Recent examples for synthesis of group 4 transition metal (Ti, Zr, Hf) complexes, especially nonbridged half-metallocenes containing anionic donor ligands of the type, Cp′MX 2 (L) (Cp′ = cyclopentadienyl group; M = Ti, Zr, Hf; X = halogen, alkyl etc.; L = anionic donor ligands), as catalysts for precise olefin polymerization have been reviewed. It has been revealed that these complex catalysts displayed unique characteristics especially for ethylene copolymerizations and some examples are known to produce new polyolefins that cannot be prepared by ordinary catalysts such as classical Ziegler–Natta, metallocenes. Modification of both cyclopentadienyl fragment and anionic ancillary donor ligands are the key for precise olefin (co)polymerization.

Nonbridged half-metallocenes containing anionic ancillary donor ligands: New promising candidates as catalysts for precise olefin polymerization

Polynuclear halide complexes of Bi(III): From structural diversity to the new properties

Bismuth chemistry has received much less attention in comparison with that of N, P, As, and Sb, but the last years have revealed an increasing interest in the investigation of both the inorganic and the organometallic chemistry of the heaviest element of the group 15 elements.1 There are several fields Cristian Silvestru (left) was born in Baia-Mare, Romania, in 1955 and graduated in chemistry at the Babes-Bolyai University, Cluj-Napoca, in 1979. He obtained his M.Sc. degree 1 year later. After 2 years as Chemist in a mining company, he was a Research Chemist at the Institute of Chemical and Biochemical Energetics from 1982 to 1989. He received his Ph.D. degree in the group of Professor Ionel Haiduc in Cluj in 1990, with his dissertation research on organometallic compounds with potential biologic activity. In 1990, he joined the Chemistry Department of the BabesBolyai University in Cluj-Napoca. Since 1995 he has been a Full Professor of Inorganic Chemistry and since 1996 Vice-Dean of the Faculty of Chemistry and Engineering Chemistry. He published a book, Organometallics in Cancer Chemotherapy (with I. Haiduc, 2 volumes, CRC Press: Boca Raton, FL, 1989, 1990), and in 1992 received the “Petre Spacu” award of the Romanian Academy for his contributions on the antitumor properties of organometallic compounds (with Dr. Carmen Socaciu and Dr. Adela Bara). Professor Silvestru spent several research stays in Germany (Bremen University 1993sVisiting Professor, 1996sDAAD Grant), Belgium (Vrije Universiteit Brussel 1993sEuropean Community Grant), and Mexico (Instituto de Quimica, Universidad Nacional Autonoma de Mexico 1993−95sVisiting Research Professor, CONACYT Grant). His research interests include organometallic chemistry of main group elements, coordination chemistry of thioligands (mainly organophosphorus compounds), and biological (antitumor) properties of main group organometallics.

Structural chemistry of bismuth compounds. I. Organobismuth derivatives.

Metal complexes with heteroscorpionate ligands based on the bis(pyrazol-1-yl)methane moiety: Catalytic chemistry

We report all-inorganic solar cells based on solution-processed BiI3. Two-electron donor solvents such as tetrahydrofuran and dimethylformamide were found to form adducts with BiI3, which make them highly soluble in these solvents. BiI3 thin films were deposited by spin-coating. Solvent annealing BiI3 thin films at relatively low temperatures (≤100 °C) resulted in increased grain size and crystallographic reorientation of grains within the films. The BiI3 films were stable against oxidation for several months and could withstand several hours of annealing in air at temperatures below 150 °C without degradation. Surface oxidation was found to improve photovoltaic device performance due to the formation of a BiOI layer at the BiI3 surface which facilitated hole extraction. Nonoptimized BiI3 solar cells achieved the highest power conversion efficiencies of 1.0%, demonstrating the potential of BiI3 as a nontoxic, air-stable metal-halide absorber material for photovoltaic applications.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2064&context=chem_pubs

Solution-Processed BiI3 Thin Films for Photovoltaic Applications: Improved Carrier Collection via Solvent Annealing

Polymerization of ethylene by the electrophilic mixed cyclopentadienylpyridylalkoxide complexes [CpM{NC 5 H 4 (CR 2 O)-2}Cl 2 ] (M = Ti, Zr, R = Ph, Pr i )

N-alkoxy-beta-ketoiminate complexes of groups 4 and 5: Synthesis and characterization of the complexes [(eta(5)-C5H4R)M{CH3C(O)CHC(NCH2CHR ' O)CH3}Cl-n] (M = Ti, n = 1; M = Nb, n = 2; R = H, Me; R ' = H, Me), [Ti{CH3C(O)CHC(NCH2CHR ' O)CH3}Cl-2(thf)], and [Ti{CH3C(O)CHC(NCH2CHR ' O)CH3}(2)]

The preparation and X-ray crystal structures of the bismuth trihalide−THF (THF = tetrahydrofuran) adducts [BiBr3(THF)3] and [BiCl3(THF)2] are described together with an X-ray powder diffraction derived structure of BiI3.

Tetrahydrofuran Adducts of Bismuth Trichloride and Bismuth Tribromide

The reactions between either BiBr2Ph and Na/K[Mo(CO)3(ηC5H5)], [BiPh{Mo(CO)3(ηC5H5)}2] and BiBr2Ph, or BiBr3 and BiPh3 and [Bi{Mo(CO)3(ηC5H5)}3] afford the complex [BiBrPh{Mo(CO)3(ηC5H5)}] 1 which has been characterised by X-ray crystallography. Complex 1 comprises a bismuth centre bonded to a bromine atom, a phenyl group and a Mo(CO)3(ηC5H5) fragment together with a longer secondary intermolecular interaction between a bromine from an adjacent molecule which results in a one-dimensional polymeric structure. Addition of a source of bromide anion to 1 affords the anionic complex [BiBr2Ph{Mo(CO)3(ηC5H5)}]−3− although prolonged reaction results in the complex [BiBr2{Mo(CO)3(ηC5H5)}2]−5− which was characterised by X-ray crystallography as its [Ph4P]+ salt. Complex 5− comprises a mononuclear bismuth centre bonded to two bromine atoms and two Mo(CO)3(ηC5H5) fragments in a geometry which lies between equatorially vacant trigonal bipyramidal and tetrahedral. The complex [PPN]2[Bi2Cl6{Mo(CO)3(ηC5H5)}2] 8 has also been synthesised and characterised by X-ray crystallography. A dimeric dianion is observed which can be viewed as two edge-shared square-based pyramids with chlorine atoms in the basal planes and Mo(CO)3(ηC5H5) fragments in the apical positions on opposite sides of the Bi2Cl6 plane.



Untersuchungen zur Synthese und Struktur von Organomolybdan-Bismuthalogenid-Komplexen



Die Reaktionen von BiBr2Ph mit Na/K[Mo(CO)3(ηC5H5)], von [BiPh{Mo(CO)3(ηC5H5)}2] mit BiBr2Ph oder BiBr3 und BiPh3 mit [Bi{Mo(CO)3(ηC5H5)}3] ergeben den Komplex [BiBrPh{Mo(CO)3(ηC5H5)}] 1, der rontgenographisch charakterisiert worden ist. Der Komplex 1 besteht aus einem Bismutzentrum mit einem Bromatom, einer Phenylgruppe und einer Mo(CO)3(ηC5H5)-Einheit. Eine intermolekulare Wechselwirkung besteht zum Bromatom eines benachbarten Molekuls, wodurch sich eine eindimensionale polymere Struktur ergibt. Bei der Umsetzung mit einer Bromidabgebenden Verbindung wird zunachst der anionische Komplex [BiBr2Ph{Mo(CO)3(ηC5H5)}2]−3− und bei langerer Reaktion [BiBr2{Mo(CO)3(ηC5H5)}2]−5− gebildet, das als [Ph4P]+-Salz rontgenographisch charakterisiert wurde. Der Komplex 5−, der am Bi zwei Br und zwei Mo(CO)3(ηC5H5)-Einheiten enthalt, liegt in einer Struktur zwischen unvollstandig trigonal-pyramidal und tetraedrisch vor. Der Komplex [PPN]2[Bi2Cl6{Mo(CO)3(ηC5H5)}2] 8 wurde ebenfalls dargestellt und rontgenographisch charakterisiert. Es liegt ein dimeres Anion vor, das aus zwei quadratischen Pyramiden mit einer gemeinsamen Kante besteht, in denen die Chloratome in der Basisebene und die zwei Mo(CO)3(ηC5H5)-Einheiten sich an den Spitzen in gegenuberliegenden Positionen befinden.

Synthetic and structural studies on organomolybdenum-bismuth halide complexes

Structures of known isopolyoxotungstates are reviewed and an approach to their synthesis from tungsten oxoalkoxides WO(OR)4 is described. Crystal structures of the tetraalkylammonium tungstates Q2WO4.H2O [Q+ = Me4N+ or Me3(PhCH2)N+] have been determined and show the anions to be hydrogen bonded to water molecules in extended chains. Reactions between Q2WO4 and WO(OMe)4 yield the binuclear anions [W2O5(OMe)4]2- via rapid ligand redistribution, and hydrolysis of the tetrabutylammonium salt produces a new isopolytungstate characterised by its 5-line 183W NMR spectrum. This compound is reactive towards CH2Cl2 and MeNO2, producing tetranuclear species in each case. The synthesis and non-aqueous reactivity of (Bun 4N)6[H2W12O40] have also been investigated. Mo6O19 2- reacts with RNCO to give organoimido substituted [Mo6(NR)O18]2- (R = C6H4Me-4 or Bu′) and the crystal structure of the tert-butylimido compound is reported.

R. J. Errington

Papers

Polymerization of ethylene by the electrophilic mixed cyclopentadienylpyridylalkoxide complexes [CpM{NC 5 H 4 (CR 2 O)-2}Cl 2 ] (M = Ti, Zr, R = Ph, Pr i )

N-alkoxy-beta-ketoiminate complexes of groups 4 and 5: Synthesis and characterization of the complexes [(eta(5)-C5H4R)M{CH3C(O)CHC(NCH2CHR ' O)CH3}Cl-n] (M = Ti, n = 1; M = Nb, n = 2; R = H, Me; R ' = H, Me), [Ti{CH3C(O)CHC(NCH2CHR ' O)CH3}Cl-2(thf)], and [Ti{CH3C(O)CHC(NCH2CHR ' O)CH3}(2)]

Tetrahydrofuran Adducts of Bismuth Trichloride and Bismuth Tribromide

Synthetic and structural studies on organomolybdenum-bismuth halide complexes

New Aspects of Non-Aqueous Polyoxometalate Chemistry