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  • Macrocyclic Complexes Derived from Four cis-L2Pt Corners and Four Butadiynediyl Linkers; Syntheses, Electronic Structures, and Square versus Skew Rhombus Geometries
Title: Macrocyclic Complexes Derived from Four cis-L2Pt Corners and Four Butadiynediyl Linkers; Syntheses, Electronic Structures, and Square versus Skew Rhombus Geometries
The dialkyl malonate derived 1,3-diphosphines R2C(CH2PPh2)2 (R=a, Me; b, Et; c, n-Bu; d, n-Dec; e, Bn; f, p-tolCH2) are combined with (p-tol3P)2PtCl2 or trans-(p-tol3P)2Pt((C≡C)2H)2 to give the chelates cis-(R2C(CH2PPh2)2)PtCl2 (2 a–f, 94–69 %) or cis-(R2C(CH2PPh2)2)Pt((C≡C)2H)2 (3 a–f, 97–54 %). Complexes 3 a–d are also available from 2 a–d and excess 1,3-butadiyne in the presence of CuI (cat.) and excess HNEt2 (87–65 %). Under similar conditions, 2 and 3 react to give the title compounds [(R2C(CH2PPh2)2)[Pt(C≡C)2]4 (4 a–f; 89–14 % (64 % avg)), from which ammonium salts such as the co-product [H2NEt2]+ Cl− are challenging to remove. Crystal structures of 4 a,b show skew rhombus as opposed to square Pt4 geometries. The NMR and IR properties of 4 a–f are similar to those of mono- or diplatinum model compounds. However, cyclic voltammetry gives only irreversible oxidations. As compared to mono-platinum or Pt(C≡C)2Pt species, the UV-visible spectra show much more intense and red-shifted bands. Time dependent DFT calculations define the transitions and principal orbitals involved. Electrostatic potential surface maps reveal strongly negative Pt4C16 cores that likely facilitate ammonium cation binding. Analogous electronic properties of Pt3C12 and Pt5C20 homologs and selected equilibria are explored computationally.  more » « less
Award ID(s):
1153085 1900549
PAR ID:
10229439
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
Chemistry
Date Published:
Journal Name:
Chemistry
Volume:
27
Issue:
39
ISSN:
0947-6539
Page Range / eLocation ID:
10021-10039
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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