Heteroallene Insertions into Tin(II) Alkoxide Bonds.

A series of iso-carbamate complexes have been synthesized by the reaction of [Sn(OPr)] or [Sn(OBu)] with either aryl or alkyl isocyanates, ONC-R (R = 2,4,6-trimethylphenyl (Mes), 2,6-diisopropylphenyl (Dipp), isopropyl (Pr), cyclohexyl (Cy) and -butyl (Bu)). In the case of aryl isocyanates, mono-insertion occurs to form structurally characterized complexes [Sn{κ--R-NC(OPr)O}(μ-OPr)] (: R = Mes, : R = Dipp) and [Sn{κ--R-NC(OBu)O}(μ-OBu)] (: R = Mes, : R = Dipp). The complicated solution-state chemistry of these species has been explored using H DOSY experiments.

Tin(II) Ureide Complexes: Synthesis, Structural Chemistry, and Evaluation as SnO Precursors.

In an attempt to tailor precursors for application in the deposition of phase pure SnO, we have evaluated a series of tin (-) ureide complexes. The complexes were successfully synthesized by employing ,'-trialkyl-functionalized ureide ligands, in which features such as stability, volatility, and decomposition could be modified with variation of the substituents on the ureide ligand in an attempt to find the complex with the ideal electronic, steric, or coordinative properties, which determine the fate of the final products. The tin(II) ureide complexes - were synthesized by direct reaction [Sn{NMe}] with aryl and alkyl isocyanates in a 1:2 molar ratio.

Synthesis and structural characterization of hexa-μ-chlorido-μ-oxido-tetra-kis-{[4-(phenyl-ethyn-yl)pyridine-κ]copper(II)} di-chloro-methane monosolvate.

In the crystal structure of the title compound, [CuClO(CHN)]·CHCl, the core mol-ecular structure consists of a Cu tetra-hedron with a central inter-stitial O atom. Each edge of the Cu tetra-hedron is bridged by a chlorido ligand. Each copper(II) cation is coordinated to the central O atom, two chlorido ligands and one atom of the 4-phenyl-ethynyl-pyridine ligand.

Aerosol-assisted CVD of SnO from stannous alkoxide precursors.

The stannous alkoxides [Sn(OR)] [R = i-Pr, t-Bu, C(Et)Me, CHPh, CPh] have been synthesised by reaction of Sn(NR') with two equivalents of HOR [R' = Me, R = i-Pr; R' = SiMe, R = t-Bu, C(Et)Me, CHPh, CPh]. Single crystal X-ray diffraction analysis of the bis(diphenylmethoxide) (4) and bis(triphenylmethoxide) (5) species have shown them to comprise three-coordinate Sn(ii) centres through dimerisation in the solid state with the alkoxide units adopting transoid and cisoid configurations across the {SnO} cores respectively. Thermogravimetric analysis indicates clean decomposition and some evidence of volatility at temperatures >200 °C for all three aliphatic alkoxides, whereas both the diphenyl- and triphenylmethoxide compounds provide higher decomposition temperatures and, for the triphenylmethoxide derivative, a residual mass consistent with the formation of a carbon-containing residue.

Impact of the Alkyne Substitution Pattern and Metalation on the Photoisomerization of Azobenzene-Based Platinum(II) Diynes and Polyynes.

Trimethylsilyl-protected dialkynes incorporating azobenzene linker groups, MeSiC≡CRC≡CSiMe (R = azobenzene-3,3'-diyl, azobenzene-4,4'-diyl, 2,5-dioctylazobenzene-4,4'-diyl), and the corresponding terminal dialkynes, HC≡CRC≡CH, have been synthesized and characterized. The CuI-catalyzed dehydrohalogenation reaction between trans-[Ph(EtP)PtCl] and the deprotected dialkynes in a 2:1 ratio in PrNH/CHCl gives the platinum(II) diynes trans-[Ph(EtP)PtC≡CRC≡CPt(PEt)Ph], while the dehydrohalogenation polycondensation reaction between trans-[(BuP)PtCl] and the dialkynes in a 1:1 molar ratio under similar reaction conditions affords the platinum(II) polyynes, [-Pt(PBu)-C≡CRC≡C-]. The materials have been characterized spectroscopically, with the diynes also studied using single-crystal X-ray diffraction.

Experimental and Theoretical Investigation for the Level of Conjugation in Carbazole-Based Precursors and Their Mono-, Di-, and Polynuclear Pt(II) Complexes.

A series of trimethylsilyl-protected monoalkynes (Me3SiC≡C-R) and bis-alkynes (Me3 SiC≡C-R-C≡CSiMe3) incorporating carbazole spacer groups (R = carbazole-2-yl, carbazole-3-yl, carbazole-2,7-diyl, N-(2-ethylhexyl)carbazole-2,7-diyl, carbazole-3,6-diyl, N-(2-ethylhexyl)carbazole-3,6-diyl), together with the corresponding terminal monoalkynes (H-C≡C-R) and bis-alkynes (H-C≡C-R-C≡C-H), have been synthesized and characterized. The CuI-catalyzed dehydrohalogenation reaction between trans-[(Ph)(Et3P)2PtCl], trans-[(Et3P)2PtCl2], and trans-[(P(n)Bu3)2PtCl2] and the terminal alkynes in (i)Pr2NH/CH2Cl2 affords a series of Pt(II) mono- and diynes, while the dehydrohalogenation polycondensation reactions with trans-[(P(n)Bu3)2PtCl2] under similar reaction conditions yields four Pt(II) poly-ynes of the form trans-[(P(n)Bu3)2Pt-C≡C-R-C≡C-]n. The acetylide-functionalized carbazole ligands and the mono-, di-, and polynuclear Pt(II) σ-acetylide complexes have been characterized spectroscopically, with a subset analyzed using single-crystal X-ray diffraction.

Tuning a single ligand system to stabilize multiple spin states of manganese: a first example of a hydrazone-based manganese(III) spin-crossover complex.

A series of bis-chelate pseudo-octahedral mononuclear coordination complexes of manganese with the chromophore [MnN4 O2 ](n+) (n=0, 1) have been generated in all three principal oxidation states of this transition-metal center under ambient conditions by utilizing a readily tunable, versatile phenolic pyridylhydrazone ligand system (i.e., H2 (3,5-R(1) ,R(2) )-L; L=ligand).

Synthesis and structural studies of diorganotin(IV)-based coordination polymers bearing silaalkylphosphonate ligands and their transformation into colloidal domains.

The contribution of silaalkylphosphonic acids Me3SiCH2P(O)(OH)2 (1) and Me3SiC(CH3)2P(O)(OH)2 (2) as ligands was demonstrated for the first time by the isolation of new diorganotin(IV) phosphonates Et2Sn{OP(O)(OH)CH2SiMe3}(OSO2Me) (3), (Et2Sn)6{O3PC(CH3)2SiMe3}4(OSO2Me)4 (4), and Et2Sn(O3PCH2SiMe3) (5). X-ray crystallographic studies of 1-4 are presented. The structures of 1 and 2 adopt extended motifs by virtue of P-OH···O═P-type hydrogen bonding interactions.

New di-ferrocenyl-ethynylpyridinyl triphenylphosphine copper halide complexes and related di-ferricenyl electro-crystallized materials.

Three new neutral di-ferrocenyl-ethynylpyridinyl copper complexes, [L2(CuCl)2(PPh3)2] (), [L2(CuBr)2(PPh3)2] (), and [L2(CuI)2(PPh3)2] () were synthesized from the ferrocenyl-ethynylpyridine ligand (L) (), the appropriate copper halide CuX (with X = Cl(-), Br(-), I(-)) and triphenylphosphine. These neutral complexes were fully characterized by spectroscopic methods and by single crystal X-ray crystallography. Cyclic voltammetry in dichloroethane revealed chemically reversible ferrocenyl oxidation signals followed by characteristic "stripping reduction peaks" showing evidence for oxidation-product electro-crystallization.

Biomimetic polyorganosiloxanes: model compounds for new materials.

The chemistry of N-organosilylalkyl-substituted heterocyclic bases (thymine, adenine and cytosine) is described, covering the structures of model compounds, the synthesis of substituted oligo-siloxanes and a preliminary report of the synthesis of a poly(organosiloxane) with pendant N-alkyl(heterocycle) functionalities. N-Alkenylthymines CH2=CH(CH2)(n)T (T = thymine, n = 1 (1), 2 (2), 3 (3)) have been prepared and 2 hydrosilylated to form PhMe2Si(CH2)4T (5). Alternatively, 5 was prepared by reaction of PhMe2Si(CH2)4Br (6) with (O,O-SiMe3)2T, a method which has also been used to prepare PhMe2Si(CH2)4A (7) and PhMe2Si(CH2)4C (8) (A = adenine, C = cytosine).

Solution-processed mesoscopic Bi₂S₃:polymer photoactive layers.

The fabrication of solution-processed nontoxic mesoporous Bi2S3 structures is demonstrated and the suitability of these structures for use in hybrid solar cells investigated. Mesoporous Bi2S3 electrodes are prepared via thermal decomposition of a thin film composed of a bismuth xanthate single source precursor. The resultant Bi2S3 films are made up of regular needles with approximate dimensions of 50×500 nm, as confirmed by scanning electron microscopy (SEM).

Synthesis and materials chemistry of bismuth tris-(di-i-propylcarbamate): deposition of photoactive Bi2O3 thin films.

The bismuth carbamate Bi(O2CNPr(i)2)3, a tetramer in the solid-state, has been synthesized and used to deposit mixtures of bismuth oxides by aerosol-assisted chemical vapor deposition (AACVD). The nature of the deposited oxide is a function of both temperature and run-time. Initially, δ-Bi2O3 is deposited, over which grows a thick layer of β-Bi2O3 nanowires, the latter having an increasing degree of preferred orientation at higher deposition temperatures.

New organo- and amidozinc derivatives of primary amines.

Five new zinc derivatives of primary amines [R'ZnN(H)R]2 [R = SiPh3, R' = Me (1), N(SiMe3)2 (4); R = Si(NMe2)3, R' = Me (2), Et (3), N(SiMe3)2 (5)] have been synthesised by reaction of R'2Zn and H2NR. All five species are dimers in which the N-H groups are disposed in a trans manner about a central Zn2N2 ring. In 1 and 4 the coordination at zinc is trigonal planar, while in 2, 3, 5 the zinc is in a distorted tetrahedral environment due to additional Me2N: → Zn coordination from one SiNMe2 group.

New multi-ferrocenyl- and multi-ferricenyl- materials via coordination-driven self-assembly and via charge-driven electro-crystallization.

Three new tetra-ferrocenylethynylpyridinyl copper complexes, L4(CuI)4 (3), L4(CuBr)2 (4), and L4(CuCl)2 (5) have been prepared from the reaction of ferrocenylethynylpyridine (L)(2) with copper halides CuX (with X = I(-), Br(-), Cl(-)).The ligand 2 and the complexes 3-5 have been fully characterized by spectroscopic methods. The structures of 2-4 have been confirmed by single-crystal X-ray crystallography.

Di-chlorido-diphenyl-bis-(thio-urea-κS)tin(IV).

The title compound, [Sn(C6H5)2Cl2(CH4N2S)2], has been obtained from the reaction between Sn(C6H5)2Cl2 and SC(NH2)2. The asymmetric unit consists of one half of the mol-ecular unit, the remainder generated by a twofold rotation axis located along the Cl-Sn-Cl bonds. The Sn(IV) atom is coordinated by two phenyl groups, two Cl atoms and two thio-urea ligands in an all trans octa-hedral C2Cl2S2 environment.

Synthesis, characterization and selective de-esterification of diorganotinbis(O-methylphosphite)s.

A one-pot reaction between di-n-butyl/diethyl/dimethyltin dichloride and dimethylphosphite (MeO)2P(O)H in a solvent free medium (120 °C, 18 h) proceeds smoothly to yield the corresponding diorganotinbis(O-methylphosphite)s, [R2Sn(OP(O)(OMe)H)2]n [R = n-Bu (1), Et (2), Me (3)]. The identity of 1-3 has been established by IR, multinuclear ((1)H, (13)C, (31)P, (119)Sn) NMR, powder X-ray diffraction (PXRD) and X-ray crystallography. The coordination framework in each case adopts a one-dimensional structural motif comprising an infinite array of eight-membered [Sn-O-P-O]2 cyclic rings, with the phosphite ligands acting in a bridging bidentate mode.

Di(imino)aryltin(IV) dichlorides as tectons for heterometallic coordination compounds.

Hydrolysis of [2-{(CH2O)2CH}C6H4]2SnCl2 (1) [prepared from 2-[(CH2O)2CH]C6H4MgBr and SnCl4, in 2 : 1 molar ratio] gave [2-(O=CH)C6H4]2SnCl2 (2). Treatment of with the appropriate amine, in the absence of a solvent or catalyst, resulted in the isolation in high yields of [2-(RN[double bond, length as m-dash]CH)C6H4]2SnCl2 [R = 2'-C10H7 (3), 2',4',6'-Me3C6H2 (4), PhCH2 (5), Me2NCH2CH2 (6), 2'-PyCH2 (7)]. The reaction of with [Pd(COD)Cl2] provided the heterometallic species [Cl2Pd{2-(2'-PyCH2N[double bond, length as m-dash]CH)C6H4}2SnCl2] (8).

The Reaction and Materials Chemistry of [Sn (O) (OSiMe ) ]: Chemical Vapour Deposition of Tin Oxide.

[Sn (O) (OSiMe ) ] and [{Sn(OSiMe ) } ] have been used to deposit SnO thin films by chemical vapour deposition. Films derived from [Sn (O) (OSiMe ) ] comprise uniform cubes and are highly oriented, whereas those deposited from [{Sn(OSiMe ) } ] are made up of a continuous non-oriented layer with oriented cubes on the surface. The structure of a co-crystal, 2 Sn (O) (OSiMe ) ⋅[Sn(OSiMe ) ] ⋅4 THF, shows that [{Sn(OSiMe ) } ], a liquid at room temperature, adopts a μ-OSiMe -bridged dimeric structure.

Long-range intramolecular electronic communication in bis(ferrocenylethynyl) complexes incorporating conjugated heterocyclic spacers: synthesis, crystallography, and electrochemistry.

A new series of bis(ferrocenylethynyl) complexes, 3-7, and a mono(ferrocenylethynyl) complex, 8, have been synthesized incorporating conjugated heterocyclic spacer groups, with the ethynyl group facilitating an effective long-range intramolecular interaction. The complexes were characterized by NMR, IR, and UV-vis spectroscopy as well as X-ray crystallography. The redox properties of these complexes were investigated using cyclic voltammetry and spectroelectrochemistry.

New cyclotetrasiloxanes bearing sila-alkyl substituted side chains and their applications as templates for gold nanowires.

New sila-alkyl substituted cyclotetrasiloxanes, [RMe2SiCH2CH2(Me)SiO]4 [R = Ph(1), 2-thienyl(2), 2-furyl(3)] have been synthesized by a hydrosilylation reaction between 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, (D4(Vi)) and dimethylphenylsilane/dimethyl-2-thienylsilane/dimethyl-2-furylsilane in the presence of Karstedt's catalyst. X-ray crystallographic studies of 1 and 2 reveal all-trans conformation of the methyl groups bonded to puckered siloxane core and formation of 3D supramolecular assemblies by virtue of intermolecular C-H···π interactions. These siloxanes act as potential templates for expeditious one pot synthesis of gold nanowires of varying aspect ratios which are obtained by reduction of HAuCl4·3H2O with triethylsilane (CHCl3, RT).

Influence of crystallinity and energetics on charge separation in polymer-inorganic nanocomposite films for solar cells.

The dissociation of photogenerated excitons and the subsequent spatial separation of the charges are of crucial importance to the design of efficient donor-acceptor heterojunction solar cells. While huge progress has been made in understanding charge generation at all-organic junctions, the process in hybrid organic:inorganic systems has barely been addressed. Here, we explore the influence of energetic driving force and local crystallinity on the efficiency of charge pair generation at hybrid organic:inorganic semiconductor heterojunctions.

Di-μ-hydroxido-bis-[dimeth-yl(thio-cyanato-κN)tin(IV)].

The Sn(IV) atom in the centrosymmetric title complex, [Sn2(CH3)4(NCS)2(OH)2], adopts a distorted trigonal-bipyramidal coordination environment defined by two methyl C atoms and one bridging hydroxide group in the equatorial plane while the other bridging hydroxide group and the N atom of the thio-cyanate anion are in the apical >positions. The dinuclear species are linked through O-H⋯S and C-H⋯ S hydrogen-bonding inter-actions into a three-dimensional network.

Tetra-methyl-ammonium aqua-trichlorido-oxalatostannate(IV) monohydrate.

The Sn(IV) atom in the title compound, [(CH(3))(4)N][Sn(C(2)O(4))Cl(3)(H(2)O)]·H(2)O, obtained from the reaction between SnCl(4) and [(CH(3))(4)N](2)C(2)O(4)·2H(2)O, is six-coordinated by three Cl atoms, an O atom of a water mol-ecule and two O atoms from an asymmetrically chelating oxalate anion. The environment around the Sn(IV) atom is distorted octa-hedral. The anions are connected by the lattice water mol-ecule through O-H⋯O hydrogen bonds, leading to a layered structure parallel to (010).

μ(2)-Oxalato-bis-[triphen-yl(thio-urea-κS)tin(IV)].

The asymmetric unit of the binuclear title compound, [Sn(2)(C(2)O(4))(C(6)H(5))(6)(CH(4)N(2)S)(2)], consists of one half of the organotin(IV) mol-ecule. The remainder is generated by a twofold rotation axis passing through the mid-point of the oxalate C-C bond. The Sn(IV) atom exhibits a distorted trigonal-bipyramidal coordination environment with the phenyl groups in equatorial positions and the thio-urea and the monodentately bridging oxalate anion in axial positions.