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The reactions of ReI3, Se, and KCN with Sb2O3 or Bi2O3 at elevated temperature led to the formation of two new tetrahedral clusters with mixed-ligand cluster cores {Re4Se3Sb}7+ and {Re4Se3Bi}7+. Th...

We report the synthesis of two isoreticular, mixed-ligand metal–organic frameworks (MOFs), [Cd(μ2-mia)(μ2-bpe)]n·n(DMF)0.5·n(H2O)0.5 (1) and [Cd(μ2-nia)(μ2-bpee)]n·nDMF (2), where mia = 5-methoxyis...

Mixed-ligand Cu(I) complexes have attracted attention as alternatives to the noble- and/or rare-metal complexes, because of their remarkable photofunctions. To develop mixed-ligand Cu(I) complexes with rich photofunctions, an investigation of a suitable combination of ligands has captured more and more research interests. Herein, we report the first examples of emissive heteroleptic diphosphine-disulfide Cu(I) complexes combined with diphosphine ligands. The systematic study using a series of diphosphine ligands revealed that large π-conjugated bridging moieties between the two P atoms in the diphosphine ligands result in higher light-emission performance. When the diphosphine ligand was (

A new metal–organic framework was prepared based on a mixed ligand system of the designed nitrogen-rich 3,6-bis(2-methylimidazole)pyrimidine (b2mpm) and benzophenone 4,4′-dicarboxylic acid (H2bpndc...

Advancement of the synthesis and control of the self-assembly process of new high-nucleus silver clusters with desired structures is important for both the material sciences and the many applications. Herein, three new silver clusters, 20-, 22-, and 8-nucleus, based on alkynyl ligands were constructed and their structures were confirmed by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, and Fourier-transform infrared spectroscopy (FT-IR). For the first time, the trivalent tetrahedron anion of AsO

The combined use of P(2-MeOC6H4)3 (L1) and TMEDA as ligands effectively prevents defect formation in palladium-catalyzed direct arylation polymerization (DArP) to give donor–acceptor type alternati...

In the development of metal–organic frameworks (MOFs), expansion of pore size and exploration of facile preparation conditions are considered as two major goals that are rarely realized together. T...

Different mixed-ligand Zeolitic Imidazolate Frameworks (ZIFs) with sodalite topology, i.e. isoreticular to ZIF-8, unachievable by conventional synthetic routes, have been prepared using a solvent-free methodology. In particular, the versatility of this method is demonstrated with three different metal centres (Zn, Co and Fe) and binary combinations of three different ligands (2-methylimidazole, 2-ethylimidazole and 2-methylbenzimidazole). One combination of ligands, 2-ethylimidazole and 2-methylbenzimidazole, results in the formation of SOD frameworks for the three metal centres despite this topology not being obtained for the individual ligands. Theoretical calculations confirm that this topology is the lowest in energy upon ligand mixing.

Modifying the surfaces of metal oxide nanoparticles (NPs) with monolayers of ligands provides a simple and direct method to generate multifunctional coatings by altering their surface properties. T...

Interpenetration or catenation is well explored in the network structure of metal organic frameworks, but these kinds of networks were considered as not usable for normal applications of convention...

Two novel metal–organic frameworks, namely [Cd3(bdc)(HCOO)2(tipo)2(H2O)2]·2NO3·6DMF (1) and [Zn8(OH)4(bpdc)6(tipo)4]·16DMF (2) (tipo = tris[4-(1H-imidazol-1-yl)phenyl]phosphine oxide, H2bdc = phenyl-1,4-dicarboxylic acid, H2bpdc = biphenyl-4,4′-dicarboxylic acid), have been successfully synthesized. Compound 1 exhibits a cationic 4,6-connected self-catenated framework with large 1D channels. Compound 2 features a 3,4-connected self-catenated framework with potential O donors located on the surface of the channels. Compound 1 shows a high adsorption for dichromate. Postsynthetic modification of 2 by lanthanide ions (Eu3+ and Tb3+) afforded fluorescent materials.

Reticular chemistry has been an important guiding principle for the design of metal-organic frameworks (MOFs). This approach utilizes discrete building units (molecules and clusters) that are connected through strong bonds into extended networks assisted by topological considerations. Although the simple design principle of connecting points and lines has proved successful, new design strategies are still needed to further explore the structures and functions of MOFs. Herein, we report the design and synthesis of two mixed-ligand MOFs, [(CH

Attributed to the large pore size and excellent stability, the metal–organic framework (MOF), NU-1000, which is formed by the coordination of Zr cluster and 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H4TBAPy) ligand, has been widely studied in the catalysis research field; however, only a few reports about the biomedical application of NU-1000 could be found in the open literature. In this study, a functional ligand, tetrakis(4-carboxyphenyl)porphyrin (TCPP), was introduced into NU-1000 via a postsynthetic ligand exchange method and the resulting mixed ligand MOF has an excellent photodynamic effect. Finally, in vitro and in vivo assessment about the antitumor efficacy was investigated for the first time. It demonstrates the feasibility of TCPP-substituted NU-1000 to be used for photodynamic therapy and also provides an alternative approach to enrich the function of MOF for various applications via a postsynthetic method.

We present a rapid and readily scalable methodology for the mechanosynthesis of diverse metal–organic frameworks (MOFs) in the absence of milling media typically required for other types of mechanochemical syntheses. We demonstrate the use of liquid-assisted resonant acoustic mixing (LA-RAM) methodology for the synthesis of three- and two-dimensional MOFs based on Zn(ii), Co(ii) and Cu(ii), including a mixed ligand system. Importantly, the LA-RAM approach also allowed the synthesis of the ZIF-L framework that has never been previously obtained in a mechanochemical environment, as well as its Co(ii) analogue. Straightforward scale-up from milligrams to at least 25 grams is demonstrated using the metastable framework ZIF-L as the model., We present a rapid and readily scalable methodology for the mechanosynthesis of diverse metal–organic frameworks (MOFs) in the absence of milling media typically required for other types of mechanochemical syntheses.

A multiple-photon photochemical process breaks the existing energy limitation of visible-light photocatalysis. Through careful incorporation of both bis(3,5-dicarboxyphenyl)pyridine and bis(3,5-dic...

While a plethora of protocols exist for the synthesis of sub-10-nm gold nanoparticles (AuNPs), independent control over the size and surface composition remains restricted. This poses a particular challenge for systematic studies of AuNP structure-function relationships and the optimization of crucial design parameters. To this end, we report on a modular two-step approach based on the synthesis of AuNPs in oleylamine (OAm) followed by subsequent functionalization with thiol ligands and mixtures thereof. The synthesis of OAm-capped AuNPs enables fine-tuning of the core size in the range of 2-7 nm by varying the reaction temperature. The subsequent thiol-for-OAm ligand exchange allows a reliable generation of thiol-capped AuNPs with target surface functionality. The compatibility of this approach with a vast library of thiol ligands provides detailed control of the mixed ligand composition and solubility in a wide range of solvents ranging from water to hexane. This decoupled control over the AuNP core and ligand shell provides a powerful toolbox for the methodical screening of optimal design parameters and facile preparation of AuNPs with target properties.

Three different N,N′-donor ligands with Zn(NO3)2·6H2O and two different dicarboxylates, flexible succinate (suc) and rigid fumarate (fum) afforded six different metal–organic frameworks (MOFs). Among the N,N′-donor ligands, one bent 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene (3-bpdb) gives two isostructural two-dimensional MOFs, {[Zn(3-bpdb)(suc)]·(H2O)2}n (1) and {[Zn(3-bpdb)(fum)(H2O)2]}n (2). The use of a straight N,N′-donor ligand, i.e., 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (4-bpdb), results in two three-dimensional (3D) MOFs, {[Zn4(4-bpdb)2(suc)3(OH)2]·5(H2O)}n (3) and {[Zn(4-bpdb)(fum)]·(H2O)2}n (4). Here, 3 is a pillared layer structure, whereas 4 has a 5-fold interpenetrated dimondoid network. For both the bent and straight N,N′-donor ligands an imine alike motif is embedded in the structure. When this motif is replaced by a C–C double bond by using the ligand 1,2-bis(4-pyridyl)ethylene (bpee), it produces two MOFs, {[Zn(bpee)(suc)]2·(H2O)3}n (5) and {[Zn2(bpee)2(fum)2]·(H2O)}n (6), having a...

A mixed-ligand system provides an alternative route to tune the structures and properties of metal–organic compounds by introducing functional organic or inorganic coligands. In this work, five new uranyl-based polyrotaxane compounds incorporating a sulfate or oxalate coligand have been hydrothermally synthesized via a mixed-ligand method. Based on C6BPCA@CB6 (C6BPCA = 1,1′-(hexane-1,6-diyl)bis(4-(carbonyl)pyridin-1-ium), CB6 = cucurbit[6]uril) ligand, UPS1 (UO2(L)0.5(SO4)(H2O)·2H2O, L = C6BPCA@CB6) is formed by the alteration of initial aqueous solution pH to a higher acidity. The resulting 2D uranyl polyrotaxane sheet structure of UPS1 is based on uranyl-sulfate ribbons connected by the C6BPCA@CB6 pseudorotaxane linkers. By using oxalate ligand instead of sulfate, four oxalate-containing uranyl polyrotaxane compounds, UPO1–UPO4, have been acquired by tuning reaction pH and ligand concentration: UPO1 (UO2(L)0.5(C2O4)0.5(NO3)·3H2O) in one-dimensional chain was obtained at a low pH value range (1.47–1.89) ...

Structural and chemical influences on interpenetration have been investigated through the preparation and structural analysis of a series of seven chiral coordination polymers using a phenylalanine-substituted naphthalenediimide ligand (H2PheNDI). The reaction of H2PheNDI with MnII or CdII and a range of linear dipyridyl-based coligands forms a series of coordination polymers which vary greatly in terms of their topologies and interpenetration while largely retaining a common metallomacrocyclic motif. The metallomacrocyclic motif is found in a tube-like 1D coordination polymer poly-[Cd(bipy)(OH2)(PheNDI)] (2) and a closely related 2D polythreaded network poly-{[Cd2(bipy)2(PheNDI)2][Cd(bipy)(DMF)1.5(NO3)2(OH2)0.5]} (3) which are synthesized as pure phases under slightly different conditions. The longer 1,2-di(4-pyridyl)ethylene (dpe) ligand gives rise to a 2D coordination polymer poly-[Cd4(DMF)(dpe)4(OH2)2(PheNDI)4] (5) in which the metallomacrocycles are connected only “sideways” rather than as a tube. Th...

Three new dynamic metal–organic frameworks (MOFs) namely {[Cd2(3,4-pyrdc)2(4,4′-bipy)(H2O)2]·4H2O}n (1), {[Mn2(3,4-pyrdc)2(bpee)(H2O)2]·H2O}n (2), and {[Cu2(3,4- pyrdc)2(bpp)2(H2O)4]·5H2O}n (3), based on 3,4-pyridinedicarboxylate (3,4-pyrdc) and three different N,N′-donor ligands [4,4′-bipyridine (4,4′-bipy), 1,2-bis(4-pyridyl)ethylene (bpee), and 1,3-bis(4-pyridyl)-propane (bpp)] with various divalent transition metal ions have been synthesized and characterized by single-crystal and powder X-ray diffraction and other physicochemical methods. In compounds 1 and 2, the 3,4-pyrdc ligand forms two-dimensional (2D) metal–carboxylate sheets that are connected by N,N′-donor ligands to form three-dimensional (3D) structures with water-filled channels. In compound 3, the 3,4-pyrdc ligand affords one-dimensional metal–carboxylate chains. These chains are connected by the more flexible bpp ligand to form 2D structures, which are extended to a 3D supramolecular architecture by H-bonding. Compounds 1 and 2 show a re...

Four new metal–organic frameworks (MOFs) of Cd(II) ion, [Cd(fdc)(bipy)1.5](1), [{Cd(fdc)(bpee)1.5}.3(H2O)](2), [Cd(fdc)(3bpdb)(H2O)](3), and [{Cd2(fdc)2(4bpdb)3}.1.5(4bpdb).2(H2O)](4) (where, fdc = 2,5-furandicarboxylate dianion, bipy = 4,4′-bipyridine, bpee = 1,2-bis(4-pyridyl)ethylene, 3bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, and 4bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) have been successfully synthesized using mixed ligand systems and characterized by single crystal X-ray analysis and other physicochemical studies. Structural determination revealed that compounds 1 and 4 possess a rare 2D → 3D polycatenated pillared-bilayer structure with {48.62} SP 2-periodic net topology. Compound 2 has a novel threefold interpenetrating 3D hexagonal framework structure with {46.64} sqc-net topology, whereas compound 3 features a 2D Zig-Zag network with {44.62} sql-net topology. Interestingly, compounds 1 and 4 are the first examples of Cd(II) MOFs based on fdc ligand and bipy/4bpdb spacers exhib...

A new three-dimensional Zn(II) metal–organic framework (MOF) of {[Zn4(bpydb)3(datz)2(H2O)](DMF)4(EtOH)5(H2O)8}n (1, bpydbH2 = 4,4′-(4,4′-bipyridine-2,6-diyl) dibenzoic acid, Hdatz = 3,5-diamino-1,2,4-triazole) with amino- and pyridine-functionalized pores has been successfully constructed under solvothermal conditions by using the mixed-ligand strategy, which consists of twisty 63 layers pillared by datz– ligands. The adsorption properties of this MOF were studied by CO2, N2, and CH4 sorption measurements. Compared with the analogous 4,4′-bipyridine (bpy) pillared MOF {Zn(bpydb)(bpy)}n (2) we reported earlier, the activated 1 showed enhanced CO2 sorption capacity and good sorption selectivity for CO2 over N2 and CH4 at room temperature.

Seven new [Ir(NHC)(η4-cod)(L)] complexes (4–9, 11) with NHC = bmim, emim, L = Cl–, H2O, or the water-soluble phosphines mtppms-Na, mtppts-Na3, and pta were synthesized and characterized. Na2[Ir(bmi...

To construct electronically and sterically anisotropic reaction sites of dinuclear cluster, mixed-ligand diruthenium pentahydrido complexes [Cn*Ru(μ-H)3Ru(H)2(PR3)2]+ (Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane; R = Cy (3a), iPr (3b), cyclopentyl (Cyp, 3c)) were synthesized by the reaction of [Cn*RuH(H2)2]+ (1) with Ru(H)2(H2)2(PR3)2 (R = Cy (2a) iPr (2b), Cyp (2c)). The treatment of 3a–c with KH afforded the corresponding neutral tetrahydrido complexes Cn*Ru(μ-H)3RuH(PR3)2 (R = Cy (4a), iPr (4b), Cyp (4c)). The structures of 3 and 4 were confirmed by X-ray diffraction studies. Introduction of the Cn* ligand into the cluster increased the electron density at the Cn*-ligated metal center and significantly stimulated reactivitiy toward molecular nitrogen and carbon dioxide. Complexes 3a–c reacted with molecular nitrogen to produce the terminal dinitrogen complexes [Cn*Ru(N2)(μ-H)2RuH(PR3)2]+ (R = Cy (5a), iPr (5b), Cyp (5c)), which readily underwent dimerization to form the bridging dinitrogen complexes ...

Heterometallic single-source precursors for the Pb/Fe = 1:1 oxide materials, PbFe(β-dik)4 (β-dik = hexafluoroacetylacetonate (hfac, 1), acetylacetonate (acac, 2), and trifluoroacetylacetonate (tfac, 4)), have been isolated by three different solid-state synthetic methods. The crystal structures of heterometallic diketonates 1, 2, and 4 were found to contain polymeric chains built on alternating [Fe(β-dik)2] and [Pb(β-dik)2] units that are held together by bridging M-O interactions. Heterometallic precursors are highly volatile, but soluble only in coordinating solvents, in which they dissociate into solvated homometallic fragments. In order to design the heterometallic precursor with a proper metal/metal ratio and with a discrete molecular structure, we used a combination of two different diketonate ligands. Heteroleptic complex Pb2Fe2(hfac)6(acac)2 (5) has been obtained by optimized stoichiometric reaction of an addition of homo-Fe(acac)2 to heterometallic Pb2Fe(hfac)6 (3) diketonate that can be run in solution on a high scale. The combination of two ligands with electron-withdrawing and electron-donating groups allows changing the connectivity pattern within the heterometallic assembly and yields the precursor with a discrete tetranuclear structure. In accord with its molecular structure, heteroleptic complex 5 is soluble even in noncoordinating solvents and was found to retain its heterometallic structure in solution. Thermal decomposition of heterometallic precursors in air at 750 °C resulted in the target Pb2Fe2O5 oxide, a prospective multiferroic material. Prolonging the annealing time or increasing the decomposition temperature leads to another phase-pure lead-iron oxide PbFe12O19 that is a representative of the important family of magnetic hexaferrites.

The compound [Cu(μ2-NamIDA)(2,4-dapyd)]3·3[Cu-(NamIDA)(2,4-dapyd)(H2O)]·21H2O (NamIDA = N-(1- naphtylmethyl)iminodiacetate(2-) and 2,4-dapyd = 2,4-diaminopyrimidine) is a spontaneous cocrystal with mononuclear and trinuclear metallacycle complex molecules, where extensive intermolecular H bonds play a key role.

Four mixed ligand coordination polymers [Co(BrIP)(4-BPMP)1.5·H2O]n (1), [{Zn2(BrIP)2 (HBrIP)(H3-BPMP)}·4H2O]n (2), [{Co(SDB)(3-BPMP)}·(C4H8O)·H2O]n (3) and [{Co(SDB)(4-BPMP)}·2H2O]n (4) (where 4-BPMP = 1,4-bis(4-pyridylmethyl)piperazine, 3-BPMP = 1,4-bis(3-pyridylmethyl)piperazine, H2BrIP = 5-bromoisophthalic acid, and H2SDB = 4,4′-sulfonyldibenzoic acid) have been synthesized by solvothermal methods. Crystal structure of 1 revealed that 4-BPMP ligands (present in different conformations) in conjunction with BrIP and metal nodes engender an interpenetrated two-dimensional (2D) grid-type network. Compound 2 comprises of one-dimensional metal organic ladder patterns with pendent carboxylic acid sites on HBrIP moieties. Coordination polymers 3 and 4 exhibit [Co2(SDB)2]n double chain loops containing “paddle-wheel” secondary building units tethered by 3-BPMP and 4-BPMP respectively, generating (4,4) grid-type 2D nets. Comprehensive characterization, structural analysis, and photoluminescence behavior of 1–4 a...

The novel mixed-ligand diruthenium trihydrido complex Cn*Ru(μ-H)3RuCp* (2; Cn* = 1,4,7-trimethyl-1,4,7-triazacyclononane, Cp* = η5-C5Me5) was synthesized, and its structure was determined by an X-ray diffraction study. Density functional theory (DFT) calculations for 2 revealed that the electron density at the Cn*-ligated ruthenium atom is higher than that at the Cp*-ligated ruthenium atom. Whereas the unmixed Cp*,Cp*-ligated Cp*Ru(μ-H)4RuCp* (5) exhibited no reactivity toward CO2 at 20 atm, the mixed-ligand complex 2 reacted with CO2 smoothly at atmospheric pressure and afforded the bis(μ-formato) complex Cn*Ru(μ-η1:η1-O2CH)2(μ-H)RuCp* (4) quantitatively.

A general method for the synthesis of chiral heteroleptic rhodium(II) tetracarboxylate catalysts is reported. The chlorinated TCPT unit was found to be an efficient polarity-control group, allowing the isolation of each complex from a mixture of six possible products. This approach contributes to enlarging the scope of accessible chiral Rh(II) catalysts and allowed further study of the halogen bond rigidification effect observed in chlorinated complexes.

Four isostructural chiral three-dimensional (3D) porous pillared-layer frameworks based on Co(II) and Ni(II), {[M(l-mal)(azpy)0.5]·2H2O}n (M = Co (1), Ni (2)) and {[M(l-mal)(bpee)0.5]·H2O}n(M = Co (3), Ni (4)); (l-mal = l-malate dianion, azpy = 4,4′-bisazobipyridine, and bpee = 1,2-bis(4-pyridyl)ethylene), have been synthesized using mixed ligand systems and characterized structurally. All the frameworks are homochiral, based on the chiral l-malate dianion. The bridging of l-malate with Co(II) or Ni(II) forms a two-dimensional (2D) layer of {M(l-mal)}n which is further pillared by azpy or bpee to form a 3D pillared-layer porous framework. The large rectangular channels along the crystallographic b direction (7.0 × 6.2 A2 for 1 and 2; 6.8 × 6.1 A2 for 3 and 4) are occupied by the guest water molecules. The binding of −OH and −COO groups of l-malate with the Co(II) or Ni(II) render interesting antiferromagnetic and ferrimagnetic type behavior in 1 and 2, respectively. All the frameworks show high thermal st...

4-(4-Fluorobenzoyl)-3-methyl-1-phenyl-pyrazol-5-one (HL) has been synthesized and its complexation properties in solution were examined. Mixed ligand chelate extraction of trivalent lanthanoids (La...

The complexes {[Cu(HGLYO)(NO3)(bpy)]·H2O}4 (1), {[Cu(HGLYO)(NO3)(phen)]·H2O}4 (2), and [Cu(HLACO)(ClO4)(phen)]4 (3) (bpy is 2,2′-bipyridine, phen is 1,10-phenanthroline, HGLYO is monoanionic glycol...

A nine-connected metal–organic framework [NiII2NiIII(μ3-OH)(IN)3(BDC)1.5]·xSolvent (BDC = benzene-1,4-dicarboxylate, IN = isonicotinate) has been prepared and characterized. The application of the scale-down chemistry through the use of the short and inexpensive BDC and IN ligands leads to a smaller pore size and lower surface area but little compromise in H2 sorption properties. The compound exhibits a high CO2 uptake of 73.1 cm3 g–1 (273 K and 1 atm) despite its moderate Langmuir and BET surface areas (888.3 and 571.0 m2 g–1, respectively). Its H2 uptake (1.47 wt % at 77 K and 1 atm) is also quite high, comparable to that of many materials with high surface area.

A crystal engineering based design strategy for metallogels has been demonstrated in a series of mixed ligand based CuII/CoII coordination polymers derived from two bis-pyridyl-bis-amide ligands namely N,N′-bis-(3-pyridyl)isophthalamide (L1) and N,N′-bis-(3-pyridyl)terephthalamide (L2) and various dicarboxylates. These mixed ligand coordination polymers are shown to form gels as well as X-ray quality crystals under different conditions. The crystal structures of the gel fibers in the xerogels have been determined by using powder and single-crystal X-ray diffraction data. The results support the proof of the concept based on which the metallogels are designed.

The mixed ligand system 10 mol % NiCl(2)(dppp) with 5 mol % dppf was discovered to be an extremely efficient catalyst for the neopentylglycolborylation of a diversity of electron-rich and electron-deficient aryl chlorides. Optimization showed that 5 mol % catalyst with 10% dppf was even more efficient. These results highlight the complexity of the relationship between catalyst and coligand in Ni catalysis and the benefit of combinations of mixed ligand in catalyst design.

Ligand exchange on [Au25(SCH2CH2Ph)18−] [TOA+] is studied with two chiral ligands R/S-BINAS and NILC/NIDC in THF with induction of metal-based optical activity. Under the applied condition the ligand exchange is only partial, showing that also within a mixed ligand shell significant optical activity can be induced. The ligand exchange resulted in the change of particle size as observed by UV−vis spectroscopy.

Reactions of imidazolium and benzimidazolium halides with PtBr2 and PtI2 in DMSO afford cis-Pt(II) heterocyclic carbene DMSO mixed ligand complexes 1−3 and biscarbene complexes 4−6. The reaction be...

The synthesis of ruthenium(II) and osmium(II) arene complexes of the general formula [(η6-p-cymene)M(oxine)(Hazole)]X, where M = Ru, Os; oxine = deprotonated 8-hydroxyquinoline, and Hazole = azole ...

Complex fac-[Re{κ3-H(µ-H)2B(timMe)}(CO)3] (1) (timMe = 2-mercapto-1-methylimidazolyl) promptly reacts with the neutral substrates PPh3, tBuNC and EtOOCCH2NC yielding fac-[Re{κ2-H2(µ-H)B(timMe)}(L)(CO)3] (L = PPh3(2), (tBuNC) (3), (EtOOCCH2NC) (4)). Complexes 2−4 have been fully characterized, including by variable-temperature NMR studies and X-ray diffraction analysis in the case of 2. Unlike 1, complexes 2−4 are fluxional in solution undergoing a dynamic process that accounts for the magnetic equivalence of all the B−H hydrogen atoms at room temperature. Compounds 1 and 2 were studied by DFT methods to explain the different solution behavior of the complexes anchored by (κ2-H,S) and (κ3-H,H′,S) soft scorpionates.

We report on the supramolecular synthesis and characterization of examples from three series of mixed-ligand coordination complexes composed of copper(II), a drug, and an ancillary ligand (AL). Particularly, we demonstrate how the judicious choice of an ancillary ligand affords a large degree of control over the relative lipophilicity/hydrophilicity of the complex in relation to the uncomplexed drug molecule. Furthermore, we demonstrate several important factors to consider in the design of such complexes such as the additive-constitutive nature of the partition coefficient of the ancillary ligand and the relative size of the two types of ligands.

A novel ligand-exchange route for the synthesis of amidinate-containing compounds of aluminum is explored. Syntheses of three new compounds, MeC(NiPr)2AlEt2 (4), EtC(NiPr)2AlMe2 (5), and (Me2NC(NiPr)2)2AlH (6), are presented. These mixed-ligand compounds are difficult to make in high yields by the more traditional routes of carbodiimide insertion or salt metathesis. The thermal reactivities of these compounds and their parent homoleptic compounds [MeC(NiPr)2]3Al (1), [Me2NC(NiPr)2](3)Al (2), and [EtC(NiPr)2]3Al (3) are explored in detail and analyzed with respect to their utility as potential atomic-layer-deposition precursors for aluminum-containing films. The major mechanism of thermal decomposition is found to be carbodiimide deinsertion to form aluminum alkyls or amides. Because of their thermal characteristics, both compounds 3 and 5 hold promise for use as precursors.

The extended structures of transition metal complexes of the phenanthroline-based ligand 6,7-dicyanodipyridoquinoxaline (dicnq) are reported, including the mixed ligand complex [{Cu(dicnq)Br}2H2btca] 1.7(CH 3 OH), where H 2 btca = doubly deprotonated 1,2,4,5-benzenetetracarboxylic acid, which shows 1-D coordination chains that organize into a 2-D net through hydrogen bonding. [Cu(dicnq)Br 2 ] has square-pyramidal geometry and forms 1-D zigzagging coordination chains that pack into a 2-D herringbone motif. In complex [Ni(dicnq)3]Br2·3H 2 O, the octahedral complex cations show unusual CN···π interactions and form a porous 3-D structure. Both complexes [Co(dicnq) 2 Br 2 ] and [Cu(dicnq) 2 Br 2 ][Cu(dicnq) 2 Br]Br·(CH 3 CN)-2(H 2 0) show roughly octahedral complexes that show weak C-H···N hydrogen bonding along with π-π stacking interactions to form 3-D network structures such as a 3-fold interpenetrating diamondoid structure. Complex [Ag(dicnq) 2 ](CF 3 SO 3 ) forms zigzagging chains through π-π stacking interactions.

This paper describes the synthesis of mixed Rh2(II) complexes containing bridging acetate and R,R-diphenyl-N-triflylimidazolidinone (DPTI) ligands (1, 2, and 9−19), and their function as enantioselective catalysts for the conversion of ethyl diazoacetate and terminal acetylenes to chiral cyclopropenes. Of these catalysts, 1 and 10 functioned with the highest enantioselectivity, in accord with a mechanistic model in which one of the ligand bridges is broken in the intermediate Rh−carbene complex. The synthetic results allow conclusions with regard to kinetically and thermodynamically favored pathways for the synthesis of mixed acetate−DPTI complexes. A new C2-symmetric complex having only two anti-DTBTI bridges (23) is shown to be a highly effective chiral catalyst, as expected from the model.

Metal-center-driven spontaneous resolution of a chiral coordination polymer, [Ni(SDB)(BIX)](n) (1), from achiral precursors has been probed by single-crystal X-ray diffraction and circular dichroism spectroscopy. Enantiomorphs 1P and 1M showed a parallel interpenetrated 2D → 3D chiral framework with (8(2).10) topology. Switching of the metal center under the same reaction parameters resulted in isostructural achiral and noninterpenetrating (4,4) grid-type sql networks [M(SDB)(BIX)](n), where M = Co(II), Zn(II), and Cd(II) for 2-4, respectively.

A 2D flexible metal-organic porous solid, {[Ni(1,3-adc)(bpp)(H2O)2](H2O)(EtOH)}n (1), has been synthesized using flexible organic linkers. The desolvated framework, {[Ni(1,3-adc)(bpp)]}n (1'), undergoes structural contraction and exhibits double-step hysteretic adsorption for CO2, H2O, and MeOH and single-step gate-opening behavior with EtOH. These observations are correlated with the effect of the polarity and window dimension of the pore to the corresponding adsorbate molecules.

A series of novel conjugated polymers containing mixed-ligand ruthenium complexes has been synthesized and characterized. These polymers exhibit interesting photoconductive properties. It was found that the redox and optical properties of the resulting materials were strongly affected by the structures of coordinated ligands of the ruthenium complex. The presence of σ-donating diketonate and phenolate groups in ligands substantially lowered the Ru(III/II) potentials relative to analogous polypyridyl complexes. A range of transition energies of metal-to-ligand charge transfer was observed. The photoconductivity of the polymer at long wavelengths is strongly enhanced by the metal complexes due to the metal-to-ligand charge-transfer transition.

A number of mixed ligand η6 arenechromium carbonyl complexes have been prepared and investigated for their ability to effect electronic modulation of arene chemistry. In the case of an aniline-derived system, the arenechromium carbonyl complex is able to modulate the inductive capacity of the aniline nitrogen atom and thus, regulate its anchimeric ability. In the case of 8-phenylmenthol and benzyloxazolidinone derivatives, modulation of arene π basicity is achieved, and results suggest that important vinylarene π−π interactions exist in acrylate derivatives of these chiral auxiliary systems.

A series of crystalline mixed-ligand copper(II)−aspirinate coordination complexes have been synthesized, structurally characterized, and shown to exhibit a diverse range of pharmacologically relevant properties, such as bulk solubility, solubility ratio (Swo/Sow), and partition coefficient.