Sterically-directed consecutive and size-selective self-assembly of palladium diphosphane complexes with an Ar-BIAN ligand: unexpected formation of pentameric and hexameric aggregates.

摘要: The coordination properties of N,N'-bis[4-(4-pyridyl)phenyl]acenaphthenequinonediimine (L(1)) and N,N'-bis[4-(2-pyridyl)phenyl]acenaphthenequinonediimine (L(2)) were investigated in self-assembly with palladium diphosphane complexes [Pd(P;P)(H(2)O)(2)](OTf)(2) (OTf = triflate) by using various analytical techniques, including multinuclear ((1)H, (15)N, (31)P) NMR spectroscopy mass spectrometry (P;P dppp, dppf, dppe; dppp bis(diphenylphosphanyl)propane, dppf bis(diphenylphosphanyl)ferrocene, dppe bis(diphenylphosphanyl)ethane). Beside the expected trimeric tetrameric species, interaction an equimolar mixture [Pd(dppp)](2+) ions L(1) also generates pentameric aggregates. Due to E/Z isomerism L(1), a dimeric product was observed. In all these which correspond general formula [Pd(dppp)L(1)](n)(OTf)(2n) (n 2-5), ligand is coordinated Pd center only through terminal pyridyl groups. Introduction second equivalent tecton results internal, sterically more encumbered chelating site induces enhancement higher nuclearity components. presence higher-order aggregates 5, 6), unexpected for cis-protected corners linear ditopic bridging ligands, has been demonstrated both mass-spectrometric DOSY spectroscopic analysis. sequential ion attributed dissimilar steric two sites. self-assembled species formed 1:1:1 [Pd(dppp)](2+)/[Pd(dppe)](2+)/L(1), demanding tectons are attached selectively groups, whereas hindered imino nitrogen atoms coordinate less bulky complexes, thus resulting directed, size-selective sorting metal tectons. propensity new ligands incorporate hydrogen-bonded solvent molecules at confirmed X-ray diffraction studies.