Platin(0)‐Komplexe mit amino‐substituierten Alkinen: Neue Metallorganische Bausteine für supramolekulare Architekturen und „Kristall‐Engineering”︁

Abstract

Professor Lothar Beyer zum 65. Geburtstag gewidmet Inhaltsu È bersicht. Homoleptische Bis(alkin)platin(0)-Verbindungen mit NH 2 -bzw. NH 2 -und OH-Substituenten sind durch Reaktion von Pt(cod) 2 mit Alkinen als stabile Verbindungen herstellbar und als variable Bausteine fu È r supramolekulare Verba È nde verwendbar. Die Kristallstrukturanalysen von Bis(2-Amino-2,5-dimethyl-5-hydroxy-hex-3-in)platin (0) (1) und von Bis(1-(3-Amino-3-methyl-but-1-inyl)-cyclohexan-1-ol)platin(0) (2) zeigen, dass Pt 0 tetraedrisch von den vier sphybridisierten Kohlenstoffatomen der Alkine umgeben ist. Trotz gleicher Bindungsla Èngen und -winkel der PtC 4 -Tetraeder ist die supramolekulare Verknu È pfung verschieden. Wa Èh-rend in 1 polymere Stra Ènge gebildet werden, in denen die Bis(alkin)-Platin(0)-Einheiten durch (OH) 2 (NH 2 ) 2 -Tetraeder verknu È pft sind, bildet 2 nur ein Dimer, das u È ber ein H-Bru È -ckennetzwerk von vier OH-und zwei NH 2 -Gruppen verbunden ist.Auch Alkin-Platin(0)-Komplexe mit kationischen Alkinliganden, die Ammoniumsubstituenten an den Alkinen enthalten, sind als thermisch stabile Verbindungen isolierbar. Die Kristallstrukturanalyse von [Cl(FH + )Pt(cod)] 4 (8) weist aus, dass vier molekulare Einheiten einen Kubus bilden, mit je vier NH 3 + -Gruppen und Cl ± an den Ecken, die durch Wasserstoffbru È cken zusammengehalten werden. Im Bis-(alkin)Platin(0)-Komplex [Cl 1,5 (FH + ) 1,5 (F) 0,5 Pt] (9) sind nur 1,5 von zwei NH 2 -Gruppen protoniert, und ein Netzwerk von Wasserstoffbru È cken verknu È pft vier Bis(alkin)Platin(0)-Einheiten miteinander. (cod: cycloocta-1,5-dien, F: 1-(Trimethylsilylethinyl)-1-amino-cyclohexan). Platinum(0) Complexes with Amino-Substituted Alkynes: Novel Organometallic Building Blocks for Supramolecular Architectures and ªCrystal EngineeringºAbstract. Homoleptic Bis(alkyne)platinum(0) compounds containing either NH 2 -or NH 2 -/OH-substituents are formed by reaction of Pt(cod) 2 with alkynes as stable compounds. They can be used as variable building blocks for supramolecular networks. The crystal structure analyses of Bis(2-amino-2,5-dimethyl-5-hydroxy-hex-3-yne)platinum(0) (1) and of Bis(1-(3-amino-3-methyl-but-1-inyl)-cyclohexane-1-ol)platinum(0) (2) exhibit that the low-valent Pt atom is tetrahedrally surrounded by the four sp-hybridizated carbonatoms of the alkynes. Despite the fact that the bond lengths and -angles of the PtC 4 units are equal, the supramolecular structures are different. While in 1 polymer strands are formed in which the bis-(alkyne)-Pt 0 units are connected by (OH) 2 (NH 2 ) 2 -tetrahedrons, 2 yields only a dimer containing a network of four OHand two NH 2 -groups.Platinum(0) complexes with cationic alkynes bearing ammonium substituents can be isolated as thermal stable compounds. The X-ray structures of [Cl(FH + )Pt(cod)] 4 (8) reveals that four molecular units form a cube with both four NH 3 + groups and Cl ± at the corners connected by hydrogen bridges. In the bis(alkyne)Pt 0 complex [Cl 1.5 (FH + ) 1.5 (F) 0.5 Pt] (9) only 1,33 of two NH 2 groups are proto...

A new synthesis for thermolabile low-valent palladium complexes by electron transfer reactions from nickel(0) to palladium(II) compounds

“…The crystal structure of 3 shows it to be very similar to the closely related M(cod) 2 complexes of Ni(0) and Pt(0) [1,24] with the Pd(0) centre in a tetrahedral environment of the centroids of the olefin groups of the two chelating cod ligands. The Pd-C bond distances lie in the range usually observed for this type of bonding and need therefore no further discussion.…”

“…Yield: 0.064 g (50%); C 21 H 30 Pd (388.87); the spectroscopic properties of the compound were identical with those of an authentic sample [23]. 1 6 The reaction was carried out as stated above for the preparation of Pd(cod) 2 in the presence of 1,3-butadiened 6 instead of 1,3-butadiene. The crude white product was extracted with heptane and analysed by mass spectroscopy.…”

“…Recently we have found that [Ni(bpy)(cod)] reduced Pt(cod)Cl 2 to form Pt(cod) 2 which could be isolated in good yields [1]. From this finding the question arises whether this type of electron transfer reaction may have a more general preparative value for the formation of low-valent transition metal complexes which often require very sophisticated reaction conditions, particularly if the resulting reduced products are very reactive.…”

Expedient, Direct Synthesis of (L)Pt(0)(1,6-diene) Complexes from H2PtCl6

“…Pregosin and Caseri described an interesting process based upon the reduction of PtCl 2 (CH 2 CHPh) 2 by Ph 3 SiH, in the presence of excess styrene, to afford the extremely sensitive Pt(0)(CH 2 CHPh) 3 complex. However, the scope of this method remains to be delineated. , Another reduction protocol relies upon the electron-transfer reaction between a Ni(0) derivative ([Ni(bpy)(cod)] (bpy = 2,20-bipyridine)) and a Pt(II) complex, to yield the corresponding Pt(0) species . Unfortunately, this approach requires the use of Ni(cod) 2 , which is difficult to handle.…”

“…25,26 Another reduction protocol relies upon the electron-transfer reaction between a Ni(0) derivative ([Ni(bpy)(cod)] (bpy ) 2,20bipyridine)) and a Pt(II) complex, to yield the corresponding Pt(0) species. 27 Unfortunately, this approach requires the use of Ni(cod) 2 , which is difficult to handle.…”