Dppm Ligands Research Articles

Straightforward coordination-driven supramolecular chemistry preparation of a discrete solid-state luminescent Cu4 polymetallic compact assembly based on conformationally flexible building blocks

The ditopic nitrile-capped 1,4-phenylenediacetonitrile linker L3 featuring partial conformational flexibility was reacted with a flexible pre-assembled Cu(I) dimer stabilized by the bis(diphenyl-phosphino)methane dppm ligand along adaptive coordination-driven supramolecular assembling processes. It resulted in the selective and unexpected formation of a compact tetrametallic assembly associating two bimetallic building blocks with three ditopic linkers. The solid-state photophysical studies of this original Cu(I)-based assembly were analysed and showed its attractive luminescence properties.

Thermolysis of [HOs3(CO)8{µ3-Ph2PCH2P(Ph)C6H4}]: New Os2- and Os3- cluster products based on multiple C[sbnd]H bond activation of the bis(diphenylphosphino)methane ligand

Thermolysis of [HOs3(CO)8{µ3-Ph2PCH2P(Ph)C6H4}] in refluxing xylene has been investigated, and three new polynuclear osmium compounds containing an activated dppm ligand(s) as a result of multiple CH bond cleavages have been isolated. The new complexes are [H2Os3(CO)8{µ3-Ph2PCHP(Ph)C6H4}] (1), [H2Os3(CO)6(µ3-Ph2PCHPPh2){µ3-Ph2PCH2P(Ph)C6H4}] (2) and [Os2(CO)6{µ-H4C6(Ph)PCH2P(Ph)C6H4}] (3), each of which exhibits a different coordination mode involving the activated diphosphine ligand. Cluster 1 is formed by CH bond oxidative addition of the backbone methylene spacer and an ortho site at an ancillary aryl ring. Control experiments confirm that cluster 2 is formed from cluster 1 and dppm. The dinuclear compound 3 is formed via metalation of two phenyl rings on the dppm ligand and is accompanied by the release of an osmium atom. The molecular structure of each new complex has been established by single-crystal X-ray diffraction analysis, and the bonding in compounds 1–3 has been examined by DFT calculations.

Facile entry to germanate and stannate complexes [(η6-arene)RuCl(η2-dppm)]+[ECl3]- (E = Ge, Sn) as potent anti-cancer agents

A series of arene Ru(II) salt complexes of the type [(η6-arene)RuCl(η2-dppm)]+[ECl3]- (arene = C6H6,p-cymene, 1,3,5-Me3C6H3; E = Ge, Sn) bearing trichlorogermanate and trichlorostannate anions are reported. Starting from the known complexes: [(η6-C6H6)RuCl2(η1-dppm)] (1), [(η6-p-cymene)RuCl2(η1-dppm)] (3) and the novel complex [(η6-1,3,5-Me3C6H3)RuCl2(η1-dppm)] (7) (dppm = 1,1-bis(diphenylphosphino)methane), reactions with SnCl2 or GeCl2(dioxane) respectively afforded, by halide abstraction at the ruthenium(II) centres in 1, 3 or 7 the salts: [(η6-C6H6)RuCl(η2-dppm)]+ SnCl3− (2), [(η6-p-cymene)RuCl(η2-dppm)]+ SnCl3− (4), [(η6-C6H6)RuCl(η2-dppm)]+ GeCl3− (5), [(η6-p-cymene)RuCl(η2-dppm)]+ GeCl3− (6), [(η6-1,3,5-Me3C6H3)RuCl(η2-dppm)]+ SnCl3− (8) and [(η6-1,3,5-Me3C6H3)RuCl(η2-dppm)]+ GeCl3− (9). The trichlorostannate complexes 2, 4 and 8 are extremely rare examples of ruthenium complexes bearing the SnCl3− counter anion, and the complexes 5, 6 and 9 are the first examples of ruthenium trichlorogermanate complexes to be reported. All compounds were isolated in high yields as air stable materials and were spectroscopically characterized by multinuclear NMR: (1H, 31P{1H}, 13C{1H}), Infra-red (IR), UV–Vis, and high resolution electrospray ionization mass spectrometry (HR-ESI-MS), the latter both in (+) and (−) mode. Additionally, single crystal X-ray diffraction analyses of salts 4 and 6 are reported, revealing pseudotetrahedral Ru(II) centres with η6 bound p-cymene ligands and η2-bound dppm ligands with statistical disorder on the ECl3- anions (E = Ge (6), Sn (4)). Density functional theory calculations (B3LYP with the basis set 6-31 + G(d,p) for H, C, P and Cl atoms; while for Ru, Ge, and Sn atoms DGDZVP basis set) are reported for salts 4 and 6 revealing localization of the LUMOs on the ruthenium-arene rings and some localization on the chloride atom. Finally, MTT in vitro cytotoxicity assays for the MCF-7 and MDA-MB-231 breast cancer cell lines are reported for all complexes and compared to cisplatin. All complexes show remarkable in vitro cytotoxic activity and most are considerably more cytotoxic than cisplatin in both breast cancer cell lines: IC50 values range from 2.25 μM (compound 2) to 5.97 μM (compound 9) (cisplatin = 5.74 μM) in MCF-7 cells; 2.20 μM (compound 2) to 6.39 μM (compound 5) (cisplatin = 13.98 μM) in MDA-MB-231. Moreover, when compared to non-malignant breast epithelial cells (MCF12A), all complexes exhibit promising selectivity indices (SI) with compound 5 having the highest SI in MCF-7 cells at 4.8; and compound 6 at 3.65 in MDA-MB-231, with most of the other compounds also being considerably more selective than cisplatin on both cell-lines (SI = 2.26 on MCF-7 and 0.93 on MDA-MB-231). A clonogenic assay was conducted for salts 5 and 6 and the results reveal that both compounds inhibited long-term (14 days) survival in both breast cancer cell lines tested indicating these drugs are very promising candidates for pre-clinical studies.

Synthesis, structures, and electrocatalytic properties of phosphine‐monodentate, −chelate, and ‐bridge diiron 2,2‐dimethylpropanedithiolate complexes related to [FeFe]‐hydrogenases

To further extend diiron subsite models of [FeFe]‐hydrogenases, the various substitutions of all‐carbonyl diiron complex Fe2(μ‐Me2pdt)(CO)6 (A, Me2pdt = (SCH2)2CMe2) with monophosphines or small bite‐angle diphosphines are studied as follows. Firstly, the monodentate complexes Fe2(μ‐Me2pdt)(CO)5{κ1‐P(C6H4R‐p)3} [R = Me (1a) and Cl (1b)] and Fe2(μ‐Me2pdt)(CO)5{κ1‐Ph2PX'} [X' = NHPh (2a) and CH2PPh2 (2b)] are readily afforded through the Me3NO‐assisted reactions of A with monophosphines P(C6H4R‐p)3 (R = Me, Cl) and diphosphines (Ph2P)2X (X = NPh, CH2 (dppm)) in MeCN at room temperature, respectively. Secondly, the chelate complexes Fe2(μ‐Me2pdt)(CO)4(κ2‐(Ph2P)2X) [X = NPh (3a) and NBun (3b)] can be efficiently prepared by the UV‐irradiated reactions of A with small bite‐angle diphosphines (Ph2P)2X (X = NPh, NBun) in toluene. Thirdly, the bridge complexes Fe2(μ‐Me2pdt)(CO)4(μ‐(Ph2P)2X) [X = NPh (4a) and CH2 (4b)] are well obtained from the refluxing solutions of A and diphosphines (Ph2P)2X (X = NPh, CH2) in xylene. Rarely, the diphosphine‐bridge complex 4b may be produced in low yield via the UV‐irradiated solutions of A and the dppm ligand in toluene emitting at 365 nm. Eight new complexes obtained above have been well characterized by using element analysis, FT‐IR, NMR (1H, 31P) spectroscopies, and particularly for 1a, 1b, 2a, 3b, 4a, 4b by X‐ray crystallography. Meanwhile, the electrochemical and electrocatalytic properties of three representative complexes 2a, 3a, and 4a with pendant N‐phenyl groups are investigated and compared by using cyclic voltammetry (CV) in the absence and presence of trifluoroacetic acid (TFA) as a proton source, indicating that they are all found to be active for electrocatalytic proton reduction to hydrogen (H2).

Influence of pendant amines in phosphine ligands on the formation, structures, and electrochemical properties of diiron aminophosphine complexes related to [FeFe]-hydrogenases

Me3NO-assisted substitution reactions of precursor Fe2(μ-adtNPh)(CO)6 (A, adtNPh = SCH2N(Ph)CH2S) and aminodiphosphines (Ph2P)2NR with different N-aryl substituents (R) resulted in the unexpected formation of five new diiron aminophosphine complexes Fe2(μ-adtNPh)(CO)5{κ1-Ph2P(NHR)} (R = C6H5 (1), C6H4Me-p (2), C6H4OMe-p (3), C6H4CO2Me-p (4), and C6H4Cl-p (5)) with adtNPh bridge, which may be regarded as the active site models of [FeFe]-hydrogenases. In order to further observe the influence of the pendant amines of phosphine ligands on the formation, structures, and electrochemical properties of model complexes 1–5 obtained above, two reference analogues Fe2(μ-adtNPh)(CO)5(κ1-dppm) (6, dppm = (Ph2P)2CH2) and Fe2(μ-adtNPh)(CO)5{κ1-Ph2P(CH2Ph)} (7) were prepared from the similar treatment of A with the dppm or Ph2P(CH2Ph) ligands, respectively. Meanwhile, these new complexes 1–5 and 7 have been characterized by elemental analysis, FT-IR and NMR (1H, 31P) spectroscopies, and particularly for 1, 2, 4, 7 by X-ray crystallography, in which the P atoms of the Ph2P(NHR) ligands in 1, 2, 4 reside in an apical position whereas that of the Ph2P(CH2Ph) ligand in 7 occupies at a basal site in the solid state. In addition, the electrochemical and electrocatalytic behaviors of 1–5 and 7 are investigated and compared in the absence and presence of acetic acid (HOAc) as proton source using cyclic voltammetry (CV), indicating they are all found to be active eletrocatalysts for proton reduction to hydrogen (H2).

Structure of the ligated Ag60 nanoparticle [{Cl@Ag12}@Ag48(dppm)12] (where dppm=bis(diphenylphosphino)methane)

A novel bisphosphine ligated Ag60 nanocluster, [{Cl@Ag12}@Ag48(dppm)12], has been discovered and characterized by X-ray crystallography. It consists of a central chloride located inside an icosahedral silver core layer, which is further encased by a second shell of 48 silver atoms/ions, which are capped with 12 bis(diphenylphosphino)methane (dppm) ligands. Due to lack of sufficient material the cluster could not be further characterized by other methods. DFT calculations were carried out on the cation [{Cl@Ag12}@Ag48(dppm)12]+ to determine if it corresponds to a superatom with a core count of n=58. The DFT optimized structure is in agreement with X-ray findings, but the low value of the HOMO-LUMO gap does not support superatom stability.

Diphosphine-induced thiolate-bridge scission of [Re(CO)3(μ,κ2-S,N-thpymS)]2 (thpymS = 1,4,5,6-tetrahydropyrimidine-2-thiolate): Structural and computational studies of configurational isomers of [Re(CO)3(κ2-S,N-thpymS)]2(μ,κ1,κ1-dppe)

Reactions of binuclear [Re(CO)3(μ,κ2-S,N-thpymS)]2 (1) with diphosphines have been investigated. At 298 K, dppm reacts to give mononuclear [Re(CO)3(κ1-dppm)(κ2-S,N-thpymS)] (2) through a phosphine-promoted scission of the dithiolate bridges that leaves one of the phosphine moieties free (dangling). Refluxing 2 in toluene leads to CO loss and formation of dinuclear [Re2(CO)4(μ-dppm)(μ,κ2-S,N-thpymS)2] (3) whose rhenium centers are bridged by two thiolate groups and the dppm ligand. Treatment of 1 with dppe at room temperature furnishes [Re(CO)3(κ2-S,N-thpymS)]2(μ,κ1,κ1-dppe) (4) where each phosphine center ligates the respective d6-ML5 rhenium fragment. Complex 4 exists as two distinct configurational isomers (4a and 4b) that have been isolated and the solid-state structures characterized crystallographically. The principal difference in the stereoisomeric products is the orientation of the two [Re(CO)3(κ2-S,N-thpymS)] moieties at the anti-staggered Newman projection involving the P-C-C-P backbone of the dppe ligand. Both stereoisomers retain their identity in solution at ambient temperatures but equilibrate to a 1:1 mixture upon heating at 363 K for 1 h. The reaction of 1 with dppe in toluene at 383 K affords [Re(CO)2(κ1-dppe)2(κ2-S,N-thpymS)] (5) containing two monodentate (dangling) diphosphine ligands. Thus, these seemingly simple reactions afford a range of different products whose composition is highly dependent upon the experimental conditions employed and the nature of the diphosphine backbone. The reaction of 1 with dppe and the process responsible for the equilibration of the two configurational isomers of 4 have been investigated by electronic structure calculations.

Influence of the Diphosphine Coordination Mode on the Structural and Optical Properties of Cyclometalated Platinum(II) Complexes: An Experimental and Theoretical Study on Intramolecular Pt···Pt and π···π Interactions.

The reaction of [Pt(C^N)(CF3CO2)(SMe2)] (1), in which C^N is either benzo[ h]quinolinate (bhq), 1a, or 2-phenylpyridinate (ppy), 1b, with 1 equiv of bis(diphenylphosphino)methane (dppm) gave the bischelate complexes [Pt(C^N)dppm]CF3CO2 (2). The binuclear complexes [Pt2(C^N)2(CF3CO2)2(μ-dppm)] (3) were prepared, using an unusual reaction pathway, by the addition of equimolar amount of complexes 1 and 2, through the ring opening of the chelating dppm ligand and coordination of the CF3CO2 anion to the platinum center. The proposed reaction pathway and effect of the solvent polarity were investigated by density functional theory (DFT) calculations. The crystal structure of 3a shows considerable intramolecular Pt···Pt and π···π interactions. The crystal structure and formation pathway toward 3 were compared with the similar analogue [Pt2(bhq)2(Cl)2(μ-dppm)] (5). All complexes were fully characterized using multinuclear NMR spectroscopy and elemental analysis. Furthermore, the crystal structures of some complexes including 1b, 2a, 2b, 3a, and 5 were confirmed by X-ray crystallography. The effect of dimerization via a change in the coordination mode of dppm, from a chelate mode in complex 2 to a bridge mode in complexes 3 and 5, upon the excited states of the studied compounds was investigated in their distinguished absorption and emission profiles. The appearance of a remarkably low energy band in the absorption spectra of 3, which was assigned to a metal-metal to ligand charge transfer [MMLCT; dσ*(Pt2) → π*(C^N)] transition showing negative solvatochromism, is important evidence for the Pt···Pt intramolecular interaction. The vibronically resolved and long-lifetime emission of 2a in poly(methyl methacrylate) media and powder states at 77 and 300 K, along with time-dependent DFT calculations, suggested that the triplet ligand-centered (3LC) emission was mixed with some 3MLCT character. Unstructured and short-lifetime emission in 3 refers to the phosphorescence 3MMLCT [dσ*(Pt2) → π*(C^N)] transition. Although complex 5 is a binuclear compound, the long distance of the Pt···Pt interaction caused the occurrence of the 3MMLCT transition to fade and act as a mononuclear unit, and the emission originated mostly from the 3MLCT transition. As a result, more metal participation leads to more red-shifted absorption and emission spectra of the studied complexes upon going from LC to MLCT to MMLCT transitions (λabs and λem: 3a > 3b > 5 > 2a > 2b).

Organometallic Nucleosides: Synthesis and Biological Evaluation of Substituted Dicobalt Hexacarbonyl 2'-Deoxy-5-oxopropynyluridines.

Reactions of dicobalt octacarbonyl [Co2(CO)8] with 2′‐deoxy‐5‐oxopropynyluridines and related compounds gave dicobalt hexacarbonyl nucleoside complexes (83–31 %). The synthetic outcomes were confirmed by X‐ray structure determination of dicobalt hexacarbonyl 2′‐deoxy‐5‐(4‐hydroxybut‐1‐yn‐1‐yl)uridine, which exhibits intermolecular hydrogen bonding between a modified base and ribose. The electronic structure of this compound was characterized by the DFT calculations. The growth inhibition of HeLa and K562 cancer cell lines by organometallic nucleosides was examined and compared to that by alkynyl nucleoside precursors. Coordination of the dicobalt carbonyl moiety to the 2′‐deoxy‐5‐alkynyluridines led to a significant increase in the cytotoxic potency. The cobalt compounds displayed antiproliferative activities with median inhibitory values (IC50) in the range of 20 to 80 μm for the HeLa cell line and 18 to 30 μm for the K562 cell line. Coordination of an acetyl‐substituted cobalt nucleoside was expanded by using the 1,1‐bis(diphenylphosphino)methane (dppm) ligand, which exhibited cytotoxicity at comparable levels. The formation of reactive oxygen species in the presence of cobalt compounds was determined in K562 cells. The results indicate that the mechanism of action for most antiproliferative cobalt compounds may be related to the induction of oxidative stress.

Luminescent Three- and Four-Coordinate Dinuclear Copper(I) Complexes Triply Bridged by Bis(diphenylphosphino)methane and Functionalized 3-(2'-Pyridyl)-1,2,4-triazole Ligands.

A new series of bimetallic Cu(I) complexes 1-5 triply bridged by a monoanionic or charge-neutral functionalized 3-(2'-pyridyl)-1,2,4-triazole in a μ-η1(N),η2(N,N) tridentate binding mode and two bis(diphenylphosphino)methane (dppm) ligands have been synthesized. Complexes 1-5 are singly or doubly charged dinuclear Cu(I) species with an eight-membered Cu2C2P4 ring of {Cu(μ-dppm)2Cu} unit, in which 3 and 4 adopt the boat-boat conformation, while 1, 2, and 5 display the chair-boat form. In these dimeric copper(I) complex cations, one of the two Cu(I) ions is four-coordinated, in a highly distorted N2P2 tetrahedral environment and the other is three-coordinated, in a distorted NP2 trigonal planar arrangement. All these Cu(I) complexes exhibit a comparatively weak low-energy absorption in CH2Cl2 solution, ascribed to the charge-transfer transitions with appreciable 1MLCT contribution, as suggested by time-dependent density functional theory (TDDFT) analyses. Complexes 1-5 display good emission properties in both solution and solid states at ambient temperature, which are well-modulated via structural modification of 3-(2'-pyridyl)-1,2,4-triazole, including the alteration of the substituent type (-CF3, -H, -CH3, and -C(CH3)3) and position (ortho-, meta-, and para-position). Furthermore, the variation of the substituent (-CF3 and -C(CH3)3) on the 5-site of the 1,2,4-triazolyl ring markedly influences the proton activity of the 1,2,4-triazolyl-NH, thus leading to the formation of both singly and doubly charged bimetallic Cu(I) species regulated by the NH ↔ N- conversion, resulting from NH deprotonation of the 1,2,4-triazolyl ring.

Reactivity of 4‐Pyridyltellurolate with Pd(II)/Pt(II) Complexes

AbstractReactions of 4‐pyridyltellurolate with various palladium and platinum complexes have been investigated. Treatment of MCl2(dppe) and two equivalents of Na(4‐TeC5H4N) gave cis‐[M(4‐TeC5H4N)2(dppe)] (M=Pd (1), Pt (2)). Similar reactions of MCl2(dppm) exclusively yielded unexpected products, [Pd2(μ3‐Te)(μ2‐4‐TeC5H4N)(4‐TeC5H4N)(μ‐dppm)]2 (M=Pd (3)) and [Pt{(Ph2P)2C(4‐TeC5H4N)}2] (M=Pt (4)). The cis and trans forms of [PdCl(4‐TeC5H4N)(PPh3)]2 (6 a, 6 b) could be isolated from the reaction of polymeric complex [PdCl2(4,4′‐(C5H4N)2Te2)]n (5) and PPh3. All the phosphine complexes have been characterized by NMR and X‐ray crystallography. Complex 3 contains bridging dppm ligand whereas 4 is formed via deprotonation of methylene carbon of dppm ligand.

Synthesis, Biological Evaluation, and Molecular Docking Studies on the DNA Binding Interactions of Platinum(II) Rollover Complexes Containing Phosphorus Donor Ligands.

Cyclometalated rollover complexes of the type [PtMe(κ2 N,C-bipyO-H)(L)] [bipyO-H=cyclometalated 2,2'-bipyridine N-oxide; L=tricyclohexylphosphine (PCy3 , 2 a), 2-(diphenylphosphino)pyridine (PPh2 py, 2 b), P(OPh)3 (2 c)] were synthesized by treating [PtMe(κ2 N,C-bipyO-H)(SMe2 )] (1) with various monodentate phosphine and phosphite ligands. These complexes were characterized by NMR spectroscopy, and the structure of 2 a was confirmed by single-crystal X-ray diffraction. Complex 1 was treated with bis(diphenylphosphino)methane (dppm) at a 1:1 ratio to give the corresponding [PtMe(κ2 N,C-bipyO-H)(κ1 P-dppm)] (3 b) complex, in which the dppm ligand acts as a monodentate pendant ligand. The biological activities of these complexes were evaluated against a panel of four standard cancer cell lines: lung carcinoma (A549), ovarian carcinoma (OV-90 and SKOV3), and breast carcinoma (MCF-7). Complexes 2 c and especially 3 b indicated effective potent cytotoxic activity regarding the cell lines. Electrophoresis mobility shift assays and molecular-modeling investigations were performed to determine the specific binding mode and the binding orientation of these alkylating agents to DNA. Detection of cellular reactive oxygen species was also determined.

The reactivity of trans-diiodoplatinum(II) complexes containing five and six-membered N-heterocycle ligands toward some diphosphine ligands

The known complex trans-[Pt2I2(μ-I)2(dmso)2], 1, was reacted with 2 or 4equiv of 1-methylimidazole and 4-methylpyridine as two different N-heterocycle ligands. The symmetrical cleavage of this di-nuclear structure by 2 and 4equiv of 1-methylimidazole led to formation of the complexes trans-[PtI2(1-MeIm)(dmso)], 2, and trans-[PtI2(1-MeIm)2], 4, respectively. In the case of 4-methylpyridine, the reaction of 1 with both 2 and 4equiv of the ligand ended up to the complex trans-[PtI2(4-MePy)(dmso)], 3. Also, the reactivity of the complexes 2 and 4 was investigated toward some common diphosphine ligands. The complexes 5, 6 and 7 with general formula of [PtI2(P^P)] were formed when the complexes 2 and 4 were reacted with dppm, dppe and dppp ligands respectively while the dinuclear complexes 8 and 11 with bridging diphosphine were formed using the linear dppac ligand. The complexes were fully characterized using the multinuclear (1H and 31P{H}) NMR spectroscopy and elemental analysis. The structure of typical complex 2 was further determined by X-ray crystallography. Also, DFT calculations were performed in order to gain the optimized structures and further insight into the nature of the absorption characters of the new complexes.

Synthesis, Characterization, Cytotoxic Activity, and Interactions with CT-DNA and BSA of Cationic Ruthenium(II) Complexes Containing Dppm and Quinoline Carboxylates.

The complexes cis-[Ru(quin)(dppm)2]PF6 and cis-[Ru(kynu)(dppm)2]PF6 (quin = quinaldate; kynu = kynurenate; dppm = bis(diphenylphosphino)methane) were prepared and characterized by elemental analysis, electronic, FTIR, 1H, and 31P{1H} NMR spectroscopies. Characterization data were consistent with a cis arrangement for the dppm ligands and a bidentate coordination through carboxylate oxygens of the quin and kynu anions. These complexes were not able to intercalate CT-DNA as shown by circular dichroism spectroscopy. On the other hand, bovine serum albumin (BSA) binding constants and thermodynamic parameters suggest spontaneous interactions with this protein by hydrogen bonds and van der Waals forces. Cytotoxicity assays were carried out on a panel of human cancer cell lines including HepG2, MCF-7, and MO59J and one normal cell line GM07492A. In general, the new ruthenium(II) complexes displayed a moderate to high cytotoxicity in all the assayed cell lines with IC50 ranging from 10.1 to 36 µM and were more cytotoxic than the precursor cis-[RuCl2(dppm)2]. The cis-[Ru(quin)(dppm)2]PF6 were two to three times more active than the reference metallodrug cisplatin in the MCF-7 and MO59J cell lines.

Synthesis and characterization of triosmium-bis[60]fullerene and bis(metal cluster)[60]fullerene compounds

ABSTRACTTriosmium-bis[60]fullerene compound containing dppm ligand, Os3(CO)7(dppm)(C60)2 (1), was synthesized by reaction of Os3(CO)9(μ3-η2:η2:η2-C60) and dppm ligand with Me3NO/MeCN. Reaction of Os3(CO)7(1,2-dppm)(μ3-η2:η2:η2-C60) and Re3(μ-H)3(CO)11(NCMe) produced bis(metal-cluster)[60]fullerene compound, [Os3(CO)7(1,2-dppm)](μ3-η2:η2:η2-C60)[Re3(μ-H)3(CO)9] (2). Compounds 1 and 2 were characterized by IR, NMR (1H and 31P), and Mass. Electrochemical property of 1 was confirmed by cyclic voltammetry (CV).

Newly designed luminescent di- and tetra-nuclear double rollover cycloplatinated(II) complexes

The known binuclear complex [Pt2(μ-bpy-2H)(Me)2(DMSO)2], 1, in which bpy = 2,2′-bipyridine and DMSO = dimethyl sulfoxide, was reacted with 2 equiv bis(diphenylphosphino)methane, dppm, to give the new double rollover cycloplatinated(II) complex [Pt2(μ-bpy-2H)(Me)2(κ1-dppm)2], 2, in which each metallic center bears a monodentate dppm ligand. The reaction of 2 with 2 equiv of the known monomeric cycloplatinated (II) complex [Pt(Me)(bhq-H)(SMe2)], in which bhq = 7,8-benzo[h]quinoline, gave the new unsymmetrical tetranuclear complex [{(bhq-H)(Me)Pt(μ-dppm)Pt(Me)}2(μ-bpy-2H)], 3. The complexes were fully characterized using multinuclear (1H and 31P{1H}) NMR spectroscopy and elemental analysis. Photophysical properties of the synthesized complexes were investigated and the results were confirmed by DFT calculations. The complexes 1–3 are brightly luminescent in solution and solid state. The complex 1 exhibits structured emission band, complying with the cyclometalated ligand being the centered emissive state. The complexes 2 and 3, however, exhibit unstructured emission bands, confirming a large amount of MLCT in their emissive states.

Crystalline-Amorphous-Crystalline Transformation in a Highly Brilliant Luminescent System with Trigonal-Planar Gold(I) Centers.

Photoluminescent compounds showing emission color changes in response to external stimuli have received considerable attention because of their wide range of applications. Here, we report the unique photoluminescence behavior of a digold(I) coordination system with trigonal-planar AuI centers, [Au2(dppm)3]2+ (dppm = bis(diphenylphosphino)methane). This system shows an extremely intense phosphorescence, with a quantum yield of >95% in the solid state. Both the emission color and thermal stability vary due to changing counter ions (Cl− vs. OTf−). Of particular note is the thermal crystalline-amorphous-crystalline transformation for the chloride salt, which is accompanied by drastic emission color changes. Single-crystal and powder X-ray diffractions demonstrate that the two-step transformation is induced by the loss of water molecules of crystallization with the subsequent removal of a dppm ligand to form [Au2(dppm)2]2+, which is mechanically reverted back to [Au2(dppm)3]2+.

Synthesis and properties of an unexpected trinuclear copper(I) complex supported by diphenylphosphinomethane

The reaction of CuCl2·2H2O, diphenylphosphinomethane (dppm), and tetracyanoethylene (TCNE) affords one unexpected trinuclear copper(I) complex, [CuI3(dppm)3(μ3-Cl)2]·[TCMA] 1 (TCMA: tricyanoacrylmethylate, a new compound deriving from TCNE). Structural study shows that three copper atoms are connected by dppm ligands bridging each edge to form a Cu3P6 unit. At room temperature, 1 appears photoluminescence at 447nm. And 1 also can electrocatalyze hydrogen generation from acetic acid with a turnover frequency (TOF) of 99.9mol of H2 per mole of catalyst per hour at an overpotential of 941.6mV.

Microwave-induced dppm ligand substitution in triosmium clusters: Structural and DFT evaluation of Os3 clusters containing multiply activated dppm ligands through cyclometalation, ortho metalation, and P[sbnd]C bond cleavage

Four new triosmium carbonyl complexes containing multiple dppm ligands were produced by microwave heating of solutions containing Os3(CO)12 and excess dppm. Three of these complexes, Os3(μ-H)2(CO)6(μ-dppm)[μ3-Ph2PCHP(C6H4)Ph] (2), Os3(CO)6[μ3-Ph2PCH2P(C6H4)Ph]2 (3), and Os3(μ-H)(CO)6[μ3-PhPCH2P(C6H4)Ph][μ3-PhPCH(C6H4)PPh] (4), contain two dppm ligands per Os3 unit, while the fourth, Os3(μ-H)(CO)5(dppm)[μ3-PhPCH2P(C6H4)Ph][μ3-PhPCH(C6H4)PPh] (5), is the first example of an Os3 cluster containing three dppm ligands. Microwave heating was also used to prepare the known complex Os3(μ-dppm)2(CO)8 (1) more efficiently than previously reported. The new complexes 2–5 have been characterized by IR, NMR, mass spectrometry, and X-ray crystallography. In addition, the bonding in these complexes has been examined by electronic structure calculations. All of the new complexes contain at least one dppm ligand that has undergone CH and/or CP bond activation. Complex 2 is a 48e cluster that contains one intact dppm ligand and one face-capping dppm ligand that coordinates all three osmium sites through the phosphine moieties and cyclometalated and ortho-metalated carbon atoms. Complex 3 is a 48e cluster with two ortho-metalated dppm ligands while complexes 4 and 5 are 50e clusters that possess a common metallic framework with one cyclometalated dppm ligand and one ortho-metalated dppm ligand.

Crystal structure of tris-[μ2-bis-(di-phenyl-phosphan-yl)methane-κ(2) P:P']di-μ3-iodido-tris-ilver(I) iodide-N-phenyl-thio-urea (1/1).

The title complex, [Ag3I2(C25H22P2)3]I·C7H8N2S, comprises a trinuclear [Ag3I2(C25H22P2)3]+ unit, an I− anion and one N,N′-phenyl­thio­urea mol­ecule (ptu). Two μ3-bridging I− anions are linked by three AgI ions, leading to the formation of a dicapped triangular motif with Ag⋯Ag separations in the range 3.0823 (5)–3.2999 (5) Å. Each AgI atom exhibits a distorted tetra­hedral geometry, with coordination to two I atoms and two P atoms from bis­(di­phenyl­phosphan­yl)methane ligands. In the crystal, the I− anion is linked to the ptu mol­ecule through two N—H⋯I hydrogen bonds [graph-set motif R 2 1(6)]. These N—H⋯I hydrogen bonds, in addition to weak C—H⋯S and C—H⋯I hydrogen bonds, form zigzag chains along [010]. Two of the phenyl rings of two dppm ligands are disordered over two sets of sites with refined occupancies of 0.557 (16) and 0.443 (16).