We report magnetic penetration depth and thermal conductivity data for high-quality single crystals of BaFe$_2$(As$_{1-x}$P$_{x}$)$_2$ ($T_c=30$\,K) which provide strong evidence that this material has line nodes in its energy gap. This is distinctly different from the nodeless gap found (Ba,K)Fe$_2$As$_2$ similar $T_c$ phase diagram. Our results indicate repulsive electronic interactions play an essential role Fe-based high-$T_c$ superconductivity but uniquely there are pairing states, with...

Several recent efforts concerning post-metallocene Group 4 metal complexes incorporating mixed donor [OSSO]-type tetradentate bis(phenolato) ligands are reviewed. These can be mainly classified as 5–5–5, 5–6–5 and 6–5–6 arrays of chelate rings toward central metals. As the main topics described design unique coordination chemistry catalytic activities resultant titanium, zirconium, hafnium single-site catalysts for polymerizations copolymerizations olefins.

The first stable germabenzene (1a) bearing an efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, was successfully synthesized by the reaction of corresponding chlorogermane (4) with lithium diisopropylamide in THF. molecular structure and aromaticity 1a were discussed on basis its NMR, UV-vis, Raman spectra, X-ray crystallographic analysis, theoretical calculations. All (1)H (13)C NMR chemical shifts ring good agreement those calculated. UV-vis spectra showed...

Six-coordinated dibenzyl Zr complex bearing an [OSSO]-type tetradentate ligand was synthesized, and the structure fully characterized by NMR spectroscopy X-ray crystallography. The zirconium has C2 symmetry in solution. Owing to effect of cyclooctane ring structure, combination B(C6F5)3 or (Ph3C)[B(C6F5)4] as activator exhibited high activity toward polymerization 1-hexene yield highly isotactic poly(1-hexene).

A stable silicon-boron doubly bonded compound, silaborene (2), was synthesized by the reaction of 1,1-dilithiosilane (1) with dichloro(2,2,6,6-tetramethylpiperidino)borane in toluene. The X-ray crystallographic analysis 2 revealed that >Si=B-N< framework is almost linear (176.87(13) degrees ) an Si-B bond length 1.8379(17) A, which about 10% shorter than typical single bonds. reacted lithium trimethylsilylacetylide at 60 C DME to give corresponding silaborenide (4-.[Li(dme)3]+), whose...

The superconducting gap structure of LaFePO $({T}_{c}=7.4\text{ }\text{K})$ is studied by thermal conductivity $(\ensuremath{\kappa})$ at low temperatures in fields $H$ parallel and perpendicular to the $c$ axis. A clear two-step field dependence $\ensuremath{\kappa}(H)$ with a characteristic ${H}_{s}(\ensuremath{\sim}350\text{ }\text{Oe})$ much lower than upper critical ${H}_{c2}$ observed. In spite large anisotropy ${H}_{c2}$, both directions nearly identical below ${H}_{s}$. Above...

Treatment of trans-cyclooctanediyl-bridged [OSSO]-type ligand 1 with Hf(CH2Ph)4 in toluene afforded the corresponding hafnium(IV) dibenzyl complex 5 as pale yellow crystals. X-ray crystallographic analysis revealed that six-coordinated hafnium center incorporated adopted cis-α configuration, and two benzyl ligands were coordinated to by η1-fashion. In polymerization 1-hexene, combination B(C6F5)3, (Ph3C)[B(C6F5)4], or dMAO (dried methylaluminoxane) an activator provided poly(1-hexene)s...

A novel three-coordinated tin(II) chloride [Ph2P(NtBu)2]SnCl (1) supported by an N,N'-di-tert-butyliminophosphonamide having two phenyl groups on the phosphorus atom was synthesized reaction of starting lithium iminophosphonamide [Ph2P(NtBu)2]Li with SnCl2·(dioxane) in toluene. The molecular structure 1 established X-ray diffraction analysis. Tin(II) can act as efficient precatalyst for hydroboration a wide variety aldehydes, ketones, and imines at -10 °C. DFT calculations propose that...

We designed and synthesized a series of three‐coordinated stannylenes featuring an amino‐linked NHC ligand, specifically tailored for the hydroboration carbonyl compounds imines. To fine‐tune catalytic performance both sterically electronically, various substituents (chloro, triflate, bis(trimethylsilyl)amino groups) were introduced at tin center, generating structurally diverse stannylenes. The catalyzed by these proceeded under mild reaction conditions, affording corresponding boryl esters...

η6-Bonding characteristics are exhibited by stable germabenzene complexes that stabilized with the extremely bulky 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl ligand. The ring system coordinates to transition-metal centers (M=Cr, Mo; see picture) give first evidence of aromatic character in complexes, from standpoint their chemical reactivity.

The first stable hafnium-silylene complex, (eta-C5H4Et)2(PMe3)Hf=Si(SiMetBu2)2 (6) was obtained in the form of phosphine adduct as red crystals by coupling reaction 1,1-dilithiosilane (1) with 0.9 equiv (eta-C5H4Et)2HfCl2 dry toluene at -50 degrees C, followed treatment an excess PMe3 C. In 29Si NMR spectrum 6, signal from silylene ligand is shifted greatly downfield 295.4 ppm, a JSiP constant 15.0 Hz. X-ray crystallographic analysis 6 revealed that Si-Hf bond length (2.6515(9) A) about 5%...

Abstract The reaction of [PtH(SeTrip)(PPh 3 ) 2 ] (Trip = 9‐triptycyl) ( with dimethyl acetylenedicarboxylate (DMAD) or methyl propiolate gave hydroselenation syn adducts. [PtH(SeTrip)(dppe)] [dppe 1,2‐bis(diphenylphosphanyl)ethane], which has a stronger phosphane σ‐donor ligand than , DMAD both and anti in the presence PPh yielded no These observations indicate that, hydroselenation, dissociation from is key step. selenaplatinacycle 6 thermal product reacted to give carboselenation product,...

An isolable donor-stabilized silavinylidene phosphorane was synthesized. This molecule, which can also be regarded as a new carbon(0) complex featuring phosphine and silylene ligand, presents central carbon atom with remarkably high electron density (-1.82). Furthermore, the experimental electron-density study of this compound demonstrates delocalization σ-lone pair at toward silicon center, feature is different from electronic situation other bent-allene-type molecules. result clearly...

Abstract The N ‐heterocyclic silylene (NHSi) [Ph 2 P( t BuN) ]SiCl ( 1 ), supported by an iminophosphonamide ligand, was obtained from the dehydrochlorination of ]SiHCl ) with LiN(SiMe 3 . NHSi contains extremely high‐energy HOMO level and consequently displays unique coordination behavior toward Rh I complexes. When treated 1/4 equivalent [RhCl(cod)] (cod=1,5‐cyclooctadiene), 14‐electron Y‐shaped bis(chlorosilylene) complex 5 as dark purple crystals. reaction 1/6 yielded cationic...

Abstract A novel N‐hetero‐Rh I ‐metallacyclic silanone 2 has been synthesized. The , showing an extremely large dimerization energy (Δ G =+86.2 kcal mol −1 ), displays considerable stability and persists in solution up to 60 °C. Above 120 °C, intramolecular C sp3 −H insertion occurs slowly over a period of two weeks leading the bicyclic silanol 5 . exceptional related unusual electronic steric effects Rh ‐substituent, should allow for more profound study understanding these new species....

Abstract 1,1-Dilithiosilane and -germane, R2SiLi2 R2GeLi2 (R = SiMetBu2) reacted with MesBCl2 to give the unexpected seven-membered ring products, [1,3,2]oxasila- -germaborepanes, through intermediate formation of &amp;gt;Si=B– &amp;gt;Ge=B– doubly bonded species.

A selenaplatinacycle (see structure 1; red P, blue Pt, green Se) is formed by the reactions of TripSe(O)SeTrip (Trip = 9-triptycyl) and TripSeOH with [Pt(PPh3)2(η2-C2H4)] intramolecular CH activation leading to cyclometalation. The reaction TripSeSeTrip also provided 1 together TripSeH, which reacts give hydrido selenolato platinum(II) complex 2.

The first examples of palladium(II) hydrido complexes having a dihydrosilyl or dihydrogermyl ligand, [PdH(EH2Trip)(dcpe)] (E = Si (2), Ge (4); dcpe 1,2-bis(dicyclohexylphosphino)ethane), were synthesized by oxidative addition an overcrowded primary silane and germane, TripEH3 (1), (3); Trip 9-triptycyl) with [(μ-dcpe)Pd]2 in toluene. molecular structures 2 4 established single-crystal X-ray analysis, which showed distorted-square-planar geometry around the palladium centers, probably due to...

trans-Cyclooctanediyl-bridged [OSSO]-type ligand 4 reacts with TiCl(4)(thf)(2) in toluene to produce the corresponding titanium(IV) dichloro complexes as an inseparable mixture of cis-α isomer 6a and cis-β 6b a ratio 2:1, whereas treatment dilithio salt TiCl(3)(thf)(3) Et(2)O afforded chloride-bridged dimeric titanium(III) complex 8, which indicated antiferromagnetic character nonpolar solvent solution. Di(isopropoxy) 10 having C(2)-symmetric configuration was synthesized by reaction...

Group 5 metal complexes bearing an [OSSO]-type bis(phenolate) ligand have been successfully prepared by the reaction of a bis(phenol) compound 3 or its dilithio salt 6 with VO(OPr)3, NbCl5, TaCl5. X-ray crystallographic analyses revealed monomeric nature resulting complexes, [OSSO]VO(OPr) (5), [OSSO]NbCl3 (7), and [OSSO]TaCl3 (8), where centers adopted cis-α configurations [OSSO] tetradentate ligand. The tantalum(V) complex 8 iBu3Al/(Ph3C)[B(C6F5)4] as activator catalyzed polymerization...

Keen to donate: A stable and isolable silene with two π-donating groups on the silicon center has been synthesized. This silicon-substituted shows totally different π-substituent effects compared those of related carbon-substituted silenes, it presents intrinsic properties an enhanced electron-donating character, making excellent ligand for transition metals.

[OSSO]-type dibenzyl zirconium(IV) complexes 9 and 10 possessing aryl substituents ortho to the phenoxide moieties (ortho substituents, phenyl 2,6-dimethylphenyl (Dmp)) were synthesized characterized. Upon activation with dMAO (dried methylaluminoxane), complex was found promote highly isospecific styrene polymerizations ([mm] = 97.5%–99%) high molecular weights Mw up 181,000 g·mmol−1. When Dmp-substituted pre-catalyst 10/dMAO system used, highest activity, over 7700 g·mmol(10)−1·h−1,...

Abstract A cyclic (amino)metal‐substituted dicoordinated silylene derivative has been synthesized and fully characterized. Of particular interest is that the N‐hetero‐Rh I ‐metallacyclic exhibits a distorted tetrahedral geometry around rhodium atom considerably shortened Si−Rh bond (2.138 Å) compared to classical single bonds (ca. 2.30–2.35 Å). theoretical investigation reveals geometrical deviation center from square‐planar increases π‐donating σ‐accepting character of atom, thereby...