showing 9 related works from this author
Redox-induced coordination isomerization of a phosphoniobenzophospholide.
2003
1-Triphenylphosphoniobenzo[c]phospholide 1 reacts with [M(CO)(5)Br] (M = Mn, Re) and [Mn(CO)(3)(naphthalene)][BF(4)] to give complexes cis-[M(CO)(4)(1)Br] (5 a,b) and [Mn(CO)(3)(1)][BF(4)] (6 a[BF(4)]), respectively, featuring eta(1)(P)- and eta(5)(pi)-coordination of the phosphole ring. The corresponding reactions with [M(2)(CO)(10)] proceed with conservation of the metal-metal bond and yield, depending on the reaction temperature, dinuclear complexes [M(2)(CO)(8)(1)] (M=Mn, 7 a) or [M(2)(CO)(6)(1)(2)] (M=Mn, Re, 8 a,b) with mu(2)-bridging eta(1)(P):eta(2)(Pdbond;C) coordination of the phosphole moiety. All complexes formed were characterized by spectroscopic data; 5 b, 6 a[BF(4)], and 8 a…
Anorganische Chemie 2002
2003
In der anorganischen Molekulchemie sind Mehrfachbindungssysteme, Kationen und „stabile” Radikale wieder starker ins Rampenlicht geruckt. Aktivierung kleiner Molekule und Sensorik mit Metallkomplexen sind zwei Forschungsschwerpunkte der Koordinationschemie. Die Suche nach biomimetischen Modellverbindungen geht weiter; Taktgeber des Fortschritts in der Bioanorganischen Chemie ist weiterhin die Proteinkristallographie.
Ambident PCN Heterocycles: N- and P-Phosphanylation of Lithium 1,3-Benzazaphospholides
2009
Synthetic and structural aspects of the phosphanylation of 1,3-benzazaphospholides 1(Li), ambident benzofused azaphosphacyclopentadienides, are presented. The unusual properties of phospholyl-1,3,2-diazaphospholes inspired us to study the coupling of 1(Li) with chlorodiazaphospholene 2, which led to the N-substituted product 3. Reaction of 1(Li) with chlorodiphenyl- and chlorodicyclohexylphosphane likewise gave N-phosphanylbenzazaphospholes 4 and 5, whereas with the more bulky di-tert-butyl- and di-1-adamantylchlorophosphanes, the diphosphanes 6 and 7 are obtained; in the case of 7 they are isolated as a dimeric LiCl(THF) adduct. Structural information was provided by single-crystal X-ray d…
Template-controlled assembly of ditopic catechol phosphines: a strategy for the generation of complexes of bidentate phosphines with different bite a…
2008
A rational approach to the synthesis of heterobi- or -trimetallic complexes based upon self-assembly of a flexible ditopic catechol-phosphine ligand with [(cod)PdCl(2)] and simple metal halides such as GaCl(3), BiCl(3), SnCl(4), or ZrCl(4) is described. All products were characterized by spectroscopic and analytical data and single-crystal X-ray diffraction studies. The molecular structures can be described in terms of cis-configured palladium complexes with supramolecular bisphosphine ligands that are formed by the assembly of two phosphine catecholate fragments on a main group/transition metal template. Of particular interest are the distinct decreases in P-Pd-P bite angles and P...P dist…
N-Heterocyclic Phosphenium, Arsenium, and Stibenium Ions as Ligands in Transition Metal Complexes: A Comparative Experimental and Computational Study
2005
Reaction of 2-chloro-1,3,2-diazaarsolenes and -diazaphospholenes with Tl[Co(CO)4] gives instable complexes of type [Co(ER2)(CO)4] which decarbonylated to yield [Co(ER2)(CO)3]. Spectroscopic and X-ray diffraction studies revealed that the tetracarbonyl complexes can be formulated as ion pair for E = P and as covalent metalla-arsine for E = As, and the tricarbonyl complexes as carbene-like species with a formal E=Co double bond. A similar reactivity towards Tl[Co(CO)4] was also inferred for 1,3,2-diazastibolenes although the products were not isolable and their constitution remained uncertain. Evaluation of structural and computational data suggests that the weak and polarized Co–As bond in […
Ambident Reactivity of P˭CH‒N‒Heterocycles: Lithiation and Substitution Sites
2011
Abstract Benzofused 1H-1,3-azaphospholes are lithiated at the N-atom by tBuLi but phosphinylation takes place at either the N- or the P-atom. Smaller chlorophosphines react at nitrogen, bulkier react at phosphorus. Substituents at C2 promote the latter mode. N-Substituted 2H-1,3-benzazaphospholes undergo CH-metalation or addition at the P˭C bond, depending on the conditions, and allow access to 2-functionally substituted benzazaphospholes or their 2,3-dihydro derivatives, new σ2P,X or σ3P,X hybrid ligands (X=O,P).
The transfer of tin and germanium atoms from N-heterocyclic stannylenes and germylenes to diazadienes.
2005
New N-heterocyclic stannylenes and germylenes were synthesized by transamination of E[N(SiMe3)2] (E = Ge, Sn) with alpha-amino-aldimines or ethylidene-1,2-diamines and were characterized by spectroscopic methods and in the case of the germylene 10 g by X-ray diffraction. The reactions of several germylenes and stannylenes with diazadienes were studied by using dynamic NMR and computational methods. Experimental and theoretical studies confirmed that metathesis with exchange of the Group 14 atom is feasible for both stannylenes and germylenes, with exchange rates being generally higher for stannylenes. The metathesis of the diazadiene 3 b and the stannylene 1 b follows second-order kinetics …
[Bis(phosphonio)isophosphindolide]silver complexes
1996
The outcome of reactions of bis(phosphonio)isophosphindolide salts 1[X] and 6[X] (X- Cl-, Br-, CF3SO3-) with silver salts AgY (Y- = CF3SO3-, CF3CO2-, CH3CO2-, 1/2 SO4-) depends strongly on the available anions X, Y. If X-, Y- CF3SO3-, both mononuclear and dinuclear silver complexes are formed which exhibit either μ1,μ1(P) or μ2,η1(P) coordination of the cations 1, 6 to one or to both metals. In solution, dynamic equilibria between both types of products and free 1, 6 were detected by 31P-NMR spectroscopy. Mononuclear (4a, 7) and dinuclear (5a, 8) complexes were isolated as solvates with CHCl3 or THF. If X-, Y- = CF3CO2, only equilibrium mixtures between the free ligands and silver complexes…
Strukturanalytische Untersuchungen P-substituierter 1,3,2-Diazaphospholidine
2011
2-Diphenylphosphanyl-1,3,2-diazaphospholidines were prepared via metathesis from 2-chloro-1,3,2-diazaphospholidines and LiPPh2. For some of the products, symmetrisation to tetraphenyldiphosphane and 2,2′-bis-1,3,2-diazaphospholidinyls was observed. Most of the derivatives were characterised by single-crystal X-ray diffraction, which showed that all compounds studied feature elongated exocyclic P–Cl or P–P-bonds, respectively. The extent of this bond lengthening is in the P-phosphanyl-substituted species similar and in the P-chloro-derivatives less pronounced than in corresponding CC-unsaturated 1,3,2-diazaphospholenes. Structure correlation involving comparison of exocyclic P–X and endocycl…