Seven new organoammonium 1,3-dimethylviolurates [R1R2R3NH][1,3-Me2Vio] R1 = R2 = H, R3 = t Bu (3), R3 = Cy (cyclohexyl) (4), R3 = Ad (adamantyl) (5), R3 = C6H2Me2-4,5-NH2-2 (6); R1 = H, R2 = R3 = Et (7), i Pr (8); R1 = H, R2 + R3 = (-CH2-)4 (9) have been prepared by treatment of 1,3-dimethylvioluric acid (2, = HMe2Vio) with different primary and secondary amines. All violurate salts form bright blue or red/purple, nicely crystalline solids. The compounds have been characterized by their solid-state IR and solution NMR (1H, 13C) and UV-spectroscopic data as well as elemental analyses. Structure determinations by single-crystal X-ray diffraction of compounds 4, 7 and 9 revealed supramolecular self-assembly into different one-dimensional substructures through cation-anion N-H & ctdot;N and N-H & ctdot;O hydrogen bonds. In addition, the molecular and crystal structure of anhydrous 1,3-dimethylvioluric acid (2) has also been determined.

AbstractKarl‐Heinz Thiele war ein Wegbereiter der modernen metallorganischen Chemie und ein mitreißender Hochschullehrer.

The reactivity of the stable N-heterocyclic nitrenium salt 1,3-dimethyl-1,2,3-benzotriazolium iodide (1) toward various nucleophilic reagents has been investigated. Strongly nucleophilic reagents such as potassium hydride (KH), potassium cyclopentadienide (KCp), potassium tert-butoxide ((KOBu)-Bu-t), sodium methoxide (NaOMe), and sodium ethanethiolate (NaSEt) all reacted with 1 under demethylation and back-formation of 1-methyl-1,2,3-benzotriazole (2) in high isolated yield (ca. 80-90%). In marked contrast, an unusual phosphide addition reaction took place when 1 was treated with 1 equiv. of potassium diphenylphosphide (as the 1,4-dioxane adduct KPPh2(dioxane)(2)). In the course of this reaction the P atom replaces the central nitrogen of the triazole ring while being formally oxidized to an iminophosphorane derivative (3). Both compounds 2 and 3 have been structurally characterized through single-crystal X-ray diffraction.

The reaction of Cu(NO3)(2)3H(2)O with a potentially bidentate P,N-donor ligand, diphenyl-2-pyridylphosphine (PPh2Py), in 1:2 molar ratio resulted in formation of a kappa N-2,O-chelated complex, [Cu(kappa N-2,O-P(O)Ph2Py)(2)(NO3)(2)] (1). A single-crystal X-ray study confirmed the formation of a five-membered kappa N-2, O-chelate involving pyridyl nitrogen and phosphine oxide oxygen donor sites. A DFT study was carried out on 1 to understand the chelate ring expansion process upon oxidation with PPh2Py. DFT analysis revealed that 1 contains a relatively strong M-N bond compared to its M-P bond, facilitating the oxidation of the P atom followed by chelate ring expansion.

In this contribution, the first amidinate and amidine derivatives of p-carborane are described. Double lithiation of p-carborane (1) with n-butyllithium followed by treatment with 1,3-diorganocarbodiimides, R–N=C=N–R (R = iPr, Cy (= cyclohexyl)), in DME or THF afforded the new p-carboranylamidinate salts p-C2H10B10[C(NiPr)2Li(DME)]2 (2) and p-C2H10B10[C(NCy)2Li(THF)2]2 (3). Subsequent treatment of 2 and 3 with 2 equiv. of chlorotrimethylsilane (Me3SiCl) provided the silylated neutral bis(amidine) derivatives p-C2H10B10[C{iPrN(SiMe3)}(=NiPr)]2 (4) and p-C2H10B10[C{CyN(SiMe3)}(=NCy)]2 (5). The new compounds 3 and 4 have been structurally characterized by single-crystal X-ray diffraction. The lithium carboranylamidinate 3 comprises a rare trigonal planar coordination geometry around the lithium ions.

The current library of amidinate ligands has been extended by the synthesis of two novel dimethylamino-substituted alkynylamidinate anions of the composition [Me2N-CH2-C C-C(NR)(2)](-)(R = Pr-i, cyclohexyl (Cy)). The unsolvated lithium derivatives Li[Me2N-CH2-C C-C(NR)(2)] (1: R - Pr-i, 2: R - Cy) were obtained in good yields by treatment of in situ-prepared Me2N-CH2-C C-Li with the respective carbodiimides, R-N-C-N-R. Recrystallization of 1 and 2 from THF afforded the crystalline THF adducts Li[Me2N-CH2-C C-C(NR)(2)]center dot nTHF (1 a: R = Pr-i, n = 1; 2a: R = Cy, n = 1.5). Precursor 2 was subsequently used to study initial complexation reactions with selected diand trivalent transition metals. The dark red homoleptic vanadium(III) tris(alkynylamidinate) complex V-[Me2N-CH2-C C-C(NCy)(2)](3) (3) was prepared by reaction of VCl3(THF)(3) with 3 equiv. of 2 (75% yield). A salt-metathesis reaction of 2 with anhydrous FeCl, in a molar ratio of 2:1 afforded the dinuclear homoleptic iron(II) alkynylamidinate complex Fe-2[Me2N-CH2-C C-C(NCy)(2)](4) (4) in 69 2 :6 isolated yield. Similarly, treatment of Mo-2(OAc)(4) with 3 or 4 equiv. of 2 provided the dinuclear, heteroleptic molybdenum(II) amidinate complex Mo-2(OAc)[Me2N-CH2C C-C(NCy)(2)](3) (5; yellow crystals, 50 2 :6 isolated yield). The cyclohexyl-substituted title compounds 2a, 4, and 5 were structurally characterized through single-crystal X-ray diffraction studies.

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 quality measures.

The syntheses of the new ligands 3-(pyrazol-1-yl)methylpropanoate (L1) and 3-(2,4-dimethylpyrazol-1-yl)methylpropanoate (L2) and their complexation with palladium(II) have been investigated. In our hands L1 is best prepared by a Michael addition catalyzed by Cs2CO3 and L2 by a catalyst- and solvent-free reaction. Both L1 and L2 react with PdCl2(COD) to produce trans-PdCl2(L1)(2) (3) and trans-PdCl2(L2)2 (4) respectively. The crystal structures of both new complexes have been determined. An isomerization has been observed when complex 4 is dissolved in CDCl3 or CD3CN. Kinetic data indicate that this is an equilibrium that is first order in both directions. We suggest this may be due to the isomerization of the trans- to the cis-isomer. Their ease of preparation in nearly quantitative yields make the new ligands L1 and L2 potentially useful for further studies.

A series of new alkynylamidinate complexes of selected first and second row transition metals has been synthesized and fully characterized. Treatment of MCl2 precursors (M=Mn, Fe, Co) with 2 equiv. of the lithium alkynylamidinates Li[c-C3H5-C equivalent to C-C(NR ')(2)] . THF (R ' = Pr-i (2), Cy (cyclohexyl) (2)) afforded a series of binuclear complexes of the type M-2[c-C3H5-C equivalent to C-C(NR)(2)-kappa N:kappa N '](2)[c-C3H5-C equivalent to C-C(NR)(2)-kappa N-2,N '](2) (3: M = Mn, R = Cy; 4 a: M = Fe, R = Pr-i; 4 b: M = Fe, R = Cy; 5: M = Co, R = Pr-i) with no significant metal-metal bonding. In marked contrast, a similar reaction of CrCl2 with 2 equiv. of 1 afforded the homoleptic dinuclear chromium(II) complex Cr-2[c-C3H5-C equivalent to C-C((NPr)-Pr-i)(2)-kappa N:kappa N '](4) (6) which supposedly comprises a Cr-Cr quadruple bond. Complex 6 could also be prepared in a more rational way and in better yield (61 %) by using dichromium(II) tetraacetate, Cr-2(OAc)(4), as starting material. Related reactions employing dimolybdenum(II) tetraacetate, Mo-2(OAc)(4), and 2 or 3 equiv. of 1 afforded the mixed-ligand paddle wheel-type complexes trans-Mo-2(OAc-kappa O:kappa O ')(2)([c-C3H5-C equivalent to C-C((NPr)-Pr-i)(2)-kappa N:kappa N '](2) (7) and Mo-2(OAc-kappa O:kappa O ')([c-C3H5-C equivalent to C-C((NPr)-Pr-i)(2)-kappa N:kappa N '](3) (8). All title compounds were structurally characterized through single-crystal X-ray diffraction and spectroscopic techniques (NMR, IR, Raman).

A series of brightly colored alkaline earth metal 1,3-dimethylviolurates M(Me2Vio)2 have been prepared and fully characterized. The title compounds AE(Me2Vio)2·nH2O (AE = Mg, n = 6 (3); AE = Ca, n = 8 (4), AE = Sr, n = 6 (5); AE = Ba, n = 4 (6)) were obtained by neutralizing 1,3-dimethylvioluric acid monohydrate (=H(Me2Vio)·H2O; 2) with 0.5 equiv. of the corresponding metal dihydroxides AE(OH)2. The hair-like appearance of the Sr derivative 5 prevented the growth of single-crystals. This problem could be solved by crystallizing the crown ether derivative Sr(Me2Vio)2(18-crown-6) (5a). The isolated salts exhibit intense colors ranging from red to purple. Various attempts to prepare the beryllium derivative Be(Me2Vio)2 failed. Instead, work-up of the reaction mixtures provided pink crystals of a new modification of 2 formulated as [H3O][Me2Vio] (2b) as shown by an X-ray diffraction study. An unexpected oxidation reaction of the barium salt Ba(Me2Vio)2 led to formation of the novel mixed-anion salt Ba(Me2Vio)(Me2NO2Barb)·2H2O (8, Me2NO2Barb- = 1,3-dimethyl-5-nitrobarbiturate anion). Compound 8 could also be synthesized deliberately by treatment of Ba(OH)2 with a 1 : 1 mixture of 2 and 1,3-dimethyl-5-nitrobarbituric acid (7, =H(Me2NO2Barb)·H2O). All new compounds were fully characterized by their IR, Raman, NMR (1H, 13C{1H}) and UV-vis spectra as well as elemental analyses. Single-crystal X-ray diffraction studies revealed that the solid-state structures of compounds 3, 4, 5a and 6 are governed by the typical coordination behavior of the alkaline-earth metals, i.e. increasing coordination numbers and a decreasing degree of hydration when going from Mg to Ba. The dimensions of the structures range from hydrogen-bonded ions (3) over monomeric, neutral complex molecules (4, 5a), to polymeric networks (6). The successful isolation of the mixed-anion barium salt 8 adds a new facet to the coordination chemistry of violurate and related ligands.

A series of new homoleptic first-row transition metal and yttrium tris(alkynylamidinate) complexes have been synthesized and fully characterized. The starting materials [c-C3H5-C equivalent to C-C(NR)(2)]Li.THF (1: R=Pr-i, 2: R=Cy; Cy=Cyclohexyl) were obtained in high yields by employing a modified literature procedure. In the course of this study, the unprecedented tetrameric, unsolvated lithium amidinate [Li{c-C3H5-C equivalent to C-C((NPr)-Pr-i)(2)}](4) (1 a) could be isolated and structurally characterized. In addition to the Li salts, two new potassium cyclopropylethinylamidinates, K[c-C3H5-C equivalent to C-C(NR)2].THF (3: R=Pr-i, 4: R=Cy) were prepared by nucleophilic addition of potassium cyclopropylacetylide to N,N '-di-iso-propylcarbodiimide or N,N '-dicyclohexylcarbodiimide. The new homoleptic first-row transition metal and yttrium complexes M[c-C3H5-C equivalent to C-C((NPr)-Pr-i)(2)](3) (M=Y (5), Cr (6), Fe (7)) and M[c-C3H5-C equivalent to C-C(NCy)(2)](3) (M=Y (8), Ti (9), V (10), Cr (11), Fe (12)) were found to be readily available by treatment of MCl3 precursors with 3 equiv. of the alkali metal cyclopropylethinylamidinates. An alternative synthetic route to the titanium(III) complex 9 was found in the reaction of trichloro(cyclopentadienyl)titanium(IV) and lithium amidinate 2 in a 1 : 3 molar ratio. Compounds 5-12 were fully characterized by the usual set of analytical and spectroscopic methods as well as single-crystal X-ray diffraction studies. All eight complexes represent unsolvated, homoleptic metal(III) tris(amidinates).

The synthesis and structural characterization of Ae(TpiPr2)2 (Ae = Mg, Ca, Sr, Ba; TpiPr2 = hydrido-tris(3,5-diisopropyl-pyrazol-1-yl)borate) are reported. In the crystalline state, the alkaline earth metal centers are six-coordinate, even the small Mg2+ ion, with two κ3-N,N',N''-TpiPr2 ligands, disposed in a bent arrangement (B···Ae···B < 180°). However, contrary to the analogous Ln(TpiPr2)2 (Ln = Sm, Eu, Tm, Yb) compounds, which all exhibit a bent-metallocene structure close to Cs symmetry, the Ae(TpiPr2)2 compounds exhibit a greater structural variation. The smallest Mg(TpiPr2)2 has crystallographically imposed C2 symmetry, requiring both bending and twisting of the two TpiPr2 ligands, while with the similarly sized Ca2+ and Sr2+, the structures are back toward the bent-metallocene Cs symmetry. Despite the structural variations, the B···M···B bending angle follows a linear size-dependence for all divalent metal ions going from Mg2+ to Sm2+, decreasing with increasing metal ion size. The complex of the largest metal ion, Ba2+, forms an almost linear structure, B···Ba···B 167.5°. However, the "linearity" is not due to the compound approaching the linear metallocene-like geometry, but is the result of the pyrazolyl groups significantly tipping toward the metal center, approaching "side-on" coordination. An attempt to rationalize the observed structural variations is made.

A complete series of alkali metal 1,3‐dimethylviolurates M(Me2Vio) was synthesized and fully characterized. The title compounds M(Me2Vio)(H2O) [M = Li (3), Na (4)], K(Me2Vio)(H2O)0.5 (5) and M(Me2Vio) [M = Rb (6), Cs (7)] were prepared by neutralizing 1,3‐dimethylvioluric acid (= HMe2Vio; 2) with 1 equiv. of the corresponding metal hydroxides MOH. The resulting salts exhibit striking colors ranging from orange‐red (3) through purple (4, 5) to bright blue (6, 7). In contrast to the monohydrate 4, the classical synthesis of sodium 1,3‐dimethylviolurate from 1,3‐dimethylbarbituric acid and NaNO2 afforded the purple trihydrate Na(Me2Vio)(H2O)3 (4a). All new compounds have been fully characterized by their IR and NMR (1H, 13C) spectra as well as elemental analyses. X‐ray crystal structure determination revealed that the title compounds exist as one‐ (Li, Na), two‐ (K, Cs), or three‐dimensional (Rb) coordination polymers in the solid state.

The new PPA ligands 3-[5-methyl-3-(trifluoromethyl)-1H-pyrazol-1-yl]propanamide (CF(3)MePPA;3) and 3-[3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl]propanamide ((CF3)(2)PPA;4) were synthesized by Aza-Michaeladdition of the specific pyrazole derivatives to acrylamide. Both products were characterized by elemental analyses, IR and NMR spectroscopy, and mass spectrometry. X-Ray structure determination of3revealed the presence of a one-dimensional hydrogen-bonded structure in the solid state. The ligating ability of the new ligands towards PdCl(2)was studied, showing that3behaves similar to Me(2)PPA and reacts cleanly with PdCl(2)to afford the sparingly soluble complex PdCl2(CF(3)MePPA-kappa N)(2). By contrast, the donor ability of pyrazolyl group in4was found to be considerably reduced, thus resulting in the formation of the unusual complex PdCl2{(CF3)(2)PPA-kappa N}{(CF3)(2)PPA-kappa O}.

The first rubidium and cesium enediamide complexes based on bulky 1,4-diaza-1,3-diene ligands (DADs) have been prepared by metalation of either 1,4-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (1, = H2DADDipp) or 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene (2, = Me2DADDipp) with an excess of Rb or Cs metals in coordinating solvents such as tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME). All new complexes were fully characterized by spectroscopic and analytical methods as well as single-crystal X-ray diffraction studies.

This review summarizes the progress in organo-f-element chemistry during the year 2018. A continuing trend for many years, which remained important in 2018, was the synthesis and investigation of reactive trivalent lanthanide mono- and bis(alkyl) or (benzyl) complexes supported by a variety of non-cyclopentadienyl ligands such as amidinates, beta-diketiminates or NHC ligands. An important contribution was the synthesis of the homoleptic, solvent-free dibenzyl complexes [Ln(CH2Ph)(2)](n) (Ln = Eu, Sm, Yb) which served as precursors for the synthesis of the first divalent lanthanide imides [(THF)Ln(mu(3)-NDipp)](4). Lanthanide carbene chemistry has also been of growing interest. Functionalized NHC ligands were employed to unveil new reactivity as demonstrated in the synthesis of homoleptic lanthanide complexes with aryloxide-tethered NHC ligands, Ln(L-R)(3) (L-R = 2-0-3,5-(Bu2C6H2)-Bu-t(1-C{N(CH)(2)N(R)}), R = Pr-i, Bu-t, Mes), which reacted with CO2 by selective insertion into Ln-C(NHC) bonds. A diverse reactivity towards small unsaturated molecules was observed for phosphino and thiophosphinoyl alkylidene lanthanide complexes as well as for phosphinidene lanthanide complexes. Furthermore, the trinuclear mixed oxo/alkyl complexes L(3)(1)Ln(3)(mu(2)-CH3)(3)(mu(3)-CH3)(mu(3)-0) (with L-1 = PhC((NC6H3Pr2)-Pr-i-2,6)(2); Ln = Sc, Y, Lu, Dy) undergo non-redox oxygen transfer with PhNCS or CS2 despite the presence of reactive Ln-alkyl bonds. The synthesis of pseudo-Grignard reagents PhLnl (Ln = Eu, Yb) was investigated and their synthetic potential in organometallic chemistry demonstrated. The first lanthanide-cyclobutadienyl complexes were obtained as anionic "tuck-in" complexes [M{eta(4)-C-4(SiMe3)(4)}{eta(4)-C-4(SiMe3)(3)-kappa-(CH2SiMe2)}](2-) (Ln = Y, Dy), showing square-shaped cyclobutadienyl ligands. Further progress has been made in the understanding of "new" divalent lanthanide chemistry, especially the influence of the ligand size. The small Cele ligand formed highly reactive complexes, e.g.[K(crypt)][Y(Cp-me)(3)], with the larger lanthanides, which reacted with the solvent to give unprecedented reductive THE-ring opening. However, with smaller lanthanides the complexes [(18-crown-6)K(mu-Cp-Me)K(18-crown-6)][Cp(3)(Me)Ln] (Ln = Tb, Ho), displaying an inverse sandwich as counter cation, could be isolated. The reactivity of the highly bulky complex SmCp2Ar-Et (cp(Ar-Et) = C-5(4-EtC6H4)(5)) towards a large range of small molecules was investigated, revealing only reaction with cuminil to afford the first trivalent lanthanide decaaryllanthanidocene complex SmCp2Ar-Et(Ar'C(O)C(O)Ar') (Ar' = 4-iPrC(6)H(4)). Following the important discovery of recent years on SMM (single molecule magnet) behavior of Dy metallocenes, the quest for even better SMMs continued in 2018. Several new record-holding complexes were synthesized based on polyisopropyl-cyclopentadienyl complexes, with the best complex to date being [((C5Pr5)-Pr-i)(C5Me5)Dy] [BAr4], showing magnetic hysteresis up to 80 K and an effective energy barrier to reversal of magnetization U-eff =1541 cm(-1). Several remarkable lanthanide arene complexes have been prepared and structurally characterized. For example, the bimetallic inverse sandwich La2+ complex salt [K(18-crown-6)(THF)(2)][(Cp '' La-2)(2)(mu-eta(6):eta(C6H6)-C-6)]center dot THF (Cp '' = C5H3(SiMe3)(2)-1,3) reduces hydrocarbons such as naphthalene, anthracene, or cyclooctatetraene to give La3+ complexes of the hydrocarbon anions. Samarium-arene bonding has also been observed in the rare samarium(II) aryloxide Sm(OAripr6)(2) [Ar-ipr6 = -C6H3-2,6-(C6H2-2,4,6-Pr-i(3))(2)] and in the remarkable tetranuclear samarium(II) inverse sandwich complex (mu-eta(6):eta(6)-C7H8)[KSmL3](2) (L= OSi ((OBu)-Bu-t)(3)). Several new triple-decker complexes of the type Ln(2)(COT '')(3) (COT '' = bis(trimethylsilyl)cycloocta tetraenyl dianion) have been isolated and structurally characterized. The synthesis and structural characterization of four unsolvated divalent lanthanide cyclononatetraenyl sandwich complexes, Ln(Cnt)(2) (Ln = Sm, Eu, Tm, Yb; Cnt =eta(9)-cyclononatetraenyl) have also been achieved. Single-crystal X-ray diffraction studies revealed that these neutral sandwich complexes are rigorously linear. A rare hetero-bimetallic [1] ferrocenophane terbium(III) complex has been found to exhibit single-ion magnet behavior. Reduction of the scandium precursor Sc(nacnac)(OAr)(OCP) (nacnac(-) = [ArNC(CH3)](2)CH, Ar = 2,6-(Pr2C8H3)-Pr-i) with KC8 afforded a binuclear scandium complex comprising a unique [OCPPCO](4-) central motif formed through P-P radical coupling. Heterobimetallic Sm/Co polyarsenides [((CpCo)-Co-ttt)(2)As4Sm (C5Me4R)(2)] (Cp-ttt = 1,2,4-(C5H2Bu3)-Bu-t, R = Me, Pr-n) were synthesized from the reaction of divalent Sm complexes Cp*Sm-2, Cp*Sm-2(THF)(2) or ((C5Me4Pr)-Pr-n)(2)Sm with [((CPCo)-Co-ttt)(2)(mu eta As-2:2(2))(2)], while the Sm/Sb multi metallic complex [(Cp*Sm-2)(4)(mu(4),eta(2:2:2:2)-Sb-8)] was synthesized from the oxidation of Cp*Sm-2 with activated antimony. The chemistry of endohedral lanthanide metallofullerenes continued to be an active field of research in 2018. Significant achievements have also been made in the area of organolanthanide catalysis. For example, a variety of highly active lanthanide catalysts for the polymerization of polar substituted styrene monomers as well as the polymerization of 2-vinylpyridine have been developed. Half sandwich complexes of scandium have been successfully employed in the copolymerization of myrcene with ethylene and propylene. New organolanthanide-catalyzed reactions include the diastereo- and enantioselective C(sp)-H addition of terminal alkynes to 3,3-substituted cyclopropenes and the catalytic hydrothiomethylation of olefins and dienes with a series of methyl-alkyl sulfides. Moreover, the first-time scandium-catalyzed C(sp(3))-H alkylation of N,N-dimethyl anilines with olefins has been investigated. Significantly less results over previous years have been published in 2018 on the use of organolanthanide precursors in materials science. The synthesis and reactivity of complexes with actinide-element multiple bonds, e.g. Ac=C, Ac=N, Ac=P, is a highly active research area. The synthesis of uranium(IV) silyl-phosphino-carbene complexes was reported, among which the bis(carbene) complex [U{C(SiMe3)(PPh2)}(BIMPTms)(mu-Cl)Li(TMEDA)(mu-TMEDA)(0.5)](2) (36%) showing a 3-center U-C-P character and a short U=C-carbene bond. A rare U(IV) imido species [K(THF)(3)][(PN)U(NH)((Pr2P)-Pr-i(C8H3Me)N(C8H2Me2CH2)] was isolated, in which one of the PN ligands has been cyclometallated. This complex was proposed to have been formed by the addition of the ligand C -H of a nearby methyl group to a uranium nitride intermediate. The synthesis and the diverse reactivity of the first base-free terminal phosphinidene thorium(IV) complex, Th(Cp-3(tBu))(2)(PR), towards heterounsaturated small molecules was reported. The functionalization of CO and tert-butyl nitrile have been reported for a Th(IV) bis(phosphido) complex, (C8Me5)(2)Th{P(Mes)(H)}(2). involving intramolecular proton transfer reactions. The synthesis and characterization of the first Np(II) organometallic complex [K(crypt)][Np (Cp '')(3)] (crypt = 2,2,2-cryptand, Cp '' = C5H3(SiMe3)(2)) was achieved by reduction of a trivalent precursor. The synthesis and characterization of a neutral U(II) complex, U(NHAri(Pr6))(2), and the very reactive uranium(III) cation [U(NHAriPr6)(2)][BArF24] supported by an amido bis(arene) ligand was reported. Good progress has been made in metallofullerene chemistry of the actinides, as evidenced by the structural characterization of the dimetallic actinide endohedral metallofullerene (EMF) U-2@C-80, revealing short U-U bonding inside the cage. Actinide complexes have also found new applications in catalysis, as shown by the first example of selective hydroboration of aldehydes and ketones using actinide catalysis. (C) 2019 Published by Elsevier B.V.

New alkali metal (M = Li, Na, K) enediamide complexes derived from 1,4-diaza-1,3-dienes (= DADs) have been synthesized and structurally characterized. The complexes were prepared by direct metalation of either 1,4-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (1, = (H2)DAD(Dipp)) or 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene (2, = (Me2)DAD(Dipp)) with an excess of the respective alkali metals in donor solvents such as THF or DME. All new complexes were fully characterized by spectroscopic methods and X-ray crystallography.

Nine new organoammonium violurates [R1R2R3NH][C4H2N3O4] [R1 = R2 = H, R3 = c‐C3H5 (2), R3 = tBu (3), R3 = adamantyl (4), R3 = C6H2Me2‐4,5‐NH2‐2 (5); R1 = H, R2 = R3 = Et (6), iPr (7); R1 = H, R2/R3 = (–CH2–)4 (8); R1 = R2 = R3 = Et (9); R1 = R2 = Me, R3 = (CH2)2NMe2 (10)] were prepared by treatment of violuric acid (1) with a variety of primary, secondary, and tertiary amines. With the exception of orange 5, all these violurate salts form bright blue or blue‐purple crystalline solids. The acidic triethylammonium violurate [NHEt3]H[C4H2N3O4]2·H2O (9a) was isolated in the form of red‐violet, plate‐like crystals by the reaction of violuric acid hydrate with triethylamine in a molar ratio of 2:1 in ethanol. All compounds were fully characterized by their IR and NMR (1H, 13C) data as well as elemental analyses. X‐ray crystal structures determinations of 2, 7, and 9a revealed supramolecular self‐assembly through networks of N–H···N and N–H···O hydrogen bonds in the crystalline state.

Bis(demethoxy)curcumin (BDMC), extracted from rhizomes of the traditional herb Curcuma longa, has revealed a wide range of medicinal applications, such as antimicrobial and anticarcinogenic. Pure BDMC was obtained by recrystallization from ethanol and three BDMC solvates were identified with acetone, methanol, and isopropanol. The crystal structures of pure BDMC and the solvates were resolved by single crystal X-ray diffraction. Analyses of the crystal structures and calculations of crystal packing efficiencies revealed that pure BDMC is efficiently packed. The solvents involved are not utilized to fill the void spaces in the crystal structures, but to provide effective intermolecular interactions. The stoichiometry of the three solvates obtained from single crystal data is 1:1, which is in good agreement with the gravimetric analyses. Furthermore, the desolvation process and the stability of the solvates were investigated by various analytical techniques including X-ray diffraction, differential scanning calorimetry, thermogravimetric analyses, hot-stage microscopy, and dynamic vapor sorption. Results show that the methanol solvate is more stable compared to the acetone and isopropanol solvates attributed to the strong hydrogen bonding network. Moreover, the desolvation process of the three solvates proceeds through a destructive-reconstructive mechanism.

The reaction of potassium carbonate with elemental sulfur or selenium in acetone in the presence of [PPN]Cl (PPN = (Ph3P)2N) produces catena-[S12]2-, the longest structurally characterised polysulfide dianion, or spiro-[Se11]2- as ion-separated [PPN]+ salts.