Tris Research Articles

Synthesis, Structure and Magnetic Behavior of a Novel Series of Trinuclear Windwheel Complexes

Comprehensive SummaryA new family of trinuclear windwheel complexes with molecular formula [MII3(tpa)3(μ‐ttc)](ClO4)3·n(sol) (ttc = 1,3,5‐triazine‐2,4,6‐trithiol; tpa = tris(2‐pyridylmethyl)amine; M = Mn, n = 2, sol = CH3CN, 1; M = Co, n = 1, sol = CH3CN, 2; M = Ni, n = 0, 3) were synthesized and characterized. Single‐crystal X‐ray diffraction revealed that three metal centers in 1—3 are connected by ttc bridge, forming a regular triangular MII3 core. Each metal center is bonded by chelating S, N atoms from ttc and by N atoms from tpa. Magnetic studies showed that 1—3 displayed antiferromagnetic behavior and further gave the easy‐axis anisotropy (D = −0.77 cm−1 for 1 and −8.13 cm−1 for 2) and easy‐plane anisotropy (D = 5.08 cm−1 for 3). Moreover, 2 exhibited field‐induced slow magnetic relaxation behavior and their effective energy barriers were roughly evaluated Ueff = 6.9 K.

Four Decades of the Comet Assay: pH Optimum of Lysis Buffer Still Needs to be Elucidated.

The proper course and reproducibility of diagnostic techniques depend on narrowly defined reaction conditions, including the reaction pH. Nevertheless, numerous assays are affected by an inaccurately defined reaction pH. Buffers are sometimes suggested for use outside their useful pH ranges, which complicates the reproducibility of results because the buffering capacity is insufficient to retain the disclosed pH. Here, we focus on the comet assay lysis buffer. Comet assay is broadly used for quantifying DNA breaks in eukaryotic cells. The most widespread comet assay protocols employ lysis of the cells before electrophoresis in a buffer containing Triton X-100, a high concentration of NaCl, sodium sarcosinate, EDTA, and Tris, with some modifications. However, nearly all researchers report that they use Tris buffer at pH 10, and some report the pH of the Tris additive alone. Alternatively, others report the pH of the final lysis buffer. However, the lysis solution used in the comet assay is buffered at a pH outside the useful range of Tris. Tris-based buffers have a useful pH range of 7.0 - 9.0. The buffer composed of 10 mM Tris has pKa 8.10 at 25°C and 8.69 at 4°C. The cell lysis conditions used in nearly all modifications of comet assay protocols remain imprecise and uncritically employed. Despite the pH of the lysis buffer likely has negligible effect on the detection of DNA breaks, precise lysis conditions are highly important for the use of comet assay in the detection of base modifications, which are often unstable and sensitive to pH.

The Effect of Mixed Ligands on the Polymerization Rate of SET-LRP in Aqueous Solution

Abstract The mixed-ligand effect is investigated in single electron transfer-living radical polymerization (SET-LRP) of OEOMA in aqueous solution for the first time. Mediated by equimolar tris(2-aminoethyl)amine (TREN) and tris(dimethylaminoethyl)amine (Me6-TREN), SET-LRP exhibits the highest polymerization rate while maintaining living characteristics. The higher concentration of self-assembled micellar particles formed by amphiphilic initiator and monomer in aqueous solution under the influence of mixed ligands may be considered as one of factors for the mixed-ligand effect.

N-Acetylcysteine Displaces Glutathionyl-Moieties from Hg2+ and MeHg+ to Form More Hydrophobic Complexes at Near-Physiological Conditions.

The anthropogenic release of Hg is associated with an increased human exposure risk. Since Hg2+ and MeHg+ have a high affinity for thiols, their interaction with L-glutathione (GSH) within mammalian cells is fundamentally involved in their toxicological chemistry and excretion. To gain insight into the interaction of these mercurials with multiple small molecular weight thiols, we have investigated their competitive interactions with GSH and N-acetylcysteine (NAC) at near-physiological conditions, using a liquid chromatographic approach. This approach involved the injection of each mercurial onto a reversed-phase (RP)-HPLC column (37 °C) using a PBS buffer mobile phase containing 5.0 mM GSH to simulate cytosolic conditions with Hg being detected in the column effluent by an inductively coupled plasma atomic emission spectrometer (ICP-AES). When the 5.0 mM GSH mobile phase was amended with up to 10 mM NAC, gradually increasing retention times of both mercurials were observed. To explain this behavior, the experiment with 5.0 mM NAC and 5.0 mM GSH was replicated using 50 mM Tris buffer (pH 7.4), and the Hg-containing fractions were analyzed by electrospray ionization mass spectrometry. The results revealed the presence of Hg(GS)(NAC) and Hg(NAC)2 for Hg2+ and MeHg(GS) and MeHg(NAC) for MeHg+, which suggests that the coordination/displacement of GS-moieties from each mercurial by the more hydrophobic NAC can explain their retention behavior. Since the biotransformations of both mercurials were observed at near-physiological conditions, they are of toxicological relevance as they provide a biomolecular explanation for some results that were obtained when animals were administered with each mercurial and NAC.

Identification and characterisation of a major outer membrane protein from Methylacidiphilum fumariolicum SolV

The outer membrane (OM) protects Gram-negative bacteria against a hostile environment. The proteins embedded in the OM fulfil a number of tasks that are crucial to the bacterial cell. In this study, we identified and characterised a major outer membrane protein (WP_009059494) from Methylacidiphilum fumariolicum SolV. PRED-TMBB and AlphaFold2 predicted this protein to form a porin with a β-barrel structure consisting of ten antiparallel β-sheets and with a small amphipathic N-terminal α-helix in the periplasm. We purified soluble recombinant protein WP_009059494 from E. coli using Tris–HCl buffer with SDS. Antibodies were raised against two peptides in the two large extracellular loops of protein WP_009059494 and immunogold localisation showed this protein to be mainly present in the OM of strain SolV. In addition, this protein is tightly associated with the OM, and is resistant to extraction. Only a small amount can be isolated from the cell envelope using harsh conditions (SDS and boiling). Despite this resistance to extraction, WP_009059494 most likely is an outer membrane protein. A regular lattice could not be detected by negative staining TEM of strain SolV and isolated protein WP_009059494. Considering the specific ecological niche of strain SolV living in a geothermal environment with low pH and high temperatures, this major protein WP_009059494 may act as barrier to resist the extreme conditions found in its natural environment. In addition, we found an absence of the BamB, BamC and BamE proteins of the canonical BAM complex, in Methylacidiphilum and Methylacidimicrobium species. This suggests that these bacteria use a simple BAM complex for folding and transport of OM proteins.

Epoxy SQ-based amine functionalized superhydrophilic hybrid network for Ag+ adsorption and catalytic degradation of Rhodamine B

Most epoxy substituted silsesquioxane (SQ)-based materials are hydrophobic, it is of great interest to develop hydrophilic epoxy SQ-based materials for special applications. In this work, epoxy functionalized SQ with T10 (G-SQ) as main product was obtained by the hydrolytic condensation of 3-(glycidoxypropyl)trimethoxysilane; then the hybrid network of G-SQ-TAEA was produced by the amine-epoxy click reaction of G-SQ with tris(2-aminoethyl)amine (TAEA). The introduction of hydroxyl groups and the amine groups by the amine-epoxy click reaction greatly enhances the hydrophilicity of the hybrid network and facilitates the dispersion of G-SQ-TAEA in water. Interestingly, G-SQ-TAEA can adsorb Ag+ ions with a saturation capacity of 86.4 mg/g and the Ag-loaded G-SQ-TAEA (G-SQ-TAEA-Ag) can efficiently catalyze degradation of Rhodamine B (RhB) to colourless. This work offers a new strategy for removing contamination in water.

Controlling Spin Crossover in a Family of Dinuclear Fe(III) Complexes via the Bis(catecholate) Bridging Ligand.

Spin crossover (SCO) complexes can reversibly switch between low spin (LS) and high spin (HS) states, affording possible applications in sensing, displays, and molecular electronics. Dinuclear SCO complexes with access to [LS-LS], [LS-HS], and [HS-HS] states may offer increased levels of functionality. The nature of the SCO interconversion in dinuclear complexes is influenced by the local electronic environment. We report the synthesis and characterization of [{FeIII(tpa)}2spiro](PF6)2 (1), [{FeIII(tpa)}2Br4spiro](PF6)2 (2), and [{FeIII(tpa)}2thea](PF6)2 (3) (tpa = tris(2-pyridylmethyl)amine, spiroH4 = 3,3,3',3'-tetramethyl-1,1'-spirobi(indan)-5,5',6,6'-tetraol, Br4spiroH4 = 3,3,3',3'-tetramethyl-1,1'-spirobi(indan)-4,4',7,7'-tetrabromo-5,5',6,6'-tetraol, theaH4 = 2,3,6,7-tetrahydroxy-9,10-dimethyl-9,10-dihydro-9,10-ethanoanthracene), utilizing non-conjugated bis(catecholate) bridging ligands. In the solid state, magnetic and structural analysis shows that 1 remains in the [HS-HS] state, while 2 and 3 undergo a partial SCO interconversion upon cooling from room temperature involving the mixed [LS-HS] state. In solution, all complexes undergo SCO from [HS-HS] at room temperature, via [LS-HS] to mixtures including [LS-LS] at 77 K, with the extent of SCO increasing in the order 1 < 2 < 3. Gas phase density functional theory calculations suggest a [LS-LS] ground state for all complexes, with the [LS-HS] and [HS-HS] states successively destabilized. The relative energy separations indicate that ligand field strength increases following spiro4- < Br4spiro4- < thea4-, consistent with solid-state magnetic and EPR behavior. All three complexes show stabilization of the [LS-HS] state in relation to the midpoint energy between [LS-LS] and [HS-HS]. The relative stability of the [LS-HS] state increases with increasing ligand field strength of the bis(catecholate) bridging ligand in the order 1 < 2 < 3. The bromo substituents of Br4spiro4- increase the ligand field strength relative to spiro4-, while the stronger ligand field provided by thea4- arises from extension of the overlapping π-orbital system across the two catecholate units. This study highlights how SCO behavior in dinuclear complexes can be modulated by the bridging ligand, providing useful insights for the design of molecules that can be interconverted between more than two states.

Coordination of ε-Caprolactone to a Cationic Niobium(V) Alkoxide Complex: Fundamental Insight into Ring-Opening Polymerization via Coordination-Insertion.

We report three niobium-based initiators for the catalytic ring-opening polymerization (ROP) of ε-caprolactone, exhibiting good activity and molecular weight control. In particular, we have prepared on the gram-scale and fully characterized a monometallic cationic alkoxo-Nb(V) ε-caprolactone adduct representing, to the best of our knowledge, an unprecedented example of a metal complex with an intact lactone monomer and a functional ROP-initiating group simultaneously coordinated at the metal center. At 80 °C, all three systems initiate the immortal solution-state ROP of ε-caprolactone via a coordination-insertion mechanism, which has been confirmed through experimental studies, and is supported by computational data. Natural bond orbital calculations further indicate that polymerization may necessitate isomerization about the metal center between the alkoxide chain and the coordinated monomer. The observations made in this work are expected to inform mechanistic understanding both of amine tris(phenolate)-supported metal alkoxide ROP initiators, including various highly stereoselective systems for the polymerization of lactides and of coordination-insertion-type ROP protocols more broadly.

Structural and in vitro biological properties of strontium substituted bio-waste derived wollastonite for bone regeneration

Strontium (Sr) substituted wollastonite bioceramics were prepared by a modified sol-gel technique using bio-wastes such as eggshell as calcium oxide source and rice husk as silica source. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) were used to perform structural analysis. Bioactivity was examined by testing the apatite mineralization ability in vitro by immersing the ceramic pellets in simulated body fluid (SBF) for various time periods. Degradation assay was performed in Tris buffer solutions by following the protocol in ISO 10993-14 standard. Cytocompatibility and cell proliferation were analyzed at different concentrations using osteoblast like MG 63 cells by MTT assay. The results show that the addition of Sr increases the density and mechanical properties of wollastonite but decreases with SrO above 2.5 mol.%. Pure and Sr containing wollastonite possessed excellent apatite formation ability with continuous degradation under physiological conditions. The results of cell culture studies revealed that all prepared ceramics were non-toxic to osteoblast-like cells at different doses (0–1000 μg/mL), and wollastonite ceramics containing Sr also enhanced cell proliferation.

The morphology, morphometry and functionality of fresh and cryopreserved wisent (Bison bonasus) epididymal spermatozoa

Epididymal spermatozoa obtained post mortem are considered a valuable source of genetic material which is often irrevocably lost. This makes these gametes constitute a key element in protection and restitution programs. The wisent (Bison bonasus, Linnaeus 1758) is a species that survived in zoos after extinction from its natural habitat. This resulted in a narrowing of the genetic pool of the whole population, which is at present derived from only 12 ancestors. Currently, wisent protection programs are aimed at preserving the genetic diversity by establishing a germplasm bank. The objective of this study was to comprehensively characterize the morphology, morphometry and functionality of wisent epididymal spermatozoa and evaluate the effectiveness of their cryopreservation in extender based on Tris buffer and chicken egg yolk. The median total number of spermatozoa obtained from one individual was 1985.0 × 106 (62.5 × 106–7452.0 × 106). These gametes were characterized by median: 40.0% (0.5–70.0%) subjective motility, 69.8% (32.5–90.0%) viability and 54.3% (10.5–83.3%) normal morphology. The sperm head had a median size of 5.0 μm (3.5–6.7 μm) width, 8.5 μm (6.4–11.3 μm) length and 36.9 μm2 (23.7–48.6 μm2) surface area. The viable population of the obtained gametes was characterized by median values 53.2% (4.5–80.3%) of intact sperm membrane, 50.8 (26.0–76.6%) of intact acrosome, 0.4% (0–98.7%) of fragmented chromatin, 5.9% (0.0–88.8%) of cells with high mitochondrial potential and 42.1% (8.3–63.7%) without lipid peroxidation. The viable population of the frozen/thawed gametes was characterized by median values: 18.4% (2.4–57.9%) of intact sperm membrane, 35.1 (11.9–56.7%) of intact acrosome, 0.07% (0–89.2%) of fragmented chromatin, 12.8% (0.0–49.7%) of cells with high mitochondrial potential and 16.3% (2.2–53.6%) without lipid peroxidation. Due to the material originating from a relatively large number of wild individuals, the research presented here contributed to the description of certain species standards for the assessment of wisent epididymal spermatozoa. The presented effect of cryopreservation on these gametes justifies the use of an extender based on Tris buffer with the addition of chicken egg yolk. The obtained effects are satisfactory from the point of view of preserving valuable genetic material and their use in ART.

Effective adsorption of thorium ion by novel self-crosslinking polyamide acid-grafted magnetic nanocomposites

A novel self-crosslinking polymer-coated magnetic nanosorbent (Fe3O4@PAA) was prepared to remove thorium ions from aqueous solutions. The grafting-polymerization method was employed to graft polyamide acid (PAA) onto amino-activated magnetic nanoparticles (Fe3O4@SiO2-NH2) via an amidation reaction using pyromellitic dianhydride (PMDA) and tris(2-aminoethyl)amine (TA) as monomers. The adsorption results show that the adsorption process of Th(IV) by Fe3O4@PAA is significantly pH-sensitive, and the theoretical maximum adsorption capacity can reach 122.5 mg/g at pH 3.0. Furthermore, Fe3O4@PAA exhibits a high adsorption rate and the adsorption equilibrium could be reached within 60 min. After 5 cycles of reuse, the adsorption capacity was still retained at more than 80 % of the initial value. In addition, the extraction mechanism of Fe3O4@PAA for Th (IV) ions was analyzed in detail by FT-IR and XPS. This work provides valuable insights into the design and preparation of novel, acid-resistant, easily separable and fast magnetic separation adsorbents for the highly effective separation of Th () from aqueous solutions.

Bovine Serum Albumin Molecularly Imprinted Electrochemical Sensors Modified by Carboxylated Multi-Walled Carbon Nanotubes/CaAlg Hydrogels.

In this paper, sodium alginate (NaAlg) was used as functional monomers, bovine serum albumin (BSA) was used as template molecules, and calcium chloride (CaCl2) aqueous solution was used as a cross-linking agent to prepare BSA molecularly imprinted carboxylated multi-wall carbon nanotubes (CMWCNT)/CaAlg hydrogel films (MIPs) and non-imprinted hydrogel films (NIPs). The adsorption capacity of the MIP film for BSA was 27.23 mg/g and the imprinting efficiency was 2.73. The MIP and NIP hydrogel film were loaded on the surface of the printed electrode, and electrochemical performance tests were carried out by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) using the electrochemical workstation. The loaded MIP film and NIP film effectively improved the electrochemical signal of the bare carbon electrode. When the pH value of the Tris HCl elution solution was 7.4, the elution time was 15 min and the adsorption time was 15 min, and the peak currents of MIP-modified electrodes and NIP-modified electrodes reached their maximum values. There was a specific interaction between MIP-modified electrodes and BSA, exhibiting specific recognition for BSA. In addition, the MIP-modified electrodes had good anti-interference, reusability, stability, and reproducibility. The detection limit (LOD) was 5.6 × 10-6 mg mL-1.

Nitrogen-rich, click-based porous organic polymers featuring flexible amine cores for catalytic CO2/epoxide cycloaddition

CO2 utilization to produce value-added products such as cyclic carbonates, especially under mild catalytic conditions, is a promising strategy to reduce CO2 emissions to the environment. In this work, nitrogen-rich, click-based porous polymers (CPPs) were prepared from coupling of tripropargylamine and rigid diazido aromatic substrates, featuring 1,4-phenylene (TB), 1,5-naphthalene (TN), and 4,4′-benzanilide (TBA) linkers, in moderate to good yields (48–83%) using Cu-catalyzed azide–alkyne cycloaddition (CuAAC; TB-C, TN-C, TBA-C) and Huisgen cycloaddition (TB-H, TN-H, and TBA-H). The presence of the chelate tris(triazolylmethyl)amine ligands within the polymer's structure led to strong copper binding and consequently high copper loading ability of the CPPs. In addition, high contents of Lewis basic N donors (21–27 wt% N) of TB-C, TN-C, TBA-C are most likely attributed to strong interactions between CO2 and CPPs and exceptionally high CO2 selectivity over N2 at 273 K, based on gas sorption studies. The catalyst system TB-C/TBAB (TBAB = tetrabutylammonium bromide) promoted complete conversion of epoxides to cyclic carbonates under an atmospheric CO2 pressure, after 24 h or 48 h at 100 °C, with the exception of the epichlorohydrin substrate where 42% selectivity was observed by 1H NMR spectroscopy. The TB-C/TBAB catalyst system could be reused for five catalytic runs without a loss in catalytic activities and any pre-activation processes.

Complexes of Cu(II), Co(II), and Zn(II) Terephthalates with Hydroxyalkylamines

The reactions of Cu(II), Co(II), and Zn(II) terephthalates with hydroxyalkylamines (tris(2-hydroxyethyl)amine, bis(2-hydroxyethyl)amine, tris(hydroxymethyl)aminomethane, and bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane) are studied for the first time. The structures and properties of the synthesized complexes are studied by IR spectroscopy, electronic absorption spectroscopy, mass spectrometry, and elemental and thermal analyses. The structure of the binuclear heteroligand [Cu2(TEA)2(Tph)]n·H2O complex is studied by single-crystal X-ray diffraction (XRD) (CIF file CCDC no. 2224437).

Highly elastic and degradable vitrimeric elastomers using polycondensation

Introducing covalently crosslinked network to polymer matrix can merge the advantages in reprocessing and durability of polymers. In this contribution, a series of high-performance vitrimeric elastomers were achieved via polycondensation. The topological structures of polymers were tuned by varying the feeding ratios of bisacetoacetate, hex‑substituted bisacetoacetate, bisamine and tris(2-aminoethyl)amine. With these structural manipulations, the vitrimeric elastomers presented great elastic recovery properties (strain recovery value up to 80%) benefiting from the introduction of long chain branch. Furthermore, the elastomers exhibited excellent reprocessing property, water vapor/oxygen barrier and adhesive properties. Specially, the elastomers could be degraded into monomer under acid conditions which enabled the elastomer synthesis again in closed loop recycling system. The ease of the polycondensation in this work to prepare highly elastic and recyclable vitrimeric elastomers demonstrated exciting opportunities for the synthesis of sustainable polymers.

Highly Selective Turn-on Fluorescence Sensor for Cd2+ Ions by TripodalOrganic Ligand.

Organic fluorescence sensor for selectively detecting and quantifying toxic heavy metal ions has received significant interest due to their environmental hazards. Herein, we have designed and synthesized a simple tripodal Schiff base ligand (1) based on hydroxy-naphthaldehyde and tris(2-aminoethyl)amine (TREN) and demonstrated highly selective turn-on fluorescence sensing of Cd2+ ions. The free ligand did not show any fluorescence in DMF. In contrast, Cd2+ (10- 4M) addition exhibited a strong enhancement of fluorescence at 450nm. Interestingly, other metal ions including Zn2+, which exhibit similar chemistry, did not show any turn-on fluorescence. The concentration-dependent studies of 1 with Cd2+ showed the detection limit of 6.78 × 10- 8M. NMR spectra of 1 with Cd2+ and computational studies were performed to understand the mechanism of sense.

Closed-loop Recycling of Vinylogous Urethane Vitrimers.

Devising energy-efficient strategies for the depolymerization of plastics and the recovery of their structural components in high yield and purity is key to a circular plastics economy. Here, we report a case study in which we demonstrate that vinylogous urethane (VU) vitrimers synthesized from bis-polyethylene glycol acetoacetates (aPEG) and tris(2-aminoethyl)amine can be degraded by water at moderate temperature with almost quantitative recovery (~98%) of aPEG. The rate of depolymerization can be controlled by the temperature, amount of water, molecular weight of aPEG, and composition of the starting material. These last two parameters also allow one to tailor the mechanical properties of the final materials, and this was used to access soft, tough, and brittle vitrimers, respectively. The straightforward preparation and depolymerization of the aPEG-based VU vitrimers are interesting elements for the design of polymer materials with enhanced closed-loop recycling characteristics.

Closed‐Loop Recycling of Vinylogous Urethane Vitrimers

AbstractDevising energy‐efficient strategies for the depolymerization of plastics and the recovery of their structural components in high yield and purity is key to a circular plastics economy. Here, we report a case study in which we demonstrate that vinylogous urethane (VU) vitrimers synthesized from bis‐polyethylene glycol acetoacetates (aPEG) and tris(2‐aminoethyl)amine can be degraded by water at moderate temperature with almost quantitative recovery (≈98 %) of aPEG. The rate of depolymerization can be controlled by the temperature, amount of water, molecular weight of aPEG, and composition of the starting material. These last two parameters also allow one to tailor the mechanical properties of the final materials, and this was used to access soft, tough, and brittle vitrimers, respectively. The straightforward preparation and depolymerization of the aPEG‐based VU vitrimers are interesting elements for the design of polymer materials with enhanced closed‐loop recycling characteristics.

Trapping an Ester Hydrate Intermediate in a π-Stacked Macrocycle with Multiple Hydrogen Bonds.

Ester hydrates, as the intermediates of the esterification between acid and alcohol, are very short-lived and challenging to be trapped. Therefore, the crystal structures of ester hydrates have rarely been characterized. Herein, we present that the mono-deprotonated ester hydrates [CH3OSO2(OH)2]-, serving as the template for the self-assembly of a π-stacked boat-shaped macrocycle (CH3OSO2(OH)2)0.67(CH3OSO3)1.33@{[ClLCoII]6}·Cl4·13CH3OH·9H2O (1) (L = tris(2-benzimidazolylmethyl) amine), can be trapped in the host by multiple NH···O hydrogen bonds. In the solution of CoCl2, L, and H2SO4 in MeOH, HSO4- reacts with MeOH, producing [CH3OSO3]- via the ester hydrate intermediate of [CH3OSO3(OH)2]-. Both the product and the intermediate serve as the template directing the self-assembly of the π-stacked macrocycle, in which the short-lived ester hydrate is firmly trapped and stabilized, as revealed by single-crystal analysis.

Poly(2-oxazoline)-Based Polyplexes as a PEG-Free Plasmid DNA Delivery Platform.

The present study expands the versatility of cationic poly(2-oxazoline) (POx) copolymers as a polyethylene glycol (PEG)-free platform for gene delivery to immune cells, such as monocytes and macrophages. Several block copolymers are developed by varying nonionic hydrophilic blocks (poly(2-methyl-2-oxazoline) (pMeOx) or poly(2-ethyl-2-oxazoline) (pEtOx), cationic blocks, and an optional hydrophobic block (poly(2-isopropyl-2-oxazoline) (iPrOx). The cationic blocks are produced by side chain modification of 2-methoxy-carboxyethyl-2-oxazoline (MestOx) block precursor with diethylenetriamine (DET) or tris(2-aminoethyl)amine (TREN). For the attachment of a targeting ligand, mannose, azide-alkyne cycloaddition click chemistry methods are employed. Of the two cationic side chains, polyplexes made with DET-containing copolymers transfect macrophages significantly better than those made with TREN-based copolymer. Likewise, nontargeted pEtOx-based diblock copolymer is more active in cell transfection than pMeOx-based copolymer. The triblock copolymer with hydrophobic block iPrOx performs poorly compared to the diblock copolymer which lacks this additional block. Surprisingly, attachment of a mannose ligand to either copolymer is inhibitory for transfection. Despite similarities in size and design, mannosylated polyplexes result in lower cell internalization compared to nonmannosylated polyplexes. Thus, PEG-free, nontargeted DET-, and pEtOx-based diblock copolymer outperforms other studied structures in the transfection of macrophages and displays transfection levels comparable to GeneJuice, a commercial nonlipid transfection reagent.