Synthesis and structural characterization of mercury(II) complexes with a novel ferrocenyliminophosphine

Synthesis of the novel ligand ferrocenyliminophosphine [(η⁵-C₅H₅)Fe{(η⁵-C₅H₄)CHN(C₆H₄-2-PPh₂)}] (1, L) and studies on its complexation properties with mercury (II) are reported. Halogen-bridged binuclear mercury (II) complexes [HgX(μ-X)L]₂ (X = Cl (2a), Br (2b)) and a mononuclear mercury (II) complex HgCl₂L₂ (4a) have been obtained under different reaction conditions. In both cases, the ferrocenyliminophosphine acts as a P-monodentate ligand and the imino nitrogen does not participate in coordination to mercury (II). All the new compounds 1, 2a, 2b and 4a were characterized by elemental analysis, ¹H NMR, ³¹P NMR and IR spectra. In addition, structures of 2a and 4a have been determined by X-ray single-crystal analysis.     

Synthesis and structures of platinum(II) complexes with 5-ferrocenylpyrimidine

Reaction of platinum(II) salts with 5-ferrocenylpyrimidine (FcPM) afforded cis-[Pt(NH₃)₂(FcPM)₂](PF₆)₂ (1), trans-[Pt(NH₃)₂(FcPM)₂](PF₆)₂ (2), cis-[PtCl₂(FcPM)₂] (3), and cis-[PtCl₂(DMSO)(FcPM)] (4): their spectroscopic and electrochemical properties were investigated. Complexes 1 and 2 were structurally characterized by X-ray crystallography.     

Synthesis and crystal structure of a novel binuclear copper(I) complex with bridging monohydrogensulfido (SH) ligands

A novel dinuclear copper(I) complex, [Cu₂(μ₂-SH)₂(PPh₃)₃] (1) (PPh₃ = triphenylphosphine) has been prepared by the reaction of CuCl with triphenylphosphine and mercaptopropanoic acid (MPA) mixed in the ratio of 1:1:1. In the molecular structure of 1, two copper atoms are bridged by S atoms of two monohydrogensulfido anions forming a four-membered ring. The planar Cu₂S₂ core is characterized by significant cuprophilic interactions (Cu-Cu distance = 2.897 ?). One copper atom in 1 is coordinated with two sulfur atoms and one phosphorus atom of PPh₃ adopting a trigonal planar geometry, while the coordination environment around the other copper center is distorted tetrahedral that is completed by two sulfur atoms of SH groups and two phosphorus atoms of PPh₃ molecules.     

Synthesis, crystal structures and properties of novel zinc(II) and cadmium(II) polymeric and cyclic bimetallic complexes with fluconazole and dicarboxylate co-ligands

Four new fluconazole-bridged zinc(II) and cadmium(II) complexes with dicarboxylate co-ligands, namely [Zn(HFlu)(TPA)]_n (1), {[Cd(HFlu)₂(TPA)]·2CH₃OH}_n (2), [Zn(HFlu)₂(Suc)(H₂O)₂]·H₂O (3), and [Cd(HFlu)₂(Suc)(H₂O)₂]·H₂O (4), have been synthesized and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction (HFlu = 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol, H₂TPA = terephthalic acid, and H₂Suc = succinic acid). Complex 1 displays a 2-D corrugated network with common (4,4) topology, in which two types of grids constructed by two bridging TPA dianions and two HFlu ligands are found. Complex 2 shows an unusual (3,6) coordination layer consisting of alternative PMPM Cd-HFlu helical chains in which the Cd(II) nodes are also fixed by terephthalate dianions in a cis fashion. The isostructural complexes 3 and 4 have 20-membered dimeric macrocyclic motifs with the Zn···Zn and Cd···Cd distances of 11.258(2) and 11.528(2) Å, respectively. The fluorescence and thermal stability of complexes 1-4 have also been investigated.     

Synthesis, characterization, and structural studies of mercury(II) complexes of new bidentate phosphorus ylide

The reaction of Ph₂PCH₂CH₂PPh₂ (dppe) with BrCH₂C(O)C₆H₄NO₂ (1:1.05 molar ratio) in acetone produces a mixture of the new monophosphonium salt [Ph₂PCH₂CH₂PPh₂CH₂C(O)C₆H₄NO₂]Br (1) and the diphosphonium salt [NO₂C₆H₄C(O)CH₂PPh₂CH₂CH₂PPh₂CH₂C(O)C₆H₄NO₂]Br₂ (2). Compound 2 was insoluble in acetone and thus easily separated from the solution of 1. Further, by reacting both the mono- and diphosphonium salts with the appropriate bases the bidentate phosphorus ylides, [Ph₂PCH₂CH₂PPh₂CHC(O)C₆H₄NO₂] (3) and [NO₂C₆H₄C(O)CHPPh₂CH₂CH₂PPh₂CHC(O)C₆H₄NO₂] (4) were obtained. The reaction of ligand 3 with mercury(II) halides in dry methanol leads to the formation of the P,P-coordinated monomeric complexes {HgX₂(Ph₂PCH₂CH₂PPh₂CHC(O)C₆H₄NO₂)₂} [X = Cl (5), Br (6), I (7)]. The structure of complex 7 being unequivocally determined by single crystal X-ray diffraction techniques. Characterization of these species was also performed by elemental analysis, IR spectroscopy and ¹H, ³¹P, and ¹³C NMR techniques. These analyses being consistent with a 2:1 stoichiometry ylide/Hg(II) for compounds 5 through 7. Results obtained from theoretical studies are also consistent with a product in which two ylides are coordinated to the Hg(II) center through their phosphine groups, being this product the most stable among all the possible products.     

Synthesis and spectroscopy of diethyl (pyridinylmethyl)phosphates and their palladium (II) complexes: X-ray crystal structures of Pd(II) complexes

The synthesis of diethyl (pyridin-2-, -3-, -4-ylmethyl)phosphate (2-pmOpe, 3-pmOpe, 4-pmOpe) ligands and their palladium (II) complexes of general formula trans-[PdCl₂L₂] (L = 2-pmOpe, 3-pmOpe,4-pmOpe) has been described. Pyridine phosphate derivatives were synthesized via the condensation of phosphorochloridic acid diethyl ester with an appropriate pyridinylmethanol in the presence of triethylamine. The compounds have been identified and characterized by IR, far-IR, ¹H NMR, ³¹P NMR, ³¹P CP-MAS NMR and elemental analyses. The crystal and molecular structures of palladium (II) complexes, i.e., [PdCl₂(2-pmOpe)₂] and [PdCl₂(4-pmOpe)₂] determined by the X-ray diffraction method, are presented. In both structures, Pd(II) ions are four-coordinated by two chlorine atoms and two pyridine nitrogen atoms. The geometry of complexes is square-planar and adopt a trans configuration, which is consistent with preparation method.     

Synthesis and crystal structures of di- and tetra-nuclear dicarboxylate-bridged copper(II) complexes

Three new Cu(II) complexes, [Cu₂(C₃H₂O₄)(phen)₂(H₂O)₃](NO₃)₂(H₂O)₂ (1) (C₃H₂O₄ = malonate, phen = 1,10-phenanthroline), [Cu₂(C₄H₄O₄)(phen)₂(H₂O)₂](NO₃)₂ (2) (C₄H₄O₄ = succinate), and {[Cu₂(phen)₂(H₂O)(NO₃)]₂(C₅H₆O₄)₂}(NO₃)₂ (3) (C₅H₆O₄ = glutarate) have been synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. The X-ray analysis reveals that the structures of 1 and 2 are of dinuclear copper(II) complexes bridged by malonate and succinate dianions, respectively, and 3 is a tetranuclear species formed by two {[Cu₂(phen)₂(H₂O)(NO₃)](C₅H₆O₄)} fragments. The copper ions in 1 and 3 show square-pyramidal coordination geometry, while the copper ions in 2 exhibit a square planar geometry. In each complex, the dicarboxylate ligand is coordinated to copper ions as a chelate and monodentate (1), bis-monodentate (2), and bis-bridging ligand toward the copper ions with syn-syn coordination mode (3).     

Synthesis, structures, and characterization of benzildiimine complexes of rhodium(III) and iridium(I)

The reactions of trans-[(PPh₃)₂M(CO)Cl] (M = Rh and Ir) with benzildiimine (H₂BDI = 2) derived from benzil-bis(trimethylsilyl)diimine (Si₂BDI) (1) in a 1:2 and 1:1 molar ratio afforded the cationic bis-benzildiiminato complexes [Rh(PPh₃)₂(HBDI)₂]Cl (3) and the mono-benzildiimine complex [Ir(PPh₃)₂(CO)(H₂BDI)]Cl (4), respectively. Both complexes are fully characterized using IR, FAB-MS, NMR spectroscopy and elemental analysis. The single crystal X-ray structure analysis reveals a distorted octahedral coordination geometry for the Rh(III) in 3 and a highly distorted square pyramidal geometry for Ir(I) in 4. In addition, the solid-state structure of Si₂BDI is reported here for the first time showing the substituents highly twisted because of steric reasons.     

Construction of a series of mercury(II) complexes based on a bis-pyridyl-bis-amide ligand: Effect of counter anions, interactions on the supermolecular structures

Four new complexes, [Hg(L)Cl₂]₂ (1), [Hg(L)Br₂]₂ (2), [Hg(L)I₂(DMF)₂]_n (3), and [HgLCl(SCN)]_n (4) (L = N,N-bis-(3-pyridyl)isophthalamide) were obtained through the self-assembly of a rigid conjugated clamp-like bis-pyridyl-bis-amide ligand L with HgX₂ (X = Cl for 1, Br for 2, I for 3, and Cl for 4 with the addition of KSCN) and characterized by single crystal X-ray diffraction, elemental analysis, IR spectrum, etc. Employments of different anions result in different structures. Complexes 1 and 2 feature bimetallic macrocycle formed by coordinating two Hg(II) metal centers by two ligands which are in syn-syn conformation. The macrocyclic subunits further self-assemble into a porous macrocycle structure via the hydrogen-bonding and π-π stacking interactions. Introduction of I⁻ and SCN⁻ ions bring about stronger steric hindrance effect. Complexes 3 and 4 are polymers with infinite 1D polymeric chain in herringbone fashion and the hydrogen-bonding interactions and π-π stacking interactions between the parallel benzene rings and the pyridyl rings stabilize the supromolecular framework. Furthermore, we measured their fluorescent properties in the solid state at room temperature and XRD properties also have been determined.     

Synthesis, vibrational spectra and X-ray structures of copper(I) thiourea complexes

Complex formation of thiourea with copper takes place as an intermediate step in the preparation of copper sulfide thin films by spray pyrolysis starting from aqueous solutions of copper(II) chloride and thiourea. The stoichiometry of the complex and that of the resulting thin film primarily depends on the molecular ratio of the starting materials. For comparison, the structures of all copper(I) thiourea complexes found in the Cambridge Structural Database are classified in this paper. In addition, syntheses, structural (single crystal XRD also at low temperature 193 K) and spectroscopic studies (FTIR and Raman) of six copper-thiourea complexes are now reported. The copper to thiourea stoichiometric ratio is 1:3 in four of these complexes, but their structures are basically different as dimerization or polymer formation takes place depending on whether the water of crystallisation is present or absent. The structure of bis(μ-thiourea)tetrakis(thiourea)dicopper(I) dichloride dihydrate, [Cu₂(tu)₆]Cl₂ · 2H₂O (1) was determined at room and also at low temperature. Bis(μ-thiourea)tetrakis(thiourea)dicopper(I) dibromide dihydrate, [Cu₂(tu)₆]Br₂ · 2H₂O (2) is isomorphous with 1, like the anhydrous compounds chlorotris(thiourea)copper(I), [Cu(tu)₃]Cl (3) and bromotris(thiourea)copper(I), [Cu(tu)₃]Br (4) are isomorphous. In the third isomorphous pair of complexes the copper to thiourea stoichiometric ratio is 1:1, viz. chloro(thiourea)copper(I) hemihydrate, [Cu(tu)]Cl · 0.5H₂O (5) and bromo(thiourea)copper(I) hemihydrate, [Cu(tu)]Br · 0.5H₂O (6). During the preparation of chloro(thiourea)copper(I) hemihydrate (5) a reaction by product α,α^′-dithiobisformamidinium dichloride, [SC(NH₂)₂]₂Cl₂ (7) was identified and structurally characterized which made it possible to suggest a reaction path leading to complex formation.     

Pd(II) complexes containing N-alkyl-3-pyridine-5-trifluoromethyl pyrazole ligands: Synthesis, NMR studies and X-ray crystal structures

Palladium [PdCl₂(L)] complexes with N-alkylpyridylpyrazole derived ligands [2-(5-trifluoromethyl-1H-pyrazol-3-yl)pyridine (L¹), 2-(1-ethyl-5-trifluoromethyl-1H-pyrazol-3-yl)pyridine (L²), 2-(1-octyl-5-trifluoromethyl-1H-pyrazol-3-yl)pyridine (L³), and 2-(3-pyridin-2-yl-5-trifluoromethyl-pyrazol-1-yl)ethanol (L⁴) were synthesised. The crystal and molecular structures of [PdCl₂(L)] (L = L², L³, L⁴) were resolved by X-ray diffraction, and consist of monomeric cis-[PdCl₂(L)] molecules. The palladium centre has a typical square-planar geometry, with a slight tetrahedral distortion. The tetra-coordinate metal atom is bonded to one pyridinic nitrogen, one pyrazolic nitrogen and two chlorine ligands in cis disposition. Reaction of L (L², L⁴) with [Pd(CH₃CN)₄](BF₄)₂, in the ratio 1M:2L, gave complexes [Pd(L)]₂(BF₄)₂. Treatment of [PdCl₂(L)] (L = L², L⁴) with NaBF₄ and pyridine (py) and treatment of the same complexes with AgBF₄ and triphenylphosphine (PPh₃) yielded [Pd(L)(py)₂](BF₄)₂ and [Pd(L)(PPh₃)₂](BF₄)₂ complexes, respectively. Finally, reaction of [PdCl₂(L⁴)] with 1 equiv of AgBF₄ yields [PdCl(L⁴)](BF₄).     

Synthesis and structures of pyridinecarboxylate-containing zinc(II) complexes in dien and tren system

Four new zinc(II) complexes [Zn(dien)(μ-nic)]₂(BPh₄)₂·2CH₃OH (1), {[Zn(dien)(isonic)]BPh₄}_n (2), [Zn(tren)(nic)]BPh₄ (3) and [Zn(tren)(isonic)]BPh₄ (4) (dien/tren = diethylenetriamine/triethylenetriamine, nic/isonic = nicotinate/isonicotinate anion) were synthesized and structurally characterized by IR, ¹H NMR and single crystal X-ray diffraction. In the zinc(II) complexes of dien, both nicotinate and isonicotinate connect the zinc(II) ions via N,O-bis-monodentate mode. Complex 1 contains a centrosymmetric dinuclear unit bridged by two nicotinate anions in anti-parallel way. Complex 2 is characterized by an infinite one-dimensional zigzag chain bridged by isonicotinate anion in an end-to-end mode. The Zn···Zn distance is 6.782 for 1 and 8.805 Å for 2. While in the complexes of tren, both 3 and 4 are mononuclear complexes with nicotinate and isonicotinate coordinated to zinc(II) ion through only one oxygen atom of their carboxylate groups. The zinc(II) ions in all of the four complexes are in a distorted trigonal bipyramidal geometry. Complex 3 forms a dinuclear unit and complex 4 forms an infinite 2D sheet structure through intermolecular H-bonds. In all of the crystal lattices, the counterions act to balance the electronic charge at the same time to construct different 3D structures through noncovalent interactions such as C-H···π, N-H···π and van der Waals interactions.     

Ladder-like azido-bridged copper(II) complexes: Synthesis, X-ray structure and magnetic study

Two mixed-ligand copper(II) complexes [{Cu(L¹)(μ_1,3-N₃)}{Cu(L)(μ_1,3-N₃)(μ_1,1-N₃)}]_n (1) [HL¹ = 1-(N-ortho-hydroxyacetophenimino)-2,2-dimethyl-aminoethane; L = 2-(dimethylamino)-ethylamine] and [{Cu(L²)(μ_1,3-N₃)}{Cu(L)(μ_1,3-N₃)(μ_1,1-N₃)}]_n (2) [HL² = 1-(N-5-methoxy-ortho-hydroxyacetophenimino)-2,2-dimethyl-aminoethane] have been formed upon addition of aqueous solution of sodium azide to a methanolic solution of copper nitrate trihydrate and corresponding Schiff-base ligands. The ligands, HL¹ and HL² undergo partial hydrolysis of their imine bond during the course of reaction. Both the complexes contain single end-to-end (μ_1,3) azido bridged 1D infinite chains (rail) which propagate parallel to the crystallographic b-axis; neighboring chains are interconnected by pairs through double asymmetric end-on (μ_1,1) azido bridges (rung) to yield a ladder-like structure. In both complexes, rungs (end-on azido bridges) do not connect copper centers of the chains like in a regular ladder; instead they connect only the alternating copper sites of the 1D chain. In a chain the coordination environment around copper(II) ions are not the same: while the {Cu(L¹)(μ_1,3-N₃)} and {Cu(L²)(μ_1,3-N₃)} moieties have a penta-coordinated copper(II) center, the copper(II) ion of the neighboring {Cu(L¹)(μ_1,3-N₃)(μ_1,1-N₃)} or {Cu(L²)(μ_1,3-N₃)(μ_1,1-N₃)} moiety has an octahedral coordination environment. The variable temperature (2-300 K) magnetic susceptibility measurements showed that the magnetic interaction between the metal centers in complexes 1 and 2 is dominantly antiferromagnetic. The results of magnetic model are in good agreement with the experimental data.     

Synthesis, structures and magnetic properties of nickel(II), manganic(II) and zinc(II) complexes containing pyridyl-substituted nitronyl nitroxide and tris(2-benzimidazolymethyl)amine

Three new magnetic compounds were synthesized by using 2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NIT2Py) and tris(2-benzimidazolymethyl)amine (NTB) as ligands. The structures and magnetic properties of the complexes with formula [Ni(NIT2Py)(NTB)](ClO₄)₂(CH₃OH) 1, [Mn(NIT2Py)(NTB)](ClO₄)₂2 and {[Zn(NIT2Py)₂(CH₃OH)₂](ClO₄)₂}{[Zn(NTB)(H₂O)](ClO₄)₂} 3 were characterized. Compounds 1 and 2 both have [M(NIT2Py)(NTB)] structural units, where the metal ion is in an octahedral environment bound to one NIT2Py through one pyridyl nitrogen atom and one nitroxide oxygen atom. However, compound 3, the chelating zinc ion has two crystallographically independent molecules in the asymmetric unit: one is six coordinated octahedral structure [Zn(NIT2Py)₂(CH₃OH)₂](ClO₄)₂, and the other one is five coordinated pyramidal structure [Zn(NTB)(H₂O)](ClO₄)₂. The magnetic behaviors of these compounds indicate that both the nickel ion and the manganese ion are antiferromagnetically coupled with the NIT2Py ligand with a coupling constant of −19.44 and −0.37 cm⁻¹, respectively, whereas two NIT2Py ligands in compound 3 are ferromagnetically coupled with a coupling constant of 19.1 cm⁻¹.     

Synthesis, characterization and crystal structures of Cd(II) and Zn(II) complexes with 2,2′-biimidazole

The reactions of zinc and cadmium salts with 2,2′-biimidazole (H₂biim) yielded a series of compounds in which the ligand is coordinated in the chelating bidentate mode. ZnCl₂ and [Ag(H₂biim)](NO₃) in methanol in a 2:1 proportion produced Zn(H₂biim)Cl₂, in which the metal has a distorted tetrahedral coordination. A 1:2 ratio led to [Zn(H₂biim)₂(CH₃OH)₂](NO₃)₂, containing an octahedrally coordinated Zn(II) center with the O-bonded methanol ligands occupying trans positions. The corresponding [Cd(H₂biim)₂(CH₃OH)₂](NO₃)₂ compound was obtained from CdCl₂. By starting with Cd(NO₃)₂ and Cd(ClO₄)₂ in aqueous media, the related octahedral bis-chelate compounds [Cd(H₂biim)₂(NO₃)(H₂O)](NO₃) and Cd(H₂biim)₂(ClO₄)₂, respectively, were isolated, the apical positions being filled by perchlorate oxygens in the latter case. With Cd(BF₄)₂, the glass container participated in the reaction and a tris-chelate complex [Cd(H₂biim)₃]₂(SiF₆)(BF₄)₂ · 6EtOH was isolated. The [Cd(H₂biim)₃]²⁺ and ions define an extended hydrogen-bonded network, in which ions surrounded by disordered ethanol molecules occupy large cavities. The two free N-H groups provide H₂biim with a unique ability to form hydrogen bonds and their interactions with counter anions or other acceptors play a determining role in controlling molecular packing. The IR spectra of all compounds are discussed.     

Synthesis, structures and magnetic properties of nicotinato-copper(II) complexes with polybenzimidazole and polyamine ligands

Four novel nicotinato-copper(II) complexes containing polybenzimidazole and polyamine ligands were synthesized with formula [Cu₂(bbma)₂(nic)₂](ClO₄)₂·CH₃OH·0.5H₂O (1), [Cu₂(dien)₂(nic)₂](ClO₄)₂·2CH₃OH (2), [Cu(ntb)(nic)]ClO₄·H₂O (3) and [Cu(tren)(nic)]BPh₄·CH₃OH·H₂O (4), in which bbma is bis(benzimidazol-2-yl-methyl)amine, dien is diethylenetriamine, ntb is tris(2-benzimidazolylmethyl)amine, tren is tris(2-aminoethyl)amine and nic is nicotinate anion. All of the complexes were characterized by elemental analysis, IR and X-ray diffraction analysis. Complexes 1 and 2 contain centrosymmetric dinuclear entity with the two Cu(II) atoms bridged by two nicotinate anions in an anti-parallel mode. The Cu···Cu separation is 7.109 Å for 1 and 6.979 Å for 2. Complexes 3 and 4 are mononuclear with nicotinate coordinated to Cu(II) ion by the carboxylate O atom in 3 and the pyridine N atom in 4. All of the complexes exhibit abundant hydrogen bonds to form 1D chain for 1, 3, 4 and 2D network for 2. Magnetic susceptibility measurements over the 2-300 K range reveal very weak ferromagnetic interaction between the two Cu(II) ions in 1 and antiferromagnetic interaction in 2 mediated by nicotinate ligand, with J value to be 0.15 and −0.19 cm⁻¹, respectively.     

Synthesis, structures and properties of dinuclear cadmium(II) complexes based on polybenzimidazole binucleating ligands

Three novel cadmium(II) complexes [Cd₂(tbpo)(O₂CC₆H₄-p-NO₂)₂]ClO₄·3CH₃OH (1) [Cd₂(bbap)(O₂CC₆H₄-p-NO₂)₂]ClO₄·4.5CH₃OH·0.75H₂O (2) and [Cd(ntb)(O₂CC₆H₄-p-NO₂)]ClO₄·4CH₃OH (3) have been synthesized and characterized by IR, elemental analysis, ¹H NMR and X-ray crystallography, where tbpo⁻ and bbap⁻ are anions of N,N,N′,N′-tetrakis(2-benzimidazolylmethyl)-2-hydroxo-1,3-diaminopropane and 2,6-bis[bis(2-benzimidazolylmethyl)aminomethyl]-4-methylphenol, respectively; ntb is tris(2-benzimidazolymethyl)amine. Complexes 1 and 2 contain μ-phenolate-bridged and μ-alkoxo-bridged dicadmium(II) cores with the Cd1?Cd2 separation of 3.671 Å for complex 1 and 3.718 Å for 2. One of the 4-nitrobenzoate anions bridged the two cadmium(II) ions in syn-anti mode through its carboxylate group, the other 4-nitrobenzoate is only coordinated with Cd2 in bidentate chelating mode. The two central cadmium(II) atoms are in trigonal bipyramidal and pentagonal bipyramidal geometry. In complex 3, the cadmium(II) atom is coordinated with four nitrogen atoms of ntb and one carboxylate oxygen atom of 4-nitrobenzoate in distorted trigonal bipyramidal geometry. Experiment shows that there is a higher affinity of 4-nitrobenzoate anion as coligand with the dinuclear [Cd₂(tbpo)]³⁺ and [Cd₂(bbap)]³⁺ cores than that with the mononuclear [Cd(ntb)]²⁺ core.     

Syntheses, structures and photoluminescence properties of cadmium(II) and zinc(II) complexes with pyridinylcarboxamide-containing ligand

Four new coordination complexes [Cd(DPBA-3)₂(H₂O)₂](ClO₄)₂·2H₂O (1), [Cd(DPBA-3)(DMF)(NO₃)₂]·DMF (2), [Cd₃(DPBA-3)₂(SCN)₆]·2DMF·4H₂O (3) and [Zn(DPBA-3)(SCN)₂] (4) [DPBA-3 = N,N′-di(pyridin-3-yl)pyridine-3,5-dicarboxamide] have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Complexes 1, 3 and 4 exhibit three different types of one-dimensional (1D) chain structures constructed by the metal ions and DPBA-3 ligands, and the Cd(II)-DPBA-3 1D chains in 3 are further linked by bridging SCN⁻ ligands to afford a three-dimensional (3D) framework. Complex 2 possesses a (6,3) two-dimensional (2D) layer structure. In 1-4, the hydrogen bonds involving the amide groups play important role to stabilize the resultant frameworks. The photoluminescence properties of the DPBA-3 and the complexes were studied in the solid state at room temperature.     

Stereochemically non-rigid helical mercury(II) complexes

Reactions of the 1:2 condensate (L) of benzil dihydrazone and 2-acetylpyridine with Hg(ClO₄)₂ · xH₂O and HgI₂ yield yellow [HgL₂](ClO₄)₂ (1) and HgLI₂ (2), respectively. Homoleptic 1 is a 8-coordinate double helical complex with a Hg(II)N₈ core crystallising in the space group Pbca with cell dimensions: a = 16.2250(3), b = 20.9563(7), c = 31.9886(11) Å. Complex 2 is a 4-coordinate single helical complex having a Hg(II)N₂I₂ core crystallising in the space group P2₁/n with cell dimensions a = 9.8011(3), b = 17.6736(6), c = 16.7123(6) Å and β = 95.760(3)^o. In complex 1, the N-donor ligand L uses all of its binding sites to act as tetradentate. On the other hand, it acts as a bidentate N-donor ligand in 2 giving rise to a dangling part. From variable temperature ¹H NMR studies both the complexes are found to be stereochemically non-rigid in solution. In the case of 2, the solution process involves wrapping up of the dangling part of L around the metal.     

Triorganotin(IV) complexes of Schiff base derived from 6-amino-2-mercaptobenzothiazole: Synthesis, characterization and X-ray crystal structures

Nine triorganotin(IV) complexes of the type R₃SnL (L = L1 R = Me 1, Ph 2, PhCH₂3; L = L2 R = Me 4, Ph 5, PhCH₂6; L = L2 R = Me 7, Ph 8, PhCH₂9) have been obtained by reaction of new Schiff base HL1, HL2 or HL3 with triorganotin(IV) chloride in the presence of sodium ethoxide. All the complexes 1-9 were characterized by elemental, IR and NMR spectra analyses. Except for complexes 3, 4, 6, 9, the others were also characterized by X-ray crystallography diffraction analyses, which revealed that complexes 1, 2, 5, 7, 8 were four coordinated and displayed a capped tetrahedron.