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A series of Cd(II) complexes, [(PPh3)2Cd(SCOf)2] (1), [PPh4]2[Cd(SCOf)2(μ-Br)]2 (2), [(PPh3)2Ag(μ2-SCOf)2Cd(SCOf)] (3), Na2[(PPh3)Cd(MeOH)(SCOf)3]2 (4a) and Na2[(PPh3)Cd(SCOf)3]2.C7H8 (4b) (Where SCOf = furan-2-thiocarboxylate), have been synthesized and characterized by single crystal X-ray analysis and other spectroscopic techniques. Complexes 1 and 2 show distorted tetrahedral and distorted trigonal bipyramidal geometries around Cd(II), respectively. In the case of 3, Cd(II) exhibits a trigonal prismatic structure, whereas, Ag(I) is at the center of a distorted tetrahedron. Complex 4, has a trigonal pyramidal geometry, hitherto unknown for a Cd(II) center. The catalytic activities of complexes for the synthesis of dihydropyrimidinone have been investigated. Out of four complexes, complex 4 is the most efficient catalyst for the one-pot multicomponent Biginelli-type coupling toward the synthesis of dihydropyrimidinone. Excellent yields of the desired products were obtained with very low catalyst loadings (1 mol%). With a few examples, the versatility and scope of the method have also been demonstrated. The catalysts were also tested for their recyclability. [ABSTRACT FROM AUTHOR]

Borrowing hydrogenation (BH) is a powerful methodology, which is widely adopted for the N-alkylation of amines with alcohols using homogeneous molecular catalysts. To explore the chemistry, herein two novel monomeric Ru(II) complexes [(η6-p-cymene)Ru(L1)Cl2] [Ru-1] bearing 4-trifluromethoxyaniline (L1) and [(η6-p-cymene)Ru(L2)Cl] [Ru-2] bearing quinaldic acid (L2) were synthesized and their structural features were revealed by utilizing analytical and spectroscopic methods like FTIR, 1H and 13C NMR, ESI-MS, and elemental analysis. The lattice structures of both [Ru-1] and [Ru-2] were elucidated by Single Crystal XRD (SC-XRD). Also, aniline-based complex [Ru-3] was synthesized according to the literature and used for comparison. The catalytic efficacy of [Ru-(1–3)] was examined for N-alkylation of amines utilizing alcohols as alkylating agents in benign and solvent-free conditions. The catalytic performance was monitored by GC–MS and HPLC analyses. The primary amine-based (L1) complex [Ru-1] showed a very impressive and efficient conversion of 96%, whereas –N, O donor ligand based (L2) complex [Ru-2] and the unsubstituted aniline based [Ru-3] were able to achieve 25% and 90% conversion, respectively in similar reaction conditions. This drastic variation in catalytic performance was observed due to the co-operative effect of –NH2 in [Ru-1] and [Ru-3]. Metal–ligand cooperation (MLC) in both the complexes stabilizes the intermediate transition state and also the electron deficient Ru(II) center in [Ru-1] has very good binding affinity towards the substrate, which leads to superior catalytic conversion with [Ru-1] compared to [Ru-2] and [Ru-3]. [ABSTRACT FROM AUTHOR]

Azobenzene-based unnatural amino acid motifs were synthesized via Pd(II)-catalyzed diastereoselective C(sp3)–H arylation of amino acid carboxamides with iodoacetanilides and Mills azo coupling. [ABSTRACT FROM AUTHOR]

We report the peculiar characteristics of a polydentate Schiff base towards zinc(II) ions in the presence of pseudohalides (thiocyanate and azide) and the charge transport properties of zinc complex mediated devices in the solid state. The designed polydentate chelator, [HL = (Z)-2-methoxy-6-(((2-methoxy phenyl)imino)methyl)phenol)], was synthesized by coupling of o-anisidine and o-vanillin in ethanol under reflux, and the ligand was isolated in a single-crystalline phase in an orthorhombic system with the Pbca space group. Interestingly, the ligand bears unique structural features towards the coordination with zinc ions in the presence of thiocyanate and azide ions leading to mononuclear and dinuclear zinc–Schiff base–pseudohalide complexes (ZnP11NCS and ZnP11N3), respectively. In the ZnP11NCS complex, the Schiff base ligand becomes protonated to a zwitterionic form, which causes their monodentate/bidentate behaviour towards Zn(II) ions. In contrast, the ligand, P11, under identical reaction conditions, behaves as a tridentate chelating ligand towards Zn(II) ions in the ZnP11N3 complex having a symmetric μ1,1-phenoxo-bridge. In both complexes, NCS and N3 ions coordinate with Zn(II) ions in a terminal coordination mode. Crystal engineering approaches and Hirshfeld surface and energy framework analysis of the complexes delineate the dominant contribution of H⋯S and H⋯N hydrogen bonding and C–H⋯π interactions for a structural assortment of the compounds. Further, the complexes have been employed to construct devices to explore the charge transport properties in the dark and a shower of photons. The ZnP11N3 complex exhibits better charge transport properties than ZnP11NCS as evident from high DC conductivity measurement values and relaxation times caused by optical phonon activation under dark and light conditions. This feature might be utilized to explore their template applications in designing electronic devices as per the industry's needs. [ABSTRACT FROM AUTHOR]

Twenty-five (Ia–Iu, IIa–IIb, IIIa, and IVa) diarylidene-N-methyl-4-piperidones (DANMPs) were synthesized and characterized via UV, FT-IR, NMR, and MS while Id was characterized also by single crystal XRD. Twenty-one compounds shortlisted after initial in vitro anti-plasmodial activity successive screenings at 100 μM and 10 μM were evaluated for their IC50s against chloroquine-sensitive Pf3D7, chloroquine-resistant PfINDO, and artemisinin-resistant PfMRA-1240 strains. The four most promising compounds were Ie (IC50s μM 0.35MRA, 1.39INDO, 1.923D7), If (IC50s μM 1.07MRA, 1.36INDO, 3.393D7), Ir (IC50s μM 0.74MRA, 2.45INDO, 1.443D7), and In (IC50s μM 1.27MRA, 1.8INDO, 1.73D7). Resistance indices as low as 0.2 to 0.5 for these potent compounds and <1 for most other compounds suggest their greater potency against drug resistant strains than the drug sensitive strain. The parasiticidal action of Ir was seen within 4 h against the trophozoite stage of the parasite, which is known to express the highest levels of PLP synthase. In silico docking scores of −7.0 to −8.0 kcal mol−1 between potent DANMPs and PfPLP synthase, the direct binding of Ir studied by SPR to recombinantly expressed and purified PfPdx-1 and inhibition of Pdx1 enzymatic activity by Ir suggest this vital enzyme to be a probable target for the DANMPs. The non-hemolytic nature of Ir and conformity of most DANMPs to Lipinski's parameters indicate their potential as new anti-plasmodial leads with PfPLP synthase as one of their targets. [ABSTRACT FROM AUTHOR]

The reactivity of a bicyclic (alkyl)(amino)carbene (BICAAC) towards different boranes has been examined in the present work. The reactions with boranes BX3·SMe2 (X = H, Cl, Br), BF3·OEt2 and BCl3 yield Lewis adducts [BICAAC·BH3] (1), [BICAAC·BHCl2] (2), [BICAAC·BH2Cl] (3), [BICAAC·BF3] (4), [BICAAC·BCl3] (5) and [BICAAC·BBr3] (6) respectively, whereas more hydridic boranes, 9-borabicyclo[3.3.1]nonane (9-BBN) and catecholborane (HBcat), enable the insertion of the carbene carbon into the B–H bond to form [BICAAC(H)-(9-BBN)] (7) and [BICAAC(H)-Bcat] (8). These complexes are the first examples of BICAAC–boron compounds and have been characterized using IR, multinuclear NMR spectroscopy, HRMS spectrometry and single crystal X-ray diffraction. Computational analyses were also performed to gain insight into the mechanism of B–H bond activation and adduct formation. Furthermore, the reactions of the BICAAC with boranes have been compared with the known reactions of CAACs and NHCs. [ABSTRACT FROM AUTHOR]

The first examples of group 13 element containing pyridinophanes have been assembled using heteroatom N–E–N bridges (E = B, Al). The presence of B and Al as acceptor atoms in the bridges and their coordination with pyridine nitrogen has a very strong influence on the conformational rigidity of the pyridinophanes. [ABSTRACT FROM AUTHOR]

Syntheses of multi-functional Aggregation-Induced Emission (AIE) active molecules in a simple manner have been drawing great attention in current luminescence materials research. In this report a simple diamine molecule (N1-tritylethane-1,2-diamine(1)) is reacted with salicylaldehyde using a Schiff-base technique which results in a new AIE active organic molecule [2-((2-(tritylamino)ethylideneamino)methyl)phenol (2)]. Computational calculations support that the nature of the transition is intra-molecular charge transfer/twisted intramolecular charge transfer (ICT/TICT). The mechanism of AIE has been attributed to restricted intramolecular rotation (RIR). Packing diagrams support that the nature of the aggregation is J-aggregation. The compound, 2, exhibits an irreversible mechanoluminescence (ML) property with a drastic colour change from blue to green (λmax, 445 nm → 512 nm) upon grinding. However, it undergoes a reversible transition with the same colour change (blue → green) through applying pressure axially (using a hydraulic press). The reversible transition is observed by lowering the temperature of 2 to that of liquid nitrogen. The causes of such transitions showing variations in the emission colour upon different triggers have been investigated. In addition, 2 has been successfully tested for the sensing of Zn(ii) and shows a rare turn-on luminescence change, the mechanism behind which has been explored. The detection limit for Zn(ii) is determined to be 0.064 ppm. [ABSTRACT FROM AUTHOR]

Four new Ir(iii) complexes with the general formula [IrHCl(C^N)(PPh3)2] containing different conjugated Schiff base ligands (C^N) have been synthesized and characterized by 1H, 13C, and 31P NMR, HRMS, and IR spectra and one of them by single crystal X-ray diffraction. Their photophysical properties in solution and in the solid state have been analyzed and three main practical results have been obtained: (i) a dual fluorescent and phosphorescent emissive complex in solution, (ii) successful acid/base sensing in the solid state and (iii) quantitative CO2 detection. Quantum chemical calculations have been employed to assign the character of the lowest excited states. A plausible explanation for the observed aggregation induced enhanced emission (AIEE) is given, based on the restriction of intramolecular motions due to the effect of intermolecular C–H…π and C–H…Cl type interactions upon aggregation. [ABSTRACT FROM AUTHOR]

Two equivalents of 1-benzyl-3-bromoethylbenzimidazolium bromide couple with Na2Se to produce the first selenoether bridged bis-benzimidazolium salt (LH2)Br2. The nitrate (LH2)(NO3)2 and tetrafluoroborate (LH2)(BF4)2 salts were also synthesized from (LH2)Br2. The reaction of Hg(OAc)2 with (LH2)Br2 gave the first pseudo pincer carbene mercury complex, [Hg(L-κ2C)][HgBr4] (C1). Different complexes of Pd(ii) with selenoether bridged carbene were obtained using (LH2)Br2 and (LH2)(NO3)2. Syntheses of these complexes were dependent on the counter anion and the temperature. Thus, the pincer type ionic complex [PdBr(L-κ3CSeC)]Br (C2) was isolated at 80 °C and the pseudo pincer type neutral complex cis-[PdBr2(L-κ2C)] (C3) was isolated at room temperature from (LH2)Br2 and Pd(OAc)2 in DMSO. The nitrate precursor (LH2)(NO3)2 on palladation with Pd(OAc)2 afforded [Pd(L-κ4CBzCSeC)]NO3 (C4) showing an unprecedented intramolecular metallation at the ortho position of the benzyl wingtip of the benzimidazole moiety. The ligand salts and metal complexes have been characterized using HRMS, heteronuclear NMR and IR spectroscopy. Single crystal X-ray structures of the ligand salts (LH2)Br2 and (LH2)(BF4)2 and complexes C1–C4 have also been elucidated. Complex C2 showed good activity for C–C coupling in the mono-Heck reaction of methyl acrylate and arylbromides. Interestingly, the less common bis-arylation was also observed with deactivated arylbromides as the result of double-Heck coupling. [ABSTRACT FROM AUTHOR]

The studies of weak interactions involving “organic fluorine” have resulted in a number of conflicts in the literature. Although the involvement of a C–F group in influencing the crystal packing has been demonstrated in various compounds, no one has emphasized the consistency of the synthons formed by C–H…F–C hydrogen bonds. Herein, we have attempted to draw a correlation between the formation of a particular synthon and the positions of the fluorine substitutions from the structural analyses of a model system of tetrafluoro substituted N-benzylideneanilines. A few frequently occurring supramolecular synthons involving C–H…F–C hydrogen bonds have been identified in these and related molecules, and have been quantified by ab initio calculations using the MP2 level of theory and the 6-31+G* basis set in the gas phase. The topological properties of these C–H…F–C hydrogen bonds have been calculated using AIM2000. The nature, strength, directionality and synthon reproducibility of the C–H…F–C hydrogen bonds are the key features presented in this article. [ABSTRACT FROM AUTHOR]

Design and syntheses of 'aggregation induced emission (AIE)' active blue-emitting bis-cyclometalated iridium(III) complexes with appended diphosphine ligands [Ir(F2ppy)2(L1/L2)2(Cl)] (F2ppy = 2-(2′,4′-difluoro) phenylpyridine; L1 = 1,2-bis(diphenylphosphino)ethane; L2 = bis(diphenylphosphino)propane) have been realized on a suitable route. The free phosphorous donor atom present on the appended diphosphine is shown to provide selective binding to the mercuric ion (Hg2+). The selective binding ability of the probe molecule towards mercuric ions results in a detectable signal due to complete quenching of their AIE properties. The quenching effect of the probe molecule has been explored and found to be the result of the degradation of the probe iridium(III) complex triggered by the presence of mercuric ions due to an interplay of a soft-soft interaction between the free phosphorous atom of the probe molecule and mercuric ions. These complexes were modelled to obtain deeper understanding of excited state properties and the results were tentatively correlated with the experimental data. [ABSTRACT FROM AUTHOR]

Azobenzene-based unnatural amino acid motifs were synthesized via Pd(II)-catalyzed diastereoselective C(sp 3 )-H arylation of amino acid carboxamides with iodoacetanilides and Mills azo coupling.

The reactivity of a bicyclic (alkyl)(amino)carbene (BICAAC) towards different boranes has been examined in the present work. The reactions with boranes BX3·SMe2 (X = H, Cl, Br), BF3·OEt2 and BCl3 yield Lewis adducts [BICAAC·BH3] (1), [BICAAC·BHCl2] (2), [BICAAC·BH2Cl] (3), [BICAAC·BF3] (4), [BICAAC·BCl3] (5) and [BICAAC·BBr3] (6) respectively, whereas more hydridic boranes, 9-borabicyclo[3.3.1]nonane (9-BBN) and catecholborane (HBcat), enable the insertion of the carbene carbon into the B-H bond to form [BICAAC(H)-(9-BBN)] (7) and [BICAAC(H)-Bcat] (8). These complexes are the first examples of BICAAC-boron compounds and have been characterized using IR, multinuclear NMR spectroscopy, HRMS spectrometry and single crystal X-ray diffraction. Computational analyses were also performed to gain insight into the mechanism of B-H bond activation and adduct formation. Furthermore, the reactions of the BICAAC with boranes have been compared with the known reactions of CAACs and NHCs.

Design and syntheses of 'aggregation induced emission (AIE)' active blue-emitting bis-cyclometalated iridium(III) complexes with appended diphosphine ligands [Ir(F2ppy)2(L1/L2)2(Cl)] (F2ppy = 2-(2',4'-difluoro) phenylpyridine; L1 = 1,2-bis(diphenylphosphino)ethane; L2 = bis(diphenylphosphino)propane) have been realized on a suitable route. The free phosphorous donor atom present on the appended diphosphine is shown to provide selective binding to the mercuric ion (Hg(2+)). The selective binding ability of the probe molecule towards mercuric ions results in a detectable signal due to complete quenching of their AIE properties. The quenching effect of the probe molecule has been explored and found to be the result of the degradation of the probe iridium(III) complex triggered by the presence of mercuric ions due to an interplay of a soft-soft interaction between the free phosphorous atom of the probe molecule and mercuric ions. These complexes were modelled to obtain deeper understanding of excited state properties and the results were tentatively correlated with the experimental data.

Strong solid-state greenish-blue emitting, mono-cyclometalated iridium complexes, [Ir(ppy)(PPh(3))(2)(H)(Cl)], 2a and [Ir(F(2)ppy)(PPh(3))(2)(H)(Cl)], 2b [ppyH = 2-phenylpyridine; F(2)ppyH = 2-(2',4'-difluoro)phenylpyridine], have been synthesized by a convenient route. The 'aggregation induced enhanced phosphorescence (AIEP)' activity exhibited by these complexes has been rationalized.