Neutral and Cationic Complexes with P-Bonded 2-Pyridylphosphines as N-Donor Ligands toward Rhodium. Electrical Charge vs Steric Hindrance on the Conformational Control

Base-assisted synthesis of 4-pyridinate gold(I) metallaligands: a study of their use in self-assembly reactions

The synthesis of di- and tritopic gold(i) metallaligands of the type [(Au4-py)2(μ2-diphosphane)] (diphosphane = bis(diphenylphosphanyl)isopropane or dppip (1), 1,2-bis(diphenylphosphanyl)ethane or dppe (2), 1,3-bis(diphenylphosphanyl)propane or dppp (3) and 1,4-bis(diphenylphosphanyl)butane or dppb (4)) and [(Au4-py)3(μ3-triphosphane)] (triphosphane = 1,1,1-tris(diphenylphosphanylmethyl)ethane or triphos (5) and 1,3,5-tris(diphenylphosphanyl)benzene or triphosph (6)) from [(AuCl)2(μ2-diphosphane)] or [(AuCl)3(μ3-triphosphane)] and 4-pyridylboronic acid in the presence of Cs2CO3 has been conducted. Interestingly, when [(AuCl)2(μ2-dppm)] (dppm = bis(diphenylphosphanyl)methane) was used as a starting material, the cyclic tetranuclear gold(i) compound [(Au4-py)2(CH)2{μ2-Au(PPh2)2}2] (I) was obtained instead. All the products have been characterized by IR and multinuclear NMR spectroscopy, mass spectrometry and elemental analysis and in the case of 1, 3, 5 and I by X-ray crystallography, which showed the presence of aurophilic interactions in all of them. The obtained metallaligands have been used as building blocks in self-assembly reactions with cis-blocked palladium or platinum acceptor moieties producing [2 + 2] metallamacrocycles or trigonal bipyramidal (TBP) [2 + 3] metallacages in good yields. The photophysical properties of both the metallaligands and the corresponding assemblies have been investigated.

Luminescence behaviour of Au(I)-Cu(I) heterobimetallic coordination polymers based on alkynyl-tris(2-pyridyl)phosphine Au(I) complexes

A set of alkynyl-tris(2-pyridyl)phosphine Au(i) complexes was synthesized and characterized. Free coordination functions on the ligand environment periphery, namely 'scorpionate' PPy3 and the C[triple bond, length as m-dash]C bond, allowed these ditopic metalloligands to be selectively linked to 1D coordination polymers by reaction with Cu(i), which used both Cu-(N-PPy3) and Cu-(η2-C[triple bond, length as m-dash]C) coordination modes. Single-crystal and powder XRD, NMR, and XPS techniques were used to characterize the coordination polymers obtained. Heterobimetallic Au(i)-Cu(i) coordination polymers demonstrate triplet photoluminescence which was studied by spectroscopic and computational methods to understand the pathway of energy transfer inside the chain of linked chromophore centres. The intriguing feature of the electronic structure of heterobimetallic supramolecular assemblies is the 'long-distance' electronic transition involving PhC2 and PPy3 ligands located at a distance of more than 1 nm from each other. Thus, the assembly of a heterobimetallic coordination polymer from relatively simple 'building blocks' retains the block-wise nature of the electronic structure, but the photophysical properties of the polymer are fundamentally different from the properties of discrete organometallic components.

Coordination of bis(azol-1-yl)methane-based bisphosphines towards RuII, RhI, PdII and PtII: synthesis, structural and catalytic studies

This paper describes the transition metal chemistry of three bis(X-diphenylphosphino-azol-1-yl)-based bisphosphines: bis(2-Ph₂P-imidazol-1-yl)methane (1), bis(5-Ph₂P-pyrazol-1-yl)methane (2) and bis(5-Ph₂P-1,2,4-triazol-1-yl)methane (3). These show versatility in their coordination behaviour.

Multidentate 2-pyridyl-phosphine ligands – towards ligand tuning and chirality

The incorporation of a variety of alcohols into (amino)pyridyl-phosphine frameworks provides access to a library of multidentate (alkoxy)pyridyl-phosphines. Their coordination chemistry with Cu^I is explored.

Synthesis and coordination chemistry of 1,1,1-tris-(pyrid-2-yl)ethane

The complexes [ML₂]ⁿ⁺(Mⁿ⁺= Fe²⁺, Co²⁺, Co³⁺, Cu²⁺and Ag⁺), [PdCl₂L] and [CuI(L)] are described. [AgL₂]⁺is an unusual square planar silver(i) centre (left). Exposure of [CuI(L)] to air affords mono- or dinuclear copper(ii)/carbonato products. Two of the copper complexes form crystalline hydrates with complicated hydrogen bond networks (right).