Peter Portius

The University of Sheffield | Sheffield · Department of Chemistry

This work demonstrates photocatalytic CO2 reduction by a noble-metal-free photosensitizer-catalyst system in aqueous solution under red-light irradiation. A water-soluble Mn(I) tricarbonyl diimine complex, [MnBr(4,4'-{Et2O3PCH2}2-2,2'-bipyridyl)(CO)3] (1), has been fully characterized, including single-crystal X-ray crystallography, and shown to re...

Reduction of copper(II) chloride using sodium ascorbate in the presence of pure sodium 5-nitro-tetrazolate (NaNT) forms copper(I) 5-nitrotetrazolate – a known initiatory explosive (DBX-1) – and the novel mixed-ligand copper(I) chloride 5-nitrotetrazolate coordination polymer Cu3Cl(N4C-NO2)2, as well as mixtures of both. The reaction is controlled b...

Reduction of copper(II) chloride using sodium ascorbate in the presence of pure sodium 5-nitro-tetrazolate (NaNT) forms copper(I) 5-nitrotetrazolate – a known initiatory explosive (DBX-1) – and the novel mixed-ligand copper(I) chloride 5-nitrotetrazolate coordination polymer Cu3Cl(N4C-NO2)2, as well as mixtures of both. The reaction is controlled b...

The dynamics of CO ligand scrambling in Fe(CO)5 has been investigated by linear infrared spectroscopy in supercritical xenon solution. The activation barrier for the Berry pseudorotation in Fe(CO)5 was determined experimentally to be Ea = 2.5 ± 0.4 kcal mol–1 by quantitative analysis of the temperature-dependent spectral line shape. This compares w...

The ease with which an energetic material (explosives, propellants, and pyrotechnics) can be initiated is a critical parameter to as-sess their safety and application. Impact sensitivity parameters are traditionally derived experimentally, at great cost and risk to safety. In this work we explore a fully ab initio approach based on concepts of vibr...

The rare octahedral EC6 coordination skeleton type is unknown for complexes with coordination centers consisting of group 14 elements. Here, the first examples of such EC6 species, the hexacoordinate homoleptic cyanido complexes E(CN)62–, E = Si, Ge, Sn, have been synthesized from element halides SiCl4, GeCl4 and SnF4 and isolated as salts with PPN...

Energetic materials (explosives, propellants and pyrotechnics) are used in a broad range of public and private sector applications. The design of novel, safe materials is therefore of critical importance. Until now, no physical mechanism has been described to rationalize the impact sensitivity properties of energetic materials. Investigation theref...

Sn(N3)2(py)2 and Sn(N3)2(pic)2 form upon reaction of tin(II) precursors with Me3SiN3 as tetracoordinate Lewis base adducts of Sn(N3)2. Solid Sn(N3)2(py)2 de-coordinates pyridine reversibly and releases microcrystalline Sn(N3)2. The friction-sensitive Sn(N3)2 reacts with a H-bond donor to form the salt-like and comparably stable guanidinium compound...

A convenient synthetic route to poly(tetrazolato) silicon complexes is described based on the four reactive centres of the N-rich, highly endothermic tetraazides of the type Si(N3)4(L2). Hypercoordinate azido(tetrazolato) silicon complexes Si(N3)2(N4C-R)2(L2), R = CH3, C6H5, 4-C6H4CH3 (4a, 5, 6, 7) and Si(N3)2(N4C-L)2 (9, L = 2-C5H4N), L2 = 2,2'-bi...

Using a novel approach in homoleptic nitrate chemistry, Sn(NO3)6(2-) (3c) as well as the previously unknown hexanitrato complexes Si(NO3)6(2-) (1c), Ge(NO3)6(2-) (2c) were synthesized from the element tetranitrates as salt-like compounds which were isolated and characterized using (1)H, (14)N, and (29)Si NMR and IR spectroscopies, elemental and the...

The first charge-neutral Lewis base adducts of tin(IV) tetraazide, [Sn(N3)4(bpy)], [Sn(N3)4(phen)] and [Sn(N3)4(py)2], and the salt bis{bis(triphenylphosphine)iminium} hexa(azido)stannate [(PPN)2Sn(N3)6] (bpy = 2,2′-bipyridine; phen = 1,10-phenanthroline; py = pyridine; PPN = N(PPh3)2) have been prepared using covalent or ionic azide-transfer reage...

First examples of coordinatively unsaturated, homoleptic azido complexes of low-valent group 14 elements are reported. A simple strategy uses low-valent precursors, ionic azide transfer reagents and bulky cations to obtain salt-like compounds containing E(N3)3(-) of Ge(II)/Sn(II) which are fully characterised, including XRD. Remarkably, these compo...

Picosecond time-resolved infrared spectroscopy was used to elucidate early photochemical processes in the diazido complexes M(Cp*)(N3)2(PPh3), M = Rh (1), Ir (2), using 266 nm and 400 nm excitation in THF, CH2Cl2, MeCN and toluene solutions. The time-resolved data have been interpreted with the aid of DFT calculations on vibrational spectra of the...

The chemistry of covalent azides of main group elements has developed rapidly during the last decade. Interest in this area of pseudohalogen chemistry arises from both fundamental questions of bonding in unusual, highly nitrogen-rich molecules as well as potential practical applications. Especially binary azides and homoleptic azido complexes were...

Pyrolysis of the homoleptic azido complex [P(N(3))(6)](-) was simulated using density functional theory based molecular dynamics and analyzed further using electronic-structure calculations in atom-centered basis sets to calculate the geometries and electronic structures. Simulations at 600 and 1200 K predict a thermally induced and, on the simulat...

Buy Article Permissions and Reprints Correction to Taming the Silicon Tetraazide BeastSynfacts 2011; 2011(01): 0043-0043 DOI: 10.1055/s-0030-1259150 The chemical formula in the last line of the Significance section is incorrect. Instead of Pb(N3)4 it should be Pb(N3)2. We apologize for this mistake.

Fast time-resolved infrared spectroscopic measurements have allowed precise determination of the rate of C-H activation of alkanes by Cp'Rh(CO) {Cp' = η(5)-C(5)H(5) or η(5)-C(5)Me(5); alkane = cyclopentane, cyclohexane and neopentane (Cp only)} in solution at room temperature and allowed the determination of how the change in rate of oxidative clea...

Fast time-resolved infrared spectroscopic measurements have allowed precise determination of the rates of activation of alkanes by Cp'Rh(CO) (Cp(') = η(5)-C(5)H(5) or η(5)-C(5)Me(5)). We have monitored the kinetics of C─H activation in solution at room temperature and determined how the change in rate of oxidative cleavage varies from methane to de...

Hochenergetisch und doch stabil: Die ersten Basen-Addukte von Siliciumtetraazid, [Si(N3)4(L2)] (L2= 2,2'-Bipyridin, 1,10-Phenanthrolin), wurden synthetisiert und vollständig charakterisiert (Bild: das Kugel-Stab-Modell des Addukts mit L2=2,2'-Bipyridin vor seinem FTIR-Spektrum; dunkelgrau C, weiß H, hellgrau Si, blau N). Bei Gehalten an reaktivem S...

Highly energetic and still stable: The first base adducts of silicon tetraazide, Si(N3)4(L2) (L2= bipyridine, 1,10-phenanthroline), were prepared and fully characterized (picture: the ball and stick model of the adduct with L2=2,2'- bipyridine in front of its FTIR spectrum; dark gray C, white H, light gray Si, blue N). The highly energetic compound...

The new silicates K2Si(NCE)6, E = O, S (1a,b) were synthesised directly by reaction of silicon tetrachloride with potassium cyanate or thiocyanate. 1a,b can be converted to the salts (PPN)2[Si(NCE)6] (2a,b) with bulky cations (PPN+ = N(PPh3)2+), which contain isolated silicate dianions. Reaction of 1a with diimines affords the hexacoordinate comple...

The photochemistry of (η6-C6H6)M(CO)3 (M = Cr or Mo) is described. Photolysis with λexc. > 300 nm of (η6-C6H6)Cr(CO)3 in low-temperature matrixes containing CO produced the CO-loss product, while lower energy photolysis (λexc. > 400 nm) produced Cr(CO)6. Pulsed photolysis (λexc. = 400 nm) of (η6-C6H6)Cr(CO)3 in n-heptane solution at room temperatur...

A combined experimental and theoretical study is presented of several ligand addition reactions of the triplet fragments (3)Fe(CO)(4) and (3)Fe(CO)(3) formed upon photolysis of Fe(CO)(5). Experimental data are provided for reactions in liquid n-heptane and in supercritical Xe (scXe) and Ar (scAr). Measurement of the temperature dependence of the ra...

(PPN)[P(N(3))(6)] (2) was synthesized by the metathesis of Na[P(N(3))(6)] (1) and (PPN)N(3) (PPN(+) = {(Ph(3)P)(2)N}(+)), allowing for the isolation and full characterization of a stable hexaazidophosphate(V) salt by (31)P and (14)N NMR, UV absorption, IR and Raman spectroscopy, elemental and thermal analyses, X-ray diffraction, and Hartree-Fock an...

The design of a new high-pressure infrared (IR) cell for carrying out picosecond time-resolved infrared (ps-TRIR) spectroscopy in supercritical fluids is described. We have employed thin (2 mm) MgF(2) windows in order to overcome possible undesirable nonlinear optical effects caused by the extremely high peak powers of ultrashort ultraviolet (UV)/v...

Fast time-resolved infrared (TRIR) experiments and density functional (DFT) calculations have been used to elucidate the complete reaction mechanism between alkanes and photolytically activated hydridotris(pyrazoly-1-yl)boratodicarbonylrhodium. TRIR spectra were obtained after photolysis of Rh(Tp4-tBu-3,5-Me)(CO)2 in n-heptane, n-decane, and cycloh...

The organometallic alkane complexes Re(Cp)(CO)(PF3)(alkane) and Re(Cp)(CO)2(alkane) have been detected after the photolysis of Re(Cp)(CO)2(PF3) in alkane solvent. NMR and time-resolved IR experiments reveal that the species produced by the interaction of n-pentane with [Re(Cp)(CO)(PF3)] are an equilibrium mixture of Re(Cp)(CO)(PF3)(pentane) and Re(...

We have used fast time-resolved infrared spectroscopy to characterize a series of organometallic methane and ethane complexes in solution at room temperature: W(CO)5(CH4) and M(η⁵[Graphic]C5R5)(CO)2(L) [where M = Mn or Re, R = H or CH3 (Re only); and L = CH4 or C2H6]. In all cases, the methane complexes are found to be short-lived and significantly...

Density functional calculations have been used to probe the electronic structures of Re(Cp)(CO)(2)Xe and Re(Cp)(CO)(PF3)Xe. The calculated CO stretching frequencies compare favorably with those determined experimentally. Our calculations of delta(Xe) and (3)J(Xe-F) for Re(Cp)(CO)(PF3)Xe represent the first for a well-characterized transition metal-...

Density functional calculations have been used to probe the electronic structures of Re(Cp)(CO)2Xe and Re(Cp)(CO)(PF3)Xe. The calculated CO stretching frequencies compare favorably with those determined experimentally. Our calculations of δXe and 3JXe-F for Re(Cp)(CO)(PF3)Xe represent the first for a well-characterized transition metal−noble gas co...

Photolysis of Re(iPrCp)(CO)2(PF3) in liquid or supercritical Xe yields two new compounds [Re(iPrCp)(CO)2Xe and Re(iPrCp)(CO)(PF3)Xe]. Re(iPrCp)(CO)(PF3)Xe has been characterized by NMR and IR spectroscopies. The compound is an organometallic Xe complex that has been characterized by using NMR spectroscopy and is shown to be longer-lived than other...

The first reactions of the germylidyne complexes trans-[X(dppe)2WGe(η1-Cp*)]·[toluene] (1-Cl·C7H8, X = Cl; 1-I·C7H8, X = I) with nucleophiles and electrophiles are reported. Treatment of 1-I·C7H8 with KBH4 in refluxing THF affords selectively the hydrido−germylidyne complex trans-[H(dppe)2WGe(η1-Cp*)] (2). Similarly, metathetical exchange of 1-I·C7...

The photochemistry of Fe(CO)5 (5) has been studied in heptane, supercritical (sc) Ar, scXe, and scCH4 using time-resolved infrared spectroscopy (TRIR). 3Fe(CO)4 ((3)4) and Fe(CO)3(solvent) (3) are formed as primary photoproducts within the first few picoseconds. Complex 3 is formed via a single-photon process. In heptane, scCH4, and scXe, (3)4 deca...

Time-resolved infrared (TRIR) spectroscopy, a combination of UV flash photolysis and fast infrared detection, is a powerful technique for probing excited states and detecting reaction intermediates. In this Perspective we highlight the application of TRIR to excited states by probing the nature of the lowest excited states of fac-[Re(CO) (3)(dppz-C...

Straightening out tin: The reaction of the dinitrogen complex 1 with the aryl tin(II) chloride 2 affords selectively the stannylyne complex 3. The molecular structure of 3 shows a very short WSn bond of 2.4902(8) Å and a linear coordinated tin atom (W-Sn-C=178.2(1)°). R=C6H3-2,6-Mes2, Mes=C6H2-2,4,6-Me3.

Nur 2.4902(8) Å lang ist die W-Sn-Bindung im Stannylidinkomplex 3, der aus dem Distickstoffkomplex 1 und dem Arylzinn(II)-chlorid 2 selektiv erhalten wurde. Die Kristallstrukturanalyse von 3 belegt außerdem das Vorliegen eines linear koordinierten Zinnatoms (W-Sn-C=178.2(1)°). R=2,6-Mes2C6H3, Mes=2,4,6-Me3C6H2).

The reaction of SiCl4 with an excess of (PPN)N3 (PPN+ = [(Ph3P)2N]+) affords selectively (PPN)2[Si(N3)6] (1). Simultaneous thermal analysis (TG-DTA) shows that the hexaazidosilicate salt is remarkably stable, melting at Tonex = 214 degrees C. Melting of 1 is followed by two distinct exothermic decomposition processes at Ton = 256 and 321 degrees C,...

The halogermylenes (Cp*GeX)n (1a, X = Cl, n = 1; 1b, X = Br, n = 2; Cp* = pentamethylcyclopentadienyl) were prepared in high yield by a redistribution reaction of GeCp*2 with GeX2(1,4-dioxane). The ionic compounds [Cp*Ge][GeX3] (2a, X = Cl; 2b, X = Br) were also formed to a small extent in this reaction. Treatment of trans-[Mo(dppe)2(N2)2] (3) (dpp...

Treatment of Cp*(CO)2WCNEt2 (1) (Cp*=η5-pentamethylcyclopentadienyl) with HCl affords the aminomethylene complex cis-Cp*(Cl)(CO)2WC(H)NEt2 (2). Complex 2 inserts stereoselectively GeCl2 into the tungsten–chlorine bond to afford cis-Cp*(GeCl3)(CO)2WC(H)NEt2 (3). Complex 3 can also be obtained directly from 1 and GeCl2(diox) (diox=1,4-dioxane) in...

The syntheses, spectroscopic data and the structures of molybdenum(IV) and tungsten(IV) aminomethylene complexes bearing 1,2-dithiolato ligands are presented. Oxidative decarbonylation of Cp*(CO)2MCNEt2 (1a,b) (a: M=Mo; b: M=W; Cp*=pentamethylcyclopentadienyl) with PhICl2 affords the aminocarbyne complexes cis-Cp*(Cl)2(CO)MCNEt2 (2a,b), which rea...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and...

Ideal S2 symmetry is shown by the [Ge(N3)6]2- ion (1) in the crystal lattice of the [N(PPh3)2] salt, where-as density functional calculations predict an S6-symmetric minimum structure for 1. Short interionic Na-N contacts lead to a reduction of the symmetry of the anion to C1 in crystalline [Na2(thf)3(Et2O)][Ge(N3)6], the product of the reaction of...

Ideale S2-Symmetrie weist das [Ge(N3)6]²⁻-Ion 1 im Kristall seines [N(PPh3)2]-Salzes auf, während Dichtefunktionalrechnungen eine S6-symmetrische Minimumstruktur von 1 voraussagen. Kleine interionische Na-N-Abstände führen zu einer Symmetrieerniedrigung des Anions auf C1 in einkristallinem [Na2(thf)3(Et2O)][Ge(N3)6], dem Produkt der Umsetzung von G...

trans-[MoCl2(dppe)2] [dppe is 1,2-ethane­diyl­bis­(di­phenyl­phos­phine), C26H24P2] was obtained as a side product from the reaction of trans-[Mo(dppe)2(N2)2] with Cp*GeCl to give the germyl­yne complex trans-[Cl(dppe)2Mo[triple-bond]Ge(η1-Cp*)]. The crystal structures of the hemi­pentane (0.5C5H12) and di­tetra­hydro­furan (2C4H8O) solvates of tra...

A short W−Ge triple bond and a η1-bound Cp* substituent are characteristic of the germylyne complexes 2⋅toluene that are obtained from the reaction of 1 with the germylene complexes [Cp*GeX] (W−Ge 2.302(1) Å for X=Cl). Density functional calculations show that there are significant electronic differences between germylyne and carbyne ligands. X=Cl,...

Reaction of GeCl2(C4H8O2) 1 with NaLOEt [LOEt = (C5H5)Co{P(O)(OEt)2}3] gave LOEtGeCl 2, which reacts with NaN3 to afford the germanium(II) azide LOEtGeN33. A dissociation equilibrium between 3 and the ions [LOEtGe]+ and N3− exists in solution, which is strongly dependent on the solvent polarity. Dissociation into ions is observed in solution for a...

The synthesis of the germanium(II) azide Tp′GeN3 (3) from Tp′GeCl (2) [Tp′ = HB(3,5-Me2pz)3] and NaN3 is reported and the crystal structures of 2 and 3 are compared.

Insertion of the chlorogermylene Cp*GeCl (2) (Cp* = pentamethylcyclopentadienyl) into the W−Cl bond of CpW(CO)3Cl (1) (Cp = cyclopentadienyl) affords the germyl complex CpW(CO)3GeCl2Cp* (3). Treatment of GeCp*2 with 1 equiv of HBr gives the bromogermylene [Cp*GeBr]2 (5). The crystal structures of the halogermylenes 2 and 5 are described. 2 is monom...