Cyclic Bidentate Research Articles

A novel bidentate diamide ligand DODQ for the separation of uranium and rare earth ions in nitric acid medium

High efficiency extractants play a necessary role in the selective removal of uranium from rare earth minerals. In this paper, a novel cyclic bidentate diamine extractant, 1, 4-dioctyl-1, 4-dihydroquinoxaline-2, 3-dione (DODQ), was synthesized, and the complexation and extraction of UO22+ in nitric acid medium were systematically studied. The results indicate that DODQ exhibits a unique combination of properties in removing UO22+, with an extraction capacity 132 times higher than that of DODPhOA (acyclic structure). Extraction isotherm experiments and slope analyses illustrate the formation of a 1:1 DODQ/UO22+ regime during the extraction process. Electrospray mass spectrometry, fluorescence spectroscopy, and X-ray crystal diffraction analyses further corroborated its stoichiometric properties. In addition, DODQ can remove UO22+ from rare earth solutions containing UO22+ with high selectivity. This study provides an alternative method to separate uranium from the leaching solution of rare earth ore and has a new understanding of the coordination and complexing behavior of UO22+ with bidentate oxygen-containing ligands.

Platinum(II) complex with 4-nitro-N-(pyridin-2-ylmethylidene)aniline: synthesis, characterization, crystal structure and antioxidant activity.

A novel complex has been prepared using the (E)-4-nitro-N-(pyridin-2-ylmethylidene)aniline bidentate Schiff base ligand and PtCl2, namely, dichlorido[(E)-4-nitro-N-(pyridin-2-ylmethylidene)aniline-κ2N,N']platinum(II) acetonitrile hemisolvate, [PtCl2(C12H9N3O2)]·0.5CH3CN, 1. According to the X-ray measurements of the crystal structure, the PtII ion adopts a PtCl2N2 square-planar coordination. The coordination of the Schiff base ligand to the PtII ion occurs in a cyclic bidentate fashion, as a result of which a five-membered metallacycle is formed. Furthermore, in the structure of 1, the neutral molecules form a one-dimensional chain structure through C-H...Cl and C-H...O hydrogen bonds. The characterization of the complex was performed via single-crystal X-ray diffraction, IR spectroscopy and elemental analysis, and the antioxidant activity of the complex was evaluated using spectrophotometry by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method.

Synthesis, spectroscopic studies and inhibitory activity against bactria and fungi of acyclic and macrocyclic transition metal complexes containing a triamine coumarine Schiff base ligand

Two series of new mono and binuclear complexes with a Schiff base ligand derived from the condensation of 3-acetylcoumarine and diethylenetriamine, in the molar ratio 2:1 have been prepared. The ligand was characterized by elemental analysis, IR, UV–visible, 1H-NMR and mass spectra. The reaction of the Schiff base ligand with cobalt(II), nickel(II), copper(II), zinc(II) and oxovanadium(IV) lead to mono or binuclear species of cyclic or macrocyclic complexes, depending on the mole ratio of metal to ligand and as well as on the method of preparation. The Schiff base ligand behaves as a cyclic bidentate, tetradendate or pentaentadentae ligand. The formation of macrocyclic complexes depends significantly on the dimension of the internal cavity, the rigidity of the macrocycles, the nature of its donor atoms and on the complexing properties of the anion involved in the coordination. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either square pyramidal or octahedral for acyclic or macro-cyclic complexes. The structures are consistent with the IR, UV–visible, ESR, 1H-NMR, mass spectra as well as conductivity and magnetic moment measurements. The Schiff base ligand and its metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

Réparation de l’aile narinaire par lambeau de transposition horizontale

Two series of new mono and binuclear complexes with a Schiff base ligand derived from the condensation of 3-acetylcoumarine and diethylenetriamine, in the molar ratio 2:1 have been prepared. The ligand was characterized by elemental analysis, IR, UV–visible, 1H-NMR and mass spectra. The reaction of the Schiff base ligand with cobalt(II), nickel(II), copper(II), zinc(II) and oxovanadium(IV) lead to mono or binuclear species of cyclic or macrocyclic complexes, depending on the mole ratio of metal to ligand and as well as on the method of preparation. The Schiff base ligand behaves as a cyclic bidentate, tetradendate or pentaentadentae ligand. The formation of macrocyclic complexes depends significantly on the dimension of the internal cavity, the rigidity of the macrocycles, the nature of its donor atoms and on the complexing properties of the anion involved in the coordination. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either square pyramidal or octahedral for acyclic or macro-cyclic complexes. The structures are consistent with the IR, UV–visible, ESR, 1H-NMR, mass spectra as well as conductivity and magnetic moment measurements. The Schiff base ligand and its metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

Pd(II) and Pt(II) complexes of cyclic bidentate (S)PNP(S) ligands: Synthesis, structure and catalytic activity in the Suzuki reaction

The synthetic approach to the novel cyclic (S)PNP(S) ligands ▪ (5a–c, R=EtO, Me, Ph), i.e. 1-thiophosphoryl-2-thioxo-1,2-azaphospholanes having different surrounding at the exocyclic phosphorus atom, has been developed. Compounds bearing two asymmetric phosphorus atoms were obtained as individual (R∗,R∗)- and (R∗,S∗)-diastereomers. Reacting with (PhCN)2MCl2 (M=Pd, Pt) in MeCN under ambient conditions the ligands readily form complexes MLCl2 [6a–c (M=Pd), 7b (M=Pt)] via bidentate chelating coordination mode. The structures and stereochemistry both of the ligands and their complexes were confirmed by IR, multinuclear NMR and X-ray diffraction study. The palladium complexes demonstrated high activity as precatalysts for the Suzuki cross-coupling reaction, which was found to increase in the series 6a<6b<6c.

A Theoretical Study on the Alkylation of the Ambident Enolate from a Methyl Glycinate Schiff Base

The alkylation of the ambident enolates of a methyl glycinate Schiff base with ethyl chloride was studied at B3LYP and MP2 levels with basis set. The free (E)-enolates and (Z)-enolate are similar in energy and geometry. The transition states for the alkylation of the free (E)/(Z)-enolate with ethyl chloride have similar energy barriers of ~13 kcal/mol. However, with a lithium ion, the (E)-enolate behaves as an ambident enolate and makes a cyclic lithium-complex in bidentate pattern which is more stable by 11-23 kcal/mol than the (Z)-enolate-lithium complexes. And the TS for the alkylation of (E)-enolate-lithium complex coordinated with one methyl ether is lower in energy than those from (Z)-enolate-lithium complexes by 4.3-7.3 kcal/mol. Further solvation model (SCRF-CPCM) and reaction coordinate (IRC) were studied. This theoretical study suggests that the alkylation of ambident enolates proceeds with stable cyclic bidentate complexes in the presence of metal ion and solvent.

Unexpected Reactivity and Coordination in Gallium(III) and Indium(III) Chloride Complexes With Geometrically Constrained Thio- and Selenoether Ligands

Reaction of GaCl(3) with 1 mol equiv of [14]aneS(4) in anhydrous CH(2)Cl(2) gives the exocyclic chain polymer [GaCl(3)([14]aneS(4))] (1) whose structure confirms trigonal bipyramidal coordination at Ga with a planar GaCl(3) unit. In contrast, using [16]aneS(4) and GaCl(3) or [16]aneSe(4) and MCl(3) (M = Ga or In) in either a 1:1 or a 1:2 molar ratio produces the anion-cation complexes [GaCl(2)([16]aneS(4))][GaCl(4)] (2) and [MCl(2)([16]aneSe(4))][MCl(4)] (M = Ga, 3 and M = In, 4) containing trans-octahedral cations with endocyclic macrocycle coordination. The ligand-bridged dimer [(GaCl(3))(2){o-C(6)H(4)(SMe)(2)}] (5) is formed from a 2:1 mol ratio of the constituents and contains distorted tetrahedral Ga(III). This complex is unusually reactive toward CH(2)Cl(2), which is activated toward nucleophilic attack by polarization with GaCl(3), producing the bis-sulfonium species [o-C(6)H(4)(SMeCH(2)Cl)(2)][GaCl(4)](2) (6), confirmed from a crystal structure. In contrast, the xylyl-based dithioether gives the stable [(GaCl(3))(2){o-C(6)H(4)(CH(2)SEt)(2)}] (8). However, replacing GaCl(3) with InCl(3) with o-C(6)H(4)(CH(2)SEt)(2) preferentially forms the 4:3 In:L complex [(InCl(3))(4){o-C(6)H(4)(CH(2)SEt)(2)}(3)] (9) containing discrete tetranuclear moieties in which the central In atom is octahedrally coordinated to six bridging Cl's, while the three In atoms on the edges have two bridging Cl's, two terminal Cl's, and two mutually trans S-donor atoms from different dithioether ligands. GaCl(3) also reacts with the cyclic bidentate [8]aneSe(2) to form a colorless, extremely air-sensitive adduct formulated as [(GaCl(3))(2)([8]aneSe(2))] (10), while InCl(3) gives [InCl(3)([8]aneSe(2))] (14). Very surprisingly, 10 reacts rapidly with O(2) gas to give initially the red [{[8]aneSe(2)}(2)][GaCl(4)](2) (11) and subsequently the yellow [{[8]aneSe(2)}Cl][GaCl(4)] (12). The crystal structure of the former confirms a dimeric [{[8]aneSe(2)}(2)](2+) dication, derived from coupling of two mono-oxidized {[8]aneE(2)}(+•) cation radicals to form an Se-Se bond linking the rings and weaker transannular 1,5-Se···Se interactions across both rings. The latter (yellow) product corresponds to discrete doubly oxidized {[8]aneSe(2)}(2+) cations (with a primary Se-Se bond across the 1,5-positions of the ring) with a Cl(-) bonded to one Se. Tetrahedral [GaCl(4)](-) anions provide charge balance in each case. These oxidation reactions are clearly promoted by the Ga(III) since [8]aneSe(2) itself does not oxidize in air. The new complexes have been characterized in the solid state by IR and Raman spectroscopy, microanalysis, and X-ray crystallography where possible. Where solubility permits, the solution characteristics have been probed by (1)H, (77)Se{(1)H}, and (71)Ga NMR spectroscopic studies.

Phenol Nitration Induced by an {Fe(NO)2}10 Dinitrosyl Iron Complex

Cellular dinitrosyl iron complexes (DNICs) have long been considered NO carriers. Although other physiological roles of DNICs have been postulated, their chemical functionality outside of NO transfer has not been demonstrated thus far. Here we report the unprecedented dioxygen reactivity of a N-bound {Fe(NO)(2)}(10) DNIC, [Fe(TMEDA)(NO)(2)] (1). In the presence of O(2), 1 becomes a nitrating agent that converts 2,4,-di-tert-butylphenol to 2,4-di-tert-butyl-6-nitrophenol via formation of a putative iron-peroxynitrite [Fe(TMEDA)(NO)(ONOO)] (2) that is stable below -80 °C. Iron K-edge X-ray absorption spectroscopy on 2 supports a five-coordinated metal center with a bound peroxynitrite in a cyclic bidentate fashion. The peroxynitrite ligand of 2 readily decays at increased temperature or under illumination. These results suggest that DNICs could have multiple physiological or deleterious roles, including that of cellular nitrating agents.

ChemInform Abstract: Synthesis and Spectral Characterization of Medium-Ring Distannacycloalkanes and Their Lewis Acid Derivatives.

Abstract A study of the syntheses and some properties of several methyl substituted acyclic and cyclic bidentate organotin Lewis acids has been carried out. Of particular interest were cyclic species with 7-, 8-, 9- and 10-membered rings. The distannaalkanes and distannacycloalkanes were converted to the chlorides by chlorodemethylation with tin chlorides or mercuric chloride; this reaction was accompanied by ring cleavage in some cases. Chlorides, in turn, were readily converted to the methanesulfonates and trifluoromethanesulfonates. 1 H, 13 C and 119 Sn NMR and IR spectral data were used to gain information concerning structures, conformations and aggregation behavior. The mesylates are associated in chloroform; the triflates are not.

Reaction of a Copper−Dioxygen Complex with Nitrogen Monoxide (•NO) Leads to a Copper(II)−Peroxynitrite Species

A discrete peroxynitrite-copper(II) complex, [(TMG3tren)CuII(-OONO)]+ (3), has been generated in solution (ESI-MS, m/z = 565.15; tetragonal EPR) by reacting *NO(g) with superoxo complex [(TMG3tren)CuII(O2*-)]+ (2). Complex 3 undergoes a thermal transformation to give CuII-nitrite complex [(TMG3tren)CuII(-ONO)]+ (4) (X-ray) along with ca. 0.5 molar equiv dioxygen. A DFT calculation derived structure with cyclic bidentate k2-O,O'-OONO bound peroxynitrite moiety and dx2-y2 ground state is proposed. Experiments using 18O2 suggest that the adjacent peroxo oxygen atoms in 3 are derived from molecular oxygen. Further, 18O2 containing 3 undergoes O-O bond cleavage to form singly 18-O-labeled 4. The results suggest the viability of biological CuI/O2/(*NO) peroxynitrite formation and chemistry, that is, not coming from free superoxide plus *NO reaction.

Crystal and molecular structures of the Rh[(C2H5O)2PS2]3 and Co[(C6H5O)2PS2]3 chelate compounds

The crystal structures of the Rh[(EtO)2PS2]3 (I) and Co[(PhO)2PS2]3 (II) chelate compounds were determined from X-ray diffraction (XRD) data (CAD-4 diffractometer, MoKβ radiation, 1193 Fhkl, R = 0.0516 for I and 513 Fhkl, R = 0.0305 for II). Crystals I are monoclinic: a = 14.233(3) A, b = 13.570(3) A, c = 14.272(3) A; β = 90.66(3)°, V = 2756.3(10) A3, Z = 4, ρcalc = 1.587 g/cm3, space group C2/c. Crystals II are trigonal: a = 15.149(2) A, c = 30.306(6) A; V = 6023.2(16) A3, Z = 6, ρcalc = 1.493 g/cm3, space group R3¯. Structures I and II consist of discrete mononuclear molecules. The coordination polyhedra of the M atoms (M = Rh, Co) are distorted octahedra formed by six sulfur atoms of three cyclic bidentate (RO)2 PS2− ligands.

Synthesis, structure, and physicochemical properties of the Cr(iso-Bu2PS2)3 chelate compound

A paramagnetic (µef = 3.86 BM) complex Cr(i-Bu2PS2)3 (I) has been synthesized. Single crystals I were grown, and the crystal structure of the compound was determined from X-ray diffraction data (X8 APEX diffractometer, MoK α radiation, 4516 F hkl , R = 0.0604). Monoclinic crystals, space group P21/n, unit cell parameters a = 14.2665(5) A, b = 11.4400(4) A, c = 23.1299(8) A, β = 90.245(1)°, V = 3775.0(2) A3, Z = 4, d calc = 1.196 g/cm3. The structure is based on discrete mononuclear molecules. The coordination polyhedron of the Cr atom is a distorted S6 octahedron formed from the S atoms of three cyclic bidentate ligands — i-Bu2PS 2 − ions. Electron spectroscopy data correspond to the octahedral structure of the CrS6 chromophore.

Synthesis and crystal and molecular structure of the mixed-ligand coordination compound ZnPhen(n-C4H9OCS2)2

A mixed-ligand complex ZnPhen(n-BuOCS2)2 has been synthesized. The structure of the compound was solved by X-ray diffractometry (X8 APEX diffractometer, MoK α radiation, 4254 F hkl , R = 0.0448). Triclinic crystals with the parameters a = 9.4464(3) A, b = 11.0279(4) A, c = 13.6528(6) A;α = 106.940(1)°, β = 98.382(1)°, γ = 106.347(1)°; V = 1264.72(8) A3; Z = 2, space group 1. P1¯. The structure consists of discrete mononuclear molecules. The polyhedron of the Zn atom is a trigonal bipyramid N2S3 formed by coordination of the N atoms of the bidentate Phen molecules and the sulfur atoms of the monodentate and cyclic bidentate xanthate ligands. Dimer assemblies are formed in the structure due to π-π interactions of Phen molecules.

Crystal and molecular structures of ZnPhen(C2H5OCS2)2 and Zn(2,2′-Bipy)(n-C4H9OCS2)2 mixed-ligand coordination compounds

ZnPhen(EtOCS2)2 (I) and Zn(2,2′-Bipy)(n-BuOCS2)2 (II) mixed-ligand complexes have been synthesized. The structures were solved from X-ray diffraction data (CAD-4 and X8-APEX diffractometers, MoKα radiation, 1879 and 3637 Fhkl, R = 0.0374 and 0.0315). Crystals I are monoclinic with parameters a = 11.678(3) A, b = 19.215(3) A, c = 9.655(1) A; β = 101.23(1)°; V = 2125.0(7) A3; Z = 4, space group P21/c; crystals II are triclinic with parameters a = 8.7875(3) A, b = 11.833(1) A, c = 13.3454(6) A; α = 112.154(2)°, β = 108.503(1)°, γ = 92.787(2)°; V = 1196.2(1) A3; Z = 2, space group 1 \(P\bar 1\). The structures are composed of discrete mononuclear molecules. The polyhedra of the Zn atoms are distorted trigonal bipyramids N2S3 formed by coordination of the N atoms of Phen or 2,2′-Bipy molecules and sulfur atoms of the monodentate and cyclic bidentate xanthogenate ligand. In structures I and II, dimer assemblies are formed by π-π interactions of Phen or 2,2′-Bipy molecules.

Synthesis and structure of (bis(3,5-dimethyl-1H-pyrazol-1-yl)methane)diiodocobalt(II)

A cobalt(II) iodide complex with bis(3,5-dimethyl-1H-pyrazol-1-yl)methane (L) CoLI2 has been synthesized, and its single crystals have been obtained. The complex compound was characterized by electron spectroscopy and X-ray diffraction analysis. The compound crystallizes in the monoclinic system (a = 8.4044(4) A, b = 13.3120(5) A, c = 14.5824(7) A; β = 94.7290(10)°; V = 1625.92(13) A3; Z = 4; ρcalc = 2.112 g/cm3; space group P21/m). The structure of the complex is molecular mononuclear. L is a cyclic bidentate ligand; the coordination polyhedron of cobalt is a CoN2I2 tetrahedron formed by the nitrogen atoms of the pyrazole fragments L and iodine atoms. The complex has π-π stacking interactions between the pyrazole rings of CoLI2 molecules, binding the molecules into infinite chains along the b axis.

Mixed-Ligand Complexes of Ni(i-Bu2PS2)2 with 4-Aminopyridine. Structure of [Ni(4-NH2Py)(i-Bu2PS2)2

Mixed-ligand complexes [Ni(4-NH2Py) (i-Bu2PS2)2] (I) and Ni(4-NH2Py)2(i-Bu2PS2)2 (II) have been synthesized. Single crystals were grown and X-ray diffraction data (CAD-4 diffractometer, MoK α radiation, 1477 F hkl , R = 0.0320) were used to determine the structure of I. The crystals are orthorhombic: a = 10.675(1) A; b = 21.681(2) A; c = 26.302(4) A, V = 6087.5(12) A3, Z = 8, ρ(calc) = 1.247 g/cm3, space group Pbca. Complex I possesses a mononuclear molecular structure. The coordination polyhedron of the Ni atom is a tetragonal pyramid NS4 whose base is formed by four S atoms of two cyclic bidentate ligands i-Bu2PS 2 − and the axial position is occupied by the N atom of the 4-NH2Py cycle. According to electron spectroscopy data, complex II has an octahedral N2S4 environment of the Ni atom.

Crystal Structure of the Mixed-Ligand Compound [HgPhen{(C2H5)2NCS2}2] and the Character of Intermolecular Interactions in [MPhen{(C2H5)2NCS2}2] (M = Zn, Cd, Hg)

Single crystals of the mixed-ligand complex compound [HgPhen(Et2NCS2)2] were obtained. The crystal structure of the compound was determined by X-ray diffraction analysis (CAD-4 diffractometer, Mo $$K_\alpha $$ radiation, 3640 F hkl , R = 0.0280). Triclinic crystals with cell parameters a = 10.308(2), b = 11.171(3), c = 11.552(2) A, α = 94.16(2), β = 96.66(1), γ = 105.17(2)°, V = 1267.8(5) A3, Z = 2, d calc = 1.774 g/cm3, space group $$P\bar 1$$ . The structure is composed of discrete monomer molecules. The coordination polyhedron of the Hg atom is a distorted octahedron formed by four S atoms of the two cyclic bidentate Et2 $$NCS_{2^ - } $$ ligands and two N atoms of the cyclic bidentate Phen ligand. The character of interactions between [MPhen(Et2NCS2)2] (M = Zn, Cd, Hg) molecules and their packing in the structure are considered.

Crystal Structures and Properties of New Mixed-Ligand Complexes of Nickel(II) Diisobutyldithiophosphinate with Imidazole and 3,5-Dimethylpyrazole

The reaction of Ni{(i-C4H9)2PS2}2 with imidazole and 3,5-dimethylpyrazole in ethanol gave paramagnetic (μef = 3.02 and 3.11 BM) mixed-ligand complex compounds [Ni(Im)2{(i-C4H9)2PS2}2] (I) and [Ni(Pyr){(i-C4H9)2PS2}2] (II). Single crystals were grown and the crystal structures of I and II were determined from X-ray diffraction data (CAD-4 diffractometer, Mo\(K_\alpha \) radiation, 1483 \(F_{hkl} \), R = 0.0344 for I and 2630 \(F_{hkl} \), R = 0.0486 for II). The crystals are monoclinic with cell dimensions a = 12.845(2), b = 10.250(1), c = 13.431(1) A, β = 115.89(1)°, V = 1591(1) A3, Z = 2, dcalc = 1.281 g/cm3, space group \(P2_{1/c} \) (for I); a = 11.152(3), b = 12.483(2), c = 23.389(4) A, β = 100.78(1)°, V = 3199(2) A3, Z = 4, dcalc = 1.191 g/cm3, space group \(P2_{1/n} \) (for II). The structures consist of discrete monomer molecules. The coordination polyhedron of the Ni atom is a compressed octahedron NiN2S4 (in I) and a tetragonal pyramid NiNS4 (in II) formed by four S atoms of the two cyclic bidentate ligands i-Bu2\(PS_{2^\_ } \) and the N atoms of two monodentate ligands (Im molecules in trans-positions) or the N atom of the monodentate Pyr ligand in complexes I and II, respectively. The character of interaction between molecules I and II and molecular packing modes are considered. The electronic spectra of the complexes are consistent with the symmetry of chromophores found from X-ray data.

Molecular Packing in the Crystal Structures of Mixed-Ligand Complexes [ZnPhen{(i-C 4 H 9 ) 2 PS 2 } 2 ] and [Zn(2,2′-Bipy){(i-C 4 H 9 ) 2 PS 2 } 2

Volatile mixed-ligand complexes of Zn(i-Bu2PS2)2 with Phen and 2,2′-Bipy have been synthesized. The crystal structures of the complexes ZnPhen{(i-C4H9)2PS2}2 and Zn(2,2′-Bipy){(i-C4H9)2PS2}2 were determined by single crystal X-ray diffractometry (CAD-4 diffractometer, MoKα radiation, 2100 Fhkl, R = 0.0423 for the first complex and 2003 Fhkl, R = 0.0486 for the second). The crystals are monoclinic with cell dimensions a = 17.580(4), b = 9.969(2), c = 19.175(4) A, β = 90.33(3)°, V = 3360(1) A3, Z = 4, d calc = 1.313 g/cm3, space group P2/n (for the Phen complex); a = 24.219(5), b = 11.386(2), c = 24.916(5) A, β = 97.70(3)°, V = 6809(2) A3, Z = 8, d calc = 1.249 g/cm3, space group C2/c (for the 2,2′-Bipy complex). The complexes are constructed from discrete monomer molecules. The coordination polyhedra of the Zn atoms are distorted tetrahedra formed by two S atoms of the two monodentate i-Bu2PS 2 - ligands and two N atoms of the cyclic bidentate Phen or 2,2′-Bipy molecules. Intermolecular interactions and packings in the structures are analyzed.

Monodentate and Bridging Bidentate Functions of 4,4′-Bipyridine in the Crystal Structures of [Zn(4,4′-Bipy){(n-C3H7)2NCS2}2] and [Zn2(4,4′-Bipy){(n-C3H7)2NCS2}4

The structures of the mixed-ligand complexes Zn(4,4′-Bipy){(n-C3H7)2NCS2}2 (I) and Zn2(4,4′-Bipy){(n-C3H7)2NCS2}4 (II) were determined by single crystal X-ray diffractometry (CAD-4 diffractometer, MoKα radiation, 2479 and 1616 Fhkl, R = 0.0550 and 0.0523). The crystals are monoclinic with cell parameters a = 16.560(2), b = 11.423(1), c = 15.319(2) A, β = 94.27(1)°, V = 2889.8(6) A3, Z = 4, space group P21/c (for I) and a = 8.515(1), b = 10.965(1), c = 27.816(3) A, β = 95.860(1)°, V = 2583.5(5) A3, Z = 2, space group P21/n (for II). The structure of I is composed of discrete mononuclear molecules; the structure of II consists of discrete centrosymmetric binuclear molecules. The coordination polyhedra of the Zn atoms (c.n. 5) are formed by four S atoms of the two cyclic bidentate dithiocarbamate ligands and the N atom of the 4,4′-Bipy ligand, which is monodentate in I and bridging bidentate in II. Molecular packings and interactions in the structures are considered.