Treatment of SiEt3(CH=CH2) with ZrCp2HCl (Schwartz's reagent) followed by reaction with PPh2Cl provides a high-yield (75%) route to Ph2PCH2CH2SiEt3, and accordingly hydrozirconation of CH2=CHCH2SiHMe2 affords the intermediate ZrCp2(CH2CH2CH2SiHMe2)CI (2). The latter, which is very sensitive to hydrolysis and reacts with HCl forming SiHMe2Prn and with NBS or I-2 affording SiHMe2CH2CH2CH2X (X = Br (3), I (4)), behaves similarly with PPh2Cl, PPhCl2, or PBr3 undergoing cleavage to the known Ph2PCH2CH2CH2SiMe2H (i.e. chelH, A) and the novel bis- and tris(silylpropyl)phosphines PhP(CH2CH2CH2SiMe2H)(2) (5) and P(CH2CH2CH2SiMe2H)(3) (6), respectively, with concomitant formation of ZrCp2Cl2. Corresponding hydroboration of allylsilanes is facile, but subsequent phosphine halide cleavage yields (phosphinoalkyl)silanes only as constituents of intractable mixtures. Hydrozirconation followed by phosphination with PPh2Cl also converts SiHMe(CH2CH=CH2)2 to SiHMe(CH2-CH2CH2PPh2)(2) (i.e. biPSiH, B) together with a propyl analogue Ph2PCH2CH2CH2SiMe(Pr-n)H (7) of A (ca. 2:1 ratio), as well as SiH(CH2CH=CH2)(3) to a mixture (ca. 5:2:1 ratio) of SiH(CH2CH2CH2PPh2)(3) (i.e. triPSiH, C), a new analogue SiH(Pr-n)(CH2CH2CH2PPh2)(2) (8) Of B, and a further analogue Ph2PCH2CH2CH2SiHPr2n (9) of A. A further analogue SiH2(CH2CH2CH2PPh2)2 (10) of biPSiH (B) is obtained similarly starting from SiH2(CH2CH=CH2)(2). Steric control of silylalkyl cleavage from 2 is indicated by the fact that, like PPh2Cl (which forms B), two further biPSiH analogues SiH(Me)[CH2CH2CH2P(n-hex)(2)](2) (11) and SiH(Me)(CH(2)CH(2)CH(2)PPhBz)(2) (12) were obtained using P(n-hex)(2)Cl tie. n-hex = CH3(CH2)(4)CH2-) or PPhBzCl (i.e. Bz = -CH2C6H5), respectively, whereas neither (PPr2Cl)-Cl-i nor (PBu2Cl)-Cl-t led to (phosphinoalkyl)silane formation. The surface-substrate linking reagent Ph2PCH2CH2CH2Si(OEt)(3) (D) is formed efficiently by similar means from Si(OEt)(3)(CH2CH=CH2). NMR data (H-1, C-13, Si-29, P-31) for 2-12 have been measured and are discussed.