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The combination of different donor moieties often results in unconventional coordination behavior. This contribution describes the synthesis of a new hybrid ligand, phosphanylferrocene amidine Ph2PfcN=CHNMe2 (1; fc=ferrocene‐1,1′‐diyl), and its coordination behavior toward the light platinum metals. Reacting compound 1 with [PdCl2(MeCN)2] produced the chelate complex [PdCl2(1‐κ2P,N)] and the bis (phosphane) complex trans‐[PdCl2(1‐κP)2], depending on the ligand‐to‐metal stoichiometry. Halide removal from [PdCl2(1‐κ2P,N)] with Na[BARF] afforded the chloride‐bridged dimer [Pd2(μ‐Cl)2(1‐κ2P,N)2][BARF]2, which was presumably in equilibrium with the mononuclear κ3‐complex [PdCl(1‐κ3Fe,P,N)][BARF] in solution (BARF=tetrakis [3,5‐bis(trifluoromethyl)phenyl]borate). The reactions of 1 with the isoelectronic precursors [(arene)MCl(μ‐Cl)]2 (M/arene=Ru(II)/p‐cymene, and Rh(III)/C5Me5) generated the respective bridge‐cleavage products [(arene)MCl2(1‐κP)], which transformed into the P,N‐chelate complexes [(arene)MCl(1‐κ2P,N)][BARF] when treated with Na[BARF] as a chloride scavenger. All this suggests preferential coordination the phosphane moiety to soft metal ions, while the coordination of the amidine moiety can be induced through changing the reaction stoichiometry or by generating a vacant coordination site at the metal ion. The compounds were characterized using a combination of standard spectroscopic methods (multinuclear NMR, IR, and ESI MS) and single‐crystal X‐ray crystallography, and compounds 1 and 3 were further studied by cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Two homologous ferrocene phosphanylcarboxylic acids, viz., 1'-[(diphenylphosphanyl)methyl]ferrocene-1-carboxylic acid (HL1) and [1'-(diphenylphosphanyl)ferrocenyl]acetic acid (HL2), were synthesized and studied as ligands in PdII complexes. The addition of these hybrid donors to [PdCL2(MeCN)2] led to the bis-phosphane complexes trans-[PdCL2(HL1-κP)2] and trans-[PdCL2(HL2-κP)2]. In contrast, the reactions of HL1 and HL2 with the PdII acetylacetonate (acac) complexes [(LYC)Pd(acac)], where LYC = 2-[(dimethylamino-κN)methyl]phenyl-κC1 (LNC) and 2-[(methylthio-κS)methyl]phenyl-κC1 (LSC), proceeded under proton transfer and replacement of the acac ligand, giving rise to O,P-bridged phosphanylcarboxylate dimers [LYCPd(μ(P,O)- L1)]2 and molecular chelates [LYCPd(L2-κ2O,P)]2, respectively. The analogous reactions involving 1'-(diphenylphosphanyl)-1-ferrocenecarboxylic acid (Hdpf) provided the macrocyclic tetramer [LNCPd(μ(P,O)-dpf)]4 and the dimer [LSCPd(μ(P,O)-dpf)]2. The reactions of HL1 with [Pd(acac)2] only led to an ill-defined, insoluble material, whereas those with HL2 produced a separable mixture of the bis-chelate complexes trans-[Pd(L2-κ2O,P)2], cis- [Pd(L2-κ2O,P)2], and [Pd(acac)(L2-κ2O,P)]. [ABSTRACT FROM AUTHOR]

Phosphanylferrocene donors bearing polar guanidinium substituents, namely acylguanidinium chloride, [Ph2PfcCONHC(NH2)NH2]Cl ( 1), and amidoguanidinium chloride, [Ph2PfcCONHCH2CH2NHC(NH2)NH2]Cl ( 2; fc = ferrocene-1,1′-diyl), have been prepared and characterized. As functional phosphane donors, they were employed in the synthesis of PdII complexes bearing 2-[(dimethylamino)methyl-κ N]phenyl-κ C1 (LNC) and η3-allyl supporting ligands, [(LNC)PdCl(L-κ P)] and [(η3-C3H5)PdCl(L-κ P)] (L = 1 and 2), respectively. These defined complexes as well as their surrogates generated in situ from the respective palladium(II) precursor and the phosphanylferrocene ligand were evaluated as catalysts for the coupling of boronic acids with acyl chlorides to give ketones in an aqueous biphasic system. The coupling reaction proceeded best with a simple catalyst formed from Pd(OAc)2 and ligand 2, which (at 0.2 mol-% Pd loading) produced substituted benzophenones from benzoyl chlorides and benzeneboronic acids in very good yields. These yields could then be further improved by a proper choice of the reaction partners. Analogous reactions involving aliphatic substrates generally afforded lower yields. [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]

Sunlight photolysis of decamethyltitanocene dihydrosulfide [Cp*2Ti(SH)2] ( 1, Cp* = η5-C5Me5) in toluene affords the titanium sulfide clusters [(Cp*Ti)6(μ3-S)8] ( 4) and [(Cp*Ti)4(μ3-S)3(μ2-S)3] ( 5), the former in very low yield and the latter in good yield. The crystal structures of both compounds are toluene solvates and are based on a nearly regular titanium octahedron for 4 and a trigonal pyramid for 5. The [(Cp*Ti)3(μ3-S)(μ2-S)3] ( 6) complex isolated in a trace amount from the photolysis of 1 in hexane could be a precursor of 4. A plausible mechanism for the formation of 5 and 6 follows a mechanism recently proposed for photolysis of [Cp*2Ti(OH)2] by U. Rosenthal et al. [ABSTRACT FROM AUTHOR]

Sunlight photolysis of decamethyltitanocene dihydrosulfide [Cp*2Ti(SH)2] ( 1, Cp* = η5-C5Me5) in toluene affords the titanium sulfide clusters [(Cp*Ti)6(μ3-S)8] ( 4) and [(Cp*Ti)4(μ3-S)3(μ2-S)3] ( 5), the former in very low yield and the latter in good yield. The crystal structures of both compounds are toluene solvates and are based on a nearly regular titanium octahedron for 4 and a trigonal pyramid for 5. The [(Cp*Ti)3(μ3-S)(μ2-S)3] ( 6) complex isolated in a trace amount from the photolysis of 1 in hexane could be a precursor of 4. A plausible mechanism for the formation of 5 and 6 follows a mechanism recently proposed for photolysis of [Cp*2Ti(OH)2] by U. Rosenthal et al. [ABSTRACT FROM AUTHOR]