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Compared to phosphines with guanidinium tags, studied as polar ligands for aqueous catalysis, their counterparts bearing guanidine substituents received only limited attention. This contribution focuses on the coordination of phosphinoferrocene guanidine Ph2PfcN＝C(NHiPr)2 (1iPr, fc = ferrocene-1,1′-diyl) as a hybrid, P,N-donor ligand to Group 10 metals. In its native state, 1iPr coordinated as a P,N-chelating ligand, affording [M(X)(Y)(1iPr-κ2P,N)] (M/X/Y = Pd/Cl/Cl, Pd/Br/4-C6H4CN, Pt/Cl/Cl; the corresponding Ni(II) complex was not isolated). While [PdCl2(1iPr-κ2P,N)] converted into [PdCl(1iPr-κ3Fe,P,N)]+ species with Fe–Pd interaction, upon chloride removal, the analogous Pt(II) complex dimerised into [Pt2(μ-Cl)2(1iPr-κ2P,N)2]2+. Deprotonation of [PdCl2(1iPr-κ2P,N)] produced a unique, doubly chelating phosphinoguanidinate complex [PdCl{(1iPr–H)-κ3P,N,N′}], which was smoothly converted into [Pd(MeCN){(1iPr–H)-κ3P,N,N′}][SbF6]. The latter, a convenient starting material for substitution reactions, was used to prepare either [Pd(L){(1iPr–H)-κ3P,N,N′}][SbF6] (L = 4-(dimethylamino)pyridine and 2-phenylpyridine), by simple substitution, or the hydroxide and acetylacetonate (acac) complexes, [Pd2(μ-OH)2(1iPr-κ2P,N)2][SbF6]2 and [Pd(acac)(1iPr-κ2P,N)][SbF6], by substitution with concomitant proton transfer. In contrast, protonation of the guanidine moiety prevented its coordination, as shown in reactions of the salts (1iPrH)Cl and (1iPrH)[SbF6]. Depending on the metal-to-ligand ratio, adding (1iPrH)[SbF6] to [PdCl2(MeCN)2] produced [Pd2Cl2(μ-Cl)2(1iPrH-κP)2][SbF6]2 or [PdCl2(1iPrH-κP)2][SbF6]2. Analogous reactions involving (1iPrH)Cl were more complicated due to competing coordination of the chloride anion, leading to (in addition to other compounds) the zwitterionic complex [PdCl3(1iPrH-κP)], which was alternatively obtained by selective protonation of [PdCl2(1iPr-κ2P,N)] with HCl. Apparently, the protonation state of the guanidine moiety controls the coordination behaviour of phosphinoferrocene guanidines. [ABSTRACT FROM AUTHOR]

Readily available phosphinoferrocene guanidines coordinate Pd(II) as P,N-chelating or κ3P,N,Fe-bound ligands. As the latter, they give rise to the first donor-asymmetric complexes featuring Fe–Pd dative bonds, which were studied using direct (spectroscopic and electrochemical) methods and theoretical (DFT) approaches. [ABSTRACT FROM AUTHOR]

A series of cationic Pt(II) complexes with chelating bis‐carbene and P,P‐ or P,S‐ligands, viz. [(C^C)Pt(X^Y)][BF4]2 (2a–e), where C^C = methylenebis(3‐methyl‐1H‐imidazol‐1‐yl‐2‐ylidene, and X^Y = Ph2PCH2CH2PPh2 (dppe) (a), Ph2P(CH2)3PPh2 (dppp) (b), 1,2‐(Ph2P)2C6H4 (dppbz) (c), [Fe(η5‐C5H4PPh2)2] (dppf) (d), and Ph2PCH2CH2SPh (e), were synthesized and structurally characterized by NMR and MS spectroscopy and by single‐crystal X‐ray diffraction analysis. Furthermore, photophysical measurements showed that these compounds were non‐emissive at room temperature. However, when cooled to 77 K, compounds 2a, 2b and 2c showed weak luminescence in the near UV region with emission maxima in the 380–395 nm range. [ABSTRACT FROM AUTHOR]

This contribution expands the still narrow class of functional ferrocene phosphanes with polar cationic groups, focusing on the synthesis and catalytic use of a series of phosphanylferrocene ligands bearing positively charged guanidinium tags, [R2PfcCH2NHC(NH2)2]Cl (3a–d), where fc = ferrocene‐1,1′‐diyl, R = isopropyl (a), cyclohexyl (b), phenyl (c), and 2‐furyl (d). To probe the influence of phosphane substituents, these compounds were studied as supporting ligands in Pd‐catalyzed Suzuki–Miyaura cross‐coupling of acyl chlorides with arylboronic acids, in analogous coupling of aryl bromides with arylboronic acids, and in Rh‐catalyzed hydroformylation of 1‐hexene using trans‐[RhCl(CO){R2PfcCH2NHC(NH2)2‐κP}2]Cl2 complexes (4a–d) as pre‐catalysts. The outcome of the cross‐coupling reactions strongly depended on the starting materials, and no ligand generated a universally applicable catalyst when combined with Pd(OAc)2. In the hydroformylation reactions, the catalyst based on 4d led to lower conversions than all others, which performed rather similarly. Overall, the phenyl‐substituted phosphane 3c emerged as a good compromise, giving rise to reasonably efficient and stable catalysts in most cases (except for Suzuki–Miyaura biaryl cross‐couplings, wherein electron‐rich alkylphosphanes performed better than 3c). [ABSTRACT FROM AUTHOR]

Gold(i) phosphine complexes are often used in catalysis, but the role of their auxiliary ligands still remains poorly understood. Thus, building on our previous research, we prepared a series of Au(i) complexes [Au2(μ-R2PfcCN)2][SbF6]2 (fc = ferrocene-1,1′-diyl) to assess the effect of phosphine groups PR2 on the catalytic properties of these highly catalytically active, dimeric compounds. Catalytic testing in Au-mediated cyclisation of N-propargyl amides to 2-substituted 5-methyleneoxazolines showed that weaker donating phosphines gave rise to more active, albeit partly destabilised, catalysts. Nevertheless, thanks to their self-stabilisation by reversible nitrile coordination, [Au2(μ-R2PfcCN)2]+ cations readily converted into catalytically active species (by dissociation) and, in addition, remained catalytically active even at very low metal loadings. The experimental results were supported by the trends in 1JPSe coupling constants for R2P(Se)fcCN as a measure of ligand basicity, and by DFT calculations. [ABSTRACT FROM AUTHOR]

The coordination properties of phosphinoferrocene oxazolines with Group 11 metal ions were probed through a series of reactions between various metal precursors and the model ligand, rac-1-[4,5-dihydro-4,4-dimethyl-2-oxazolyl]-2-(diphenylphosphino)ferrocene (1). The reactions of 1 with CuX and AgCl produced the halide-bridged dimers [M(μ-X)(1-κ2N,P)], where M/X = Cu/Cl (2a), Cu/Br (2b), Cu/I (2c), and Ag/Cl (3), whereas the reaction with [AuCl(tht)] (tht = tetrahydrothiophene) yielded the chlorogold(i) complex [AuCl(1-κP)] (4). When metal precursors without strongly coordinating halide ligands were used (viz., [Cu(MeCN)4][PF6] and AgClO4), the complexation reactions generated bis-chelate complexes [M(1-κ2N,P)2]X (5: M/X = Cu/PF6, 6: M/X = Ag/ClO4). A similar reaction with [Au(tht)2]ClO4 produced [Au(1-κP)2]ClO4 (7), wherein the gold centre is linearly coordinated by two phosphine moieties. All complexes except for 4 were structurally authenticated by X-ray crystallography. The observed coordination behaviour and structures of the isolated complexes are discussed in the context of the catalytic properties of chiral ligands structurally related to the model compound 1. [ABSTRACT FROM AUTHOR]

[1′-(Diphenylphosphino)ferrocenyl]methylamine ( 1 ) reacts with Ph 2 PH/(CH 2 O) x or [Ph 2 P(CH 2 OH) 2 ]Cl to give mixtures of Ph 2 PfcCH 2 NHCH 2 PPh 2 and Ph 2 PfcCH 2 N(CH 2 PPh 2 ) 2 in which the triphosphine dominates (fc = ferrocene-1,1′-diyl). To avoid unwanted two-fold phosphinomethylation, the amine group in 1 was alkylated. As expected, the reaction of the N -methyl analogue Ph 2 PfcCH 2 NHMe ( 5 ), obtained by reductive methylation of the aldehyde Ph 2 PfcCHO, with [Ph 2 P(CH 2 OH) 2 ]Cl, only led to the diphosphine Ph 2 PfcCH 2 N(Me)CH 2 PPh 2 ( 6 ). The diphosphine was structurally characterized and further reacted with [PdCl 2 (MeCN) 2 ] and [PdCl(Me)(cod)] (cod = η 2 :η 2 -cycloocta-1,5-diene), affording the respective trans -chelate complexes [PdCl(X){Ph 2 PfcCH 2 N(Me)CH 2 PPh 2 -κ 2 P , P ′}] ( 7a : X = Cl; 7b : X = Me), which were also structurally authenticated by X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

A polar phosphanylferrocene donor equipped with a hydrophilic guanidinium pendant, Ph2PfcCH2NHC(NH)NH2 ·HCl ( 1·HCl; fc = ferrocene-1,1′-diyl), has been prepared from the corresponding amine hydrochloride, Ph2PfcCH2NH2 ·HCl ( 2·HCl), and studied as a ligand for PdII. The reactions of 1·HCl with [PdCl2(MeCN)2] in 1:1 and 1:2 Pd/ligand ratios led to an unexpected zwitterionic complex, [PdCl3( 1H-κ P)] ( 3), and the expected bis(phosphane) complex, trans-[PdCl2( 1H-κ P)2]Cl2 ( 4), which were structurally characterized. The defined and air-stable solvated complex 3·Me2CO and the in situ generated Pd(OAc)2/ 1·HCl system were found to be active catalysts for the Suzuki-Miyaura cross-coupling of anionic triolborates with aryl bromides, giving the corresponding biphenyls. These reactions, which do not require the presence of an additional base, were advantageously performed in aqueous ethanol, and the coupling products were isolated in good to excellent yields. [ABSTRACT FROM AUTHOR]

{[Tris(hydroxymethyl)methylamino]carbonyl}ferrocene ( 1 ) reacts with phosphorus(III) chloride in the presence of pyridine or triethylamine to afford a ferrocenyl-substituted bicyclic phosphite, {[(2,6,7-trioxa-1-phosphabicyclo[2.2.2]oct-4-yl)amino]carbonyl}ferrocene ( 2 ), in a moderate yield. (4,5-Dihydro-4,4-bis(chloromethyl)-2-oxazolyl)ferrocene ( 3 ) is found to be formed in some experiments as a minor side-product, resulting presumably via halogenation of 1 and base-induced cyclization of an intermediate chloromethyl derivative. The reaction of 2 with [W(CO) 4 (cod)] (cod = cycloocta-1,5-diene) at elevated temperature produces bis-phosphite complex cis -[W(CO) 4 ( 2 -κ P ) 2 ] ( 4 ) as the major product. All newly prepared compounds have been characterized by spectroscopic methods (IR, NMR and mass spectrometry) and elemental analysis. The crystal structures of 2 , 3 ·1/2H 2 O and 4 ·Me 2 CO·H 2 O were determined by single-crystal X-ray diffraction and the redox behaviour of phosphite 2 and the W(0) complex 4 was studied by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Knowledge and skills with information and communications technology (ICT) usage are an essential part of modern life. In recent years, the age at which children have their first contact with ICT and first use of ICT has been decreasing. This can significantly affect the development of their digital literacy. This study investigates the relationship between the age at which children start using a computer and the degree of their perceived ICT competence and autonomy at the age of fifteen. It proposes a multiple mediator model within which the investigated relationship is mediated by ICT usage, ICT interest, and the degree to which ICT is a part of students' everyday social interactions. The model is then tested using data from 21 European OECD countries. The test results show that children who start using a computer at a later age (after the age of seven) demonstrate significantly lower ICT competence and ICT autonomy at the age of fifteen. The results of the mediation analysis suggest that the degree of ICT usage in the home environment for school purposes or activities seems less significant to the development of ICT competence and ICT autonomy than other studied ICT-related variables. • Differences in ICT competence and autonomy are mostly due to out-of-school factors. • Age at first PC use is related to students' ICT competence at 15 years of age. • Other ICT-related variables mediate the development of ICT competence and autonomy. • Pre-school period is critical for the development of students' ICT competence. [ABSTRACT FROM AUTHOR]