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Titanosilicate amide [(tBuO)3SiO]3TiNEt2 can be easily converted into the first examples of acyclic alkali titanosilicates [MOTi{OSi(OtBu)3}3]2 (M = Li–Cs).

The preparation of dinuclear aluminum and gallium complexes with controlled M···M proximity (intermetal separation of 3.28–4.35 A) was achieved through direct chelation of the multidentate bis(diph...

The heterobimetallic complexes [Co(LtzE)3K(THF)2] [LtzE = [{4,5-(P(E)Ph2)2}tz]−; tz = 1,2,3-triazole; E = S(3), Se(4)] featuring high-spin cobalt centres, and [Ni(LtzE)3K(THF)2] [E = S(5), Se(6)] were synthesized through the self-assembly reaction of HLtzE [E = S(1), Se(2)], KOH or K0 and MCl2 (M = Co, Ni). Compounds 3–6 exhibit an unusual metallascorpionate-type anion formed by the coordination of three triazole units via a κ2-N,E mode to the transition-metal atom, and this anion further coordinates to a potassium cation through a κ3-N′,N′′,N′′′ fashion. Compounds 3 and 5 were used in the synthesis of 3d-metal heterometallascorpionates [M(LtzS)3Cu(PPh3)] [M = Co, (7), M = Ni (8)] and the bimetallic complex [Ni(LtzE)3Ni(NO3)(THF)] (9) through metathesis reactions, pointing to stable metallascorpionate anions in solution. The solution behavior of 3–9 was investigated by UV-visible spectroscopy, high-resolution mass spectrometry, electrochemical methods and by magnetic-susceptibility measurements. The molecular structures of 3–6, 8 and 9 were determined by single-crystal X-ray diffraction studies and exhibit M⋯M′ distances ranging from 3.52 to 3.88 A.

Carbon dioxide is readily fixed when reacting with either alumoxane dihydride [{MeLAl(H)}2(μ-O)] (1) or aluminum dihydride [MeLAlH2] (2) (MeL = HC[(CMe)N(2,4,6-Me3C6H2)]2-) to produce bimetallic aluminum formates [(MeLAl)2(μ-OCHO)2(μ-O)] (3) and [(MeLAl)2(μ-OCHO)2(μ-H)2] (5), respectively. Furthermore, [(MeLAl)2(μ-OCHO)2(μ-OH)2] (4) is easily obtained upon the reaction of 3 or 5 with H2O. The stability of the unusual dialuminum diformate dihydride core observed in 5 stems from the proximity of the Al centers allowing the formation of two Al-HAl bridges and precluding further hydride transfer to the HCO2 moieties. Contrary to this behavior, 1 and 2 react with CS2 giving cyclic alumoxane and aluminum sulfides [(MeLAl)2(μ-S)(μ-O)] (6) and [{MeLAl(μ-S)}2] (7), respectively. The molecular structures of 3-7 were characterized by IR, Raman, solution or solid-state (MAS) NMR spectroscopy and mass spectrometry and for 4-7 were characterized by X-ray diffraction studies. NMR kinetic studies and DFT calculations suggest that the mechanisms for the formation of 6 and 7 involve the transfer of a hydride group forming transient aluminum thioformate intermediates which proceed to form Al-S-Al moieties through the cleavage of C-S bonds and insertion of a sulfur atom, followed by the elimination of thioformaldehyde.

The reaction between 1-phenyl-tetrazole-5-thione (1) and the metal hydroxides MOH (M = Li, Na, K, Rb, Cs) in the presence of crown ethers led to the alkali metal complexes, [Li(15-crown-5)(SCN4Ph)] (2), [Na(15-crown-5)(SCN4Ph)] (5), [K(18-crown-6)(SCN4Ph)] (4), [Rb(18-crown-6)(SCN4Ph)] (5), [Cs(15-crown-5)2][SCN4Ph] (6), [{Cs(15-crown-5)(SCN4Ph)}] (6a), [Cs(18-crown-6)(SCN4Ph)] (7), [Cs(dibenzo-24-crown-8)(SCN4Ph)] (8) and [Cs2(dibenzo-24-crown-8)3(SCN4Ph)2] (8a). Compounds 2–8 were characterized by physical and analytical methods. X-ray diffraction studies performed on these compounds reveal that crown ether moiety precludes the ionic lattice formation. The tetrazole anion coordinates to the metal cation in a bidentate N,S fashion in 3–5 with the formation of a four-membered MSCN ring, whereas in 2, monodentate coordination through a N atom is observed. In contrast, cesium complexes 6, 6a, 7, 8 and 8a show a variety of structural arrangements including monomeric, dimeric and polymeric species, depending on the size of crown ether employed.

The reaction of MCp3 (M = Y, Nd, Sm, Gd) with the 4,5-bis(diphenylselenophosphoranyl)-1,2,3-triazole (LH) (1) in the presence of stoichiometric amounts of H2O afforded the trinuclear rare-earth metal complexes [(MCp)3(μ3-O)L4] [M = Y (3), Nd (4), Sm (5), Gd (4)]. The unforeseen formation of these multimetallic systems stems from the protonolysis reactions of the intermediate dicyclopentadienyl rare-earth complexes MCp2L with H2O. This was confirmed by the transformation of YCp2L (2) to (YCp)3(μ3-O)L4 (3) under controlled conditions. X-ray diffraction studies reveal that 3–6 possess a trinuclear [M3(μ3-O)] core with M–Se contacts featuring M⋯M interactions. The magnitude of the M⋯M separations is controlled by the constrictions imposed on the planar [M3(μ3-O)] core by the surrounding M2ON2 and M2ON ring systems. DFT calculations were performed on 3 which was used as a model compound for the heavier rare-earth metals providing insight into the nature of the Y–Se and Y–N contacts around the M3(μ3-O) core.

The reaction of metalloxanes [{MeLM(OH)}2(μ-O)] [M = Al (1), Ga (2); MeL = CH{CMe(NAr)}2–, Ar = 2,4,6-Me3C6H2, Me = methyl] with an excess of BH3·D (D = tetrahydrofuran (THF), SMe2) affords annular metallaborate systems achieved through M–O–M cleavage. Compound 1 led exclusively to the formation of eight-membered ring systems [{MeLAl(μ-O){B(OnBu)}(μ-O)}2] (3) and [{MeLAl(μ-O)(BH)(μ-O)}2] (6), while for 2 the unprecedented six-membered ring systems [{(MeLGa)2(μ-O)}(μ-O)2{B(OnBu)}] (4) and [(MeLGa)(μ-O)2{(BOnBu)2(μ-O)}] (5) were observed. The use of BH3·THF with 1 and 2 led to the concomitant THF ring-opening reaction, while with BH3·SMe2 in THF no such reaction was observed. The metallaborates [MeLAl{OB(pinacol)}(OH)] (7) and [{MeLGa(OB(pinacol))}2(μ-O)] (8) were synthesized from pinacolborane and the corresponding metalloxane, providing structural evidence that supports the reaction pathways proposed for the formation of 3–6. Density functional theory studies were performed on 3–5 to assess the effect of ...

Carbon dioxide is readily fixed when reacting with either alumoxane dihydride [{MeLAl(H)}2(μ-O)] (1) or aluminum dihydride [MeLAlH2] (2) (MeL = HC[(CMe)N(2,4,6-Me3C6H2)]2-) to produce bimetallic aluminum formates [(MeLAl)2(μ-OCHO)2(μ-O)] (3) and [(MeLAl)2(μ-OCHO)2(μ-H)2] (5), respectively. Furthermore, [(MeLAl)2(μ-OCHO)2(μ-OH)2] (4) is easily obtained upon the reaction of 3 or 5 with H2O. The stability of the unusual dialuminum diformate dihydride core observed in 5 stems from the proximity of the Al centers allowing the formation of two Al-HAl bridges and precluding further hydride transfer to the HCO2 moieties. Contrary to this behavior, 1 and 2 react with CS2 giving cyclic alumoxane and aluminum sulfides [(MeLAl)2(μ-S)(μ-O)] (6) and [{MeLAl(μ-S)}2] (7), respectively. The molecular structures of 3-7 were characterized by IR, Raman, solution or solid-state (MAS) NMR spectroscopy and mass spectrometry and for 4-7 were characterized by X-ray diffraction studies. NMR kinetic studies and DFT calculations suggest that the mechanisms for the formation of 6 and 7 involve the transfer of a hydride group forming transient aluminum thioformate intermediates which proceed to form Al-S-Al moieties through the cleavage of C-S bonds and insertion of a sulfur atom, followed by the elimination of thioformaldehyde.

The monosubstituted complex [MoO2Cl2{κ2-O,O′-{4,5-(P(O)Ph2)2tzH}}] (tz = 1,2,3-triazole) (4) and [Mo(NtBu)2{κ2-N,S-{4,5-(P(S)Ph2)2tz}}2] (12), and the disubstituted complexes, [MoO(NtBu){κ2-O,N-{4,5-(P(O)Ph2)2tz}}2] (8) and [Mo(NtBu)2{κ2-N,E-{4,5-(P(E)Ph2)2tz}}2] [E = O(9), S(10), Se(11)] were prepared using the corresponding ligands [{(4,5-(P(E)Ph2)2tz}H] [E = O(1), S(2), Se(3)] and molybdenum precursors, MoXYCl2(dme) (X = Y = O; X = O, Y = NtBu; X = Y = NtBu, dme = dimethoxyethane). The disubstituted complexes 4, 8, 9 and 11 were obtained regardless of the ligand/metal ratio used in the reaction (1:1 or 2:1). Complexes 8 and 9 exhibit one type of geometric isomer in solution while 10 and 11 show two types of isomers in solution. In these compounds at least one isomer with C2 symmetry is observed. Complexes 4, 8, 9 and 10 were characterized by X-ray diffraction analysis.

The reaction of ammonium salts of benzylferrocenyldithiophosphonate ligands [NH 4 ][S 2 P(OR)(Fc)] [R = Bz ( 1 ), 4-( i Pr)-Bz ( 2 ), 4-( t Bu)-Bz ( 3 ), 4-(Ph)-Bz ( 4 ), 3-(OBz)-Bz ( 5 ); Bz = benzyl, Fc = ferrocenyl] with organotin(IV) chlorides Ph 2 SnCl 2 , n Bu 2 SnCl 2 and Ph 3 SnCl, gave the corresponding organotin(IV) benzylferrocenyldithiophosphonates [Ph 2 Sn{S 2 P(OR)(Fc)} 2 ] [R = Bz ( 6 ), 4-( i Pr)-Bz ( 7 ), 4-( t Bu)-Bz ( 8 ), 4-(Ph)-Bz ( 9 ), 3-(OBz)-Bz ( 10 )], [ n Bu 2 Sn{S 2 P(OR)(Fc)} 2 ] [R = Bz ( 11 ), 4-(Ph)-Bz ( 12 )] and [Ph 3 Sn{S 2 P(OBz)(Fc)}] ( 13 ). Compounds 6 – 13 were characterized by elemental analyses, infrared, 1 H, 13 C{ 1 H}, 31 P{ 1 H} and 119 Sn{ 1 H}NMR spectroscopy and ESI mass spectrometry, while complexes 6 , 11 and 13 were also characterized by single-crystal X-ray diffraction studies. The dithiophosphonate ligands display an anisobidentate coordination mode upon interaction with the metal center. The solid-state structures of the disubstituted complexes 6 and 11 exhibit a trans arrangement for the ferrocenyl groups from the dithiophosphonate ligands.

Equimolar and excess ratio reactions of ligands [H{4,5-(P(E)Ph2)2tz}] [tz = 1,2,3-triazole; E = S (1), Se (2)] with Ti(NR2)4 (R = Me, Et) yielded the disubstituted complexes [Ti(NR2)2{κ2-N,E-(4,5-(P(E)Ph2)2tz}2] [E = S, R = Me (3), Et (4); E = Se, R = Me (5), Et (6)], while the reactions of 1 and 2 with Ti(NEt2)2Cl2 gave the monosubstituted complexes [Ti(NEt2)Cl2{κ2-N,E-(4,5-(P(E)Ph2)2tz}] [E = S (7), Se (8)]. The reaction of M(NR2)4 (M = Zr, Hf, R = Me, Et) with 1 and 2 failed. However, the zirconium and hafnium disubstituted complexes, [M(NR2)2{κ2-N,E-(4,5-(P(E)Ph2)2tz}2] [M = Zr, E = S, R = Me (11), Et (12); M = Hf, E = S, R = Me (13), Et (14); M = Zr, E = Se, R = Et (15); M = Hf, E = Se, R = Et (16)] were obtained from the silylated derivatives [SiMe3{κ1-N-(4,5-(P(E)Ph2)2tz}] [E = S(9), Se(10)] and the corresponding metal amides M(NR2)4. In addition, the facile hydrolysis of 5, 7 and 8 with trace amounts of water led to the isolation of compounds 17–19, which contain Ti–O–Ti frameworks.

The reaction of metalloxanes [{

The reaction of benzylferrocenyldithiophosphonate ligands [NH4][S2P(OR)(Fc)] [R = Bz (1), 4-(iPr)-Bz (2), 4-(tBu)-Bz (3), 4-(Ph)-Bz (4), 3-(OBz)-Bz (5); Bz = benzyl, Fc = ferrocenyl] with organotellurium iodides, C4H8TeI2 and C8H8TeI2, yielded the corresponding tellurium(IV) dithiophosphonate complexes [C4H8Te{S2P(OR)(Fc)}2] [R = Bz (6), 4-(iPr)-Bz (7), 4-(tBu)-Bz (8), 4-(Ph)-Bz (9), 3-(OBz)-Bz (10)] and [C8H8Te{S2P(OR)(Fc)}2] [R = Bz (11), 4-(iPr)-Bz (12), 4-(tBu)-Bz (13), 4-(Ph)-Bz (14), 3-(OBz)-Bz (15)]. Compounds 6–15 were characterized by elemental analyses, infrared, 1H, 13C, 31P and 125Te NMR spectroscopy and EI mass spectrometry, while complexes 6, 11 and 14 were also characterized by single-crystal X-ray diffraction studies. The dithiophosphonate ligands display an anisobidentate coordination mode upon interaction with the metal center. The solid-state structures show ferrocenyl groups in the dithiophosphonate ligands adopting trans arrangements.

The reaction of CpTiCl3 with HLx [HLx = methyl 3-(4′-X-phenyl)-3-hydroxy-2-propenedithioate ligands; X = H(1), Me(2), OMe(3), Cl(4), Br(5)] in the presence of NEt3 yielded the corresponding half-sandwich complexes TiCpCl2(Lx) [X = H(6), Me(7), OMe(8), Cl(9), Br(10)]. Compounds 1–10 were characterized by elemental analyses, infrared, 1H and 13C NMR spectroscopy and EI mass spectrometry, while ligands 1,3–5 and complexes 6–10 were also characterized by single-crystal X-ray diffraction studies. The structural arrangements observed in 1,3–5 include an intramolecular O–H⋯S hydrogen bond. The metal center in 6–10 exhibits a square pyramidal geometry by means of the O∩S coordination mode of ligands, which led to the racemic form of the A, C enantiomers, associated by an inversion center.

The alkaline–earth metal complexes, [MI{4,5-(P(Se)Ph 2 ) 2 tz}] 2 (thf) n [M = Mg, n = 2 ( 2 ); M = Ca, n = 4 ( 3 ); M = Sr, n = 6 ( 4 ); M = Ba, n = 7 (5); tz = 1,2,3-triazole], [Mg{4,5-(P(Se)Ph 2 ) 2 tz} 2 (thf) 4 ] ( 6 ) and [M{4,5-(P(Se)Ph 2 ) 2 tz} 2 (thf)] 2 (M = Ca ( 7 ), Sr ( 8 ), Ba ( 9 ), were prepared by metathesis reactions between [Na{4,5-(P(Se)Ph 2 ) 2 tz}] and MI 2 (M = Mg, Ca, Sr, Ba) in different molar ratios. The structural arrangements observed in 2 – 5 and 7 – 9 include bimetallic species comprising inorganic M 2 N 4 rings, while the geometrical array present in the ligands in these systems enables M–Se bonding. In addition, easy hydration of complexes 3 and 8 by adventitious water during their crystallization gave the ionic complex [{Ca{4,5-(P(O)Ph 2 )(P(Se)Ph 2 )tz}(thf) 2 (H 2 O)} 2 ] 2+ 2[I] − ( 3a ) and the hydrate complex [Sr{4,5-(P(Se)Ph 2 tz) 2 } 2 (thf)(H 2 O) 0.21 ] 2 ( 8a ), respectively. Complex 3a is formed by the almost complete hydrolysis of the Ca–Se(P) bonds and the displacement of the iodine atoms by water molecules in the coordination sphere of the metal, while 8a exhibits only partial coordination of water molecules to the strontium atoms leaving the Sr–Se bonds intact.

Controlled hydrolysis of (Me)LGaCl2 ((Me)L = HC[(CMe)N(2,4,6-Me3C6H2)]2(-)) (1) in the presence of a N-heterocyclic carbene, as a HCl acceptor, led to the unprecedented molecular galloxane dihydroxide [{(Me)LGa(OH)}2(μ-O)] (2) in high yield. Compound 2 was used in the assembly of the heterobimetallic galloxanes with group 4 metals [{((Me)LGa)2(μ-O)}(μ-O)2{M(NR2)2}] (M = Ti, R = Me (6); M = Zr (7), Hf (8), R = Et).

Reactivity studies of aluminoxane hydroxide and hydrogensulfide [{MeLAl(EH)}2(μ-O)] {MeL = CH[CMe(NAr)]2– (Ar = 2,4,6-Me3C6H2); E = O (1), S (2)} with Group 4 amides led to the molecular heterobimetallic aluminoxanes [(MeLAlO)2(μ-O){M(NR2)2}] [M = Ti, R = Me (3); M = Zr, R = Me (4), Et (5); M = Hf, R = Me (6), Et (7)] and aluminoxane sulfides [(MeLAlS)2(μ-O){M(NR2)2}] [M = Ti, R = Me (8), Et (9); M = Zr, R = Me (10), Et (11); M = Hf, R = Me (12), Et (13)], respectively. The structural analyses of these compounds reveal six-membered inorganic cores that exhibit Al–E–M (E = O, S; M = Ti, Zr, Hf) moieties. Compounds 10–13 exhibit strong O···M (M = Zr, Hf) transannular bonding, whereas 8 and 9 exhibit relatively short Ti–S bond lengths. DFT calculations performed on 8–13 at the B3LYP/LANL2DZ level of theory indicate that the titanium atoms in 8 and 9, despite having the lowest transannular bond index, have the highest total Wiberg bond indexes. This can be rationalized in terms of the high Ti–S bond indexes, which indicate an important degree of electron density delocalized from the sulfur atoms to the titanium atom.

The alkaline earth metal complex [Mg{4,5-(P(S)Ph2)2}2tz}2(thf)4] (2) and the bimetallic complexes, [M{4,5-(P(S)Ph2)2}2tz}2(thf)]2 [M = Ca (3), Sr (4), Ba (5)], [SrI{4,5-(P(S)Ph2)2tz}2(thf)3]2 (6), and [{BaI(4,5-(P(S)Ph2)2tz)}2(thf)7] (7) were prepared in good yields from the metathesis reactions of the potassium salt of 4,5-bis(diphenylthiophosphoranyl)-1,2,3-triazole [H{4,5-(P(S)Ph2)2tz}] (1) and MI2 (M = Ca, Sr, Ba), whereas the tetrametallic magnesium hydroxide [Mg2(μ-OH){4,5-(P(S)Ph2)2}2tz}3]2 (8) was obtained as the hydrolysis product from the starting material (MgnBuCl) and 1. The NMR study of 2–8 in solution suggests the formation of solvated species in CD3OD-d4, whereas for 4, 5, and 6 a fluxional behavior is observed in CD2Cl2. The structural analyses of 3–5, 6, and 7 in solid state reveal in all cases a central core defined by M2N4 heterocycle bearing M–S bonding. The degree of aggregation observed for these compounds depends significantly on the size of the metal atom as well as on the metal-ligand molar ratio employed for each reaction.

Equimolar and excess ratio reactions of AlMe(3) and Al(i)Bu(3) with the ligands 4,5-(P(E)Ph(2))(2)tzH (tz = 1,2,3-triazole; E = O (1), S (2), Se(3)) were performed, showing a vast variety of coordination modes. The products obtained, [AlR(2){kappa(2)-O,O'-[4,5-(P(O)Ph(2))(2)tz]}] (R = Me (4), (i)Bu (5)), [AlR(2){kappa(3)-N,N',S-[4,5-(P(S)Ph(2))(2)tz]}(mu-tz)](2) (R = Me (6), R = (i)Bu (7)), [AlMe(2){kappa(2)-N,Se-[4,5-(P(Se)Ph(2))(2)tz]}] (8), [Al{kappa(2)-N,Se-[4,5-(P(Se)Ph(2))(2)tz]}(3)] (9), [AlR(2){kappa(2)-O,O'-[4,5-(P(O)Ph(2))(2)tz]}-(N'-AlR(3))] (R = Me (10), (i)Bu (11)), and [AlR(2){kappa(2)-N,S-[4,5-(P(S)Ph(2))(2)tz]}-(N'-AlR(3))] (R = Me (12), R = (i)Bu (13)), were characterized by spectroscopic methods, and the structures of 1, 4, 6, 7, 9, 10, and 12 were obtained through X-ray diffraction studies. Theoretical calculations were performed on the deprotonated ligands and on selected compounds to obtain information regarding the coordination variety observed for these compounds.

We report the synthesis and spectroscopic characterization of organometallic Te(IV) complexes bearing the seven-membered azepane-1-carbodithioate ligand and four different types of tellurium(IV) heterocycles; [C4H8Te{S2C-N(CH2)6}2](2),[C8H8Te{S2C-N(CH2)6}2](3),[C4H8OTe{S2C-N(CH2)6}2](4)and [C5H10Te{S2C-N(CH2)6}2](5). Compounds 2–5, obtained in a 2:1 stoichiometric ratio, are air-stable for long periods of time, but readily decompose in solution. They have been characterized by elemental analyses, IR, FAB+–MS, and multinuclear NMR (1H, 13C, and 125Te) spectroscopy. The molecular structures of 2 and 5 were established by single-crystal X-ray diffraction studies. The geometrical arrangement around the tellurium atom can be described as a distorted trigonalbipyramid or sawhorse structure, typical for tellurium atom, where the lone pair is apparently stereochemically active, occupying an equatorial position. The coordination mode for the azepane-1-carbodithioate ligands is considered as anisobidentate. Due to the orthogonal arrangement of the dithiocarbamate groups around tellurium, it is difficult for other atoms to approach and in consequence there are not intermolecular secondary interactions.

Herein we report on the preparation of hydrated ammonium salts of the dithiophosphonic acids (RO)(Fc)P(S)(SH) (R = derivative of benzyl) featuring [(NH 4 · H 2 O) 2 ] 2+ cations formed by N–H⋯O hydrogen bonds. Interaction of these cations with the PS 2 − units gives rise to unprecedented 2D networks, formed solely by hydrogen bonds. These unique networks containing two- and three centered hydrogen bonds are valuable examples of the acceptor properties of sulfur atoms.

The reaction of the LAl(SH)(µ‐O)P(OEt)2 (L=HC[C(Me)NAr]−, R=2,6‐di‐iPr2C6H3) ligand (1) with GaMe3 in toluene led to the isolation of a unique heterobimetallic aluminophosphite [κ2‐P, S‐LAl(µ‐S)(µ‐O)P(OEt)2]GaMe2 (2). Compound 2 is a potential secondary building unit (SBU) for heterometallic materials and represents the first example of structurally characterized lipophilic phosphite of the p‐block metals, in which the metal is coordinated by the phosphorus atom. Moreover, it represents the first structurally characterized example where a gallium atom is coordinated to both, sulfur and phosphorus atoms. Furthermore, it contains a rare carbon‐free “true” 5‐membered heterocycle Al‐O‐P‐Ga‐S.

The 1-oxa-4,6-dithia-, 1,3,6-trithia-, 1-aza-4,6-dithia-, 1-aza-4,6-dioxa-, 1-thia-4,6-dioxa- and 1,3,6-trioxametallocanes possess a strong 1,5 transannular interaction through an acceptor atom M [Ge(IV), Sn(IV), Pb(IV), As(III), Sb(III) and Bi(III)] and an X donor (O, S, NR). The conformation adopted by the metallocane ring has exhibited various conformations along with the extreme conformations boat–boat, boat–chair and chair–chair. The structural diversity observed in these eight-membered rings results in a variety of coordination numbers, as well as in the presence of polymeric structures. The purpose of the present review is to highlight the relationship between the strength of the transannular bonding and the resulting molecular structures. Factors such as coordination number, electronegativity and steric effects are revised.

Ca[(Ph2PO)2N]2·nTHF (2) was obtained by direct synthesis from tetraphenylimidodiphosphinic acid and Ca° in THF. X-ray quality single crystals of Ca2[(Ph2PO)2N]4·H2O (3) and Ca[(Ph2PO)2N]2·2C4H8O3 (4) were obtained upon crystallization of 2 under different conditions. The solid-state structure of 3 reveals a Ca2O3 core in which the two hexacoordinated calcium metals are linked together by three μ-oxygen atoms from three independent tetraphenylimidodiphosphinate ligands. Compound 4 is a monomeric octahedral complex bearing two tetraphenylimidodiphosphinate ligands in the equatorial plane and two α-hydroperoxidated THF molecules, formed in situ, in the axial positions. Compound 4 represents the first example of a metal center exhibiting this type of hydroperoxidation behavior.

The alkaline 1-phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate salts, M[C6H5N4CS] (M = Li (1), Na (2), K (3), Rb (4) and Cs (5)) were obtained and characterized by means of mass spectrometry (FAB+) and NMR (1H; 13C) spectroscopy. The structures of Na (2), K (3), Rb (4) and Cs (5) compounds were determined by X-ray diffraction methods. The ligand shows a rich variety of coordination patterns with the alkaline cations. The formation of a four-membered ring MSCN in the compounds with heavier alkali cations (K, Rb and Cs) is shown. In all the cations the coordination number around it increases with the ionic radius. Compounds with Cs+ and Rb+ exhibited the formation of Cs-C and Rb-C interactions with the phenyl group. Strukturuntersuchungen an Alkali-1-Phenyl-1H-1, 2, 3, 4-tetrazol-5-thiolat-Salzen: Ein Beispiel der Periodizitat von Alkalimetallionen Die Alkali-1-phenyl-1H-1, 2, 3, 4-tetrazol-5-thiolat-Salze M[C6H5N4CS] (M = Li (1), Na (2), K (3), Rb (4) und Cs (5)) wurden hergestellt und durch Massenspektrometrie (FAB+) und NMR-Spektroskopie (1H, 13C) charakterisiert. Die Strukturen von 2, 3, 4 und 5 wurden rontgenographisch ermittelt. Die Ligandionen zeigen eine reichhaltige Variation des Koordinationsverhaltens mit den Alkalimetallionen. In den Verbindungen mit den Kationen K+, Rb+und Cs+ liegen viergliedrige Ringe MSCN vor. Die Koordinationszahl an den Kationen steigt mit der Grose des Ionenradius an. Die Verbindungen mit Rb+und Cs+ weisen Rb···C- und Cs···C-Kontakte mit der Phenylgruppe auf.

New complexes of the pinch-porphyrin family were obtained from the dimethylester of (proto-, meso-, and deutero-porphyrinato)iron(III) with the ligand [N,N'-bis-pyridin-2-ylmethyl-propane-1,3-diamine] 1-3 and with the ligand [N-pyridin-2-ylmethyl-N'-[3-[(pyridin-2-ylmethyl)-amino]-propyl]-propane-1,3-diamine] 4-6. The UV/VIS studies of 1-6 indicate an increase in the distortion of the ligand field excited state. The 1H NMR spectra of 1-6 at RT and over the range 223-328 K show iron(III)-complexes with quantum mixed spin state (qms) S=5/2, S=3/2. The chemical shifts of the meso protons are consistent with qms state S=3/2, S=5/2, where the S=3/2 spin state is lowest in energy. For methyl-heme the chemical shifts are also consistent with a qms state but now the S=5/2 ground state is lowest in energy. ESR spectra of 1-6 show two different species, B and C, of iron(III) with qms, S=5/2, S=3/2 consistent with the 1H NMR results. Species B with 70% of S=5/2 and species C with 72.5% of S=3/2. The catalytic activity as peroxidase of 1-6 was quantified by guaiacol test; their theoretical maximum rate constants were k(cat) approximately 10(2)-10(3) M(-1) s(-1). A quantitative empirical correlation is found: the higher the 32 spin contribution to the qms state and the higher proportion of this species into the samples, the higher the peroxidase activity. Such a correlation was also obtained for pinch-porphyrins already reported.

The cyclic alumosiloxane [{LAl(μ-O)(Ph(2)Si)(μ-O)}(2)] (3) and alumosilicate [{LAl(μ-O){((t)BuO)(2)Si}(μ-O)}(2)] (4) were obtained by reaction of the appropriate R(2)Si(OH)(2) precursor (R = Ph, O(t)Bu) with [{LAl(H)}(2)(μ-O)] (1), providing a nice illustration of the Loewenstein rule at work at the molecular level.

The reaction between α,β-unsaturated derivatives of monohydrazones of 1,2-dicarbonylic compounds (namely the 1-dimethylhydrazono-4-phenylbuten-3-ones (1a–c)) and di-iron nonacarbonyl affords the novel mono- and trinuclear Fe (0) complexes 2b–c and 3a–c, respectively, with a σ-N and an η2-coordination upon the CC bond of the α,β-unsaturated system for the former compounds, which actually generate six-membered metallocycles. With the latter complexes 3a–c, the main structural features are the unexpected presence of a dinuclear iron unit displaying at one end both the σ-N and σ-O coordination and at the other an η2-coordination upon the CN double bond giving rise to an unique organometallic arrangement in the heteroatom-containing moiety and, in addition, an η2-coordination of another Fe(CO)4 fragment upon the CC bond of the α,β-unsaturated system also results. The complexes were characterised by spectroscopic methods (IR, MS, 1H and 13C NMR) and their structures were confirmed by single-crystal X-ray analysis.

1,2,4-trithioles 2a–e are readily obtained in good yields by dimerization of benzoyldithioacetic acid derivatives using samarium diiodide as a promotor under very mild conditions. The structures of compounds 2a–e were determined by IR, 1H, and 13C NMR spectroscopies using heteronuclear multiple bond correlation, heteronuclear multiple quantum correlation, and nuclear Overhauser enhancement spectroscopy experiments, mass spectrometry, and, in the case of 2a, the structure was confirmed by single-crystal X-ray diffraction studies. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:329–335, 2000

The reaction of aliphatic cyclic ketones with carbon disulfide under basic conditions, followed by an acidic treatment, unexpectedly afforded—in a mild, one-pot reaction—sulfur compounds, such as 1,2-dithiole-3-thiones, 1,3-dithiole-4-thiones, 1,3-dithiin-4-thiones, 1,2,4-trithioles, and dixanthates, instead of the usual conjugated α-oxoketene dithiolic acids. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:120–128, 2000

Syntheses of the heavy chalcogen-containing alumoxanes [(Me)LAl(SeH)]2(μ-O) (4) and ((Me)LAl)2(μ-Te)(μ-O) (7) were accomplished by the reaction of ((Me)LAlH)2(μ-O) (2; (Me)L = HC[(CMe)N(2,4,6-Me3C6H2)]2(-)) with either red selenium or metallic tellurium. The aluminum hydrogenselenide [(Me)LAl(SeH)]2(μ-Se) (3) was also prepared from the reaction of red selenium and (Me)LAlH2 (1). All compounds were characterized by spectroscopic methods and X-ray diffraction studies. Density functional theory calculations were performed on 4 and 7.

The preparation of novel alkali metal chalcogenides supported by multidentate nitrogen rich ligands is reported. Treatment of the ligand precursors [H{(4,5-(P(E)Ph(2))(2)tz}] (E = S (1a), Se (1b)) with organolithium reagents or elemental sodium and potassium in tetrahydrofuran (THF) leads to the isolation of 2-7 in high yields. These compounds were characterized by elemental analysis, IR spectroscopy, mass spectrometry, solution and solid-state multinuclear NMR spectroscopy, and single crystal X-ray diffraction analysis. In the solid state, 2, 4, and 5 are dimers that contain bimetallic six-membered (M(2)N(4)) rings (M = Li, Na). In 3, the discrete monomer [Li{4,5-(P(Se)Ph(2))(2)tz}(thf)(2)] (tz = 1,2,3-triazole) contains a five-membered CPSeLiN ring which adopts an envelope conformation. The polymeric arrangement [K{4,5-(P(S)Ph(2))(2)}tz](infinity) in 6 displays different bonding modes based on the hapticity of the ligand upon binding to the potassium atom. In compounds 2-6, the presence of secondary bonding features the alkali metal chalcogen bonds.

The novel M[(OPPh 2 ) 2 N] 2 .nTHF (M = Sr (2), Ba (3)) complexes were prepared and characterized. Upon exposure to atmospheric oxygen, 2 and 3 were transformed to the dinuclear species Sr 2 -[(OPPh 2 ) 2 N] 4 .2C 3 H 6 O 3 (4) and Ba 2 [(OPPh 2 ) 2 N] 4 .2C 4 H 8 O 3 (5), respectively. Compounds 4 and 5 contain coordinated carboxylic acids obtained from the oxidative degradation of DME and THF, respectively, which were used as solvents for crystallization.

New complexes of the pinch-porphyrin family were obtained from the dimethylester of (proto-, meso-, and deutero-porphyrinato)iron(III) with the ligand [N,N'-bis-pyridin-2-ylmethyl-propane-1,3-diamine] 1-3 and with the ligand [N-pyridin-2-ylmethyl-N'-[3-[(pyridin-2-ylmethyl)-amino]-propyl]-propane-1,3-diamine] 4-6. The UV/VIS studies of 1-6 indicate an increase in the distortion of the ligand field excited state. The 1H NMR spectra of 1-6 at RT and over the range 223-328 K show iron(III)-complexes with quantum mixed spin state (qms) S=5/2, S=3/2. The chemical shifts of the meso protons are consistent with qms state S=3/2, S=5/2, where the S=3/2 spin state is lowest in energy. For methyl-heme the chemical shifts are also consistent with a qms state but now the S=5/2 ground state is lowest in energy. ESR spectra of 1-6 show two different species, B and C, of iron(III) with qms, S=5/2, S=3/2 consistent with the 1H NMR results. Species B with 70% of S=5/2 and species C with 72.5% of S=3/2. The catalytic activity as peroxidase of 1-6 was quantified by guaiacol test; their theoretical maximum rate constants were k(cat) approximately 10(2)-10(3) M(-1) s(-1). A quantitative empirical correlation is found: the higher the 32 spin contribution to the qms state and the higher proportion of this species into the samples, the higher the peroxidase activity. Such a correlation was also obtained for pinch-porphyrins already reported.

The syntheses and molecular structures of [M{N(SePiPr2)2-Se,Se′}2] [M = Sn (2), Se (3)] are described, these complexes consist of discrete, monomeric molecules featuring MSe4 cores that comprise true square-planar geometries.