Normal Experimental Conditions Research Articles

Progress in Nonaqueous Molecular Uranium Chemistry: Where to Next?

There is long-standing interest in nonaqueous uranium chemistry because of fundamental questions about uranium's variable chemical bonding and the similarities of this pseudo-Group 6 element to its congener d-block elements molybdenum and tungsten. To provide historical context, with reference to a conference presentation slide presented around 1988 that advanced a defining collection of top targets, and the challenge, for synthetic actinide chemistry to realize in isolable complexes under normal experimental conditions, this Viewpoint surveys progress against those targets, including (i) CO and related π-acid ligand complexes, (ii) alkylidenes, carbynes, and carbidos, (iii) imidos and terminal nitrides, (iv) homoleptic polyalkyls, -alkoxides, and -aryloxides, (v) uranium-uranium bonds, and (vi) examples of topics that can be regarded as branching out in parallel from the leading targets. Having summarized advances from the past four decades, opportunities to build on that progress, and hence possible future directions for the field, are highlighted. The wealth and diversity of uranium chemistry that is described emphasizes the importance of ligand-metal complementarity in developing exciting new chemistry that builds our knowledge and understanding of elements in a relativistic regime.

Thorium(IV)-antimony complexes exhibiting single, double, and triple polar covalent metal-metal bonds.

There is continued burgeoning interest in metal-metal multiple bonding to further our understanding of chemical bonding across the periodic table. However, although polar covalent metal-metal multiple bonding is well known for the d and p blocks, it is relatively underdeveloped for actinides. Homometallic examples are found in spectroscopic or fullerene-confined species, and heterometallic variants exhibiting a polar covalent σ bond supplemented by up to two dative π bonds are more prevalent. Hence, securing polar covalent actinide double and triple metal-metal bonds under normal experimental conditions has been a fundamental target. Here we exploit the protonolysis and dehydrocoupling chemistry of the parent dihydrogen-antimonide anion, to report one-, two- and three-fold thorium-antimony bonds, thus introducing polar covalent actinide-metal multiple bonding under normal experimental conditions between some of the heaviest ions in the periodic table with little or no bulky-substituent protection at the antimony centre. This provides fundamental insights into heavy element multiple bonding, in particular the tension between orbital-energy-driven and overlap-driven covalency for the actinides in a relativistic regime.

Three-Component Reaction for the Synthesis of Spiro-Heterocycles from Isatins, Substituted Ureas, and Cyclic Ketones.

We reported an efficient three-component reaction to access new spiro heterocycles through the annulation reactions of isatins, substituted ureas, and cyclic ketones under normal laboratory conditions, which is another example of isatins being used to build spiro compounds by the ring-opening and recyclization processes. The wide range of substrates, simple operation, normal experimental conditions, and high yields make the approach of high practical value.

Preferential meropenem absorption activated by 1α,25-dihydroxyvitamin D3 and shared with foscarnet, a phosphate transporter substrate, in the rat ileum

Meropenem (MEPM) is used for the treatment of serious infectious diseases solely as. InjectableTherefore, the development of an oral formulation would expand its clinical utility. To this end, an exact understanding of the absorption characteristics of MEPM is essential. In this study, MEPM absorption in the rat small intestine was investigated using an in situ loop technique and an in vitro diffusion chamber method. The disappearance ratios of MEPM (0.1 mM) were in the order of ileum > duodenum > jejunum. The extensive MEPM disappearance in the ileum was significantly reduced in the presence of foscarnet, a Na+-dependent phosphate transporter (NaPi-T) substrate, whereas glycylsarcosine, thiamine, taurocholic acid, and biapenem had no effects. The mucosal-to-serosal (M-to-S) permeation of MEPM across the rat ileal segments was very small under normal experimental conditions. However, on addition of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) to the experimental medium, the M-to-S permeation of MEPM markedly increased, showing a more than 7-fold greater apparent permeation coefficient. The present results suggest that MEPM is preferentially absorbed in the rat ileum, sharing with foscarnet, and that 1,25(OH)2D3 potentially activates the absorption of MEPM there. A likely candidate for involvement in MEPM absorption was NaPi-T or a related transporter.

Genetic and phenotypic characterizations of IncX3 plasmids harboring bla NDM-5 and bla NDM-16b in Japan.

The spread of the gene encoding the NDM-type carbapenemase, bla NDM, poses a serious threat to clinical practice and public health. This gene is usually carried by transferable plasmids, which facilitates its rapid spread among various species of Enterobacterales. Plasmids with the IncX3 replicon play a major role in the spread of bla NDM in Asian countries. In this study, we conducted genomic sequencing and a comparative analysis of the IncX3-type plasmids harboring bla NDM-5 and bla NDM-16b, a single-nucleotide variant of bla NDM-5, isolated in a national antimicrobial-resistant bacterial genomic surveillance in Japan (Japan Antimicrobial Resistant Bacterial Surveillance), which was carried out during 2019-2020. We compared five plasmids harboring bla NDM-5 and one plasmid harboring bla NDM-16b. They were highly identical and differed in several nucleotide substitutions or variations in insertion sequences, although they were carried by different species or genotypes. Notably, bla NDM-16b-carrying pJBBDACG-19-0070 was identical to a plasmid carrying bla NDM-5 except for one nucleotide substitution in the bla NDM gene throughout the 46 kb sequences. Transformants carrying these two plasmids showed comparative resistance to carbapenems, indicating that a substitution on the NDM enzyme (Ala233 to Val) did not affect carbapenem resistance, at least under normal experimental conditions. A database search revealed that several identical plasmids carrying bla NDM-5 were reported from neighboring countries, mainly China, before our surveillance period. Our analysis suggested that the IncX3 plasmid harboring bla NDM-5 is spreading in Japan, and bla NDM-16b emerged from a single nucleotide substitution on the plasmid, with widespread dissemination in Asian countries. IMPORTANCE IncX3 plasmids harboring bla NDM-5 play a major role in the spread of carbapenem resistance in Asia, particularly in China, in clinical and environmental settings. In this study, we present that Enterobacterales isolates carrying IncX3 plasmids harboring bla NDM-5 have been disseminated in Japan, where their identification was previously rare. In addition, bla NDM-16b, a single-nucleotide variant of bla NDM-5, was found to be carried by an identical IncX3 plasmid. A comparative sequence analysis revealed that the bla NDM-16b gene emerged from a single nucleotide substitution on an IncX3 plasmid harboring bla NDM-5. The bla NDM-16b gene did not confer elevated carbapenem resistance compared to bla NDM-5 in our assay using transformants carrying the plasmid harboring either of these genes, although the A233V substitution was reported to confer stability to the enzyme in ion-depleted conditions. Nevertheless, vigilance regarding the emergence of novel variants is required.

Stabilizing hydrogen-mediated sextuple bonds by quintuple superatomic bonding and a bond.

Multiple bond orders of four and five are frequently obtained for d-block elements. However, compounds with sextuple bonding (2σ, 2π, and 2δ), for instance, Cr2, Mo2 and W2, are less stable and trapped only in the gas phase or inert matrices, probably resulting from large repulsion of two σ-type (σs and ) orbitals within the same zone. Herein, a superatomic bonding model is proposed to describe experimentally synthesized bridging hydride compounds. We theoretically predicted four unprecedented quintuple bridging hydride species with large EHL values, among which [(Cp)2Sc2(μ-H)5]- and [(Cp)2Mn2(μ-H)5]- (Cp = cyclopentadienyl) contain quintuple superatomic bonding (σ, 2π, and 2δ). In particular, two other species, [(Cp)2Ti2(μ-H)5]- and [(Cp)2V2(μ-H)5]+, were found to feature stable hydrogen-mediated sextuple bonding comprising a quintuple superatomic delocalized bond and an extra localized bond. Thereinto, the superatomic σs bond disperses to the outer space for better overlap with the orbitals of bridging H atoms, thus leaving the inner regions with low electron densities and providing adequate space for the bond. These two quintuple bridging hydride compounds are verified to have thermal stability by molecular dynamics simulations and expected to provide an effective strategy to synthesize molecules with stable hydrogen-mediated sextuple bonding under normal experimental conditions.

Open Experimental Data-Sets to Reveal Behavioural Insights of High-Deck Coach Evacuations

Numerous evacuation performance data for the utilization in evacuation modelling and simulations have been established for the conventional/widely studied scenarios, such as building evacuation scenarios. However, such data are typically scarce for a new scenario in literature — evacuation from high-deck coaches. This paper fulfills this gap by presenting empirical high-deck coach evacuation data-sets that can be used for model configuration and validation. To this end, firstly, five essential and commonly used performance metrics, i.e., evacuation time, flow rate, alighting time gap, velocity on stairways and exit choice, were collected and derived from two series of controlled experiments with 7 and 22 runs that involved 44 and 96 participants respectively. Then, all these datasets were structured in the distribution form, based on which three critical behavioural insights are revealed regardless of the evacuation conditions (the types of high-deck coaches, lighting conditions, and age groups). First, the evacuation behaviour in normal (experimental) conditions conforms to a multi-stage pattern (a modified four-stage pattern, i.e., reaction, acceleration, fluctuation and saturation stages). Second, the instantaneous flow rate can be well captured by the Burr, Loglogistic and Lognormal distributions, and the alighting time gap can be represented by the Burr distribution. Third, more than 50% of passengers evacuate through the rear door in the front-and-rear-door evacuations. The frequency of choosing the front door is found to shift towards the direction of the rear door compared to the ideal results (based on the shortest distance calculation) with a magnitude of approximately 1.95 seat rows. The presented data-sets are valuable resources for the development of high-deck coach evacuation models. The empirical findings promote the understanding upon the evacuation behaviour of high-deck coach passengers.

Bonding in a Crystalline Tri‐Thorium Cluster: Not σ‐Aromatic But Still Unique

AbstractVery recently, Boronski et al. reported the first thorium–thorium bond in a crystalline cluster prepared under normal experimental conditions. By using a range of experimental techniques and computational models, the authors found that the isolated actinide cluster contains at its heart two paired electrons delocalized over the tri‐thorium ring. The recorded Raman spectrum allegedly confirmed the existence of a σ‐aromatic three‐center two‐electron bond. In the following we demonstrate that the experimentally observed broad inelastic scattering bands between 60 and 135 cm−1, originally assigned by the authors to thorium‐thorium vibrations, represent the combination of Th−Cl stretching and Th−Cl−Th bending modes, and they establish the existence of an unprecedented multicenter charge‐shift bonding (ThCl2)3 rather than the σ‐aromatic bonding Th3. In the light of the presented findings, the latter remains experimentally unproven and computationally questionable.

Bonding in a Crystalline Tri-Thorium Cluster: Not σ-Aromatic But Still Unique.

Very recently, Boronski et al. reported the first thorium–thorium bond in a crystalline cluster prepared under normal experimental conditions. By using a range of experimental techniques and computational models, the authors found that the isolated actinide cluster contains at its heart two paired electrons delocalized over the tri‐thorium ring. The recorded Raman spectrum allegedly confirmed the existence of a σ‐aromatic three‐center two‐electron bond. In the following we demonstrate that the experimentally observed broad inelastic scattering bands between 60 and 135 cm−1, originally assigned by the authors to thorium‐thorium vibrations, represent the combination of Th−Cl stretching and Th−Cl−Th bending modes, and they establish the existence of an unprecedented multicenter charge‐shift bonding (ThCl2)3 rather than the σ‐aromatic bonding Th3. In the light of the presented findings, the latter remains experimentally unproven and computationally questionable.

A crystalline tri-thorium cluster with σ-aromatic metal-metal bonding.

Metal-metal bonding is a widely studied area of chemistry1-3, and has become a mature field spanning numerous d transition metal and main group complexes4-7. By contrast, actinide-actinide bonding, which is predicted to be weak8, is currently restricted to spectroscopically detected gas-phase U2 and Th2 (refs. 9,10), U2H2 and U2H4 in frozen matrices at 6-7K (refs. 11,12), or fullerene-encapsulated U2 (ref. 13). Furthermore, attempts to prepare thorium-thorium bonds in frozen matrices have produced only ThHn (n = 1-4)14. Thus, there are no isolable actinide-actinide bonds under normal conditions. Computational investigations have explored the probable nature of actinide-actinide bonding15, concentrating on localized σ-, π-, and δ-bonding models paralleling dtransition metal analogues, but predictions in relativistic regimes are challenging and have remained experimentally unverified. Here, we report thorium-thorium bonding in a crystalline cluster, prepared and isolated under normal experimental conditions. The cluster exhibits a diamagnetic, closed-shell singlet groundstate with a valence-delocalized three-centre-two-electron σ-aromatic bond16,17 that is counter to the focus of previous theoretical predictions. The experimental discovery of actinide σ-aromatic bonding adds to main group and dtransition metal analogues, extending delocalized σ-aromatic bonding to the heaviest elements in the periodic table and to principal quantum number six, and constitutes a new approach to elaborate actinide-actinide bonding.

Simulation of Calcium Phosphate Prenucleation Clusters in Aqueous Solution: Association beyond Ion Pairing.

Classical molecular dynamics simulations and free energy methods have been used to obtain a better understanding of the molecular processes occurring prior to the first nucleation event for calcium phosphate biominerals. The association constants for the formation of negatively charged complexes containing calcium and phosphate ions in aqueous solution have been computed, and these results suggest that the previously proposed calcium phosphate building unit, [Ca(HPO4)3]4–, should only be present in small amounts under normal experimental conditions. However, the presence of an activation barrier for the removal of an HPO42– ion from this complex indicates that this species could be kinetically trapped. Aggregation pathways involving CaHPO4, [Ca(HPO4)2]2–, and [Ca(HPO4)3]4– complexes have been explored with the finding that dimerization is favorable up to a Ca/HPO4 ratio of 1:2.

Biochemical aspects of KB-28 compound on physically loaded study subjects

Abstract In previous studies of actoprotective activity of 5-R-thio-tetrazolo[1,5]quinazoline derivatives in normal and complicated experimental conditions, sodium 2-(tetrazolo [1,5-c]quinazoline-5-ylthio)acetate (KB-28) was found to be the leader of the experiment. The objective of the current study was to characterize the effects of KB-28 compounds on carbohydrate and lipid exchange indices under the conditions of physical load as a possible mechanism of actoprotective effect. In the course of the experiment, the indices of carbohydrate and lipid exchange in the muscle, blood and liver of animal models were determined following a 15-day physical load course. In doing so, glucose, glycogen and total lipid concentrations were assessed. The KB-28 compound was administered daily at levels determined during the course of regular physical load normalized metabolic processes in rats. The results were then compared to a control which received intraperitoneally the equivolume 0.9% sodium chloride solution. The phenomenon of actoprotection consisted in enhancing concentrations of glycogen in skeletal muscles and liver. Compared to the control figures, this increase was 28.8% and 25.0%, accordingly. Moreover, the course of KB-28 caused a statistically significant reduction (by 32.1%) of the total serum lipid concentration in the animals under physical load. The effect may be a sign of the ability of this substance to utilize active lipolysis for improvement of the skeletal muscle performance. Having analyzed the results obtained, we can draw a conclusion that influencing the biochemical processes in the study models is one of the mechanisms of the KB-28 actoprotective effect.

Possibility of reducing the coordinated dinitrogen into ammonia and hydrazine using [Ru-L] (L = triamidoamine) and FLP-H $$_{2}$$ 2 : A DFT study

DFT studies have been executed on a hypothetical Ru-triamidoamine complex to understand the possibility of synthesizing ammonia and hydrazine from the dinitrogen at normal temperature and pressure in heptane. In this present study, we utilized the $$\hbox {H}_{2}$$ in the form of FLP- $$\hbox {H}_{2}$$ complex and reacted with Ru-triamidoamine complex. We have added three $$\hbox {H}^{+}$$ and $$\hbox {H}^{-}$$ parts of FLP- $$\hbox {H}_{2}$$ to the Ru complex in a stepwise manner as an alternate way to yield $$\hbox {NH}_{3}$$ / $$\hbox {N}_{2}\hbox {H}_{4}$$ . The catalytic cycle for the formation of $$\hbox {NH}_{3}$$ and $$\hbox {N}_{2}\hbox {H}_{4}$$ were found to be energetically feasible. We have also observed some thermodynamically feasible six coordinate [M]-H intermediates. DFT studies were carried out on the possibility of synthesis of ammmonia and hydrazine from the dinitrogen using Ru-triamidoamine complex via FLP- $$\hbox {H}_{2}$$ under normal experimental conditions. The calculated free energies revealed that the formation of all the intermediates and the transition states are thermodynamically viable. Furthermore, our calculations predicted that the formation of ammmonia is more feasible than hydrazine.

Polyaniline/MWCNTs/starch modified carbon paste electrode for non-enzymatic detection of cholesterol: application to real sample (cow milk).

Nanocomposite materials are potentially revolutionizing many technologies, including sensors. In this paper, we described the application of "PANI/MWCNTs/Starch" modified carbon paste electrode (PCS-CPE) as a simple and highly sensitive cholesterol sensor. This novel nano-composite material has integrated nano-morphology, where polyaniline could interact effectively with the additives; pi-pi stacking "MWCNTs," and covalently bonded with starch. Specific binding sites (sugar chains), better electro-catalytic properties and fast electron transfer facilitated the oxidation of cholesterol. Fourier transform infrared spectra confirmed the interaction of cholesterol with the composite material. The sensing response of PCS was measured by cyclic voltammetry and chronoamperometry (0.1M PBS-5 used as supporting electrolyte). As the amount of cholesterol increased in the test solution, cyclic voltammograms showed a rise of peak current (cathodic and anodic). Under the normal experimental conditions, the developed sensor exhibited wide linear dynamic range (0.032 to 5mM) (upper limit is due to lack of solubility of cholesterol), high sensitivity (800 μAmM-1cm-2), low detection limit (0.01mM) and shorter response time (within 4-6s). Analytical specificity, selectivity, and sensitivity during cholesterol estimation were compared with the response of some other analytes (ascorbic acid, glucose, l-dopa, urea and lactic acid). This novel sensor was successfully applied to estimate cholesterol in cow milk (used as a model real sample). The sensing platform is highly sensitive and shows a linear response towards cholesterol without using any additionalredox mediator or enzyme, thus this material is extremely promising for the realization of a low-cost integrated cholesterol sensor device. Graphical abstract Cyclic voltammetric response of cholesterol of composite modified carbon paste capillary electrode.

The synergistic effect of medial and lateral patellar retinaculum on the stability of patella in full extension

Background: Patellar instability is a common problem. It is unclear that the medial and lateral patellar retinaculum respective effect on patella. The purpose of this study was to evaluate the synergistic effect of medial and lateral patellar retinaculum on the stability of patella. Methods: Eight cadaveric knees were collected. Each of them was performed on patellofemoral joints under five conditions, including normal condition (Group N) and experimental conditions (Group M1, L1, L2, and M2). In Group M1, 2 kg was forced on the normal medial patellofemoral joint using a homemade knee joint immobilization apparatus. In Group L1, 2 kg was forced on the normal lateral patellofemoral joint. In Group L2, the medial retinaculum and the capsule were separated, and the lateral patellar border endured a force of 2 kg. In Group M2, the dissected medial soft tissues were sutured in-situ, and then the lateral retinaculum and the capsule were separated, and the medial patellar border endured a force of 2 kg. Evaluations included CT scan, and the scanned images of these five groups were analyzed for patellar tilt angle (PTA) and the lateral patellar displacement (LPD) values. Results: PTA (°) and LPD (mm) of Group M1 and Group L1 were not significantly different compared to Group N (P≥0.01). PTA values and LPD values of Group L2 and Group M2 increased significantly compared to Group N (P≤0.01). PTA and LPD values of Group L2 showed significant differences compared to Group M2 (P≤0.01). Conclusions: Medial patellar retinaculum prevents LPD and lateral patellar tilt. Lateral patellar retinaculum plays an important role to prevent medial patellar tilt. Medial and lateral retinaculum show synergistic effect to stabilize the patella.

Benzenoid Quinodimethanes.

Reactivity and physical properties of π-conjugated hydrocarbon systems depend predominantly on the topology of π-electrons array. Quinoidal conjugations serve as giving diradical character to molecules, leading to unique chemical behaviors. The simplest member of quinodimethanes are o-, m-, and p-quinodimethanes, which are very reactive due to diradical character and cannot be isolated under normal experimental conditions. However, chemical modifications, such as π-extension or introduction of substituent groups, of quinodimethanes imparts stabilities to quinodimethanes that can be handled under ambient conditions. This chapter offers an overview of reactivity and magnetic properties of benzenoid o-, m-, and p-quinodimethanes.

Protonation of Coordinated Dinitrogen Using Protons Generated from Molecular Hydrogen

A new strategy has been developed to synthesize N–H bonds from coordinated N2 in trans‐[W(dppe)2(N2)2] (1) using protons generated from H2 in the presence of (C6F5)3B and 2,2,6,6‐tetramethylpiperidine, under normal experimental conditions or upon sonication. The complexes [(dppe)2WH(NNH2)][HB(C6F5)3] (2) and [FW(dppe)2(NNH2)][HB(C6F5)3] (3) have been successfully isolated and characterized using standard analytical and spectroscopic methods. We have also monitored the progress of the reaction of complex 1 with a frustrated Lewis pair dihydrogen adduct (FLP‐H2) using standard spectroscopic techniques by following the signatures of the reactants and the products. The results of the current studies are promising for fixing N2 into ammonia by using H2, under normal experimental conditions, in the near future.

Evaluation and improvement of the regulatory inference for large co-expression networks with limited sample size

BackgroundCo-expression has been widely used to identify novel regulatory relationships using high throughput measurements, such as microarray and RNA-seq data. Evaluation studies on co-expression network analysis methods mostly focus on networks of small or medium size of up to a few hundred nodes. For large networks, simulated expression data usually consist of hundreds or thousands of profiles with different perturbations or knock-outs, which is uncommon in real experiments due to their cost and the amount of work required. Thus, the performances of co-expression network analysis methods on large co-expression networks consisting of a few thousand nodes, with only a small number of profiles with a single perturbation, which more accurately reflect normal experimental conditions, are generally uncharacterized and unknown.MethodsWe proposed a novel network inference methods based on Relevance Low order Partial Correlation (RLowPC). RLowPC method uses a two-step approach to select on the high-confidence edges first by reducing the search space by only picking the top ranked genes from an intial partial correlation analysis and, then computes the partial correlations in the confined search space by only removing the linear dependencies from the shared neighbours, largely ignoring the genes showing lower association.ResultsWe selected six co-expression-based methods with good performance in evaluation studies from the literature: Partial correlation, PCIT, ARACNE, MRNET, MRNETB and CLR. The evaluation of these methods was carried out on simulated time-series data with various network sizes ranging from 100 to 3000 nodes. Simulation results show low precision and recall for all of the above methods for large networks with a small number of expression profiles. We improved the inference significantly by refinement of the top weighted edges in the pre-inferred partial correlation networks using RLowPC. We found improved performance by partitioning large networks into smaller co-expressed modules when assessing the method performance within these modules.ConclusionsThe evaluation results show that current methods suffer from low precision and recall for large co-expression networks where only a small number of profiles are available. The proposed RLowPC method effectively reduces the indirect edges predicted as regulatory relationships and increases the precision of top ranked predictions. Partitioning large networks into smaller highly co-expressed modules also helps to improve the performance of network inference methods.The RLowPC R package for network construction, refinement and evaluation is available at GitHub: https://github.com/wyguo/RLowPC.

Parameters for Fabricating Nano-Au Colloids through the Electric Spark Discharge Method with Micro-Electrical Discharge Machining

In this study, the Electric Spark Discharge Method (ESDM) was employed with micro-electrical discharge machining (m-EDM) to create an electric arc that melted two electrodes in deionized water (DW) and fabricated nano-Au colloids through pulse discharges with a controlled on–off duration (TON–TOFF) and a total fabrication time of 1 min. A total of six on–off settings were tested under normal experimental conditions and without the addition of any chemical substances. Ultraviolet–visible spectroscopy (UV–Vis), Zetasizer Nano measurements, and scanning electron microscopy–energy dispersive X-ray (SEM–EDX) analyses suggested that the nano-Au colloid fabricated at 10–10 µs (10 µs on, 10 µs off) had higher concentration and suspension stability than products made at other TON–TOFF settings. The surface plasmon resonance (SPR) of the colloid was 549 nm on the first day of fabrication and stabilized at 532 nm on the third day. As the TON–TOFF period increased, the absorbance (i.e., concentration) of all nano-Au colloids decreased. Absorbance was highest at 10–10 µs. The SPR peaks stabilized at 532 nm across all TON–TOFF periods. The Zeta potential at 10–10 µs was −36.6 mV, indicating that no nano-Au agglomeration occurred and that the particles had high suspension stability.

Phosphine ligands stabilized Cu(I) catalysts for carbene insertion into the N–H bond

Phosphine ligands have been successfully used along with Cu(I) for several catalytic reactions, nevertheless these ligands were less explored relatively for carbene involved reactions owing to the formation of carbene-phosphine ylides. In this report we successfully used three different phosphine stabilized Cu(I) complexes (1–3) as catalysts for chemoselective carbene insertion into the N–H bond of different aromatic amines over the formation of olefin (carbene dimerized product). In order to understand the substrate scope, different α-diazo esters have been reacted with large number of amines and all the reactions produced reasonably good yields under normal experimental conditions (38 examples). All the carbene inserted products have been isolated by column chromatography and fully characterized using standard spectroscopic techniques without any ambiguities. Several control reactions have been conducted in order to understand the importance of the type of phosphine ligands used in the catalysts 1–3 and found that without these catalysts we observed less selectivity (more of olefin as the product over N–H inserted product) and low yield. From this present study, it can be noted that the rigid framework phosphine ligands would be the better choice for carbene chemistry. The results obtained from the current studies would inspire chemists to develop more novel Cu(I)-phosphine catalysts for carbene related reactions including asymmetric versions in the near future.