Platinum complexes acetylides

Platinum blue formation, 2,265 Platinum complexes, S, 351-500 acetylacetone reactions, 2,380 acetylides reactions, 5,402 alcohols, 5,465 alkene-1,2-dithiolates optica] recording systems, 6,126 alkenes, 5,403 bonding, 5,403... 

For example, in 1963 the photochemistry of magnesium phthalocyanine with coordinated uranium cations was studied in pyridine and ethanol and indicated the occurrence of PET to the uranium complex . A rapid photoinduced electron transfer (2-20 ps) followed by an ultrafast charge recombination was shown for various zinc and magnesium porphyrins linked to a platinum terpyridine acetylide complex . The results indicated the electronic interactions between the porphyrin subunit and the platinum complex, and underscored the potential of the linking para-phenylene bisacetylene bridge to mediate a rapid electron transfer over a long donor-acceptor distance. 

Platinum(II) acetylide complexes are best prepared using Na or K acetylide in liquid ammonia solvent (equation 157).454,455 Sodium dicyanomethanide can also be used to prepare platinum(II) complexes of this anion (equation 158).456... 

The formation of carbene complexes by protonation of platinum(II) acetylides has been discussed. Both acetylide groups in frflns-Pt(C=CR)2(PMe2Ph)2 (R = H, Me) can be cleaved by HC1 (equation 222).616... 

Hexafluorobutyne-2 will add to platinum(II) complexes. The insoluble complex PtMe HB(pz)3 reacts with dissolution and the five-coordinate alkyne complexes can be isolated (equation 269).815 The coordination about platinum(II) is essentially trigonal bipyrami-dal. The C C triple bond is lengthened on coordination to 1.292(12) A and the alkyne bend-back angle is 34.4(4)°.816 These complexes have a -bonded alkyne ligand, and show different structural and reaction chemistry than platinum(II) acetylide complexes.817-821... 

Lindgren et al. studied the excited state and phosphorescence of platinum(II) acetylides (5.9) with the DFT/B3LYP method [103], The calculated UV/Vis absorption spectra revealed that the orientation of the phenyl rings relative to the P-Pt-P axis has a strong correlation with the intensity of the absorption band. The broken symmetry phenomenon was also confirmed in the lowest triplet excited state, which leads to a OC-Ph bond on one side and a C=C=C bond on the opposing side. Quadratic response calculations of spin-orbit coupling showed that the intensity of the phosphorescence of these complexes arises mainly from the a—>n type T- l) transitions localized at the OC-Pt-P fragment, but not from the delocalized 7t—type transitions. The quadratic response calculations also reproduced an increase of xR from PEj to PE2 (5.9), which was also determined experimentally. 

A variety of metal acetylide-containing stars and dendrimers have been synthesized.329-332 Dendrimer 280 was prepared via reaction of a chloro-substituted platinum complex 278 with ethynyl functionalized dendron 279 in the presence of Cul (Scheme 2.73).329 This method generated dendrimers with up to 45 platinum units. 

Platinum(0) complexes acetylides, 387 alkenes, 410 synthesis, 410 alkynes, 415 electrophilic attack, 416 NMR, 415 properties, 415 allenes, 412 cyclopropene, 411 haloalkenes reactions, 414... 

Ikeda, M., Tanabe, Y, Hasegawa, T. et al. (2006) Construction of double-stranded metaUo-supramolecular polymers with a controlled helicity by combination of salt bridges and metal coordination. Journal of the American Chemical Society, 128,6806-6807 Furusho, Y., Tanabe, Y. and Yashima, E. (2006) Double helix-to-double helix transformation, using platinum(II) acetylide complexes as surrogate linkers. Organic Letters, 8, 2583-2586 Furusho, Y. and Yashima, E. (2007) Molecular design and synthesis of artificial double helices. Chemical Record, 7, 1-11. 

Alkynyl complexes contain metal-carbon bonds in which the metal is bound to the sp-hybridized carbon at the terminus of a metal-carbon triple bond. The materials properties of these complexes have been investigated extensively. The properties of these complexes include luminescence, optical nonlinearity, electrical conductivity, and liquid crystallinity. These properties derive largely from the extensive overlap of the metal orbitals with the ir-orbitals on the alkynyl ligand. The M-C bonds in alkynyl complexes appear to be considerably stronger than those in methyl, phenyl, or vinyl complexes. Alkynyl complexes are sometimes prepared from acetylide anions generated from terminal alkynes and lithium bases (e.g., method A in Equation 3.42), but the acidity of alkynyl C-H bonds, particularly after coordination of the alkyne to the transition metal, makes it possible to form alkynyl complexes from alkynes and relatively weak bases (e.g., method B in Equation 3.42). Alkynyl copper complexes are easily prepared and often used to make alkynylnickel, -palladium, or -platinum complexes by transmetallation (Equation 3.43). This reaction is a step in the preparation of Ni, Pd, or Pt alkynyl complexes from an alkyne, base, and a catalytic amoimt of Cul (Equation 3.44). This protocol for... 

Hissler M, Connick WB, Geiger DK et al (2000) Platinum diiminebis (acetylide) complexes synthesis, characterization, and luminescence properties. Inorg Chem 39 447 57... 

Oxidative addition steps are an important feature in the mechanisms of reactions of Pt(alkyne)(PPh3)a complexes with protonic acids (c/. Scheme 2 in Chapter 2), of reaction of Pt(PMePha)4 with chloroalkenes to give platinum(n) acetylides, and of Pt(PPhs)4 with nitromethane, in benzene-ethanol-water solvent, which provides a safe route to the fulminato-complex Pt(CNO)a(PPh3)2. ... 

Bruce et al. [28] looked at the effect of changing the acetylide ligand to make it longer and more structurally anisotropic, 17. They found that platinum complexes show enantiotropic nematic phase, and that increasing the size of the phosphine decreases the temperatures of transition. 

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