| Abstract: | The major directions of this dissertation involve (1) the syntheses and characterization of molecular polygons incorporating sp-hybridized carbon linkers and L₂Pt corners (L₂ = cis-1,3-diphosphine), (2) the development of protected carbon chain complexes featuring fluorous phosphine ligands and (3) click reactions of metal terminal polyynyl complexes and further metallations of the resulting triazole rings. A brief overview is provided in Chapter I. Chapter II details the syntheses of molecular squares containing bidendate diphosphine ligands of the formula R₂C(CH₂PPh₂)₂ where R = Me, Et, n-Bu, n-Dec, Bn, and p-tolCH₂ (general designation dppp*), in which the R₂ groups are intended to circumvent the solubility issues encountered by others. Their syntheses involve double substitutions of the dimesylate compounds R₂C(CH₂OMs)₂ using KPPh₂. Building blocks of the formulae (dppp*)PtCl₂ and (dppp*)Pt((C=̲C)₂H)2 are synthesized and characterized, including one crystal structure of the latter. The target complexes are accessed by reactions of (dppp*)PtCl₂ with (dppp*)Pt((C=̲C)₂H)₂ under Sonogashira type conditions. Six new squares of the formula [(R₂C(CH₂PPh₂)₂)Pt(C=̲C)₂]₄ are characterized including two crystal structures. Further topics include approaches to higher homologues and cyclocarbon synthesis. Chapter III focuses on carbon chain complexes bearing fluorous phosphine ligands of the formula P((CH₂)mRfn)₃ (Rfn = (CF₂)n-1CF₃; m/n = 2/8, 3/8, and 3/10). Precursors of the formula trans-(C₆F₅)((Rfn(CH₂)m)₃P)₂PtCl are synthesized and characterized, including one crystal structure, which reveals phase separation of the fluorous and non-fluorous domains. Reactions with butadiyne give trans-(C₆F₅)((Rfn(CH₂)m)₃P)₂Pt(C=̲C)₂H. Oxidative homocouplings afford the target complexes trans,trans-(C₆F₅)((Rfn(CH₂)m)₃P)₂Pt(C=̲C)₄(C₆F₅)(P((CH₂)mRfn)₃)₂Pt. Cyclic voltammetry indicates irreversible oxidations of the title compounds, in contrast to partially reversible oxidations of non-fluorous analogues. Chapter IV focuses on multimetallic complexes achieved by click reactions in metal coordination spheres. The copper catalyzed click reaction between trans-(C₆F₅)(p-tol₃P)₂Pt(C=̲C)₂H (1) and ([eta]⁵-C₅H₄N₃)Re(CO)₃ affords the bimetallic 1,2,3-triazole trans-(C₆F₅)(p-tol₃P)₂PtC=̲CC=CHN(([eta]⁵1-C₅H₄)Re(CO)₃)N=N. Further reactions with Re(CO)₅OTf and Re(CO)₅Br give trimetallated adducts, which represent the first species of this type. An alternative route to a trimetallic complex involves the twofold cycloaddition of the diazide ([eta]⁵-C₅H₄N₃)₂Fe and 1, giving ([eta]⁵-C₅H₄44NN=N-C(trans-(C=̲C)Pt(Pp-tol₃)₂(C₆F₅)=CH)₂Fe. The crystal structures of the di and trimetallic complexes are compared, but attempts to achieve a fourth metallation involving the =CH groups are unsuccessful. However, when the triazolium salt [trans-(C₆F₅)(p-tol₃P)₂PtC=̲CC=CHN(CH₂C₆H₅)N=N(Me)]⁺ I⁻ is treated with Ag₂O and [Rh(COD)Cl]₂, a =CRh adduct is obtained. The success of =CH metallation is correlated to the ¹H NMR chemical shift, indicative of an electronic effect. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148159 |
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