Synthesis and structural studies on thioimides, R2C=NSR and sulfur diimides, R2C=NSN=CR2.

Reaction of Ph(2)C=O and py(2)C=O with Li[N(SiMe(3))(2)] and ArSCl (Ar = 2-O(2)NC(6)H(4), 2,4-(O(2)N)(2)C(6)H(3)) yielded Ph(2)C=NSAr (1a and 1b respectively) and py(2)C=NSAr (2a and 2b respectively). Reaction of fluorenone, C(12)H(8)C=O with Li[N(SiMe(3))(2)] and ArSCl under similar conditions afforded C(12)H(8)CNSAr (3a and 3b respectively). Whilst reaction of fluorenone with Li[N(SiMe(3))(2)] and SCl(2) in a 2 : 2 : 1 ratio afforded the sulfur-diimide, C(12)H(8)CNSNCC(12)H(8) (4), reaction of py(2)C=O with Li[N(SiMe(3))(2)] and SCl(2) under similar conditions afforded the thiazyl heterocycle [py(2)CNS]Cl (5) via intramolecular coordination.

Crystal structures, EPR and magnetic properties of 2-ClC6H4CNSSN˙ and 2,5-Cl2C6H3CNSSN˙.

The β-sheet structure associated with chlorinated aromatics (d(Cl···Cl)≈ 4.0 Å) has been implemented to drive formation of π-stacked structures of dithiadiazolyl radicals. Both title compounds exhibit an increase in paramagnetism above 150 K but solid-state EPR studies indicate that the origin of the paramagnetism in these two systems is different.

A chiral diphosphine as trans-chelate ligand and its relevance to catalysis.

The chiral diphosphine ligand R,R-trans-1,2-C(6)H(10)(NHCOC(6)H(4)PPh(2))(2), 1, gives the fluxional trans-chelate complexes [M(1)]X, 2a-2c, M = Au or Ag. It is suggested that a similar trans-chelate conformation may be present in the catalytic intermediate [Pd(1)].

Joining the crown family; the tetrameric, O-bridged macrocycle [{P(micro-N(t)Bu)}2(micro-O)]4.

The in situ reaction of the dianion [O_P(micro-N(t)Bu)]2(2-) with the dimer [ClP(micro-N(t)Bu)]2 gives the O_bridged macrocycle [{P(micro-N(t)Bu)}2(micro-O)]4 (1), being the largest crown-like phosph(III)azane of its type to be reported and having a structure that is directly related to the ubiquitous 12-crown-4.

Metal and ligand substitution of the aluminium tris-pyridyl ligands [RAl(2-py')(3)](-) (R = Et, (n)Bu, (s)Bu, (t)Bu; 2-py' = 2-pyridyl, 3-methyl-2-pyridyl, 5-methyl-2-pyridyl, 6-methyl-2-pyridyl).

A series of tris-pyridyl complexes [RAl(2-py)(3)]Li.thf [2-py = 2-pyridyl; R = Et (1); (n)Bu (2); (s)Bu (3), (t)Bu (4)] were prepared by the sequential reaction of AlCl(3) with RLi then 2-Li-py in thf. The related complexes [MeAl{2-(3-Me)py}(3)]Li(mu-Br)Li(thf)(3) (5), [MeAl{2-(5-Me)py}(3)]Li.

Mixed alkylamido aluminate as a kinetically controlled base.

The mechanisms by which directed ortho metalation (DoM) and postmetalation processes occur when aromatic compounds are treated with mixed alkylamido aluminate i-Bu3Al(TMP)Li (TMP-aluminate 1; TMP = 2,2,6,6-tetramethylpiperidide) have been investigated by computation and X-ray diffraction. Sequential reaction of ArC(=O)N(i-Pr)2 (Ar = phenyl, 1-naphthyl) with t-BuLi and i-Bu3Al in tetrahydrofuran affords [2-(i-Bu3Al)C(m)H(n)C(=O)N(i-Pr)2]Li x 3 THF (m = 6, n = 4, 7; m = 10, n = 6, 8). These data advance the structural evidence for ortho-aluminated functionalized aromatics and represent model intermediates in DoM chemistry.

Formation of N-bridgehead 1,2,5-thiadiazolium and selenadiazolium rings through an intramolecular cyclisation reaction.

Treatment of N-lithiopyridylketimide derivatives Li[R(C=N)py] (R=Ph, py) with ECl(2) (E=S, Se) affords the fused thiadiazolium and selenadiazolium salts [RC(6)H(4)N(2)E]Cl [1]Cl and [2]Cl containing a bridgehead N atom through intramolecular coordination.

The 6pi, phosphide-stabilised stannylene dianion [C6H4P2Sn]2-; the first member of a new class of Arduengo-type carbene analogues.

Dilithiation of 1,2-(PH2)2C6H4 with nBuLi followed by reaction with Sn(NMe2)2 in the presence of the Lewis base donor tmeda [Me2NCH2CH2NMe2] gives [(C6H4P2Sn)(Li.tmeda)2] , containing the phosphide-stabilised, 6pi stannylene dianion [C6H4P2Sn]2-.

Chemistry of pnictogen(III)-nitrogen ring systems.

This critical review covers significant recent advances in the chemistry of pnictogen(III)-nitrogen ring systems, also known as cyclopnict(III)azanes. The synthetic methodologies and reactions of the heavier pnictogen systems are compared with the well-developed chemistry of cyclophosph(III)azanes. Particular attention is focused on ring-oligomerization processes and the use of four-membered E(2)N(2) rings as building blocks for the synthesis of macrocyclic molecules.

Experimental and theoretical investigations of structural isomers of dichalcogenoimidodiphosphinate dimers: dichalcogenides or spirocyclic contact ion pairs?

A synthetic protocol for the tert-butyl-substituted dichalcogenoimidodiphosphinates [Na(tmeda){(EPtBu(2))(2)N}] (3 a, E=S; 3 b, E=Se; 3 c, E=Te) has been developed. The one-electron oxidation of the sodium complexes [Na(tmeda){(EPR(2))(2)N}] with iodine produces a series of neutral dimers (EPR(2)NPR(2)E--)(2) (4 b, E=Se, R=iPr; 4 c, E=Te, R=iPr; 5 a, E=S, R=tBu; 5 b, E=Se, R=tBu; 5 c, E=Te, R=tBu). Attempts to prepare 4 a (E=S, R=iPr) in a similar manner produced a mixture including HN(SPiPr(2)).

Bis(1 degree-amino)cyclodistib(III)azanes: the first structural characterization of cis and trans isomers of a single cyclodipnict(III)azane.

The dichlorocyclodistib(III)azane [ClSb(mu-NtBu)]2 (1) has been shown to exist as the cis isomer in the solid state. A series of bis(1 degree-amino)cyclodistib(III)azanes [R'NHSb(mu-NtBu)]2 (2, R' = tBu; 3, R' = Dipp; 4, R' = Dmp) has been prepared by the reaction of 1 with 2 equiv. of LiNHR'.

Self-assembly of coordination polymers: evidence for dynamic exchange between oligomers in solution and the isolation of a homochiral decagold(I) oligomer.

Reactions of the precursor molecules [Au2(mu-BINAP)(O2CCF3)2], 1a, racemic BINAP, 1b, S-BINAP (BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) with the easily exchanged linear bis(pyridine) ligand 1,2-trans-bis(4-pyridyl)ethylene (bipyen) gave the polymeric complex [{Au2(mu-R-BINAP)0.5(mu-S-BINAP)0.5(mu-bipyen)}n](CF3CO2)2n, 2a, but either the polymer [{Au2(mu-S-BINAP)(mu-bipyen)}n](CF3CO2)2n, 2b, or the remarkable oligomeric [Au10(mu-S-BINAP)5(mu-bipyen)4(kappa1-bipyen)2](CF3CO2)10, 3, respectively.

Structure and dynamics of tetrakis(thiophosphinato)resorcinarene complexes of silver(I), gold(I), and palladium(II).

The coordination chemistry of the tetrakis(thiophosphinato)resorcinarene sulfur-donor ligands [(C6H2CH{CH2CH2Ph})4{OC(O)R}4{OP(=S)Ph2}4] (L), where R = OCH2Ph, 4-C6H4CH3, C6H11, C4H3S, or OCH2CCH, is reported. Both silver(I) and gold(I) form cationic complexes of the type [LM2]2+, in which the ligand acts as a bis(chelate) in forming complexes with linear S-M-S (M = Ag or Au) stereochemistry. Gold(I) also forms the unusual complex [L(AuCl)2][LAu2]2+, which forms a supramolecular polymer through intermolecular aurophilic attractions.

A new route to antimony telluride nanoplates from a single-source precursor.

Aerosol-assisted chemical vapor deposition (AACVD) of Sb[(TePiPr2)2N]3 results in pure hexagonal Sb2Te3 nanoplates between 375 and 475 degrees C on glass substrates, with a potential for enhanced thermoelectric properties for novel nanodevices.

Syntheses and structures of magnesium and zinc boraamidinates: EPR and DFT investigations of Li, Mg, Zn, B, and In complexes of the [PhB(NtBu)2].- anion radical.

The first magnesium and zinc boraamidinate (bam) complexes have been synthesized via metathetical reactions between dilithio bams and Grignard reagents or MCl2 (M = Mg, Zn). The following new classes of bam complexes have been structurally characterized: heterobimetallic spirocycles {(L)mu-Li[PhB(mu-NtBu)2]}2M (6a,b, M = Mg, L = Et2O, THF; 6c, M = Zn, L = Et(2)O); bis(organomagnesium) complexes {[PhB(mu3-NtBu)2](MgtBu)2(mu3-Cl)Li(OEt2)3} (8) and {[PhB(mu3-NtBu)2](MgR)2(THF)2} (9a, R = iPr; 9b, R = Ph); mononuclear complex {[PhB(mu-NDipp)2]Mg(OEt2)2} (10). Oxidation of 6a or 6c with iodine produces persistent pink (16a, M = Mg) or purple (16b, M = Zn) neutral radicals {Lx-mu-Li[PhB(mu-NtBu)2]2M}.

Chalcogenide derivatives of imidotin cage complexes.

Reaction of the secocubane [Sn3(mu2-NHtBu)2(mu2-NtBu)(mu3-NtBu)] (1) with dibutylmagnesium produces the heterobimetallic cubane [Sn3Mg(mu3-NtBu)4] (4) which forms the monochalcogenide complexes of general formula [ESn3Mg(mu3-NtBu)4] (5a, E = Se; 5b, E = Te) upon reaction with elemental chalcogens in THF. By contrast, the reaction of the anionic lithiated cubane [Sn3Li(mu3-NtBu)4]- with the appropriate quantity of selenium or tellurium leads to the sequential chalcogenation of each of the three Sn(II) centres. Pure samples of the mono- or dichalcogenides are, however, best obtained by stoichiometric redistribution reactions of [Sn3Li(mu3-NtBu)4]- and the trichalcogenides [E3Sn3Li(mu3-NtBu)4]- (E = Se, Te).

Synthesis and structures of M[N(TePPri2)2-Te,Te']n (n = 2, M = Zn, Cd, Hg; n = 3, M = Sb, Bi): the first ditelluroimidodiphosphinato p- and d-block metal complexes.

Reactions of Na[N(TePPri2)2] with the appropriate metal halide produce the air-stable complexes M[N(TePPri2)2-Te,Te']n (n = 2, M = Zn, Cd, Hg; n = 3, M = Sb, Bi), which adopt distorted tetrahedral (M = Zn, Cd, Hg) and octahedral (M = Sb, Bi) structures, respectively.

Stable spirocyclic neutral radicals: aluminium and gallium boraamidinates.

Stable dark red (M = Al) or dark green (M = Ga) neutral radicals {[PhB(mu-NtBu)2]2M} are obtained by the oxidation of their corresponding anions with iodine, and EPR spectra supported by DFT calculations show that the spin density is equally delocalized over all four nitrogen atoms in these spiroconjugated systems.

Tetraphosphinite resorcinarene complexes: silver(I) capsule complexes.

Resorcinarene tetraphosphinite ligands, P4, react with silver(I) trifluoroacetate or silver(I) triflate, AgX, to give the corresponding [Ag4X4(P4)] complexes. The resorcinarene skeleton in these complexes adopts a boat conformation with the silver(I) phosphinite units on the horizontal, rather than the upright, arene units of the resorcinarene. The [Ag4X4(P4)] complexes react with free P4 ligand to yield the [Ag2X2(P4)] or [AgX(P4)] complexes, which are characterized in solution by NMR spectroscopy to have a conformation opposite to that of the [Ag4X4(P4)] complexes; the silver(I) phosphinite groups are on the upright arene rings of the resorcinarene "boat" instead of the horizontal arene units.

A chiral [2]catenane self-assembled from meso-macrocycles of palladium(II).

Reaction of trans-[PdX2(SMe2)2](X = Cl or Br) with the chiral ligand LL = 1,1'-binaphthyl-2,2'-(NHC(= O)-3-C5H4N)2 gave the [2]catenane complexes trans-[{(PdX2)2(micro-LL)2}2], which are formed by self-assembly from 4 units each of trans-PdX2 and LL. The catenation is favored by the formation of multiple hydrogen bonds between the constituent macrocycles (4 x NHClPd, 2 x NHO double bond C). If the ligand LL is racemic, each macrocycle trans-[(PdX2)2(micro-LL)2] is formed in the meso form trans-[(PdX2)2(micro-R-LL)(micro-S-LL)] but the resulting [2]catenane is chiral as a direct result of the catenation step.

Macrocyclic and lantern complexes of palladium(II) with bis(amidopyridine) ligands: synthesis, structure, and host-guest chemistry.

The reactions of [PdCl2(NCPh)2] in a 1:1 ratio with the bis(amidopyridine) ligands LL=C6H3(5-R)(1,3-CONH-3-C5H4N)2 with R=H (1a) or R=t-Bu (1b) give the corresponding neutral dipalladium(II) macrocycles trans,trans-[Pd2Cl4(mu-LL)2], 2a and 2b, which crystallize from dimethylformamide with one or two solvent molecules as macrocycle guests. The reaction of [PdCl2(NCPh)2] with LL in a 1:2 ratio gave the cationic lantern complex [Pd2(mu-LL)4]Cl4, 3c (LL=1b), and the reaction in the presence of AgO2CCF3 gave the corresponding trifluoroacetate salts [Pd2(mu-LL)4](CF3CO2)4, 3a (LL=1a) and 3b (LL=1b). These lantern complexes exhibit a remarkable host-guest chemistry, as they can encapsulate cations, anions, and water molecules by interaction of the guest with either the electrophilic NH or the nucleophilic C=O substituents of the amide groups, which can be directed toward the center of the lantern through easy conformational change.

Self-assembly using dynamic coordination chemistry and hydrogen bonding: mercury(II) macrocycles, polymers and sheets.

The self-assembly of extended metal-containing arrays is described based on dynamic coordination chemistry at mercury(II) with bis(amidopyridyl) ligands to form macrocycles, polymers, or sheets which can be further organized by hydrogen bonding between amide substituents. The ligands 1,2-C6H4[NHC(O)-4-C5H4N]2, 1, 1,2-C(6)H(4)[C(O)NHCH(2)-4-C(5)H(4)N](2), 2, and 1,2-C(6)H(4)[CH(2)C(O)NHCH(2)-4-C(5)H(4)N]2, 3 can adopt polar conformations and so can confer helicity in their complexes. Several macrocycles of formula [(HgX(2))(2)(micro-LL)(2)] (LL = 1, 2), with tetrahedral mercury(II) centers, were prepared in which individual molecules are further self-assembled via hydrogen bonding in the solid state to form one- or two-dimensional polymers or sheets.