Arranging up to six ferrocene carboxamides around metal centres

Metastable Charged Dimers in Organometallic Species: A Look into Hydrogen Bonding between Metallocene Derivatives

Multiply charged complexes bound by noncovalent interactions have been previously described in the literature, although they were mostly focused on organic and main group inorganic systems. In this work, we show that similar complexes can also be found for organometallic systems containing transition metals and deepen in the reasons behind the existence of these species. We have studied the structures, binding energies, and dissociation profiles in the gas phase of a series of charged hydrogen-bonded dimers of metallocene (Ru, Co, Rh, and Mn) derivatives isoelectronic with the ferrocene dimer. Our results indicate that the carboxylic acid-containing dimers are more strongly bonded and present larger barriers to dissociation than the amide ones and that the cationic complexes tend to be more stable than the anionic ones. Additionally, we describe for the first time the symmetric proton transfer that can occur while in the metastable phase. Finally, we use a density-based energy decomposition analysis to shine light on the nature of the interaction between the dimers.

Synthesis and coordination of hybrid phosphinoferrocenes with extended donor pendants

Combining a phosphinoferrocene fragment with extended multidonor moieties affords novel, flexible multidonor pro-ligands. This contribution describes the synthesis of two structurally similar functional phosphines, Ph₂PfcNHC(O)CH₂PPh₂ (1) and Ph₂PfcNHCH₂CH₂PPh₂ (2, fc = ferrocene-1,1'-diyl), and their coordination behaviour towards Pd(II). The former amidophosphine reacts with [PdCl₂(MeCN)₂] to produce the chelate complex [PdCl₂(1-κ²P,P')] as a mixture of cis and trans isomers, which convert into bis-chelate [PdCl₂(Ph₂PfcNC(O)CH₂PPh₂-κ³P,P',N)] upon reacting with a strong base (KOt-Bu). In contrast, the more flexible and more basic phosphinoamine 2 directly forms the cationic bis-chelate complex [PdCl(2-κ³P,P',N)]Cl via spontaneous self-ionisation. Subsequent halogen abstraction with Ag[SbF₆] results either in counter ion exchange to give [PdCl(2-κ³P,P',N)][SbF₆] or in the formation of a structurally unique complex [PdCl(2-κ⁴Fe,P,P',N)][SbF₆]₂ with an Fe → Pd dative interaction, depending on the amount of silver(I) salt used (1 or 2 equiv.).

Synthesis of phosphinoferrocene amides and thioamides from carbamoyl chlorides and the structural chemistry of Group 11 metal complexes with these mixed-donor ligands

The reaction of in situ generated 1'-(diphenylphosphino)-1-lithioferrocene with carbamoyl chlorides, ClC(E)NMe2, affords the corresponding (thio)amides, Ph2PfcC(E)NMe2 (E = O (), S (); fc = ferrocene-1,1'-diyl). These compounds as well as their analogues, Ph2PfcC(O)NHMe () and Ph2PfcC(O)NH2 (), prepared from 1'-(diphenylphosphino)ferrocene-1-carboxylic acid (Hdpf) were studied as ligands for the Group 11 metal ions. In the reactions with [Cu(MeCN)4][BF4], the amides give rise to bis-chelate complexes of the type [Cu(L-κ(2)O,P)2][BF4]. Similar products, [Ag(L-κ(2)O,P)2]ClO4, are obtained from silver(i) perchlorate and , or . In contrast, the reaction of AgClO4 with produces a unique molecular dimer [Ag()(ClO4-κO)]2, where the metal centres are bridged by the sulfur atoms of the P,S-chelating thioamides. The reactions of with [AuCl(tht)] (tht = tetrahydrothiophene) afford the expected gold(i)-phosphine complexes, [AuCl(L-κP)], containing uncoordinated (thio)amide moieties. Hemilabile coordination of the phosphinoamide ligands in complexes with the soft Group 11 metal ions is established by the crystal structure of a solvento complex, [Cu(-κ(2)O,P)(-κP)(CHCl3-κCl)][BF4], which was isolated serendipitously during an attempted crystallisation of [Cu(-κ(2)O,P)2][BF4]. All of the compounds are characterised by spectroscopic methods, and the structures of several representatives of both the free phosphinoamides and their complexes are determined by X-ray diffraction analysis and further studied by DFT calculations and cyclic voltammetry.

Bis(ferrocene-carboxyl-ato-κO)bis-(2-pyridyl-methanol-κN,O)cobalt(II)

The title complex mol­ecule, [Fe₂Co(C₅H₅)₂(C₆H₄O₂)₂(C₆H₇NO)₂], has a crystallographic imposed centre of symmetry. The Co^II atom displays a distorted octa­hedral coordination geometry, provided by the O atoms of two monodentate ferrocene­carboxyl­ate anions and by the N and O atoms of two 2-pyridyl­methanol mol­ecule. The mol­ecular conformation is stabilized by intra­molecular C—H⋯O hydrogen bonds.

Synthesis of a new family of hexakisferrocenyl hexagons and their electrochemical behavior

The design and synthesis of two new hexakisferrocenyl hexagons has been achieved via coordination-driven self-assembly wherein the size and relative distribution of six ferrocene moieties has been precisely controlled. Insight into the structure and electronic properties of these supramolecules was obtained through electrochemical studies.