Redox Cycling with Tellurium. Si-H Bond Activation by a Lewis Superacidic Tellurenyl Cation.

The C,N-chelated aryltellurenyl triflate [2-(tBuNCH)CHTe][OTf] (1) activates the Si-H bonds in the tertiary silanes RSiH via umpolung of H to H to give rise to the iminium salts (tBuN(H)CH)CHTeSiR][OTf] (2, R=Et, Ph (elusive) and R=Si(CH) isolated; OTf=OSCF) comprising Te-Si bonds, which are capable of generating silyl triflates, RSiOTf, under attack of a second equivalent of 1. The unprecedented Si-H activation was utilized in main group redox catalysis using p-quinones, which were converted into (silylated) hydroquinones.

Antimony centre in three different roles: does donor strength or acceptor ability determine the bonding pattern?

A set of antimony(III) compounds containing a ligand (Ar) with a pendant guanidine function (where Ar = 2-[(MeN)CN]CH) was prepared and characterized. This includes triorgano-Ar3Sb, diorgano-Ar2SbCl and monoorgano-ArSbCl2 compounds and they were characterized by H and C NMR spectroscopy and by single-crystal X-ray diffraction analysis (sc-XRD). The coordination capability of Ar3Sb and Ar2SbCl was examined in the reactions with either -[PdCl(CHCN)] or PtCl and complexes -[(κ-Sb,N-Ar3Sb)MCl] (M = Pd 1, Pt 2) and [(κ-N,Sb,N-Ar2SbCl)MCl] (M = Pd 3, Pt 4) were isolated, while their structures were determined by sc-XRD.

Ruthenium Complexes with N-Bound 2-Pyridonato Ligand as O-Donors: A New Synthetic Approach and the Effect on Reactivity.

In this study, Ru complexes [(η-p-cymene)RuX(2-{(2,6-iPr-CH)N=CH}-CHN-6-(O))] (3: X=Cl; 4: X=I) were prepared with N-bound 2-pyridonato ligand by thermal base-free MeX elimination from ionic N,N-chelated Ru complexes [(η-p-cymene)RuX(κ-L)](X) (1: X=Cl; 2: X=I; L={2-[(2,6-iPr-CH)N=CH]-6-(OMe)CHN}). The Ru complex 3 was used as O-donor for Lewis (LA) or Brönsted acids. The reactions of 3 with SnCl, PhSnCl, ZnCl or HCl provided [(η-p-cymene)Ru(SnCl)(2-{(2,6-iPr-CH)N=CH}-CHN-6-(O→SnCl)] (6), [(η-p-cymene)RuCl(2-{(2,6-iPr-CH)N=CH}-CHN-6-(O→SnPhCl)] (7), and [(η-p-cymene)RuCl(2-{(2,6-iPr-CH)N=CH}-CHN-6-(O→)](μ-ZnCl) (8) and [(η-p-cymene)RuCl(2-{(2,6-iPr-CH)N=CH}-CHN-6-(OH)}](Cl) (9).

B-substituted group 1 phosphides: synthesis and reactivity.

1-Boryl-8-phosphinonaphthalenes 1-BCy-8-PCl-CH (1) and 1-BCy-8-PPhCl-CH (2) were prepared and used as starting materials for the synthesis of B-substituted phosphides. The reduction of 1 and 2 by Mg provided neutral compounds [1-BCy-8-PCy-CH] (3) and [1-BCy-8-PPh-CH] (4). Compound 3 represents the dimer of phosphinoborane 1-BCy-8-PCy-CH while complex 4 is a rare example of a discrete B ← P coordinated diphosphine.

Synthesis and reactivity of alkali metal aluminates bearing bis(organoamido)phosphane ligand.

In this study, we report a group of alkali metal aluminates bearing bis(organoamido)phosphane ligand. The starting complex {[PhP(NBu)]AlMe}Li·OEt (1) was prepared by stepwise deprotonation of the parent PhP(NHBu) by BuLi and AlMe. Further derivatization of aluminate 1 was performed by the virtual substitution of lithium -{[PhP(NBu)]AlMe}K (2), methyl substituents - {[PhP(NBu)]AlH}Li·THF (3), modification of steric bulk and induction effects on the phosphorus atom - {[BuP(-2,6-iPrCH)]AlMe}Li·(OEt) (4), and phosphorus atom oxidation state {[Ph(Y)P(NBu)]AlMe}Li (Y = O (5), S (6), Se (7), Te (8)).

Cyclopentadienyl Molybdenum(II) Compounds Bearing Ether and Thioether Functions in the Side Chain: Synthesis, Characterization, and Cytotoxic/Cytostatic Studies.

A series of molybdenum(II) compounds [(η -Cp')Mo(CO) (L )][BF ] (Cp'=C H (CH ) SPh, C H (CH ) OMe, L N,N-chelating ligand) have been synthesized and characterized by spectroscopic and analytical methods including X-ray crystallography. The in vitro assay on human leukemia cells MOLT-4 has shown that the substitution in the π-ligand in combination with suitable N,N-chelating ligand can lead to species with cytotoxicity considerably higher than reported to cisplatin. Unusually high activity was observed for compounds bearing phenanthroline ligands [{η -C H (CH ) OMe}Mo(CO) (3,4,7,8-Me phen)][BF ] (IC =0.

Stabilization of propene molybdenum and tungsten half-sandwich complexes by intramolecular coordination of a thioether function.

This study reports the stabilizing effect of an intramolecularly coordinated thioether function in propene complexes of the general formula [{η:κ-CH(CH)SR}M(CO)(η-CHMe)][BF] (M = Mo, W; R = Et, Ph). They are formed by protonation of allyl analogues [{η-CH(CH)SR}M(CO)(η-CH)] by tetrafluoroboric acid in non-coordinating solvents. In contrast to analogues with unsubstituted Cp ligands, these propene complexes are isolable in a pure form and characterized by NMR spectroscopy.

Tin(II) cations stabilized by non-symmetric N,N',O-chelating ligands: synthesis and stability.

A series of novel non-symmetric neutral N,N',O-chelating ligands derived from the α-iminopyridine 2-(C(R)N(CH-2,6-iPr))-6-(RRPO)CHN (L1: R = H, R = R = Ph; L2: R = Me, R = R = Ph; L3: R = H; R = Ph, R = EtO; L4: R = Me, R = Ph, R = EtO; L5: R = H, R = R = iPrO; L6: R1 = Me, R = R = iPrO) were synthesized. Ligands L1-6 were reacted with SnCl and Sn(OTf) with the aim of studying the influence of different RRPO functional groups on the Lewis base mediated ionization of SnCl and Sn(OTf). While all ligands L1-6 provided the corresponding ionic tin(II) complexes [L1-6 → SnCl][SnCl] (1-6), only ligands L1, L4 and L6 were able to stabilize tin(II) dications [L1,4,6 → Sn(HO)][OTf] (7-9).

The reactivity of antimony and bismuth ,,-pincer compounds toward K[BEtH] - the formation of heterocyclic compounds . element-element bonds stable terminal Sb-H bonds.

The oxidative addition of CFSOCHSi(CH) (NpOTf) toward organopnictogen(I) ,,-pincer compounds, [2,6-(DippNCH)CH]E (1-E, where E = Sb, Bi; Dipp = 2,6-iPrCH) produced compounds [2,6-(DippNCH)CH]E(Np)(OTf) (2-E, where E = Sb, Bi). By analogy, the reduction of [2,6-(MeNCH)CH]ECl (3-E, where E = Sb, Bi) followed by treatment with NpOTf or MeI gave compounds [2,6-(MeNCH)CH]E(R)(X) (R/X = Np/OTf 4-E, where E = Sb, Bi; R/X = Me/I 5-Sb). The reactivity of these compounds toward 1 eq.

Beyond simple hetero Diels-Alder cycloadditions. A new type of element-ligand cooperativity at N,C,N-coordinated arsinidene and stibinidene centres in the reaction with an electron-deficient alkyne.

The reactivity of two types of organopnictogen(I) N,C,N-pincer ligand coordinated compound, [2,6-(DippNCH)CH]E (1-E, where E = As, Sb, Bi; Dipp = 2,6-iPrCH) and [2-(DippNCH)-6-(DippNHCH)CH]E (6-E, where E = As or Sb), toward an electron-deficient alkyne, dimethyl acetylenedicarboxylate (DMAD), is reported. All reactions represent remarkable examples of element-ligand cooperation (ELC). In the first step, all compounds react dearomatization of a latent heteropnictole ring producing rare examples of hetero Diels-Alder (DA) adducts.

Reactivity of a N-Coordinated Germylene-Borane Complex: From Ge→B to Ge→Ga Coordination.

Reactivity studies of the Ge →B complex L(Cl)Ge⋅BH (1; L=2-Et NCH -4,6-tBu -C H ) were performed to determine the effect on the Ge →B donation. N-coordinated compounds L(OtBu)Ge⋅BH (2) and [LGe⋅BH ] (3) were prepared. The possible tuning of the Ge →B interaction was proved experimentally, yielding compounds 1-PPh -8-(LGe)-C H (4) and L(Cl)Ge⋅GaCl (5) without a Ge →B interaction.

,-coordinated Ru cation: a robust catalyst for aerobic oxidations of benzylamine and benzyl alcohol.

A stable ionic κ,-coordinated Ru complex shows excellent catalytic activity in aerobic oxidations of benzylamine and benzyl alcohol. This complex is stabilized by a stannylene-phosphine -substituted naphthalene ligand, which can act as either a reducing agent for a Ru(III) complex or as a κ,-chelating ligand for Ru(II) compounds.

Neuropathology Evaluation in Juvenile Toxicity Studies in Rodents: Comparison of Developmental Neurotoxicity Studies for Chemicals With Juvenile Animal Studies for Pediatric Pharmaceuticals.

The developmental neuropathology examination in juvenile toxicity studies depends on the nature of the product candidate, its intended use, and the exposure scenario (eg, dose, duration, and route). Expectations for sampling, processing, and evaluating neural tissues differ for developmental neurotoxicity studies (DNTS) for chemicals and juvenile animal studies (JAS) for pediatric pharmaceuticals. Juvenile toxicity studies typically include macroscopic observations, brain weights, and light microscopic evaluation of routine hematoxylin and eosin (H&E)-stained sections from major neural tissues (brain, spinal cord, and sciatic nerve) as neuropathology endpoints.

Lewis Superacidic Tellurenyl Cation-Induced Electrophilic Activation of an Inert Carborane.

The aryltellurenyl cation [2-(tBuNCH)C H Te] , a Lewis super acid, and the weakly coordinating carborane anion [CB H ] , an extremely weak Brønsted acid (pK =131.0 in MeCN), form an isolable ion pair complex [2-(tBuNCH)C H Te][CB H ], in which the Brønsted acidity (pK 7.4 in MeCN) of the formally hydridic B-H bonds is dramatically increased by more than 120 orders of magnitude.

Non-conventional Behavior of a 2,1-Benzazaphosphole: Heterodiene or Hidden Phosphinidene?

Invited for the cover of this issue are Zoltán Benkő, Libor Dostál and co-workers at the University of Pardubice and the Budapest University of Technology and Economics. The image depicts signs for the two different pathways representing the two differing reaction types which were clearly observed for 2,1-benzazaphosphole. Read the full text of the article at 10.

Prolonged antibiotic prophylaxis in tissue reconstruction using autologous fat grafting: Is there a benefit for wound healing?

Fat grafting is a well-established method in plastic surgery. Despite many technical advances, standardised recommendations for the use of prophylactic antibiotics in fat grafting are not available. This retrospective multicentre study aims to analyse the use of prophylactic antibiotics in fat grafting and to compare complication rates for different protocols.

Non-conventional Behavior of a 2,1-Benzazaphosphole: Heterodiene or Hidden Phosphinidene?

The titled 2,1-benzazaphosphole (1) (i. e. ArP, where Ar=2-(DippN=CH)C H , Dipp=2,6-iPr C H ) showed a spectacular reactivity behaving both as a reactive heterodiene in hetero-Diels-Alder (DA) reactions or as a hidden phosphinidene in the coordination toward selected transition metals (TMs).

Cyclopentadienyl-Based Anticancer Drugs: Improvement of Cytotoxic Activity through Functionalisation of the π Ligand.

Cytotoxic complexes containing molybdenum are widely studied as a potential substitution for commercially used drugs that often suffer from pronounced side effects and cellular resistance. Compounds of the type [(η -Cp')Mo(CO) ( L)][BF ], where Cp is cyclopentadienyl and L is a bidentate ligand, are well known for their strong anticancer activity. It is a generally accepted paradigm that the nature of the coordinated L ligand has a major impact on the cytotoxicity.

Sector Irradiation vs. Whole Brain Irradiation After Resection of Singular Brain Metastasis-A Prospective Randomized Monocentric Trial.

To minimize recurrence following resection of a cerebral metastasis, whole-brain irradiation therapy (WBRT) has been established as the adjuvant standard of care. With prolonged overall survival in cancer patients, deleterious effects of WBRT gain relevance. Sector irradiation (SR) aims to spare uninvolved brain tissue by applying the irradiation to the resection cavity and the tumor bed.

The prognostic value of Presepsin for postoperative complications following pancreatic resection: A prospective study.

Background: Presepsin is involved in binding lipopolysaccharides and previous studies have confirmed its value as a marker for early diagnosis and prediction of severity in sepsis. Comparable studies assessing the predictive potential regarding postoperative complications and mortality following pancreatic resection are lacking.

Methods: This prospective study included 70 patients undergoing pancreatic resection from December 2017 until May 2019.