Reaction Of Bis Research Articles

Synthesis, Biophysical Interaction of DNA/BSA, Equilibrium and Stopped-Flow Kinetic Studies, and Biological Evaluation of bis(2-Picolyl)amine-Based Nickel(II) Complex.

Reaction of bis(2-picolyl)amine (BPA) with Ni(II) salt yielded [(BPA)NiCl2(H2O)] (NiBPA). The Ni(II) in NiBPA bound to a BPA ligand, two chloride, and one aqua ligands. Because most medications inhibit biological processes by binding to a specific protein, the stopped-flow technique was used to investigate DNA/protein binding in-vitro, and a mechanism was proposed. NiBPA binds to DNA/protein more strongly than BPA via a static quenching mechanism. Using the stopped-flow technique, a mechanism was proposed. BSA interacts with BPA via a fast reversible step followed by a slow irreversible step, whereas NiBPA interacts via two reversible steps. DNA, on the other hand, binds to BPA and NiBPA via the same mechanism through two reversible steps. Although BSA interacts with NiBPA much faster, NiBPA has a much higher affinity for DNA (2077 M) than BSA (30.3 M). Compared to NiBPA, BPA was found to form a more stable BSA complex. When BPA and NiBPA bind to DNA, the Ni(II) center was found to influence the rate but not the mechanism, whereas, for BSA, the Ni(II) center was found to change both the mechanism and the rate. Additionally, NiBPA exhibited significant cytotoxicity and antibacterial activity, which is consistent with the binding constants but not the kinetic stability. This shows that in our situation, biological activity is significantly more influenced by binding constants than by kinetic stability. Due to its selectivity and cytotoxic activity, complex NiBPA is anticipated to be used in medicine.

Neutron spectroscopy: The case of the spherical proportional counter

Neutron spectroscopy is an invaluable tool for many scientific and industrial applications, including underground Dark Matter searches. Neutron-induced backgrounds produced by cosmic ray muons and the cavern radioactivity can mimic the expected Dark Matter signal. However, existing neutron detection methods have several drawbacks and limitations, thus measurements remain elusive. A promising new approach to neutron spectroscopy is the use of a nitrogen-filled spherical proportional counter that exploits the 14N(n,α)11B and 14N(n,p)14C reactions. This is a safe, inexpensive, effective and reliable technique. In this work, the latest instrumentation developments are incorporated in a compact detector operated at the University of Birmingham (UoB) with high gain at gas pressure up to 1.8bar. We demonstrate spectroscopic measurements of thermalised and fast neutrons respectively from an 241Am-9Be source and from the MC40 cyclotron facility at UoB. Additionally, the detector response to neutrons is simulated using a framework developed at UoB and compared with the experimental results.

SYNTHESIS, SPECTRAL CHARACTERIZATION AND ANTIMICROBIAL STUDIES OF BIS(CYCLOPENTADIENYL)- ZIRCONIUM(IV) DERIVATIVES WITH QUINAZOLINONE SCHIFF BASES

Zirconium(IV) complexes of types [(C5H5)2Zr(L)] and [(C5H5)Zr(LÂ’)Cl] (LH2 represents Schiff bases derived from quinazolinone and salycylaldehye or o-hydroxyacetophenone LÂ’H represents Schiff bases derived from quinazolinone and 4-fluorobenzaldehyde/ 4-fluoro acetophenone /1-(2-fluoro-4-methylphenyl)-2-methylpropan-1-one / 1-(2-fluoro-4-methylphenyl) propan-1-one ) have been synthesized by the reactions of bis(cyclopentadienyl)zirconium(IV) dichloride with appropriate ligands in tetrahydrofuran in the presence of triethylamine. All these complexes are soluble in THF, PhNO2, DMF and DMSO. The complexes were characterized by elemental analyses, electrical conductance, magnetic susceptibility, IR, 1H NMR, XRD and SEM spectral techniques. Low molar conductance values indicate non-electrolytic nature of the complexes. The spectral data indicate 5-coordinate geometry for the complexes. XRD pattern evince that the complexes have monoclinic crystal system and particle sizes were found in the range 46.40-49.30 nm (nano-size). In vitro antifungal activity of synthesized compounds was evaluated against fungi Aspergillus niger, Aspergillus fumigatus, Candida albicans and In vitro antibacterial activity was determined by screening the compounds against gram negative (P. aeruginosa, E.coli) and gram positive (S. aureus and B. subtilis) bacterial strains using minimum inhibition concentration method (MIC) by serial dilution technique. The zirconocene(IV) complexes have higher antimicrobial impact than the parent Schiff bases.

Design and Syntheses of Ruthenium ENE (E = S, Se) Pincer Complexes: A Versatile System for Catalytic and Biological Applications.

This report describes the synthesis of two ruthenium(II) ENE pincer complexes (E = S, C1 and E = Se, C2) by the reaction of bis(2-(phenylchalcogenyl)ethyl)amine (L1, L2) with RuCl2 (PPh3 )3 . The complexes were characterized with the help of 1 H and 13 C{1 H} NMR, FTIR, HRMS, cyclic voltammetry and elemental analysis techniques. The structure and bonding mode of ligand with ruthenium in C2 was established with the help of single crystal X-ray diffraction. The complex showed distorted octahedral geometry with two chlorine atoms trans to each other. The Ru-Se bond distances (Å) are 2.4564(3)-2.4630(3), Ru-N distance is 2.181(2), Ru-P distance is 2.2999(6), and Ru-Cl distances are 2.4078(6)-2.4314(6). The complexes showed good to excellent catalytic activity for the N-alkylation of o-phenylenediamine with benzyl alcohol derivatives to synthesize 1,2-disubstituted benzimidazole derivatives. The complexes were also found to be efficient for aerobic oxidation of benzyl alcohols to corresponding aldehydes which are precursors to the bisimines generated in situ during the synthesis of 1,2-disubstituted benzimidazole derivatives. Complex C2 where selenium is coordinated with ruthenium was found to be more efficient as compared to sulfur coordinated ruthenium complex C1. Since ruthenium complexes are getting increasing attention for developing new anticancer agents, the preliminary studies like binding behavior of both the complexes towards CT-DNA were studied by competitive binding with ethidium bromide (EthBr) using emission spectroscopy. In addition, the interactions of C1-C2 were also studied with bovine serum albumin (BSA) using steady state fluorescence quenching and synchronous fluorescence studies. A good stability of Ru(II) state was observed by cyclic voltammetric studies of C1-C2. Overall these molecules are good examples of bio-organometallic systems for catalytic and biological applications.

Resonant scattering measurement for 11C using thick target in inverse kinematics

The resonant scattering of 10B+p reaction was measured at θ c.m.= 180°, 170°, 160°, 150° and 140° using a 35.93 MeV 10B beam to investigate the spectroscopy of 11C with the thick target inverse kinematic method at RIBRAS facility, IFUSP, São Paulo. Influence of the stopping power uncertainty on the resonant scattering cross section values for 11C in the 10B(p, p)10B reaction is shown. The data measured for the reaction channels p(10B,α) and p(10B,3He) is also presented. Interestingly, the cross sections for the 3He channel are observed upto 2 MeV below the lowest energy measurement available in literature.

Investigation of relative stabilities of CPAM zirconium cycloalkylmethyl vs isomeric ω-alkenyl complexes: Crystal structures of the cyclobutylmethyl and cyclopentylmethyl complexes

Investigations of the syntheses, structural characterization, and relative stabilities of the cyclopentadienyl, amidinate Zr cycloalkylmethyl complexes, (CPAM)Zr(X)[CH2(cyclo-CmH2m-1)] (CPAM = (η5-C5Me5)[(N,N′)-κ2-N(Et)-C(Me)N(t-Bu)]) for X = Cl and m = 3 (1a), 4 (1b) and 5 (1c) and for X = Me, and m = 4 (2b), and of the corresponding isomeric ω-alkenyl complexes, (CPAM)Zr(Cl)[CH2(CH2)nCH2CH = CH2] for n = 0 (3a), 1 (3b) and 2 (3c), have been conducted. Hydrozirconation of methylenecyclopropane by (CPAM)Zr(X)Cl (X = H or D) (8), which is generated in situ through hydrogenolysis of the Zr-Si bond of (CPAM)Zr(SiMe2Ph)Cl (7), provided a high yield of 3a due to rapid isomerization of transiently generated 1a. In contrast, crystalline 1b could be isolated in high yield via hydrozirconation of methylenecyclobutane by 8, and it has been structurally characterized by X-ray crystallography. Thermolysis of 1b in solution provided a quantitative yield of 3b, while quantitative production of 1c was achieved through intramolecular cyclization of 3c by reversible chloride abstraction that was catalyzed by addition of the ion pair, {(CPAM)Zr(Me)}{B(C6F5)4} 10. The cyclobutylmethyl complex 2b was also prepared from 1b through traditional methylation using MeLi, and it too was structurally characterized by X-ray crystallography. In solution, 2b thermally decomposes at 25 °C to an intractable mixture. Finally, reaction of 2b with a stoichiometric amount of the borate B1 provided the corresponding ion pair complex, {(CPAM)Zr[CH2CH2CH2CH = CH2]}{B(C6F5)4} (9) in which the terminal alkenyl group is intramolecularly coordinated to the transition metal center as determined by 1H NMR spectroscopy. The results of a DFT (B3LYP / LANL2DZ (Zr) / 6-31G**) computational investigation for the 1b to 3b isomerization and for the structure of 9 are also included.

BORON-ENHANCED BIOLOGICAL EFFECTIVENESS OF PROTON IRRADIATION: STRATEGY TO ASSESS THE UNDERPINNING MECHANISM.

Proton radiotherapy for the treatment of cancer offers an excellent dose distribution. Cellular experiments have shown that in terms of biological effects, the sharp dose distribution is further amplified, by as much as 75%, in the presence of boron. It is a matter of debate whether the underlying physical processes involve the nuclear reaction of 11B with protons or 10B with secondary neutrons, both producing densely ionizing short-ranged particles. Likewise, potential roles of intercellular communication or boron acting as a radiosensitizer are not clear. We present an ongoing research project based on a multiscale approach to elucidate the mechanism by which boron enhances the effectiveness of proton irradiation in the Bragg peak. It combines experimental with simulation tools to study the physics of proton-boron interactions, and to analyze intra- and inter-cellular boron biology upon proton irradiation.

THE STUDIES OF THE EXCITATION FUNCTIONS OF REACTIONS WITH EMISSION OF γ - QUANTA INDUCED BY PROTONS WITH ENERGY 200…1800 keV ON NUCLEI OF 10B AND 11B

A systematic study of the relative thick-target yields of prompt γ-rays with the energies of the most suitable for elemental and isotopic analysis for stable boron isotopes following proton bombardment has been carried out at Ep = 200…1800 кeV. The relevant excitation function of γ-emission 429 keV from reaction 10B(p,αγ)7Be, 718 keV from reaction 10B(p,p'γ)10B, 4.439 and 16.106 MeV from reaction 11B(p,γ)12C are depicted and a tables of yields of prompt γ-rays as function of proton bombardment energy are given. The experimental procedure is described. Particular aspects of the measuring techniques are discussed.

Weakening the N-H Bonds of NH3 Ligands: Triple Hydrogen-Atom Abstraction to Form a Chromium(V) Nitride.

Weakening and cleaving N-H bonds is crucial for improving molecular ammonia (NH3) oxidation catalysts. We report the synthesis and H-atom-abstraction reaction of bis(ammonia)chromium porphyrin complexes Cr(TPP)(NH3)2 and Cr(TMP)(NH3)2 (TPP = 5,10,15,20-tetraphenyl-meso-porphyrin and TMP = 5,10,15,20-tetramesityl-meso-porphyrin) using bulky aryloxyl radicals. The triple H-atom-abstraction reaction results in the formation of CrV(por)(≡N), with the nitride derived from NH3, as indicated by UV-vis and IR and single-crystal structural determination of Cr(TPP)(≡N). Subsequent oxidation of this chromium(V) nitrido complex results in the formation of CrIII(por), with scission of the Cr≡N bond. Computational analysis illustrates the progression from CrII to CrV and evaluates the energetics of abstracting H atoms from CrII-NH3 to generate CrV≡N. The formation and isolation of CrV(por)(≡N) illustrates the stability of these species and the need to chemically activate the nitride ligand for atom transfer or N-N coupling reactivity.

Preparation and characterization of new types of sulfonated poly(ether sulfide sulfone) for application in fuel cell

ABSTRACT Sulfonated polysulfone membranes are among the best candidate for fuel cells. The main challenges are obtaining high conductivity and mechanical properties. Accordingly, disulfonated poly(ether sulfide sulfone) copolymer flexible films were prepared via reaction of bis(4-hydroxyphenyl) sulfide with sulfonated and non-sulfonated bis(4-fluorophenyl) sulfone, and subsequent solution casting. Thermal and mechanical properties, water uptake, oxidative stability, and ion exchange capacity were investigated. Proton conductivity of copolymers at 80°C was 0.131–0.198 S cm−1. Polymer with 45% degree of sulfonation showed optimized favorable properties. Copolymers indicated acceptable properties compared with Nafion that was partially related to the presence of flexible hydroxyphenyl sulfide moiety.

Collective acceleration of deuterons from the residual chamber atmosphere in a Luce diode

The collective acceleration of deuterons from the residual atmosphere of the Luce diode chamber is studied at a pressure of gaseous deuterium in the range of 0.029–0.177 Pa. The energy and number of accelerated deuterons were determined by neutron time-of-flight spectrometry and by measuring the activity of 13N and 11C radionuclides induced in B4C targets by the reactions 12C(d,n)13N and 10B(d,n)11C, the activity of the 7Be induced by the 10B(p,αγ)7Be reaction was used to control the number of accelerated protons. The neutron time-of-flight shows that the gaseous products of polyethylene anode erosion have no noticeable effect on the energy and number of deuterons accelerated in shots following the first shot of the series. It is shown that the energy of deuterons accelerated from the residual atmosphere is the same as during their acceleration from the near-anode plasma using a deuterated polyethylene anode, but the number of accelerated deuterons per shot depends on the deuterium pressure exponentially, still it is by an order of magnitude smaller even at a pressure of 0.177 Pa. The exponential growth is due to the fact that the number of accelerated deuterons strongly depends on the diode current, which increases noticeably with increasing the deuterium pressure.

Incensole derivatives from frankincense: Isolation, enhancement, synthetic modification, and a plausible mechanism of their anti-depression activity

Encouraged by the potent anti-depression activities of incensole (1) and incensole acetate (2) isolated from the resin of Boswellia papyrifera in our previous work, different derivatives of 1 and 2 were synthesized in the present study. The reaction of 1 with m-CPBA afforded the mono-epoxide derivative 3a, while the same reaction with 2 led to three different epoxide derivatives 3a, 3b, and 3c. Oxidation of 1 with PCC to get compound 3b, however along with the target 3b, the reaction gave three interesting side products (3c-3e). Oxime (3b-1) resulted from the reaction of 3b with hydroxylamine hydrochloride in pyridine, while epoxidation of 2 generate three epoxide products (4a-4c). The structures of all products were unambiguously confirmed using NMR and Mass spectrometry. Compounds 3a-e and 4a-c (0.1–3 mg/kg, i.p.) demonstrated promising anti-depression activities in classical mouse models of depression of FST and TST. The results showed that compounds 3a-e and 4a-c (0.1–3 mg/kg, i.p.) caused dose dependent reduction in immobility time compared to the vehicle control, with 3c-3e and 4b-4c demonstrating higher potency and efficacy. The findings of the open field test excluded the motor effects of these compounds, thus further confirming their anti-depression activity. Preliminary investigation into their mechanism of action using GABA antagonist, PTZ and molecular docking has predicted that compounds 3e and 4c bind at the GABA binding site of GABAA receptor to produce GABAergic effects. Furthermore, the promising anti-depression potency of compounds 1 and 2 and their derivatives make them lead compounds for drug discovery.

Synthesis and Sensor Properties of Silicon Phthalocyanine Axially Substituted with Bis-(Prop-2-Ynyloxy) Groups and Polymeric Phthalocyanines Bearing PEG Substituent by “Click” Chemistry

Synthesis and characterization of new axially substituted phthalocyanine complexes were done. Bis - (prop-2-ynyloxy) phthalocyaninato silicon (IV) compound was obtained from the reaction of 2-propin-1-ol with SiPcCl2. Polymeric phthalocyanine containing axially substituted PEG was obtained from the reaction of bis - (prop-2-ynyloxy) phthalocyaninato silicon (IV) compound and polyethylene glycol azido. The structure of the compounds was justified by FT-IR, 1H NMR, 13C NMR, UV–Vis, and mass spectra. The photophysical and photochemical properties of the phthalocyanine compound axially substituted with bis-(prop-2-ynyloxy) was investigated. Properties of the compounds were examined in terms of fluorescence quantum efficiency and singlet oxygen generating capacity, and the potential photosensitizer capacity of the compound was determined. In addition, polyethylene glycol group was added to the phthalocyanine compound by click reaction. The polymer product was obtained in blue color. Phthalocyanine(Pc) containing PEG polymeric units is soluble in dimethyl sulfoxide (DMSO). Absorption measurements of the compound at different concentrations were made. Both polyethylene glycol (PEG) and phthalocyanine compounds can be used in the manufacture of medical supplies due to their non-toxicity. UV–visible study of Bis-(prop-2-ynyloxy) phthalocyaninato silicon (IV) compound revealed its high selectivity for Fe3+ ion recognition.

Ambiguities from Nuclear Interactions in the \(^{12}\)C(p,2p)\(^{11}\)B Reaction

We investigate the impact of ambiguities coming from the choice of optical potentials and nucleon-nucleon scattering cross sections on the spectroscopic factors extracted from the 12C(p,2p)11B reaction. These ambiguities are evaluated by analyzing the cross sections of the 12C(p,2p)11B reaction at 100 and 200 MeV within the framework of the distorted-wave impulse approximation with realistic choices of nuclear inputs. The results show that the studied ambiguities are considerably large in this energy region and careful choices of nuclear inputs used in the reaction calculations are required to extract reliable structure information.

Gamma-ray measurements in D[formula omitted] fusion plasma experiments on JET

Using capabilities of the gamma-ray spectrometry, fusion born alpha-particles were studied in recent D-3He plasma experiments on JET. A substantial population of the alpha-particles was generated in the 3He-rich plasma due to the 3He(D, p)4He reaction. Fast deuterium ions of the neutral beam injection (NBI) heating were accelerated to MeV energies with three-ion scenario D-(DNBI)-3He using radio frequency waves in the ion cyclotron range of frequencies (ICRF). A high reaction rate allowed to measure the alpha-particle production rate and their spatial distribution in the plasma by detecting 16.7-MeV gamma-rays from the 3He(D, γ)5Li reaction, which is a weak branch of 3He(D, p)4He reaction. A branching ratio of gamma-ray transitions to the ground and the first excited states of 5Li was obtained. Due to the beryllium is a main impurity of JET plasmas, intensive gamma-rays from the 9Be(D, nγ)10B, 9Be(D, pγ)10Be and 9Be(α, nγ)12C reactions were observed. Exploitation of the reaction cross-sections and the Doppler shape analysis (DSA) of gamma-lines in the recorded spectra provided the possibility to reconstruct distribution functions of the confined D-ions and the fusion-born alpha-particles.

THE ASTROPHYSİCAL S FACTOR FOR THE 7Be(p,γ)8B REACTİON AT LOW ENERGİES

The astrophysical S factor was calculated by using the ANC within the modified R matrix method. The new resonance parameters for the radiative capture 7Be(p,γ)8B reaction were obtained. The astrophysical S factor was extrapolated to the low energies. The S-factor S17(0)=21.62±1.13 keV b was found.

Research on proton beam spot imaging based on pixelated gamma detector

The secondary particles from the spallation target of the China Spallation Neutron Source are mainly gammas and neutrons, which are related to the incident proton. The reconstruction of the proton beam spot could be implemented based on the distribution of the positions of secondary gammas or neutrons. The methods of pinhole imaging and Compton imaging are developed by measuring the position distribution of gammas based on the pixelated detector. The secondary gammas could be detected by the pixelated gamma detector directly. The neutron can be identified by detecting the characteristic (478 keV) γ-rays from the 10B(n, α) reactions. In order to detect secondary neutrons, a layer of 10B converter is added before the pixelated gamma detector. The pixelated gamma detector is sensitive to the characteristic (478 keV) γ-rays and then the neutron imaging could be achieved based on measuring the position distribution of the characteristic (478 keV) γ-rays.

Neutron time-of-flight spectrometry of high-energy proton bunches collectively accelerated in the Luce diode

In this work, we investigated the possibility of detecting high-energy proton bunches collectively accelerated in a Luce diode by combining selective time-of-flight spectrometry of neutrons from the threshold reaction 11B(p,n)11C and instantaneous γ-spectrometry based on reactions 10B(p, αγ)7Be, 12C(p, γ)13N, and 11B(p, γ)12C, excited in B4C targets. It is shown that with an increase in the voltage across the Luce diode from 262 ± 15 to 312 ± 12 kV, on average in a series of 10 shots, the number of protons with energies above 3.02 MeV increases by two orders of magnitude — up to 3 ⋅ 1010 per shot, which opens up the possibility of ToF spectrometry of above-threshold neutrons with an average energy of about 0.3 MeV. It is shown that high-energy protons bunches noticeably outstrip the main proton bunches with an energy of 2.5eUd (e — electron charge, Ud — voltage on the diode) and up to 6 ⋅ 1014 protons per shot. This indicates that the smallest portions of protons can be captured first in the collective acceleration, which, due to the smaller lag behind the ion mover, are in the process of acceleration for a longer time and, thus, are accelerated to the highest energies.

Synthesis, Characterization and Antioxidant Activity of Two Novel Oxovanadium (IV) Curcuminoids

The reaction of bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (curcumin) and two novel ligands of bis[4- tetrabenzylglucose-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (bis(tetrabenzylglucose)curcumin) (BTBGC) and bis[4-tetraacetylglucose- 3-methoxyphenyl]-1,6-heptadiene-3,5-dione (bis(tetraacetylglucose)curcumin) (BTAGC) with vanadium in methanol, in a 2:1 molar ratio, which yield the complexes of ML2 where M is [VO]2+, have been synthesized and characterized by FT-IR, mass spectrometry, 1H NMR spectroscopy and elemental analysis. These novel compounds were also examined for their antioxidant activity (using Trolox Equivalent Antioxidant Capacity (TEAC) antioxidant assay as a measure of their overall ability to scavenge free radicals compared to antioxidant standards such as Trolox); compounds with free hydroxyl groups were more active than those one whose locking such and also the metal complexes showed more activity than Trolox. The antioxidant capacity was decreased in BTBGC, BTAGC and their complexes compared to curcumin and its oxovanadium (IV) complex, corroborating the importance of curcumin’s free phenolic OH groups for scavenging oxidants potential. Also, the presence of the methoxy group increases the activity.

Compounds of amine-substituted cyclic amines: synthesis and structures

Cyclic tetra-amines with amine substituents on the central carbon atom of C3 ring segments are readily prepared by reduction of nitro-substituted aza-macrocycles, formed by reactions of metal-ion amine compounds with formaldehyde and a nitro-alkane. Reactions of bis-(ethane-1,2-diamine)-copper(ii) or -nickel(ii) cations with formaldehyde and nitroethane form the trans (anti) and cis (syn) isomers of (6,13-dimethyl-6,13-di-nitro-1,4,8,11-tetra-azacyclotetradecane)-copper(ii) or -nickel(ii)) cations, which are readily reduced to form the trans and cis-6,13-diamino cations, from which the trans- and cis-amine substituted cyclic tetra-amines can be isolated. Similar reactions for the (3,7-diaza-nonane-1,9-diamine)-copper(ii) or -nickel(ii) cations lead to 6-methyl-1,4,8,11-tetra-azacyclotetradecane-6-amine. Amine-substituted cyclic tetra-amines with different ring sizes or alkyl substituents can similarly be prepared by using different diamines or alkyl-nitro compounds. This review is primarily about compounds formed by trans-6,13-diamino and 6-amino-1,4,8,11-tetraazacyclotetradecanes with d-transition-metal ions. The amines react with transition-metal ions in much the same manner as 1,4,8,11-tetraazacyclotetradecane (cyclam), forming compounds with isomeric configurations arising from the four chiral nitrogen centres of coordinated cyclam, the cis- or trans-configurations of the amine substituents and a form of geometrical isomerism arising from the relationship between the chiral coordinated cyclam configuration and the orientation of the substituents. The amine-substituted cyclams coordinate by the four cyclam nitrogen atoms, in planar or folded arrangements, and also by one or both of the amine substituents. Non-coordinated amine substituents can be protonated. The amine substituents can be modified by methylation, amide formation and reaction with aldehydes to form imines. The imines formed with functionalised aldehydes can be reduced to form variously functionalised secondary amine substituents. This all leads to complex coordination chemistry and X-ray crystallographic structure determinations have been critical in understanding the configurations present. Structures in the Cambridge Crystallographic Data Base of all relevant compounds are listed.