576(5),b=23.505(3),c=24.185(2) ?,V=4182(1) ?³,Z=12.R=0.070 for 2767 observed data. In all, the 10-membered rings adopt approximate chair-chair conformations. In all, the double bonds or epoxidized double bonds are E, both methyl groups on the 10-ring are β, and the α-methylene-γ-lactone (or α-methyl-γ-lactone) istrans-fused at C6 and C7 with H6 β and H7 α. In the dihydro compounds, the H at C11 is β.     

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.     

Structural Studies of Coupling Products Formed Between (C6H5)CH=N(C6H5) and the M(C5H5)(6,6-dmch) Fragments (M?=?Ti, Zr; dmch?=?dimethylcyclohexadienyl)

Abstract  

The reactions of Ti(C₅H₅)(6,6-dmch)(PMe₃) and Zr(C₅H₅)(6,6-dmch)(PMe₃)₂ with two equivalents of C₆H₅C(H)=N(C₆H₅) have led to couplings of the imines to the 1,5 (terminal) positions of the 6,6-dmch ligands. In both cases the PMe₃ ligands are lost, and the metal complexes each attain 18 electron configurations via η⁵-(C₅H₅), η³-allyl, and bis(π-amide) coordination. The complexes each crystallize in the monoclinic space group P2₁/c. For the titanium complex, a = 10.4336(1) ?, b = 9.0407(1) ?, c = 32.5547(6) ?, β = 94.2939(5)°, V = 3062.17(7) ?³, D_calc = 1.264 at 200(1) K. For the zirconium complex, a = 13.8900(3) ?, b = 10.0873(2) ?, c = 22.4543(6) ?, β = 90.7638(7)°, V = 3145.85(12) ?³, D_calc = 1.322 at 150(1) K.     

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].     

Copper(II) and lead(II) complexes of 4,4′-bipyridine-<Emphasis Type="Italic">N,N</Emphasis>′-dioxide

Cu(II) and Pb(II) complexes of 4,4′-bipyridine-N,N′-dioxide have been prepared using a solvent-layering system. [Cu₂Cl₄(bpdo)₃(H₂O)₂] . 2(CH₃)₂SO (1) crystallises in P-1, a=8.731(2), b=8.943(2), c=14.408(3) ?, α=102.85(3), β=97.49(3), γ=109.77(3)°. The Cu(II) complex is a z-shaped discrete molecule with a DMSO molecule hydrogen bonded to the host through coordinated water molecule. Crystallisation of PbCl₂, PbBr₂ and PbI₂ with bpdo afforded isostructural 2D coordination polymers. [PbCl₂(bpdo)]_n is monoclinic, C2/c with a=16.3274(7), b=4.0708(1), c=18.6146(8) ?, β=93.73(1)°; [PbBr₂(bpdo)]_n is monoclinic, C2/c with a=16.403(3), b=4.2412(8), c=18.846(4) ?, β=92.59(3)° and [PbI₂(bpdo)]_n is monoclinic, C2/c with a=16.438(3), b=4.538(1), c=18.973(4) ?, β=91.04(3)°. The adjacent metal centres of these polymers are bridged by coordinated Cl⁻, Br⁻ or I⁻ anions as well as by bpdo ligands. These polymers possess no conventional hydrogen bonds.