O-donor Ligands Research Articles

Synthesis and characterization of N, O-donor Schiff base capped ZnS NPs as a sensor for fluorescence selective detection of Fe 3+, Cr 2+ and Cd 2+ ions

We report the simple synthesis of zinc sulfide nanoparticles (ZnSNPs) by a co-precipitation method using Schiff base, (2-[(4-methoxy-phenylimino)-methyl]-4-nitro phenol) as a capping agent. Here, Schiff base is also used as N, O-donor ligand to control the morphology of NPs and fluorescence interactions. The formation of ZnSNPs and their optical, structural, thermal properties and morphologies were studied by means of UV–vis DRS, fluorescence, FTIR, XRD, SEM, TEM, zeta potential and TGA. The optical properties and quantum confinement effect of the products were confirmed by means of spectroscopic measurements. XRD and TEM image shows that the synthesized ZnSNPs have cubic structures with a diameter of about less than 10 nm. The prepared ZnSNPs exhibited as a selective probe detection of Fe3+, Cr2+ and Cd2+ ions by fluorometrically and the emission band which disappears in the presence of increasing concentrations of Fe3+, Cr2+ and Cd2+ ions. Based on the fluorescence quenching of the NPs in the presence of metal ion of interest, the feasibility of their determinations was examined according to the Stern-Volmer equation. Our work suggested that Schiff base capped ZnSNPs could be a potential selective sensor in the detection of heavy metal ions.

The Largest Supertetrahedral Oxychalcogenide Nanocluster and Its Unique Assembly.

Supertetrahedral oxychalcogenide T n nanoclusters (NCs, n denotes the number of metal-chalcogen layers) integrate chemically distinct but ordered oxygen and chalcogen sites in zinc-blend-type "quantum dots". They therefore offer a new level of control over various properties of semiconducting materials. So far, few such structures are known, and the cluster size is also limited to only T4 with 20 metal sites. Herein, we report an unusual oxysulfide T5 nanocluster with 35 metal sites. It has unprecedented In-O@In-S "core-shell" nanostructure and is also the largest supertetrahedral oxychalcogenide NC. Through cocrystallization, we further demonstrate that such oxychalcogenide NCs can be assembled to form multidimensional structures. In addition to N-donor imidazolates that help to form a 3-D structure with chiral quartz net, the O-donor benzenetricarboxylate (BTC) has also been found to successfully organize such T5 NCs. It is worth noting that no carboxylate ligands have been shown earlier for assembling chalcogenide clusters, despite their prevalence in MOFs. Given the wide availability of O-donor ligands, this work introduces a versatile platform with promise for a new generation of semiconducting inorganic-organic hybrid materials.

The roles of two O-donor ligands in the Fe2+-binding and H2O2-sensing by the Fe2+-dependent H2O2 sensor PerR

PerR is a metal-dependent peroxide sensing transcription factor which controls the expression of genes involved in peroxide resistance. The function of Bacillus subtilis PerR is mainly dictated by the regulatory metal ion (Fe2+ or Mn2+) coordinated by three N-donor ligands (His37, His91, and His93) and two O-donor ligands (Asp85 and Asp104). While H2O2 sensing by PerR is mediated by Fe2+-dependent oxidation of N-donor ligand (either His37 or His91), one of the O-donor ligands (Asp104), but not Asp85, has been proposed as the key residue that regulates the sensitivity of PerR to H2O2. Here we systematically investigated the relative roles of two O-donor ligands of PerR in metal-binding affinity and H2O2 sensitivity in vivo and in vitro. Consistent with the previous report, in vitro the D104E-PerR could not sense low levels of H2O2 in the presence of excess Fe2+ sufficient for the formation of the Fe2+-bound D104E-PerR. However, the expression of PerR-regulated reporter fusion was not repressed by D104E-PerR in the presence of Fe2+, suggesting that Fe2+ is not an effective corepressor for this mutant protein in vivo. Furthermore, in vitro metal titration assays indicate that D104E-PerR has a significantly reduced affinity for Fe2+, but not for Mn2+, when compared to wild type PerR. These data indicate that the type of O-donor ligand (Asp vs. Glu) at position 104 is an important determinant in providing high Fe2+-binding affinity required for the sensing of the physiologically relevant Fe2+-levels, in addition to its role in rendering PerR highly sensitive to physiological levels of H2O2. In comparison, the D85E-PerR did not show a perturbed change in Fe2+-binding affinity, however, it displayed a slightly decreased sensitivity to H2O2 both in vivo and in vitro, suggesting that the type of O-donor ligand (Asp vs. Glu) at position 85 may be important for the fine-tuning of H2O2 sensitivity.

Half-Sandwich Ru(II) and Os(II) Bathophenanthroline Complexes Containing a Releasable Dichloroacetato Ligand.

We report on the preparation and thorough characterization of cytotoxic half-sandwich complexes [Ru(η6-pcym)(bphen)(dca)]PF6 (Ru-dca) and [Os(η6-pcym)(bphen)(dca)]PF6 (Os-dca) containing dichloroacetate(1–) (dca) as the releasable O-donor ligand bearing its own cytotoxicity; pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), bphen = 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline). Complexes Ru-dca and Os-dca hydrolyzed in the water-containing media, which led to the dca ligand release (supported by 1H NMR and electrospray ionization mass spectra). Mass spectrometry studies revealed that complexes Ru-dca and Os-dca do not interact covalently with the model proteins cytochrome c and lysozyme. Both complexes exhibited slightly higher in vitro cytotoxicity (IC50 = 3.5 μM for Ru-dca, and 2.6 μM for Os-dca) against the A2780 human ovarian carcinoma cells than cisplatin (IC50 = 5.9 μM), while their toxicity on the healthy human hepatocytes was found to be IC50 = 19.1 μM for Ru-dca and IC50 = 19.7 μM for Os-dca. Despite comparable cytotoxicity of complexes Ru-dca and Os-dca, both the complexes modified the cell cycle, mitochondrial membrane potential, and mitochondrial cytochrome c release by a different way, as revealed by flow cytometry experiments. The obtained results point out the different mechanisms of action between the complexes.

Separation of the Minor Actinides Americium(III) and Curium(III) by Hydrophobic and Hydrophilic BTPhen ligands: Exploiting Differences in their Rates of Extraction and Effective Separations at Equilibrium

ABSTRACTThe complexation and extraction of the adjacent minor actinides Am(III) and Cm(III) by both hydrophobic and hydrophilic pre-organized 2,9-bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen) ligands has been studied in detail. It has been shown that Am(III) is extracted more rapidly than Cm(III) by the hydrophobic CyMe4–BTPhen ligand into different organic diluents under nonequilibrium extraction conditions, leading to separation factors for Am over Cm (SFAm/Cm) as high as 7.9. Furthermore, the selectivity for Am(III) over Cm(III) can be tuned through careful choice of the extraction conditions (organic diluent, contact time, mixing speed, ligand concentration). This “kinetic” effect is attributed to the higher presumed kinetic lability of the Am(III) aqua complex toward ligand substitution. A dependence of the Am(III)/Cm(III) selectivity on the structure of the alkyl groups attached to the triazine rings is also observed, and BTPhens bearing linear alkyl groups are less able to discriminate between Am(III) and Cm(III) than CyMe4–BTPhen. Under equilibrium extraction conditions, hydrophilic tetrasulfonated BTPhen ligands complex selectively Am(III) over Cm(III) and prevent the extraction of Am(III) from nitric acid by the hydrophobic O-donor ligand N,N,N′,N′-tetraoctyldiglycolamide, giving separation factors for Cm(III) over Am(III) (SFCm/Am) of up to 4.6. These results further underline the utility of the BTPhen ligands for the challenging separation of the chemically similar minor actinides Am(III) and Cm(III).

Cobalt(ii) liquid metal salts for high current density electrodeposition of cobalt.

Cobalt(ii)-containing ionic liquids were synthesized using N,N-dimethylformamide, N-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMAc), pyridine-N-oxide (py-O), 1,10-phenanthroline (phen), ethylenediamine (en) and dimethylimidazolidinone (DMI) as ligands. The weakly coordinating bis(trifluoromethylsulfonyl)imide (Tf2N-) was used as a counter anion. Several compounds had a melting temperature below 100 °C, and the compound [Co(DMAc)6][Tf2N]2 was liquid at room temperature, with a viscosity of only 18 mPa s at 80 °C. Several compounds were recrystallized to give high quality single crystals and their crystal structures were determined. EXAFS measurements were performed on [Co(DMAc)6][Tf2N]2 at different temperatures and it was observed that the [Co(DMAc)6]2+ ion partially dissociated at higher temperatures, which explains the temperature-dependent color change (thermochromism). The electrochemical properties of the compounds with the lowest melting points were also investigated. Adherent, crack-free metallic cobalt layers could be electrodeposited from [Co(DMAc)6][Tf2N]2, [Co(DMI)6][Tf2N]2 and [Co(NMP)6][Tf2N]2. From the first two, black deposits consisting of micrometer-sized needles were obtained, whereas the latter resulted in a dull grey cobalt layer consisting of micrometer-sized cobalt spheres. The Co(iii)/Co(ii) redox couple was not found to occur in any compound with an O-donor ligand, but the Co(iii)/Co(ii) redox couple was found to be quasi-reversible for [Co(phen)3][Tf2N]2 dissolved in [BMP][Tf2N].

Correction to: Biological Evaluation of Copper Complexes Derived from O- and N-, O-Donor Ligands

The title should read: BIOLOGICAL EVALUATION OF COPPER COMPLEXES DERIVED FROM O- AND N-, O-DONOR LIGANDS

A DFT study of the interaction between [Cd(H2O)3]2+ and monodentate O-, N-, and S-donor ligands: bond interaction analysis.

A series of B3LYP/6-311+G(d,p) calculations of the affinity of monodentate ligands for [Cd(H2O)3]2+ are performed. Three types of ligands containing O (phosphine oxide, lactam, amide, carboxylic acid, ester, ketone, aldehyde, ether, halohydrin, enol, furan), N (thiocyanate, amine, ammonia, azide), and S (thioester, thioketone, thiol, thiophene, disulfide) interacting atoms are investigated. The results show that phosphine oxide has the largest affinity for the cadmium cation due to the polarization of the P=O bond. As the P atom has a large atomic radius, the O atom can polarize the electronic cloud enhancing its amount of electronic charge and favoring the interaction with Cd2+. The affinity order found is phosphine oxide > thioester > lactam > amide > carboxylic acid > ester > thioketone > ketone > thiocyanate > amine > ammonia > aldehyde > ether > thiol > thiophene > enol > halohydrin > disulfide > azide > furan ligands. These results were also corroborated by the functional M06-2X. The electronic effects (resonance and induction) of neighboring groups of the interacting atom modulate the strength of metal-ligand binding. For almost all the O-donor ligands the electrostatic component has the same magnitude as the covalent term, while for the N- and S-donor ligands the covalent term is predominant. The polarization term accounts for twice the exchange term as part of the covalent component. The dispersion term varies less than 2kcal mol-1 for the complexes analyzed. The Pauli repulsion term is correlated with the metal ligand distance, increasing in the compounds with decreased metal-ligand bond length. The charge between the interacting atoms is also strongly correlated with both the interacting strength and the electrostatic interaction component. The natural bond orbital analysis highlights correlations of the bond order, and S and P contributions of the interacting metal-ligand orbital with the coordination strength. Graphical abstract The affinity of 20 monodentate ligands with different functional groups for the [Cd(H2O)3]2+ cation is calculated based on the interaction enthalpy and Gibbs free energy for the substitution of one water molecule from the fully hydrated cation. The affinity is correlated with geometric, electronic, and energetic parameters of the ligands and the complexes as well as with energy decomposition and natural bond order analyses results.

Coordination chemistry: niobium(V) and tantalum(V) with O-donor ligands

Coordination chemistry: niobium(V) and tantalum(V) with O-donor ligands

Complexes of molybdenum(VI) oxide tetrafluoride and molybdenum(VI) dioxide difluoride with neutral N- and O-donor ligands

[MoOF4(MeCN)], prepared from reaction of MoF6 with (Me3Si)2O in anhydrous MeCN solution, reacts with the neutral O-donor ligands, thf, Ph3PO, Me3PO, dmf and dmso, (L) in a 1:1 molar ratio under rigorously anhydrous conditions to form six-coordinate [MoOF4(L)], which have been characterised by microanalysis, IR, 1H, 19F{1H} and 95Mo NMR spectroscopy. In the presence of moisture the major products are [MoO2F2(L)2], which can be made directly by reaction of [MoOF4(L)] with a further equivalent of L and (Me3Si)2O. [MoOF4(MeCN)] and 2,2′-bipyridyl produce the insoluble [MoOF4(bipy)], which is probably 7-coordinate. Ph3AsO is quantitatively converted to Ph3AsF2 by [MoOF4(MeCN)], and soft ligands, including Me2S, Me3P and Me3As, reduce the oxide fluoride on contact. Unstable [MoO2F2(MeCN)2] has also been prepared and the X-ray structure of [MoO2F2(MeCN)2]·MeCN is reported. X-ray crystal structures are reported for [MoOF4(Ph3PO)], [MoO2F2(Ph3PO)2], [MoO2F2(Me3PO)(H2O)] and [Mo2O4F2(μ-F)2(Me3PO)2]. Comparisons with the corresponding chemistries of WOF4 and WO2F2 are described.

Structural and topological regulation on cobalt coordination polymers with mixed ligands

Structural and topological regulation on a series of cobalt coordination polymers (CPs) built by V-shaped O-donor ligand, 4,4′-(hexafluoroisopropylidene)-bis(benzoic acid) (H2L), and auxiliary N-donor ligands was reported. The introduction of secondary N-donor ligands (2,2′-bipyridine, BPY; 1,3-bis(4-pyridyl)propane, BPP) greatly affected the overall structures of cobalt CPs, due to the structural taloring/directing effect of the neutral coordinating molecules BPY and BPP. The CPs were characterized by single crystal X-ray diffractions, infrared spectroscopy, thermogravimetry measurements, elemental analyses and X-ray powder diffractions. X-ray crystallography suggested the CPs possess 2-D covalent network structures, which identified versatile underlying topological structures. Moreover, magnetic properties of two complexes were also explored.

Developments in transfer hydrogenations of aromatic ketones catalyzed by boron compounds

Boron complexes BL1 and BL2 were prepared from O-donor ligands, 2,2′-(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(methane-1-yl-1-ylidene)diphenol (L1) and 2,2′-(propane-1,3-diylbis(azan-1-yl-1-ylidene))bis(methane-1-yl-1-ylidene)diphenol (L2). The complexes were fully characterized by 1H and 13C NMR, LC-MS/MS, TGA/DTA, UV-Vis, elemental analysis, SEM, and FTIR. The transfer hydrogenation of acetophenone derivatives was investigated by the boron complexes in the presence of isoPrOH, as the hydrogen source, under basic condition with NaOH. The results showed that the boron complexes were promising catalytic precursors for transfer hydrogenation of aromatic ketones in 0.1 M isoPrOH solution (up to 99%). Both steric and electronic factors of this class of molecules had a significant impact on the catalytic properties.

High yielding electrophilic amination method for arylcopper reagents

ABSTRACTThe facilitative effect of some P-, N-, S-, and O-donor ligands in the reaction of arylcoppers with acetone O-(mesitylenesulfonyl)oxime was examined to develop a synthesis method for functionalized primary aryl amines under mild reaction conditions. Our research showed that electrophilic amination of monoaryl coppers with ketoximes can be facilitated using appropriate ligand to supply significant increase in the yield. Also, we have seen that this ligand-facilitated method is applicable in terms of arylcopper and ketoxime type and allows synthesis of primary aryl amines in good to high yields easily at room temperature in very short reaction time.

Anticancer activity and tissue distribution of platinum (II) complex with lignin-derived polymer of benzene-poly-carboxylic acids

Platinum-containing antineoplastic agents with physiologically active ligands seem to be a promising direction in anticancer drug design. PDBA is a novel promising antineoplastic agent, containing polymer ligand of natural origin (international patent WO2013/143549 A1). Polymer ligand of PDBA has a highly functionalised polyphenolic backbone, which exerts its own pharmacological effect via immune modulation and regulation of gene expression. PDBA is a cis-diammineplatinum(II) complex, containing mono-deprotonated benzene-poly-carboxylic acids, derived from lignin, and hydroxyl group as O-donor ligands (approximate bulk formula C83H70N2O27Pt). The agent is being evaluated in Phase II controlled clinical trials in metastatic breast cancer patients. In the present study, tissue distribution and tumour growth inhibition effects of PDBA, cisplatin and carboplatin were compared in SHR female mice, bearing inoculated solid Ehrlich carcinoma. The agents were administered subcutaneously every second day for the period of 10days (5 injections) at 62.5mg/kg, 3.0mg/kg and 18.5mg/kg for PDBA, cisplatin and carboplatin, respectively. Experimental animals were sacrificed on the Days 11, 16 and 23 after the inoculation of the tumour. The doses of all studied drugs were selected to obtain similar antitumour efficacy with ca. 50% growth inhibition of the Ehrlich tumour at the end of the study. The efficacy of a single platinum reactive moiety [cis-diammineplatinum(II)] was shown to be the highest for cisplatin, followed by PDBA and finally carboplatin. However, the toxicity of PDBA was considerably lower than that of carboplatin and especially cisplatin. The drugs were mainly distributed in lungs, kidneys, liver, spleen and tumour tissue. PDBA showed quite high accumulation in the tumour tissue, possibly, owing to the effect of the lignin-derived ligand.

Complexes of vanadium(IV) oxide difluoride with neutral N- and O-donor ligands

A convenient new synthesis for complexes of VOF2 with N-donor ligands is via the reaction of VF4 with the ligand in water, either under reflux or using hydrothermal conditions. The complexes, mer-[VOF2(terpy)]·3H2O (terpy=2,2′6′,2‴-terpyridyl), [VOF2(bipy)(H2O)], [VOF2(phen)(H2O)], [VOF2(py)2(H2O)], [VOF2(py)2(H2O)]·H2O, [V2O2F4(py)4] and [pyH]2[V2O2F6(H2O)2], along with the O-donor, pyridine N-oxide (pyNO) complex, [V2O2F4(H2O)2(pyNO)2], have been isolated and characterised. The controlled hydrolysis of VF4 in water produces the hydrate [VOF2(H2O)2]·H2O. The complex [VOF2(Me3tacn)] (Me3tacn=1,4,7-trimethyl-1,4,7-triazacyclononane) was prepared by the reaction of [VOF2(py)2(H2O)] and Me3tacn in MeCN. The new complexes have been characterised by microanalysis and single crystal X-ray diffraction. Powder X-ray diffraction (PXRD) data were recorded for the bulk samples and compared with the PXRD patterns simulated from the single crystal data to confirm that the latter were representative of the bulk products. All the complexes contain six-coordinate vanadium(IV), with extensive H-bonding and (in the pyridyl ligand complexes) π-stacking interactions present. IR and UV–visible spectroscopic data and magnetic measurements are also reported and discussed. Attempts to obtain phosphine oxide or ether complexes by similar routes were unsuccessful. Unless the temperature is carefully controlled, the hydrothermal route yields mixtures of VIV and VV complexes.

Two complexes of copper (II) and cobalt (II) with N,O-chelating heterocyclic carboxylates: Crystal structures, Hirshfeld surfaces, and thermal properties

ABSTRACTTwo complexes 1 [Cu(L1)2(H2O)2]·2H2O and 2 [Co(L2)2 (H2O)4]·4H2O formed by hetero N- and O-donor ligands 1-methyl-3-imidazole-4-carboxylic acid (L1H) and 2-methyl-5-pyridine carboxylic acid (L2H) have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. These two complexes consist of a 2:1 ratio of ligand to metal ion. The analysis of Hirshfeld surfaces and crystal structures reveal that O‒H···O hydrogen bond interactions and C‒H···π intermolecular interactions support the three-dimensional supramolecular structures of complexes 1 and 2. Meanwhile, the coordinated water molecules and lattice water molecules play a key role in the construction of their crystal structures.

Polycarboxylic acids in sea water: acid–base properties, solubilities, activity coefficients, and complex formation constants at different salinities

This paper reports the results of the investigations carried out in synthetic sea water at different salinities for different classes of polycarboxylic acids. The investigations can be summarized as follows: (a) Determination of the protonation constants in such multicomponent solution in a salinity range 15 ≤ S ≤ 45, at t = 25 °C, for the linear dicarboxylic acids HOOC-(CH2) n –COOH (0 ≤ n ≤ 8), and aromatic polycarboxylic acids (o-phthalic and 1,2,4-benzenetricarboxylic acids). For malonic, succinic, 1,2,3-benzenetricarboxylic, and 1,2,3,4-benzenetetracarboxylic acids, investigations were also carried out at t = 10 and 37 °C; (b) Determination of the total and intrinsic solubility (S T and S 0, respectively) of the linear dicarboxylic acids HOOC-(CH2) n -COOH (0 ≤ n ≤ 8), o-phthalic, 1,2,4-benzenetricarboxylic acids at t = 25 °C and 15 ≤ S ≤ 45, and calculation of the corresponding Setschenow parameters and activity coefficients; (c) Modeling the dependence of the experimental and literature protonation constants of the polycarboxylic acids on salinity, acid concentration, temperature, and number of the methylene groups in the molecules by means of new empirical equations; (d) Determination of the specific interaction parameters in synthetic sea water of the ionic species of the acids by means of the specific ion interaction theory and Pitzer models; (e) Determination of the protonation constant of the anion A1.117− of the single salt BA at different salinities and temperatures; (f) Determination and modeling in dependence of the salinity of the ΔH/kJ mol−1 of protonation of the linear dicarboxylic acids and of the A1.117− anion, by means of a Debye-Huckel type equation; (g) Determination of the complex formation constants (log β BpLHi) between the cation B1.117+ and the different deprotonated species of the carboxylic acids at different salinities and temperatures. Independent of the thermodynamic aqueous properties determined, a significant dependence of these parameters (log β i H , log β BpLHi, ΔH/kJ mol−1 of protonation, S T and S 0) on the ionic medium, salinity, and temperature was observed. Moreover, the huge number of data collected allowed us to propose some empirical equations to model/predict the behavior of these classes of O-donor ligands in a multicomponent solution such as synthetic sea water.

Bandgap Engineering of Titanium-Oxo Clusters: Labile Surface Sites Used for Ligand Substitution and Metal Incorporation.

Through the labile coordination sites of a robust phosphonate-stabilized titanium-oxo cluster, 14 O-donor ligands have been successfully introduced without changing the cluster core. The increasing electron-withdrawing effect of the organic species allows the gradual reduction of the bandgaps of the {Ti6 } complexes. Transition-metal ions are then incorporated by the use of bifunctional O/N-donor ligands, organizing these {Ti6 } clusters into polymeric structures. The coordination environments of the applied metal ions show significant influence on their visible-light adsorption. Both the above structural functionalizations also tune the photocatalytic H2 production activities of these clusters. This work provides a systematic bandgap engineering study of titanium-oxo clusters, which is important not only for their future photocatalytic applications, also for the better understanding of the structure-property relationships.

Coordination complexes of the tungsten(VI) oxide fluorides WOF4 and WO2F2 with neutral oxygen- and nitrogen-donor ligands

Abstract [WOF4(MeCN)], prepared from a 1:1 ratio of WF6 and O(SiMe3)2 in MeCN, is a convenient synthon for the preparation of complexes of WOF4 and WO2F2 with neutral N- or O-donor ligands. It reacts with monodentate ligands L (L = OPPh3, OPMe3, dmso, py) in a 1:1 ratio to form [WOF4L], whilst reaction of [WOF4(MeCN)], O(SiMe3)2 and L⿲ (L⿲ = OPPh3, py, pyNO, dmso) in 1:1:2 ratio affords [WO2F2L⿲2]. The synthesis of [WO2F2(L-L)] (L-L = Ph2P(O)CH2P(O)Ph2 or 1,10-phenanthroline) are also described. Similar complexes with arsines, thio- or seleno-ethers are not formed by these routes. The complexes have been characterised by microanalysis, IR, 1H and 19F{1H} NMR spectroscopy, and X-ray crystal structures are reported for [WOF4(OPPh3)], [WO2F2(OPPh3)2], [WO2F2{Ph2P(O)CH2P(O)Ph2}] and [WO2F2(pyNO)2].

Syn-Bimane as a chelating O-donor ligand for palladium(ii).

A cationic Pd(ii) complex containing syn-(Me,Me)bimane as a ligand was prepared and fully characterized. This complex represents the first well-defined case of a bimane scaffold coordinated to a metal center. The strongly-fluorescent syn-bimane chelates the Pd(ii) center via its carbonyl oxygen atoms, affording a non-fluorescent complex. The crystal structure of this complex shows that the coordinated bimane departs from planarity, with its bicyclic framework bent about the N-N bond. Spectroscopic evidence demonstrates that bimane coordination is reversible in solution.