Anton B. Burg

Nitrogen bond strain effects in the chemistry of ring-amino boron hydrides

Abstract Compounds of the types (R 2 NBH 2 ) 2 and R 2 NB 2 H 5 are fairly stable even though the BNB bond angles are far less than tetrahedral; however, when the N bonds are further strained, as in the ring-amino boron hydrides (C 3 H 6 NBH 2 ) 2 and C 3 H 6 NB 2 H 5 , the result is instability. Attempts to make the still more N-strained (C 2 H 4 NBH 2 ) 2 and C 2 H 4 NB 2 H 5 lead instead to opened-ring products. The full comparison has included synthesis of the new compounds. C 5 H 10 NBH 2 (assoc.; m.p. 110°; b.p. est 202°), C 5 H 10 NB 2 H 5 (liquid; b.p. est. 148°), C 4 H 8 NBH 2 (assoc.; m.p. 34°; b.p. est. 194°), C 4 H 8 NB 2 H 5 (m.p. −63.5°; b.p. est. 122°), (C 3 H 6 NBH 2 ) 2 (m.p. 51·8°; b.p. est. 186°), C 3 H 6 NB 2 H 5 (m.p. −45·4°; −45·4°; b.p. est. 101°), C 2 H 5 NHB 2 H 5 (m.p. −96.4°; b.p. est. 87°), and n -C 3 H 7 NHB 2 H 5 (glass softening −146 to −142°; b.p. est. 121°). The corresponding NBH 3 complexes were observed; and the mono-strained C 2 H 4 NH·BH 3 proved to be pairly stable.

The borane(III) complexes of (CH3)3PPCF3

Abstract Attachment of one or two BH 3 groups to the PCF 3 unit in the bicoordinate-P complex (CH 3 ) 3 PPCF 3 is achieved quantitatively in tetrahydrofuran at −40°. The P-P bond thus is stabilized: both (CH 3 ) 3 PPCF 3 BH 3 and (CH 3 ) 3 PPCF 3 (BH 3 ) 2 are nonvolatile white solids, stable in vacuo at 60°. Their NMR spectra support the argument that the unusual attachment of a second BH 3 group to the same electron-donor atom is due not to rehydridization but to the interaction of B-H bonding electrons with the P 3 d orbitals, relieving the P → B dative bond polarity. The spontaneous decomposition of (CH 3 ) 3 PPCF 3 BH 3 in THF at 25°, or the attack upon (CH 3 ) 3 PPCF 3 (BH 3 ) 2 by a gaseous stream of (CH 3 ) 3 P at 60°, produces much (CH 3 ) 3 PBH 3 but also an oil tentatively interpreted as (CH 3 ) 3 PPCF 3 -BH 2 PHCF 3 . Liquid ammonia also attacks (CH 3 ) 3 PPCF 3 (BH 3 ) 2 to make (CH 3 ) 3 PBH 3 and polymers; aniline attacks it somewhat similarly. Dry HCl apparently converts the BH 3 groups to BH 2 Cl, with little destruction of the P → B bonding.

Chemistry of phosphorus aluminium bonding: Dimethylphosphino-aluminium hydrides and chlorides

Abstract The solvolysis of AlH compounds in liquid dimethylphosphine leads to (CH3)2PAI bonding. The composition (CH3)2PA1H2·(CH3)2PH was formed from LiAlH4 with (CH3)2PCl in liquid (CH3)2PH; and more extensive phosphinolysis occurred with AlCl3 + LiAlH4 (proportions to form AlH3) in liquid (CH3)2PH. Ether solutions were not suitable, for the ether competed in complex formation: only moderately phosphinolysed AlH3 polymers were obtained. The phosphinolysis of LiAlH4 was extensive, with indication of LiHAl[P(CH3)2]3 as a distinct substance. The compositions HAlCl2 and H2AlCl were formed in ether and heated in liquid (CH3)2PH to form benzene-soluble products having compositions represented by the formulas (CH3)2PAlCl2 and [(CH3)2P]2AlCl (mol. wts. uncertain). These seemed to disproportionate during attempts at sublimination in vacuo, with chloride enrichment in the sublimates.

Iodination of dicarbahexaboranes

Abstract : The Al2I6-catalyzed iodination of 4,5-C2B4H8 produces the enantiomorphs 3-IC2B4H7 and 6-IC2B4H7. No HI was observed. The iodination of C2B4H6 (with Al2I6 at 75C.) similarly formed H2 and a 20% yield of 2-IC2B4H5. The nmr and mass spectra of these iodocarboranes were used for identification and structural understanding. Both carboranes resisted the action of mercury salts for the replacement of iodine from boron. The easily formed adduct IC2B4H5:N(CH3)3 probably is a new kind of quaternary ammonium salt. (Author)

Far Infrared and Raman Spectra of Aryliododichlorides

Abstract Several publications have dealt with attempts to assign characteristic infrared frequencies to functions containing polyvalent iodine.1-3 We wish to report here a study of the infrared and Raman spectra of some substituted phenyliododichlorides leading to the assignment of bands in the range 260-285 cm−1 to I-Cl stretching vibrations.

The heterocyclic bisphosphine (CF3PCF2)2

Bis(trifluoromethyl)phosphine reacts with dimethylzinc at 0–25° to form the new four-membered ring compound (CF3PCF2)2, apparently the first example of the P–C–P–C heterocycle.

The strong base trinitrosylcobalt

The new compound (NO)3Co exerts strong-base action through lone-pair electrons on cobalt, as demonstrated especially by its formation of a stable adduct with the weak Lewis acid trimethylboron.