I. Kovacs et al., SYNTHESIS AND STRUCTURE OF PHOSPHINOPHOSP HINIDENE-PHOSPHORANES TBU(2)P-P=P(ME)TBU(2)-1, TBU(ME(3)SI)P-P=P(ME)TBU(2)-2, AND TBU(2)P-P=P(BR)TBU(2)-3, Zeitschrift fur anorganische und allgemeine Chemie, 620(12), 1994, pp. 2033-2040
Citations number
23
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Zeitschrift fur anorganische und allgemeine Chemie
A new method for the synthesis of 1 and 2 (Formulae see ''Inhaltsubers
icht'') is reported based on the reaction of 5 with substitution reage
nts (Me(2)SO(4) or CH3CI). The results of the X-ray structure determin
ation of 1 and 2 are given and compared with those of 3. While in 3 on
e P-P distance corresponds to a double bond and the other P-P distance
to a single bond (difference 12.5 pm) the differences of the P-P dist
ances in 1 and 2 are much smaller: 5.28 pm in 1, 4.68 pm in 2. Both 1
and 2 crystallize monoclinic in the space group P2(1)/n (Z = 4). 2 add
itionally contains two disordered molecules of the solvent pentane in
the unit cell. Parameters of 1: a = 884.32(8) pm, b = 1924.67(25) pm,
c = 1277.07(13)pm, beta = 100.816(8)3 and of 2: a = 1101.93(12) pm, b
= 1712.46(18) pm, c = 1395.81(12)pm, beta = 111.159(7)degrees, all dat
a collected at 143 K. The skeleton of the three P atoms is bent (PPP a
ngle 100.95 degrees for 1, 100.29 degrees for 2 and 105.77 degrees for
3). Ab initio SCF calculations are used to discuss the bonding situat
ion in the molecular skeleton of the three P atoms of 1 and 3. The res
ults show a significant contribution of the ionic structure R(2)P-P((-
))-P((+))(X)R(2). The structure with (partially) charged P atoms is st
abilized by bulky polarizable groups R (as tBu) as compared to the ful
ly covalent structure R(2)P-P(X)-PR(2).