On the Way to Heptahexaenylidene Complexes:  Trapping of an Intermediate with the Novel MCCCCCCCR₂ Moiety

Abstract

Sequential treatment of the in situ generated heptatriyne Me 3 SiCtCCtCCtCC(NMe 2 ) 3 with n-BuLi, (CO) 5 W [THF], and BF 3 ‚OEt 2 affords the first alkenylsubstituted pentatetraenylidene complex, (CO) 5 WdCd CdCdCdC(NMe 2 )C(H)dC(NMe 2 ) 2 ( 4), via addition of dimethylamine to the C dC ζ bond of the intermediate heptahexaenylidene complex (CO) In addition, the alkynyl(butatrienyl)carbene complex (CO) 5 WdC(CtCSiMe 3 )C(Bu)dCd CdC(NMe 2 ) 2 ( 5) is formed.

Coulomb blockade in molecular quantum dots

“…The most popular types are organic molecules [1], where conduction is due to π-conjugated molecular orbitals. In particular, linear carbon-atom chains containing up to 20 atoms connected at the ends to metal atoms have been synthesized [19] and recognized as ideal one-dimensional wires [20]. As an example, we have studied a linear chain containing 12 carbon atoms weakly connected to the metal electrodes at the ends.…”

Atomic chains of group-IV elements and III-V and II-VI binary compounds studied by a first-principles pseudopotential method

“…The linear atomic chain of carbon is even a better conductor than gold chain. 21,22 Although nanowires of metallic elements, 23 carbon nanotubes, 24 and atomic strings of carbon 22,[25][26][27][28] have been investigated extensively, studying similar forms of other group-IV elements ͑Si, Ge, Sn͒ and III-V ͑such as BN, AlP, GaAs, etc.͒ and II-VI ͑CdS, ZnSe, etc.͒ compounds are relatively recent. [29][30][31][32][33][34][35][36][37][38][39] These materials, which have covalent or polar semiconductor crystal forms in bulk, as well as quasi-two-dimensional and finite cross-section onedimensional ͑1D͒ geometries, 40,41 are used in important optoelectronic applications.…”

“…44 The synthesis of stable finite-size carbon 25,26 and silicon 39 atomic chains has been one of the principle factors that motivated the present theoretical study. The atomic chain structures that we consider constitute the ultimate lower limit in thickness of the silicon and compound nanowires that have been studied actively.…”

Nonlinear transport through a finite Hubbard chain connected to the electrodes

“…For simplicity and to give a clear physical interpretation of obtained results, we analyze a finite Hubbard chain of size N, which is connected to the electrodes treated within a broad-band theory. In practice, linear carbon-atom chains containing up to 20 N = atoms connected at the ends to metal atoms have been synthesized [8] and recognized as ideal one-dimensional wires [9,10]. Proposed model can be used to simulate such system by properly matching of model parameters.…”