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The design and development of functional materials with real-life applications are highly demanding. Understanding and controlling inter- and intra-molecular interactions provide opportunities to design new materials. A judicious manipulation of the molecular structure significantly alters such interactions and can boost selected properties and functions of the material. There is burgeoning evidence of the beneficial effects of non-covalent interactions (NCIs), showing that manipulating NCIs may generate functional materials with a wide variety of physical properties leading to applications in catalysis, drug delivery, crystal engineering

The use of organic additives presents the greatest versatility and control of zeolite synthesis in order to prepare novel architectures for desired applications. Despite this prospect, there is little clarity of how organic additives are involved in framework assembly and the range of behaviours that are available. To address this issue, we have considered zeolites RHO and ZK-5 which can both be prepared using 18-crown-6 ether as an additive. Previously, this additive has shown to employ different structure directing behaviours to assemble a variety of zeolites. We have used high resolution powder X-ray diffraction and Rietveld refinement to determine structural models for zeolites RHO and ZK-5 with 18-crown-6 ether occluded in the framework. In doing so, we can observe the identity, location and orientation of the occluded additive and reason the structure directing behaviour in synthesis. We report that the isolated 18-crown-6 ether molecule is involved in the assembly of zeolite RHO, and for zeolite ZK-5 it is the K+ coordinated macrocation. In both cases the relevant additive is disordered in the framework, suggesting that they behave as space-filling species that stabilise the formation of the α-cage.

Two new organo-europium complexes (OEuCs) [Eu(tfac)3(TB-Im)] (Eu1) [Eu(hfac)3(TB-Im)] (Eu2) incorporating fluorinated (hexafluoroacetylacetone; Hhfaa) or hemi-fluorinated (trifluoroacetylacetone; Htfac) β-diketones together with the large bite angle N^N ligand (2-(4-thiazolyl)benzimidazole; TB-Im) have been synthesized and characterized. The structure of the complexes has been established by single crystal X-ray diffraction (SC-XRD) analysis and shows that the coordination sphere is composed of a EuO6N2 core (octacoordinated). Continuous shape measures (CShMs) revealed that the geometry around Eu(III) is trigonal dodecahedral with approximate D2d-symmetry. Efficient red emission is observed for both the complexes in solution with a fairly large photoluminescence quantum yield (PLQY (QLEu) = 39.00–47.00%). Furthermore, by utilizing the experimental photoluminescence (PL) data and theoretical modelling employing density functional theory (DFT) in conjunction with LUMPAC, energy transfer (ET) and back energy transfer rates were calculated, and an ET mechanism for the sensitized PL is proposed and discussed in detail. Finally, the complexes were used as an emitting layer (EML) to fabricate 20 organic light emitting diodes (OLEDs) by varying the doping concentration. Interestingly, both the complex-based OLEDs at 4 wt% doping concentration display white electroluminescence (EL) with the brightness (B) = 100.5–364.1 cd m−2 at very low turn-on voltage (Vturn-on) = 3.9–4.6 V. The overall electroluminescence performance of Eu1 and Eu2 is higher than that of the reported europium based single component white-OLEDs.

The visualization of chemical processes that occur in the solid-state is key to the design of new functional materials. One of the challenges in these studies is to monitor the processes across a range of timescales in real-time. Here, we present a pump-multiprobe single-crystal X-ray diffraction (SCXRD) technique for studying photoexcited solid-state species with millisecond-to-minute lifetimes. We excite using pulsed LEDs and synchronise to a gated X-ray detector to collect 3D structures with sub-second time resolution while maximising photo-conversion and minimising beam damage. Our implementation provides complete control of the pump-multiprobe sequencing and can access a range of timescales using the same setup. Using LEDs allows variation of the intensity and pulse width and ensures uniform illumination of the crystal, spreading the energy load in time and space. We demonstrate our method by studying the variable-temperature kinetics of photo-activated linkage isomerism in [Pd(Bu4dien)(NO2)][BPh4] single-crystals. We further show that our method extends to following indicative Bragg reflections with a continuous readout Timepix3 detector chip. Our approach is applicable to a range of physical and biological processes that occur on millisecond and slower timescales, which cannot be studied using existing techniques.

Here, a new tripodal tricarboxylic acid ligand, 4,4′-(4′-(4′-carboxy-[1,1′-biphenyl]-4-yl)-[2,2′:6′,2′′-terpyridine]-5,5′′-diyl)-dibenzoic acid (H3cbt), was synthesised using a three-step convergent strategy. Subsequent reactions with zinc(ii) nitrate hexahydrate yielded three metal-organic frameworks (MOFs). The three MOFs, [Zn(Hcbt)]·4DMF (1), [Zn(Hcbt)]·4DMSO·1.5H2O·DMF (2), and [Zn(Hcbt)]·2DMF·3H2O (3), each adopt flexible interdigitated 2D net topologies. Framework 1 has DMF-filled channels that retain porosity upon desolvation, with a measured BET surface area of 248 m2 g-1. Framework 2 possesses larger DMSO-containing channels that collapse upon desolvation, resulting in near-equivalent porosity values to framework 1. In silico calculations and topological considerations determined using the geometric simulation software GASP dictate that framework 2 can feasibly alter conformation to approximate 1, but cannot perfectly replicate the interdigitated motif. Framework 3 formed when wet solvents were used to synthesise 1. Interestingly, the interdigitated structure of 3 contains a unique carboxylate binding mode that precludes its subsequent adoption by either 1 or 2 upon their exposure to water. This diverse array of structural considerations recommends this MOF family for modelling using GASP. Interrogating frameworks 1-3 using this software provided insights that justified experimentally observed conformational trends, as well as barriers to interconversion between members of this MOF family. In a broader sense, this work demonstrates the wider applicability of GASP software to modelling structural changes within flexible MOF materials.

A series of mono-, di-, and poly(platina-ynes) incorporating stilbene spacer units with the formulae trans-[R–CC–Pt(PBu3)2-CC–R] (R = (E)-1,2-diphenylethene), trans-[(Ph)-(Et3P)2PtCC–R–CCPt(PEt3)2(Ph)] (R = (E)-1,2-diphenylethene), and trans-[–(PnBu3)2PtCC–R–CC–]n (R = (E)-1,2-diphenylethene), respectively, have been synthesized and characterized to explore the effects of ligand topology on the photoisomerization and photophysical properties of these materials. The structural and photophysical properties of the complexes have been investigated and compared with those of the previously reported mono-, di- and poly(platina-ynes) incorporating azobenzene spacers. We found that the organometallic species 1M, 2M and 1P undergo topology-dependent reversible trans-to-cis photoisomerization in CH2Cl2 solution. Computational modelling supported the experimental findings.

Pt(II) di-ynes and poly-ynes incorporating 5,5’- and 6,6’-disubstituted 2,2’-bipyridines were prepared following conventional Sonogashira and Hagihara dehydrohalogenation reaction protocols. Using Pt(II) dimers and polymers as a rigid-rod backbone, four new hetero-bimetallic compounds incorporating Re(CO)3Cl as a pendant functionality in the 2,2’-bipyridine core were obtained. The new hetero-bimetallic Pt-Re compounds were characterized by analytical and spectroscopic techniques. The solid state structures of a Re(I)-coordinated diterminal alkynyl ligand and a representative model compound were determined by single-crystal X-ray diffraction. Detailed photo-physical characterization of the hetero-bimetallic Pt(II) di-ynes and poly-ynes was carried out. We find that the incorporation of the Re(CO)3Cl pendant functionality in the 2,2’-bipyridine-containing main-chain Pt(II) di-ynes and poly-ynes has a synergistic effect on the optical properties, red shifting the absorption profile and introducing strong long-wavelength absorptions. The Re(I) moiety also introduces strong emission into the monomeric Pt(II) di-yne compounds, whereas this is suppressed in the poly-ynes. The extent of the synergy depends on the topology of the ligands. Computational modelling was performed to compare the energetic stabilities of the positional isomers and to understand the microscopic origin of the major optical absorptions. We find that 5,5’-disubstituted 2,2’-bipyridine systems are better candidates in terms of yield, photophysical properties and stability than their 6,6’-substituted counterparts. Overall, this work provides an additional synthetic route to control the photo-physical properties of metalla-ynes for a variety of optoelectronic applications.

We report the structural, spectroscopic, and computational studies of two new Re(I) tricarbonyl complexes bearing 2,3,6,7-tetraphenyl-1,4,5,8-tetraazaphenanthrene (Ph4TAP) and 4,5-diazafluoren-9-one (dafone) having a coordinated perrhenate group obtained via in situ superoxidation of Re(I) to Re(VII); intramolecular and intermolecular n → π* interactions are dominant and stabilize the molecular geometry and crystal packing.

Presently, there is little clarity concerning how organic additives control structure formation in the synthesis of zeolite catalysts. Such ambiguity is a major obstacle towards synthesis design of new bespoke zeolites with intended applications. Herein, we have applied inelastic neutron scattering (INS) spectroscopy to experimentally probe the nature of organic-framework interactions, which are crucial in understanding structure direction. With this technique we have studied the dynamics of 18-crown-6 ether, which can be used as an additive to direct the formation of four zeolites: Na-X, EMC-2, RHO and ZK-5. We observed significant softening of the 18-crown-6 ether molecule's dynamics upon occlusion within a zeolite host, with a strong influence on both the circular and radial vibrational modes. Furthermore, there is a strong correlation between the size/geometry of the zeolite framework cages and perturbations in the dynamics of the 18C6 oxyethylene chain. We propose that the approach used herein can be used to study other zeolites, and hence gain a more comprehensive view of organic-framework interactions.

The photophysical properties of two previously synthesized, highly efficient, bright red emitting complexes [Eu(btfa)3DPEPO] (CIE, 0.672; 0.326) (Eu-1) and [Eu(nta)3DPEPO] (CIE, 0.673; 0.326) (Eu-2) (btfa = 4,4,4-trifluoro-1-phenyl-1,3-butanedione, nta = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione and DPEPO = bis(2-(diphenylphosphino)phenyl)ether oxide) are reported. The complexes have been used as dopants to fabricate several single and double emitting layer (EML) electroluminescent (EL) devices. At the optimum doping concentration of 4 wt%, the single EML device of Eu-1 exhibited a pure red color with an external quantum efficiency (EQE) of 2.9% and a maximum brightness (B) = 1320 cd m−2, maximum current efficiency (ηc) = 4.08 cd A−1, maximum power efficiency (ηp) = 3.37 lm W−1 with a very low turn-on voltage (Vturn-on) = 3.8 V. Importantly, the single EML device of Eu-2 at the optimum doping concentration exhibited pure red EL with EQE of 6.0% with the best EL performance: B = 2108 cd m−2, ηc = 8.45 cd A−1, and ηp = 6.98 lm W−1 at a very low Vturn-on = 3.5 V. The performances of this device are among the best reported for devices incorporating a europium complex as a red emitter. Furthermore, the EL performances were achieved at the current density of 10 mA cm−2, thereby alleviating a serious efficiency roll-off as a major obstacle to the development of Eu-complex based EL devices.

A new homodinuclear complex [Eu(btfa)3]2bpm (1) was synthesized incorporating 4,4,4-trifluoro-1-phenyl-1,3-butanedione (btfa) as the primary and 2,2′-bipyrimidine (bpm) as the auxiliary ligand. The complex was characterized by analytical and spectroscopic techniques, with special emphasis on the crystal structure and photoluminescence (PL) properties, both experimentally and theoretically. Single crystal X-ray diffraction (SCXRD) analysis reveals that the two Eu(III) ions in 1 are eight coordinate, where the bpm behaves as a N4 donor linking the two Eu(III) ions symmetrically. Each Eu(III) ion displays a distorted square antiprismatic (DSAP, D4d) coordination geometry. Complex 1 displayed bright red emission with (CIE)x,y color coordinates = 0.670; 0.330 and an absolute photoluminescence quantum yield (PLQY) of 54.4%. The theoretical intensity parameters (Ω2 and Ω4), radiative (AR) and non-radiative (ANR) decay rates, intrinsic quantum yield (QEuEu), sensitization efficiency (ηsen) and PLQY were assessed using the LUMPAC software and showed very good agreement with the experimental values. Based on these, an energy transfer (ET) mechanism is proposed and discussed. Moreover, 1 was used as an emitter to fabricate single- and double-emitting layer (EML) red-emitting electroluminescent devices. Double-EML device at the optimum doping concentration of 4.0 wt% displayed impressive EL performances, brightness (B) = 812 cd m−2, maximum current efficiency (ηc) = 3.97 cd A−1, maximum power efficiency (ηp) = 3.89 lm W−1, and external quantum efficiency (EQE) = 2.8% at very low Vturn-on = 3.2 V with (CIE)x,y = 0.662, 0.321 which is close to the standard red color recommended by NTSC (0.67, 0.33).

A new samarium complex [Sm(hfaa)3(Py-Im)] (ML) was synthesized by utilizing hexafluoroacetylacetone (hfaa) and 2-(2-pyridyl)benzimidazole (Py-Im) as coordinating ligands. Single crystal X-ray analysis shows that in the solid-state the complex dimerizes through intermolecular hydrogen-bonding with N-H?O (2.127 Å) and N-H?F (2.576 Å) interactions. The complex in the solid-state displayed highly monochromatic brilliant red emission with Commission International de I'Eclairage (CIE) color coordinates of 0.6532; 0.3336, with a remarkably long luminescence lifetime (?exp. ? 204.47 ± 4.043 ?s) and a high intrinsic quantum yield (QSmSm ? 6.60%). Furthermore, the complex in different organic media displayed color tunability from orange (CIE; 0.6071; 0.3568) to violet (CIE; 0.3634; 0.2144) with ?exp. from 105.50 ± 0.143 to 14.27 ± 0.033 ?s. Hybrid and flexible thin films obtained by doping different concentrations (1%, 2%, 4% and 6%) of the complex into the poly(urethane) (PU) polymer matrix also exhibited color tunability from violet (CIE; 0.3380; 0.2162) to light orange (CIE; 0.5666; 0.3408). White light emission from a 1% doped thin film of the complex was realized by changing the excitation wavelength. Thus, the new material could be a potential candidate for the fabrication of full-color display devices and for solid-state lighting (SSL) applications. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. F.279 Engineering and Physical Sciences Research Council: EP/K004956/1 SR/SQU/SCI/CHEM/16/02 MSK acknowledges His Majesty’s Trust Fund for Strategic Research (Grant No. SR/SQU/SCI/CHEM/16/02) for funding. RI thanks the HM’s Trust Fund for a post-doctoral fellowship. The authors acknowledge the Faculty of Arts and Sciences, Ondokuz Mayıs University, Turkey, for the use of the Stoe IPDS 2 diffractometer (purchased under grant F.279 of the University Research Fund). PRR is grateful to the Engineering and Physical Sciences Research Council (EPSRC) for continued support (Grant EP/K004956/1).

Two new mixed ligand complexes [Eu(tfac)3(DPEPO)] (Eu-1) and [Tb(tfac)3(DPEPO)] (Tb-2) incorporating trifluoroacetylacetone (Htfac) and bis(2-(diphenylphosphino)phenyl)ether oxide (DPEPO) were synthesized in gram-scale quantities and used as emitters to fabricate single- and double-EML (light-emitting layer) electroluminescence (EL) devices. The single-EML device with the structure: ITO/HAT-CN (6 nm)/HAT-CN (0.2 wt%):TAPC (50 nm)/Eu-1 (1–6 wt%): 26DCzPPy (10 nm)/Tm3PyP26PyB (50 nm)/LiF (1 nm)/Al (100 nm) showed light red (CIE, x: 0.574; y: 0.275) emission for the Eu-1 based EL devices due to the presence of a host emission with a brightness of 1274 cd m−2, current efficiency (ηc), power efficiency (ηp) and external quantum efficiency (EQE) of 0.58 cd A−1, 0.68 lm W−1, and 0.70%, respectively. The single-EML device for the Tb-2 complex with the same device structure displayed white-light emission. The optimized single-EML device of Tb-2 with 14.0 wt% doping concentration showed an impressive EL performance with brightness of 1637 cd m−2, ηc ≈ 3.05 cd A−1, ηp ≈ 2.80 lm W−1, EQE ≈ 1.4%, Vturn-on ≈ 3.1 V, respectively. This is the first report of single component white organic light emitting diode (W-OLED) fabricated from an organo-Tb(III) complex. The W-OLEDs show low turn-on voltages (Vturn-on) ≈ 3.1 V and are thus advantageous in lowering the power consumption of the OLED display.

Two unique series of lanthanide complexes [Ln(Ph3PO)4(NCS)3] (Ln = La-Tb, except Pm) and [Ln(Ph3PO)3(NCS)3] (Ln = Sm-Lu, Y) have been structurally characterised. The isomorphous series [Ln(Ph3PO)4(NCS)3] crystallises in the monoclinic centrosymmetric space group P21/c, and the metals display a capped octahedral coordination geometry. In contrast, the isomorphous series [Ln(Ph3PO)3(NCS)3] (Ln = Sm-Lu, Y) crystallise in the non-centrosymmetric space group R3, with the metal displaying an octahedral coordination geometry; the fac-isomer being observed in all cases. Intriguingly, for the metals Sm-Tb both the seven and six coordinate complexes can be isolated from the respective synthetic routes suggesting a structural equilibrium in solution. An analysis of the distortions of the ligand polyhedron in the two series using the continuous shape measurement (CShMs) method suggests trends across the series relating to the fit of the ligands with the size of the lanthanide ions.

A new heterotrinuclear (d-f-d) complex [Eu(btfa)31c] (btfa = 4,4,4-trifluoro-1-phenyl-1,3-butanedione and 1c = [(Ph)(Et3P)2Pt-C[triple bond, length as m-dash]C-R-C[triple bond, length as m-dash]C-Pt(Et3P)2(Ph)] (R = 2,2'-bipyridine-5,5'-diyl) has been synthesized by utilizing the N,N-donor sites of the organometallic chromophore. The complex was characterized by analytical and spectroscopic methods. Photophysical properties of the complex were analysed in detail using both steady-state and time-resolved emission and excitation spectroscopy. The optical absorption spectrum of the complex is dominated by the spin allowed π-π* transitions of the btfa and 1c units in the UV-visible region (200-418 nm) and thus is excitable over a wide range of wavelengths across the UV into the visible region of the electromagnetic spectrum. The complex displays typical red Eu(iii) emission when excited at 345 nm. However, it also shows green emission when excited at 464 nm and, thus could be an interesting candidate for full colour display applications. The change in the colour could be a result of the high value of the energy back-transfer rate (6.73 × 105 s-1) from the triplet state of the organometallic chromophore to the 5D1 state of Eu(iii). Judd-Ofelt (J-O) intensity parameters (Ω2 and Ω4), radiative (AR), non-radiative (AR) decay rates and intrinsic quantum yield (Q) have been calculated.

In this chapter the development of time-resolved crystallography is traced from its beginnings more than 30 years ago. The importance of being able to “watch” chemical processes as they occur rather than just being limited to three-dimensional pictures of the reactant and final product is emphasised, and time-resolved crystallography provides the opportunity to bring the dimension of time into the crystallographic experiment. The technique has evolved in time with developments in technology: synchrotron radiation, cryoscopic techniques, tuneable lasers, increased computing power and vastly improved X-ray detectors. The shorter the lifetime of the species being studied, the more complex is the experiment. The chapter focusses on the results of solid-state reactions that are activated by light, since this process does not require the addition of a reagent to the crystalline material and the single-crystalline nature of the solid may be preserved. Because of this photoactivation, time-resolved crystallography is often described as “photocrystallography”. The initial photocrystallographic studies were carried out on molecular complexes that either underwent irreversible photoactivated processes where the conversion took hours or days. Structural snapshots were taken during the process. Materials that achieved a metastable state under photoactivation and the excited (metastable) state had a long enough lifetime for the data from the crystal to be collected and the structure solved. For systems with shorter lifetimes, the first time-resolved results were obtained for macromolecular structures, where pulsed lasers were used to pump up the short lifetime excited state species and their structures were probed by using synchronised X-ray pulses from a high-intensity source. Developments in molecular crystallography soon followed, initially with monochromatic X-ray radiation, and pump-probe techniques were used to establish the structures of photoactivated molecules with lifetimes in the micro- to millisecond range. For molecules with even shorter lifetimes in the sub-microsecond range, Laue diffraction methods (rather than using monochromatic radiation) were employed to speed up the data collections and reduce crystal damage. Future developments in time-resolved crystallography are likely to involve the use of XFELs to complete “single-shot” time-resolved diffraction studies that are already proving successful in the macromolecular crystallographic field.

The current discussion on whether scandium, yttrium and lanthanum should represent Group 3 in the Periodic Table or whether lutetium should replace lanthanum in the group has prompted us to further explore the structural chemistry of the Group 3 elements and compare the coordination numbers and coordination geometries adopted. The steric and electronic properties of the coordinated ligands have a major influence on the structures adopted. We report the synthesis and crystal structure determination of an unusual dinuclear scandium complex [(bipy)(NO3)2Sc(µ-OH)2Sc(NO3)2 (bipy)] obtained by the reaction of hydrated scandium nitrate with 2,2′-bipyridyl (bipy) in either ethanol or nitromethane. The crystal structure of the complex shows that the scandium centers are eight coordinate, and the structure obtained contrasts with related complexes found in the lanthanide series [Ln(bipy)2 (NO3)3 ] and [Ln(phen)2 (NO3)3 ] (phen = phenanthroline) and in [M(terpy)(NO3)3 ] (M = Sc, Er–Lu), where these complexes are all mononuclear.

Data deposited in the Cambridge Structural Database (CSD) for compounds of scandium, yttrium, lanthanum and lutetium(III) have been analysed to assess the structural similarities of complexes of the different metal ions. 29 sets of compounds of Sc, Y, La and Lu where at least three of the elements form compounds with the same ligands have been identified and their crystal structures analysed. In 14 of them, scandium and lutetium have the same coordination number; in the remaining 15 they do not. Similarly, there are 10 examples where there is a difference in coordination number between Lu and Y for compounds with the same ligands. For the other 19 either the coordination numbers are the same or that compounds for both the elements under consideration have not been reported. Overall structural differences correlate well with the size of the metal ions and provide no true chemical basis for arranging Lu rather than La in one triad with Sc and Y.

This paper demonstrates the potential of vapochromic crystals as a sensing medium for measurements of local species concentration. Vapochromic crystals exhibit a reversible colour change based on the adsorption and desorption of water. As the water content of the crystals changes so too does the wavelength of light that they reflect (i.e. they change colour). In the situation where humid air mixes with a dry gas, the resulting specific humidity of the mixture can be related to the concentration level of the dry gas through a simple mass balance. As far as the authors are aware, this is the first time that vapochromic crystals have been used in this context. A number of the factors that affect the colour change of the crystal are investigated through simple flat plate experiments in a small wind tunnel. In all experiments, the hue and intensity of the vapochromic crystal was measured as a function of local dry gas concentration; in this case CO2. Green intensity levels exhibited the broadest activity over the widest range of CO2 levels, and was therefore used to quantify concentration. The crystals demonstrated a pronounced hysteresis, where the adsorption and desorption of water into the crystal structure was shown to occur at different concentration levels. The transition band was also shown to be highly temperature dependent when tested over a range of 22–44 °C. The vapochromic crystals were assessed for repeatability and found to sense the local CO2 concentration to ±1.5% CO2 over a range of green intensity values from 90 to 170. A practical example is presented to show how vapochromic crystals could be applied to the mixing of fluid streams in gas turbine film cooling.

Heteroaryl incorporated acetylide-functionalized pyridinyl ligands (L1-L6) with the general formula Py-C≡C-Ar (Py = pyridine and Ar = thiophene-2-yl, 2,2' -bithiophene]-5-yl, 2,2' :5',2″ -terthiophene]-5-yl, thieno[2,3- b]thiophen-2-yl, quinoline-5-yl, benzo[c][1,2,5]thiadiazole-5-yl) have been synthesized by Pd(0)/Cu(I)-catalyzed cross-coupling reaction of 4-ethynylpyridine and the respective heteroaryl halide. Ligands L1-L6 were isolated in respectable yields and characterized by microanalysis, IR spectroscopy, 1H NMR spectroscopy, and ESI-MS mass spectrometry. A series of dinuclear Cu(I) complexes 1-10 have been synthesized by reacting L1-L6 with CuI and triphenylphosphine (PPh3) (R1) or with an anchored phosphine derivative, 4-(diphenylphosphino) benzoic acid (R2)/2-(diphenylphosphino)benzenesulfonic acid (R3), in a stoichiometric ratio. The complexes are soluble in common organic solvents and have been characterized by analytical, spectroscopic, and computational methods. Single-crystal X-ray structure analysis confirmed rhomboid dimeric structures for complexes 1, 2, 4, and 5, and a polymeric structure for 6. Complexes 1-6 showed oxidation potential responses close to 0.9 V vs Fc0/+, which were chemically irreversible and are likely to be associated with multiple steps and core oxidation. Preliminary photovoltaic (PV) results of these new materials indicated moderate power conversion efficiency (PCE) in the range of 0.15-1.56% in dye-sensitized solar cells (DSSCs). The highest PCE was achieved with complex 10 bearing the sulfonic acid anchoring functionality.

An unusual heterobimetallic bis(triphenylphosphane)(NO2)AgI–CoIII(dimethylglyoximate)(NO2) coordination compound with both bridging and terminal –NO2 (nitro) coordination modes has been isolated and characterized from the reaction of [CoCl(DMGH)2(PPh3)] (DMGH2 is dimethylglyoxime or N,N′-dihydroxybutane-2,3-diimine) with excess AgNO2. In the title compound, namely bis(dimethylglyoximato-1κ2 O,O′)(μ-nitro-1κN:2κ2 O,O′)(nitro-1κN)bis(triphenylphosphane-2κP)cobalt(III)silver(I), [AgCo(C4H7N2O2)2(NO2)2(C18H15P)2], one of the ambidentate –NO2 ligands, in a bridging mode, chelates the AgI atom in an isobidentate κ2 O,O′-manner and its N atom is coordinated to the CoIII atom. The other –NO2 ligand is terminally κN-coordinated to the CoIII atom. The structure has been fully characterized by X-ray crystallography and spectroscopic methods. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been used to study the ground-state electronic structure and elucidate the origin of the electronic transitions, respectively.

We report two hitherto unknown polymorphs of the charge transfer (CT) cocrystal perylene:tetracyanoquinodimethane (TCNQ) grown by physical vapor transport (PVT) in argon atmosphere. One of the polymorphs, named β, has stoichiometry 1:1 and adds to the three known structures with stoichiometry 1:1 (α), 2:1, and 3:1. Interestingly, below (280 ± 10) K the β structure undergoes a phase transition to what we refer to as the γ polymorph, with halving of the unit cell and reduction of symmetry from monoclinic to triclinic. Both new crystal structures present two alternating stacks with different intermolecular and intramolecular geometries. In stack S–I the perylene molecules show substantial deviations from planarity, with the angle between the naphthalene intramolecular moieties of 6.69°, and with the perylene and TCNQ molecular centroids shifted by 1.95 Å. In the second stack, S-II, the perylene is planar, and the centroids almost coincident. Structural investigations on bond length complemented by vibrational IR spectroscopy indicate that in the new polymorphs the degree of charge transfer, ρ, can be 0 or 0.12. The higher value of ionicity to be due to donor–acceptor pairs in the S-II, while molecules in S-I are closer to neutrality. Thus, the ionicity of the donor–acceptor pair depends on the stack and is comparable to that of the α polymorph which we redetermined as ρ = 0.15 ± 0.05.

Presently it is understood that 18-crown-6 ether is necessary as an organic template to synthesise pure and well crystalline EMT-type zeolites. This is problematic for optimisation of organic-free synthesis of zeolites. We report a new method to synthesise pure zeolite EMC-2 using a lower amount of 18-crown-6 ether than previously reported. At these low 18-crown-6 ether concentrations, FAU-type zeolites were not seen to co-crystallise. We observe that the crystallinity of the EMT-type zeolite is proportional to the amount of 18-crown-6 ether added in the synthesis. The as-synthesised zeolites were characterised using X-ray powder diffraction, scanning electron microscopy and solid state nuclear magnetic resonance. These findings are a crucial step towards understanding template roles and designing syntheses for zeolites without the use of toxic organic templates.

Reaction of the electron-rich complex cis-[Pt(p-Me-C6H4)2(SMe2)2] with 2,2′-bipyridine N-oxide, O-bpy occurred by rollover cyclometalation to afford complex [Pt(O-bpy)(p-Me-C6H4)(SMe2)], 1. The obtained complex was characterized using NMR spectroscopy and its solid state structure was determined by the single crystal X-ray diffraction method. The reaction of 1 with seven diphosphine ligands, 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), N,N-bis(diphenylphosphino)amine (dppa), 1,2-bis(diphenylphosphino)benzene (dppbz) and 1,1′-bis(diphenylphosphino)ferrocene (dppf), in different molar ratios (1:1 or 1:0.5; 1:diphosphines) was studied. In accordance with the reaction conditions, the analogous mononuclear or binuclear diphosphine cycloplatinated complexes were yielded. The diphosphines behave as a monodentate (dppm and dppa), a bridging (dppm, dppa, dppe, dppp, dppb and dppf) or a chelated (dppe, dppp and dppbz) ligand. These behaviors depend on the bite angle of the diphosphine ligands, and the flexibility or rigidity of the alkyl and aromatic backbone between the two phosphine groups. All diphosphine platinum complexes were characterized using NMR spectroscopy and the crystal structures of some complexes were solved by X-ray diffraction.

[Ru3(CO)12] reacts at room temperature with N-alkyl substituted 6-membered ring N-heterocyclic carbenes (6-NHC) to form [Ru3(6-NHC)(CO)10] (6-NHC = 6-iPr 1, 6-Et 2 and 6-Me 4), rare examples of coordinatively unsaturated (46-electron) ruthenium clusters. Complexes 1, 2 and 4 have been structurally characterised, along with the tetranuclear ruthenium cluster [Ru4(6-Et)2(CO)11] 3 that is formed along with 2. The degradation of the 6-iPr derivative 1 by pyrimidinium salt elimination helped to explain the poor activity of the complex in the catalytic acylation of pyridine.

A new diaza-macrocyclic ligand bearing two pyridine side arms (L2) was synthesized and characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, FT-IR, and 1H and 13C NMR methods. The macrocyclic ligand showed a great tendency to act as an appropriate tecton in the formation of coordination polymers in the presence of Cu, Ni, Mn, Pb, and Cd chlorides. Five new isostructural one dimensional metal–organic coordination polymers [{M(Cl)2}(L)4] (M = Cu, Ni, Mn, Pb, Cd) were prepared in DMSO or DMF and characterized by elemental analysis, IR spectroscopy, TGA-DTG, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. All of the polymers were employed as solid sorbents for Cr(VI) anions in aqueous solution. Within the series, the Pb(II) coordination polymer demonstrated notable absorption behavior for sorption of Cr(VI) and some oxo-anions such as MoO42−, WO42−, and MnO4− (environmental concern anions), together with HPO42−. The anion adsorption properties were attributed to the presence of surface positive charge on the coordination polymer.

A new tris β-diketonate europium(III) complex [Eu(btfa)3Py-Im] (Eu-1) (4,4,4-trifluoro-1-phenyl-1,3-butanedione (btfa) and 2-(2-pyridyl)benzimidazole (Py-Im)] has been synthesized and structurally characterized. A single crystal X-ray diffraction analysis shows that Eu-1 is octacoordinated and the coordination sphere is composed of a EuO6N2 core with a trigonal dodecahedral (D2d) geometry. The photophysical properties of Eu-1 were analysed in detail and with the help of the experimental PL data and theoretical modelling, energy transfer rates were calculated, and an energy transfer mechanism is proposed for Eu-1. The complex has been used as the emitting layer (EML) to fabricate organic light emitting diodes (OLEDs). Eight OLEDs, of which four single-EML and four double-EML with varying doping concentration, were fabricated via a thermal evaporation method using Eu-1 as the EML. Under the optimum conditions a highly monochromatic bright red emission (CIEx,y = 0.640, 0.311) with brightness (B) = 896 cd/m2, current efficiency (ηc) = 2.26 cd/A, power efficiency (ηp) = 1.92 lm/W and external quantum efficiency (EQE) = 1.6% at very low Vturn-on = 3.4 V was obtained.

A ligand field molecular mechanics (LFMM) force field has been constructed for the spin states of [Fe(bpp)2 ]2+ (bpp=2,6-di(pyrazol-1-yl)pyridine) and related complexes. A new charge scheme is employed which interpolates between partial charges for neutral bpp and protonated [H3 bpp]3+ to achieve a target metal charge. The LFMM angular overlap model (AOM) parameters are fitted to fully ab initio d orbital energies. However, several AOM parameter sets are possible. The ambiguity is resolved by calculating the Jahn-Teller distortion mode for high spin, which indicates that in [Fe(bpp)2 ]2+ pyridine is a π-acceptor and pyrazole a weak π-donor. The alternative fit, assumed previously, where both ligands act as π-donors leads to an inconsistent distortion. LFMM optimisations in the presence of [BF4 ]- or [PF6 ]- anions are in good agreement with experiment and the model also correctly predicts the spin state energetics for 3-pyrazolyl substituents where the interactions are mainly steric. However, for 4-pyridyl or 4-pyrazolyl substituents, LFMM only treats the electrostatic contribution which, for the pyridyl substituents, generates a fair correlation with the spin crossover transition temperatures, T1/2 , but in the reverse sense to the dominant electronic effect. Thus, LFMM generates its smallest spin state energy difference for the substituent with the highest T1/2 . One parameter set for all substituted bpp ligands is insufficient and further LFMM development will be required.

Tetra-coordinated copper(II) complexes, [CuL2] and [Cu(phox)2], were synthesized by reaction of 1-((4-bromophenylimino)methyl)naphthalen-2-ol, HL, and 2-(2′-hydroxyphenyl)-2-oxazoline, Hphox, ligands with copper acetate, respectively. The complexes were characterized using FT-IR spectroscopy, elemental analyses, and their solid state structures were confirmed by single crystal X-ray diffraction. The catalytic activity of the complexes was evaluated in one-pot azide–alkyne cycloaddition (AAC) click reaction in water without need of any additional agent. The [CuL2] complex showed high catalytic activity in this reaction‌‌‌ and 1,2,3-triazole derivatives were produced in moderate to good yields.

Herein, we describe for the first time synthesis, characterization, chemosenor behavior, and mechanism of metal ion-ligand interaction of two novel side-armed naphthodiaza-crown macrocycles (L1 and L2) by employing of IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy, CHN microanalysis and single crystal X-ray diffraction. Preliminary fluorescence studies in ethanol as solvent revealed that the metal ion recognition by L1 was strongly different from L2 suggesting the importance of the number of benzylic side-arms on the extent of the interaction with Mn+. For instance employing fluorescence titration in ethanol showed binding constant values 105 M−1 and 2.6×106 M−1 for L1/Al3+ and L2/Al3+, respectively. Such metal ion selectivity by L2, however, was sharply improved in aqueous media (1:1 v/v ethanol/water) in comparison with L1. The selective complex formation of L2 with Al3+ supported very low limit of detections, i.e. 5×10−7 and 7×10−6 M in ethanol and aqueous medium, respectively. Single crystal X-ray diffraction analysis (in solid) as well as 1H NMR spectroscopy in acidic DMSO-d6 solvent revealed that unparalleled direction of the electron lone pairs on the donor atoms of L2 could not let Al3+ cation to be coordinated simultaneously by both nitrogen-donor groups on the macrocycle ring. The coordination of Al3+ with both of those nitrogen donors on L2, however, was evident from the 1H NMR spectra of L2/Al3+ where the solvent was DMSO-d6.

Four novel ON donor Schiff bases (E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol (HL1),(E)-3-((4-(4-biphenyloxy)phenyliminomethyl)benzene-1,2-diol (HL2), (E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol (HL3), (E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol (HL4) and their copper(II) complexes bis((E)-3-((4-phenoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L1)2) bis((E)-3-((4-(4-biphenyloxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L2)2), bis((E)-3-((4-naphthoxyphenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L3)2), bis((E)-3-((4-(2-naphthoxy)phenylimino)methyl)benzene-1,2-diol) copper(II) (Cu(L4)2) have been synthesized and characterized by spectroscopic (FTIR, NMR, UV–visible) and elemental analysis. The crystal structures of HL1, HL2, HL3, and HL4 have been determined, which reveal intramolecular N-H⋯O (HL1, HL2, HL3, and HL4) hydrogen bonds in the solid state. Keto-amine and enol-imine tautomerism is exhibited by the Schiff bases in solid and solution states. The Schiff bases and their copper(II) complexes have been screened for their biological activities. In antimicrobial assays (antibacterial and antifungal), HL4 showed promising results against all strains through dual inhibition property while the rest of the compounds showed activity against selective strains. On the other hand, in cytotoxic, DPPH, and inhibition of hydroxyl (OH) free radical-induced DNA damage assays, the results were found significantly correlated with each other, i.e. the ligands HL1 and HL2 showed moderate activity while their complexes Cu(L1)2 and Cu(L2)2 exhibited prominent increase in activity. As the results of these assays are supporting each other, it represents the strong positive correlation and antioxidant nature of investigated compounds.

Square planar platinum(ii) complexes have been known for 150 years and pincer complexes, supported by a tridentate chelating ligand such as terpyridyl, have been known for more than 70 years. The development of cyclometallated platinum(ii) pincer complexes, in which the tridentate ligand forms one or more platinum-carbon bonds, has been much more recent. Particularly, in terms of their solution and solid-state luminescence these cyclometallated complexes show substantial advantages over their terpyridyl analogues. This tutorial review introduces the reader to the area of platinum(ii) cyclometallated pincer chemistry and shows the advantage of having an alkynyl group in the fourth coordination site on the metal. The basic design principles for the preparation of highly luminescent platinum(ii) cyclometallated pincer complexes are outlined and the strategy to improve the luminescence further by chemical manipulation of the pincer ligand and of the auxiliary ligand in the fourth coordination site are illustrated with recent examples from the literature. Recent applications of these cyclometallated pincer complexes in the area of opto-electronics is described, with emphasis on their use in OLEDs, OFETs and as NLO materials as well as demonstrating their potential use as triplet photosensitizers and as metal ion sensors. The aim of this review is to show the recent advances in this rapidly developing research field and to highlight the future promise of these materials.

Presently there is little clarity concerning how organic additives control structure formation in the synthesis of zeolite catalysts and their chemistry. Such ambiguity is a major obstacle towards the synthesis design for new bespoke zeolites with intended applications. Herein, we have applied inelastic neutron scattering (INS) spectroscopy to experimentally probe the organic-framework interactions that are crucial to the structure direction process. With this technique we have studied the dynamics of 18-crown-6 ether, which can be used as an additive to direct the formation of four zeolites: Na-X, EMC-2, RHO and ZK-5. We observe significant softening of the 18-crown-6 ether molecule’s dynamics upon occlusion within a zeolite host, with a strong influence on both the circular and radial vibrational modes. Furthermore, there is a strong correlation between the efficacy of the organic additive and the strength of the organic-framework interactions, which are a consequence of both the framework cavity size and geometry. We propose that the approach used herein should be used to study other zeolites, and hence gain a more comprehensive view of structure directing organic-framework interactions.

Two new lanthanide complexes [Ln(hfaa)3(Py-Im)] [hfaa = hexafluoroacetylacetone, Py-Im = 2-(2-pyridyl)benzimidazole and Ln = Eu(III) (1) and Tb(III) (2)] were synthesized and characterized. An X-ra...

Previous work has shown a strong correlation between zeolite framework flexibility and the nature of structural symmetry and phase transitions. However, there is little experimental data regarding this relationship, in addition to how flexibility can be connected to the synthesis of these open-framework materials. This is of interest for the synthesis of novel zeolites, which require organic additives to permutate the resulting geometry and symmetry of the framework. Here, we have used high-pressure powder X-ray diffraction to study the three zeolites: Na-X, RHO and ZK-5, which can all be prepared using 18-crown-6 ether as an organic additive. We observe significant differences in how the occluded 18-crown-6 ether influences the framework flexibility—this being dependent on the geometry of the framework. We use these differences as an indicator to define the role of 18-crown-6 ether during zeolite crystallization. Furthermore, in conjunction with previous work, we predict that pressure-induced symmetry transitions are intrinsic to body-centred cubic zeolites. The high symmetry yields fewer degrees of freedom, meaning it is energetically favourable to lower the symmetry to facilitate further compression.

Three tetra-ferrocenylethynylpyridinyl copper complexes, L 4 (CuI) 4 ( 1 ), L 4 (CuBr) 2 ( 2 ), L 4 (CuCl) 2 ( 3 ) and one ferrocenylethynylpyridinyl Ligand ( L) have been investigated for their HOMO and LUMO energy levels. The band gap energy for each material has been calculated using optical absorption spectrum. Cyclic Voltammetry was used to estimate the oxidation potential and energy band diagram consequently. Cyclic voltammetry in dichloroethane showed chemically reversible multiferrocenyl oxidation signals with evidence for product electro-crystallization. We isolated the semi-oxidized products by electrodeposition onto a Pt disc electrode and investigated by scanning electron microscopy (SEM). SEM confirmed the spontaneous formation of crystalline oxidation products with distinctive morphologies for complex 1 & 3 . Energy dispersive X-ray elemental analysis shows presence of hexaflurophosphate (counter-ion) with the Fe:P ratio of 2:1, and 2:1 for the electrocrystallized products of 1 and 3 , respectively proposing the formulae [ 1 ] 2+ (PF 6 − ) 4 and [ 3 ] 2+ (PF 6 − ) 2 for the electro-crystallized products.

Single-crystal crystallography shows that one polytype of the AuI trimer tris(μ2-3,5-diiso­propyl-1,2,4-triazolato-κ2 N 1:N 2)trigold(I), [Au3(N3C8H14)3], undergoes four successive phase transitions between 1 and 3.5 GPa, driven by aurophilic interactions, and that the ambient-pressure structure re-emerges at high pressure., We report a molecular crystal that exhibits four successive phase transitions under hydro­static pressure, driven by aurophilic interactions, with the ground-state structure re-emerging at high pressure. The effect of pressure on two polytypes of tris(μ2-3,5-diiso­propyl-1,2,4-triazolato-κ2 N 1:N 2)trigold(I) (denoted Form-I and Form-II) has been analysed using luminescence spectroscopy, single-crystal X-ray diffraction and first-principles computation. A unique phase behaviour was observed in Form-I, with a complex sequence of phase transitions between 1 and 3.5 GPa. The ambient C2/c mother cell transforms to a P21/n phase above 1 GPa, followed by a P21/a phase above 2 GPa and a large-volume C2/c supercell at 2.70 GPa, with the previously observed P21/n phase then reappearing at higher pressure. The observation of crystallographically identical low- and high-pressure P21/n phases makes this a rare example of a re-entrant phase transformation. The phase behaviour has been characterized using detailed crystallographic theory and modelling, and rationalized in terms of molecular structural distortions. The dramatic changes in conformation are correlated with shifts of the luminescence maxima, from a band maximum at 14040 cm−1 at 2.40 GPa, decreasing steeply to 13550 cm−1 at 3 GPa. A similar study of Form-II displays more conventional crystallographic behaviour, indicating that the complex behaviour observed in Form-I is likely to be a direct consequence of the differences in crystal packing between the two polytypes.

Solar cells (SCs) are of considerable current research interest because of their potential as a clean alternative to fossil fuels. Researchers across the globe are developing novel polymeric materials with enhanced power conversion efficiency (PCE). Conjugated poly-ynes and poly(metalla-ynes) incorporating late transition metals and thiophene-based spacers have played a very important role in this strategic area of materials research. The performance of the SCs can be optimized by varying the conjugated spacers and/or the metal ions along the polymer backbone. Therefore, an analysis of structure-photovoltaic property relationships in poly-ynes and poly(metalla-ynes) is desirable as a guide for the development of new functional materials for use in SCs. Keeping the importance of this strategic topic in mind, herein we present a brief review on conjugated poly-ynes and poly(metalla-ynes) incorporating thiophene-based spacers that have potential SC applications. Attempts have been made to correlate the photovoltaic performance of the SCs to the chemical structure of thiophene-incorporated poly-ynes and poly(metalla-ynes). The performance of SCs is also strongly influenced by other factors such as morphology and device structure.

Nine hydrogen bonded networks of N-phenylurea and 5-nitroisophthalic acid, with solvent inclusion properties, have been engineered and their thermal stabilities studied. Solvent guests of methanol, ethanol, acetonitrile, acetone, THF, ethyl acetate and water have been included into the hydrogen bonded host networks in pockets and channels via interaction with a carboxylic acid group of the host. Two non-solvated N-phenylurea 5-nitroisophthalic acid complexes (NS1 2:1 and NS2 1:1) were also formed. Thermal studies of the inclusion materials revealed guest release and conversion to NS1, in all but one case, and conversion of one non-solvated form to the other (NS2 to NS1). The carboxylic acid:amide hydrogen bond synthon R22(8) was shown to be a robust synthon for network formation whilst guest molecules are suggested to have a role in templating the overall network geometry.

Jack Lewis was born and educated in Lancashire. He rose rapidly to become a highly renowned chemist who helped to pioneer the development of modern inorganic chemistry. He was one of the small group of scientists who led the expansion of inorganic chemistry from its renaissance, inspired by Professor Ron Nyholm in the mid 1950s, through the syntheses and study of new transition-metal and organometallic complexes. Their characterization was accomplished through the perceptive application of the newly available physical techniques of spectroscopy (electronic, vibrational and nuclear magnetic resonance), magnetism, mass spectrometry and X-ray diffraction. Jack completed his PhD at the University of Nottingham in 1952, and then held academic appointments in close succession at the University of Sheffield, Imperial College, London, and University College London (UCL) before being appointed Professor of Chemistry at the University of Manchester in early 1962. He returned to UCL as Professor of Chemistry for the period 1967–70 before being appointed the 1970 Professor of Chemistry at the University of Cambridge, a position that he held until 1995, when he was granted emeritus status. His dedication to the study and furtherance of inorganic chemistry was profound and his research achievements were made all the more remarkable when one considers his substantial additional high-profile responsibilities. In 1975 Jack became the first Warden of the newly established Robinson College in Cambridge, where he shaped and guided a progressive academic community until his retirement in 2001. Furthermore, his skill as a highly effective debater also took him, in 1989, to the House of Lords, where as a Life Peer he represented science with great enthusiasm and distinction until a few months before his death. He was a most effective chairman of the Royal Commission on Environmental Pollution from 1985 to 1992.

Every year millions of tons of zeolites are produced, being used as molecular sieves, hydrocracking catalysts, gas-capture materials and for emerging novel applications. There is a demand to synthesise new zeolites with bespoke frameworks, which are tailor-made for a chosen application. To achieve these ‘designer zeolites’ it is crucial to fully understand the host-guest interactions between organic additives and zeolitic frameworks. Here we have studied four different zeolites, synthesised with the same organic additive, 18-crown-6 ether, which show observable differences in the host-guest interactions. We demonstrate that the framework geometry dominates the decomposition temperature, enthalpy and mechanism. The zeolites show unique decomposition features, emphasising experimental differences in how the organic additive and framework interact.

A targeted new dioxo molybdenum(VI) ONO Schiff base complex was prepared for catalyzing epoxidation of olefins in water. This complex was characterized by FT-IR, NMR, UV–Vis, and X-ray crystallography techniques. DFT calculations are additionally performed to find ground and transition states for finding electronic structure and UV–Vis assignment. Afterward, a new protocol was defined for sustainable catalytic epoxidation of olefin in water using this complex as a green catalyst, and also remarkable results are obtained, such as turn over number up to 1400.

Previous work has shown a strong correlation between zeolite framework flexibility and the nature of structural symmetry and phase transitions. However, there is little experimental data regarding this relationship, in addition to how flexibility can be connected to the synthesis of these open framework materials. This is of interest for the synthesis of novel zeolites, which require organic additives to permutate the resulting geometry and symmetry of the framework. Here, we have used high pressure powder X-ray diffraction to study the three zeolites: Na-X, RHO and ZK-5, which can all be prepared using 18-crown-6 ether as an organic additive. We observe significant differences in how the occluded 18-crown-6 ether influences the framework flexibility – this being dependant on the geometry of the framework. We use these differences as an indicator to define the role of 18-crown-6 ether during zeolite crystallisation. Furthermore, in conjunction with previous work we predict that pressure-induced symmetry transitions are intrinsic to body-centred cubic zeolites. The high symmetry yields fewer degrees of freedom, meaning it is energetically favourable to lower the symmetry to facilitate further compression.

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

An unusual heterobimetallic bis(triphenylphosphane)(NO

A family of tin(ii) guanidinate complexes of the general form [{RNC(NMe2)NR}2Sn] (R = iPr (6), Cy (7), Tol (9) and Dipp (10)) and [{tBuNC(NMe2)NtBu}Sn{NMe2}] (8) have been synthesised and isolated from the reaction of tin(ii) bis-dimethylamide and a series of carbodiimides (1-5). The cyclic poly-chalcogenide compounds [{CyNC(NMe2)NCy}2Sn{Chx}] (Ch = S, x = 4 (11); Ch = Se, x = 4 (12), and Ch = S, x = 6 (13)) with {SnChx} rings were prepared by the oxidative addition of elemental sulfur and selenium to the heteroleptic stannylene complex [{CyNC(NMe2)NCy}2Sn] (7) in THF at room temperature. Similarly, reaction of compounds 6 and 7 with an equimolar amount of the chalcogen transfer reagents (SC3H6 and Se[double bond, length as m-dash]PEt3, respectively) led to the formation of the chalcogenide tin(iv) complexes [{RNC(NMe2)NR}Sn(Ch)] (R = Cy: Ch = S (14); R = iPr, Ch = Se (15); R = Cy, Ch = Se (16)) with terminal Sn[double bond, length as m-dash]Ch (14 and 16) and dimeric bridged seleno-tin {Sn2Se2} rings (15), respectively. The mono telluro-compounds [{RNC(NMe2)NR}Sn(Te)] (R = iPr (17); R = Cy (18)) were similarly prepared by the oxidative addition of elemental tellurium to 7 and 8, respectively. All of the tin containing compounds have been investigated by multinuclear NMR (1H, 13C 119Sn and 77Se/125Te, where possible), elemental analysis and single crystal X-ray structural analysis (7, 8, 10-13, 15-18). Thermogravimetric analysis (TGA) was used to probe the possible utility of complexes 6-8, 11-12 and 14-18 as single source Sn and SnCh precursors. The Sn(ii) compounds 6 and 7 have been utilised in the growth of thin films by aerosol-assisted chemical vapor deposition (AACVD) at both 300 and 400 °C. The thin films have been analysed by pXRD, EDS, SEM and AFM and shown to be Sn metal. Subsequent studies provided film growth at temperatures as low as 200 °C. Similarly, the mono-chalcogenide systems 14, 16 and 18 have been utilised in the AACVD of thin films. These latter studies provided films, grown at 300 and 400 °C, which have also been analysed by pXRD, Raman spectroscopy, AFM, and SEM and are shown to comprise phase pure SnS, SnSe and SnTe, respectively. These preliminary results demonstrate the potential of such simple guanidinate complexes to act as single source precursors with a high degree of oxidative control over the deposited thin films.

The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc‐NH2)6] (UiO‐66‐NH2, bdc‐NH2=2‐amino‐1,4‐benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2‐mercaptoimidazole led to post‐synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2‐mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO‐66‐NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol‐containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc‐NH2)3] (IRMOF‐3), but a similar reaction on [Zn2(bdc‐NH2)2(dabco)] (dabco=1,4‐diazabicyclo[2.2.2]octane) gave [Zn3(bdc‐NH2)1.32(bdc‐NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc‐NH2)] (MIL‐68(In)‐NH2) stop after the first step, and the product was identified as [In(OH)(bdc‐NH2)0.41(bdc‐NHCH2OCH3)0.30(bdc‐N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.