The tight binding band electronic structures of the molecular conductors X[M(dmit)2]2 (X = TTF, (CH3)4N ; M = Ni, Pd) are reported. In the cases of TTF(Ni(dmit)2] 2, α- and α'-TTF [Pd(dmit)2]2, it is shown that both the LUMO (lowest unoccupied molecular orbital) and HOMO (highest occupied molecular orbital) bands of the acceptor are partially filled. Our calculations show that these phases are quasi-1D metals. The wave vectors of the experimentally observed CDW (charge density wave) instabilities are discussed on the basis of these results. The crucial role of dimerization within the acceptor stacks is emphasized. In dimerized systems like (CH 3)4N[Ni(dmit)2]2 and δ-TTF[Pd(dmit) 2]2 only one band of the acceptor is partially filled according to our calculations. It is suggested that the metal-semiconductor transition at 120 K of the latter phase could be due to nesting of the Fermi surface

A study of the charge density in a-glycine, C2HsNO2, has been carried out employing X-ray and neutron diffraction data measured at 120 K. The crystal is monoclinic, space group P21/n, with the following cell dimensions: a = 5.084(1), b = 11.820(2), c = 5.458 (1) A and fl = 111.95 (2) °. The X-ray data were collected in the sin 0/4 range 0.00-1.20A-k The deformation densities were computed both by the X-N method, using positional and thermal parameters from the neutron diffraction study, and by a multipole refinement method, where the asphericity in the electron charge distribution was accounted for in the refinement. Well defined peaks of deformation charge density are found in all covalent bonds. The positions of the peaks, however, vary slightly depending on the method used. The X-N maps in the bonding regions are * Hydrogen-Bond Studies. CXL. t Present address:

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The reaction of [Cp 2 Ti(CCPh) 2 ], [Cp 2 Zr(CCPh) 2 ], or [(C 5 H 4 Si-Me 3 ) 2 Zr(CCPh) 2 ] with vanadocene in toluene at room temperature gives [Cp 2 V(m-h 2 :h 4 -butadiyne)MCp ' 2 ] 1 (M Ti, Cp' C 5 H 5 ), 2 (M Zr, Cp' C 5 H 5 ), or 3 (M Zr, Cp' C 5 H 4 SiMe 3 ), respectively. These compounds, which have been characterized by elemental analysis, mass spectrometry, IR and Raman spectroscopy, exhibit similar magnetic susceptibilities. According to an X-ray diffraction analysis of 3, the [Cp 2 V] and Cp ' 2 Zr metallocene moieties are bonded to a butadiene (or butadiyne) framework through the two internal carbon atoms for [Cp 2 V], and though the two internal and the two external carbon atoms for [Cp '2 Zr]. The two internal carbon atoms of the butadiene skeleton are planar and tetracoordinated. 1101 s(alkynyl)metallocene, [Cp ' 2 M(C CPh) 2 ], and vanadocene. These compounds have been characterized by mass spectrometry, magnetic susceptiblity measurements, and IR and Raman spectroscopy. The structural arrangement in compounds has been confirmed by an X-ray crystal structure determination of compound 3.

Cyclotetraphosphazanes 2 and 5 obtained from 1,2-diamines are 1,3,2-diazaphosphole oligomers leading to the monomeric form by either thermal equilibrium or by complexing with boron trifluoride. The dicoordinated form stabilized by an orthophenylene ring could explain the reactivity of 4,5-benzo 1,3,2-diazaphosphole 3 with compounds having a mobile hydrogen; these reactions were a 1.2 type addition while butanol led to a 1.1 type addition with complexed 1,3,2-diazaphospholes 4 and 8.

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