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The dark blue complex [{Cp(dppe)Ru(C≡C)}3C]PF6 1 (Cp = cyclopentadienyl, dppe = 1,2-bis(diphenylphosphino)ethane) was obtained in 46 % yield by treatment of Ru(C≡CH)(dppe)Cp with CuCl/TMEDA (tetramethylethanediamine), followed by KOH and [NH4]PF6 in acetone; it was accompanied by known complexes {Cp(dppe)Ru}C≡CC≡C{Ru(dppe)Cp} 2 (22 %) and yellow [1,3-{Cp(dppe)Ru}2C4H3]PF6 3 (2.6 %). The structure of the cationic fragment of 1 in its benzene solvate consists of a central planar C attached to three C≡CRu(dppe)Cp fragments. The cation of 3 consists of a cyclobuten-1,3-diyl group bearing two Ru(dppe)Cp groups. The 13C NMR resonance of the central C in 1 is found at δ 66.11. The cyclic voltammogram of 1 contains three irreversible oxidation waves at +0.87, +0.79, and +0.25 V, together with a reversible reduction wave at −1.38 V (versus FeCp2/[FeCp2]+). The dark blue complex [{Cp(dppe)Ru(C≡C)}3C]PF6 1 was obtained in 46 % yield by treatment of Ru(C≡CH)(dppe)Cp with CuCl/TMEDA, followed by KOH and [NH4]PF6 in acetone; it was accompanied by known complexes {Cp(dppe)Ru}C≡CC≡C{Ru(dppe)Cp} 2 (22 %) and yellow [1,3-{Cp(dppe)Ru}2C4H3]PF6 3 (2.6 %). [ABSTRACT FROM AUTHOR]

The dark blue complex [{Cp(dppe)Ru(C≡C)}3C]PF6 1 (Cp = cyclopentadienyl, dppe = 1,2-bis(diphenylphosphino)ethane) was obtained in 46 % yield by treatment of Ru(C≡CH)(dppe)Cp with CuCl/TMEDA (tetramethylethanediamine), followed by KOH and [NH4]PF6 in acetone; it was accompanied by known complexes {Cp(dppe)Ru}C≡CC≡C{Ru(dppe)Cp} 2 (22 %) and yellow [1,3-{Cp(dppe)Ru}2C4H3]PF6 3 (2.6 %). The structure of the cationic fragment of 1 in its benzene solvate consists of a central planar C attached to three C≡CRu(dppe)Cp fragments. The cation of 3 consists of a cyclobuten-1,3-diyl group bearing two Ru(dppe)Cp groups. The 13C NMR resonance of the central C in 1 is found at δ 66.11. The cyclic voltammogram of 1 contains three irreversible oxidation waves at +0.87, +0.79, and +0.25 V, together with a reversible reduction wave at −1.38 V (versus FeCp2/[FeCp2]+). The dark blue complex [{Cp(dppe)Ru(C≡C)}3C]PF6 1 was obtained in 46 % yield by treatment of Ru(C≡CH)(dppe)Cp with CuCl/TMEDA, followed by KOH and [NH4]PF6 in acetone; it was accompanied by known complexes {Cp(dppe)Ru}C≡CC≡C{Ru(dppe)Cp} 2 (22 %) and yellow [1,3-{Cp(dppe)Ru}2C4H3]PF6 3 (2.6 %). [ABSTRACT FROM AUTHOR]

The precise tuning of the structural and chemical features of microporous metal–organic frameworks (MOFs) is a crucial endeavour for developing materials with properties that are suitable for specific applications. In recent times, techniques for preparing frameworks consisting of mixed-metal or ligand compositions have emerged. However, controlled spatial organisation of the components within these structures at the molecular scale is a difficult challenge, particularly when species possessing similar geometries or chemical properties are used. Here, we describe the synthesis of mixed-metal and ligand variants possessing the Mn3L3 (Mn-MOF-1; H2L = bis(4-(4′-carboxyphenyl)-3,5-dimethylpyrazolyl)methane) structure type. In the case of mixed-ligand synthesis using a mixture of L and its trifluoromethyl-functionalised derivative (H2L′ = bis(4-(4′-carboxyphenyl)-3,5-di(trifluoromethyl)pyrazolyl)methane), a mixed-ligand product in which the L′ species predominanantly occupies the pillar sites lining the pores is obtained. Meanwhile, post-synthetic metal exchange of the parent Mn3L3 compound using Fe2+ or Fe3+ ions results in a degree of cation exchange at the trinuclear carboxylate-based clusters and metalation at the pillar bispyrazolate sites. The results demonstrate the versatility of the Mn3L3 structure type toward both metal and ligand substitutions, and the potential utility of site-specific functionalisations in achieving even greater precision in the tuning of MOFs. [ABSTRACT FROM AUTHOR]

A new MOF, [Zn4O{Cu(L)2}2] (1), with a 4-fold interpenetrated 3D diamondoid structure was synthesised from in situ generated [Cu(L)2] NHC linkers. MOF 1 possesses tetrahedral Zn4O nodes, which are unusually coordinated by four pairs of carboxylates from four [Cu(L)2] linkers, and 14 Å 1-D pore channels lined with [Cu(L)2] moieties that catalyse the hydroboration of CO2 [ABSTRACT FROM AUTHOR]

A new MOF, [Zn4O{Cu(L)2}2] (1), with a 4-fold interpenetrated 3D diamondoid structure was synthesised from in situ generated [Cu(L)2] NHC linkers. MOF 1 possesses tetrahedral Zn4O nodes, which are unusually coordinated by four pairs of carboxylates from four [Cu(L)2] linkers, and 14 Å 1-D pore channels lined with [Cu(L)2] moieties that catalyse the hydroboration of CO2 [ABSTRACT FROM AUTHOR]

The binuclear complexes {Cp*(dppe)M}2{μ-CCC[C(CN)2]C[C(CN)2]CC} (2Fe, M = Fe; 2Ru,M = Ru) and {Cp*(dppe)Fe}{CCC[C(CN)2]C[C(CN)2]CC}{Ru(dppe)Cp*} (2FeRu) were obtainedby treatment of the binuclear precursorsCp*(dppe)M-CCCCCC-M′(dppe)Cp* (M =M′ = Fe, 1Fe; M = M′ = Ru, 1Ru; M = Fe, M′ = Ru, 1FeRu) with TCNE in CH2Cl2at 20 °C. Complexes 2Feand 2FeRuwere isolated as deep purple powders (82% and 87% yields,respectively), and 2Ruwas isolated as a brown-yellowsolid (55%). The paramagnetic salt [2FeRu][C3(CN)5]was also isolated in 51% yield. The structural and electronic propertiesof the new compounds were investigated by 1H, 13C, and 31P NMR, XRD analysis, cyclic voltammetry, IR andUV–vis, EPR, and NIR spectroscopies. The experimental dataclearly show that the insertion of the central −CC–triple bond of [M]–C6–[M] into tetracyanoethene(TCNE) dramatically decreases the electronic interaction between themetal termini. NIR spectroscopy of the salt [2FeRu][C3(CN)5]demonstrated that the coupling between the iron andruthenium centers is not completely removed by addition of TCNE to [1FeRu]+, but has produced a very strong attenuationof the electronic coupling from Hab=0.50 eV to Hab= 0.03 eV. [ABSTRACT FROM AUTHOR]

The binuclear complexes Cp*(dppe)FeCCCCCCM(dppe)Cp*(6, M = Fe; 8, M = Ru) were obtained ingood yield by treatment of the iron chloro complex Cp*(dppe)Fe–Cl(5) in the presence of KF with the bis(silylated) hexatriyneMe3SiCCCCCCSiMe3andthe ruthenium complex Cp*(dppe)RuCCCCCCSiMe3(7), respectively. The oxidized species 6(PF6)n(n= 1, 2) and 8(PF6)were obtained in ca. 80%yield by treatment of the parent neutral compounds with 1 or 2 equivof [Cp2Fe](PF6) in THF or dichloromethane at−78 °C. The CV of these compounds show three reversiblewaves with a separation larger than 0.5 V. The salts 6(PF6)n(n= 1, 2), and 8(PF6)were characterized by XRD. Quantumchemistry calculations performed at the DFT level on the oxidizedspecies show a strong contribution of the −C6–spacer to the delocalization of the spin density. IR spectra analyzedwith the support of TD-DFT calculations are consistent with the delocalizationof the odd electron on the fast IR time scale for the two mixed-valencecomplexes 6(PF6)and 8(PF6). CombinedESR measurements on rigid glass and on single crystal samples clearlyestablish that the electronic properties of MV species and particularlytheir magnetic anisotropies depend on the conformation of the molecules.In the case of the doubly oxidized species 6(PF6)2, which carriestwo unpaired electrons, it is shown that the singlet vs triplet groundstates can be inverted by the rotation of one metal end with respectto the other around the all-carbon chain axis. Very strong NIR bandsare found for the symmetric 6(PF6)and nonsymmetric 8(PF6)MV (mixed-valence) derivatives allowing thedetermination of very large electronic couplings (Hab= 3070 and 4025 cm–1, respectively). [ABSTRACT FROM AUTHOR]

One approach to exploit metal-organic frameworks (MOFs) as heterogeneous catalyst platforms requires the development of materials containing groups that can be utilised to anchor a catalytic moiety into the links within the structure. Here we report the synthesis of the first integrated triazolium-containing MOF linker and the first MOFs containing linkers of this type. 1,4-Bis(4-benzoic acid)-1-methyl-1H-1,2,3-triazolium chloride, H[sub 2]L1[sup Me], was synthesised in three steps by a 'click' reaction of methyl 4-ethynylbenzoate with methyl 4-azidobenzoate, methylation using methyl triflate, followed by ester hydrolysis in overall 74% yield. The equivalent neutral triazole precursor, 1,4-bis(4-benzoic acid)-1 H-1,2,3-triazole hydrochloride, H[sub 2]L1(HCl), was also prepared and a comparison of the chemistry with Zn(NO[sub 3])[sub 2]-6H[sub 2]O and Cu(NO3)[sub 2] л 3H[sub 2]O is presented. The results support the use of reaction conditions to control interpenetration and provide additional evidence that the charge on structurally similar ligands can drastically alter the types of structures that are accessible due to the requirements for charge balance in the final product. [ABSTRACT FROM AUTHOR]

Two series of metal-polyynyl complexes of iron and rutheniumofgeneral formula [{M(dppe)Cp*}–(CC)n–R]0/(M = Fe, Ru; R = H, Ph, SiMe3, Au(PPh3); n= 1–3), have beensynthesized, characterized, and theoretically analyzed. The resultsprovide a comprehensive description of the effect of the length ofthe conjugated carbon chain and the role of the nature of the metalatom and the terminal substituent on their neutral and oxidized states.For the latter, the spin density found on the carbon chain is a sourceof instability; e.g., for R = Au(PPh3), the oxidized compoundsare much more accessible electrochemically than the rest of the seriesbut are susceptible to radical attack. Of particular interest is theuse of joint experimental and theoretical EPR studies, which allowelucidation of the differences of behavior within the two series.It reveals that the atomic spin density on the metal is not a sufficientcriterion to evaluate EPR anisotropy but that the specific nodal propertiesof the frontier spin–orbitals highly influence the EPR components.The localization of the spin density on specific carbon atoms of theconjugated chain (even numbered) opens up the possibility of buildingextended systems by targeted radical reactions. [ABSTRACT FROM AUTHOR]

The reaction of tetracyanoquinodimethane (TCNQ) withRu(CCCCH)(dppe)Cp*(5) at the outer (from Ru) CC triple bond givesη1-(butadienyl)ethynyl Ru{CCC[CHC(CN)2]C6H4C(CN)2}(dppe)Cp (8), which reacts with a second equivalentof diynyl-Ru complex to give {Ru(dppe)Cp*}{CCC[C6H4C(CN)2]CHCHC[C(CN)2]CC}{Ru(dppe)Cp*} (9). The Ph-substitutedcomplexes M{CCCCPh}(dppe)Cp* (M = Fe 6-Fe, Ru 6-Ru) and Ru{(CC)3Ph}(PPh3)2Cp (7) react with TCNQ to give theη1-(butadienyl)ethynylsM{CCC[CPhC(CN)2]C6H4C(CN)2}(dppe)Cp (10-Fe, 10-Ru) and Ru{CCC[C(CCPh)C(CN)2]C6H4C(CN)2}(PPh3)2Cp (11), respectively.Single-crystal X-ray diffraction molecular structure determinationsfor 8–11have been carried out. Inthe Fe series, we suggest that the initial step of the mechanism involveselectron transfer to form the [TCNQ]−•saltof the diynyl-iron cation, followed by C–C bond formation togive a zwitterionic intermediate. Isolated products can be rationalizedby further reaction involving [2 2]-cycloaddition of one of theCC(CN)2groups of TCNQ to a CC triple bondof the metal poly-ynyl complex and a subsequent ring-opening reactionof the resulting (unobserved) cyclobutenyl intermediate. On the basisof X-ray diffraction data, redox potential determinations, and 57Fe Mössbauer and UV–vis spectroscopies, theelectronic structures of the new compounds contain significant contributionsfrom polarized mesomers involving charge transfer from the electron-richmetal–ligand fragment to the cyanocarbon ligand via the conjugatedunsaturated carbon linker. [ABSTRACT FROM AUTHOR]

Reactions of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with the alkynyl-iron and ruthenium complexes [M](C=CR) {[M] = Fe(dppe)Cp*, Ru(PPh[sub 3])[sub 2]Cp; R = H, Ph} are described. The iron complex Fe(C=CPh)(dppe)Cp* (2a) is oxidized by TCNQ to give the kinetically stable salt [2a[sup * +]][TCNQ][sup * -] . Displacement of [TCNQ][sup * -] is achieved by ionic metathesis upon addition of KPF[sub 6] to produce [2a[sup * +]]PF[sub 6]. In contrast, Fe(C=CH)(dppe)Cp* (2b) reacted with TCNQ to give a mixture of compounds containing Fe(=C=CH[sub 2])(dppe)Cp* (3a), {Fe(dppe)Cp*}[sub 2](μ-C=CHCH=C) (3b), and the zwitterionic complex Fe[sup +]{=C=CHC(CN)[sub 2]C[sub 6]H[sub 4]C[sup -](CN)[sub 2]}(dppe)Cp* (3c). In contrast, the reaction of TCNQ with Ru(C=CR)(PPh[sub 3])[sub 2]Cp (4a, R = Ph; 4b, R = H) gave selectively the zwitterionic vinylidenes Ru[sup +]{=C=CRC(CN)[sub 2]C[sub 6]H[sub 4]C[sup -](CN)[sub 2]}(PPh[sub 3])[sub 2]Cp (5a, R = Ph; 5b, R = H), in which the Ru centres are positively charged and the counter-anion is located on the further C(CN)[sub 2] group. On heating 5b, elimination of HCN affords Ru{C=CC(CN)=C[sub 6]H[sub 4]=C(CN)[sub 2]}(PPh[sub 3])[sub 2]Cp (1), while similar treatment of 5a gives Ru{[sup 3]-C(CN)[sub 2]CPh=C[sub 6]H[sub 4]=C(CN)[sub 2]}(PPh[sub 3])Cp (6) with loss of PPh[sub 3]. X-ray structures of 1, 5a, and 6, cyclic voltammetry, and UV-vis spectroscopy of 1 provided evidence for the electronic structures of the new complexes. Organometallics with various donor-bridge-acceptor arrangements allow investigation of the key factors affecting the properties of these multifunctional molecular systems. Herein, reactions of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with Fe(C=CR)(dppe)Cp* and Ru(C=CR)(PPh[sub 3])[sub 2]Cp (R = H, Ph) are described. Formed are the mono-cation (by oxidation in the iron series), zwitterionic complexes, and complexes formed by regioselective [2 + 2]-cycloaddition and subsequent ring-opening reactions; elimination of HCN (in the ruthenium series) was also observed. [ABSTRACT FROM AUTHOR]

The complex Ru{CCC(CN)C(CN)2}(dppe)Cp* (1), containing the new tricyanovinylethynyl (3,4,4-tricyanobut-3-en-1-ynyl) ligand, undergoes ready substitution of the 3-cyano group by nucleophiles (Nu) such as H, Me, Pri, Bu, But, mesityl, OMe, OBut, OCH2CHCH2, NHEt, NEt2, and PPh2 to give Ru{CCC(Nu)C(CN)2}(dppe)Cp*. The X-ray diffraction structures of several of the resulting complexes are reported and, for the mesityl and PPh2 products, show that isomerization to the 3,5-dimethylbenzyl and oxidation to the phosphine oxide have respectively occurred. [ABSTRACT FROM AUTHOR]

Post-synthetic modification of metal-organic frameworks (MOFs) facilitates a strategic transformation of potentially inert frameworks into functionalized materials, tailoring them for specific applications. In particular, the post-synthetic incorporation of transition-metal complexes within MOFs, a process known as 'metalation', is a particularly promising avenue towards functionalizing MOFs. Herein, we describe the post-synthetic metalation of a microporous MOF with various transition-metal nitrates. The parent framework, 1: , contains free-nitrogen donor chelation sites, which readily coordinate metal complexes in a single-crystal to single-crystal transformation which, remarkably, can be readily monitored by X-ray crystallography. The presence of an open void surrounding the chelation site in 1: prompted us to investigate the effect of the MOF pore environment on included metal complexes, particularly examining whether void space would induce changes in the coordination sphere of chelated complexes reminiscent of those found in the solution state. To test this hypothesis, we systematically metalated 1: with first-row transition-metal nitrates and elucidated the coordination environment of the respective transition-metal complexes using X-ray crystallography. Comparison of the coordination sphere parameters of coordinated transition-metal complexes in 1: against equivalent solid- and solution-state species suggests that the void space in 1: does not markedly influence the coordination sphere of chelated species but we show notably different post-synthetic metalation outcomes when different solvents are used.This article is part of the themed issue 'Coordination polymers and metal-organic frameworks: materials by design'., (© 2016 The Author(s).)