Syntheses and X-ray crystal structures of dumbbell-shaped bis-fullerene tungsten and molybdenum complexes

Abstract

In the first neutral bis-fullerene complexes with tungsten(0) and molybdenum(0) [M(h 2 -C 60 ) 2 (CO) 2 (dbcbipy)] [M = W and Mo, dbcbipy = 4,4A-di(butyl carboxyl)-2,2A-bipyridine] synthesized in solution, the metal atom coordination is distorted octahedral with two CO groups and the bipy group of dbcbipy in the equatorial plane and the metal atom binding in an h 2 -fashion to C-C bonds of two C 60 at axial orientation to give a dumbbell shaped molecule.

Tuning the interactions between electron spins in fullerene-based triad systems

“…In addition, combining two fullerene cages within the same molecule increases the total spin-carrying capacity and introduces a mechanism of spin-tuning while retaining the intrinsic properties of each of the fullerene cages [ 10 ]. The synthesis of such fullerene–bridge–fullerene triads, though not straightforward, has been reported [ 11 ], the simplest involving species where the fullerene cages are connected directly by a C–C bond [ 12 ], a bridging O-atom [ 13 ], or by a transition metal atom [ 14 ]. A variety of more complex triads have since evolved in which the fullerene molecules are connected using optically or electrochemically active spacers [ 15 ].…”

Transition Metal Complex Formation

“…Depending on the C 60 :Pd ratio these polymers form linear "pearl necklace" or two-and threedimensional arrangements. The X-ray crystal structure proves the (η 2 -C 60 ) 2 M binding mode (Figure 7.9) [87]. These materials exhibit catalytic activity in the hydrogenation of olefins and acetylenes at room temperature [86].…”

“…Various C 60 M polymer films have been prepared by electrochemical reduction of transition metal complexes of the central metal Pd(II), Pt(II), Ir(I), Rh(I), Rh(II), Rh(III) and Au(I) [89,90]. [87]. [87].…”

The Concentration Control of Magnetic Fullerene C60•‐ Radical Anions in a Crystal Lattice of the (Bu4N+)2{(C60•‐)⋅C6H4Cl2}x{[CpMo(CO)2C60]−}2‐x (x=1, 0.74) Complexes

“…Bands at 452 and 715 nm were attributed to charge transfer from metal to fullerene . These bands were observed in different transition metal complexes with neutral fullerenes ,,–,,. The spectrum of 1 (Figure ) is a superposition of the absorption bands of {CpMo(CO) 2 C 60 } − at 450 and 714 nm and the C 60 •‐ radical anions which shows intense bands in the NIR range at 930 and 1070 nm.…”

“…That can be realized at charge transfer from metal to C 60 . However, in spite of that metals show relatively strong donor properties in zero oxidation state, no charge transfer was found in these complexes ,,–,. Several anionic complexes of fullerenes with metal carbonylates were obtained: (PPN + ){Co(CO) 3 ( η 2 –C 60 )} − , (PPN + ){M(CO) 4 ( η 2 –C 60 )} − (M=Mn and Re) and (PPN + ){CpM(CO) 2 ( η 2 –C 60 )} − (M = Mo and W, PPN + is bis(triphenylphosphoranylidene)ammonium cation) .…”