Two zwitterionic calcium complexes L1CaN(SiMe3)2(THF) (1) and L2CaN(SiMe3)2 (2) via protolysis reaction were synthesized. At ?75 °C, 1 gave a heterotactic sequence enriched polylactide, whilst 2 produced an isotactic polymer.

The side-on end-on dinitrogen complex [PhP(CH(2)SiMe(2)NPh)(2)Ta](μ-H)(2)(μ-η(2):η(1)-N(2)) reacts with CS(2) with complete cleavage of both C=S double bonds and the formation of [PhP(CH(2)SiMe(2)NPh)(2)Ta](μ-S)(2)(μ-CH(2)), which has two bridging sulfides and a bridging methylene unit. Further reaction with H(2) produces CH(4) and the disulfide complex.

Manganocene reacts with LiE(SiMe(3))(2) (E = P or As) to give [(η(5)-Cp)Mn{μ-E(SiMe(3))(2)}](2), where E = P (1) or As (2). The temperature dependence of the magnetic susceptibility in 1 and 2 is due to antiferromagnetic exchange and to spin-crossover (SCO). Compound 2 shows two-step SCO with hysteresis, involving high-spin (S = 5/2) and intermediate-spin S = (3/2) Mn(II).

Complex [(IMes)(2)Pt(H)(ClBC(5)H(4)SiMe(3))] (IMes = 1,3-di(2,4,6-trimethylphenyl)imidazolin-2-ylidene) reacts with Lewis bases (L = pyridine, trimethylphosphine, acetonitrile, tert-butylisocyanide) to generate the kinetically favoured ion pairs [(IMes)(2)Pt(H)(L)][ClBC(5)H(4)SiMe(3)]. Over time, the formation of the thermodynamically favoured borabenzene-L adducts is observed with L = pyridine...

The reaction of GeBr with LiGe(SiMe(3))(3) yields the largest metalloid cluster compound of germanium Ge(14)[Ge(SiMe(3))(3)](5)Li(3)(THF)(6), in which 14 germanium atoms are arranged as a hollow sphere in the cluster core, showing that in the case of germanium also fullerene-like compounds might be present in the borderland between the molecular and solid states.

The problem of partitioning appears in several areas ranging from VLSI, parallel programming, to molecular biology. The interest in finding an optimal partition especially in VLSI has been a hot issue in recent years. In VLSI circuit partitioning, the problem of obtaining a minimum cut is of prime importance. With current trends, partitioning with multiple objectives which includes power, delay...

The reductive cleavage of the Si-Si bond in 1,1-bis(1-methyl-2,3,4,5-tetraphenyl-1-silacyclopentadiene) [(C(4)Ph(4)SiMe)(2)] (1) with either Li or Na in THF gives the silole anion [MeSiC(4)Ph(4)]- (2). The head-to-tail dimerization of the silole anion 2 gives crystals of the disilatricyclic diallylic dianion [(C(4)Ph(4)SiMe)(2)]-2 (3). The derivatization of 3 (crystals) with bromoethane (gas) u...

Epoxide-opening cascades offer the potential to construct complex polyether natural products expeditiously and in a manner that emulates the biogenesis proposed for these compounds. Herein we provide a full account of our development of a strategy that addresses several important challenges of such cascades. The centerpiece of the method is a trimethylsilyl (SiMe(3)) group that serves several p...

In curve fitting problems, the selection of knots in order to get an optimized curve for a shape design is well-known. For large data, this problem needs to be dealt with optimization algorithms avoiding possible local optima and at the same time getting to the desired solution in an iterative fashion. Many evolutionary optimization techniques like genetic algorithm, simulated annealing have al...