Abstract: The process for preparing a compound of the formula:Cp'YNHRwherein: Cp' is a cyclopentadienyl or a substituted cyclopentadienyl group, Y is a covalent bridging group which contains one or more group 14 elements, and R is a C.sub.1 to C.sub.20 hydrocarbyl or substituted hydrocarbyl group, the process comprising reacting a ligand of the formula Cp'YX, wherein Cp' and Y are as defined above and X is halogen, with a substantially equimolar amount of a primary amine of the formula NH.sub.2 R, wherein R is as defined above, in an inert solvent in the presence of a HX scavenger at an elevated temperature of at least about 35.degree. C., so as to form said compound.

Abstract: A safety circuit for a marine signal device adapted to be fired after being dropped into sea water. The device has a casing which will allow the water to enter when ready for firing. A salt water battery, a water pressure operated switch and an electric blasting cap are all connected in series within the casing. A resistor of selected value is connected across the terminals of the battery so that the battery will be discharged in a predetermined time if the blasting cap fails to be detonated by the action of water pressure on the switch at a predetermined depth. Furthermore, a shunt is provided between the leads of the blasting cap to reduce the hazards during handling due to static charges or radio frequencies. The shunt may be manually removed prior to firing or in one embodiment the pressure operated switch automatically disconnects the shunt when the switch is operated by water pressure.