Transition metal complexes with the thiosemicarbazide-based ligands. Part 12. Synthesis,structure and template reaction of ammine [2,4-pentane-dione S-methylisothiosemicarbazonato(2-)] nickel(II) dihydrate

Summary Ni(NO₃)₂·6H₂O reacts with 2,4-pentanedione S-methylisothiosemicarbazonehydrogen iodide (H₂L·HI) in aqueous solution; addition of ammonia then yields [NiL(NH₃)]·2H₂O, the crystal structure of which has been determined. In the square-planar [NiL(NH₃)]·2H₂O complex, the ligand, 2,4-pentanedione S-methylisothio-semicarbazone occupies three coordination sites with the bonds to the central atoms involving the terminal nitrogen atoms of the isothiosemicarbazide fragment [Ni–N(3) 1.831 Å and Ni–N(2) 1.842 Å] and the oxygen of the 2,4-pentanedione moiety [Ni–O 1.844 Å]. The template reaction of [NiL(NH₃)]·2H₂O with 2,4-pentanedione and triethyl orthoformate, HC(OEt)₃, gave, by heating the complexes, NiL¹ (1) (L¹ = dianion of the quadridentate NNNN macrocyclic ligand 2,10-bis(methylthio)-5,7,12,14-tetramethyl-1,3,4,8,9,11 -hexaazacyclotetradeca-2,4,6,9,12,-14-hexaene) and NiL² (2) (L² = dianion of the quadridentate ONNO ligand 3-acetyl-6-thiomethyl-9-methyl-5,7,8-tri-azadodeca-3,6,9-triene-2,11-dione) presents described.     

Dinuclear rhenium(I) carbonyl complexes based on π-conjugated polypyridyl ligands with tetrathiafulvalenes: Syntheses, crystal structures, properties and DFT calculations

A series of tetrathiafulvalene-substituted 2,3-di(2-pyridyl)quinoxaline (dpq) ligands, 2-(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)-6,7-di(pyridin-2-yl)- [1,3]dithiolo[4,5-g]quinoxaline (L₁), dimethyl-2-(6,7-di(pyridin-2-yl)-[1,3]dithiolo[4,5-g]quinoxalin-2-ylidene)-1,3-dithiole-4,5-dicarboxylate (L₂), and 2-(5,6-dihydro-[1,3]dithiolo[4,5-b] [1,4]dithiin-2-ylidene)-6,7-di(pyridin-2-yl)-[1,3]dithiolo[4,5-g]quinoxaline (L₃), have been prepared. Reactions of these ligands with Re(CO)₅Cl afford the corresponding dinuclear rhenium(I) carbonyl complexes, Re₂(L)(CO)₆Cl₂ (L = L₁, 5a; L = L₂, 5b; L = L₃, 5c). All new compounds are fully characterized by ¹H NMR, IR and mass spectroscopies. The crystal structures of 5a and 5b have been studied. Optimized conformations and molecular orbital diagrams of 5a−5c have been calculated with density functional theory (DFT). The spin-allowed singlet−singlet electronic transitions of all complexes have been calculated with time-dependent DFT (TDDFT), and the UV-Vis−NIR spectra are discussed based on the theoretical calculations.     

Synthesis,characterization, and antibacterial activity of two zinc(II) complexes with Schiff bases derived from rimantadine

The reactions of zinc(II) chloride and two Schiff base ligands derived from rimantadine and 5-chlorosalicylaldehyde/4-methoxysalicylaldehydes, generated two novel complexes [Zn(L¹)₂Cl₂] (I) and [Zn(L²)₂Cl₂] (II), where L¹ = 2-((1-(1-adamantan-1-yl)ethyl)-iminomethyl)-4-chlorophenol, L² = 2-((1-(1-adamantan-1-yl)ethyl)iminomethyl)-5-methoxyphenol. The complexes were characterized by the means of IR, ¹H NMR, elemental analysis, molar conductance and thermal analysis. A single-crystal X-ray diffraction analysis reveals that both complexes crystallize in orthorhombic system, space group Fdd2 for I and Pbcn for II. In two complexes crystals, each asymmetric unit consists of one zinc(II) ion, two corresponding Schiff base ligands and two chlorine atoms; the central zinc atom lies on a twofold rotation axis and is four-coordinate via two chlorine atoms and two oxygen atoms from the Schiff base ligands, forming a distorted tetrahedral geometry.     

Crystal structures and enhanced luminescence of Zn(II) and Cd(II) complexes containing conjugated organic ligands

By self-assembly of delocalized organic ligands (L¹ and L²) with Cd(SCN)₂, ZnI₂ and Zn(NCS)₂, three luminescent complexes ZnI₂(L¹)₂ (I), [Cd(L¹)₂(μ_1,3-SCN)₂] _n (II) and Zn(NCS)₂(L²)₂ (III) were obtained (L¹ = 2-{5,5-dimethyl-3-[2-(pyridine-4-yl)ethenyl]cyclohex-2-enylidene}propanedinitrile and L² = 2-{5,5-dimethyl-3-[2-(pyridine-3-yl)ethenyl]cyclohex-2-enylidene}propanedinitrile). The structures of the complexes were determined by single crystal X-ray diffraction analysis (CIF files CCDC nos. 1406116 (I), 1406115 (II), and 1400360 (III)). In complex I, Zn(II) is coordinated by two functional organic ligands and two I^– ions, to form a I₂N₂ distorted tetrahedral geometry. In 1D coordination polymer II, the Cd(II) centers show six-coordinated geometries, two organic ligands and four SCN^– ions involve in coordination with each Cd(II) center. The thiocyanate groups show μ_1,3-SCN bridging coordination modes and the adjacent Cd(II) ions are bridged by double μ_1,3-SCN ions to form an infinite chain. In complex III, Zn(II) is coordinated by two functional organic ligands and two NCS^– groups, to form a N₄ distorted tetrahedral geometry. Compared with the free ligands, the complexes show superior luminescent property with red-shift and enhancement of fluorescence intensity.     

Specifics of luminescence of (benzoxazolyl)phenolate and (benzothiazolyl)naphtholate heterometallic Zn,Sc, Nd,Sm, Er,and Yb complexes

Heterometallic complexes Ln(L¹)₅Zn (Ln = Sc, Sm, Gd) were obtained by the reactions of silylamides Ln[N(SiMe)₂]₃ with 2-(benzoxazol-2-yl)phenol (HL¹) in the presence of diethylzinc. Similar reactions with 3-(benzothiazol-2-yl)-2-naphthol (HL²) led to the formation of complexes Ln(L²)₅Zn (Ln = Nd, Er, Gd, Yb). The introduction of the zinc-containing fragments provided a considerable increase of photo- and electroluminescence intensity of the scandium complex.     

Reactivity of bis(pyrazol-1-yl)methanes functionalized by 2-hydroxyphenyl and 2-methoxyphenyl on the methine carbon atom with W(CO)5THF

Reactions of 2-hydroxyphenyl and 2-methoxyphenylbis(pyrazol-1-yl)methanes as well as 2-hydroxyphenyl and 2-methoxyphenylbis(3,5-dimethylpyrazol-1-yl)methanes with W(CO)₅THF have been carried out. Heating 2-hydroxyphenylbis(pyrazol-1-yl)methane (L¹) with W(CO)₅THF in THF at reflux yielded complex (L¹)W(CO)₄.L¹, while similar reaction of 2-hydroxyphenylbis(3,5-dimethylpyrazol-1-yl)methane (L²) with W(CO)₅THF resulted in the cleavage of a C_sp3-N bond to generate 1,2-bis(2-hydroxyphenyl)-1,2-bis(3,5-dimethylpyrazol-1-yl)ethane (L) and pyrazole derivative W(CO)₅(3,5-Me₂PzH) (Pz = pyrazol-1-yl). These two fragments were connected together through strong O…H-N and O-H…N hydrogen bonds to form complex L.[W(CO)₅(3,5-Me₂PzH)]₂. The analogous results were observed in the treatment of 2-methoxyphenylbis(pyrazol-1-yl)methane (L³) with W(CO)₅THF, which gave product L′.[W(CO)₅(PzH)]₂ (L′ = 1,2-bis(2-methoxyphenyl)-1,2-bis(pyrazol-1-yl)ethane) as well as certain amount of complex (L³)W(CO)₄. In addition, during the reaction of 2-methoxyphenylbis(3,5-dimethylpyrazol-1-yl)methane (L⁴) with W(CO)₅THF, partial decomposition reactions took place to yield complexes (L⁴)W(CO)₄ and W(CO)₅(3,5-Me₂PzH), but no hydrogen bond was found between these two moieties.     

Synthesis,spectroscopic, thermal,and antimicrobial studies of tetradentate 12 and 14 member Schiff bases and their complexes with Fe(III), Co(II), and Cu(II)

Two Schiff bases, L¹ (5,6;11,12-dibenzophenone-2,3,8,9-tetramethyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene) and L² (6,7;13,14-dibenzophenone-2,4,9,11-tetramethyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene), bearing functionalized pendant arms have been synthesized by cyclocondensation of 3,4-diaminobenzophenone with 2,3-butanedione and 2,4-pentanedione, respectively. Mononuclear macrocyclic complexes [FeL¹Cl₂]Cl, [FeL²Cl₂]Cl, [ML¹Cl₂], and [ML²Cl₂] (where M?=?Co(II) and Cu(II)) have been prepared by reacting iron(III), cobalt(II), and copper(II) with the preformed Schiff base. The ligands and their corresponding metal complexes were characterized by elemental analyses, ESI-mass spectra, conductivity, magnetic moments, UV-Vis, EPR, IR, ¹H-, and ¹³C-NMR spectral studies, and TGA-DTA/DSC data. The TGA profiles exhibit a two-step pyrolysis, although the iron complexes decompose in three steps, leaving behind metal oxides as the final product. The ligands and complexes were screened in vitro against Gram-positive bacteria, Gram-negative bacteria, and fungi.     

Zn(II) Complexes with Quinoline Supported Amidate Ligands: Synthesis,Fluorescence, and Catalytic Activity

Zn(II) complexes of N-(quinolin-8-yl)picolinamide (HL¹) (1) and N²,N⁶-di(quinolin-8-yl)pyridine-2,6-dicarboxamide (H₂L²) (2) have been synthesized by deprotonation of the ligands and characterized by IR, NMR, and Single crystal X-ray crystallography. The mononuclear [Zn(L¹)₂] (3) and homodinuclear [Zn₂(L²)₂] (4) complexes are characterized by distorted octahedral geometries stabilized by hydrogen bonding and weak π···π interaction. The complexes demonstrate intense fluorescence bands in comparison with their corresponding ligands with well-distinguished intensity. The complexes act as efficient catalysts in various transesterification reactions. Among those, the best results have been achieved with complex 3 in conversion of 4-nitrophenylacetate into methyl acetate within 3 h.

     

Multi-site coordination of ferrocenylamido-naphthyridine conjugates [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene and 1,1′-bis[{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene

Ferrocenylamido-naphthyridine conjugates [{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L¹) and 1,1′-bis[{(5,7-dimethyl-1,8-naphthyridin-2-yl)amino}carbonyl]ferrocene (L²) have been synthesized. Reaction of L¹ with [Cu(CH₃CN)₆][ClO₄]₂ affords [Cu(L¹)₂][ClO₄]₂ (1) demonstrating tridentate coordination of the ligand utilizing naphthyridine (NP) nitrogens and carbonyl oxygen. Hydroxo-bridged neutral dirhenium(I) compound [K⊂{{Re(CO)₃}₂(μ-OH)(Fc(CONHNP)(CO NP))₂}] (2) is reported in which the amido-NP arm of L² chelates a Re^I, and a K⁺ ion is encapsulated in a six-coordinate environment rendered by four NP nitrogens and two carbonyl oxygens involving all four arms of two L² ligands. Selective and reversible binding of K⁺ ion by the organometallic host has been recognized from electrochemical and fluorescence experiments. Partial hydrolysis of L² has provided a neutral metallamacrocycle [{Re(CO)₃}₂{Fc(CO₂)(CONHNP)}₂] (3) consisting of alternate Fc and Re(CO)₃ units linked by carboxylate and amide-NP bridges. The rotational freedom of the ferrocenyl rings, the flexibility of the amide linker and the multi-site coordination of the ligands are demonstrated in the molecular structures of compounds 1-3.     

Sulfanylamide-containing coordination compounds of 3d-elements with 2,4-pentanedione bis-thiosemicarbazone and bis-4-phenylthiosemicarbazone

Thiosemicarbazide and 4-phenylthiosemicarbazide react in ethanol with 2,4-pentanedione in the presence of manganese, cobalt, nickel, copper, and zinc acetates hydrates and streptamin (Sf¹), sulfaethidole (Sf²), and sulfadimidine (Sf³) to form coordination compounds of the composition M(Sf^1–3)(L^1–2) · nH₂O (M = Mn, Co, Ni, Cu, Zn; H₂L¹ is 2,4-pentanedione bis-thiosemicarbazone, H₂L² is 2,4-pentanedione bis-4-phenylthiosemicarbazone; n = 0–6). All the complexes synthesized are monomeric. Thiosemicarbazones (H₂L¹ and H₂L²) behave as twice deprotonated S,N,N,S-tetradentate ligands, while sulfanylamides (Sf^1–3) act as monodentate ones. Thermolysis of these substances proceeds through the stages of dehydration (65–95°C) and complete thermal decomposition (430–560°C). It is found that the complex [Cu(Sf²)(L¹)] · 4H₂O in the concentration 10^?5 M inhibits the growth and fission of 100% cancer cells of the human myeloid leukemia (HL-60).     

NNS tridentate thiosemicarbazide and 1,3,4-thiadiazole-2-amine complexes of some transition metal ions: syntheses,structure and fluorescence properties

The reactions of Zn(II), Mn(II), and Ni(II) acetates with 1-picolinoyl-4-phenyl-3-thiosemicarbazide (Hppts) yielded [Zn(ppts)₂]·CHCl₃ (3), [Mn(ppts)₂]·THF (4), and [Ni(ppts)₂]·THF (5), respectively, but HgCl₂ gave a cyclized product N-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole-2-yl-amine (2). The treatment of Hppts with conc. H₂SO₄ formed N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-yl-amine (1). Hppts is a nonfluorescent material, but 3, 4 and the cyclized products 1,3,4-oxadiazole/1,3,4-thiadiazole are fluorescent. The cyclized ligand N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-amine (1) formed [Zn(2-Hppt)₂(OAc)₂] (6) and [Cd₂(2-Hppt)₂(OAc)₂(μ-OAc)₂] (7) in which Cd(II) has a binuclear acetate-bridged seven coordinate pentagonal bipyramidal geometry. Complex 7 is also a fluorescent material with maximum emission at 425 nm at an excitation wavelength of 254 nm.     

Synthesis, crystal structures, electrochemical and spectroscopic properties of ruthenium(II) complexes containing diamino-1,3,5-triazine derivatives

Three Ru(II) complexes [Ru(bpy)₂(1-IQTNH)](ClO₄)₂ (1), [Ru(bpy)₂(2-QTNH)](ClO₄)₂ (2) and [Ru(bpy)₂(3-IQTNH)](ClO₄)₂ (3) (bpy = 2,2′-bipyridine, 1-IQTNH = 6-(isoquinolin-1-yl)-1,3,5-triazine- 2,4-diamine, 2-QTNH = 6-(quinolin-2-yl)-1,3,5-triazine- 2,4-diamine, 3-IQTNH = 6-(isoquinolin-3-yl)-1,3,5-triazine-2,4-diamine) have been synthesized and characterized by elemental analysis, ¹H NMR spectroscopy, electrospray ionization mass spectrometry and X-ray crystallography. The electrochemical and spectroscopic properties of the complexes differ from those of [Ru(bpy)₃]²⁺ owing to the structural differences between the ligands and their complexes.     

Synthesis and characterization of new sulfide aggregates of the type [{Pt2(μ3-S)2(P-P)2}M(C6F5)2] (M=Ni, Pd, Pt; P-P=2PPh3, 2PMe2Ph, dppf)

The reaction of [Pt₂(μ-S)₂(P-P)₂] (P-P=2PPh₃, 2PMe₂Ph, dppf) [dppf=1,1^′-bis(diphenylphosphino)ferrocene] with cis-[M(C₆F₅)₂(PhCN)₂] (M=Ni, Pd) or cis-[Pt(C₆F₅)₂(THF)₂] (THF=tetrahydrofuran) afforded sulfide aggregates of the type [{Pt₂(μ₃-S)₂(P-P)₂}M(C₆F₅)₂] (M=Ni, Pd, Pt). X-ray crystal analysis revealed that [{Pt₂(μ₃-S)₂(dppf)₂}Pd(C₆F₅)₂], [{Pt₂(μ₃-S)₂(PPh₃)₂}Ni(C₆F₅)₂], [{Pt₂(μ₃-S)₂(PPh₃)₂}Pd(C₆F₅)₂] and [{Pt₂(μ₃-S)₂(PMe₂Ph)₂}Pt(C₆F₅)₂] have triangular M₃S₂ core structures capped on both sides by μ₃-sulfido ligands. The structural features of these polymetallic complexes are described. Some of them display short metal-metal contacts.     

Tetranuclear Zn(II) and Mononuclear Nickel(II) Complexes Based on Asymmetric Salamo-Type Ligands: Syntheses,Crystal Structures,and Fluorescent Properties

Two new complexes [{Zn(L¹)(μ-OAc)Zn(CH₃CHOHCH₃)}₂] and [Ni(L₂)(H₂O)(CH₃OH)] with asymmetric Salamo-type ligands (H₃L¹ and H₂L²) are synthesized and structurally characterized. In the Zn(II) and Ni(II) complexes, the terminal and central Zn(II) atoms are found to have slightly distorted square pyramidal and trigonal bipyramidal symmetries respectively, while the Ni(II) atom is hexa-coordinated and has a slightly distorted octahedral symmetry. Interestingly, a self-assembling continual zigzag 1D chain is formed by intermolecular hydrogen bonds in the Ni(II) complex. Furthermore, the Zn(II) and Ni(II) complexes in the ethanol solution show intense photoluminescence.     

Ruthenium piano-stool complexes bearing imidazole-based PN ligands

A variety of piano-stool complexes of cyclopentadienyl ruthenium(II) with imidazole-based PN ligands have been synthesized starting from the precursor complexes [CpRu(C₁₀H₈)]PF₆, [CpRu(NCMe)₃]PF₆ and [CpRu(PPh₃)₂Cl]. PN ligands used are imidazol-2-yl, -4-yl and -5-yl phosphines.Depending on the ligand and precursor different types of coordination modes were observed; in the case of polyimidazolyl PN ligands these were κ¹P-monodentate, κ²P,N-, κ²N,N- and κ³N,N,N- chelating and μ-κP:κ²N,N-brigding. The solid-state structures of [CpRu(1a)₂Cl ]·H₂O (5^.H₂O) and [{CpRu(μ-κ²-N,N-κ’¹-P-2b)}₂](C₆H₅PO₃H)₂(C₆H₅PO₃H₂)_2, a hydrolysis product of the as well determined [{CpRu(2b)}₂](PF₆)₂^.2CH₃CN (7b^.2CH₃CN) were determined (1a = imidazol-2-yldiphenyl phosphine, 2b = bis(1-methylimidazol-2-yl)phenyl phosphine, 3a = tris(imidazol-2-yl)phosphine). Furthermore, the complexes [CpRu(L)₂]PF₆ (L = imidazol-2-yl or imidazol-4-yl phosphine) have been screened for their catalytic activity in the hydration of 1-octyne.     

Neue metallorganisch substituierte Indium–Stickstoff-Verbindungen. Synthese und Kristallstrukturen von [{Cp(CO)3Mo}2InN(SiMe3)2] und [{Cp(CO)3Mo}In{N(SiMe3)2}2]

New Organometallic Indium Nitrogen Compounds. Synthesis and Crystal Structures of [{Cp(CO)₃Mo}₂InN(SiMe₃)₂] and [{Cp(CO)₃Mo}In{N(SiMe₃)₂}₂] The reaction of [{Cp(CO)₃Mo}₂InCl] with LiN · (SiMe₃)₂ leads to the formation of [{Cp(CO)₃Mo}₂InN · (SiMe₃)₂] ( 1 ). 1 is monomeric and it contains an indium atom which is coordinated in a trigonal planar manner by two {Cp(CO)₃Mo} fragments and a N(SiMe₃)₂ group. The corresponding bis-amide [{Cp(CO)₃Mo}In{N(SiMe₃)₂}₂] ( 2 ) is prepared by the reaction of [{Cp(CO)₃Mo}InCl₂] with two equivalents of LiN(SiMe₃)₂. In analogy to 1, 2 is monomeric and it contains an indium atom in a trigonal planar coordination.     

Syntheses,crystal structures and magnetic properties of three new binuclear Ni(II) complexes derived from tripodal tetradentate (N4) ligands

Three new binuclear Ni(II) complexes [{Ni(L_22py)Cl}₂](ClO₄)₂ (1), [{Ni(L_23py)Cl}₂](ClO₄)₂ (2), and [{Ni(L_33py)Cl}₂](ClO₄)₂ (3), {L_22py = N-(2-pyridylmethyl)-N-(2-aminoethyl)-1,2-diaminoethane, L_23py = N-(2-pyridylmethyl)-N-(2-aminoethyl)-1,3-diaminopropane, L_33py = N-(2-pyridylmethyl)-N-(3-aminopropyl)-1,3-diaminopropane} have been synthesized. Single crystal X-ray structure analysis showed that in each complex two distorted octahedral Ni(II) ions are bridged asymmetrically by a pair of chloride anions. Variable temperature magnetic susceptibility measurements of 1 and 3 revealed dominant ferromagnetic exchange interactions.     

Discrete Cationic Zinc and Magnesium Complexes for Dual Organic/Organometallic‐Catalyzed Ring‐Opening Polymerization of Trimethylene Carbonate

We describe herein an original approach for the efficient immortal ring‐opening polymerization (iROP) of trimethylene carbonate (TMC) under mild conditions using dual‐catalyst systems combining a discrete cationic metal complex with a tertiary amine. A series of new zinc and magnesium cationic complexes of the type [{NNO}M]⁺[anion]^? ({NNO}^?=2,4‐di‐tert‐butyl‐6‐{[(2′‐dimethylaminoethyl)methylamino]methyl}phenolate; M=Zn, [anion]^?=[B(C₆F₅)₄]^? ( 2 ), [H₂N‐ {B(C₆F₅)₃}₂]^? ( 3 ), and [EtB(C₆F₅)₃]^? ( 4 ); M=Mg, [anion]^?=[H₂N{B(C₆F₅)₃}₂]^? ( 7 )) have been prepared from the corresponding neutral compounds [{NNO}ZnEt] ( 1 ) and [{NNO}‐ Mg(nBu)] ( 6 ). Compounds 2 – 4 and 7 exist as free ion pairs, as revealed by ¹H, ¹³C, ¹⁹F, and ¹¹B NMR spectroscopy in THF solution, and an X‐ray crystallographic analysis of the bis(THF) adduct of compound 7 , 7? (THF)₂. The neutral complexes 1 and 6 , in combination with one equivalent or an excess of benzyl alcohol (BnOH), initiate the rapid iROP of TMC, in bulk or in toluene solution, at 45–60 °C (turnover frequency, TOF, up to 25–30 000 mol(TMC)?mol(Zn)?h^?1 for 1 and 220–240 000 mol(TMC)?mol(Mg)?h^?1 for 6 ), to afford H‐PTMC‐OBn with controlled macromolecular features. ROP reactions mediated by the cationic systems 2 /BnOH and 7 /BnOH proceeded much more slowly (TOF up to 500 and 3 000 mol(TMC)?mol(Zn or Mg)?h^?1 at 110 °C) than those based on the parent neutral compounds 1 /BnOH and 6 /BnOH, respectively. Use of original dual organic/organometallic catalyst systems, obtained by adding 0.2–5 equiv of a tertiary amine such as NEt₃ to zinc cationic complexes [{NNO}Zn]⁺[anion]^? ( 2 – 4 ), promoted high activities (TOF up to 18 300 mol(TMC)?mol(Zn)?h^?1 at 45 °C) giving H‐PTMC‐OBn with good control over the M_n and M_w/M_n values. Variation of the nature of the anion in 2 – 4 did not significantly affect the performance of these catalyst systems. On the other hand, the dual magnesium‐based catalyst system 7 /NEt₃ proved to be poorly effective.     

Synthesis,Structures, Magnetic and Luminescent Properties of a Series of Iron(II) and Zinc(II) Coordination Frameworks with Versatile 4‐Substitued 1, 2,4‐Triazole Ligands

Three multi‐dentate 1, 2,4‐triazole derivative ligands containing different 4‐substituted groups, namely N‐1, 2,4‐triazol‐4‐yl(pyridin‐3‐yl)methylenimine (L₁), N‐1, 2,4‐triazol‐ 4‐yl(pyridin‐4‐yl)methylenimine (L₂), and 4‐(2‐pyridine)‐1, 2,4‐triazole (L₃) were used to isolate five iron(II) and zinc(II) coordination frameworks, [Zn(μ₂‐L₁)Cl₂] ( 1 ), [Zn(μ₂‐L₂)Br₂] ( 2 ), [Fe(L₁)₂(NCS)₂(H₂O)₂] ( 3 ), [Fe(L₃)₂(dca)₂(H₂O)₂] ( 4 ), and [Fe(L₃)₂(μ₂‐dca)] ( 5 ) (dca = dicyanamide anion). When different zinc(II) salts were used to react with L₁ and L₂ under solvothermal conditions, two one‐dimensional (1D) zinc(II) coordination frameworks 1 and 2 containing four‐coordinate central zinc(II) atoms were isolated. 1 is a 3D achiral supra‐molecular framework, whereas 2 is a 3D chiral supra‐molecular framework containing helical chains on a 2₁ axis. 3 is a mono‐nuclear iron(II) coordination framework containing six‐coordinate central Fe^II atoms. When L₃ was employed, mono‐nuclear iron(II) framework 4 and 1D iron(II) chain 5 could be isolated when different amounts of Nadca were introduced into the reaction system. Variable‐temperature magnetic susceptibility data of 3 – 5 were recorded in the 2–300 K temperature range indicating weak anti‐ferromagnetic interactions. The solid‐state luminescent properties of coordination polymers 1 and 2 were also investigated at room temperature.     

Bis(phosphinimino)methanides as ligands in divalent lanthanide and alkaline earth chemistry - synthesis, structure, and catalysis

Divalent bis(phosphinimino)methanide lanthanide complexes of composition [{(Me₃SiNPPh₂)₂CH}EuI(THF)]₂ and [{(Me₃SiNPPh₂)₂CH}YbI(THF)₂] have been prepared by a salt metathesis reactions of K{CH(PPh₂NSiMe₃)₂} and LnI₂. Further reactions of these complexes with [K(THF)_nN(PPh₂)₂] led selectively to the heteroleptic amido complexes [{(Me₃SiNPPh₂)₂CH}Ln{(Ph₂P)₂N}(THF)] (Ln = Eu, Yb). The ytterbium complex can also be obtained by reduction of [{CH(PPh₂NSiMe₃)₂}Yb{(Ph₂P)₂N}Cl] with elemental potassium. The single crystals of [{(Me₃SiNPPh₂)₂CH}Ln{(Ph₂P)₂N}(THF)] contain enantiomerically pure complexes. As a result of the similar ionic radii of the divalent lanthanides and the heavier alkaline earth metals some similarities in coordination chemistry of the bis(phosphinimino)methanide ligand were anticipated. Therefore, MI₂ (M = Ca, Sr, Ba) was reacted with K{CH(PPh₂NSiMe₃)₂} to give [{(Me₃SiNPPh₂)₂CH}CaI(THF)₂], [{(Me₃SiNPPh₂)₂CH}SrI(THF)]₂, and [{(Me₃SiNPPh₂)₂CH}BaI(THF)₂]₂, respectively. As expected the Sr and Eu complexes and the Ca and Yb complexes are very similar, whereas for the Ba compound, as a result of the large ion radius, a different coordination sphere is observed. For all new complexes the solid-state structures were established by single crystal X-ray diffraction. In the solid-state the {CH(PPh₂NSiMe₃)₂}⁻ ligand acts as tridentate donor forming a long methanide carbon metal bond. Thus, all complexes presented can be considered as organometallic compounds. [{(Me₃SiNPPh₂)₂CH}YbI(THF)₂] was also used as precatalyst for the intramolecular hydroamination/cyclization reaction of different aminoalkynes and aminoolefines. Good yields but moderate activities were observed.