Synthesis and reactivity of phosphine-substituted hydrido silyl complexes mer-[FeH(SiR3)(CO)3{Ph2P(CH2)nPPh2}](n= 1 or 4), mer-[FeH{Si(OMe)3}(CO)3(PPh2H)] and mer-[FeH{Si(OMe)3}(CO)3{Ph2PCH2C(O)Ph}]. Synthesis of bimetallic complexes and crystal structure of mer-[(Ph3P)Cu(µ-dppm)Fe{Si(OMe)3}(CO)3]