Diisopropylberyllium, m. p. --9-5", is dimeric in benzene solution at 25". Pyrolysis at 200" gives polymeric isopropylberyllium hydride. With trimethylamine, the monomeric adduct Pri,Be-NMe, is formed which loses a mol. of propene and some trimethylamine when heated at 2 0 0 ' .With 1 mol. of dimethylamine, propane and dimethylaminoisopropylberyllium are formed ; the latter decomposes when heated, with formation of propene and dimethylaminoberyllium hydride. Excess of dimethylamine gives bisdimethylaminoberyllium which is trimeric in benzene solution. Some factors which affect the association of organo-metallic compounds are discussed.-DIMETHYLBERYLLIUM, like trimethylaluminium, is a typical electron-deficient compound in that its polymeric structure (Rundle and Snow,

The fragmentation behaviour of organostannanes [SnPh,Et,-, (n = 0-4), SnPh,(CH,*CH,.Ph), spiro-[CH,], > Sn < [CH2I4, SnPh,X (X = F, CI, Br, or I), Sn2R, (R = Et, Ph)], organoplumbanes (PbEt,, PbPh4), and Ph4C have been examined under high resolution a t 70 ev. Parent ions are always of low abundance and decompose mainly by elimination of an odd-electron neutral fragment, whereas M R, + ions are of high abundance and lose even-electron fragments. Most of the ion current is carried by metal-containing species. Appearance-potential measurements on organostannanes have been used to evaluate djssociation-energy differences and dissociation energies in molecular ions.THE volatile alkyls of many elements were used by the mass spectra of a-bonded organometallic com-Aston in his classical isotope studies, but there have pounds. Dibeler and his co-workers 2-4 examined been comparatively few systematic investigations on several organomercury compounds, the tetramethyl derivatives of the Group IVB metals, and other lead V.

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The stable colourless crystalline complex, (Et,P),Pd(H)CI is obtained by the reduction of (Et,P),PdCI, with trimethylgermane at 40". Reduction of (Et,P),PdBr, is slow unless palladium black is added. The analogous reaction with (Et,P),NiBr, gives a highly unstable nickel hydride complex. The reactions are considered to follow a radical chain mechanism.The reactions of (Et,P),Pd(H)CI with the following are reported : KI, HCI-Et,O, NH,-H,O, CCI,, MeSH-KCN, and MeOH-KCN. Unsaturated compounds (CH,:CHCN, PhCiCH, C, F, , C, H, ) also react with it to give a complexity of products.OF the metals, nickel, palladium, and platinum only the latter has been shown t o form a well defined series of hydrido-complexes. These are mostly uninuclear compounds of the type trans-L,Pt (H)X, although two cisuninuclear complexes have been described, cis- (P h,PCH2) ,Pt (H) GePh, and cis-(Ph,P) ,P t (H) C1 .l Preparative methods usually involve the reduction of a bis(tertiary phosphine)platinum dihalide by use of reagents which result in either a strongly basic environment (EtOH + KOH, LiAlH,, N,H,) or an acidic medium (H, which gives HX, HCO,H)., The reason why these methods are unsatisfactory for palladium analogues is that hydridopalladium complexes decompose rapidly in acidic or basic media. " Neutral " reducing agents, which have been applied to the formation of platinum h y d r i d e ~, ~-~ are illustrated in reactions (1)-(3); these reactions are believed to proceed through octahedral plat iniim intermediates.

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Ph6Ge,0, and Me,GeCI has been studied a t 70 ev under high resolution, and that of the organogermanes ( o mtolyl),Ge, Ph,GeX (X = Me, PhCH,. CI, Br. and I), R6Ge, (R = Et, Ph, m-tolyl), (PhCH,),GeH, Me,GeH ,and GeCI, a t low resolution. Almost all the ion-current is carried by rnetal-containing ions and in general the most favoured fragmentation processes are those leading to even-electron ions.MASS spectroscopic studies have been reported for a variety of organo-silanes,l -stannanes,, and -plumbanes and the purpose of this paper is to present a similar study of a representative selection of organogermanes, and to draw attention to significant differences. Organogermanes the mass spectra of which have already been reported include Me,Ge,, Pri4Ge, Pri,GePrn, ( Pri2GeO),, Pri6Ge2,, (CHiC),Ge,5 and Et,GeR (R = CiCCHXH,, CiCCHXHCH,, CiCC(Me):CH,) and in addition some organogermanes have been identified from their molecularIn a preliminary communication lo we summarised the main features of interest observed in the mass spectra of organo-germanes and -stannanes.

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