Six new triorganotin(IV) carboxylates with the general formula (R or Ar) 3 SnL [where R or Ar = Me ( 1 , 4 ), Bu ( 2 , 5 ) and Ph ( 3 , 6 ) and L = (Z)-4-( p -toluidino)-4-oxobut-2-enoate (for complexes 1-3 ) and (Z)-4-(4-fluorophenylamino)-4-oxobut-2-enoate (for complexes 4- 6 )] are report herein. Solid state characterization [X-ray diffraction structural ( 1 , 2 and 4 ) analysis and FT-IR ( 1-6 )] unveiled the polymeric nature of the triorganotins imposed by a bridging coordination of a carboxylate ligand. Each Sn atom is five-coordinated with approximately trigonal bipyramidal geometry. However, in case of Me 3 SnL and Bu 3 SnL complexes, trigonal bipyramidal configuration switches to tetrahedral in solution, as evident by 1 H, 13 C and 119 Sn NMR. The structural, electronic and physicochemical properties of the compounds are explained using density functional theory at B3LYP/LANL2DZ level. The frontier molecular orbitals, Mulliken charge analyses and molecular electrostatic potential surfaces have been calculated to analyse the structure-property relationships (SARs) and physicochemical properties of complexes. Anticancer and noncancerous cells activities exposed the more active nature of complexes than the corresponding ligands. Furthermore, complexes have good antileshmanial and antioxidant activities.

The molecular structure of bis(2-isobutyrylamidophenyl)amine (H3LNNN) has been determined from single-crystal X-ray diffraction data. The crystal packing of H3LNNN is governed by the N-H···O and C-H···O hydrogen-bonding and C-H···π stacking interactions between the vicinal molecules. The intermolecular interactions in the crystal structure of H3LNNN have been also examined via Hirshfeld surface analysis and fingerprint plots. The Hirshfeld surface analysis showed that the important role of N-H···O and C-H···π interactions in the solid-state structure of H3LNNN. The molecular structure, vibrational frequencies, and infrared intensities of H3LNNN were computed by ab initio HF and DFT (B3LYP, B3PW91, and BLYP) methods using the 6-31G(d,p) basis set. The computed theoretical geometric parameters were compared with the corresponding single crystal structure of H3LNNN. The harmonic vibrations calculated for the title compound by the B3LYP method are in good agreement with the experimental IR spectral data. The theoretical vibrational spectrum of the H3LNNN compound was interpreted through potential energy distributions using the SQM Version 2.0 program. The performance of the used methods and the scaling factor values were calculated with PAVF Version 1.0 program.

Correction for ‘Mechanistic details of the cobalt-mediated dehydrogenative dimerization of aminoquinoline-directed benzamides’ by Li-Ping Xu et al., Chem. Sci., 2020, 11, 6085–6096, DOI: 10.1039/D0SC02066D.

The mechanism of catalytic allylic C–H amination reactions promoted by Cp*Rh complexes is reported. Reaction kinetics experiments, stoichiometric studies, and DFT calculations demonstrate that allylic C–H activation to generate a Cp*Rh(π-allyl) complex is viable under mild reaction conditions. The role of external oxidant in the catalytic cycle is elucidated. Quantum mechanical calculations, stoichiometric reactions, and cyclic voltammetryexperiments support an oxidatively induced reductive elimination process of the allyl fragment with an acetate ligand. Lastly, evidences supporting the amination of an allylic acetate intermediate is presented. Both nucleophilic substitution catalyzed by Ag+that behaves as a Lewis acid catalyst and an inner-sphere amination catalyzed by Cp*Rh are shown to be viable for the last step of the allylic amination reaction.

Four new triorganotin(IV) amide based carboxylates of general formula R3SnL1 and R3SnL2, where R = Me(1,3) and n-butyl (2,4), and L-1 = (Z) 4 (p methoxyphenylamino)-4-oxo-2-butenoic acid (HL1) L-2 = (Z)-4-(3,5-bis (trifluoromethyl)phenylamino)-4-oxo-2-butenoic acid (HL2) have been synthesized by refluxing methanolic solution of organtin(IV) chloride and ligand (1:1 M ratio). The synthesized compounds were characterized by FT-IR, elemental analysis, NMR (H-1, C-13, Sn-119 & F-19) and single crystal X-ray crystallography. The ligands co-ordinate to fin atom through oxygens (carboxylate and amide) showing distorted trigonal bipyramidal geometry with polymeric bridging behavior in solid state. However, the geometry is switched over from trigonal bipyramidal to tetrahedral upon dissolution as confirmed by multinuclear (H-1, C-13, F-19 and Sn-119) NMR. The prepared ligands and compounds 1-4 were screened for antimicrobial, antioxidant, cytotoxicity, hemolysis, antileishmanial and anticancer and noncancerous activities. The results showed significant antimicrobial activities, antioxidant, good cytotoxic LD50 values, percent hemolytic values, antileishmanial and anti-cancer activities. Compound 2 and 4 were found the most active antileishmanial and anticancer agent, respectively.

Key mechanistic features of the cobalt-mediated and aminoquinoline-directed dehydrogenative aryl-aryl coupling were investigated computationally and experimentally. A series of Co(II)and Co(III)complexes relevant to the proposed reaction cycle have been synthesized and characterized. Stoichiometric reactions and electrochemical studies were used to probe the role of different additives in the reaction pathway. Computationally, three different mechanisms, such ascharge neutral,anionic, anddimetallicwere explored. It is shown that the mono-metallicanionicandcharge neutralmechanisms are the most favorable ones, among which the former mechanism is slightly more encouraging and proceedsviathe: (a) concerted-metalation-deprotonation (CMD) of the first benzamide C-H bond, (b) PivOH-to-PivO(-)rearrangement, (c) CMD of the second benzamide C-H bond, (d) C-C coupling, (e) product formation facilitated by the amide nitrogen re-protonation, and (f) catalyst regeneration. The rate-determining step of this multi-step process is the C-C coupling step. The computational studies suggest that the electronics of both the aryl-benzamide and pyridine fragments of the aminoquinoline-benzamide ligand control the efficiency of the reaction.

Doctoral recipients in the biomedical sciences and STEM fields are showing increased interest in career opportunities beyond academic positions. While recent research has addressed the interests and preferences of doctoral trainees for non-academic careers, the strategies and resources that trainees use to prepare for a broad job market (non-academic) are poorly understood. The recent adaptation of the Social Cognitive Career Theory to explicitly highlight the interplay of contextual support mechanisms, individual career search efficacy, and self-adaptation of job search processes underscores the value of attention to this explicit career phase. Our research addresses the factors that affect the career search confidence and job search strategies of doctoral trainees with non-academic career interests and is based on nearly 900 respondents from an NIH-funded survey of doctoral students and postdoctoral fellows in the biomedical sciences at two U.S. universities. Using structural equation modeling, we find that trainees pursuing non-academic careers, and/or with low perceived program support for career goals, have lower career development and search process efficacy (CDSE), and receive different levels of support from their advisors/supervisors. We also find evidence of trainee adaptation driven by their career search efficacy, and not by career interests.

A dinuclear Co(ii) complex supported by a modular, tunable redox-active ligand system is capable of selective C–H amination to form indolines from aryl azides in good yields at low (1 mol%) catalyst loading.

Bimetallic (Et4N)2[Co2(L)2], (Et4N)2[1] (where (L)(3-) = (N(o-PhNC(O)(i)Pr)2)(3-)) reacts with 2 equiv of O2 to form the monometallic species (Et4N)[Co(L)O2], (Et4N)[3]. A crystallographically characterized analog (Et4N)2[Co(L)CN], (Et4N)2[2], gives insight into the structure of [3](1-). Magnetic measurements indicate [2](2-) to be an unusual high-spin Co(II)-cyano species (S = 3/2), while IR, EXAFS, and EPR spectroscopies indicate [3](1-) to be an end-on superoxide complex with an S = 1/2 ground state. By X-ray spectroscopy and calculations, [3](1-) features a high-spin Co(II) center; the net S = 1/2 spin state arises after the Co electrons couple to both the O2(•-) and the aminyl radical on redox non-innocent (L(•))(2-). Dianion [1](2-) shows both nucleophilic and electrophilic catalytic reactivity upon activation of O2 due to the presence of both a high-energy, filled O2(-) π* orbital and an empty low-lying O2(-) π* orbital in [3](1-).

Syntheses, structural, and spectroscopic characterization of multinuclear tris(amidate) lanthanide complexes is described. Addition of K3[N(o-PhNC(O)(t)Bu)3] to LnX3 (LnX3 = LaBr3, CeI3, and NdCl3) in N,N-dimethylformamide (DMF) results in the generation of dinuclear complexes, [Ln(N(o-PhNC(O)(t)Bu)3)(DMF)]2(μ-DMF) (Ln = La (1), Ce (2), Nd(3)), in good yields. Syntheses of tetranuclear complexes, [Ln(N(o-PhNC(O)(t)Bu)3)]4 (Ln = Ce (4), Nd(5)), resulted from protonolysis of Ln[N(SiMe3)2]3 (Ln = Ce, Nd) with N(o-PhNCH(O)(t)Bu)3. In the solid-state, complexes 1-5 exhibit coordination modes of the tripodal tris(amidate) ligand that are unique to the 4f elements and have not been previously observed in transition metal systems.