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With the 30 years old first example of a stable group 4 metallocene bis(trimethylsilyl)acetylene (btmsa) complex Cp2Ti(η2‐btmsa) a series of similar complexes like Cp′2M(η2‐btmsa) (M = Ti, Zr; Cp′ = Cp, Cp* as η5‐pentamethylcyclopentadienyl and Cp′2 = rac‐(ebthi) as rac‐1,2‐ethylene‐1,1′‐bis(η5‐tetrahydroindenyl)) represent excellent sources for the generation of the very reactive coordinatively and electronically unsaturated complex fragments [Cp'2M], which were used in many synthetic and catalytic reactions. Examples for this were oresented in several papers and summarized in some reviews. In this update new reactions of group 4 metallocene bis(trimethylsilyl)acetylene complexes towards symmetrically and unsymmetrically α‐dihetero‐substituted alkynes, reactions with other alkynes, di‐ and polyynes to metallacyclopentadienes as well as the conversions of the formed products are summarized. Additionally, novel synthetic applications of the formed metallacyclopentadienes on the basis of the zirconocene bis(trimethylsilyl)acetylene complex Cp2Zr(py)(η2‐btmsa) are highlighted. Reactions with imines, neutral N‐donor ligands, E‐H compounds (E = N, O, P), molecular hydrogen, water, phosphino‐ and aminoboranes, E‐Cl compounds (E = C, P), disilylated germylenes and aryloxy ketones were described. Different self‐assembly reactions to multinuclear complexes by using group 4 metallocene bis(trimethylsilyl)acetylene complexes in C‐C coupling reactions with or without C‐H bond activation to tri‐ or tetranuclear complexes are considered, too. These examples are discussed following the general L‐M‐S principle for stoichiometric and catalytic reactions, whereby different ligands L (L = Cp′ = Cp, Cp*, rac‐ebthi), metals M (M = Ti, Zr, Hf) and substrate substituents S influence the reactivity and the obtained products. An old dog learns new tricks: Group 4 metallocene bis(trimethylsilyl)acetylene complexes Cp′2M(X)(η2‐btmsa) are excellent sources to generate the very reactive complex fragments [Cp'2M]. α‐Heterosubstituted alkynes, di‐ and polyynes, imines, N‐donors, E‐H‐ and E‐Cl‐compounds, hydrogen, water, phosphino‐ and aminoboranes, germylenes, aryloxy ketones, and N‐heterocycles gave many novel products. [ABSTRACT FROM AUTHOR]

This study identifies new phosphite-oxazoline ligands that have been successfully applied in the palladium-catalyzed intermolecular asymmetric Heck reaction. The design of the new phosphite-oxazoline ligands derives from a previous successful generation of phosphine-oxazoline ligands, by replacing the phosphine group with several π-acceptor biaryl phosphite moieties. With these simple modifications, the new phosphite-based ligands, unlike previous phosphine-oxazoline, not only present a modular design with numerous potential phosphite groups available, but they are also air-stable solids, which can be made in the same number of synthetic steps as the phosphine analogues. The substitution of the phosphine by a biaryl phosphite group extended the range of substrates and triflates sources that can be coupled with regio-, enantioselectivities and activities comparable to the few best ones reported. In addition, the ligands that provided the best selectivities contained an isopropyl oxazoline moiety instead of the tert-butyl group found in the related phosphine-oxazoline ligands, which is made from a much more expensive precursor. In this paper we have also carried out kinetic studies and a Hammett plot analysis to determine the rate determining step of this system in the regime of interest. We suggest a likely explanation for the fast Heck reaction of the phosphite-oxazoline catalysts. [ABSTRACT FROM AUTHOR]

Our quest for ligands toward the synthesis of functional metal string complexes started from α‐pyridylamido anions. With the modulation of naphthyridylamido anions, the ligands carry less negative charge to be balanced and, thus, to some extent, can tune the oxidation state of the metal centers and the strength of metal–metal interactions. For example, the formation of Ni23+, a mixed‐valence moiety, has been demonstrated. In this paper, high‐bond‐order units of M2 (Mo2 or Ru2) and Ni23+ are introduced and supported by four equatorial ligands of the bisnaphthyridylamido anion (bna−). The resulting compounds are [Ni2Mo2Ni(bna)4Cl2](PF6)3 (1), [Ni2Mo2Ni(bna)4(NCS)2](PF6)3 (2), and [Ni2Ru2Ni(bna)4Cl2](ClO4)3 (3). X‐ray crystallography reveal quadruply bonded characteristics with Mo–Mo distances of 2.133(2) and 2.109(2) Å for 1 and 2, respectively. The Ni2 moieties have a short Ni–Ni distance of 2.331(5) for 1 and 2.334(4) Å for 2, suggesting the formation of mixed‐valence Ni23+ units. It appears that there are no significant metal–metal interactions between Mo2 and its neighboring Ni centers. Characterization using magnetism, voltammetry, electronic absorption, and single‐molecule conductance, however, shows significant influence of Mo2 on the properties of the metal string complexes. [ABSTRACT FROM AUTHOR]

In spite of a large number of antibiotics and chemotherapeutics available for medical use, the emergence of old and new in the last decades revealed a substantial medical need for new classes of . In this paper we report the synthesis, characterization by elemental analysis, Fourier transform infrared and spectroscopies, and antifungal properties of two heteroleptic complexes of albendazole (albz) with Ag(I), using KSCN and o-phenanthroline (phen) as the second ligand, respectively. Both complexes showed a moderate antifungal activity with all the assayed fungi, mainly Candida albicans and Candida tropicalis, that showed no activity against albendazole. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Silver complexes involving vinyltrifluoroborate, (IPr)Ag(CH2=CHBF3) (4), [(IPr)2Ag][CH2=CHBF3] (5), (SIPr)Ag(CH2=CHBF3) (6) and (IPr*)Ag(CH2=CHBF3) (7) have been synthesized by using (NHC)AgNO3 [NHC = IPr (1), SIPr (2) and IPr* (3)] and K(CH2=CHBF3) in a metathesis process. NMR spectroscopic details of 1–7 and X‐ray crystal structures of compounds 5–7 as well as that of a precursor (IPr)AgNO3 are reported. Compounds 6 and 7 are more stable in solution compared to 4 (which forms 5) indicating a supporting ligand effect in the stability of monomeric (NHC)Ag(CH2=CHBF3). Calculated metal–ligand binding energies show that [CH2=CHBF3]− is a significantly better ligand for AgI than CH2=CH2 or isoelectronic CH2=CHCF3. IPr, SIPr and IPr* carbenes coordinate to Ag(CH2=CHBF3) moiety forming silver adducts 4, 6 and 7, with binding energies of about –72.1, –72.1 and –83.8 kcal/mol, respectively. The C=C bond length of [CH2=CHBF3]− (calculated value of 1.341 Å) increases upon coordination to the silver ion. Experimental data show a similar trend for structurally characterized 6 and 7. Electrostatic attraction dominates the bonding between the alkene ligand [C2H3BF3]− and the metal fragments [Ag(IPr)]+ and [Ag(SIPr)]+ in 4 and 6. The strongest orbital interaction involves σ‐donation from the occupied π‐orbital of the [C2H3BF3]− ligand to the vacant orbital of the metal fragment, while AgI→[C2H3BF3]− π‐backbonding is relatively weak but not insignificant. Unsaturated organotrifluoroborate [CH2=CHBF3]– is an excellent ligand for d‐block metal ions as evident from the isolation of two silver(I) complexes, (SIPr)Ag(CH2=CHBF3) and (IPr*)Ag(CH2=CHBF3). [ABSTRACT FROM AUTHOR]

In this work the synthesis, photochemistry, and streptavidin interaction of new [Ru(tpy)(bpy)(SRR′)](PF6)2 complexes where the R′ group contains a free biotin ligand, are described. Two different ligands SRR′ were investigated: An asymmetric ligand 1 where the Ru‐bound thioether is a N‐acetylmethionine moiety linked to the free biotin fragment via a triethylene glycol spacer and a symmetrical ligand 2 containing two identical biotin moieties. The coordination of these two ligands to the precursor [Ru(tpy)(bpy)Cl]Cl was studied in water at 80 °C. In such conditions the coordination of the asymmetric ligand 1 occurred under thermodynamic control. After the reaction, a mononuclear and a binuclear complex were isolated. In the mononuclear complex, the ratio of methionine‐ {[6](PF6)2} vs. biotin‐bound {[7](PF6)2} regioisomer was 5.3 and the free biotin fragment of [6](PF6)2 allowed to purify it from its isomer [7](PF6)2 at small scales using avidin affinity chromatography. Coordination of the symmetrical ligand 2 afforded [Ru(tpy)(bpy)(2)](PF6)2 {[8](PF6)2} in synthetically useful scales (100 mg), good yield (82 %), and without traces of the binuclear impurity. In this complex, one of the biotin remains free whereas the second one is coordinated to ruthenium. Photochemical release of ligand 2 from [8](PF6)2 occurred upon blue light irradiation (465 nm) with a photosubstitution quantum yield of 0.011 that was independent of the binding of streptavidin to the free biotin ligand. A new synthetic strategy is presented for preparing photoactivated chemotherapeutic ruthenium compounds functionalized with a free biotin group. The free biotin fragment, which is bound to ruthenium via a thermally stable Ru–S bond, can still bind to streptavidin. Blue light irradiation resulted in the cleavage of the biotin‐bearing protecting ligand, thus liberating the ruthenium aqua compound. [ABSTRACT FROM AUTHOR]

The synthesis of unsymmetrical β-diketimines with N-aryl-N'-alkyl substitution require at least two condensation steps and tedious purification procedures. An improvement in the preparation of four unsymmetrical N-aryl-N'-alkylpyridyl β-diketimine ligands (HL1-HL4) using 5-Å molecular sieves is reported. The synthesis of four Li complexes (LiL1, LiL2, LiL3, and LiL4) containing N-aryl-N'-alkylpyridyl β-diketimines ligands is also presented. All four Li complexes were fully characterized by 1H NMR spectroscopic, 13C NMR spectroscopic, and elemental analyses. X-ray structure analysis and spectroscopic results indicate that the Li β-diketimine structures and ligand binding modes are governed by the bulkiness of the N-aryl substituent and the length of the pyridyl arm of the N-aryl-N'-alkyl β-diketiminate ligand. [ABSTRACT FROM AUTHOR]

The recently published purely metallo-organic NiI salt [Ni(cod)2][Al(ORF)4] (1, cod=1,5-cyclooctadiene, RF= C(CF3)3) provides a starting point for a new synthesis strategy leading to NiI phosphine complexes, replacing cod ligands by phosphines. Clearly visible colour changes indicate reactions within minutes, while quantum chemical calculations (PBE0-D3(BJ)/def2-TZVPP) approve exergonic reaction enthalpies in all performed ligand exchange reactions. Hence, [Ni(dppp)2][Al(ORF)4] (2, dppp=1,3-bis(diphenylphosphino) propane), [Ni(dppe)2][Al(ORF)4] (3, dppe=1,3-bis(diphenyl- phosphino)ethane), three-coordinate [Ni(PPh3)3] [Al(ORF)4] (4) and a remarkable two-coordinate NiI phosphine complex [Ni(PtBu3)2][Al(ORF)4] (5) were characterised by single crystal X-ray structure analysis. EPR studies were performed, confirming a nickel d9 -configuration in complexes 2, 4 and 5. This result is supported by additional magnetization measurements of 4 and 5. Further investigations by cyclic voltammetry indicate relatively high oxidation potentials for these NiI compounds between 0.7 and 1.7 V versus Fc/Fc+. Screening reactions with O2 and CO gave first insights on the reaction behaviour of the NiI phosphine complexes towards small molecules with formation of mixed phosphine- CO-NiI complexes and oxidation processes yielding new NiI and/or NiII derivatives. Moreover, 4 reacted with CH2Cl2 at RT to give a dimeric NiII ylide complex (4c). As CH2Cl2 is a rather stable alkyl halide with relatively high C@Cl bond energies, 4 appears to be a suitable reagent for more general C@Cl bond activation reactions. [ABSTRACT FROM AUTHOR]

We have developed a short and simple synthesis of tetranuclear palladium(II) complexes that have been structurally confirmed by X-ray analysis. These complexes were formed in about 30 % overall yield by spontaneous metalation of dimethylaminoarene derivatives and exhibit a high stability. We have studied the utility of the tetranuclear palladium(II) complexes as precatalysts for Mizoroki-Heck and Suzuki-Miyaura cross-coupling reactions. Our novel complexes show excellent catalytic activities with high turnover numbers (TON) and high turnover frequencies (TOF) (e.g., for the Suzuki-Miyaura reaction: TON up to 538000 and TOF up to 23400 h−1 at room temperature). [ABSTRACT FROM AUTHOR]

A series of picolyl-functionalised, fluorescent 1,8-naphthalimide ligands (L) have been synthesised and coordinated to ReI to form luminescent cationic complexes of the general form fac-[Re(phen)(CO)3(L)]BF4. The complexes were characterised by using a range of spectroscopic and analytical techniques. One example of a complex was also characterised in the solid-state by using single-crystal X-ray diffraction, revealing a distorted octahedral coordination sphere at ReI and Re-C/Re-N bond lengths within the expected ranges. All ligands were shown to be fluorescent, with the 4-amino derivatives showing intramolecular charge transfer in the visible region (511-534 nm). The complexes generally showed a mixture of ligand-centred and/or 3MLCT emission depending upon the nature of the coordinated 1,8-naphthalimide ligand. For selected complexes, confocal fluorescence microscopy was undertaken by using fission yeast cells ( Schizosaccharomyces pombe) and showed that the structure of the 1,8-naphthalimide ligand influences the uptake and localisation of the rhenium complex. [ABSTRACT FROM AUTHOR]

Mononuclear CuI iodide complexes, [CuI(PPh3)2L] {PPh3 = triphenylphosphine; L = 4-aminoisoquinoline (4-aiq) ( 2), 5-aminoisoquinoline (5-aiq) ( 3), and 5-nitroisoquinoline (niq) ( 4)}, were prepared by three different methods: normally used reactions in the solution state, mechanochemical synthesis, and newly developed solvent-free thermal synthesis. Although no solvent was required for the mechanochemical synthesis of the parent complex [CuI(PPh3)2(iq)] ( 1; iq = isoquinoline), a minimal amount of assisting solvent (PhCN) was required for the mechanochemical syntheses of the three functionalized isoquinoline complexes. The amino-functionalized isoquinoline complexes were successfully synthesized by heating the ground mixture of three types of starting materials at ca. 100 °C, where the PPh3 ligand melted to promote complex formation by acting as the ligand and the solvent. The emission properties strongly depend on the L ligand: Complexes 2 and 3 showed vibronic emission spectra originating from the 3ππ* excited state localized on the L ligand, whereas complex 4 did not show any emission in the visible region. [ABSTRACT FROM AUTHOR]

Two different chromophores, pyrene (Py) and naphthalimide (NI), were introduced as acetylide ligands in a heteroleptic diimine N^N PtII bis(acetylide) complex (Pt-NI-Py) to broaden the absorption bands and enable the intramolecular energy-transfer process. Steady-state and transient spectroscopy were used to study the photophysical properties of the complexes. The lowest triplet state of Pt-NI-Py ( τT = 34 µs) is localized on the pyrene part, although the singlet-state energy level of the naphthalimide unit is lower. Intramolecular energy-transfer processes were observed. Moreover, Pt-NI-Py shows enhanced visible-light harvesting compared with the bis(pyrenylacetylide) complex (Pt-Py) and a lower triplet-state energy level than that of the bis(ethynylnaphthalimide) complex (Pt-NI). The results demonstrate that the relative energy levels of the singlet excited states of the different chromophores do not agree with the relative energy levels of the triplet states of the same chromophores. Efficient triplet-state generation ( ΦΔ = 0.8) gives Pt-NI-Py a high triplet-triplet annihilation (TTA) upconversion efficiency (34 %). [ABSTRACT FROM AUTHOR]

We previously reported the design and synthesis of amphiphilic Ir complex-cationic peptide hybrids ( 2a- 2f), which contain basic peptide sequences such as KKGG (K = lysine, G = glycine) at the 5′-positions ( para position with respect to the C-Ir bond) of three 2-(4′-tolyl)pyridine (tpy) ligands. Among them, 2c- 2e induced the necrosis-like cell death of Jurkat cells through a calcium-dependent pathway, possibly involving a Ca2+-calmodulin (CaM) complex. Herein, we report the synthesis of amphiphilic Ir(ppy)3 complexes (ppy = 2-phenylpyridine) containing the KKGG sequence at the 4′-position of the ppy moiety ( 4a- 4d) to examine the effect of the position of the cationic peptide sequence on the cytotoxicities of the complexes against Jurkat cells. The results of 3-(4,5-dimethly-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT) assays and a mechanistic study indicate that 4b and 4c, which contain C6 and C8 linkers, induce cell death through a calcium-dependent pathway accompanied by membrane disruption in a manner similar to that of 2c- 2e but with smaller half-maximal effective concentration (EC50) values than those of 2c- 2e. The results of the photoaffinity labeling of Jurkat cells with 5b containing a photoreactive 3-trifluoromethyl-3-phenyldiazirine (TFPD) unit and co-staining experiments with specific probes for intracellular organelles suggest that 4b and 4c bind to Ca2+-CaM and are localized in the mitochondria during cell death. [ABSTRACT FROM AUTHOR]

The preparation of the first mononuclear RuII, RuIV, and OsII complexes containing the anion of the bicyclic guanidine 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (Hhpp) as a chelating ligand, namely [RuX{κ²-(N,N')-hpp}(η6-arene)] [arene = p-cymene, X = Cl (2a), Br (2b), I (2c); arene = C6Me6, X = Cl (7)], [RuCl{κ²-(N,N')-hpp}(η³:η³-C10H16)] (9; C10H16 = 2,7-dimethylocta-2,6-diene-1,8-diyl), and [OsCl{κ²-(N,N')-hpp}(η6-pcymene)] (11), is described. Compounds 2a-c, 7, 9, and 11 have been fully characterized by elemental analysis, HRMS, IR and NMR spectroscopy. In addition, the structure of 2a has been unequivocally confirmed by single-crystal X-ray diffraction methods. The catalytic behavior of these metal guanidinate complexes in the base-free redox isomerization of allylic alcohols is explored, with the ruthenium(IV) derivative 9 showing the best performance (TOF up to 5940 h-1). All of the synthesized complexes have also proven to be active in the isomerization of the allylbenzene estragole into the industrially relevant 1-propenylbenzene anethole, with a trans selectivity of up to 95%. [ABSTRACT FROM AUTHOR]

Bis-(6-methylene-2,2′-bipyridine)phenylphosphine ( PN4) was designed as a tailor-made ligand with different metal binding sites (N and P) to support metallophilic interactions between the different coinage metals, as these are far less common than homometallic interactions, typically between gold(I) ions. Furthermore, the phosphorus(V)sulfide derivative of PN4 was synthesized to get additional structural information in the solid state. Two mononuclear gold complexes [( PN4)AuCl] and [( PN4)2Au]ClO4 were synthesized first. Then, the two hetero trimetallic gold complexes [( PN4)2AuAg2](OTf)3 (Tf=triflate) and [( PN4)2AuCu2](OTf)3 were synthesized by selectively filling the bipyridine coordination compartments with the lighter coinage metals. For comparison two trinuclear silver complexes, that is, [( PN4)2Ag3]OTf and [( PN4)(py)2Ag3(μ-Cl)(μ3-Cl)]ClO4 (py=pyridine) were prepared. All compounds were fully characterized including single-crystal X-ray diffraction, 15N,19F and 109Ag NMR spectroscopy. The photophysical properties of the new compounds were determined in the solid state. These revealed a different behavior between the Au-Cu and Au-Ag/Ag-Ag compounds. [( PN4)2AuAg2](OTf)3 was found to be the brightest emitter. Time-dependent density functional calculations were performed to illuminate the differences in the photophysical properties. [ABSTRACT FROM AUTHOR]

Two [Ru(phen)2dppz]2+ derivatives (phen=1,10-phenantroline, dppz=dipyrido[3,2-a:2′,3′-c]phenazine) with different functional groups on the dppz ligand [dppz-7,8-(OMe)2 ( 1), dppz-7,8-(OH)2 ( 2)] have been synthesized, characterized and investigated as photosensitizers (PSs) for photodynamic therapy (PDT) against cancer. Both complexes showed intense red phosphorescence and promising singlet oxygen (1O2) quantum yields of 75 % ( 1) and 54 % ( 2) in acetonitrile. Complex 1 (log Po/w=−0.52, 2.4 nmol Ru per mg protein) was found to be more lipophilic, having also a higher cellular uptake efficiency compared to 2 (log Po/w=−0.20, 0.9 nmol Ru per mg protein). Complex 1 localized evenly in HeLa cells whereas 2, was mainly visualized in the cell membrane by confocal microscopy. In the dark, complex 1 (IC50=36.5 μ m) was found to be more toxic than complex 2 (IC50 >100 μ m) on a HeLa cells monolayer. Importantly, in view of PDT applications, both complexes were found to be non-toxic in the dark towards multicellular HeLa spheroids (IC50>100 μ m). Upon one-photon irradiation (420 nm, 9.27 J cm−2), 1 exhibited higher phototoxicity (IC50=3.1 μ m) than 2 (IC50=16.7 μ m) on HeLa cell monolayers. When two-photon irradiation (800 nm, 9.90 J cm−2) was applied, only 1 (IC50=9.5 μ m) was found to be active toward HeLa spheroids. This study demonstrates that the functional group on the intercalative ligand has a strong influence on the cellular localization and anticancer activity of RuII polypyridyl complexes. [ABSTRACT FROM AUTHOR]

A first-generation machine-assisted approach towards the preparation of hybrid ligand/metal materials has been developed. A comparison of synthetic approaches demonstrates that incorporation of both flow chemistry and microwave heating can be successfully applied to the rapid synthesis of a range of new phenyl-1 H-pyrazoles (ppz) substituted with electron-withdrawing groups (−F, −CF3, −OCF3, and −SF5). These, in turn, can be translated into heteroleptic complexes, [Ir(ppz)2(bipy)]BF4 (bipy=2,2′-bipyridine). Microwave-assisted synthesis for the IrIII complexes allows isolation of spectroscopically pure species in less than 1 h of reaction time starting from IrCl3. All of the new complexes have been characterised photophysically (including nanosecond time-resolved transient absorption spectroscopy), electrochemically, and by TD-DFT studies. The complexes exhibit ligand-dependent, tuneable, green-yellow luminescence (500-560 nm), with quantum yields in the range 5-15 %. [ABSTRACT FROM AUTHOR]

Mononuclear and trinuclear bis-cyclometallated IrIII complexes of the host ligands tris(4-[4′-methyl-2,2′-bipyridyl]methyl)cyclotriguaiacylene ( L1) and tris(4-(4′-methyl-2,2′- bipyridyl)carboxy)cyclotriguaiacylene ( L2) have been prepared. Complexes [{Ir(ppy)2}3( L1)](PF6)3 ( 1.1), [{Ir(ppy)2}( L1)](PF6)3 ( 1.2), [{Ir(ppy)2}3( L2)](PF6)3 ( 2.1) and [{Ir(ppy)2}( L2)](PF6)3 ( 2.2) (where ppy=phenylpyridinato) showed distinct photophysical properties depending on the L ligand. Complexes featuring the L1 ligand were comparatively blue-shifted in solution, with longer lifetimes and higher quantum yields. The mixed bis-cyclometallated IrIII complexes [{Ir(ppy)2}{Ir(dFppy)2}2( L1)](PF6)3 ( 1.3), [{Ir(ppy)2}{Ir(dFppy)2}2( L2)](PF6)3 ( 2.3), [{Ir(ppy)2}2{Ir(dFppy)2}( L1)](PF6)3 ( 1.4) and [{Ir(ppy)2}2{Ir(dFppy)2}( L2)](PF6)3 ( 2.4) (where dFppy=2,4-difluorophenylpyrinato) were also synthesised. Steady-state and time-resolved spectroscopy, along with electrochemical investigations, show that the Ir(III) chromophores within these mixed Ir-environment species behave as isolated centres, with no energy transfer or electronic communication between them. [ABSTRACT FROM AUTHOR]

Catellani reactions of aryl iodides allow the double functionalization at the ortho and ipso positions in one pot. Catellani reactions involving a nitrene intermediate are not yet known. In this paper, a few palladium amino complexes were prepared from PdCl2, anthranil and iodoarenes, and their structures were determined by X‐ray single‐crystal diffraction. These complexes are supported by a pincer C,N,O tridentate ligand forming fused six‐membered palladacycles. The high stability of the palladium complexes inhibits their reductive elimination. Novel palladium amido complexes were synthesized from palladium chloride, phosphines, anthranil, and norbornene via one‐pot reaction, and their structures were characterized. [ABSTRACT FROM AUTHOR]

In this paper, three new copper (II) complexes, [Cu(4‐mphen)(tyr)(H2O)]ClO4(1), [Cu(5‐mphen)(tyr)(H2O)]ClO4·1.5H2O (2) and [Cu (tmphen)(tyr)(NO3)]0.5H2O (3) (4‐mphen: 4‐methyl‐1,10‐phenanthroline, 5‐mphen: 5‐methyl‐1,10‐phenanthroline, tmphen: 3,4,7,8‐tetramethyl‐1,10‐phenanthroline and tyr: L‐tyrosine), were synthesized and characterized using elemental analyses, FT‐IR, ESI‐MS, cyclic voltammetry and single‐crystal X‐ray diffraction. It was found that the complexes adopt a distorted five‐coordinate square pyramidal geometry. The interaction of the three complexes with calf thymus DNA was also investigated using UV–visible absorption spectra, ethidium bromide and Hoechst 33258 displacement assay and thermal denaturation. The DNA cleavage activity of the complexes, monitored using gel electrophoresis, showed significant damage of the pUC19 plasmid DNA. Binding activity of bovine serum albumin (BSA) reveals that these complexes can strongly quench the fluorescence of BSA through a static quenching mechanism. The results suggested that interaction of the complexes with DNA occurred through a partial intercalation into the minor grooves of DNA. In addition, interaction of the complexes with bovine serum albumin quenched the fluorescence emission of the tryptophan residues of the protein binding constants and thermodynamic parameters were obtained from the fluorescence quenching experiments at different temperatures. Free radical scavenging activities of the complexes were determined by various in vitro assays such as 1,1‐diphenyl‐2‐picryl‐hydrazyl free radicals (DPPH˙) and H2O2 scavenging methods. In addition, the cytotoxicity of these complexes in vitro on tumor cell lines (Caco‐2 and MCF‐7) was examined by XTT and showed better antitumor effect on the tested cells. ROS (reactive oxygen species) and comet experiments are consistent with each other and these complexes lead to DNA damage via the production of ROS. The effect of the hydrophobic properties of the synthesized complexes on DNA and BSA binding activities were discussed. A new ternary copper (II) tyrosinate complexes containing methyl substituted 1,10‐phenanthrolines have been synthesized and characterized by CHN analysis, cyclic voltammetry, ESI‐MS, FTIR and single‐crystal X‐ray diffraction techniques. They have been tested for their in vitro DNA/BSA interactions by the spectroscopic methods. These complexes exhibited higher cytotoxic and ROS activities. [ABSTRACT FROM AUTHOR]

The viability of making [Fe(CB6)L] (L = H2, N2, O2, nitric oxide [NO−, NO, and NO+], CO2, and hydrocarbons [CH4, C2H6, C2H4, and C6H6]) has been investigated by density functional theory (DFT) calculations. The complexes 2- 18 are thermodynamically stable and may be synthesized. The small molecules are activated to some extent after complexation. Molecular orbital and Δ G calculation revealed that the molecular hydrogen and hydrocarbons can be chemically adsorbed and desorbed on [Fe(CB6)] without any significant chemical modification and therefore [Fe(CB6)] may serve as a storage material. The N2, O2, and nitric oxide (NO−, NO, and NO+) can be activated using [Fe(CB6)]. Proton, carbon, boron, and nitrogen NMR chemical shift calculation predicts drastic chemical shift difference before and after the complexation of [Fe(CB6)] with small molecules. This new findings suggest that the CB62− ligand-based complex may provide several applications in the future. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Derivatisation of Grignard synthons "PhAeI(thf)n" (Ae = Mg‐Ba) prepared in situ from reactions of metal filings and iodobenzene provides a one‐pot synthesis of heteroleptic N donor alkaline earth iodide complexes. Protolysis of "PhAeI(thf)n" with 3,5‐diphenylpyrazole (Ph2pzH) yields pyrazolate complexes [Mg2(µ‐Ph2pz)2(I)2(thf)3] (1), [Ae(Ph2pz)(I)(thf)4] (Ae = Ca (2), Sr (3)), and [Ba2(Ph2pz)2(µ‐I)2(thf)8] (4). Addition of the Ae‐Ph moiety to carbodiimide MesN=C=NMes (Mes = 2,4,6‐(CH3)3C6H2) gave a series of benzamidinate iodide complexes [Ca2{(MesN)2CPh}2(µ‐I)2(thf)4] (6), [Sr{(MesN)2CPh}(I)(thf)4] (7), and [{Ba{(MesN)2CPh}(µ‐I)(thf)3}∞] (8). By contrast a symmetrical magnesium complex [Mg{(MesN)2CPh}2(thf)] (5) was obtained by Schlenk redistribution. These syntheses proceed without pre‐activation of the metal for strontium and barium, and after activation with 2 mol‐% iodine for calcium. The heavy alkaline earth metal complexes are the first examples of heteroleptic halide pyrazolate or amidinate complexes for strontium and barium. Complexes 1, 3, 4 and 6–8 were characterised crystallographically, revealing diverse structural chemistry of heteroleptic amidinate and pyrazolate iodide complexes across the alkaline earth series. A highlight is [Ba{(MesN)2CPh}(µ‐I)(thf)3]∞ (8) – an iodide bridged infinite 1‐D polymer. Heavy Grignard reagents "PhAeI(thf)n" can be protolysed by pyrazoles to yield pyrazolate iodide complexes or add to carbodiimides to give benzamidinate iodide complexes. PhAeI(thf)n' is straightforward to prepare and its derivatisation enables direct access to bifunctional alkaline earth complexes from the metal. X‐ray characterisation has enabled structural comparisons across the Ae series (Mg‐Ba) for new heteroleptic iodide complexes. [ABSTRACT FROM AUTHOR]

Ligands such as N‐2‐pyrimidylimidoyl‐2‐pyrimidylamidine (Pm2ImAm) possess both a bidentate and tridentate coordination site within a single ligand framework. Taking advantage of this, two tetranuclear complexes with manganese ([MnIIIMnII3(Pm2ImAm)3Cl6]) and iron ([FeIII4(Pm2ImAm)3Cl9]) have been isolated, characterized by single‐crystal X‐ray analysis, and their magnetic properties have been investigated through SQUID magnetometry and Mössbauer spectroscopy. As well, a mononuclear ([FeIII(Pm2ImAm)Cl3]) and binuclear ([MnII2(µ‐Cl)2(Pm2ImAm)2Cl2]) complex employing this ligand framework were also isolated, characterized by single‐crystal X‐ray analysis and their magnetic properties were investigated. For comparison purposes, the previously reported mononuclear complexes [MnIII(Py2ImAm)3] and [FeIII(Py2ImAm)3] were also probed here via SQUID magnetometry due to the similarities between these mononuclear systems and fragments of the tetranuclear complexes. Through this approach, clear interpretation of the magnetic properties in [MnIIIMnII3(Pm2ImAm)3Cl6] and [FeIII4(Pm2ImAm)3Cl9] was achieved. These results reveal that employing our N‐imidoylamidine ligands facilitates the rational design of polynuclear complexes with differing metal ion spin states. Rational design of tetranuclear complexes with manganese and iron was achieved by employing N‐imidoylamidine ligands. Evaluation via SQUID magnetometry and Mössbauer spectroscopy reveal a unique combination of low and high spin states for the metal centers within these cluster aggregates. [ABSTRACT FROM AUTHOR]

During an investigation into the potential union of Lewis basic isothiourea organocatalysis and gold catalysis, the formation of gold‐isothiourea complexes was observed. These novel gold complexes were formed in high yield and were found to be air‐ and moisture stable. A series of neutral and cationic chiral gold(I) and gold(III) complexes bearing enantiopure isothiourea ligands was therefore synthesized and fully characterized. The steric and electronic properties of the isothiourea ligands was assessed through calculation of their percent buried volume and the synthesis and analysis of novel iridium(I)‐isothiourea carbonyl complexes. The novel gold(I)‐ and gold(III)‐isothiourea complexes have been applied in preliminary catalytic and biological studies, and display promising preliminary levels of catalytic activity and potency towards cancerous cell lines and clinically relevant enzymes. A golden touch: An investigation into the union of isothiourea organocatalysis and gold catalysis led to the discovery of bench‐stable gold‐isothiourea complexes. A series of neutral and cationic chiral gold(I) and gold(III) complexes bearing enantiopure isothiourea ligands have been synthesized, with the steric and electronic properties of the isothiourea ligands also assessed. The novel complexes have also been applied in preliminary catalytic and biological studies. [ABSTRACT FROM AUTHOR]

The photophysical properties of the compound [(ThiaSO2)(MnII)2(DMF)4(H2O)2] (2), ThiaSO2 = p‐tert‐butylsulfonylcalix[4]arene, are presented and compared to the ones of [(ThiaSO2)2(MnII)4F]K (1). The orange luminescence of 2 is attributed, as for 1, to the MnII centred 4T1→6A1 transition and shows, for this type of complex, the weak influence of the Mn2+ coordination and ThiaSO2 conformation on this luminescence, the temperature and pressure dependence and quenching by molecular dioxygen of which are reported for 2. The latter is attributed to energy transfer from the 4T1 state exciting dioxygen to its 1Σ+g state and is responsible for the photosynthesis of the [(ThiaSO2)(MnIII)(DMF)2]Na (3) complex in DMF solution from 1 or 2. This reaction was studied by UV/Visible and EPR spectroscopy. The molecular structure and EPR spectroscopy of 3 are also presented. The photo‐physical properties of the compound [(ThiaSO2)(MnII)2(DMF)4(H2O)2] (2), ThiaSO2 = p‐tert‐butylsulfonylcalix[4]arene, are presented and compared to the ones of [(ThiaSO2)2(MnII)4F]K. Both compounds show intense Mn2+ centred luminescence and photo‐oxidation in N,N‐diméthylformamide solution to form [(ThiaSO2)(MnIII)(DMF)2]K (3). [ABSTRACT FROM AUTHOR]

A mononuclear, 14‐electron iron(II) bis(guanidinate) complex, [Fe(HGua)2] [HGua– = (2,6‐Me2C6H3N)C(NHiPr)(NiPr)–] (3), was easily prepared by treatment of anhydrous FeCl2 with 2 equiv. of [Li(HGua)(tmeda)] (2, tmeda = Me2NCH2CH2NMe2). Complex 3 reacts readily with AgCl, Br2, and I2, respectively, leading to the formation of the corresponding iron(III) bis(guanidinate) halide complexes [Fe(HGua)2X] {X = Cl (4), Br (5), I (6)}. Addition of 3 to elemental selenium gives a di‐iron(III) µ‐selenido complex [{Fe(HGua)2}2(µ‐Se)] (9). Complex 3 also reacts readily with PhEEPh (E = S, Se), affording the respective iron(III) bis(guanidinate) chalcogenolate complexes [Fe(HGua)2(EPh)] {E = S (7), Se (8)}. A subsequent reaction of the iron(III) phenylselenolate complex [Fe(HGua)2(SePh)] (8) with I2 yields a mixture of [Fe(HGua)2I] (6) and an interesting selenium compound [(HGua)2SeI2] (10). A mononuclear, 14‐electron iron(II) bis(guanidinate) complex, [Fe(HGua)2] [HGua– = (2,6‐Me2C6H3N)C(NHiPr)(NiPr)–] was prepared and characterized. Complex [Fe(HGua)2] readily reduced AgCl, Br2, I2, PhEEPh (E = S, Se) and elemental Se to yield the corresponding bis(guanidinate) iron(III) halide, phenylchalcogenolate, and selenide complexes. [ABSTRACT FROM AUTHOR]

The Front Cover shows a streptavidin molecule functionalized with a light‐sensitive Ru–polypyridyl complex via a bis‐biotin ligand. One biotin is free and strongly interacts with the protein pocket, while the other is coordinated to ruthenium to hold the complex onto the protein in the dark. Upon blue light irradiation, the bond between the coordinated biotin and Ru is broken, which releases the Ru complex in solution. The synthesis and light cleavage strategy proposed in the article is a new step towards the use of streptavidin for cancer cell targeting of Ru‐based photoactivated chemotherapy. More information can be found in the Full Paper by S. Bonnet et al. For more on the story behind the cover research, see the Cover Profile. [ABSTRACT FROM AUTHOR]

A new redox‐active, diarylamido‐based ligand (LN3P2) capable of κ5‐N,N,N,P,P chelation has been used to prepare a series of complexes with the general formula [MII(LN3P2)]X, where M = Fe (1; X = OTf), Co (2; X = ClO4), or Ni (3; X = ClO4). The diarylamido core of monoanionic LN3P2 is derived from bis(2‐amino‐4‐methylphenyl)amine, which undergoes condensation with two equivalents of 2‐(diphenylphosphanyl)benzaldehyde to provide chelating arms with both arylphosphine and imine donors. X‐ray structural, magnetic, and spectroscopic studies indicate that the N3P2 coordination environment generally promotes low‐spin configurations. Three quasi‐reversible redox couples between +1.0 and –1.5 V (vs. Fc+/Fc) were observed in voltammetric studies of each complex, corresponding to MII/MIII oxidation, LN3P2‐based oxidation, and MII/MI reduction (in order of highest to lowest potential). Spectroscopic and computational analyses of 3ox – generated via chemical one‐electron oxidation of 3 – revealed that a stable diarylaminyl radical (LN3P2·) is formed upon oxidation. The ability of the CoII complex (2) to function as an electrocatalyst for H2 generation was evaluated in the presence of weak acids. Moderate activity was observed using 4‐tert‐butylphenol as the proton source at potentials below –2.0 V. The insights gained here will assist in the future design of pentadentate mixed N/P‐based chelates for catalytic processes. A new pentadentate, diarylamido‐based ligand is used to prepare a series of 3d metal complexes (Fe, Co, Ni) with N3P2 coordination. The complexes exhibit multiple metal‐ and ligand‐based redox events that were investigated with voltammetry. The cobalt complex behaves as an electrocatalyst for H2 generation in the presence of weak acids. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane (DAPTA) with metal salts of CuII or NaI/NiII under mild conditions led to the oxidized phosphane derivative 3,7‐diacetyl‐1,3,7‐triaza‐5‐phosphabicyclo[3.3.1]nonane‐5‐oxide (DAPTA=O) and to the first examples of metal complexes based on the DAPTA=O ligand, that is, [CuII(μ‐CH3COO)2(κO‐DAPTA=O)]2 (1) and [Na(1κOO′;2κO‐DAPTA=O)(MeOH)]2(BPh4)2 (2). The catalytic activity of 1 was tested in the Henry reaction and for the aerobic 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO)‐mediated oxidation of benzyl alcohol. Compound 1 was also evaluated as a model system for the catechol oxidase enzyme by using 3,5‐di‐tert‐butylcatechol as the substrate. The kinetic data fitted the Michaelis–Menten equation and enabled the obtainment of a rate constant for the catalytic reaction; this rate constant is among the highest obtained for this substrate with the use of dinuclear CuII complexes. DFT calculations discarded a bridging mode binding type of the substrate and suggested a mixed‐valence CuII/CuI complex intermediate, in which the spin electron density is mostly concentrated at one of the Cu atoms and at the organic ligand. [ABSTRACT FROM AUTHOR]

Five new heteroleptic zirconium and hafnium complexes were synthesized. The complexes carry chloro ligands as well as differently substituted phenoxy benzoxazole ligands [HL1 = 2‐(2′‐hydroxyphenyl)benzoxazole, HL2 = 2‐(2′‐hydroxynaphthyl)benzoxa‐zole, HL3 = 2‐(2′‐hydroxy‐3′,5′‐di‐tert‐butylphenyl)benzoxazole]. They were characterized by 1H and 13C{1H} NMR spectroscopy as well as by elemental analyses and X‐ray diffraction experiments. The molecular structures in the crystals show distorted octahedral or capped trigonal prismatic coordination spheres. The intermolecular interactions influencing the packing patterns are mainly H···Cl contacts. For the hafnium complex [Cl2Hf(L3)2] a dynamic behavior in solution was examined using temperature dependent 1H NMR spectroscopy. The photo‐physical data show that in all cases fluorescence arises from a short‐lived excited state, the emission maxima being located in the blue spectral region. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of a dimeric base‐stabilized cobaltosilylene complex and its catalytic reactions are described. Treatment of the amidinato silicon(I) dimer [LSi:]2 (1; L=PhC(NtBu)2) with CoBr2 in toluene for 10 days afforded the dimeric amidinato cobaltosilylene [(LSi)μ‐{CoBr(LSiBr)}]2 (2), which is speculated to proceed via “LSiCoBr” and “LSiBr” intermediates in the reaction. Compound 2 is paramagnetic, with an effective magnetic moment of 2.8 μB. Its electronic structure was elucidated by single‐crystal X‐ray crystallography and DFT studies. It was capable of catalyzing C−H bond functionalization, in which a combination of 2, phosphine and MeMgI can regio‐ and stereoselectively promoted the addition of the C≡C triple bonds in alkynes to the ortho‐C−H position in arylpyridines. In addition, compound 2 catalyzed Kumada‐type coupling reactions between aryl chlorides and the Grignard reagent 2‐mesitylmagnesium bromide. [ABSTRACT FROM AUTHOR]

Deprotonation of 3,6‐di‐tert‐butyl‐1,8‐bis((diisopropyl‐phosphanyl)‐methyl)‐9H‐carbazole [(CbzdiphosiPr)H] (1) with LiHMDS and reaction with (cod)PtCl2 yielded the corresponding platinum chloride complex (CbzdiphosiPr)PtCl (2), which was converted quantitatively into the bromide 3 and iodide 4 analogues by treatment with TMS‐Hal (Hal = Br, I). Moreover, it was possible to prepare a PtIV species by oxidative addition of CsBr3 to compound 3. Furthermore, the hydride complexes of all group 10 metals were obtained by treatment of compound 1 with the M(0) precursors Ni(cod)2, Pd(PtBu3)2, and Pt(PtBu3)2. [ABSTRACT FROM AUTHOR]

Abstract: Transition‐metal carbene complexes and their reactivities are a key topic of chemistry. They are an integral part of researches in catalysis, organic synthesis, coordination chemistry, and numerous other areas. In this context, we report the synthesis of a low‐valent bis(η5:η1‐(di‐p‐tolyl)‐pentafulvene)niobium chloride. Owing to the π‐η5:σ‐η1 coordination mode of the pentafulvenes and the resulting high nucleophilic character of the exocyclic carbon atom of the ligand, the bis(η5:η1‐pentafulvene)niobium complex is able to achieve the umpolung of a coordinated vinyl unit and the resulting formation of the first η5:η1 cyclic niobium Schrock carbene complex. This new synthetic route is, in comparison to classical α‐hydrogen elimination reactions or thermolysis of diazo compounds, completely unprecedented. The reactivity of the cyclic carbene function and the remaining fulvene ligand is demonstrated by double N−H bond activation of primary amines to niobium imido complexes. [ABSTRACT FROM AUTHOR]

In order to enhance the thermal stability of the barium salt of 5,5′‐bistetrazole (H2BT), carbohydrazide (CHZ) was used to build [Ba(CHZ)(BT)(H2O)2]n as a new energetic coordination compound by using a simple aqueous solution method. It was characterized by FT‐IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. The crystal belongs to the monoclinic P21/c space group [a = 8.6827(18) Å, b = 17.945(4) Å, c = 7.2525 Å, β = 94.395(2)°, V = 1126.7(4) Å3, and ρ = 2.356 g·cm–3]. The BaII cation is ten‐coordinated with one BT2–, two shared carbohydrazides, and four shared water molecules. The thermal stabilities were investigated by differential scanning calorimetry (DSC) and thermal gravity analysis (TGA). The dehyration temperature (Tdehydro) is at 187 °C, whereas the decomposition temperature (Td) is 432 °C. Non‐isothermal reaction kinetics parameters were calculated by Kissinger's method and Ozawa's method to work out EK = 155.2 kJ·mol–1, lgAK = 9.25, and EO = 158.8 kJ·mol–1. The values of thermodynamic parameters, the peak temperature (while β → 0) (Tp0 = 674.85 K), the critical temperature of thermal explosion (Tb = 700.5 K), the free energy of activation (ΔG≠ = 194.6 kJ·mol–1), the entropy of activation (ΔS≠ = –66.7 J·mol–1), and the enthalpy of activation (ΔH≠ = 149.6 kJ·mol–1) were obtained. Additionally, the enthalpy of formation was calculated with density functional theory (DFT), obtaining ΔfH°298 ≈ 1962.6 kJ·mol–1. Finally, the sensitivities toward impact and friction were assessed according to relevant methods. The result indicates the compound as an insensitive energetic material. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of [C^C)Au(OEt2)2]+ with 1,5‐cyclooctadiene or norbornadiene affords the corresponding olefin complexes [(C^C)Au(COD)]SbF6 and [(C^C)Au(NBD)]SbF6, which are thermally stable in solution and the solid state (C^C=4,4′‐di‐tert‐butylbiphenyl‐2,2′‐diyl). The crystal structures of these complexes have been determined. By contrast, dienones such as dibenzylideneacetone are O‐ rather than C=C‐bonded. The reactions of (C^C)Au(OAcF)(L) (L=PMe3 or CNxyl) with B(C6F5)3 in the presence of bis(1‐adamantyl)acetylene give the mixed‐ligand alkyne complexes [(C^C)Au(AdC≡CAd)(L)]+, the first complexes of their type in gold chemistry. In the presence of an excess of acetylene these compounds are thermally stable in solution and as solids. The bonding of n‐ and π‐donor ligands to AuIII fragments and the effect of the trans influence exerted by N‐ and C‐donors was explored with the aid of DFT calculations. Results show that the Au−L bond enthalpies trans to anionic C are 35–60 % of the enthalpies trans to N, with strong π‐acceptors being particularly affected. In comparison with [Me2Au]+, the [(C^C)Au]+ fragment is more polar and in bond enthalpy terms resembles Me2Pt. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of two new RuII complexes, a mononuclear complex [RuII(MeMPTP)(bpp)Cl]PF6 (1) and a dinuclear complex [RuII(MeMPTP)(bpp)RuII(bpy)2Cl](PF6)3 (2), [where MeMPTP = 4′‐(4‐methylmercaptophenyl)‐2,2′:6′2′′‐terpyridine, bpp = 2,3‐bis(2‐pyridyl)pyrazine, bpy = 2,2′‐bipyridine] is reported. Single‐crystal X‐ray structural determination of the compounds unambiguously confirms the formation of the complexes 1 and 2. Catalytic investigations of the complexes for the chemical oxidation of water in the presence of Ce4+ as a sacrificial oxidant reveals a higher rate of O2 evolution by the dinuclear complex 2 over the physical mixture of complex 1 and a redox mediator, [Ru(bpy)3]2+ (med), followed by the mononuclear complex 1. The enhancement in the catalytic rate of O2 evolution by 2 is ascribed to being due to the intramolecular redox process, which facilitates the facile formation of a high‐valent ruthenium–oxo species that is required for water oxidation through a cooperative effect. The present study highlights the importance of the intramolecular redox process over the intermolecular redox process. [ABSTRACT FROM AUTHOR]

We present the first example of non‐classical hydrogen bonding in CuI complexes. To this end, we have studied the coordination capacity of the tripodal phosphine ligands HTIM(PR2)3 {tris[1‐(di‐R‐phosphanyl)‐3‐methyl‐1H‐indol‐2‐yl]methane, R = Ph, iPr} towards copper, leading to a series of eight CuI complexes [{HTIM(PR2)3}CuX] [R = Ph (1–4), iPr (5–8); X = Cl–, I–, OTf–, BF4–]. An anagostic interaction in the CuI complexes has been proposed based on the results of 1H NMR, ultrahigh‐resolution X‐ray diffraction, and theoretical [atoms‐in‐molecules (AIM) and natural bonding orbital (NBO)] analyses of the electron density. Among the different synthesized complexes, [{HTIM(PPh2)3}CuOTf] (2) shows the strongest Cu···H–C interaction with a linear geometry (179.98°) and the shortest distance described so far [d(Cu–H) = 1.9 Å] in its toluene solvated form. Both parameters are characteristic of 3c–4e– interactions. In addition, we have found that these tripodal ligands exhibit unprecedented selectivity towards CuI ions. The synthesized HTIM(PR2)3CuI complexes have been found to be catalytically active and selective for the hydroboration of CO2 to formic acid. [ABSTRACT FROM AUTHOR]

Abstract: Metallacycles with chelating polydentate conjugated‐carbon chain ligands are called carbolong complexes, which are expected to have interesting properties. In this work, the preparation of 12‐carbon carbolong complexes in which all of the coordinated atoms in the equatorial plane are carbon atoms was studied. With the help of the well‐established mechanism, a new approach to prepare coplanar carbolong complexes bearing different organic functional groups was developed by adding different terminal alkynes in sequence. In the presence of HBF4, these coplanar carbolong complexes were converted to η3‐allyl osmapentalene derivatives, which can be produced directly from the reaction of cyclopropaosmapentalene 1 with terminal alkynes in the presence of AgBF4 under anhydrous conditions. This study offers a new route for the preparation of functional osmium carbolong complexes with excellent photothermal properties, which can be used to prepare photothermal materials. [ABSTRACT FROM AUTHOR]

Four cobalt(II) complexes [Co(L1)Cl]PF6/ClO4 (C1‐PF6/C1‐ClO4), [Co(L2)Cl]PF6 (C2‐PF6), [Co(L3)Cl]PF6/ClO4·H2O·CH3OH (C3‐PF6/C3‐ClO4·H2O·CH3OH) and [Co(L4)Cl]PF6·2H2O (C4‐PF6·2H2O), in which L1–L4 refer to [(3,5‐dimethyl‐4‐methoxy‐2‐pyridylmethyl)bis(2‐pyridylmethyl)]amine, [(3,4‐dimethoxy‐2‐pyridylmethyl)‐(2‐pyridylmethyl)]amine, [bis(3,5‐dimethyl‐4‐methoxy‐2‐pyridylmethyl)‐(2‐pyridylmethyl)]amine and {[bis(3,4‐dimethoxy‐2‐pyridyl)methyl]‐(2‐pyridylmethyl)}amine, respectively, were synthesized and structurally characterized. Single‐crystal X‐ray crystallography confirmed the trigonal bipyramidal geometries of the complexes. In aqueous acetonitrile solution, the green complexes dissolve with the formation of a yellow solution with biphasic kinetic behavior. In 60 % H2O/CH3CN (by volume) and 25 °C, the first step corresponds to the rapid formation of [Co(L)(CH3CN)]2+ (ka = 0.16–2.0 min–1) followed by a slow conversion into [Co(L)(H2O)]2+ (kb = 6.3 × 10–3–0.10 min–1), where the two species exist in equilibrium. The spectrophotometric and conductometric titrations of the complexes were consistent with the proposed equilibrium. The coordinated H2O in the aqua complexes, [Co(L)(H2O)]2+ have pKa values ranging from 8.3 to 8.5 at 25 °C. All complexes cleaved plasmid DNA at micromolar concentrations within 2 h at 37 °C and pH 7.0 under hydrolytic conditions. Compared to the uncatalyzed cleavage of DNA, rate enhancements of up to 100 million were achieved in case of complex C4‐PF6. [ABSTRACT FROM AUTHOR]

A series of chromone Schiff base complexes were prepared and analytically as well as spectroscopically characterized. The ligand was found to act as a monobasic tridentate ligand bonded covalently or coordinatively to the metal ion via deprotonated hydroxyl group, azomethine nitrogen atom and carbonyl oxygen atom of antipyrine moiety. Both electronic spectra and magnetic measurements indicated an octahedral or a distorted octahedral geometry around the metal ions for all metal complexes except the nickel complex, which had a tetrahedral geometry. In addition, the ability of the newly prepared compounds to activate the tumour suppressor p53 in cancer cells was studied, with zinc and copper complexes showing promising activities for p53 ubiquitination compared with diphenylimidazole (reference drug). [ABSTRACT FROM AUTHOR]

Abstract: The first SiIV corrole complexes were synthesized in good yields by treatment of meso‐triarylcorroles with tetrachlorosilane in 1,2‐dichloroethane at 60 °C. The central silicon atom possesses a square‐pyramidal coordination geometry with slightly longer Si−N bond lengths as compared with those of known triazacorrole SiIV complexes. The SiIV corrole complexes exhibit sharp and blue‐shifted absorption spectra and larger fluorescence quantum yields as compared with the corresponding free‐base corroles. A μ‐oxo dimer of a SiIV corrole was synthesized upon treatment with methanesulfonyl chloride in pyridine at 100 °C. This dimer shows a face‐to‐face structure with a 90° twist in the solid state. Although the dimer exhibits a blue‐shifted Soret band, reflecting the face‐to‐face geometry, it displays a largely red‐shifted and broad fluorescence spectrum with a large Stokes shift, suggesting a large structural change in the S1 state. These intriguing optical properties have been comprehensively studied by magnetic circular dichroism (MCD) spectroscopy, femtosecond transient absorption (fs‐TA) measurements, and theoretical calculations. [ABSTRACT FROM AUTHOR]

Abstract: We report the gas‐phase synthesis of stable 20‐electron carbonyl anion complexes of group 3 transition metals, TM(CO)8− (TM=Sc, Y, La), which are studied by mass‐selected infrared (IR) photodissociation spectroscopy. The experimentally observed species, which are the first octacarbonyl anionic complexes of a TM, are identified by comparison of the measured and calculated IR spectra. Quantum chemical calculations show that the molecules have a cubic (Oh) equilibrium geometry and a singlet (1A1g) electronic ground state. The 20‐electron systems TM(CO)8− are energetically stable toward loss of one CO ligand, yielding the 18‐electron complexes TM(CO)7− in the 1A1 electronic ground state; these exhibit a capped octahedral structure with C3v symmetry. Analysis of the electronic structure of TM(CO)8− reveals that there is one occupied valence molecular orbital with a2u symmetry, which is formed only by ligand orbitals without a contribution from the metal atomic orbitals. The adducts of TM(CO)8− fulfill the 18‐electron rule when only those valence electrons that occupy metal–ligand bonding orbitals are considered. [ABSTRACT FROM AUTHOR]

Abstract: Silicon complexation of a [38]octaphyrin (1) was accomplished by reaction with an excess amount of MeSiCl3 in the presence of N,N‐diisopropylethylamine, thus giving an aromatic [38]octaphyrin bis(silicon) complex 2. This complex was interconvertible with an antiaromatic [36]octaphyrin congener (3) by oxidation with MnO2 and reduction with NaBH4. Curiously, mild oxidation of 2 with ferrocenium hexafluorophosphate afforded a [37]octaphyrin bis(silicon) complex 4 as an stable radical cation that can be stored under ambient conditions in the solid state. Owing to the two NNNCC‐five‐coordinated Si atoms bearing trigonal bipyramidal geometry, these octaphyrin bis(silicon) complexes take on similar and rigid figure‐of‐eight structures with different consecutive numbers of conjugated π‐electrons (38, 37, and 36), and are all stable. [ABSTRACT FROM AUTHOR]

[14]Oxatriphyrins(2.1.1) incorporating a furan moiety in the macrocycle have been synthesized by intramolecular McMurry coupling of oxatripyrromethane followed by oxidation. The [14]oxatriphyrins(2.1.1) are highly planar structures with 14π‐electron aromaticity, inducing typical porphyrin‐like absorption and fluorescence features. Compared with [14]thiatriphyrin(2.1.1) and arene‐fused oxatriphyrins(2.1.1), arene‐unperturbed [14]oxatriphyrins(2.1.1) exhibit stronger aromatic characteristics and fluorescence properties. The borylation of [14]oxatriphyrins(2.1.1) with dichloro(phenyl)borane resulted in the formation of boron complexes with a reduced olefin bridge. As a result of the reduction, the macrocycles of these boron complexes lost their aromatic properties, although the targeted boron complexes were predicted to have distinct anti‐aromatic properties by DFT calculations. The resultant ethane‐bridged oxatripyrrins exhibit intense emission because of their rigid structures. [ABSTRACT FROM AUTHOR]

An efficient method for the iron(III) porphyrin catalyzed olefination of various aldehydes with 2,2,2‐trifluorodiazoethane under neutral conditions is described. This transformation was shown to have a broad substrate scope and provide the corresponding CF3‐substituted alkenes in good yields. The number of equivalents of PPh3 that is used in this reaction is crucial to the success of the olefination process. This reaction is a useful supplement to the synthetic applications of CF3CHN2. [ABSTRACT FROM AUTHOR]

Eight new O‐alkyldithiophosphato nickel complexes 1–8 with chelating aminodiphosphine ligands have been successfully synthesized in moderate yields by the treatment of O,O′‐alkydithiophosphoric acid salts (R1O)2P{S}SH·Et2NH (R1 = CH3, CH2CH3) with nickel aminodiphosphine precursors Ni[(Ph2P)2NR2]Cl2 [R2 = (CH2)3OCH3, (CH2)3SCH3, (CH2)2CH(CH3)2, CH(CH3)C6H5] in the presence of Et3N at room temperature. Meanwhile, reactions of Ni(S2P{OR1}2)2 and aminodiphosphine ligands (Ph2P)2NR2 in CHCl3 solvents at room temperature also resulted in the formation of the target complexes 1–8 in satisfactory yields. The two synthetic routes are found to be efficient pathways to prepare O‐alkyldithiophosphato nickel complexes with chelating aminodiphosphine ligands. All the new complexes were fully characterized by elemental analysis, FTIR and NMR (1H, 13C, 31P) spectroscopy, and particularly for three of them by X‐ray crystallography. Moreover, these complexes were found to be catalysts for hydrogen production in the presence of a weak acid under electrochemical conditions. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of five new and closely related homoleptic iron(II) β‐ketoiminate complexes is reported. Molecular structures of compounds 1, 2, and 5 were determined by single‐crystal XRD, which revealed monomeric four‐ and sixfold coordination, depending on the functionalized side chain. The stepwise elimination of the ligand from the complex observed by thermogravimetric analysis and the stability in solution are encouraging features for solution‐based processing of hematite thin films. As a representative example, compound 1 was successfully employed in a straightforward spin‐coating process. The fabricated iron oxide films were characterized in terms of their structure and phase by XRD and Raman spectroscopy, morphology by SEM, and composition by Rutherford backscattering spectrometry accompanied by nuclear reaction analysis, which revealed the formation of crystalline and stoichiometric α‐Fe2O3 films. [ABSTRACT FROM AUTHOR]

Abstract: It is very challenging to synthesize stable trivalent rare‐earth complexes in which the coordination number is lower than 3 for the high oxidation state, there is a large ion radius and nearly non‐bonding character of trivalent lanthanide ions. The bulky phenol ligand ArOH (Ar=2,6‐Dipp2C6H3, Dipp=2,6‐diisopropylphenyl) was utilized to construct low‐coordinate lanthanide compound [(ArO)Ln(OAr′)] (Ar′=6‐Dipp‐2‐(2′‐iPr‐6′‐CHMe(CH2−)C6H3)C6H3O−; Ln=Tb, Dy, Ho, Er, Tm). These complexes and the free ligand ArOH were isostructural. Magnetic measurements and theoretical studies demonstrated that both the oblate‐type dysprosium and prolate‐type erbium analogues exhibited single‐ion magnet (SIM) behavior. The bulky phenol ligands provided strong uniaxial ligand field, making the dysprosium SIM possessing blocking barrier up to 961 K. [ABSTRACT FROM AUTHOR]