RESUMEN
Different cyclic (alkyl)(amino)carbenes (CAACs) were reacted with yellow arsenic. Several products [(CAAC-n)2 (µ,η1:1 -As2 )] (n=1 (1), 4 (2)), [(CAAC-2)3 (µ3 ,η1:1:1 -As4 )] (3) and [(CAAC-3)4 (µ4 ,η1:1:1:1 - As8 )] (6) were isolated due to the differing steric properties of CAAC-1-4. The products contain As2 , As4 or As8 units and represent the first examples of CAACs-substituted products of yellow arsenic. The reactivity of As4 was compared with the reactivities of P4 and the interpnictogen compound AsP3 , which led to a series of phosphorus-containing derivatives such as ([(CAAC-3)3 (µ3 ,η1:1:1 -P4 )] (4) and [(CAAC-3)4 (µ4 ,η1:1:1:1 -P8 )] (7)) and [(CAAC-3)3 (µ3 ,η1:1:1 -AsP3 )] (5). The products were characterized by spectroscopic and crystallographic methods and DFT computations were performed to clarify their formation pathway.
RESUMEN
Whereas the self-assembly of pentaphosphaferrocenes [CpRFe(η5-P5)] (CpR = Cp*, Cp×, and CpBn) with Cu and Ag salts has been well-studied in the past, the coordination chemistry toward Au complexes has been left untouched so far. Herein, the results of the self-assembly processes of [CpRFe(η5-P5)] with Au salts of different anions (GaCl4-, SbF6-, and Al(OC(CF3)3)4 (TEF-)) are reported. Next to a variety of molecular coordination products, the first coordination polymers based on polyphosphorus ligand complexes and Au salts are also obtained. Thereby, a 2D coordination polymer comprising metal vacancies is isolated. In all products, the Au centers are coordinated in a linear or a trigonal planar environment. In solution, highly dynamic processes are observed. Variable-temperature NMR spectroscopy, solid-state NMR spectroscopy, and X-ray powder diffraction were applied to gain further insight into selected coordination compounds.
RESUMEN
The versatile coordination behavior of the P4 butterfly complex [{Cp'''Fe(CO)2 }2 (µ,η1:1 -P4 )] (1, Cp'''=η5 -C5 H2t Bu3 ) towards different iron(II) compounds is presented. The reaction of 1 with [FeBr2 â dme] (dme=dimethoxyethane) leads to the chelate complex [{Cp'''Fe(CO)2 }2 (µ3 ,η1:1:2 -P4 ){FeBr2 }] (2), whereas, in the reaction with [Fe(CH3 CN)6 ][PF6 ]2 , an unprecedented rearrangement of the P4 butterfly structural motif leads to the cyclo-P4 moiety in {(Cp'''Fe(CO)2 )2 (µ3 ,η1:1:4 -P4 )}2 Fe][PF6 ]2 (3). Complex 3 represents the first fully characterized "carbon-free" sandwich complex containing cyclo-P4 R2 ligands in a homoleptic-like iron-phosphorus-containing molecule. Alternatively, 2 can be transformed into 3 by halogen abstraction and subsequent coordination of 1. The additional isolated side products, [{Cp'''Fe(CO)2 }2 (µ3 ,η1:1:2 -P4 ){Cp'''Fe(CO)}][PF6 ] (4) and [{Cp'''Fe(CO)2 }2 (µ3 ,η1:1:4 -P4 ){Cp'''Fe}][PF6 ] (5), give insight into the stepwise activation of the P4 butterfly moiety in 1.
RESUMEN
Phosphaferrocenes in combination with coinage metal salts proved to be excellent building blocks in supramolecular chemistry for the buildup of oligomeric and polymeric assemblies. The synthesis of a series of novel phosphaferrocenes containing the 1,3-P2C3iPr3 and/or the 1,2,4-P3C2iPr2 ligand is described herein. The self-assembly processes of the 1,3-diphospha-, 1,2,4-triphospha-, and 1,1',2,3',4-pentaphosphaferrocenes with CuI halides led to the formation of 1D or 2D polymers. With [Cp*Fe(η5-P2C3iPr3)] (Cp* = η5-C5Me5), infinite chains are formed, whereas with [(η5-P3C2iPr2)Fe(η5-P2C3iPr3)] 1D ladderlike structures are obtained. These are the first polymers containing such a di- and pentaphosphaferrocene, respectively. On the other hand, the use of [Cp*Fe(η5-P3C2iPr2)] leads to the construction of 2D networks with intact sandwich complexes, which is uncommon for this class of complexes.
RESUMEN
The coordination properties of new types of bidentate phosphane and arsane ligands with a narrow bite angle are reported. The reactions of [{Cp'''Fe(CO)2 }2 (µ,η(1:1) -P4 )] (1 a) with the copper salt [Cu(CH3 CN)4 ][BF4 ] leads, depending on the stoichiometry, to the formation of the spiro compound [{{Cp'''Fe(CO)2 }2 (µ3 ,η(1:1:1:1) -P4 )}2 Cu](+) [BF4 ](-) (2) or the monoadduct [{Cp'''Fe(CO)2 }2 (µ3 ,η(1:1:2) -P4 ){Cu(MeCN)}](+) [BF4 ](-) (3). Similarly, the arsane ligand [{Cp'''Fe(CO)2 }2 (µ,η(1:1) -As4 )] (1 b) reacts with [Cu(CH3 CN)4 ][BF4 ] to give [{{Cp'''Fe(CO)2 }2 (µ3 ,η(1:1:1:1) -As4 )}2 Cu](+) [BF4 ](-) (5). Protonation of 1 a occurs at the "wing tip" phosphorus atoms, which is in line with the results of DFT calculations. The compounds are characterized by spectroscopic methods (heteronuclear NMR spectroscopy and IR spectrometry) and by single-crystal X-ray diffraction studies.
RESUMEN
The selective formation of the dinuclear butterfly complexes [{Cp'''Fe(CO)2}2(µ,η(1:1)-E4)] (E = P (1 a), As (1 b)) and [{Cp*Cr(CO)3}2(µ,η(1:1)-E4)] (E = P (2 a), As (2 b)) as new representatives of this rare class of compounds was found by reaction of E4 with the corresponding dimeric carbonyl complexes. Complexes 1 b and 2 b are the first As4 butterfly compounds with a bridging coordination mode. Moreover, first studies regarding the reactivity of 1 b and 2 b are presented, revealing the formation of the unprecedented As8 cuneane complexes [{Cp'''Fe(CO)2}2{Cp'''Fe(CO)}2(µ4,η(1:1:2:2)-As8)] (3 b) and [{Cp*Cr(CO)3}4(µ4,η(1:1:1:1)-As8)] (4). The compounds are fully characterized by NMR and IR spectroscopy as well as by X-ray structure analysis. In addition, DFT calculations give insight into the transformation pathway from the E4 butterfly to the corresponding cuneane structural motif.
RESUMEN
A new and selective one-step synthesis was developed for the first activation stage of white phosphorus by organic radicals. The reactions of NaCp(R) with P4 in the presence of CuX or FeBr3 leads to the clean formation of organic substituted P4 butterfly compounds Cp(R)2P4 (Cp(R): Cp(BIG)=C5(4-nBuC6H4)5 (1 a), Cp'''=C5H2tBu3 (1 b), Cp*=C5Me5 (1 c) und Cp(4iPr)=C5HiPr4 (1 d)). The reaction proceeds via the activation of P4 by Cp(R) radicals mediated by transition metals. The newly formed organic derivatives of P4 have been comprehensively characterized by NMR spectroscopy and X-ray crystallography.
RESUMEN
The reaction of a P4 butterfly complex with yellow arsenic yields the largest mixed Pn Asm ligand complexes synthesized to date. [{Cp'''Fe(CO)2 }2 (µ,η(1:1) -P4 )] reacts with As4 to yield [{Cp'''Fe}2 (µ,η(4:4) -Pn As4-n )] and [Cp'''Fe(η(5) -Pn As5-n )]. Mass spectrometry together with NMR spectroscopy and X-ray crystallography give clear evidence about the arrangement of the E positions within the cyclo-E5 and E4 moieties of the products. Moreover, the results of DFT calculations agree well with the experimental determined outcomes. By coordinating the E4 complex [{Cp'''Fe}2 (µ,η(4:4) -Pn As4-n )] with CuCl, a rearrangement of the E positions occurs in favor with a preferred phosphorus coordination towards copper atoms in the resulting 1D polymeric chain.
RESUMEN
One time only: The reaction of [Cp*Ru(dppe)Cl] with the potent As4 transfer reagent [Ag(η(2)-As4)2](+)[pftb](-) leads to [Cp*Ru(dppe)(η(1)-As4)](+)[pftb](-) with an unprecedented end-on-coordinated As4 tetrahedron. Reaction with a second cationic ruthenium complex fragment does not lead to a second end-on coordination but to the cleavage of one basal As-As bond. This behavior, which differs from its phosphorus analogues, is rationalized by DFT calculations.
RESUMEN
The molecular structures, chemical bonding and magnetochemistry of the three-coordinate iron(II) NHC complexes [(NHC)Fe{N(SiMe(3))(2)}(2)] (NHC = IPr, 2; NHC = IMes, 3) are reported.
RESUMEN
A novel 1,2,3-triphosphaferrocene has been synthesised, which reacts with CuBr to give a 2D polymer, revealing an unprecedented pi-stacking of the triphospholyl moieties.
