The role of charge assisted C-Hδ+---Oδ- and C-Hδ+---Fδ- hydrogen bonds in organometallic crystals

Weak hydrogen bonding interactions between organometallic cations and organic and inorganic anions have been discussed. It has been shown that charge assisted C-H--O hydrogen bonds can be used in conjunction with strong O-H---O bonds to prepare organic organometallic crystals in which the organic molecule (usually an organic acid) self assembles into three-dimensional networks around organometallic cations. Hydrogen bonding interactions of the C-H---F type have also been investigated in organometallic salts containing PF6- and BF4- anions. These weak interactions are reinforced by the opposite charge present on the ionic components, and have been shown to be responsible for the crystal stability and the phase transitional behaviour of some organometallic systems.