Synthesis,structure and in vitro cytotoxicity of platinum(II) complexes containing eugenol and a quinolin‐8‐ol‐derived chelator

The synthesis of potassium (η²‐4‐allyl‐2‐methoxyphenol)trichloridoplatinate(II), K[PtCl₃(C₁₀H₁₂O₂)], ( 1 ), starting from Zeise's salt and Ocimum sanctum L. oil has been optimized. Starting from ( 1 ), three new platinum(II) complexes, namely (η²‐4‐allyl‐2‐methoxyphenol)chlorido(2‐methylquinolin‐8‐olato‐κ²N ,O )platinum(II), ( 2 ), (η²‐4‐allyl‐2‐methoxyphenol)chlorido(5‐nitroquinolin‐8‐olato‐κ²N ,O )platinum(II), ( 3 ), and (η²‐4‐allyl‐2‐methoxyphenol)chlorido(5,7‐dichloroquinolin‐8‐olato‐κ²N ,O )platinum(II), [Pt(C₉H₄Cl₂NO)Cl(C₁₀H₁₂O₂)], ( 4 ), containing eugenol and a quinolin‐8‐ol derivative (R‐OQ), have been synthesized and characterized by elemental analyses, MS, IR, ¹H NMR and NOESY spectra. For ( 1 ) and ( 4 ), single‐crystal X‐ray diffraction studies were also carried out. Complexes ( 2 )–( 4 ) show good inhibiting abilities on three human cancer cell lines, i.e. KB, Hep‐G2 and LU, with IC₅₀ values of 1.42–17.8 µM . Complex ( 3 ) gives an impressively high activity against KB, Hep‐G2, LU and MCF‐7, with IC₅₀ values of 1.42–4.91 µM , which are much lower than those of cisplatin and some other platinum(II) complexes.     

Luminescent Amphiphilic 2,6‐Bis(1‐alkylpyrazol‐3‐yl)pyridyl Platinum(II) Complexes: Synthesis,Characterization, Electrochemical,Photophysical, and Langmuir–Blodgett Film Formation Studies

Two series of novel platinum(II) 2,6‐bis(1‐alkylpyrazol‐3‐yl)pyridyl (N5Cn) complexes, [Pt(N5Cn)Cl][X] ( 1 – 9 ) and [Pt(N5Cn)(C?CR)][X] ( 10 – 13 ) (X=trifluoromethanesulfonate (OTf) or PF₆; R=C₆H₅, C₆H₄‐p‐CF₃ and C₆H₄‐p‐N(C₆H₅)₂), with various chain lengths of the alkyl groups on the nitrogen atom of the pyrazolyl units have been successfully synthesized and characterized. Their electrochemical and photophysical properties have been studied. Some of their molecular structures have also been determined by X‐ray crystallography. Two amphiphilic platinum(II) 2,6‐bis(1‐tetradecylpyrazol‐3‐yl)pyridyl (N5C14) complexes, [Pt(N5C14)Cl]PF₆ ( 7 ) and [Pt(N5C14)(C?CC₆H₅)]PF₆ ( 13 ), were found to form stable and reproducible Langmuir–Blodgett (LB) films at the air–water interface. The characterization of such LB films has been investigated by the study of their surface pressure–area (π–A) isotherms, UV/Vis spectroscopy, XRD, X‐ray photoelectron spectroscopy (XPS), FTIR, and polarized IR spectroscopy. The luminescence property of 13 in LB films has also been studied.     

On the reactivity of platina‐β‐diketones: a straightforward synthesis of trans‐acetylchlorobis(phosphine)platinum(II) complexes and their reactivity

The platina‐β‐diketone [Pt₂{(COMe)₂H}₂(µ‐Cl)₂] ( 1 ) was found to react with monodentate phosphines to yield acetyl(chloro)platinum(II) complexes trans‐[Pt(COMe)Cl(PR₃)₂] (PR₃ = PPh₃, 2a ; P(4‐FC₆H₄)₃, 2b ; PMePh₂, 2c ; PMe₂Ph, 2d ; P(n‐Bu)₃, 2e ; P(o‐tol)₃, 2f ; P(m‐tol)₃, 2g ; P(p‐tol)₃, 2h ). In the reaction with P(o‐tol)₃ the methyl(carbonyl)platinum(II) complex [Pt(Me)Cl(CO){P(o‐tol)₃}] ( 3a ) was found to be an intermediate. On the other hand, treating 1 with P(C₆F₅)₃ led to the formation of [Pt(Me)Cl(CO){P(C₆F₅)₃}] ( 3b ), even in excess of the phosphine. Phosphine ligands with a lower donor capability in complexes 2 and the arsine ligand in trans‐[Pt(COMe)Cl(AsPh₃)₂] ( 2i ) proved to be subject to substitution by stronger donating phosphine ligands, thus forming complexes trans‐[Pt(COMe)Cl(L)L′] (L/L′ = AsPh₃/PPh₃, 4a ; PPh₃/P(n‐Bu)₃, 4b ) and cis‐[Pt(COMe)Cl(dppe)] ( 4c ). Furthermore, in boiling benzene, complexes 2a – 2c and 2i underwent decarbonylation yielding quantitatively methyl(chloro)platinum(II) complexes trans‐[Pt(Me)Cl(L)₂] (L = PPh₃, 5a ; P(4‐FC₆H₄)₃, 5b ; PMePh₂, 5c ; AsPh₃, 5d ). The identities of all complexes were confirmed by ¹H, ¹³C and ³¹P NMR spectroscopy. Single‐crystal X‐ray diffraction analyses of 2a ·2CHCl₃, 2f and 5b showed that the platinum atom is square‐planar coordinated by two phosphine ligands (PPh₃, 2a ; P(o‐tol)₃, 2f ; P(4F‐C₆H₄)₃, 5b ) in mutual trans position as well as by an acetyl ligand ( 2a, 2f ) and a methyl ligand ( 5b ), respectively, trans to a chloro ligand. Single‐crystal X‐ray diffraction analysis of 3b exhibited a square‐planar platinum complex with the two π‐acceptor ligands CO and P(C₆F₅)₃ in mutual cis position (configuration index: SP‐4‐3). Copyright © 2005 John Wiley & Sons, Ltd.     

Crystallization experiments with the dinuclear chelate ring complex di‐μ‐chlorido‐bis[(η2‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC1)platinum(II)]

Crystallization experiments with the dinuclear chelate ring complex di‐μ‐chlorido‐bis[(η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)platinum(II)], [Pt₂(C₁₅H₁₉O₄)₂Cl₂], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform–diethyl ether or methylene chloride–diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile‐κN)(η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chloridoplatinum(II) monohydrate, [Pt(C₁₅H₁₉O₄)Cl(CH₃CN)]·H₂O, (η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chlorido(dimethylformamide‐κO)platinum(II), [Pt(C₁₅H₁₉O₄)Cl(C₂H₇NO)], and (η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chlorido(dimethyl sulfoxide‐κS)platinum(II), determined as the analogue {η²‐2‐allyl‐4‐methoxy‐5‐[(ethoxycarbonyl)methoxy]phenyl‐κC¹}chlorido(dimethyl sulfoxide‐κS)platinum(II), [Pt(C₁₄H₁₇O₄)Cl(C₂H₆OS)]. The crystal structures confirm that acetonitrile interacts with the Pt^II atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt—Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C—H…O and C—H…π interactions, but no π–π interactions are observed despite the presence of the aromatic ring.     

Ionic Self‐Assembly and Red‐Phosphorescence Properties of a Charged Platinum(II) 8‐Quinolinol Complex Associated with Ammonium‐Based Amphiphiles

A series of ionic associates based on the platinum(II) chelate of 5‐sulfo‐8‐quinolinol, [Pt(qS)₂]^2?, and ammonium‐based amphiphiles is described. At variance with the prototypical neutral complex Pt(q)₂ (q=8‐quinolinol), these dianionic fluorophores, functionalized at the periphery with sulfonate groups, can be associated by the ionic self‐assembly approach with various ammonium cations, such as (H_{2 n+1}C_n)₂Me₂N⁺ (n=12, 16, 18) or complex ammonium cations carrying three C_n carbon chains (n=12, 14, 16) and an additional amide group. Investigations of their luminescence properties in solution, in the solid state, and, when possible, in thin films revealed that the phosphorescence properties in condensed phases are directly correlated to intermolecular interactions between the luminescent [Pt(qS)₂]^2? centers. Of particular interest is also the formation of a columnar liquid‐crystalline phase around room temperature (between ?25 and +180 °C), as well as the very good film‐forming ability of some of these fluorophores from organic solvents.     

Bis(8‐quinolinolato‐N,O)platinum(II) and its synthetic intermediate, 8‐hydroxyquinolinium dichloro(8‐quinolinolato‐N,O)platinate(II) tetrahydrate

Bis(8‐quinolinolato‐N,O)­platinum(II), [Pt(C₉H₆NO)₂], (I), has a centrosymmetric planar structure with trans coordination. The molecules form an inclined π stack, with an interplanar spacing of 3.400 (6) Å. 8‐Hydroxy­quinolinium dichloro(8‐quinolinolato‐N,O)­platinate(II) tetrahydrate, (C₉H₈NO)[PtCl₂(C₉H₆NO)]·4H₂O, (II), is soluble in water and is regarded as the synthetic intermediate of the insoluble neutral compound (I). The uncoordinated 8‐hydroxy­quinolinium cations and the monoquinolinolate complexes form an alternating π stack. The origins of fluorescence and phosphorescence in (II) are assigned to the 8‐hydroxy­quinolinium cation and the monoquinolinolate–Pt complex, respectively.     

A Dicationic Organoplatinum(II) Complex Containing a Bridging 2,5‐Bis‐(4‐ethynylphenyl)‐[1,3,4]oxadiazole Ligand Behaves as a Phosphorescent Gelator for Organic Solvents

A dicationic platinum(II) terpyridyl complex, [(tBu₃tpy)Pt(OXD)Pt(tBu₃tpy)](PF₆)₂ (tBu₃tpy=4,4′,4“‐tri‐tert‐butyl‐2,2′:6′,2”‐terpyridyl, OXD=2,5‐bis(4‐ethynylphenyl)[1,3,4]oxadiazole) formed phosphorescent organogels in acetonitrile or in a mixture of acetonitrile and alcohol. The structure and properties of these emissive gels were analyzed by polarizing optical and confocal laser scanning microscopy, and by variable‐temperature ¹H NMR, UV/Vis, and emission spectroscopy. Dry gels were studied by scanning electron microscopy, powder X‐ray diffraction (PXRD), and small‐angle X‐ray scattering (SAXS). SEM images of the dry gel revealed a network of interwoven nanofibers (diameter 12–60 nm, length>5 μm). Intermolecular π–π interactions between the [(tBu₃tpy)PtC≡C] moieties could be deduced from the variable ¹H NMR spectra. The PXRD and SAXS data showed that the assembly of the gelator could be represented by a rectangular 2D lattice of 68 Å × 14 Å. The ability of the complex to gelate a number of organic solvents is most likely due to intermolecular π–π interactions between the [(tBu₃tpy)PtC≡C] moieties.     

π–π Stacking‐Interlinked Molecular Squares with Hepta‐Coordinated Cadmium(II) Corners, [Cd(DMAP)3(NO2)2]·0.5H2O

The single crystal X‐ray analysis data of the new hepta‐coordinate cadmium(II) complex of N,N‐dimethyl‐N‐(4‐pyridyl)amine (DMPA), [Cd(DMPA)₃(NO₂)₂]·0.5H₂O, shows that the coordination environment around the Cd^II is pentagonal bipyramidal. Furthermore, self‐assembly of this complex as molecular squares that interlink via π–π stacking interactions is observed. This network contains voids that are filled by water molecules.     

Red and yellow solvates of chloro­(2,2′:6′,2′′‐terpyridine)platinum(II) chloride and Pt⋯Pt inter­actions

Crystallization of chloro­(2,2′:6′,2′′‐terpyridine)platinum(II) chloride from dimethyl sulfoxide yields a red polymorph, [PtCl(C₁₅H₁₁N₃)]Cl·C₂H₆OS, (I), which exhibits stacking along the a axis through pairs of Pt⋯Pt(−x, −y, −z) inter­actions of 3.3155 (8) Å. The cations are further associated through close Pt⋯Pt(1 − x, −y, −z) distances of 3.4360 (8) Å. Recrystallization from water gives a mero­hedrally twinned yellow–orange dihydrate form, [PtCl(C₁₅H₁₁N₃)]Cl·2H₂O, (II), with pairwise short Pt⋯Pt(1 − x, 2 − y, −z) contacts of 3.3903 (5) Å but no long‐range stacking through the crystals. Inter­pair Pt⋯Pt(−x, 2 − y, −z) distances between cation pairs in the hydrate are 4.3269 (5) Å.     

On the Reactivity of Platina‐β‐diketones – Synthesis and Characterization of Acylplatinum(II) Complexes

The platina‐β‐diketones [Pt₂{(COR)₂H}₂(μ‐Cl)₂] ( 1 , R = Me a , Et b ) react with phosphines L in a molar ratio of 1 : 4 through cleavage of acetaldehyde to give acylplatinum(II) complexes trans‐[Pt(COR)Cl(L)₂] ( 2 ) (R/L = Me/P(p‐FC₆H₄)₃ a , Me/P(p‐CH₂=CHC₆H₄)Ph₂ b , Me/P(n‐Bu)₃ c , Et/P(p‐MeOC₆H₄)₃ d ). 1 a reacts with Ph₂As(CH₂)₂PPh₂ (dadpe) in a molar ratio of 1 : 2 through cleavage of acetaldehyde yielding [Pt(COMe)Cl(dadpe)] ( 3 a ) (configuration index: SP‐4‐4) and [Pt(COMe)Cl(dadpe)] (configuration index: SP‐4‐2) ( 3 b ) in a ratio of about 9 : 1. All acyl complexes were characterized by ¹H, ¹³C and ³¹P NMR spectroscopy. The molecular structures of 2 a and 3 a were determined by single‐crystal X‐ray diffraction. The geometries at the platinum centers are close to square planar. In both complexes the plane of the acyl ligand is nearly perpendicular to the plane of the complex (88(2)° 2 a , 81.2(5)° 3 a ).     

Zur Reaktivität von dinuklearen Platina‐β‐diketonen gegenüber Phosphanen: Diacetylplatin(II)‐Komplexe und mononukleare Platina‐β‐diketone

The Reactivity of Dinuclear Platina‐β‐diketones with Phosphines: Diacetylplatinum(II) Complexes and Mononuclear Platina‐β‐diketones Addition of mono‐ and bidentate phosphines or of AsPh₃ to the platina‐β‐diketone [Pt₂{(COMe)₂H}₂(μ‐Cl)₂] ( 1 ) followed by the addition of NaOMe at ?70 °C resulted in the formation of diacetyl platinum(II) complexes cis‐[Pt(COMe)₂L₂] (L = PPh₃, 2a ; P(4‐FC₆H₄)₃, 2b ; PPh₂(4‐py), 2c ; PMePh₂, 2d ; AsPh₃, 2d ) and [Pt(COMe)₂(L??L)] (L??L = dppe, 3b ; dppp, 3c ), respectively. The analogous reaction with dppm afforded the dinuclear complex cis‐[{Pt(COMe)₂}₂(μ‐dppm)₂] ( 4 ) that reacted in boiling acetone yielding [Pt(COMe)₂(dppm)] ( 3a ). The reactions 1 → 2 / 3 were found to proceed via thermally highly unstable cationic mononuclear platina‐β‐diketone intermediates [Pt{(COMe)₂H}L₂]⁺ and [Pt{(COMe)₂H}(L??L)]⁺, respectively, that could be isolated as chlorides for L??L = dppe ( 5a ) and dppp ( 5b ). The reversibility of the deprotonation of type 5 complexes with NaOMe yielding type 3 complexes was shown by the protonation of the diacetyl complex 3b with HBF₄ yielding the platina‐β‐diketone [Pt{(COMe)₂H}(dppe)](BF₄) ( 5c ). All compounds were fully characterized by means of NMR and IR spectroscopies, and microanalyses. X‐ray diffraction analysis was performed for the complex cis‐[Pt(COMe)₂(PPh₃)₂]·H₂O·CHCl₃ ( 2a ·H₂O·CHCl₃).     

Synthesen und Strukturen von Bis(4,4′‐t‐butyl‐2,2′‐bipyridin)‐Ruthenium(II)‐Komplexen mit funktionellen Derivaten des Tetramethyl‐bibenzimidazols

Syntheses and Structures of Bis(4,4′‐t‐butyl‐2,2′‐bipyridine) Ruthenium(II) Complexes with functional Derivatives of Tetramethyl‐bibenzimidazole [(tbbpy)₂RuCl₂] reacts with dinitro‐tetramethylbibenzimidazole ( A ) in DMF to form the complex [(tbbpy)₂Ru( A )](PF₆)₂ ( 1a ) (tbbpy: bis(4,4′‐t‐butyl)‐2,2′bipyridine). Exchange of the two PF₆^? anions by a mixture of tetrafluor‐terephthalat/tetrafluor‐terephthalic acid results in the formation of 1b in which an extended hydrogen‐bonded network is formed. According to the ¹H NMR spectra and X‐ray analyses of both 1a and 1b , the two nitro groups of the bibenzimidazole ligand are situated at the periphery of the complex in cis position to each other. Reduction of the nitro groups in 1a with SnCl₂/HCl results in the corresponding diamino complex 2 which is a useful starting product for further functionalization reactions. Substitution of the two amino groups in 2 by bromide or iodide via Sandmeyer reaction results in the crystalline complexes [(tbbpy)₂Ru( C )](PF₆)₂ and [(tbbpy)₂Ru( D )](PF₆)₂ ( C : dibromo‐tetrabibenzimidazole, D : diiodo‐tetrabibenzimidazole). Furthermore, 2 readily reacts with 4‐t‐butyl‐salicylaldehyde or pyridine‐2‐carbaldehyde under formation of the corresponding Schiff base Ru^II complexes 5 and 6 . ¹H NMR spectra show that the substituents (NH₂, Br, I, azomethines) in 2 ‐ 6 are also situated in peripheral positions, cis to each other. The solid state structure of both 2 , and 3 , determined by X‐ray analyses confirm this structure. In addition, the X‐ray diffraction analyses of single crystals of the complexes [(tri‐t‐butyl‐terpy)(Cl)Ru( A )] ( 7 ) and [( A )PtCl₂] ( 8 ) display also that the nitro groups in these complexes are in a cis‐arrangement.     

Luminescent Platinum(II) Complexes of 1,3‐Bis(N‐alkylbenzimidazol‐ 2′‐yl)benzene‐Type Ligands with Potential Applications in Efficient Organic Light‐Emitting Diodes

A series of luminescent platinum(II) complexes of tridentate 1,3‐bis(N‐alkylbenzimidazol‐2′‐yl)benzene (bzimb) ligands has been synthesized and characterized. One of these platinum(II) complexes has been structurally characterized by X‐ray crystallography. Their electrochemical, electronic absorption, and luminescence properties have been investigated. Computational studies have been performed on this class of complexes to elucidate the origin of their photophysical properties. Some of these complexes have been utilized in the fabrication of organic light‐emitting diodes (OLEDs) by using either vapor deposition or spin‐coating techniques. Chloroplatinum(II)? bzimb complexes that are functionalized at the 5‐position of the aryl ring, [Pt(R‐bzimb)Cl], not only show tunable emission color but also exhibit high current and external quantum efficiencies in OLEDs. Concentration‐dependent dual‐emissive behavior was observed in multilayer OLEDs upon the incorporation of pyrenyl ligand into the Pt(bzimb) system. Devices doped with low concentrations of the complexes gave rise to white‐light emission, thereby representing a unique class of small‐molecule, platinum(II)‐based white OLEDs.     

Diselenastanna‐, ‐sila‐ and ‐carbacycles with an annelated dicarba‐closo‐dodecaborane(12) unit

The reactions of the 1,2‐diselenolato‐1,2‐dicarba‐closo‐dodecaborane(12) dianion 1 with diorganoelement(IV) dichlorides (Ph₂CCl₂, Me₂SiCl₂, Ph₂SiCl₂, Me₂SnCl₂, Ph₂SnCl₂) gave novel five‐member heterocycles along with other products. The molecular structures of the five‐member rings containing CPh₂ ( 2 ) and SnPh₂ ( 9 ) moieties between the selenium atoms were determined by X‐ray analyses. In the case of the chlorosilanes, the analogous five‐member ring containing the SiPh₂ unit ( 4 ) could be identified in mixtures. The expected reaction was accompanied by rearrangement leading to formation of another five‐member ring 6 containing the Ph₂Si? Se? Se moiety. Oxidative addition of the five‐member heterocycles containing tin ( 7, 9 ) to ethene‐bis(triphenylphosphane)platinum(0) gave at low temperature the bis(triphenylphosphane)platinum(II) complexes 12 and 13 , where the Pt(PPh₃)₂ fragment had been inserted into one of the Sn? Se bonds. Extensive decomposition of these complexes was observed above ? 20 °C. The proposed solution‐state structures of the new compounds are supported by multinuclear magnetic resonance data (¹H, ¹¹B, ¹³C, ²⁹Si, ³¹P, ⁷⁷Se, ¹¹⁹Sn and ¹⁹⁵Pt NMR). Copyright © 2007 John Wiley & Sons, Ltd.     

In situ synthesis of mononuclear copper(II) complexes of the new tridentate ligand bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine

Two mononuclear copper complexes, {bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl‐κN²)methyl]amine‐κN}(3,5‐dimethyl‐1H‐pyrazole‐κN²)(perchlorato‐κO)copper(II) perchlorate, [Cu(ClO₄)(C₅H₈N₂)(C₁₂H₁₉N₅)]ClO₄, (I), and {bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl‐κN²)methyl]amine‐κN}bis(3,5‐dimethyl‐1H‐pyrazole‐κN²)copper(II) bis(hexafluoridophosphate), [Cu(C₅H₈N₂)₂(C₁₂H₁₉N₅)](PF₆)₂, (II), have been synthesized by the reactions of different copper salts with the tripodal ligand tris[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine (TDPA) in acetone–water solutions at room temperature. Single‐crystal X‐ray diffraction analysis revealed that they contain the new tridentate ligand bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine (BDPA), which cannot be obtained by normal organic reactions and has thus been captured in the solid state by in situ synthesis. The coordination of the Cu^II ion is distorted square pyramidal in (I) and distorted trigonal bipyramidal in (II). The new in situ generated tridentate BDPA ligand can act as a meridional or facial ligand during the process of coordination. The crystal structures of these two compounds are stabilized by classical hydrogen bonding as well as intricate nonclassical hydrogen‐bond interactions.     

Pseudohalide‐directed Assembly of Two Zinc(II) Coordination Polymers with a 3,4‐Bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole Tecton

The zinc(II) pseudohalide complexes {[Zn(L³³⁴)(SCN)₂(H₂O)](H₂O)₂}_n ( 1 ) and [Zn(L³³⁴)(dca)₂]_n ( 2 ) were synthesized and characterized using the ligand 3,4‐bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole (L³³⁴) and ZnCl₂ in presence of thiocyanate (SCN^–) and dicynamide [dca, N(CN)₂^–] respectively. Single‐crystal X‐ray structural analysis revealed that the central Zn^II atoms in both complexes have similar octahedral arrangement. Compound 1 has a 2D sheet structure bridged by bidentate L³³⁴ and double μ_N,S‐thiocyanate anions, whereas complex 2 , incorporating with two monodentate dicynamide anions, displays a two‐dimensional coordination framework bridged by tetradentate L³³⁴ ligand. Structural analysis demonstrated that the influence of pseudohalide anions plays an important role in determining the resultant structure. Both complexes were characterized by IR spectroscopy, microanalysis, and powder X‐ray diffraction techniques. In addition, the solid fluorescence and thermal stability properties of both complexes were investigated.     

Sulfur‐Assisted Intermolecular Triphenylphosphine Dissociation of Thiocarbamoyl Ligand in Platinum(II). X‐ray Structure of Complex [Pt(PPh3)2(η1‐SCNMe2)(Cl)]

Treatment of Pt(PPh₃)₄ with N,N‐dimethylthiocarbamoyl chloride, Me₂NC(=S)Cl, in dichloromethane at ?20 °C processes the oxidative addition reaction to produce platinum complex [Pt(PPh₃)₂(η¹‐SCNMe₂)(Cl)], 2 with releasing two triphenylphosphine molecules. The ³¹P{¹H} NMR spectra of complex 2 shows the dissociation of the triphenylphosphine ligand to form diplatinum complex [Pt(PPh₃)Cl]₂(μ,η²‐SCNMe₂)₂, 3 in which the two SCNMe₂ ligands coordinated through carbon to one metal center and bridging the other metal through sulfur. Complex 2 is characterized by X‐ray diffraction analysis.     

Synthesis,Crystal Structure and Spectroscopic Properties of [2,13‐Bis(1‐naphthalenylmethyl)‐5,16‐dimethyl‐2,6,13,17‐tetraazatricyclo(14,4,01.18,07.12)docosane]copper(II) Diperchlorate Acetonitrile Disolvate

The N‐functionalized macrocyclic ligand 2,13‐bis(1‐naphthalenylmethyl)‐5,16‐dimethyl‐2,6,13,17‐tetraazatricyclo(14,4,0^1.18,0^7.12)docosane (L³) and its copper(II) complex were prepared. The crystal structure of [Cu(L³)](ClO₄)₂·2CH₃CN was determined by single‐crystal X‐ray diffraction at 150 K. The copper atom, which lies on an inversion centre, has a square planar arrangement and the complex adopts a stable trans‐III configuration. The longer distance [2.081(2) Å] for Cu–N(tertiary) compared to 2.030(3) Å for Cu–N(secondary) may be due to the steric effect of the attached naphthalenylmethyl group on the tertiary nitrogen atom. Two perchlorate ions are weakly attached to copper in axial sites and are further connected to the ligand of the cation through NH ··· O hydrogen bonds [N ··· O 3.098 Å]. IR and UV/Vis spectroscopic properties are also described.     

Di­chloro­(norborna­diene)­platinum(II): a comparison with di­chloro­(cyclo­octa­diene)­platinum(II)

The crystal structure of the title compound, (bi­cyclo­[2.2.1]­hepta‐2,5‐diene)­di­chloro­platinum(II), [PtCl₂(C₇H₈)], has been determined from single‐crystal X‐ray analysis. The coordination sphere about the Pt atom is pseudo‐square planar, with shorter Pt—C distances than in the corresponding di­chloro­(cyclo­octa­diene)­platinum(II) complex.     

A two‐dimensional copper(II) coordination polymer based on 2,4′‐oxybis(benzoate) and 4,4′‐bipyridine

The reaction of Cu(NO₃)₂·3H₂O with 2,4′‐oxybis(benzoic acid) and 4,4′‐bipyridine under hydrothermal conditions produced a new mixed‐ligand two‐dimensional copper(II) coordination polymer, namely poly[[(μ‐4,4′‐bipyridine‐κ²N ,N ′)[μ‐2,4′‐oxybis(benzoato)‐κ⁴O ²,O ^2′:O ⁴,O ^4′]copper(II)] monohydrate], {[Cu(C₁₄H₈O₅)(C₁₀H₈N₂)]·H₂O}_n , which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction. The X‐ray diffraction crystal structure analysis reveals that the Cu^II ions are connected to form a two‐dimensional wave‐like network through 4,4′‐bipyridine and 2,4′‐oxybis(benzoate) ligands. The two‐dimensional layers are expanded into a three‐dimensional supramolecular structure through intermolecular O—H…O and C—H…O hydrogen bonds. Furthermore, magnetic susceptibility measurements indicate that the complex shows weak antiferromagnetic interactions between adjacent Cu^II ions.